miR-206 Mediates YAP-Induced Cardiac Hypertrophy and Survival.

Rationale: In Drosophila, the Hippo signaling pathway negatively regulates organ size by suppressing cell proliferation and survival through the inhibition of Yorkie, a transcriptional cofactor. Yes-associated protein (YAP), the mammalian homolog of Yorkie, promotes cardiomyocyte growth and survival in postnatal hearts. However, the underlying mechanism responsible for the beneficial effect of YAP in cardiomyocytes remains unclear.

Yes-associated protein isoform 1 (Yap1) promotes cardiomyocyte survival and growth to protect against myocardial ischemic injury.

Yap1 is an important regulator of cardiomyocyte proliferation and embryonic heart development, yet the function of endogenous Yap1 in the adult heart remains unknown. We studied the role of Yap1 in maintaining basal cardiac function and in modulating injury after chronic myocardial infarction (MI). Cardiomyocyte-specific homozygous inactivation of Yap1 in the postnatal heart (Yap(F/F)Cre) elicited increased myocyte apoptosis and fibrosis, dilated cardiomyopathy, and premature death.

Lats2 is a negative regulator of myocyte size in the heart.

Mammalian sterile 20-like kinase (Mst)1 plays an important role in mediating apoptosis and inhibiting hypertrophy in the heart. Because Hippo, a Drosophila homolog of Mst1, forms a signaling complex with Warts, a serine/threonine kinase, which in turn stimulates cell death and inhibits cell proliferation, mammalian homologs of Warts, termed Lats1 and Lats2, may mediate the function of Mst1. We here show that Lats2, but not Lats1, dose-dependently increased apoptosis in cultured cardiac myocytes.

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.

Downregulation of cyclin-dependent kinase inhibitor; p57(kip2), is involved in the cell cycle progression of vascular smooth muscle cells.

Immature vascular smooth muscle cells (VSMCs) proliferate responding to extrinsic mitogens and accumulate in neointima after arterial injuries. Cell proliferation is positively regulated by cyclin/cyclin-dependent kinase (CDK) complex and negatively controlled by CDK inhibitors; CKIs such as p27(kip1) and p57(kip2). In this study, embryonic rat thoracic aorta VSMCs; A10 were G0/G1 arrested by serum starvation, re-stimulated with serum, and harvested every four hours.

A novel mutation in FKBP12.6 binding region of the human cardiac ryanodine receptor gene (R2401H) in a Japanese patient with catecholaminergic polymorphic ventricular tachycardia.

Catecholaminergic polymorphic ventricular tachycardia (CPVT) is an autosomal dominant inherited disorder characterized by adrenergic induced polymorphic ventricular tachycardias and associated with sudden cardiac death. The human cardiac ryanodine receptor gene (RyR2) was linked to CPVT. A 20-year-old male was referred to our hospital because of recurrent syncope after physical and emotional stress.