Abstract 15753: Evidence that microRNA-21 plays a role in Atrial Natriuretic Peptide- and Nitric Oxide-dependent Human Vascular Smooth Muscle Cellcontraction/relaxation
Micro-RNAs (miRs) are endogenous small RNA molecules that suppress gene expression by binding to complementary sequences in the 3’ untranslated regions (UTRs) of their target genes. MiRs have been implicated in many diseases, including cardiovascular disorders and the role that these plays in cell signaling are just being realized. The present study examines the role of miR-21 in vasodilatory signaling by atrial natriuretic peptide (ANP) and nitric oxide (NO). Since the receptors for ANP and NO are ligand-activated guanylyl cyclases this study specifically focuses on cGMP and cGMP-dependent kinase (CGK). MicroRNA microarray anaylsis was carried out on human vascular smooth muscle cells (HVSMC) treated with ANP (10nM, 4hrs) and S-nitroso-N-acetylpenicillamine (SNAP) (100uM, 4hrs), a NO donor. Out of more than 50 miRs that showed significant changes in their expression, we chose miR-21 as it is widely implicated in cardiovascular disorders. Both ANP and SNAP down-regulated miR-21 in miR microarray analysis which was further confirmed by quantitative real time PCR (qRT-PCR). cGMP analogue, 8-bromo cGMP mimicked and KT-5823, a cGK inhibitor, blocked the regulation of miR-21 by ANP- and SNAP. Collagen gel lattice contraction assays using HVSMC transfected with pre-mir-21 showed contraction and with anti-miR-21 showed relaxation of HVSMC. ANP and SNAP abrogated pre-miR-21-induced HVSMC contraction. We identified by computational algorithms and confirmed by Western blot analysis new intracellular targets of miR-21, i.e., cofilin-2 (CFL-2) and Myosin phosphatase and Rho interacting protein (M-RIP). Further miR-21 levels are elevated in endothelial nitric oxide synthase and caveolin1 knockout (eNOS/cav1 -/-) mice. The present results implicate miR-21 in cGMP signaling and vascular smooth muscle cell contraction and raise a possibility that miR-21 and anti-mir-21 might be a diagnostic biomarker and a potential therapeutic agent, respectively for hypertension.
- Atrial natriuretic peptide (factor)
- Nitric oxide
- Vasodilator agents
- Smooth muscle regulation
- Receptor-mediated signaling
- © 2011 by American Heart Association, Inc.