molecular cell biology (bio 5068) · (3) cystogenesis causes kidney fibrosis and scarring bergmann...

Ciliopathies and Centrosomopathies

Molecular Cell Biology (Bio 5068)

@MahjoubLab

Moe R. Mahjoub Department of Medicine (Nephrology), Cell Biology & Physiology

Washington University in St Louis

Human Ciliopathies: Diseases caused by defective ciliary function

Sjogren

Leber's congenital amaurosis

Senior-Loken

Polycystic kidney disorder

Sensenbrenner syndrome

von Hippel-Lindau

Short rib polydactyly disorders

Joubert syndrome

Nephronophthisis

Meckel-Gruber

Alstrom

Bardet-Biedl

Primary cilia dyskinesia

eye

kidney

liver

skeletal

CNS

laterality

obesity

respiratorytract

Image: Susan Dutcher

Outline:

!  Motile Ciliopathies •  Left-Right asymmetry •  Primary Ciliary Dyskinesia

!  Sensory Ciliopathies •  Polycystic Kidney Disease •  Retinal degeneration

!  Centrosomopathies •  Microcephaly

•  Cancer

Reiter and Leroux, Nature Reviews – MCB (2018)

Nodal cilia, a rare type of motile cilium…

Symmetry breaking by nodal cilia-mediated flow

D. Grimes, Development (2019)

Symmetry breaking by nodal cilia-mediated flow

Yaun et al, Current Biology (2015)

Zebrafish L-R organizer

Nodal cilia dysfunction causes organ laterality defects

•  Rare congenital disease – affects roughly 1 in 10,000 live births

•  Inheritance: either autosomal recessive (most commonly), autosomal dominant, or X-linked.

•  Mutations can be in ciliary genes (motility or signaling), or in morphogenesis pathways

•  Patients with situs inversus totalis can live normally with few symptoms

•  Heterotaxy syndrome (situs ambiguus) – associated with heart, lung, and other organ defects that can be fatal

Diseases of the airway: Primary Ciliary Dyskinesia (PCD)

Ciliated cells

Secretory cells (mucus, surfactant)

The Mucociliary Escalator

https://kids.frontiersin.org

J. Whitsett, Annals of the American Thoracic Society (2018)

Primary Ciliary Dyskinesia (PCD)

https://kids.frontiersin.org Zhou-Suckow et al, Cell and Tissue Research (2017)

Primary Ciliary Dyskinesia (PCD)

https://kids.frontiersin.org Mirra et al, Frontiers in Pediatrics (2017)

Primary Ciliary Dyskinesia (PCD)

Mirra et al, Frontiers in Pediatrics (2017)

•  Rare, inherited, autosomal recessive (mostly), although example of X-linked inheritance exists

•  Congenital disease – 1 in 20,000 live births

•  At least 40 genes identified so far (but almost half the genes are unknown)

•  Mutations mostly disrupt ciliary dynein motor preassembly and trafficking into cilia

•  ~50% of patients also display organ laterality defects

Mutations in PCD and impact on cilia ultrastructure

Mirra et al, Frontiers in Pediatrics (2017) Horani and Ferkol, Chest (2018)

Treatment regiments in PCD patients

Guan et al, Current Allergy and Asthma Reports (2018)

In addition to this inherited genetic disease, there are also acquired cilia-associated airway diseases (e.g. COPD, asthma)

Outline:

!  Motile Ciliopathies •  Left-Right asymmetry •  Primary Ciliary Dyskinesia

!  Sensory Ciliopathies •  Polycystic Kidney Disease •  Retinal degeneration

!  Centrosomopathies •  Microcephaly

•  Cancer

Reiter and Leroux, Nature Reviews – MCB (2018)

Sensory Ciliopathies: Polycystic Kidney Disease

•  Most common ciliopathy – 1 in 400 people

•  Most common inherited monogenic kidney disease

•  Autosomal Dominant (ADPKD) •  Mutations in 2 genes - PKD1 (85%) and PKD2 (10%)

•  Slow, degenerative disease

•  Results in end-stage kidney failure in the 50-60’s

•  Autosomal Recessive (ARPKD) •  Rare (1 in 20,000)

•  Mutations in a single gene – PKHD1

•  Rapid onset

•  Both ADPKD and ARPKD are associated with extra-renal manifestations (e.g. liver cysts)

Mechanosensory role of the primary cilium in nephrons

O’Connor et al, Cilia (2013)

Mechanosensory role of the primary cilium in nephrons

Molecular mechanisms of renal cystogenesis

Bergmann et al, Nat. Rev. Dis. Primers (2018)

Cellular mechanisms of renal cystogenesis

Bergmann et al, Nat. Rev. Dis. Primers (2018)

(1)

(2)

(3)

