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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)
