Frontiers in Cardiovascular Biology 2012 30.3 – 1.4.2012 London, UK The ubiquitin-proteasome system in hypertrophic cardiomyopathy Lucie Carrier Department of Experimental Pharmacology and Toxicology Cardiovascular Research Center, UKE, Hamburg, Germany Inserm U974-CNRS UMR7215, Paris, France NO CONFLICT OF INTEREST
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The ubiquitin-proteasome system in hypertrophic cardiomyopathy
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Frontiers in Cardiovascular Biology 201230.3 – 1.4.2012
London, UK
The ubiquitin-proteasome system in hypertrophic cardiomyopathy
Lucie Carrier
Department of Experimental Pharmacology and ToxicologyCardiovascular Research Center, UKE, Hamburg, Germany
Inserm U974-CNRS UMR7215, Paris, France
NO CONFLICT OF INTEREST
Presenter
Presentation Notes
14 min plus 3 min
Hypertrophic cardiomyopathy (HCM)
Elliott P et al., Eur Heart J 2008;Maron BJ et al., Circulation 2006
Schlossarek S et al., J Mol Cell Cardiol 2011 (review)
HCM : 19 genes and > 500 mutations
Cardiac myosin-binding protein C (cMyBP-C)
Schlossarek S et al., J Mol Cell Cardiol 2011 (review)
Human MYBPC3 mutation
13% of unrelated HCM patients
18% of myofilament-positive patients
30% of MYBPC3-positive patients
From Olivotto I et al., Mayo Clinic Proc 2008
G>A transition on the last nucleotide of exon 6
Human MYBPC3 mutationG>A transition on the last nucleotide of exon 6
Mearini G, Schlossarek S, Poggesi C, Marston et al., unpublished
Absent
Vignier N*, Schlossarek S* et al., Circ Res 2009
Absent
Knock-in of the human MYBPC3 mutation into the mouse genome : Mybpc3-targeted KI mice
Molecular mechanisms of Mybpc3 mutation
Mutantallele
Nonsense mRNAs Mutant proteins
??????
Molecular mechanisms of Mybpc3 mutation
Mutantallele
Nonsense mRNAs Mutant proteins
??????
Translation inhibitors: Emetine, CHXProteasome inhibitors: MG132, MG262, EpoxomicinIn cardiac myocytes or in vivo
Molecular mechanisms of Mybpc3 mutation
Mutantallele
Nonsense mRNAs Mutant proteins
Nonsense-mediatedmRNA decay Ubiquitin-proteasome system
Sarikas A et al., Cardiovasc Res 2005; Mearini G et al., Cardiovasc Res 2010;Vignier N*, Schlossarek S* et al., Circ Res 2009
Molecular mechanisms of Mybpc3 mutation
Mutantallele
Wild-typeallele
Wild-type proteinNonsense mRNAs Mutant proteins
Nonsense-mediatedmRNA decay Ubiquitin-proteasome system
Haploinsufficiency
LVH, diastolic dysfunction ?
Vignier N*, Schlossarek S* et al., Circ Res 2009
LVM/BW
WT Het KI0
2
4
6
8***
9 109
(mg/
g)
FAS
WT Het KI0
10
20
30
40
50
**
9 109(%
)
Fraysse B*, Weinberger F*, Bardswell S* et al., J Mol Cell Cardiol 2012, in press
Heterozygous KI mice do not develop LVH and systolic dysfunction
**p<0.01 and ***p<0.001 vs WT
Increased myofilament Ca2+ sensitivity
Fraysse B*, Weinberger F*, Bardswell S* et al., J Mol Cell Cardiol 2012, in press
7.0 6.5 6.0 5.5 5.0
0.0
0.2
0.4
0.6
0.8
1.0
WT Het
pCa
Rel
ativ
e Fo
rce
Het-KI WT
7.0 6.5 6.0 5.5 5.0
0.0
0.2
0.4
0.6
0.8
1.0
WT KIR
elat
ive
Forc
epCa
Hom-KI WT
pCa50: p<0.05 vs WT pCa50: p<0.05 vs WT
PWD
WTE
A
Het KI
TDIE‘
A‘
WT Het KI
E/A
WT Het KI0.0
0.5
1.0
1.5
2.0
9
***
109
**
E´/A´
WT Het KI0.0
0.5
1.0
1.5
2.0
9 109
*** ***
E/E´
WT Het KI0
10
20
30
40
50
9 109
**
Fraysse B*, Weinberger F*, Bardswell S* et al., J Mol Cell Cardiol 2012, in press
Diastolic dysfunction
*p<0.05, **p<0.01 and ***p<0.001 vs WT
Molecular mechanisms of Mybpc3 mutation
Mutantallele
Wild-typeallele
Wild-type proteinNonsense mRNAs Mutant proteins
Nonsense-mediatedmRNA decay Ubiquitin-proteasome system
Haploinsufficiency
Increased Ca2+ sensitivity and diastolic dysfunction
Fraysse B*, Weinberger F*, Bardswell S* et al., J Mol Cell Cardiol 2012, in press
Why do heterozygous mice not develop LVH?
LVM/BW
WT Het KI0
2
4
6
8***
9 109
(mg/
g)
Schlossarek S et al., J Muscle Res Cell Motil 2012
Adrenergic stress induced proteasome impairment in heterozygous Mybpc3-targeted KI mice
Wild-type and heterozygous mice
Combination of isoprenaline and phenylephrine (ISO/PE) or NaCl for 1 week
Ventricular-to-body weight ratio
0
1
2
3
4
5
6
#
8 87 8
*** ***
(mg/
g)
Chymotrypsin-like activity
0.0
0.2
0.4
0.6
0.8
1.0
1.2
8 7 8 8
#
***(AU
)
Mybpc3-knock-in mice (KI):G>A transition in exon 6