“The Ciliopathies: Recent
advances"
Phil Beales
[email protected]
Molecular Medicine Unit, Institute of Child Health
and Great Ormond Street Hospital for Children,
University College London
Aims



I. Structure and function of cilia
II. Advances in ciliopathy research
III. Potential for therapy
Antony van Leeuwenhoek (1632-1723)
"And though I must have
seen quite 20 of these little
animals on their long tails
alongside one another very
gently moving, with
outstretched bodies and
straightened-out tails; yet in
an instant, as it were, they
pulled their bodies and their
tails together, and no sooner
had they contracted their
bodies and tails, than they
began to stick their tails out
again very leisurely, and
stayed thus some time
continuing their gentle
motion: which sight I found
mightily diverting.“
Letter to Royal Society of
London - December 25, 1702
What is the evidence for cilia in
disease?



Fluid movement
Vestigial remnants
Sensory role:
–
–
–

Polycystic kidneys
Photoreceptors
L-R assymetry
Signalling
Cilia and signalling
Hedgehog limbs defects
Adapted from Goetz and Anderson Nat Rev Genet. 2010
What is the evidence for cilia in
disease?



Fluid movement
Vestigial remnants
Sensory role:
–
–
–

Polycystic kidneys
Photoreceptors
L-R assymetry
Signalling
Cystic renal disease
Wildtype
Orpk/Polaris
Pazour G J et al. J Cell Biol 2000;151:709-718
Ciliated sensory cells
Left-right asymmetry
Courtesy N. Hirokawa
Situs anomalies
What is a ciliopathy?

I. Motile (9+2)
–

Kartagener syndrome (PCD)– (e.g. DNAH5, DNAI1,
DNAH11, TXNDC3 )
II. Non-motile (9+0)
–
–
–
–
–
–
–
–
–
Alstrom syndrome
Bardet-Biedl syndrome
Jeune syndrome
Joubert syndrome
Meckel syndrome
Nephronophthisis (NPHP)/Senior-Loken
Ellis van Creveld
Oral Facial Digital Type 1 (OFD1) (X-linked)
Polycystic kidney disease (ARPKD/ADPKD)
Primary Ciliary Dyskinesia



Baillie first described
situs inversus in 1793
Kartagener (1933) triad - sinusitis,
bronchiectasis, and
situs inversus
Cilia immotility in
infertile males –
Afzelius (1976)
cilia beating
Cilia lining the airways provide a motile
surface to clear away bacteria from our
airways
7 PCD genes are essential
components of cilia structure
2 PCD genes get the other
proteins to their correct
location in cilia
Courtesy of Hannah Mitchison
PCD genes
LRRC50
2009 KTU
2009
α
Outer dynein arm
(Chlamydomonas)
DC1
8
IC1
6
DC3
DNAI2
DNAI1
2008
1999
TXNDC3
2007
DNAH5
DNAH11
2002
2002
RSPH9, RSPH4A
2009
9 genes causing 17-38% disease
Courtesy of Hannah Mitchison
Bardet-Biedl Syndrome






Retinal Degeneration
Cognitive impairment
Obesity
Polydactyly
Hypogenitalism/genital
malformation
Renal
dysfunction/malformation
BBS genes
Locus
BBS1
BBS2
BBS3/ARL6
BBS4
BBS5
BBS6/MKKS
BBS7
BBS8
BBS9
BBS10
BBS11/TRIM32
BBS12
BBS13+
Chromosome
11q13
16q21
3p13
15q23
2q31
20p12
4q27
14q32.1
7p14
12q21
9q33.1
4q27
-
Function
Novel gene
Novel gene
ARL6
TPRs/OGT
Novel gene
Chaperone
Novel gene
PilF/TPRs
PTH-B1
Chaperone
TRIM32
Chaperone
MKS1, MKS3,
Cep290
BBS8 first clue to cilia
dysfunction
TTC8
TTC8
TTC8
Ansley et al Nature 2003
C. elegans
Adult worm has 959 cells
302 are neuronal
60 of these are ciliated
Genes for osmolarity and chemotaxis are
expressed exclusively in these 60 ciliated
cells
osm-1, osm-5, osm-6, che-2
bbs8
BBS8
Ac. tubulin
Merge + DAPI
Ciliary Interactome
Meckel
BBS7
BBS2
BBS1
BBS4
BBS6
BBS9
JS
PCM1
BBS8
BBS5
AS
YTH
Proteome
NPHP



