review article ion channels and oxidative stress as a...

Review ArticleIon Channels and Oxidative Stress as a Potential Link forthe Diagnosis or Treatment of Liver Diseases

Ana Ramiacuterez1 Alma Yolanda Vaacutezquez-Saacutenchez1

Natalia Carrioacuten-Robalino12 and Javier Camacho1

1Department of Pharmacology Centro de Investigacion y de Estudios Avanzados del Instituto Politecnico NacionalAvenida Instituto Politecnico Nacional 2508 07360 Mexico City DF Mexico2Departamento de Ciencias de la Vida Universidad de las Fuerzas Armadas ESPE Avenida General Ruminahui171-5-231-B Sangolquı Ecuador

Correspondence should be addressed to Javier Camacho fcamachocinvestavmx

Received 23 July 2015 Revised 22 October 2015 Accepted 27 October 2015

Academic Editor Karina R Gordillo

Copyright copy 2016 Ana Ramırez et al This is an open access article distributed under the Creative Commons Attribution Licensewhich permits unrestricted use distribution and reproduction in any medium provided the original work is properly cited

Oxidative stress results from a disturbed balance between oxidation and antioxidant systems Reactive oxygen species (ROS)and reactive nitrogen species (RNS) may be either harmful or beneficial to the cells Ion channels are transmembrane proteinsthat participate in a large variety of cellular functions and have been implicated in the development of a variety of diseases Asignificant amount of the available drugs in the market targets ion channels These proteins have sulfhydryl groups of cysteineand methionine residues in their structure that can be targeted by ROS and RNS altering channel function including gating andconducting properties as well as the corresponding signaling pathways associatedThe regulation of ion channels by ROS has beensuggested to be associated with some pathological conditions including liver diseases This review focuses on understanding therole and the potential association of ion channels and oxidative stress in liver diseases including fibrosis alcoholic liver disease andcancerThe potential association between ion channels and oxidative stress conditions could be used to develop new treatments formajor liver diseases

1 Introduction

Reactive oxygen species (ROS) and reactive nitrogen species(RNS) are produced duringmitochondrial electron transportor by other enzyme systems comprising several oxidore-ductases (such as NADPH oxidase which is critical for thebactericidal action of phagocytes) in all cells types includinghepatocytes [1 2]

ROS play a dual role because they can be either harmfulor beneficial to the cells The normal physiological ROS-mediated processes include cellular growth cell proliferationand regeneration apoptosis and microbial killing by phago-cytes [3] The most relevant ROS in the cell physiology aresuperoxide anion (O

2

minus∙) hydroxyl radical (∙OH) and hydro-gen peroxide (H

2O2) while the more common RNS are nitric

oxide (NO) and peroxynitrite (ONOOminus∙)

ROS generation is essential to maintain cellular functionsand ensure cell survival [4] this is achieved through theactivation of transcription factors such as NF-kappa-B andhypoxia-inducible-factor-1120572 (HIF-1120572) ROS also participatein vascular processes [5] and regulate the activation of theimmune system by acting as intermediates for cytokineslike tumor necrosis factor (TNF-120572) and interleukin-1120573 (IL-1120573) [6 7] However overproduction of ROS andor RNSassociated with a failure in the antioxidant system (superox-ide dismutase catalase and glutathione peroxidase activities[8]) causes cellular oxidative stress that promotes DNAprotein and lipid damage triggering the development ofseveral diseases [9ndash11]

Many oxidative stress-related diseases have been reportedsince the first introduction of this term in 1985 by Sies [12]Some of the most studied conditions are neurodegenerative

Hindawi Publishing CorporationOxidative Medicine and Cellular LongevityVolume 2016 Article ID 3928714 17 pageshttpdxdoiorg10115520163928714

2 Oxidative Medicine and Cellular Longevity

diseases (Alzheimer Parkinson and others) [13ndash16] cellularaging [17] cardiovascular diseases (hypercholesterolaemiaheart failure hypertension myocardial infarction ische-miareperfusion injury and atherosclerosis) [18ndash20] andpathologies involving chronic inflammation [21] Howeverrecent studies have also associated oxidative stress with dia-betes mellitus [22] obesity [23] infectious diseases (HCV[24] malaria [25]) epilepsy [26] chronic pain [27 28] andeven preeclampsia [29]

2 Oxidative Stress and Ion Channels

Ion channels are multimeric proteins located in the plasmamembrane and inner cell compartments forming ion-select-ive pores that open or close in response to specific stimulisuch as membrane potential ligand-binding temperatureand mechanical stimuli [30] ROS and RNS can directlyinduce posttranslational modification of ion channels lead-ing to oxidation nitrosylation andor nitration of specificamino acid residues (sulfhydryl groups or disulfide linkagesinvolving cysteine residues) or indirectly modulate channelfunction by affecting the signaling pathways that controlgene transcription trafficking and turnover [31 32] Theassociation of ion channels in oxidative stress-related diseasesis reported mostly in cardiovascular [33 34] and neurode-generative illnesses [35ndash38] Multiple studies have reportedthe involvement of calcium [39ndash41] potassium [27 30 3642 43] sodium [34] and chloride channels [44 45] in thedevelopment of pathologies where oxidative stress plays amajor role (Table 1) Ion channels have been also suggestedto be associated with oxidative stress in the liver [32 46](Table 2) Next we will describe some of the most studiedplasma membrane and mitochondrial ion channels associ-ated with oxidative stress damage focusing primarily on theirpotential participation in liver pathological conditions

21 Participation of Mitochondrial Ion Channels in DifferentPathologies Generation of high energy molecules is carriedout by the mitochondria electron chain transport hence agreat amount of ROS is generated during thismetabolism [4748] Becausemitochondria are involved in the defense againstROS and its effects on intracellular redox equilibrium thestudy of mitochondria in pathological conditions associatedwith oxidative stress is fundamental [49 50]

There is a huge diversity of ion channels in both the outerand inner mitochondrial membrane (OMM IMM) Someof the ion channels located on the outer and inner mem-brane include voltage dependent anion channel (VDAC)Ca2+ uniporter permeability transition pore (PTP) calcium-activated potassium channels (KCa2+) ATP-sensitive potas-sium channels (KATP) and inner membrane anion channel(IMAC) [51] The field of mitochondrial ion channels hasrecently seen some progress through an integrative approachusing genetics physiology pharmacology and cell biologytools which have helped to elucidate the possible functionsof these channels [52] Some of these ion channels participatein several processes such as apoptosis [53 54] necrosisthermogenesis and volume regulation

The relevance of mitochondrial ion channel research isobserved in numerous studies that have demonstrated its par-ticipation in the development of pathological conditions likeneurodegenerative [35 55] and cardiac diseases [51 56ndash60]Even though mitochondrial dysfunction is associated withdifferent liver pathologies such as alcoholic liver diseases(ALD) [49 50 61 62] metabolic syndromes (insulin resis-tance) [63] and nonalcoholic fatty liver disease (NAFLD)[64] the participation of mitochondrial ion channels in theonset or development of oxidative stress-related liver diseaseshas not been fully explored

Nakagawa et al [65] reported the presence of mitochon-drial ATP-sensitive K+ (mitoKATP) channels in rat primaryhepatocytesThis study demonstrated that diazoxide (a selec-tive opener of mitoKATP channels) enhanced liver regener-ation by keeping a higher ATP content in the liver tissueThey concluded that diazoxide sustains the hepatocytesmitochondrial energetics promoting liver regeneration afterpartial hepatectomywhich is characterized by the presence ofoxidative stress Indeed potassium channel openers acting onmitochondria have proved to reduce cell damage observed inischemia For instance the effect of cromakalim and diazox-ide on cardioprotection against ischemia-reperfusion injuryhas been shown [66] Another study carried out by Shimizu etal [67] assessed the effect of diazoxide against brain damageafter middle cerebral artery occlusion (MCAO) in maleWistar rats The neurological score was improved in animalstreated with diazoxide in comparison with the control groupthe effects of diazoxide were prominent in the cerebral cortexAccordingly the protective effect was reversed with pretreat-ment of 5-hydroxydecanoate a selective blocker ofmitoKATPproving that selective opening of mitoKATP channel hasneuroprotective effects against ischemia-reperfusion injuryin the rat brain

Conductances reported for mitochondrial KATP channelsof different cell types are lower than those reported for plasmamembrane KATP variants under the same ionic condi-tions Moreover Szabo and Zoratti [52] mention that small-conductance Ca2+-activated K+ channels have conductancescompatible with the lower values reported for mitoKATPchannels Pharmacological approaches have their own com-plications due to the nonspecific targeting exhibited bysome mitoKATP inhibitors (5-hydroxydecanoate) and open-ers (such as diazoxide and cromakalim) which can also act onplasma membrane KATP channels according to some stud-ies Activators of KATP and SKCaIKCa (small-conductanceSKCa and intermediate-conductance (IKCa) calcium-acti-vated potassium channels) have structural similarities sug-gesting the possibility of a pharmacological crossover [52]

Interestingly mitochondria associated-endoplasmic reti-culum membranes (MAMs) which are important for Ca2+lipid and metabolite exchange were investigated by Arrudaet al [63] in the liverThey reported that the reorganization ofMAMs in a background of obesity resulted in mitochondrialCa2+ overload which compromised mitochondrial oxidativecapacity and increased oxidative stress Even though thisstudy did not address Ca2+ flux in mitochondria its resultsindicate that obesity drives an abnormal increase in MAMsformation along with an alteration in Ca2+ flux from the ER

Oxidative Medicine and Cellular Longevity 3

Table1Ionchannelsinvolved

inoxidatives

tress-rela

teddiseases

Type

Channel

Type

ofdysregulation

Oxidativ

estre

ss-rela

ted

disease

Mod

elAlteratio

npathop

hysio

logicaleffect

Ref

Na+

voltage-gated

sodium

channels

(VGSC

s)

Na v11

Miss

ense

mutation

Idiopathicepilepsy

Patie

nts

Increase

insodium

influ

xPatientssho

wvaria

bles

eizure

types

inclu

ding

absencemyoclon

icton

ic-clonicandpartialseizures

[2637

193ndash196]

Na v12

Miss

ense

mutation

Na v15

Punctualmutation(SNP)

Coron

arymicrovascular

dysfu

nctio

nandisc

hemic

heartd

isease(IH

D)

Patie

ntspo

pulationstu

dyPo

lymorph

ismrs1805124GGassociated

with

ahigherrisk

todevelopID

H

[34193

195]

Na v16

Largep

ersistent

sodium

current

Neurodegenerativ

edise

ases

Mou

semod

elTh

elarge

persistentcurrent

prod

uced

byNa v16

may

play

arolein

adam

aginginjury

cascadew

hencoexpressedwith

Na+

Ca+

exchangerindemyelin

ated

axon

s

[193195

197]

Na v17

Gain-of-fu

nctio

nmutation

Neuropathicpain

Patie

nts

Hyperexcitabilityof

neuron

sacuteo

rchron

icpain

[28195

198199]

Loss-of-fun

ctionmutation

Con

genitalinsensitivity

topain

Patie

nts

Indifferencetopain

[28195

198ndash200]

Na v18

Gain-of-fu

nctio

nmutation

Neuropathicpain

Patients

Mutations

contrib

utetopainfulp

eripheraln

europathyby

enhancem

ento

fthe

channelrsquosrespon

seto

depo

lariz

ationand

prod

uceh

yperexcitabilityin

DRG

neuron

s

[193195

201]

Na v19

Gain-of-fu

nctio

nmutation

Neuropathicpain

Patients

Gain-of-fu

nctio

nmutations

inthischannelare

suggestedto

contrib

utetopainauton

omicdysfu

nctio

nandaxon

aldegeneratio

nin

patientsw

ithperip

heraln

europathy

[193195

202]

Potassium

channels

K ir61


Coron

arymicrovascular

dysfu

nctio

nandisc

hemic

heartd

isease(IH

D)

Patients

Thep

olym

orph

ismrs5219

AAof

K ir62isassociated

with

aprotectiv

eeffectin

thed

evelo

pmento

fIHD

[34193]

K Ca11

Overactivation

Alzh

eimer

disease(AD)

Mou

semod

elIncreasedavailabilityof

ROSin

mou

semod

elsof

ADsoBK

channelsaree

xtensiv

elyoxidized

[203]

K Ca31

Overexpression

Diabetic

neph

ropathy

Mou

semod

elandhu

man

tissue

Knockout

ofK C

a31redu

cesrenalfib

rosis

inam

ouse

mod

elof

diabeticneph

ropathy

[204]

Voltage-gated

chlorid

echannels(V

GClCs

)CL

IC1

Sing

lenu

cleotide

polymorph

isms

Idiopathicepilepsy

Patie

nts

Possiblecontrib

utionof

theldquo

skele

talrdquochlorid

echann

elClC-

1to

ther

egulationof

brainexcitability

[205]

Acid-sensin

gion

channels

ASIC1

aOverexpressed

HCC

Livertum

ortissues

and

SMMC-

7721

cells

Supp

ressionof

ASIC1120572expressio

nby

RNAiatte

nuates

the

malignant

phenotypeo

fHCC

cells

[206]


Table 2 Ion channels involved in oxidative stress in the liver

Ion channel Pathology Model Oxidative stress effect Reference

Kv21 Hepatoma Huh-7 cell line HCV inhibits Kv21 suppressing apoptosis inresponse to oxidative stress

[24]

Kir62 Acute liver injury LPS-induced mouse model ofliver injury

Kir62 knockout exacerbates LPS-inducedendoplasmic reticulum stress in the liver

[207]

TRPM2 Acetaminophen-inducedliver damage TRPM2 KO mice H

2O2minus and acetaminophen-activated Ca2+ entry

is attenuated in TRPM2 KO mouse hepatocytes[208]

TRPM7 Liver fibrosis Rat hepatic stellate cells Blockage of TRPM7 causes HSC death induced byER stress-mediated apoptosis

[138]

TRPV4 Liver fibrosisHuman liver fibrotic tissuesHSC-T6 cellsRat liver fibrosis model CCl

4

TRPV4 expression correlates with HSC activationand in HSC-T6 induction of 120572-SMA and Col11205721

[144]

P2Y Liver fibrosis Rat liver fibrosis model CCl4

Blockage of P2Y receptors inhibited CCl4-induced

liver fibrosis in rats[131]

P2X7 Liver fibrosisNASH

Mouse liver fibrosis modelCCL4

Mouse diet-induced obesity(DIO)

P2X7 blockage attenuates mouse liver fibrosis andP2X7 gene-deleted mice decreased 120572-SMACol11205721 and TGF-1205731 in DIO treated mice

[117 133]

CLIC1 Hepatocarcinoma Mouse hepatocarcinomaascites cell line (Hca-F)

Overexpression of CLIC1 contributes to cellproliferation apoptosis migration and invasion

[170]

