Altered myocyte contractility and calcium homeostasis in alpha-myosin heavy chain point mutations linked to familial dilated cardiomyopathy

作者：Klos Matthew; Mundada Lakshmi; Banerjee Indroneal; Morgenstern Sherry; Myers Stephanie; Leone Michael; Kleid Mark; Herron Todd; Devaney Eric

来源：Archives of Biochemistry and Biophysics, 2017, 615: 53-60.

DOI：10.1016/j.abb.2016.12.007

• Alpha myosin heavy chain (alpha MHC)
• Beta myosin heavy chain (beta MHC)
• Hypertrophic cardiomyopathy (HCM)
• Dilated cardiomyopathy (DCM)
• Isoproterenol (Iso)

Mutations in the human cardiac motor protein beta-myosin heavy chain (beta MHC) have been long recognized as a cause of familial hypertrophic cardiomyopathy. Recently, mutations (P830L and A1004S) in the less abundant but faster isoform alpha-myosin heavy chain (alpha MHC) have been linked to dilated cardiomyopathy (DCM). In this study, we sought to determine the cellular contractile phenotype associated with these point mutations. Ventricular myocytes were isolated from 2 month male Sprague Dawley rats. Cells were cultured in M199 media and infected with recombinant adenovirus containing the P830L or the A1004S mutant human aMHC at a MOI of 500 for 18 h. Uninfected cells (UI), human beta MHC (MOI 500, 18 h), and human aMHC (MOI 500, 18 h) were used as controls. Cells were loaded with fura-2 (1 mu M, 15 min) after 48 h. Sarcomere shortening and calcium transients were recorded in CO2 buffered M199 media (36 degrees +/- 1 C) with and without 10 nM isoproterenol (Iso). The A1004S mutation resulted in decreased peak sarcomere shortening while P830L demonstrated near normal shortening kinetics at baseline. In the presence of Iso, the A1004S sarcomere shortening was identical to the beta MHC shortening while the P830L was identical to the alpha MHC control. All experimental groups had identical calcium transients. Despite a shared association with DCM, the P830L and A1004S alpha MHC mutations alter myocyte contractility in completely different ways while at the same preserving peak intracellular calcium.

• 出版日期2017-2-1