Interaction of BMP10 with Tcap may modulate the course of hypertensive cardiac hypertrophy

Elevated wall stress by hypertension induces an adaptive myocardial hypertrophy via releasing prohypertrophic hormones such as angiotensin II. In this study, we investigated the involvement of bone morphogenetic protein-10 (BMP10) in hypertension-induced cardiac hypertrophy. Expression of BMP10 was increased in the hypertrophied ventricles from hypertensive rats. BMP10 localized on cell surface and at stretch-sensing Z disc of cardiomyocytes, where BMP10 interacted with a protein called titin-cap (Tcap). A rare variant of the human BMP10 gene, Thr326Ile, was found to be associated with hypertensive dilated cardiomyopathy. The variant BMP10 demonstrated decreased binding to Tcap and increased extracellular secretion. Conditioned medium from cells transfected with wild-type or variant BMP10 induced hypertrophy in rat neonatal cardiomyocytes, except that medium from variant BMP10-carrying cells showed an enhanced effect reflecting the increased secretion. These observations suggested that hypertension induced expression of prohypertrophic BMP10, and the hypertrophic effect of BMP10 was modulated, at least in part, by its binding to Tcap at the Z disc.