ASIC1a Liver fibrosis Rat liver fibrosis model CCl4

ASIC1a increases in HSC and inhibition of ASIC1asuppresses PDGF-induced profibrogenic effects ofactivated HSC

[160]

VSOR Hepatoma Rat hepatoma (HTC) cells Activated by H2O2regulating cell volume and cell

proliferation[170]

VDAC Acute ethanol intoxication Rat primary hepatocytes

Bax interacts with the PTP component proteinVDAC and likely causes PTP openingcytochrome c release caspase activation andapoptosis

[209]

to mitochondria Transient increase in Ca2+ level activatesmitochondrial matrix enzymes and stimulates oxidativephosphorylation thus a high Ca2+ flux to the mitochondriais detrimental promoting oxidative metabolism and conse-quently ROS production [68]

Mitochondrial ion channels are also considered oncolog-ical targets due to the fact that cancer transformation involvesreprogramming of mitochondrial metabolic and apoptoticfunctions which are necessary to ensure proliferation ofneoplastic cells and promote metastasis [53 69ndash73]

3 Alcoholic Liver Disease

Alcohol is a psychoactive substance with dependence-pro-ducing properties and is considered a causal risk factor fora broad spectrum of diseases and injury conditions includingalcohol dependence liver cirrhosis and cancer [74] Emerg-ing evidence suggests that alcohol consumption is also relatedto the incidence of infectious diseases such as tuberculosisand HIVAIDS [74] Chronic alcohol (ethanol) consumptionis a well-reviewed risk factor of liver diseases [75ndash78] In factat least 15 of alcoholic cirrhosis cases end up in hepatocellu-lar carcinoma (HCC) the most common type of liver cancer[79] which has one of the highest mortality rates worldwide[80]

Many investigations strongly suggest that liver damageproduced by alcohol is mediated through oxidative stress [7681ndash83] The multistage process observed in ethanol-inducedliver diseases (also called alcoholic induced liver diseases(ALD)) covers a broad spectrum of morphological changesfromhepatic steatosis (fatty liver) alcoholic hepatitis chronichepatitis and fibrosis ultimately to cirrhosis which leads tohepatocarcinoma [79] Ethanol abuse is directly involved inthe generation of ROS and RNS that affect the intracellularredox balance within hepatocytes and other cell types in theliver such as immune cells (neutrophils) sinusoidal endothe-lial cells (SECs) Kupffer cells (KCs) and hepatic stellate cells(HSCs) Actually ethanol exposure impairs the structure andfunction of mitochondria thus when ROS production isuncontrolled several responses that promote immune cellactivation are triggered [84]

31 Ethanol-Induced Oxidative Stress The liver oxidizes andcompletely metabolizes alcohol for which cytosolic andmitochondrial enzymes are required Ethanol metabolism iscarried out through three main pathways involving the fol-lowing enzymes alcohol dehydrogenase (ADH) and alde-hyde dehydrogenase (ALDH) microsomal ethanol oxidationsystem (MEOS) via catalysis by cytochrome P450 isoenzymes(2E1 1A2 and 3A4 isoforms) [85] and catalase Any type of


ethanol metabolism will lead to free radical generation thataffects the antioxidant defensive system of the cells [86]

Some of the mechanisms by which ethanol impairs theoxidative balance within hepatic cells are acetaldehyde pro-duction by ADH ethanol-induced hypoxia mitochondriadamage effects on the immune system [87] induction ofCYP2E1 mobilization of iron and alteration of antioxidantenzymes and chemicals [88] Ethanol metabolism causesdepletion of reduced glutathione (GSH) levels and elevatesmalondialdehyde (MDA) hydroxyethyl radical (HER) andhydroxynonenal (HNE) protein adducts [86] leading tostructural and functional abnormalities in the liver More-over alcohol metabolism via CYP2E1 activates stress pro-teins promotes endoplasmic reticulum stress and impairslysosomal function and autophagy [82] Additionally someof the mitochondrial alterations caused by ethanol-inducedoxidative stress are DNA damage ribosomal defects andinhibition of protein synthesis which in turn affects theintegrity of the electron transport chain (complexes I and II)and the oxidative phosphorylation system that is carried bythis organelle [50 79 89]

32 Ion Channels in ALD The association of ion channelsin the mechanism of ethanol-induced oxidative stress to theprogression of ALD remains elusive and represents a veryinteresting field of research The mitochondrial alterationsobserved under these conditions include the mitochondrialmembrane potential and permeability transition (PT) andchanges promoting apoptosis [90] Alteration of mitochon-drial membrane potential has been examined in rat hepa-tocytes exposed to ethanol using rhodamine 123 (Rh123)an indicator of mitochondrial membrane potential Acuteethanol administration decreased mitochondrial membranepotential in hepatocytes within 30min which indicates thatmitochondrial alteration is an early event of ethanol-inducedhepatocyte injury Additionally the increase in PT is inducedby opening of the mitochondrial megachannel also known aspermeability transition pore (PTP) PTP is regulated bymito-chondrial matrix conditions electrical membrane potentialthiols oxidants pH and calcium concentration these arefactors disturbed as a consequence of ethanol metabolism[91]

Furthermore Yan et al [92] evaluated the effect of etha-nol on PTP mitochondrial membrane potential and intra-cellular calcium concentration in cultured hepatocytes MaleWistar rats were administrated intragastrically with alcoholplus olive oil diet the control group was given an equalamount of normal saline Ultramicrostructural changesin mitochondria PTP opening mitochondrial membranepotential mitochondrialmass and intracellular calcium con-centration of isolated hepatocytes weremeasuredThe resultsshowed that the mitochondria of the model group had dif-ferent shapes and that the PTP was disturbed causing mito-chondria swelling Moreover mitochondria transmembranepotential was decreased in comparison with the controlgroup Intracellular calcium concentrationwas also increasedin the liver cells of the group treated with alcohol Theseresults indicate that ethanol-induced chondriosome injurycould be an important early step in ALD pathogenesis

The molecular nature of PTP is not completely solved Inthe last decade findings made by Bernardi and collaborators[93ndash95] suggested that reconstituted dimers of the F

0F1

ATP synthase (or complex V) form a channel that exhibitsidentical properties to those attributed to the mitochondrialmegachannel Indeed dimers of the ATP synthase treatedwith Ca2+ generate currents indistinguishable from MMCwhile monomers lack any channel activity strongly suggest-ing that PTP forms from a specific Ca2+ dependent confor-mation of the dimers Moreover inducers (thiol oxidantsbenzodiazepine (Bz-423)) and inhibitors (Mg2+ adeninenucleotides) of PTP channel opening have the same effect onATP synthase PTP modulators such as membrane potentialand matrix pH also constitute key regulators of the ATPsynthase Open questions remain and further studies areneeded to clarify the effect and mechanism of action of otherPTP regulators (eg rotenone and quinones) and additionalissues concerning the dimer hypothesis According to thesefindings it seems that complex V plays a dual function ATPsynthesis and PTP formation

PTP participates also in mitochondrial calcium release[96] Pioneer work established its role regulating mitochon-drial Ca2+ homeostasis in hepatocytes Cyclosporin A (CsA)is a potent inhibitor of prooxidant-induced release of Ca2+from isolated mitochondria Pretreatment of hepatocyteswith CsA before exposure to prooxidants (tert-butyl hydro-peroxide cumene hydroperoxide or 35-dimethyl-N-acetyl-p-benzoquinone imine) protected hepatocytes from prooxi-dant injuryThis prevented excessive Ca2+ cycling (maintain-ing mitochondrial Ca2+ pool) that leads to alterations of thetransmembrane potential and ATP synthesis and conse-quently compromises mitochondrial functioning and cellsurvival [97]

Participation of HSCs in ALD has been proposed invarious studies [98ndash101] HSCs are located in the space ofDisse (the liver space between a hepatocyte and a sinusoid)and these cells participate in the process of ECM remodeling(collagen secretion etc) after liver injury L-type voltage-operated Ca2+ channels (VOCC) regulate calcium entry intothe cytoplasm and subsequently cell contraction which hasbeen well studied in cardiac and smooth muscle cells HSCsactivated by transforming growth factor-1205731 (TGF-1205731) expressVOCC [102] suggesting that voltage-operated Ca2+ channelscould also regulate hepatic microcirculation via cell contrac-tion Itatsu and collaborators [103] evaluated the effect ofethanol on VOCC in HSCs activation HSCs are known toproliferate in response to liver injury changing from aldquoquiescent phenotyperdquo to the ldquoactivated phenotyperdquo Thisstudy showed that VOCC expression in activated HSCs issignificantly increased after 14 days of ethanol exposurein comparison with untreated cells Ethanol increases thesecretion of TGF-1205731 that also induces ROS productionand downregulates antioxidant enzymes participating infibrogenesis and tumorigenesis [104] however the preciselink between TGF-1205731 oxidative stress and VOCC remainselusive


4 Nonalcoholic Fatty Liver Disease

Nonalcoholic fatty liver disease (NAFLD) is the most com-mon liver disease reported inwestern nations NAFLDpreva-lence is 30ndash45 in Americans Hispanics have the highestprevalence followed by Caucasians and African Americans[105] NAFLD is the accumulation of fat in hepatocytescorresponding to more than 5 of the liver weight inpatients and that is not associated with a significant alcoholconsumption (conventionally defined as an ethanol intakegt20 gday)The histopathological spectrum includes steatosis(fatty liver) and nonalcoholic steatohepatitis (NASH) whichcan progress to cirrhosis and finally to hepatocellular carci-noma NAFLD is associated with the presence of metabolicsyndrome Steatosis is usually associated with a benignprognosis and does not affect overall survival of patientsNASH represents 2ndash5 of NAFLD cases and is relatedto increased mortality [106 107] The pathophysiology ofNASH is complex involving free fatty acid accumulation(fatty liver) hepatic inflammation (cytokine production) andoxidative stress and lipid peroxidation as well as hepatocel-lular damage with or without the presence of fibrosis [108]Oxidative stress triggers necroinflammation in the liver andcontributes to the pathogenesis of NASH ROS generatedduring fatty acid metabolism in microsomes peroxisomesand mitochondria are the main source of oxidative stress[109]

Mitochondrial dysfunction and oxidative stress play animportant role in the pathogenesis of NAFLD observed inrodent models as well as in patients [110 111] Increasedserum oxidative markers such as thioredoxin oxidized LDLand malondialdehyde have been reported in NASH patientsLipid accumulation within hepatocytes impairs oxidativecapacity of the mitochondria stimulating peroxisomal andmicrosomal pathways of fat oxidation which results in lipo-toxicity Oxidative stress then promotes apoptosis of hepaticcells via ATP NAD and glutathione depletion as well as byDNA lipid and protein damage [112]

A few studies on the participation of ion channels in thepathogenesis ofNAFLDorNASHhave been reported Recentinvestigations reported that cation channels may generatecalcium signals during endolysosomal fusion and vesicletrafficking Two-pore channels (TPCs) are cation-selectiveintracellular ion channels expressedmostly in the endosomalsystem (TPC1) and on late endosomes and lysosomes (TPC2)Activation of TPCs mediates calcium release from lysosomalstores TPC2 leads to trafficking defects promoting hepaticcholesterol accumulation hyperlipoproteinaemia and finallyNASH Grimm et al [113] explored the role of TPC2 in vitroand in vivo Embryonic mouse hepatocytes lacking TPC2displayed a significant impairment of LDL-cholesterol andEGFEGF-receptor trafficking which can be attributed toa dysfunction of the endolysosomal degradation pathwayTPC2-deficient mice also presented cholesterol overloadand liver damage consistent with NAFLD These resultssuggest that TPC2 plays an important role in traffickingin the endolysosomal degradation pathway of lipids and ispotentially involved in the homeostatic control of variousmolecules

NAFLD and obesity are frequently associated betweenthem and are characterized by the formation of proteininclusions and ubiquitinated proteins Moreover it has beensuggested that autophagy deregulation during obesity con-tributes to protein inclusion and progression to fatty liverpathologies such as steatohepatitis and HCC To elucidatehow lipotoxicity and obesity can affect autophagy an in vitrosystem in HepG2 cells was established HepG2 cells culturedwith saturated fatty acid exhibited the accumulation ofubiquitinated proteins in soluble inclusion bodies Increasedcytosolic calcium levels in the hepatocytes were observedin an obesity mouse model The calcium channel blockerverapamil was proven to restore autophagic flux and suppressprotein inclusions in both models Verapamil also reducedhepatic lipid droplet accumulation insulin resistance inflam-mation and steatohepatitis which suggest that calciumchannel blockers can be used inNAFLDpathologies [114 115]

5 Fibrosis

Hepatic fibrosis is characterized by the excessive genera-tion and accumulation of extracellular matrix (ECM)constituents particularly collagen (types I and III) andfibronectin Liver fibrosis is a progressive pathology resultingin cirrhosis [116] and ultimately contributes to the develop-ment of hepatocellular carcinoma a malignancy of globalimportance with very poor prognosis [117] A fundamentalcell event in this process is the activation of HSCs intofibrogenic myofibroblast-like cells which is characterizedby the expression of alpha-smooth muscle actin (120572-SMA)[118] Following hepatic injury HSCs become activated bycytokines and ROS released from KCs causing HSCs toproliferate synthesize and secrete ECM components (Fig-ure 1) [119ndash121] Liver fibrogenesis is strongly associated withoxidative stress and itmay be the liver diseasemost frequentlyrelated with changes in ion channels Several studies of ionchannels and liver fibrosis are next described

51 Purinergic Receptors Purinergic receptors have bindingsites for nucleotides like ATP and are divided into ligand-gated (P2X) and G protein-coupled (P2Y) receptors [122123] Diverse roles of the purinergic signals in the liver havebeen described in recent years For example purinergicreceptors are involved in the proliferation [124] and glucosesecretion [125] of hepatocytes They are also related to thesecretion [126 127] proliferation [128] and mechanosensa-tion [129] in cholangiocytes The first evidence relating pur-inergic receptor and fibrosis showed the presence of func-tional P2Y2 P2Y4 and P2Y6 receptors in both quiescent andactivatedHSCs [130] Dranoff et al [131] demonstrated that theadministration of pyridoxal-phosphate-6-azophenyl-2101584041015840-disulfonate (PPADS) a synthetic inhibitor of P2Y receptorsmarkedly inhibited carbon tetrachloride- (CCl

4-) induced

liver fibrosis in rats [131]One of themost studied channels described in liver fibro-

sis is P2X7 [132] Increased mRNA and protein expressionof P2X7 was observed in CCl

4-induced liver fibrosis in mice

compared with vehicle-treated mice The competitive P2X7receptor antagonist A438970 significantly attenuated the


Quiescent hepatic

stellate cells (HSCs)

