• Bobby Yanagawa, Fina Lovren, Yi Pan, Vinay Garg, Adrian Quan, Gilbert Tang, Krishna K Singh, Praphulla C Shukla, Nikhil P Kalra, Mark D Peterson, and Subodh Verma.
• Division of Cardiac Surgery, St. Michael's Hospital, University of Toronto, Toronto, Ontario, Canada.
• J. Thorac. Cardiovasc. Surg.. 2012 Jul 1;144(1):256-62.

ObjectiveBone morphogenetic protein-2 (BMP-2) is a major regulator of aortic valve calcification. MicroRNAs (miRNAs) are essential post-transcriptional modulators of gene expression and miRNA-141 is a known repressor of BMP-2-mediated osteogenesis. We hypothesized that miRNA-141 is a key regulator of aortic valve calcification.MethodsPorcine valvular interstitial cells were isolated, transfected with miRNA-141 or control, and stimulated with transforming growth factor-β. The BMP-2, extracellular signal-regulated kinase 1/2, and runt-related transcription factor 2 levels were determined by immunoblotting and reverse transcriptase polymerase chain reaction. To determine the role of miRNA-141 in bicuspid aortic valve disease, human bicuspid (n = 19) and tricuspid (n = 17) aortic valve leaflets obtained intraoperatively were submitted for GenoExplorer human microRNA array, immunoblotting, and histologic and immunohistochemical analyses.ResultsStimulation of porcine aortic valvular interstitial cells with transforming growth factor-β induced morphologic alterations consistent with myofibroblastic transformation, BMP-2 signaling, and calcification. Transfection with miRNA-141 restored transforming growth factor-β-induced valvular interstitial cell activation, BMP-2 signaling, and alkaline phosphatase activity (3.55 ± 0.18 vs 4.01 ± 0.21, P < .05), suggesting upstream regulation by miRNA-141. miRNA microarray demonstrated differential expression of 35 of 1583 miRNA sequences in the bicuspid versus tricuspid aortic valve leaflets, with a 14.5-fold decrease in miRNA-141 in the bicuspid versus tricuspid leaflets (P < .05). This was associated with significantly increased BMP-2 protein expression in bicuspid aortic valve compared with the tricuspid aortic valve leaflets (P < .001).ConclusionsWe report a completely novel role of miRNA-141 as a regulator of BMP-2-dependent aortic valvular calcification and demonstrate marked attenuation of miRNA-141 expression in patients with bicuspid aortic valve-associated aortic stenosis. Therapeutic targeting of miRNA-141 could serve as a novel strategy to limit progressive calcification in aortic stenosis.Copyright © 2012 The American Association for Thoracic Surgery. Published by Mosby, Inc. All rights reserved.

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