Abstract 22: Histone Deacetylase (HDAC) 4 Controls Neointimal Hyperplasia via Stimulating Proliferation and Migration of Vascular Smooth Muscle Cells
Histone deacetylases (HDACs) are transcriptional co-regulators. We have recently demonstrated that a class IIa HDAC, HDAC4 promotes reactive oxygen species (ROS)-dependent vascular smooth muscle inflammation and mediates the development of hypertension in spontaneously hypertensive rats. Pathogenesis of hypertension is in part modulated by vascular structural remodeling via proliferation and migration of vascular smooth muscle cells (SMCs). We thus examined whether HDAC4 controls SMCs proliferation and migration. In rat mesenteric arterial SMCs, small interfering RNA (siRNA) against HDAC4 inhibited platelet-derived growth factor (PDGF)-BB-induced SMCs proliferation as determined by a cell counting (51% inhibition, n=7) or bromodeoxyuridine incorporation assay (95% inhibition, n=6) and migration as determined by Boyden chamber assay (71% inhibition, n=3). Expression and activity of HDAC4 were increased by PDGF-BB (30% increase, n=5 and 170% increase, n=4, respectively). HDAC4 siRNA inhibited phosphorylation of p38 (69% inhibition, n=5) and heat shock protein (HSP) 27 (91% inhibition, n=5) and expression of cyclin D1 (58% inhibition, n=5) as measured by Western blotting. HDAC4 siRNA also inhibited PDGF-BB-induce ROS production as measured fluorometrically using 2’ 7’-dichlorofluorescein diacetate (77% inhibition, n=4) and nicotinamide adenine dinucleotide phosphate oxidase activity as measured by lucigenin assay (61% inhibition, n=4). A Ca2+/calmodulin (CaM)-dependent protein kinase (CaMK) II inhibitor, KN93 inhibited PDGF-BB-induced SMCs proliferation (58% inhibition, n=4) and migration (75% inhibition, n=3) as well as phosphorylation of HDAC4 (84% inhibition, n=4). In vivo, a class IIa HDACs inhibitor, MC1568 prevented neointimal hyperplasia in mice carotid ligation model (54% inhibition, n=6). MC1568 also inhibited increased activity of HDAC4 in the neointimal lesions. The present results for the first time demonstrate that HDAC4 controls PDGF-BB-induced SMCs proliferation and migration through activation of p38/HSP27 signals via ROS generation in a CaMKII-dependent manner, which may lead to the neointima hyperplasia in vivo.
- © 2013 by American Heart Association, Inc.