Activation

Reversion inactivation

Kupffer cell

HSCs activated(Myofibroblast-like cell) HSCs inactivated

Fibrosis Fibrosis

120572-SMACol11205721

P2Y

TRPM7

TRPV4

P2Y

ASIC1a

ROS Oxidative Upregulation of ion channels

Blockage of ion channels

PPADS A438970

Ru

PcTX1TGF-1205731

P2X7

2-APB Gd3+stress

uarr TRPM7

uarr ASIC1a

uarr TRPV4

uarr P2X7

Figure 1 Participation of ion channels in HSCs activation during fibrogenesis Ion channel upregulation including TRPM7 TRPV4 P2X7

and ASIC1a has been reported during the activation of HSCs which is a major event during fibrogenesis Blocking these channels withpyridoxal-phosphate-6-azophenyl-2101584041015840-disulfonate (PPADS) 2-aminoethoxydiphenyl borate (2-APB) andGd3+ ruthenium red (Ru) PcTX1or A438970 reduces proliferation of HSCs and production of profibrotic markers (120572-SMA Col11205721) preventing the progression of fibrosis

CCl4-induced necrosis inflammatory infiltration and cell

injury The antagonist also reduced collagen accumulationand the production of the proinflammatorymediators TNF-120572and IL-1120573 in addition it inhibited the activity of NF-120581B dur-ing inflammation as well as protein expression of profibroticfactors including 120572-SMA and TGF-1205731 [117] Das et al [133]demonstrated that mRNA expressions of 120572-SMA collagentype 1 alpha 1 (Col11205721) and TGF-1205731 were significantlydecreased in P2X7 gene-deleted mice compared with wildtype mice suggesting that P2X7 gene-deleted mice are pro-tected from fibrosis mRNA expression of P2X receptors inhuman LX-2 hTERT and FH11 hepatic stellate cell lines hasalso been demonstrated [134]

52 TRPM7 Channels Transient receptor potential (TRP)channels are a superfamily of cation channels that play criticalroles in detecting environmental changes and stimuli TheTRP melastatin-like 7 (TRPM7) channel is selective mainlyfor Ca2+ and is involved in sustaining intracellular Ca2+homeostasis TRPM7 transcripts are detected in the liver ofzebrafish larvae [135] and rat liver [136] The rat embryonichepatocyte line RLC-18 expresses a TRPM7-like current sug-gested to be associated with the proliferation and differenti-ation of hepatocytes [137] Likewise TRPM7 is expressed inHSCs and liver cells from a rat hepatic fibrosis model [138ndash141] It is also expressed in rat hepatocytes the rat hepatomacells WIF-B cells and a polarized cell line derived fromrat hepatoma-human skin fibroblast cross [139] as well asin H4-IIE cells (rat hepatoma cell line) [140] ParticularlyTRPM7 protein was elevated in fibrotic human liver tissuescompared with normal liver tissue and the upregulation ofthe channel strongly correlated with the increasing levels of120572-SMA and Col11205721 proteins Additionally cultured rat HSC-T6 cells treated with TGF-1205731 showed increased expression of

mRNA and protein levels in a time-dependent manner bymechanisms related to the activation of the TGF-1205731Smad3pathway The elevated channel levels were correlated withthe increasing levels of 120572-SMA and Col11205721 proteins [141]Other studies demonstrated that rat primary HSCs displayedincreased TRPM7 expression with different stimuli includingTGF-1205731 or platelet-derived growth factor (PDGF-BB) whichare some of the main growth factors stimulating the pro-liferation of cultured-activated HSCs This cell proliferationwas decreased by the treatment with different TRPM7 non-specific inhibitors such as 2-aminoethoxydiphenyl borate (2-APB) and Gd3+ Both inhibitors were able to decrease cellviability in a dose-dependent manner via the activation ofthe apoptotic pathway [138 142 143] and decreased theexpression of 120572-SMA and collagen I Indeed the treatmentwith 2-APB and Gd3+ inhibited TRPM7 protein expression[143] It has been also suggested that silencing TRPM7 inthe activated HSCs may promote collagen degradation byincreasing the levels of hepatic matrix metalloproteinases(MMPs) such as MMP-13 and decreasing the levels of tissueinhibitors of metalloproteinases (TIMPs) like TIMP-1 andTIMP-2 expression [141]

53 TRPV4 Increased mRNA and protein levels of TRPvanilloid 4 (TRPV4) have been detected in CCl

4-treated rat

livers and in cultured rat HSC-T6 cells Additionally theexpression of120572-SMADandCol11205721 were elevated according tothe progression of HSC-T6 cell activation and correlated withthe levels of TRPV4The blockage of the channel with ruthe-nium red (a nonspecific TRPV4 channel blocker) or TRPV4silencing inhibited the proliferation of TGF-1205731-treated HSC-T6 cells and decreased profibrotic marker expression TheTRPV4 expressionwas directly regulated bymiR-203 inTGF-1205731-induced HSCs Interestingly increased TRPV4 protein


expression was found in the liver tissues from liver fibrosispatients compared to normal liver [144]

54 Large Conductance Ca2+ and Voltage-Activated K+ Chan-nels The large conductance Ca2+ and voltage-activated K+(KCa11 BK) channels are activated by membrane depolar-ization andor elevations in intracellular Ca2+ concentrationThey are expressed in almost every tissue in the body par-ticipating in numerous cellular functions including the reg-ulation of neurotransmitter release and neuronal excitabil-ity relaxation in smooth muscle cells hormone release inendocrine and exocrine cells and blood pressure control[145 146] Recently attention has been drawn to BK channelsas critical targets of oxidative stress whichmodifies the gatingproperties of the channel and is associated with numerousdiseases [147] mainly those associated with vascular impairvascular relaxation and restricted blood flow [148] Con-traction of smooth vascular cells is given by high elevationsof intracellular Ca2+ which makes the plasma membranepermeable to K+ ions by activating BK channels whichhyperpolarizes the membrane and causes relaxation [149]The participation of BK channels has been studied in themodulation of the intrahepatic vascular tone in normal andcirrhotic livers using male Wistar rats exposed to CCL

4

Cirrhotic livers displayed increased activity of BK channelsand blockage of the channel increased the baseline portalperfusion pressure in cirrhotic livers [150] They also useda vasoconstrictor compound (methoxamine) in combinationwith a channel opener (NS1619) observing a decrease in thebaseline portal perfusion pressure in cirrhotic livers whichindicates the participation of BK channels in the modulationof the intrahepatic vascular tone in cirrhosis Also in normalhuman livers incubating HSCs with the vasodilator NO(nitric oxide) increases the open probability of BK [151]ROS have been considered to inhibit vascular BK channelsTang et al [152] have found that H

2O2greatly inhibits BK

channels by oxidizing a single cysteine residue (Cys911) nearthe intracellular Ca2+ binding site (Ca2+ bowl) in the BK 120572subunit disrupting the Ca2+-dependent activation of thechannel These channels have big amounts of cysteines andmethionines in their 120572 and 120573 subunits [32 147] oxidativemolecules could cause alterations in these amino acids andtherefore impair the channel activity causing importantpathophysiological alterations as it has been seen in vascularrelaxation and blood pressure in different diseases

55 Chloride Channels Chloride channels are ubiquitouslyexpressed and are localized in the plasma membraneand intracellular organelles These channels participate incell volume regulation maintain intracellular pH and areinvolved in transepithelial transport cell cycle and electri-cal excitability [153] Nonspecific chloride channel blockersincluding 441015840-diisothiocyanatostilbene-221015840-disulfonic aciddisodium salt hydrate (DIDS) 5-nitro-2-(3-phenylpropyl-amino)benzoic acid (NPPB) and indanyloxyacetic acid(IAA-94) prevented the increase of intracellular levels ofO2

minus∙ and inhibited the activation of the HSC human cell lineLX-2 induced by the free radical These findings suggest

that the O2

minus∙ radical may enter through chloride channelsproducing the HSC activation which is critical to fibrosisdevelopment [154] Other authors Hawkins et al [155] havedemonstrated that O

2

minus∙ flux across the endothelial cellplasma membrane of immortalized human pulmonarymicrovascular endothelial cells (HPMVEC) occurs throughClC-3 channels and induces intracellular Ca2+ release whichactivates mitochondrial O

2

minus∙ production Also studies inerythrocytes [156] and amniotic cells [157] have providedevidence for O

2

minus∙ transport through anion channels whichcould be effectively blocked by DIDS

56 Acid-Sensing Ion Channels The acid-sensing ion chan-nels (ASICs) are members of the degenerinepithelial Na+channel superfamily which are activated by extracellularprotons and induce an amiloride-sensitive cation current(Na+ gt Ca2+ gt K+) [158] The ASICs family is composed ofmammals by four different genes encoding seven isoformsASIC1a ASIC1b ASIC1b2 ASIC2a ASIC2b ASIC3 andASIC4 [159] ASIC1a which is also permeable to Ca2+ mayplay a role in liver fibrosis because the channel mediatesthe activation of HSCs ASIC1a is normally expressed in ratliver tissue including primary HSCs while protein levelswere significantly increased in liver fibrosis induced by CCl

4

where the channel was mainly expressed in activated HSCsFurthermore the protein levels of ASIC1a increased in adose- and time-dependent manner in PDGF-activated HSCswhile the blockade of ASIC1a by Psalmotoxin (PcTX1) or thedownregulation of the channel by si-RNA reduced the activa-tion of HSCs through the mitogen-activated protein kinases(MAPK) signaling pathway also ASIC1a silencing inhibitedextracellular-signal-regulated kinases 1 and 2 (ERK12) andc-Jun N-terminal kinases (JNK) activation [160]

6 Cancer

HCC represents 80 of primary liver cancers the causesleading to HCC include hepatitis B and hepatitis C virusinfection (HBV and HCV resp) alcoholism NASH andaflatoxin B

1dietary exposure These factors produce chronic

inflammation with severe oxidative stress leading to fibrosisand then cirrhotic livers this is a common initial mechanismfor HCC [161 162] Several ion channels have been studiedin HCC Below we summarize recent studies that associateoxidative stress and ion channels in liver carcinogenesis

61 K+ Channels Potassium channels play an important rolein various biological processes including cell proliferationapoptosis cell volume regulation and migration and angio-genesis of a variety of carcinoma cells [43] Different K+ chan-nels have been reported to be involved in the pathogenesisof HCC The intermediate-conductance Ca2+ activated K+channel 31 (IKCa1 KCa31) is overexpressed in HCC tissue[163] Channel blockade with TRAM-34 inhibited HCC cellproliferation in a time- and dose-dependent manner [163164] TRAM-34 inhibited the activation of NF-120581B [164] andactivated the MAPK signaling pathway in the SK-Hep1an invasive liver cell line The activation of this pathwayis linked with the progression of malignant carcinomas


[165] K+ channels control the membrane potential thusoverexpression in malignant cells is correlated with theprogression of the cell cycle from G1 into the S phase since atransient hyperpolarization is required in this step of the cellcycle KCa31 could maintain the hyperpolarized membranepotential in cancer liver cells which promotes Ca2+ influxand facilitation of mitogenic activation [166] Astemizole anonspecific inhibitor of Kv101 and Kv111 potassium chan-nels significantly decreased cell proliferation and increasedapoptosis in vitro in the liver cancer cell lines HepG2 andHuH7 [167] In the same study the authors observed thatastemizole clearly prevented HCC development in vivoAnother recent finding [168] reported that several potassiumchannels were overexpressed in the liver only in the presenceof the chemical carcinogen diethylnitrosamine when thecarcinogen treatment finished the channel mRNA levelsreturned almost to normal valuesThe authors suggested thatsome potassium channels may serve as carcinogen exposureindicators and that gene expression of the Abcc3 transportermay serve as a liver tumor marker

62 Chloride Channels In response to oxidative stress inhepatocarcinoma two types of chloride channels have beenstudied the volume-sensitive outwardly rectifying (VSOR)Clminus channel and chloride intracellular channel 1 (CLIC1)VSORClminus channels are ubiquitously expressed in various celltypes and are involved in cell volume regulation after osmoticswelling (regulatory volume decrease RVD) but they alsoparticipate in cell proliferation and apoptosis [169] In rathepatoma cells (HTC) H

2O2enhances Src mediated PLC1205741

phosphorylation which subsequently increases intracellularCa2+ levels that activate Ca2+-sensitive pathways causingVSOR Clminus channel activation [170] these channels are alsoactivated by H

2O2in HeLa cells and in both cell lines par-

ticipate in cell volume regulation and cell proliferation [169]Thus activation of VSORs in HTC may provide advantagesin the progression of cancer but further studies are needed toelucidate the potential mechanisms involved CLIC1 proteinhas been found to be overexpressed in liver cancer tissuescompared to noncancerous liver tissue and significantlycorrelated with tumor size metastasis and poor prognosis[45] CLIC1 is overexpressed and promotes cell proliferationmigration and invasion in the mouse hepatocarcinomaascites cell line Hca-F that has the potential to producelymphatic metastasis In accordance silencing CLIC1 geneexpression with shRNA inhibited cell proliferation inducedapoptosis and decreasedmigration and invasion [171]One ofthe possible mechanisms by which CLIC1 mediates invasionis by regulating maspin (tumor suppressor) matrix metallo-proteinases [172] annexin A7 and gelsolin [173]

63 T-Type Ca2+ Channels Oxidative stress induces Ca2+cytoplasmic increase via calcium influx through plasmamembrane channels or calcium release from the endoplasmicreticulum increasing calcium influx into the mitochondriaand nuclei where different signaling pathways take place inthe presence of Ca2+ [174] T-type calcium channels playa role in cell cycle progression in different types of cancer

[70 175 176] The expression of the three T-type calciumchannel subunits was observed in six HCC cell lines (HuH-1 PLCPRF5 SMMC7721 SNU182 SNU449 and SNU475)and in the cell line SNU449 T-type channel blockage withmibefradil decreased cell proliferation [177]

64 P2Y Receptor Extracellular nucleotides such as ATP arereleased from cells in response to various stimuli such asshear stress stretching hypoxia inflammation osmoticswelling and cell death In HCC cell lines the levels ofP2Y2 receptor are enhanced compared with human normalhepatocytes these receptors are involved in ATP-induced[Ca2+]i increase Silencing P2Y2R expression inhibited ATP-induced human HCC cell proliferation and migration andin nude mice that were implanted with human HCC cellsblocking P2Y2R inhibited cell growth [178]

65 Hepatitis C Virus Hepatitis C virus (HCV) infection isa major health problem worldwide an estimated 130ndash170million people of the worldrsquos population are infected withHCV [179] Most of these individuals (around 80) willdevelop chronic liver disease predisposing them to fibrosisand serious clinical outcomes such as cirrhosis and hepa-tocellular carcinoma [180] HCV is an enveloped positive-single stranded RNA virus whose genome encodes a singlepolyprotein that produces mature proteins in the host cellmature viral structural proteins (Core E1 E2 and possiblyp7) and nonstructural proteins (NS2 NS3 NS4A NS4BNS5A and NS5B) [181] Chronic HCV infection is associatedwith elevated levels of ROS and RNS leading to an overallincrease of oxidative stress within the liver of patients thisredox perturbation has been recognized as a key playerin HCV-associated liver diseases Ion channels have beeninvolved in the development of the redox state in hepatocytes[182 183] but their role in hepatitis C virus infection remainslargely unstudied However some studies have reportedchanges in ion channels in the presence of HCV

