Abstract 17672: Myosin Binding Protein C Gene Mutation (S593Pfs*9) Induces Heart Failure and Reduced Ca Transient Amplitude in Zebrafish
Introduction: Mutations in the cardiac myosin-binding protein C (MYBPC3) gene have been implicated in over one third of hypertrophic cardiomyopathy (HCM) cases. These mutations have been reported to be associated with delayed expression of hypertrophy and a relatively good prognosis. However, we previously reported that a patients with a S593Pfs*9 mutation (a single base deletion of a thymidine residue at nucleotide 11645 in exon 18) in this gene deteriorated into the“end-stage” HCM, characterized by left ventricular systolic dysfunction, cavity dilation, and heart failure. This mutation causes a truncated MYBPC3. The precise functional and pathological consequences of this mutation are not fully characterized. The aim of this study was to recapitulate the S593Pfs*9 mutation in the zebrafish to define the pathologic mechanisms.
Methods: We used the CRISPR/Cas9 system to generate a genocopy of the S593Pfs*9 with a specific guide RNA injected with Cas9 into one-cell stage embryos.
Results: Gross morphological examination of the mutants showed a smaller ventricle and pericardial edema compared with controls. There were significant reductions in heart rate (125 +/- 31 vs 148 +/- 9 /min), end-diastolic volume (EDV) (0.41 +/- 0.16 vs 0.72 +/- 0.18 nl), end-systolic volume (ESV) (0.24 +/- 0.08 vs 0.36 +/- 0.13 nl), stroke volume (SV) (0.16 +/- 0.12 vs 0.36 +/- 0.09 nl) in mutants compared with control embryos at 48 hours post fertilization (hpf). In addition, the calcium transient amplitude (0.17 +/- 0.02 vs 0.23 +/- 0.02 ratio units) was also significantly reduced in the mutant hearts compared with the control hearts at 48 hpf.
Conclusions: Our data demonstrate that the S593Pfs*9 mutants exhibit reduced EDV, ESV, and SV and define early abnormalities of Ca2+ handling that may drive the development of heart failure at later stages. This model will allow the mechanistic dissection of MYBPC-associated heart failure and enable chemical screens for novel drugs.
Author Disclosures: A. Ogimoto: None. G. Musso: None. A.A. Werdich: None. D.A. White: None. M.E. Beerens: None. P. Sips: None. S. Kapur: None. M.L. Burch: None. L.M. Flores: None. J. Higaki: None. C.A. MacRae: None.
- © 2015 by American Heart Association, Inc.