Abstract 17002: Deficient cMyBP-C Protein Expression During Early Cardiac Differentiation Underlies Human Hypertrophic Cardiomyopathy Cellular Phenotypes in Disease Specific Human Es Cell Derived Cardiomyocytes

• Published in: Circulation (New York, N.Y.) N.Y.), 2016-11, Vol.134 (Suppl_1 Suppl 1), p.A17002-A17002
• Main Authors: Monteiro da Rocha, Andre, Guerrero-Serna, Guadalupe, Helms, Adam, Luzod, Carly, Mironov, Sergey, Russell, Mark, Jalife, Jose, Day, Sharlene M, Smith, Gary D, Herron, Todd J
• Format: Article
• Language: English
• ISSN: 0009-7322; 1524-4539

IntroductionMutations of cardiac sarcomere genes have been identified to cause hypertrophic cardiomyopathy (HCM), but the molecular mechanisms that lead to cardiomyocyte hypertrophy and risk for sudden death are uncertain.HypothesisStem cell (hESC)-derived cardiomyocytes (hESC-CMs) are a useful tool to study human HCM disease mechanisms at play during human cardiac differentiation in vitro.MethodsControl or HCM specific hESC-CMs were generated using monolayer and cytokine based differentiation. Cardiomyocytes were stained against α-actinin for determination of sarcomere organization and cell size. Additionally, samples were collected during the time course of cardiac differentiation for protein expression analysis. Differentiated cardiomyocytes were purified with SIRPα-2 mediated magnetic separation for generation of cardiac monolayers for electrophysiological phenotype analysis.ResultsHCM-specific hESC-CMs displayed hallmark aspects HCM including sarcomere/myocyte disarray (Figure1a), hypertrophy (Figure 1b) and impaired calcium impulse propagation (Figure 1c). During cardiomyocyte differentiation, expression of MYBPC3 in HCM ESC-CMs temporally lagged behind control hESC-CMs but by day 30 post differentiation was similar to control ESC-CMs (Figure 2a). Gene transfer of full-length MYBPC3 during early cardiac differentiation (Figure 2b) prevented sarcomere disarray (Figure 2c), hypertrophy (Figure 2d) and improved calcium impulse propagation in HCM hESC-CMs (Figure 2e).ConclusionsThese findings point to the critical role of MYBPC3 during sarcomere assembly in cardiac myocyte differentiation and suggest developmental influences of MYBPC3 truncating mutations on the mature hypertrophic phenotype.