66 K+ Channels Voltage-gated potassium channels areessential for several cellular processes participating in pro-liferation migration survival and apoptosis [184 185] InHCV-infected cells the NS5A viral protein inhibits apoptosisin response to oxidative stress by disrupting the function ofthe Kv21 channel [24] In response to oxidative stress mixedlineage kinase 3 (MLK3) is activated leading to activation ofp38-MAPK that phosphorylates Kv21 at a serine residue inthe cytoplasmic C terminus (S800) which is then traffickedto the plasma membrane resulting in an outward K+ currentwhich is involved in causing apoptosis NS5A inhibits MLK3activation then preventing Kv21 phosphorylation and chan-nel activity in the plasma membrane and avoiding apoptosis[186] This is advantageous to the infected cells that are ableto avoid apoptosis induced by oxidative stress

67 Chloride Channels Activation of chloride channels isrequired for the life cycle of HCV blocking chloride chan-nels inhibits HCV genome replication and reduces NS5Aexpression [187] This might occur because Clminus channels areresponsible for endosome and lysosomal acidification [153]


which is necessary to initiate entry fusion of HCV envelopeproteins to the membrane and viral genome release [188]HCV induces ROS production in liver infected cells andactivation of chloride channels may take place to maintainthe oxidative state in the infected cells It has been proposedthat when ROS are produced by the NAPDH oxidase thetransfer electrons from the intracellular donor NADPH toextracellular oxygen gives rise to an outward flow of negativecharges that depolarizes the plasmamembrane in leukocytesTo counteract the more negative potential the activation ofchloride channels may take place modifying the membranepotential and allowing an optimal ROS production [44 189]Thus HCV-infected cells may balance the loss of negativecharges in the cell by activating chloride channels

68 P2X Receptors P2X receptors regulate proliferation andglucose release in hepatocytes [125 190] Transcripts of P2X1P2X2 P2X3 P2X4 and P2X7 have been observed in rat livercells and rat hepatocytes [125] Huh-7 cells transfected withthe HCV proteins E1E2 showed increased P2X4 gene expres-sion in comparisonwith controlHuh-7 cells [191] P2X4 is oneof the most responsive subtypes of P2X receptors and mayparticipate in mediating glucose-release via glycogenolysis[192]

7 Conclusions

Ion channels play an important role in cellular processesassociated with oxidative stress in health and disease Theseproteins are very important pharmacological targets forseveral human pathologies Therefore more research on theparticipation of ion channels in oxidative stress-associatedliver diseases should help to find new early-detection toolsas well as novel therapeutic strategies

Abbreviations

ASICs Acid-sensing ion channelsANT Adenine nucleotide translocatorADH Alcohol dehydrogenaseALD Alcoholic liver diseasesALDH Aldehyde dehydrogenase120572-SMA Alpha-smooth muscle actin2-APB 2-Aminoethoxydiphenyl borateBz-423 14-BenzodiazepineKATP ATP-sensitive potassium channelsKCa2+ Calcium-activated potassium channelsCCl4 Carbon tetrachloride

CLIC1 Chloride intracellular channel 1Col11205721 Collagen type 1 alpha 1CsA Cyclosporin ADIDS Diisothiocyanatostilbene-221015840-disulfonic

acid disodium salt hydrateER Endoplasmic reticulumEGF Epidermal growth factorECM Extracellular matrixERK12 Extracellular-signal-regulated kinases 1

and 2P2Y G protein-coupled purinergic receptors 2Y

HSCs Hepatic stellate cellsHBV Hepatitis B virusHCV Hepatitis C virusHCC Hepatocellular carcinomaHTC Hepatoma cellsHIVAIDS Human immunodeficiency virus

infection and acquired immunedeficiency syndrome

HER Hydroxyethyl radicalH2O2 Hydrogen peroxide

∙OH Hydroxyl radicalHNE HydroxynonenalHIF-1120572 Hypoxia-inducible-factor-1120572IAA-94 Indanyloxyacetic acidIMAC Inner membrane anion channelIMM Inner mitochondrial membraneIL-1120573 Interleukin-1120573IKCa Intermediate-conductance Ca2+

activated K+ channelJNK c-Jun N-terminal kinasesKCs Kupffer cellsKATP ATP-sensitive K+P2X Ligand-gated purinergic receptorVOCC L-type voltage-operated Ca2+ channelsMAPK Mitogen-activated protein kinasesMDA MalondialdehydeMMPs Matrix metalloproteinasesMCAO Middle cerebral artery occlusionMAMs Mitochondria associated-endoplasmic

reticulum membranesmitoKATP Mitochondrial ATP-sensitive K+MEOS Microsomal ethanol oxidation systemPT Permeability transitionMLK3 Mixed lineage kinase 3NAFLD Nonalcoholic fatty liver diseaseNASH Nonalcoholic steatohepatitisNADH Nicotinamide adenine dinucleotide

(reduced)NO Nitric oxideNPPB 5-Nitro-2-(3-phenylpropyl-

amino)benzoic acidNF-kappa-B Nuclear factor kappa-light-chain-

enhancer of activated B cellsOMM Outer mitochondrial membranePTP Permeability transition poreONOOminus∙ PeroxynitritePLC1205741 Phospholipase C gamma 1PDGF-BB Platelet-derived growth factorPcTX1 PsalmotoxinPPADS Pyridoxal-phosphate-6-azophenyl-

2101584041015840-disulfonateROS Reactive oxygen speciesRNS Reactive nitrogen speciesGSH Reduced glutathioneRVD Regulatory volume decreaseRh123 Rhodamine 123SECs Sinusoidal endothelial cellsSKCa Small-conductance Ca2+ activated

K+ channel


O2

minus∙ Superoxide anionTIMPs Tissue inhibitors of metalloproteinasesTGF-1205731 Transforming growth factor-beta-1TRP Transient receptor potentialTRPM7 Transient receptor potential

melastatin-like 7TRPV4 Transient receptor potential vanilloid 4TNF-120572 Tumor necrosis factor alphaTPCs Two-pore channelsVDAC Voltage dependent anion channelVSOR Volume-sensitive outwardly rectifying

Conflict of Interests

The authors declare that there is no conflict of interestsregarding the publication of this paper

Acknowledgment

The liver disease research related to this topic in the labora-tory ofDr Camachohas been partially funded by theConacytGrant 168102 to Javier Camacho

References

[1] M Marı A Colell A Morales C Von Montfort C Garcia-Ruiz and J C Fernandez-Checa ldquoRedox control of liver func-tion in health and diseaserdquo Antioxidants and Redox Signalingvol 12 no 11 pp 1295ndash1331 2010

[2] H J Forman and M Torres ldquoReactive oxygen species and cellsignaling respiratory burst inmacrophage signalingrdquoAmericanJournal of Respiratory andCritical CareMedicine vol 166 no 12part 2 pp S4ndashS8 2002

[3] C Esquivel-Chirino J Esquivel-Soto J AMorales-Gonzalez etal ldquoInflammatory environmental oxidative stress in tumoralprogressionrdquo in Oxidative Stress and Chronic Degenerative Dis-easesmdashA Role for Antioxidants chapter 8 InTech Rijeka Croa-tia 2013

[4] C Gorrini I S Harris and TWMak ldquoModulation of oxidativestress as an anticancer strategyrdquoNature Reviews DrugDiscoveryvol 12 no 12 pp 931ndash947 2013

[5] M Y Lee and K K Griendling ldquoRedox signaling vascularfunction and hypertensionrdquo Antioxidants and Redox Signalingvol 10 no 6 pp 1045ndash1059 2008

[6] B Poljsak ldquoStrategies for reducing or preventing the generationof oxidative stressrdquo Oxidative Medicine and Cellular Longevityvol 2011 Article ID 194586 15 pages 2011

[7] Z Durackova ldquoSome current insights into oxidative stressrdquoPhysiological Research vol 59 no 4 pp 459ndash469 2010

[8] F Farinati M Piciocchi E Lavezzo M Bortolami and RCardin ldquoOxidative stress and inducible nitric oxide synthaseinduction in carcinogenesisrdquoDigestive Diseases vol 28 no 4-5pp 579ndash584 2010

[9] A A Alfadda and R M Sallam ldquoReactive oxygen species inhealth and diseaserdquo Journal of Biomedicine and Biotechnologyvol 2012 Article ID 936486 14 pages 2012

[10] S Noori ldquoAn overview of oxidative stress and antioxidantdefensive systemrdquo Journal of Clinical amp Cellular Immunologyvol 1 no 8 2012

[11] A Rahal A Kumar V Singh et al ldquoOxidative stress prooxi-dants and antioxidants the interplayrdquo BioMed Research Inter-national vol 2014 Article ID 761264 19 pages 2014

[12] H Sies ldquoOxidative stress introductory remarksrdquo in OxidativeStress pp 1ndash8 Academic Press London UK 1985

[13] B Uttara A V Singh P Zamboni and R T Mahajan ldquoOxida-tive stress and neurodegenerative diseases a review of upstreamanddownstreamantioxidant therapeutic optionsrdquoCurrentNeu-ropharmacology vol 7 no 1 pp 65ndash74 2009

[14] R Thanan S Oikawa Y Hiraku et al ldquoOxidative stress and itssignificant roles in neurodegenerative diseases and cancerrdquoInternational Journal ofMolecular Sciences vol 16 no 1 pp 193ndash217 2014

[15] Y T Chang W Chang N Tsai et al ldquoThe roles of biomarkersof oxidative stress and antioxidant in Alzheimerrsquos disease asystematic reviewrdquo BioMed Research International vol 2014Article ID 182303 14 pages 2014

[16] C Henchcliffe and M F Beal ldquoMitochondrial biology and oxi-dative stress in Parkinson disease pathogenesisrdquoNature ClinicalPractice Neurology vol 4 no 11 pp 600ndash609 2008

[17] W Droge and H M Schipper ldquoOxidative stress and aberrantsignaling in aging and cognitive declinerdquo Aging Cell vol 6 no3 pp 361ndash370 2007

[18] C Ceconi A Boraso A Cargnoni and R Ferrari ldquoOxidativestress in cardiovascular disease myth or factrdquo Archives of Bio-chemistry and Biophysics vol 420 no 2 pp 217ndash221 2003

[19] M Hristova andM Penev ldquoOxidative stress and cardiovasculardiseasesrdquo Trakia Journal of Science vol 12 no 3 pp 296ndash3032014

[20] R Hutcheson and P Rocic ldquoThe metabolic syndrome oxida-tive stress environment and cardiovascular disease the greatexplorationrdquo Experimental Diabetes Research vol 2012 ArticleID 271028 13 pages 2012

[21] S A NoemanH E Hamooda andA A Baalash ldquoBiochemicalstudy of oxidative stressmarkers in the liver kidney and heart ofhigh fat diet induced obesity in ratsrdquoDiabetology andMetabolicSyndrome vol 3 no 1 article 17 2011

[22] A C Maritim R A Sanders and J B Watkins III ldquoDiabetesoxidative stress and antioxidants a reviewrdquo Journal of Biochem-ical and Molecular Toxicology vol 17 no 1 pp 24ndash38 2003

[23] L Marseglia S Manti G DrsquoAngelo et al ldquoOxidative stress inobesity a critical component in human diseasesrdquo InternationalJournal of Molecular Sciences vol 16 no 1 pp 378ndash400 2014

[24] J Mankouri M L Dallas M E Hughes et al ldquoSuppression of apro-apoptotic K+ channel as a mechanism for hepatitis C viruspersistencerdquo Proceedings of the National Academy of Sciences ofthe United States of America vol 106 no 37 pp 15903ndash159082009

[25] S Percario D Moreira B Gomes et al ldquoOxidative stress inmalariardquo International Journal of Molecular Sciences vol 13 no12 pp 16346ndash16372 2012

[26] SWaldbaum andM Patel ldquoMitochondria oxidative stress andtemporal lobe epilepsyrdquo Epilepsy Research vol 88 no 1 pp 23ndash45 2010

[27] E A Afify M M Khedr A G Omar and S A Nasser ldquoTheinvolvement of K(ATP) channels in morphine-induced anti-nociception and hepatic oxidative stress in acute and inflam-matory pain in ratsrdquo Fundamental and Clinical Pharmacologyvol 27 no 6 pp 623ndash631 2013

[28] S D Dib-Hajj T R Cummins J A Black and S G WaxmanldquoFrom genes to pain Nav17 and human pain disordersrdquo Trendsin Neurosciences vol 30 no 11 pp 555ndash563 2007


[29] M Can B Guven S Bektas and I Arikan ldquoOxidative stressand apoptosis in preeclampsiardquo Tissue and Cell vol 46 no 6pp 477ndash481 2014

[30] H Akbarali ldquoOxidative stress and ion channelsrdquo in SystemsBiology of Free Radicals and Antioxidants I Laher Ed pp 355ndash373 Springer Berlin Germany 2014

[31] L Annunziato A Pannaccione M Cataldi et al ldquoModulationof ion channels by reactive oxygen and nitrogen species apathophysiological role in brain agingrdquo Neurobiology of Agingvol 23 no 5 pp 819ndash834 2002

[32] Y Liu and D D Gutterman ldquoOxidative stress and potassiumchannel functionrdquoClinical and Experimental Pharmacology andPhysiology vol 29 no 4 pp 305ndash311 2002

[33] K Takahashi Y Kakimoto K Toda and K Naruse ldquoMechano-biology in cardiac physiology and diseasesrdquo Journal of Cellularand Molecular Medicine vol 17 no 2 pp 225ndash232 2013

[34] F Fedele M Mancone W M Chilian et al ldquoRole of geneticpolymorphisms of ion channels in the pathophysiology of coro-nary microvascular dysfunction and ischemic heart diseaserdquoBasic Research in Cardiology vol 108 no 6 article 387 2013

[35] C Chinopoulos and V Adam-Vizi ldquoCalcium mitochondriaand oxidative stress in neuronal pathology Novel aspects of anenduring themerdquoThe FEBS Journal vol 273 no 3 pp 433ndash4502006

[36] F Sesti S Liu and S-Q Cai ldquoOxidation of potassium channelsby ROS a general mechanism of aging and neurodegenera-tionrdquo Trends in Cell Biology vol 20 no 1 pp 45ndash51 2010

[37] M Mantegazza G Curia G Biagini D S Ragsdale and MAvoli ldquoVoltage-gated sodium channels as therapeutic targets inepilepsy and other neurological disordersrdquo The Lancet Neurol-ogy vol 9 no 4 pp 413ndash424 2010

