Endocardial TRPC-6 Channels Act as Atrial Mechanosensors and Load-Dependent Modulators of Endocardial/Myocardial Cross-Talk

JACC Basic Transl Sci. 2017 Oct 30;2(5):575-590. doi: 10.1016/j.jacbts.2017.05.006. eCollection 2017 Oct.

Abstract

Mechanoelectrical feedback may increase arrhythmia susceptibility, but the molecular mechanisms are incompletely understood. This study showed that mechanical stretch altered the localization, protein levels, and function of the cation-selective transient receptor potential channel (TRPC)-6 in atrial endocardial cells in humans, pigs, and mice. In endocardial/myocardial cross-talk studies, addition of media from porcine atrial endocardium (AE) cells altered the calcium (Ca2+) transient characteristics of human-induced pluripotent stem cell-derived cardiomyocytes. These changes did not occur with media from stretched AE cells. Our data suggested that endocardial TRPC-6-dependent paracrine signaling may modulate myocardial Ca2+ homeostasis under basal conditions and protect against stretch-induced atrial arrhythmias.

Keywords: AE, atrial endocardium; AF, atrial fibrillation; APB, aminoethoxydiphenyl borate; Ab, antibody; CM, cardiomyocyte; Ca2+, calcium; Dil-Ac-LDL, dil acetylated−low-density lipoprotein; ET, endothelin; HUVEC, human umbilical vein endothelial cell; OAG, 1-oleoyl-2-acetyl-sn-glycerol; TAC, thoracic aortic constriction; TRPC, transient receptor potential channel; Tet, tetanus toxin; [Ca2+]i, intracellular global Ca2+; atrial endocardium; endothelium; iPS, induced pluripotent stem; mechanical stretch; transient receptor potential channels.