GM reduction in ant
temporal lobes, olfactory
bulbs
Hippocampal volume
Smo, Ift88 and Fantom
knockouts – cilia required for
postnatal neural stem cell
proliferation via the Sonic
Hedgehog pathway
Alström syndrome

Cone-rod dystrophy
Early onset obesity
Type 2 diabetes mellitus
Neuro-sensory hearing loss
Cardiomyopathy
Short
Male hypogonadism
AR

ALMS1










Adult Alström
cardiomyopathy - fibrotic
process causing
impairment of both
ventricles
Serial cardiac MRI
advocated
Cause of fibrosis?
Alström and hearing loss


Alms1 localises to
basal body of
cochlear hair cells
Alms1 required for
normal cell pattern
likely accounting for
hearing loss
Jagger et al. 2010 HMG (AOP)
102 likely ciliopathies
14 proven
Jeune syndrome (asphyxiating
thoracic dystrophy)

Rare autosomal recessive chondrodysplasia
Often leads to death in infancy - severely
constricted thoracic cage (short ribs) and respiratory
insufficiency
Metaphyseal abnormalities/short long bones
Liver (fibrocystic), pancreatic (fibrosis) involvement
Post-axial polydactyly
Renal cysts
Retinal degeneration

Multiple loci mapped (15q13, 3q25)






wt
H105Q
JATD-03
JATD-02
JATD-01
L549del
wt
L549del
A701P
A701P
wt
Tetrahymena thermophila
GFPift80
Courtesy Mark Winey
wild-type
ift80 depletion
Acetylated tubulin (cilia)
Centrin (basal bodies)
Blacque et al. Frontiers in Bioscience 13, 2633-2652
IFT46
IFT88
IFT80
IFT172
IFT140
IFT122
IFT52
Adapted from Blacque et al. Frontiers in Bioscience 13, 2633-2652
American Journal of Human Genetics 84, 706–711, 2009
American Journal of Human Genetics 84, 542–549, 2009
Polycystic kidney disease

Autosomal recessive
PKD (ARPKD)
–

1 in 10,000
Autosomal dominant
PKD (ADPKD)
–
1 in 800
mTOR signalling in PKD




mTOR inhibitors reduce
cyst formation
mTORC1 activity
contributes to ADPKD
PC1 suppresses mTOR
activity
TSC proteins regulate
ciliary length (but no
evidence for vv)
Latest human trials - rapamycin

3 placebo-controlled trials
Different outcomes
SIRENA (Sirolimus) study – inhibits cyst
growth and >parenchymal volume
Swiss ADPKD study – no change in TKV or
eGFR
Everolimus study – slowed increase in TKV

May stabilise renal function if given early




Treating ciliopathies



Gene therapy – disadvantage in multisystem
disorders
Exon skipping – gentamicin/PTC124
Pharmacological interventions
a.
b.
–
–
Pathway targetted approach
Library screen to rescue individual phenotypes
Small molecules – prolonged development period
Approved drugs – safety, toxicity, side-effects
Zebrafish kidney
Drummond et al 1998
Zebrafish morphants develop
pronephric cysts
Rapamycin reduces renal cysts &
recovers function
control
bbs4 MO
bbs6 MO
bbs6 MO + Rapa
bbs8 MO
bbs8 MO + Rapa
ift80 MO
ift80 MO + Rapa
Rescue of kidney cyst
Size of kidney
200000
180000
160000
Kidney surface area (um2)
140000
120000
100000
80000
60000
40000
20000
0
control
0nM Rapa
(n=8)
ift80 MO
0nM Rapa
(n=22)
ift80 MO
10nM Rapa
(n=20)
ift80 MO
100nM Rapa
(n=12)
bbs6 MO 0nM
Rapa
(n=10)
bbs6 MO
100nM Rapa
(n=4)
bbs8 MO 0nM
Rapa
(n=11)
bbs8 MO
100nM Rapa
(n=8)
Tobin and Beales Ped Nephr 2006
Ciliopathies
Summary





Ciliopathies – diverse overlapping conditions
Collectively common
Share fundamental cellular defects but specific
differences
Many more ......
Therapeutic approaches – reprofiling promising