[38] G Zundorf and G Reiser ldquoCalcium dysregulation and home-ostasis of neural calcium in the molecular mechanisms ofneurodegenerative diseases provide multiple targets for neuro-protectionrdquo Antioxidants and Redox Signaling vol 14 no 7 pp1275ndash1288 2011

[39] M Naziroglu D Merve Dikici and S Dursun ldquoRole of oxida-tive stress and Ca2+ signaling on molecular pathways of neuro-pathic pain in diabetes focus on TRP channelsrdquoNeurochemicalResearch vol 37 no 10 pp 2065ndash2075 2012

[40] J Striessnig A Pinggera G Kaur G Bock and P Tuluc ldquoL-type Ca2+ channels in heart and brainrdquo Wiley InterdisciplinaryReviews Membrane Transport and Signaling vol 3 no 2 pp15ndash38 2014

[41] B Brawek and O Garaschuk ldquoNetwork-wide dysregulation ofcalcium homeostasis in Alzheimerrsquos diseaserdquo Cell and TissueResearch vol 357 no 2 pp 427ndash438 2014

[42] J I Vandenberg ldquoOxidative stress fine-tunes the dance of hERGK+ channelsrdquo Journal of Physiology vol 588 no 16 pp 2975ndash2975 2010

[43] L A Pardo and W Stuhmer ldquoThe roles of K+ channels in can-cerrdquo Nature Reviews Cancer vol 14 no 1 pp 39ndash48 2014

[44] S Averaimo R H Milton M R Duchen and M MazzantildquoChloride intracellular channel 1 (CLIC1) sensor and effectorduring oxidative stressrdquo FEBS Letters vol 584 no 10 pp 2076ndash2084 2010

[45] S Zhang X-M Wang Z-Y Yin et al ldquoChloride intracellularchannel 1 is overexpression in hepatic tumor and correlates witha poor prognosisrdquo APMIS vol 121 no 11 pp 1047ndash1053 2013

[46] F Simon D Varela and C Cabello-Verrugio ldquoOxidative stress-modulated TRPM ion channels in cell dysfunction and patho-logical conditions in humansrdquo Cellular Signalling vol 25 no 7pp 1614ndash1624 2013

[47] A Boveris and B Chance ldquoThe mitochondrial generation ofhydrogen peroxide General properties and effect of hyperbaricoxygenrdquo Biochemical Journal vol 134 no 3 pp 707ndash716 1973

[48] H Sies ldquoRole of metabolic H2O2generation redox signaling

and oxidative stressrdquo Journal of Biological Chemistry vol 289no 13 pp 8735ndash8741 2014

[49] J B Hoek A Cahill and J G Pastorino ldquoAlcohol and mito-chondria a dysfunctional relationshiprdquo Gastroenterology vol122 no 7 pp 2049ndash2063 2002

[50] S M Bailey ldquoA review of the role of reactive oxygen andnitrogen species in alcohol-induced mitochondrial dysfunc-tionrdquo Free Radical Research vol 37 no 6 pp 585ndash596 2003

[51] B OrsquoRourke ldquoPathophysiological and protective roles of mito-chondrial ion channelsrdquo Journal of Physiology vol 529 no 1 pp23ndash36 2000

[52] I Szabo andMZoratti ldquoMitochondrial channels ion fluxes andmorerdquo Physiological Reviews vol 94 no 2 pp 519ndash608 2014

[53] B OrsquoRourke S Cortassa and M A Aon ldquoMitochondrial ionchannels gatekeepers of life and deathrdquo Physiology vol 20 no5 pp 303ndash315 2005

[54] S-Y Ryu P M Peixoto O Teijido L M Dejean and K WKinnally ldquoRole of mitochondrial ion channels in cell deathrdquoBioFactors vol 36 no 4 pp 255ndash263 2010

[55] A A Starkov C Chinopoulos and G Fiskum ldquoMitochondrialcalcium and oxidative stress as mediators of ischemic braininjuryrdquo Cell Calcium vol 36 no 3-4 pp 257ndash264 2004

[56] G J Grover and K D Garlid ldquoATP-sensitive potassium chan-nels a review of their cardioprotective pharmacologyrdquo Journalof Molecular and Cellular Cardiology vol 32 no 4 pp 677ndash6952000

[57] B OrsquoRourke S Cortassa F Akar and M Aon ldquoMitochondrialion channels in cardiac function and dysfunctionrdquo NovartisFoundation Symposia vol 287 pp 140ndash156 2007

[58] G Plank L Zhou J L Greenstein et al ldquoFrom mitochon-drial ion channels to arrhythmias in the heart computationaltechniques to bridge the spatio-temporal scalesrdquo PhilosophicalTransactions of the Royal Society of London Series A Mathe-matical Physical and Engineering Sciences vol 366 no 1879 pp3381ndash3409 2008

[59] PM Peixoto S-Y Ryu and KW Kinnally ldquoMitochondrial ionchannels as therapeutic targetsrdquo FEBS Letters vol 584 no 10pp 2142ndash2152 2010

[60] H Nishida A Matsumoto N Tomono T Hanakai S HaradaandHNakaya ldquoBiochemistry and physiology ofmitochondrialion channels involved in cardioprotectionrdquo FEBS Letters vol584 no 10 pp 2161ndash2166 2010

[61] F Nassir and J A Ibdah ldquoRole of mitochondria in alcoholicliver diseaserdquo World Journal of Gastroenterology vol 20 no 9pp 2136ndash2142 2014

[62] S M Bailey and C C Cunningham ldquoContribution of mito-chondria to oxidative stress associated with alcoholic liver dis-easerdquo Free Radical Biology andMedicine vol 32 no 1 pp 11ndash162002

[63] A P Arruda B M Pers G Parlakgul E Guney K Inouye andG SHotamisligil ldquoChronic enrichment of hepatic endoplasmicreticulummdashmitochondria contact leads to mitochondrial dys-function in obesityrdquo Nature Medicine vol 20 no 12 pp 1427ndash1435 2014


[64] F Nassir and J A Ibdah ldquoRole of mitochondria in nonalcoholicfatty liver diseaserdquo International Journal of Molecular Sciencesvol 15 no 5 pp 8713ndash8742 2014

[65] Y Nakagawa M Yoshioka Y Abe et al ldquoEnhancement of liverregeneration by adenosine triphosphate-sensitive K+ channelopener (diazoxide) after partial hepatectomyrdquo Transplantationvol 93 no 11 pp 1094ndash1100 2012

[66] K D Garlid P Paucek V Yarov-Yarovoy et al ldquoCardioprotec-tive effect of diazoxide and its interaction with mitochondrialATP-sensitive K+ channels possible mechanism of cardiopro-tectionrdquo Circulation Research vol 81 no 6 pp 1072ndash1082 1997

[67] K Shimizu Z Lacza N Rajapakse T Horiguchi J Snipes andD W Busija ldquoMitoKATP opener diazoxide reduces neuronaldamage after middle cerebral artery occlusion in the ratrdquoAmer-ican Journal of PhysiologymdashHeart and Circulatory Physiologyvol 283 no 3 pp H1005ndashH1011 2002

[68] R Rizzuto D De Stefani A Raffaello and C MammucarildquoMitochondria as sensors and regulators of calcium signallingrdquoNature Reviews Molecular Cell Biology vol 13 no 9 pp 566ndash578 2012

[69] L Leanza L Biasutto A Manago E Gulbins M Zoratti andI Szabo ldquoIntracellular ion channels and cancerrdquo Frontiers inPhysiology vol 4 article 227 2013

[70] A Das C Pushparaj J Herreros et al ldquoT-type calcium channelblockers inhibit autophagy and promote apoptosis of malignantmelanoma cellsrdquo Pigment Cell and Melanoma Research vol 26no 6 pp 874ndash885 2013

[71] L Leanza E Venturini S Kadow A Carpinteiro E Gulbinsand K A Becker ldquoTargeting a mitochondrial potassium chan-nel to fight cancerrdquo Cell Calcium vol 58 no 1 pp 131ndash138 2015

[72] L Leanza M Zoratti E Gulbins and I Szabo ldquoMitochondrialion channels as oncological targetsrdquo Oncogene vol 33 no 49pp 5569ndash5581 2014

[73] S M Madamba K N Damri L M Dejean and P M PeixotoldquoMitochondrial ion channels in cancer transformationrdquo Fron-tiers in Oncology vol 5 article 120 2015

[74] WHO Global Status Report on Alcohol and Health 2014 WHOGeneva Switzerland 2014

[75] R Bruha K Dvorak and J Petrtyl ldquoAlcoholic liver diseaserdquoWorld Journal of Hepatology vol 4 no 3 pp 81ndash90 2012

[76] E Ceni T Mello and A Galli ldquoPathogenesis of alcoholicliver disease role of oxidative metabolismrdquo World Journal ofGastroenterology vol 20 no 47 pp 17756ndash17772 2014

[77] B Gao and R Bataller ldquoAlcoholic liver disease pathogenesisand new therapeutic targetsrdquo Gastroenterology vol 141 no 5pp 1572ndash1585 2011

[78] A Gramenzi F Caputo M Biselli et al ldquoReview article Alco-holic liver diseasemdashpathophysiological aspects and risk factorsrdquoAlimentary Pharmacology and Therapeutics vol 24 no 8 pp1151ndash1161 2006

[79] B Sid J Verrax and P B Calderon ldquoRole of oxidative stress inthe pathogenesis of alcohol-induced liver diseaserdquo Free RadicalResearch vol 47 no 11 pp 894ndash904 2013

[80] J Ferlay I Soerjomataram M Ervik et al GLOBOCAN 2012V10 Cancer Incidence and Mortality Worldwide IARC Cancer-Base No 11 International Agency for Research on Cancer LyonFrance 2013

[81] E Albano ldquoOxidative mechanisms in the pathogenesis ofalcoholic liver diseaserdquo Molecular Aspects of Medicine vol 29no 1-2 pp 9ndash16 2008

[82] A Ambade and P Mandrekar ldquoOxidative stress and inflamma-tion essential partners in alcoholic liver diseaserdquo InternationalJournal of Hepatology vol 2012 Article ID 853175 9 pages 2012

[83] J I Beier and C J McClain ldquoMechanisms and cell signaling inalcoholic liver diseaserdquo Biological Chemistry vol 391 no 11 pp1249ndash1264 2010

[84] A M Miller N Horiguchi W-I Jeong S Radaeva and BGao ldquoMolecular mechanisms of alcoholic liver disease innateimmunity and cytokinesrdquo Alcoholism Clinical and Experimen-tal Research vol 35 no 5 pp 787ndash793 2011

[85] C S Lieber ldquoMicrosomal ethanol-oxidizing system (MEOS)the first 30 years (1968ndash1998)mdasha reviewrdquo Alcoholism Clinicaland Experimental Research vol 23 no 6 pp 991ndash1007 1999

[86] S K Das and D M Vasudevan ldquoAlcohol-induced oxidativestressrdquo Life Sciences vol 81 no 3 pp 177ndash187 2007

[87] M Vidali S F Stewart and E Albano ldquoInterplay betweenoxidative stress and immunity in the progression of alcohol-mediated liver injuryrdquo Trends inMolecular Medicine vol 14 no2 pp 63ndash71 2008

[88] A Dey and A I Cederbaum ldquoAlcohol and oxidative liverinjuryrdquo Hepatology vol 43 no 2 supplement 1 pp S63ndashS742006

[89] S M Bailey E C Pietsch and C C Cunningham ldquoEthanolstimulates the production of reactive oxygen species at mito-chondrial complexes I and IIIrdquo Free Radical Biology andMedicine vol 27 no 7-8 pp 891ndash900 1999

[90] M Adachi and H Ishii ldquoRole of mitochondria in alcoholic liverinjuryrdquoFree Radical Biology andMedicine vol 32 no 6 pp 487ndash491 2002

[91] I Kurose H Higuchi S Kato et al ldquoOxidative stress on mito-chondria and cell membrane of cultured rat hepatocytes andperfused liver exposed to ethanolrdquoGastroenterology vol 112 no4 pp 1331ndash1343 1997

[92] M Yan P Zhu H-M Liu H-T Zhang and L Liu ldquoEthanolinduced mitochondria injury and permeability transition poreopening role of mitochondria in alcoholic liver diseaserdquoWorldJournal of Gastroenterology vol 13 no 16 pp 2352ndash2356 2007

[93] P Bernardi ldquoThe mitochondrial permeability transition pore amystery solvedrdquo Frontiers in Physiology vol 4 article 95 2013

[94] P Bernardi A Rasola M Forte and G Lippe ldquoThe mito-chondrial permeability transition pore channel formation byF-ATP synthase integration in signal transduction and role inpathophysiologyrdquo Physiological Reviews vol 95 no 4 pp 1111ndash1155 2015

[95] P Bernardi F Di Lisa F Fogolari and G Lippe ldquoFrom ATP toPTP and back a dual function for the mitochondrial ATPsynthaserdquo Circulation Research vol 116 no 11 pp 1850ndash18622015

[96] C Brenner and M Moulin ldquoPhysiological roles of the perme-ability transition porerdquo Circulation Research vol 111 no 9 pp1237ndash1247 2012

[97] G E N Kass M J Juedes and S Orrenius ldquoCyclosporin aprotects hepatocytes against prooxidant-induced cell killing Astudy on the role of mitochondrial Ca2+ cycling in cytotoxicityrdquoBiochemical Pharmacology vol 44 no 10 pp 1995ndash2003 1992

[98] M L Hautekeete I Dodeman V Azais-Braesco K D VanBerg C Seynaeve andAGeerts ldquoHepatic stellate cells and liverretinoid content in alcoholic liver disease in humansrdquo Alco-holism Clinical and Experimental Research vol 22 no 2 pp494ndash500 1998


[99] N I Han KW Chung B M Ahn et al ldquoUltrastructural chan-ges of hepatic stellate cells in the space of Disse in alcoholic fattyliverrdquoKorean Journal of InternalMedicine vol 16 no 3 pp 160ndash166 2001

[100] M Vera and N Nieto ldquoHepatic stellate cells and alcoholic liverdiseaserdquo Revista Espanola de Enfermedades Digestivas vol 98no 9 pp 674ndash684 2006

[101] J-H Wang R G Batey and J George ldquoRole of ethanol in theregulation of hepatic stellate cell functionrdquo World Journal ofGastroenterology vol 12 no 43 pp 6926ndash6932 2006

[102] H Oide and R G Thurman ldquoHepatic Ito cells contain calciumchannels increases with transforming growth factor-1205731rdquoHepa-tology vol 20 no 4 part 1 pp 1009ndash1014 1994

[103] T Itatsu H Oide S Watanabe M Tateyama R Ochi and NSato ldquoAlcohol stimulates the expression of L-type voltage-oper-ated Ca2+ channels in hepatic stellate cellsrdquo Biochemical andBiophysical Research Communications vol 251 no 2 pp 533ndash537 1998

