Abstract 13047: Differential Myocardial Proteomic Profiling in Mutant Myopalladin Knock-in Mice Models of Restrictive Cardiomyopathy
Background: Myopalladin (MYPN) gene mutations cause autosomal dominant cardiomyopathies in humans with variable penetrance. Knock-in MypnWT/Q529X mice recapitulate human restrictive cardiomyopathy (RCM) with cardiac fibrosis and diastolic dysfunction.
Objectives: The aim of this study was to identify RCM-associated cardiac protein abnormalities that contribute to the phenotypic diversity of mutant mice.
Methods: Studies were performed in 12 week old wild-type (WT), hetero- (MypnWT/Q529X), and homozygous (MypnQ529X) knock-in mice. Mice were phenotypically characterized by echocardiography and ECG, and 2-D gel electrophoresis and tandem mass spectrometry (MS) was applied on cardiac proteins. Selected proteins were cross-validated by immunohistochemistry and Western blotting.
Results: Systolic function and cardiac dimensions was normal among all groups, but Doppler echocardiography revealed early sings of diastolic dysfunction including increased E/A ratios, decreased LV end-diastolic and end-systolic volumes in MypnWT/Q529X only. Arrhythmias were also noted in MYPNWT/Q529X. Comparative proteomics analysis revealed 19 non-redundant protein changes in MypnQ529X vs MypnWT/Q529X, 10 proteins in MypnWT/Q529X vs WT and 8 proteins in MypnQ529X vs WT. The latter 8 overlapped with MypnQ529X vs MypnWT/Q529X group, showing concordant changes in WT and MypnQ529X groups. Specifically, Moes2, Vinc, Syne1, A1bg and Nrap were upregulated in WT and MypnQ529X compared to MypnWT/Q529X. WT and MypnQ529X displayed decrease in Myh6, Myoz2 and Fhl2. Only FGF9 was increased in both mutants. Stress proteins, Mlp/Csrp3 and Clpb, were upregulated in heterozygotes only. Upregulation of Capn8 and IL17 in MypnWT/Q529X indicated recruitment of proteolysis and cytokines. Differential phosphorylation of Myom2 and ERM (ezrin-radixin-moesin) family proteins were noted in MypnWT/Q529X vs homozygotes.
Conclusion: We demonstrate unfavorable protein expression changes at the onset of diastolic dysfunction before overt cardiac failure in MYPNWT/Q529X mice. The differential protein profiles showed strong association with cardiac disease in MypnWT/Q529X vs homozygous and control WT mice and may serve as early markers of restrictive cardiac remodeling.
- © 2013 by American Heart Association, Inc.