Cystogenesis causes kidney fibrosis and scarring

Bergmann et al, Nat. Rev. Dis. Primers (2018)

Xue and Mei, Renal Fibrosis: Mechanisms and Therapies (2019)

Defective ciliary

signaling

Sensory Ciliopathies: Retinal Degeneration

The outer segment of photoreceptor cells is a highly

modified sensory cilium

Mechanism of ciliary assembly and protein trafficking in photoreceptors

May-Simera et al, Progress in Retinal and Eye Research (2017)

Mechanism of ciliary assembly and protein trafficking in photoreceptors

Nemet et al, Progress in Molecular Biology and Translational Science (2015)

Patho-mechanism of retinal degeneration

•  Mutations in ~250 genes identified so far

•  Most common inherited disease is Retinitis pigmentosa (affects 1 in 3000 people)

•  Symptoms begin in the 20’s - patients typically begin to develop night blindness, which turns into tunnel vision and ultimately blindness.

Mutations disrupt: •  Centriole formation (genes essential for biogenesis) •  Centriole appendages (docking of mother centriole

disrupted) •  IFT genes (trafficking into cilia abnormal) •  Transition zone (aberrant ciliary protein composition)

Patho-mechanism of retinal degeneration

May-Simera et al, Progress in Retinal and Eye Research (2017)

Outline:

!  Motile Ciliopathies •  Left-Right asymmetry •  Primary Ciliary Dyskinesia

!  Sensory Ciliopathies •  Polycystic Kidney Disease •  Retinal degeneration

!  Centrosomopathies •  Microcephaly

•  Cancer

Reiter and Leroux, Nature Reviews – MCB (2018)

Autosomal Recessive Primary Microcephaly

•  Rare - affects 1 in 10,000-250,000 people •  The majority (80%) of mutations are in centrosome genes

Mutations impact: •  Centriole formation (genes essential for biogenesis) •  Pericentriolar material (PCM) – microtubule organization •  Mitosis

Cellular mechanism of pathogenesis

•  Centrosomes control fate decisions during asymmetric cell division

•  Mutations in centrosome genes disrupt this process

“Older” centrosome “Younger” centrosome

Pelletier and Yamashita (2012)

Cellular mechanism of pathogenesis

•  Neural progenitor cells (NPCs) undergo a series of symmetric proliferative divisions during early neurogenesis to expand the NPC pool.

•  These cells then switch to an asymmetric mode of division that

generates neurons and maintains the NPC pool throughout the later stages of neurogenesis (top).

•  Defects in centrosome-related microcephaly (CRM) genes can

disrupt neurogenic divisions, resulting in loss of NPCs by: o  premature differentiation due to spindle mis-orientation o  cell cycle delays (mitotic)

o  activation of apoptotic pathways due to failure to satisfy the spindle assembly checkpoint

o  Chromosome missegregation and aneuploidy .

•  Collectively, these defects result in reduction of the abundance of neurons, causing smaller brain size

O’Neill et al, Molecular Biology of the Cell (2018)

Abnormal centrosome biogenesis and cancer

Overduplication Cytokinesis failure

Cell fusion Viral infection

Boveri, 1914: extra centrosomes drive genome instability in tumors

Galeotti, 1896

Abnormal centrosome biogenesis and cancer

Cosensa and Kramer, Chromosome Research, 2015

Centrosome clustering helps cancer cells survive

P30 P45 P75

Milunovic-Jevtic et al, 2016

Centrosome Clustering

Centrosome clustering helps cancer cells survive

Cosensa and Kramer, Chromosome Research, 2015

Centrosome-dependent mechanism of tumor formation

Arnandis et al, Dev Cell, 2018

Centrosome-dependent mechanism of tumor formation

•  The majority of solid tumors (>80%) contain cells with extra centrosomes

•  But, these cells only make up a small fraction of the tumor population (between 10-20% of cells).

•  How can a small population of cells with abnormal centrosome number drive tumor growth?

•  Cause genomic instability in daughter cells after cell division

•  Induce proliferation of neighboring cells via paracrine signaling

•  Promote invasivness by increasing microtubule number emanating from the centrosome

Arnandis et al, Dev Cell, 2018

Nigg and Holland, Nature Reviews – Molecular Cell Biology (2018)

P30 P45 P75

Milunovic-Jevtic et al, 2018

Genome instability Ciliary defects Enhanced secretion

Targeting cells with centrosome amplification as a therapeutic strategy

Inhibition of centrosome clustering in vitro

P30 P45 P75

Mariappan et al, EMBO Reports (2018)

Inhibition of centrosome clustering in vivo

P30 P45 P75

Mariappan et al, EMBO Reports (2018)

Thank you!

Questions?

Contact me: mmahjoub@wustl.edu