[104] J Krstic D Trivanovic S Mojsilovic and J F SantibanezldquoTransforming growth factor-beta and oxidative stress inter-play implications in tumorigenesis and cancer progressionrdquoOxidative Medicine and Cellular Longevity vol 2015 Article ID654594 15 pages 2015

[105] C D Williams J Stengel M I Asike et al ldquoPrevalence of non-alcoholic fatty liver disease and nonalcoholic steatohepatitisamong a largely middle-aged population utilizing ultrasoundand liver biopsy a prospective studyrdquoGastroenterology vol 140no 1 pp 124ndash131 2011

[106] C M Fielding and P Angulo ldquoHepatic steatosis and steatohep-atitis are they really two distinct entitiesrdquo Current HepatitisReports vol 13 no 2 pp 151ndash158 2014

[107] S Bellentani F Scaglioni M Marino and G Bedogni ldquoEpi-demiology of non-alcoholic fatty liver diseaserdquo Digestive Dis-eases vol 28 no 1 pp 155ndash161 2010

[108] M Varela-Rey N Embade U Ariz S C Lu J M Mato andML Martınez-Chantar ldquoNon-alcoholic steatohepatitis and ani-mal models understanding the human diseaserdquo InternationalJournal of Biochemistry and Cell Biology vol 41 no 5 pp 969ndash976 2009

[109] A Takaki D Kawai and K Yamamoto ldquoMultiple hits includ-ing oxidative stress as pathogenesis and treatment target innon-alcoholic steatohepatitis (NASH)rdquo International Journal ofMolecular Sciences vol 14 no 10 pp 20704ndash20728 2013

[110] C P M S Oliveira A M M Coelho H V Barbeiro et alldquoLiver mitochondrial dysfunction and oxidative stress in thepathogenesis of experimental nonalcoholic fatty liver diseaserdquoBrazilian Journal of Medical and Biological Research vol 39 no2 pp 189ndash194 2006

[111] S K Das and D M Vasudevan ldquoMonitoring oxidative stress inpatients with non-alcoholic and alcoholic liver diseasesrdquo IndianJournal of Clinical Biochemistry vol 20 no 2 pp 24ndash28 2005

[112] A P Rolo J S Teodoro and C M Palmeira ldquoRole of oxidativestress in the pathogenesis of nonalcoholic steatohepatitisrdquo FreeRadical Biology and Medicine vol 52 no 1 pp 59ndash69 2012

[113] C Grimm LMHoldt C-C Chen et al ldquoHigh susceptibility tofatty liver disease in two-pore channel 2-deficient micerdquoNatureCommunications vol 5 article 4699 2014

[114] HW Park I A Semple I Jang et al ldquoPharmacological correc-tion of obesity-induced autophagy arrest using calcium channelblockersrdquo Nature Communications vol 5 article 4834 2014

[115] H-W Park and JH Lee ldquoCalcium channel blockers as potentialtherapeutics for obesity-associated autophagy defects and fattyliver pathologiesrdquo Autophagy vol 10 no 12 pp 2385ndash23862015

[116] G Poli ldquoPathogenesis of liver fibrosis role of oxidative stressrdquoMolecular Aspects of Medicine vol 21 no 3 pp 49ndash98 2000

[117] CHuangWYuHCui et al ldquoP2X7 blockade attenuatesmouseliver fibrosisrdquo Molecular Medicine Reports vol 9 no 1 pp 57ndash62 2014

[118] R K Moreira ldquoHepatic stellate cells and liver fibrosisrdquo Archivesof Pathology and Laboratory Medicine vol 131 no 11 pp 1728ndash1734 2007

[119] J Jiao S L Friedman and C Aloman ldquoHepatic fibrosisrdquoCurrent Opinion in Gastroenterology vol 25 no 3 pp 223ndash2292009

[120] A Casini E Ceni R Salzano et al ldquoNeutrophil-derived super-oxide anion induces lipid peroxidation and stimulates collagensynthesis in human hepatic stellate cells role of nitric oxiderdquoHepatology vol 25 no 2 pp 361ndash367 1997

[121] P P Simeonova R M Gallucci T Hulderman et al ldquoThe roleof tumor necrosis factor-120572 in liver toxicity inflammationand fibrosis induced by carbon tetrachloriderdquo Toxicology andApplied Pharmacology vol 177 no 2 pp 112ndash120 2001

[122] V Ralevic and G Burnstock ldquoReceptors for purines and pyr-imidinesrdquo Pharmacological Reviews vol 50 no 3 pp 413ndash4921998

[123] D Lu and P A Insel ldquoCellular mechanisms of tissue fibrosis6 Purinergic signaling and response in fibroblasts and tissuefibrosisrdquo The American Journal of PhysiologymdashCell Physiologyvol 306 no 9 pp C779ndashC788 2014

[124] G Beldi Y Wu X Sun et al ldquoRegulated catalysis of extracellu-lar nucleotides by vascular CD39ENTPD1 is required for liverregenerationrdquo Gastroenterology vol 135 no 5 pp 1751ndash17602008

[125] D S Emmett A Feranchak G Kilic et al ldquoCharacterization ofionotrophic purinergic receptors in hepatocytesrdquo Hepatologyvol 47 no 2 pp 698ndash705 2008

[126] J A Dranoff A I Masyuk E A Kruglov N F LaRusso andM H Nathanson ldquoPolarized expression and function of P2YATP receptors in rat bile duct epitheliardquo American Journal ofPhysiologymdashGastrointestinal and Liver Physiology vol 281 no4 pp G1059ndashG1067 2001

[127] N Minagawa J Nagata K Shibao et al ldquoCyclic AMP regulatesbicarbonate secretion in cholangiocytes through release of ATPinto bilerdquo Gastroenterology vol 133 no 5 pp 1592ndash1602 2007

[128] M N Jhandier E A Kruglov E G Lavoie J Sevigny and J ADranoff ldquoPortal fibroblasts regulate the proliferation of bile ductepithelia via expression of NTPDase2rdquoThe Journal of BiologicalChemistry vol 280 no 24 pp 22986ndash22992 2005

[129] A I Masyuk S A Gradilone J M Banales et al ldquoCholan-giocyte primary cilia are chemosensory organelles that detectbiliary nucleotides via P2Y

12purinergic receptorsrdquo American

Journal of PhysiologymdashGastrointestinal and Liver Physiologyvol 295 no 4 pp G725ndashG734 2008

[130] J A Dranoff M Ogawa E A Kruglov et al ldquoExpression ofP2Y nucleotide receptors and ectonucleotidases in quiescentand activated rat hepatic stellate cellsrdquo American Journal ofPhysiologymdashGastrointestinal and Liver Physiology vol 287 no2 pp G417ndashG424 2004


[131] J A Dranoff E A Kruglov O Abreu-Lanfranco T Nguyen GAurora and D Jain ldquoPrevention of liver fibrosis by the puri-noceptor antagonist pyridoxal-phosphate-6-azophenyl-2101584041015840-disulfonate (PPDAS)rdquo In Vivo vol 21 no 6 pp 957ndash966 2007

[132] A Surprenant F Rassendren E Kawashima R A North andG Buell ldquoThe cytolytic P2Z receptor for extracellular ATPidentified as a P2X receptor (P2X7)rdquo Science vol 272 no 5262pp 735ndash738 1996

[133] S Das R K Seth A Kumar et al ldquoPurinergic receptorX7 is a key modulator of metabolic oxidative stress-medi-ated autophagy and inflammation in experimental nonalco-holic steatohepatitisrdquo American Journal of PhysiologymdashGastro-intestinal and Liver Physiology vol 305 no 12 pp G950ndashG9632013

[134] J RGoree E G LavoieM Fausther and J ADranoff ldquoExpres-sion of mediators of purinergic signaling in human liver celllinesrdquo Purinergic Signalling vol 10 no 4 pp 631ndash638 2014

[135] M R Elizondo B L Arduini J Paulsen et al ldquoDefective skel-etogenesis with kidney stone formation in dwarf zebrafishmutant for trpm7rdquo Current Biology vol 15 no 7 pp 667ndash6712005

[136] LW Runnels L Yue andD E Clapham ldquoTRP-PLIK a bifunc-tional protein with kinase and ion channel activitiesrdquo Sciencevol 291 no 5506 pp 1043ndash1047 2001

[137] DH LamC EGrant andC EHill ldquoDifferential expression ofTRPM7 in rat hepatoma and embryonic and adult hepatocytesrdquoCanadian Journal of Physiology and Pharmacology vol 90 no4 pp 435ndash444 2012

[138] Y Zhu R Men M Wen X Hu X Liu and L Yang ldquoBlockageof TRPM7 channel induces hepatic stellate cell death throughendoplasmic reticulum stress-mediated apoptosisrdquo Life Sci-ences vol 94 no 1 pp 37ndash44 2014

[139] R Mishra V Rao R Ta N Shobeiri and C E Hill ldquoMg2+- andMgATP-inhibited and Ca2+calmodulin-sensitive TRPM7-likecurrent in hepatoma and hepatocytesrdquoThe American Journal ofPhysiologymdashGastrointestinal and Liver Physiology vol 297 no4 pp G687ndashG694 2009

[140] G J Barritt J Chen and G Y Rychkov ldquoCa2+-permeable chan-nels in the hepatocyte plasma membrane and their roles inhepatocyte physiologyrdquo Biochimica et Biophysica Acta (BBA)mdashMolecular Cell Research vol 1783 no 5 pp 651ndash672 2008

[141] L Fang C Huang X Meng et al ldquoTGF-1205731-elevated TRPM7channel regulates collagen expression in hepatic stellate cells viaTGF-1205731Smad pathwayrdquo Toxicology and Applied Pharmacologyvol 280 no 2 pp 335ndash344 2014

[142] L Fang S Zhan C Huang et al ldquoTRPM7 channel regulatesPDGF-BB-induced proliferation of hepatic stellate cells viaPI3K and ERK pathwaysrdquo Toxicology and Applied Pharmacol-ogy vol 272 no 3 pp 713ndash725 2013

[143] H Liu J Li Y Huang and C Huang ldquoInhibition of transientreceptor potential melastain 7 channel increases HSCs apopto-sis induced by TRAILrdquo Life Sciences vol 90 no 15-16 pp 612ndash618 2012

[144] Y Songa L Zhan M Yu et al ldquoTRPV4 channel inhibits TGF-1205731-induced proliferation of hepatic stellate cellsrdquoPLoSONE vol9 no 7 Article ID e101179 2014

[145] B H Bentzen S-P Olesen L C B Roslashnn andM Grunnet ldquoBKchannel activators and their therapeutic perspectivesrdquo Frontiersin Physiology vol 5 article 389 2014

[146] T Hoshi A Pantazis and R Olcese ldquoTransduction of voltageand Ca2+ signals by Slo1 BK channelsrdquo Physiology vol 28 no 3pp 172ndash189 2013

[147] A Hermann G Sitdikova and T Weiger ldquoOxidative stress andmaxi calcium-activated potassium (BK) channelsrdquo Biomolecu-les vol 5 no 3 pp 1870ndash1911 2015

[148] R Kohler B P Kaistha and H Wulff ldquoVascular KCa-channelsas therapeutic targets in hypertension and restenosis diseaserdquoExpert Opinion on Therapeutic Targets vol 14 no 2 pp 143ndash155 2010

[149] EAKo JHan I D Jung andW S Park ldquoPhysiological roles ofK+ channels in vascular smoothmuscle cellsrdquo Journal of SmoothMuscle Research vol 44 no 2 pp 65ndash81 2008

[150] A Rodrıguez-Vilarrupla M Graupera V Matei et al ldquoLarge-conductance calcium-activated potassium channels modulatevascular tone in experimental cirrhosisrdquoLiver International vol28 no 4 pp 566ndash573 2008

[151] X Gasull R Bataller P Gines et al ldquoHuman myofibroblastichepatic stellate cells express Ca2+-activated K+ channels thatmodulate the effects of endothelin-1 and nitric oxiderdquo Journalof Hepatology vol 35 no 6 pp 739ndash748 2001

[152] X D Tang M L Garcia S H Heinemann and T HoshildquoReactive oxygen species impair Slo1 BK channel function byaltering cysteine-mediated calcium sensingrdquo Nature Structuraland Molecular Biology vol 11 no 2 pp 171ndash178 2004

[153] T Stauber T Weinert and T J Jentsch ldquoCell biology and phys-iology of CLC chloride channels and transportersrdquoComprehen-sive Physiology vol 2 no 3 pp 1701ndash1744 2012

[154] G J M den Hartog S Qi J H O Van Tilburg G H Koekand A Bast ldquoSuperoxide anion radicals activate hepatic stellatecells after entry through chloride channels a new target in liverfibrosisrdquo European Journal of Pharmacology vol 724 no 1 pp140ndash144 2014

[155] B J Hawkins M Madesh C J Kirkpatrick and A B FisherldquoSuperoxide flux in endothelial cells via the chloride channel-3mediates intracellular signalingrdquo Molecular Biology of the Cellvol 18 no 6 pp 2002ndash2012 2007

[156] R E Lynch and I Fridovich ldquoPermeation of the erythrocytestroma by superoxide radicalrdquo The Journal of Biological Chem-istry vol 253 no 13 pp 4697ndash4699 1978

[157] Y Ikebuchi N Masumoto K Tasaka et al ldquoSuperoxideanion increases intracellular pH intracellular free calciumand arachidonate release in human amnion cellsrdquo Journal ofBiological Chemistry vol 266 no 20 pp 13233ndash13237 1991

[158] R Waldmann G Champigny F Bassilana C Heurteaux andM Lazdunski ldquoA proton-gated cation channel involved in acid-sensingrdquo Nature vol 386 no 6621 pp 173ndash177 1997

[159] Z-G Xiong X-P Chu and R P Simon ldquoCa2+-permeable acid-sensing ion channels and ischemic brain injuryrdquoThe Journal ofMembrane Biology vol 209 no 1 pp 59ndash68 2006

[160] F-R Wu C-X Pan C Rong et al ldquoInhibition of acid-sensingion channel 1a in hepatic stellate cells attenuates PDGF-inducedactivation of HSCs through MAPK pathwayrdquo Molecular andCellular Biochemistry vol 395 no 1-2 pp 199ndash209 2014

[161] A Arzumanyan H M G P V Reis and M A FeitelsonldquoPathogenic mechanisms in HBV- and HCV-associated hepa-tocellular carcinomardquo Nature Reviews Cancer vol 13 no 2 pp123ndash135 2013

[162] B Sun and M Karin ldquoInflammation and liver tumorigenesisrdquoFrontiers of Medicine vol 7 no 2 pp 242ndash254 2013

[163] X-W Yang J-W Liu R-C Zhang Q YinW-Z Shen and J-LYi ldquoInhibitory effects of blockage of intermediate conductanceCa2+-activated K+ channels on proliferation of hepatocellularcarcinoma cellsrdquo Journal of Huazhong University of Science andTechnology [Medical Sciences] vol 33 no 1 pp 86ndash89 2013


