no slide title · rhonda bassel-duby, ph.d. associate professor of molecular biology. diagram of...
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STARSMini-Symposium
Skeletal Muscle:Development, Adaptation & Disease
“Gain Without Pain”
Rhonda Bassel-Duby, Ph.D.Associate Professor of Molecular Biology
Diagram of Skeletal Muscle
Myoglobin Immunohistochemistry
Subtypes of Skeletal Myofibers
Type I (slow)Type I (slow) Type Type IIaIIa Type Type IIb IIb (fast)(fast)
white, glycolyticfatigue rapidlyrapid force developmentinsulin-resistant
red, oxidativefatigue-resistantslow contractioninsulin-sensitive
endurance training, nerve stimulation
inactivity, disease, hypogravity
Establishing Myofiber SpecializationPreprogramming of myoblasts
Pattern imposed by motor nerve
tonic
phasic
Cross-innervation Switches Fiber Types
Buller et al.,19 60
Electrical Stimulation Model
unstimulated stimulated
Molecular Marker of Muscle Plasticity
myoglobin
Electrical Signals Alter Intracellular Calcium
time (min)60 120 180 240 3000
0
0.2
0.4
[Ca
2+] i(µM
)
time (sec)
01 2 3 4 5 60
[Ca
2+] i(µM
)0.5
1.0
200 ms
10 Hz continuous 100 Hz intermittent
0.5mv
EMG
Type I fibers Type II fibers
Genetic Reprogramming of Skeletal Muscleneural activity
Ca2+
GSK3
MCIP
HDAC
Myofiber specialization (fiber type)
NFAT
calcineurin
PGC-1MEF2
CaMK
Genetic Manipulation of Signal Transduction Pathways in Muscle
Voluntary Running Cages
Voluntary Wheel Running Enhances Muscle Oxidative Capacity
Sedentary 4 wk run
Genetic Reprogramming of Skeletal Muscleneural activity
Myofiber specialization (fiber type)
NFAT
calcineurin
Ca2+
Genetic Manipulation of Signal Transduction Pathways in Muscle
Calcineurin Promotes Slow Fiber Transformation
MCK 4.8 kb calcineurin hGH
MCK-CnA*Wild-type
Slow myosin ATPase(gastrocnemius)
Naya et al. J Biol Chem, 1999.
Genetic Reprogramming of Skeletal Muscleneural activity
Ca2+
MEF2
CaMK
Myofiber specialization (fiber type)
Expression of CaMKIV* in Skeletal Muscle
MCK 4.8 kb hGHCaMKIV*
CaMKIV*
CaMKIV-brainCaMKIV-testis
brai
nhe
art
lung
liver
stom
ach
kidn
eysp
leen
test
issk
. mus
cle
CaMKIV*
tubulin
sole
usPL
AED
LW
V
sol e
usPL
AED
LW
V
Wild-type
MCK-CaMK
CaMK Promotes Slow Fibers Transformation
Wild-type
MCK-CaMK
Wu et al. Science, 2002.
CaMK Stimulates Mitochondrial Biogenesis
MC
K-C
aMK
Wild
-type
Wu et al. Science, 2002.
MCK-CaMK Muscle Shows Improved Function
Wu et al. Science, 2002.
Genetic Reprogramming of Skeletal Muscleneural activity
Myofiber specialization (fiber type)
NFAT
calcineurin
PGC-1MEF2
CaMK
Ca2+
PGC-1α Promotes Slow Fiber Transformation
MCK 4.8 kb hGHPGC-1α WT TgSol Pl Sol Pl
PGC-1α
* *
WT Tg
WT Tg
myoglobin
Tn I-slow
cytochrome c
tubulin
Hind limb Soleus/GastrocnemiusWT Tg
Lin et al. Nature, 2002.
PGC-1α Promotes Slow Fiber Transformation
Wild-type
MCK-PGC-1
metachromatic stain anti-myosin (slow)
MCK-PGC-1 Muscle is More Resistant to Fatigue
WT
Stim
ulat
ion
time
(min
)
2
4
6
8
10
12
14
16
P<0.01
MCK-PGC-1αLin et al. Nature, 2002.
Genetic Reprogramming of Skeletal Muscleneural activity
Ca2+
Myofiber specialization (fiber type)
NFAT
calcineurin
PGC-1MEF2
CaMK
Calcineurin Enhances Insulin-StimulatedGlucose Transport in Muscle
0
5
10
15
2deo
xygl
ucos
e U
ptak
e(n
mol
/mg/
20 m
in)
Wild-typeEDL
MCK-CnA*EDL
insulininsulin
-+
Ryder et al. JBC, 2003
Calcineuirn Modulates Insulin-Stimulated Glucose Uptake in Muscle
IRS1
GLUT4 Pool
GlucoseInsulin
PI3-K
AktEnhanced
Glucose UptakeCalcineurin
Neural activity
[Ca2+ ]
Modified Gene Program
Genetic Reprogramming of Skeletal Muscleneural activity
Ca2+
GSK3
MCIP
HDAC
Myofiber specialization (fiber type)
NFAT
calcineurin
PGC-1MEF2
CaMK
Skeletal Muscle Regenerates
satellite cells
Muscle Regeneration
quiescent satellite cells proliferating satellite cells
quiescent satellite cells
Growing Muscle on Synthetic Fibers
Acknowledgements
Hai Wu Daniel GarryJoseph GarciaFritz Thurmond
Sandy WilliamsEric Olson
Jim RichardsonJohn Shelton
Bruce SpiegelmanJiandie LinHarvard Medical School
Jeffrey Ryder
Frank NayaEva ChinDarrell NeuferElizabeth Cronin Jim Stull
George Ordway
Karolinska, Sweden