[164] C Freise M Ruehl D Seehofer J Hoyer and R Somasun-daram ldquoThe inhibitor of Ca2+-dependent K+ channels TRAM-34 blocks growth of hepatocellular carcinoma cells via down-regulation of estrogen receptor alphamRNAandnuclear factor-120581Brdquo Investigational New Drugs vol 31 no 2 pp 452ndash457 2013

[165] BMinguez V Tovar D Chiang A Villanueva and JM LlovetldquoPathogenesis of hepatocellular carcinoma and molecular ther-apiesrdquo Current Opinion in Gastroenterology vol 25 no 3 pp186ndash194 2009

[166] W Lai S Chen HWu et al ldquoPRL-3 promotes the proliferationof LoVo cells via the upregulation of KCNN4 channelsrdquo Oncol-ogy Reports vol 26 no 4 pp 909ndash917 2011

[167] M de Guadalupe Chavez-Lopez J I Perez-Carreon V Zuniga-Garcıa et al ldquoAstemizole-based anticancer therapy for hepato-cellular carcinoma (HCC) and Eag1 channels as potential early-stage markers of HCCrdquo Tumor Biology vol 36 no 8 pp 6149ndash6158 2015

[168] V Zuniga-Garcıa M de Guadalupe Chavez-Lopez V Quin-tanar-Jurado et al ldquoDifferential expression of ion channels andtransporters during hepatocellular carcinoma developmentrdquoDigestive Diseases and Sciences vol 60 no 8 pp 2373ndash23832015

[169] D Varela F Simon A Riveros F Joslashrgensen and A StutzinldquoNAD(P)H oxidase-derived H

2O2signals chloride channel

activation in cell volume regulation and cell proliferationrdquo TheJournal of Biological Chemistry vol 279 no 14 pp 13301ndash133042004

[170] D Varela F Simon P Olivero et al ldquoActivation of H2O2-

inducedVSORClminus currents inHTC cells require phospholipaseC1205741 phosphorylation and Ca2+ mobilisationrdquo Cellular Physiol-ogy and Biochemistry vol 20 no 6 pp 773ndash780 2007

[171] R-K Li J Zhang Y-H Zhang M-L Li M Wang and J-WTang ldquoChloride intracellular channel 1 is an important factor inthe lymphatic metastasis of hepatocarcinomardquo Biomedicine andPharmacotherapy vol 66 no 3 pp 167ndash172 2012

[172] X Wei J Li H Xie et al ldquoChloride intracellular channel 1participates in migration and invasion of hepatocellular car-cinoma by targeting maspinrdquo Journal of Gastroenterology andHepatology vol 30 no 1 pp 208ndash216 2015

[173] J Zhang M Li M Song et al ldquoClic1 plays a role in mousehepatocarcinoma via modulating Annexin A7 and Gelsolin invitro and in vivordquo Biomedicine and Pharmacotherapy vol 69pp 416ndash419 2015

[174] G Ermak and K J A Davies ldquoCalcium and oxidative stressfrom cell signaling to cell deathrdquo Molecular Immunology vol38 no 10 pp 713ndash721 2002

[175] W Huang C Lu Y Wu S Ouyang and Y Chen ldquoT-typecalcium channel antagonists mibefradil and NNC-55-0396inhibit cell proliferation and induce cell apoptosis in leukemiacell linesrdquo Journal of Experimental amp Clinical Cancer Researchvol 34 no 1 p 54 2015

[176] B Dziegielewska L S Gray and J Dziegielewski ldquoT-typecalcium channels blockers as new tools in cancer therapiesrdquoPflugers Archiv European Journal of Physiology vol 466 no 4pp 801ndash810 2014

[177] Y Li S Liu F Lu et al ldquoA role of functional T-type Ca2+channel in hepatocellular carcinoma cell proliferationrdquo Oncol-ogy Reports vol 22 no 5 pp 1229ndash1235 2009

[178] R Xie J Xu G Wen et al ldquoThe P2Y2 nucleotide receptormediates the proliferation and migration of human hepatocel-lular carcinoma cells induced by ATPrdquoThe Journal of BiologicalChemistry vol 289 no 27 pp 19137ndash19149 2014

[179] D Lavanchy ldquoThe global burden of hepatitis Crdquo Liver Interna-tional vol 29 supplement 1 pp 74ndash81 2009

[180] S L Chen and T R Morgan ldquoThe natural history of hepatitisC virus (HCV) infectionrdquo International Journal of MedicalSciences vol 3 no 2 pp 47ndash52 2006

[181] F V Chisari ldquoUnscrambling hepatitis C virus-host interac-tionsrdquo Nature vol 436 no 7053 pp 930ndash932 2005

[182] X Li and S A Weinman ldquoChloride channels and hepatocel-lular function prospects for molecular identificationrdquo AnnualReview of Physiology vol 64 pp 609ndash633 2002

[183] J Graf and D Haussinger ldquoIon transport in hepatocytesmechanisms and correlations to cell volume hormone actionsand metabolismrdquo Journal of Hepatology vol 24 supplement 1pp 53ndash77 1996

[184] A Girault and E Brochiero ldquoEvidence of K+ channel functionin epithelial cell migration proliferation and repairrdquo AmericanJournal of Physiology Cell Physiology vol 306 no 4 pp C307ndashC319 2014

[185] H A Kolb ldquoPotassium channels in excitable and non-excitablecellsrdquo Reviews of Physiology Biochemistry and Pharmacologyvol 115 pp 51ndash91 1990

[186] Y Amako Z Igloi J Mankouri et al ldquoHepatitis C virus NS5Ainhibits mixed lineage kinase 3 to block apoptosisrdquoThe Journalof Biological Chemistry vol 288 no 34 pp 24753ndash24763 2013

[187] Z Igloi B Mohl J D Lippiat M Harris J Mankouri andM SDiamond ldquoRequirement for chloride channel function duringthe hepatitis C virus life cyclerdquo Journal of Virology vol 89 no 7pp 4023ndash4029 2015

[188] M B Zeisel H Barth C Schuster and T F Baumert ldquoHepatitisC virus entry molecular mechanisms and targets for antiviraltherapyrdquo Frontiers in Bioscience vol 14 no 9 pp 3274ndash32852009

[189] J G Moreland A P Davis G Bailey W M Nauseef andF S Lamb ldquoAnion channels including ClC-3 are requiredfor normal neutrophil oxidative function phagocytosis andtransendothelial migrationrdquo Journal of Biological Chemistryvol 281 no 18 pp 12277ndash12288 2006

[190] SThevanantherH SunD Li et al ldquoExtracellularATP activatesc-jun N-terminal kinase signaling and cell cycle progression inhepatocytesrdquo Hepatology vol 39 no 2 pp 393ndash402 2004

[191] S Manzoor M Idrees J Ashraf et al ldquoIdentification ofionotrophic purinergic receptors in Huh-7 cells and theirresponse towards structural proteins of HCV genotype 3ardquoVirology Journal vol 8 article 431 2011

[192] V C Minguetti-Camara J Constantin F Suzuki-Kemmel-meier E L Ishii-Iwamoto and A Bracht ldquoHepatic heterogene-ity in the response to ATP studied in the bivascularly perfusedrat liverrdquo Molecular and Cellular Biochemistry vol 179 no 1-2pp 35ndash48 1998

[193] A MWaszkielewicz A Gunia N Szkaradek K Sloczynska SKrupinska andHMarona ldquoIon channels as drug targets in cen-tral nervous system disordersrdquo Current Medicinal Chemistryvol 20 no 10 pp 1241ndash1285 2013

[194] R Kohling ldquoVoltage-gated sodium channels in epilepsyrdquoEpilepsia vol 43 no 11 pp 1278ndash1295 2002

[195] W A Catterall A L Goldin and S G Waxman ldquoInternationalUnion of Pharmacology XLVII Nomenclature and structure-function relationships of voltage-gated sodium channelsrdquo Phar-macological Reviews vol 57 no 4 pp 397ndash409 2005


[196] K KamiyaM Kaneda T Sugawara et al ldquoA nonsensemutationof the sodium channel gene SCN2A in a patient with intractableepilepsy and mental declinerdquo Journal of Neuroscience vol 24no 11 pp 2690ndash2698 2004

[197] A M Rush S D Dib-Hajj and S G Waxman ldquoElectrophysi-ological properties of two axonal sodium channels Nav12 andNav16 expressed inmouse spinal sensory neuronesrdquo Journal ofPhysiology vol 564 part 3 pp 803ndash815 2005

[198] J D England L T Happel D G Kline et al ldquoSodium channelaccumulation in humans with painful neuromasrdquo Neurologyvol 47 no 1 pp 272ndash276 1996

[199] J G J Hoeijmakers C G Faber I S J Merkies and S GWaxman ldquoPainful peripheral neuropathy and sodium channelmutationsrdquo Neuroscience Letters vol 596 pp 51ndash59 2015

[200] E M Nagasako A L Oaklander and R H Dworkin ldquoCon-genital insensitivity to pain an updaterdquo Pain vol 101 no 3 pp213ndash219 2003

[201] S D Dib-Hajj A M Binshtok T R Cummins M F Jarvis TSamad and K Zimmermann ldquoVoltage-gated sodium channelsin pain states role in pathophysiology and targets for treat-mentrdquo Brain Research Reviews vol 60 no 1 pp 65ndash83 2009

[202] J Huang C Han M Estacion et al ldquoGain-of-function muta-tions in sodium channel Na(v)19 in painful neuropathyrdquo Brainvol 137 part 6 pp 1627ndash1642 2014

[203] H Ye S Jalini S Mylvaganam and P Carlen ldquoActivation oflarge-conductance Ca2+-activated K+ channels depresses basalsynaptic transmission in the hippocampal CA1 area in APP(sweind) TgCRND8 micerdquo Neurobiology of Aging vol 31 no4 pp 591ndash604 2010

[204] C Huang S Shen QMa et al ldquoBlockade of KCa31 amelioratesrenal fibrosis through the tgf-1205731smad pathway in diabeticmicerdquo Diabetes vol 62 no 8 pp 2923ndash2934 2013

[205] T T Chen T L Klassen A M Goldman C Marini R Guer-rini and J L Noebels ldquoNovel brain expression of ClC-1 chloridechannels and enrichment of CLCN1 variants in epilepsyrdquoNeurology vol 80 no 12 pp 1078ndash1085 2013

[206] C Jin Q-H Ye F-L Yuan et al ldquoInvolvement of acid-sensing ion channel 1120572 in hepatic carcinoma cell migration andinvasionrdquo Tumor Biology vol 36 no 6 pp 4309ndash4317 2015

[207] R-H Du J Tan N Yan et al ldquoKir62 knockout aggravateslipopolysaccharide-induced mouse liver injury via enhancingNLRP3 inflammasome activationrdquo Journal of Gastroenterologyvol 49 no 4 pp 727ndash736 2014

[208] E Kheradpezhouh L Ma A Morphett G J Barritt and G YRychkov ldquoTRPM2 channels mediate acetaminophen-inducedliver damagerdquo Proceedings of the National Academy of Sciencesof theUnited States of America vol 111 no 8 pp 3176ndash3181 2014

[209] M Adachi H Higuchi S Miura et al ldquoBax interacts withthe voltage-dependent anion channel and mediates ethanol-induced apoptosis in rat hepatocytesrdquo American Journal ofPhysiology Gastrointestinal and Liver Physiology vol 287 no3 pp G695ndashG705 2004

Submit your manuscripts athttpwwwhindawicom

Stem CellsInternational

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014


MEDIATORSINFLAMMATION

of


Behavioural Neurology

EndocrinologyInternational Journal of



Disease Markers


BioMed Research International

OncologyJournal of



Oxidative Medicine and Cellular Longevity


PPAR Research

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Immunology ResearchHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

ObesityJournal of



Computational and Mathematical Methods in Medicine

OphthalmologyJournal of


Diabetes ResearchJournal of



Research and TreatmentAIDS


Gastroenterology Research and Practice


Parkinsonrsquos Disease

Evidence-Based Complementary and Alternative Medicine

Volume 2014Hindawi Publishing Corporationhttpwwwhindawicom


diseases (Alzheimer Parkinson and others) [13ndash16] cellularaging [17] cardiovascular diseases (hypercholesterolaemiaheart failure hypertension myocardial infarction ische-miareperfusion injury and atherosclerosis) [18ndash20] andpathologies involving chronic inflammation [21] Howeverrecent studies have also associated oxidative stress with dia-betes mellitus [22] obesity [23] infectious diseases (HCV[24] malaria [25]) epilepsy [26] chronic pain [27 28] andeven preeclampsia [29]

2 Oxidative Stress and Ion Channels

Ion channels are multimeric proteins located in the plasmamembrane and inner cell compartments forming ion-select-ive pores that open or close in response to specific stimulisuch as membrane potential ligand-binding temperatureand mechanical stimuli [30] ROS and RNS can directlyinduce posttranslational modification of ion channels lead-ing to oxidation nitrosylation andor nitration of specificamino acid residues (sulfhydryl groups or disulfide linkagesinvolving cysteine residues) or indirectly modulate channelfunction by affecting the signaling pathways that controlgene transcription trafficking and turnover [31 32] Theassociation of ion channels in oxidative stress-related diseasesis reported mostly in cardiovascular [33 34] and neurode-generative illnesses [35ndash38] Multiple studies have reportedthe involvement of calcium [39ndash41] potassium [27 30 3642 43] sodium [34] and chloride channels [44 45] in thedevelopment of pathologies where oxidative stress plays amajor role (Table 1) Ion channels have been also suggestedto be associated with oxidative stress in the liver [32 46](Table 2) Next we will describe some of the most studiedplasma membrane and mitochondrial ion channels associ-ated with oxidative stress damage focusing primarily on theirpotential participation in liver pathological conditions

21 Participation of Mitochondrial Ion Channels in DifferentPathologies Generation of high energy molecules is carriedout by the mitochondria electron chain transport hence agreat amount of ROS is generated during thismetabolism [4748] Becausemitochondria are involved in the defense againstROS and its effects on intracellular redox equilibrium thestudy of mitochondria in pathological conditions associatedwith oxidative stress is fundamental [49 50]

There is a huge diversity of ion channels in both the outerand inner mitochondrial membrane (OMM IMM) Someof the ion channels located on the outer and inner mem-brane include voltage dependent anion channel (VDAC)Ca2+ uniporter permeability transition pore (PTP) calcium-activated potassium channels (KCa2+) ATP-sensitive potas-sium channels (KATP) and inner membrane anion channel(IMAC) [51] The field of mitochondrial ion channels hasrecently seen some progress through an integrative approachusing genetics physiology pharmacology and cell biologytools which have helped to elucidate the possible functionsof these channels [52] Some of these ion channels participatein several processes such as apoptosis [53 54] necrosisthermogenesis and volume regulation

The relevance of mitochondrial ion channel research isobserved in numerous studies that have demonstrated its par-ticipation in the development of pathological conditions likeneurodegenerative [35 55] and cardiac diseases [51 56ndash60]Even though mitochondrial dysfunction is associated withdifferent liver pathologies such as alcoholic liver diseases(ALD) [49 50 61 62] metabolic syndromes (insulin resis-tance) [63] and nonalcoholic fatty liver disease (NAFLD)[64] the participation of mitochondrial ion channels in theonset or development of oxidative stress-related liver diseaseshas not been fully explored

Nakagawa et al [65] reported the presence of mitochon-drial ATP-sensitive K+ (mitoKATP) channels in rat primaryhepatocytesThis study demonstrated that diazoxide (a selec-tive opener of mitoKATP channels) enhanced liver regener-ation by keeping a higher ATP content in the liver tissueThey concluded that diazoxide sustains the hepatocytesmitochondrial energetics promoting liver regeneration afterpartial hepatectomywhich is characterized by the presence ofoxidative stress Indeed potassium channel openers acting onmitochondria have proved to reduce cell damage observed inischemia For instance the effect of cromakalim and diazox-ide on cardioprotection against ischemia-reperfusion injuryhas been shown [66] Another study carried out by Shimizu etal [67] assessed the effect of diazoxide against brain damageafter middle cerebral artery occlusion (MCAO) in maleWistar rats The neurological score was improved in animalstreated with diazoxide in comparison with the control groupthe effects of diazoxide were prominent in the cerebral cortexAccordingly the protective effect was reversed with pretreat-ment of 5-hydroxydecanoate a selective blocker ofmitoKATPproving that selective opening of mitoKATP channel hasneuroprotective effects against ischemia-reperfusion injuryin the rat brain

Conductances reported for mitochondrial KATP channelsof different cell types are lower than those reported for plasmamembrane KATP variants under the same ionic condi-tions Moreover Szabo and Zoratti [52] mention that small-conductance Ca2+-activated K+ channels have conductancescompatible with the lower values reported for mitoKATPchannels Pharmacological approaches have their own com-plications due to the nonspecific targeting exhibited bysome mitoKATP inhibitors (5-hydroxydecanoate) and open-ers (such as diazoxide and cromakalim) which can also act onplasma membrane KATP channels according to some stud-ies Activators of KATP and SKCaIKCa (small-conductanceSKCa and intermediate-conductance (IKCa) calcium-acti-vated potassium channels) have structural similarities sug-gesting the possibility of a pharmacological crossover [52]

Interestingly mitochondria associated-endoplasmic reti-culum membranes (MAMs) which are important for Ca2+lipid and metabolite exchange were investigated by Arrudaet al [63] in the liverThey reported that the reorganization ofMAMs in a background of obesity resulted in mitochondrialCa2+ overload which compromised mitochondrial oxidativecapacity and increased oxidative stress Even though thisstudy did not address Ca2+ flux in mitochondria its resultsindicate that obesity drives an abnormal increase in MAMsformation along with an alteration in Ca2+ flux from the ER



inoxidatives

tress-rela

teddiseases

Type

Channel

Type

ofdysregulation

Oxidativ

estre

ss-rela

ted

disease

Mod

elAlteratio

npathop

hysio

logicaleffect

Ref

Na+

voltage-gated

sodium

channels

(VGSC

s)

Na v11

Miss

ense

mutation

Idiopathicepilepsy

Patie

nts

Increase

insodium

influ

xPatientssho

wvaria

bles

eizure

types

inclu

ding

absencemyoclon

icton


[2637

193ndash196]

Na v12

Miss

ense

mutation

Na v15


Coron

arymicrovascular

dysfu

nctio

nandisc

hemic

heartd

isease(IH

D)

Patie

ntspo

pulationstu

dyPo

lymorph


with

ahigherrisk

todevelopID

H

[34193

195]

Na v16

Largep

ersistent

sodium

current

Neurodegenerativ

edise

ases

Mou

semod

elTh

elarge

persistentcurrent

prod

uced

byNa v16

may

play

arolein

adam

aginginjury

cascadew

hencoexpressedwith

Na+

Ca+

exchangerindemyelin

ated

axon

s

[193195

197]

Na v17

Gain-of-fu

nctio

nmutation

Neuropathicpain

Patie

nts

Hyperexcitabilityof

neuron

sacuteo

rchron

icpain

[28195

198199]

Loss-of-fun

ctionmutation

Con


topain

Patie

nts

Indifferencetopain

[28195

198ndash200]

Na v18

Gain-of-fu

nctio

nmutation

Neuropathicpain

Patients

Mutations

contrib

utetopainfulp

eripheraln

europathyby

enhancem

ento

fthe

channelrsquosrespon

seto

depo

lariz

ationand

prod

uceh

yperexcitabilityin

DRG

neuron

s

[193195

201]

Na v19

Gain-of-fu

nctio

nmutation

Neuropathicpain

Patients

Gain-of-fu

nctio

nmutations

inthischannelare

suggestedto

contrib

utetopainauton

omicdysfu

nctio

nandaxon

aldegeneratio

nin

patientsw

ithperip

heraln

europathy

[193195

202]

Potassium

channels

K ir61


Coron

arymicrovascular

dysfu

nctio

nandisc

hemic

heartd

isease(IH

D)

Patients

Thep

olym

orph

ismrs5219

AAof

K ir62isassociated

with

aprotectiv

eeffectin

thed

evelo

pmento

fIHD

[34193]

K Ca11

Overactivation

Alzh

eimer

disease(AD)

Mou

semod


ROSin

mou

semod

elsof

ADsoBK

channelsaree

xtensiv

elyoxidized

[203]

K Ca31

Overexpression

Diabetic

neph

ropathy

Mou

semod

elandhu

man

tissue

Knockout

ofK C

a31redu

cesrenalfib

rosis

inam

ouse

mod

elof

diabeticneph

ropathy

[204]

Voltage-gated

chlorid

echannels(V

GClCs

)CL

IC1

Sing

lenu

cleotide

polymorph

isms

Idiopathicepilepsy

Patie

nts

Possiblecontrib

utionof

theldquo

skele

talrdquochlorid

echann

elClC-

1to

ther

egulationof

brainexcitability

[205]

Acid-sensin

gion

channels

ASIC1

aOverexpressed

HCC

Livertum

ortissues

and

SMMC-

7721

cells

Supp

ressionof


nby

RNAiatte

nuates

the

malignant

phenotypeo

fHCC

cells

[206]





[24]



[207]





[138]


4


[144]








[117 133]



[170]



[160]


proliferation[170]



[209]













0F1










5 Fibrosis



4-) induced






Quiescent hepatic


Activation


Kupffer cell


Fibrosis Fibrosis

120572-SMACol11205721

P2Y

TRPM7

TRPV4

P2Y

ASIC1a



PPADS A438970

Ru

PcTX1TGF-1205731

P2X7

2-APB Gd3+stress

uarr TRPM7

uarr ASIC1a

uarr TRPV4

uarr P2X7








4-treated rat





4






that the O2


2


2


2



4


6 Cancer





















7 Conclusions


Abbreviations















K+ channel


O2





Acknowledgment


References



































































































































































































































of






Disease Markers



OncologyJournal of





PPAR Research



Journal of

ObesityJournal of


















inoxidatives

tress-rela

teddiseases

Type

Channel

Type

ofdysregulation

Oxidativ

estre

ss-rela

ted

disease

Mod

elAlteratio

npathop

hysio

logicaleffect

Ref

Na+

voltage-gated

sodium

channels

(VGSC

s)

Na v11

Miss

ense

mutation

Idiopathicepilepsy

Patie

nts

Increase

insodium

influ

xPatientssho

wvaria

bles

eizure

types

inclu

ding

absencemyoclon

icton


[2637

193ndash196]

Na v12

Miss

ense

mutation

Na v15


Coron

arymicrovascular

dysfu

nctio

nandisc

hemic

heartd

isease(IH

D)

Patie

ntspo

pulationstu

dyPo

lymorph


with

ahigherrisk

todevelopID

H

[34193

195]

Na v16

Largep

ersistent

sodium

current

Neurodegenerativ

edise

ases

Mou

semod

elTh

elarge

persistentcurrent

prod

uced

byNa v16

may

play

arolein

adam

aginginjury

cascadew

hencoexpressedwith

Na+

Ca+

exchangerindemyelin

ated

axon

s

[193195

197]

Na v17

Gain-of-fu

nctio

nmutation

Neuropathicpain

Patie

nts

Hyperexcitabilityof

neuron

sacuteo

rchron

icpain

[28195

198199]

Loss-of-fun

ctionmutation

Con


topain

Patie

nts

Indifferencetopain

[28195

198ndash200]

Na v18

Gain-of-fu

nctio

nmutation

Neuropathicpain

Patients

Mutations

contrib

utetopainfulp

eripheraln

europathyby

enhancem

ento

fthe

channelrsquosrespon

seto

depo

lariz

ationand

prod

uceh

yperexcitabilityin

DRG

neuron

s

[193195

201]

Na v19

Gain-of-fu

nctio

nmutation

Neuropathicpain

Patients

Gain-of-fu

nctio

nmutations

inthischannelare

suggestedto

contrib

utetopainauton

omicdysfu

nctio

nandaxon

aldegeneratio

nin

patientsw

ithperip

heraln

europathy

[193195

202]

Potassium

channels

K ir61


Coron

arymicrovascular

dysfu

nctio

nandisc

hemic

heartd

isease(IH

D)

Patients

Thep

olym

orph

ismrs5219

AAof

K ir62isassociated

with

aprotectiv

eeffectin

thed

evelo

pmento

fIHD

[34193]

K Ca11

Overactivation

Alzh

eimer

disease(AD)

Mou

semod


ROSin

mou

semod

elsof

ADsoBK

channelsaree

xtensiv

elyoxidized

[203]

K Ca31

Overexpression

Diabetic

neph

ropathy

Mou

semod

elandhu

man

tissue

Knockout

ofK C

a31redu

cesrenalfib

rosis

inam

ouse

mod

elof

diabeticneph

ropathy

[204]

Voltage-gated

chlorid

echannels(V

GClCs

)CL

IC1

Sing

lenu

cleotide

polymorph

isms

Idiopathicepilepsy

Patie

nts

Possiblecontrib

utionof

theldquo

skele

talrdquochlorid

echann

elClC-

1to

ther

egulationof

brainexcitability

[205]

Acid-sensin

gion

channels

ASIC1

aOverexpressed

HCC

Livertum

ortissues

and

SMMC-

7721

cells

Supp

ressionof


nby

RNAiatte

nuates

the

malignant

phenotypeo

fHCC

cells

[206]





[24]



[207]





[138]


4


[144]








[117 133]



[170]



[160]


proliferation[170]



[209]













0F1










5 Fibrosis



4-) induced






Quiescent hepatic


Activation


Kupffer cell


Fibrosis Fibrosis

120572-SMACol11205721

P2Y

TRPM7

TRPV4

P2Y

ASIC1a



PPADS A438970

Ru

PcTX1TGF-1205731

P2X7

2-APB Gd3+stress

uarr TRPM7

uarr ASIC1a

uarr TRPV4

uarr P2X7








4-treated rat





4






that the O2


2


2


2



4


6 Cancer





















7 Conclusions


Abbreviations















K+ channel


O2





Acknowledgment


References



































































































































































































































of






Disease Markers



OncologyJournal of





PPAR Research



Journal of

ObesityJournal of




















[24]



[207]





[138]


4


[144]








[117 133]



[170]



[160]


proliferation[170]



[209]













0F1










5 Fibrosis



4-) induced






Quiescent hepatic


Activation


Kupffer cell


Fibrosis Fibrosis

120572-SMACol11205721

P2Y

TRPM7

TRPV4

P2Y

ASIC1a



PPADS A438970

Ru

PcTX1TGF-1205731

P2X7

2-APB Gd3+stress

uarr TRPM7

uarr ASIC1a

uarr TRPV4

uarr P2X7








4-treated rat





4






that the O2


2


2


2



4


6 Cancer





















7 Conclusions


Abbreviations















K+ channel


O2





Acknowledgment


References



































































































































































































































of






Disease Markers



OncologyJournal of





PPAR Research



Journal of

ObesityJournal of






















0F1










5 Fibrosis



4-) induced






Quiescent hepatic


Activation


Kupffer cell


Fibrosis Fibrosis

120572-SMACol11205721

P2Y

TRPM7

TRPV4

P2Y

ASIC1a



PPADS A438970

Ru

PcTX1TGF-1205731

P2X7

2-APB Gd3+stress

uarr TRPM7

uarr ASIC1a

uarr TRPV4

uarr P2X7








4-treated rat





4






that the O2


2


2


2



4


6 Cancer





















7 Conclusions


Abbreviations















K+ channel


O2





Acknowledgment


References



































































































































































































































of






Disease Markers



OncologyJournal of





PPAR Research



Journal of

ObesityJournal of






















5 Fibrosis



4-) induced






Quiescent hepatic


Activation


Kupffer cell


Fibrosis Fibrosis

120572-SMACol11205721

P2Y

TRPM7

TRPV4

P2Y

ASIC1a



PPADS A438970

Ru

PcTX1TGF-1205731

P2X7

2-APB Gd3+stress

uarr TRPM7

uarr ASIC1a

uarr TRPV4

uarr P2X7








4-treated rat





4






that the O2


2


2


2



4


6 Cancer





















7 Conclusions


Abbreviations















K+ channel


O2





Acknowledgment


References



































































































































































































































of






Disease Markers



OncologyJournal of





PPAR Research



Journal of

ObesityJournal of

















Quiescent hepatic


Activation


Kupffer cell


Fibrosis Fibrosis

120572-SMACol11205721

P2Y

TRPM7

TRPV4

P2Y

ASIC1a



PPADS A438970

Ru

PcTX1TGF-1205731

P2X7

2-APB Gd3+stress

uarr TRPM7

uarr ASIC1a

uarr TRPV4

uarr P2X7








4-treated rat





4






that the O2


2


2


2



4


6 Cancer





















7 Conclusions


Abbreviations















K+ channel


O2





Acknowledgment


References



































































































































































































































of






Disease Markers



OncologyJournal of





PPAR Research



Journal of

ObesityJournal of



















4






that the O2


2


2


2



4


6 Cancer





















7 Conclusions


Abbreviations















K+ channel


O2





Acknowledgment


References



































































































































































































































of






Disease Markers



OncologyJournal of





PPAR Research



Journal of

ObesityJournal of
































7 Conclusions


Abbreviations















K+ channel


O2





Acknowledgment


References



































































































































































































































of






Disease Markers



OncologyJournal of





PPAR Research



Journal of

ObesityJournal of

















O2





Acknowledgment


References



































































































































































































































of






Disease Markers



OncologyJournal of





PPAR Research



Journal of

ObesityJournal of






















































































































































































































of






Disease Markers



OncologyJournal of





PPAR Research



Journal of

ObesityJournal of
















review article ion channels and oxidative stress as a...

Documents