title: An epigenetic regulatory loop controls pro-osteogenic activation by TGF-β1 or bone morphogenetic protein 2 in human aortic valve interstitial cells.
abstract: Calcific aortic valve disease (CAVD) is common in the elderly population, but pharmacological interventions for managing valvular calcification are unavailable. Transforming growth factor β1 (TGF-β1) and bone morphogenetic protein 2 (BMP-2) induce pro-osteogenic activation of human aortic valve interstitial cells (AVICs) that play an important role in valvular calcification. However, the molecular mechanism underlying pro-osteogenic activation in AVICs is incompletely understood. Here, we investigated an epigenetic regulatory mechanism in human AVIC pro-osteogenic activation induced by TGF-β1 and BMP-2. Microarray and real-time PCR analyses revealed that microRNA (miR)-486 up-regulation and miR-204 down-regulation were characteristic changes in TGF-β1- and BMP-2-stimulated normal AVICs and in AVICs from calcified valves. Both TGF-β1 and BMP-2 down-regulated miR-204 through Smad pathways. Interestingly, an miR-486 antagomir diminished the effect of TGF-β1 and BMP-2 on miR-204 levels and calcium deposit formation. Furthermore, the miR-486 antagomir increased the expression of Smurf2, a Smad inhibitor, in the presence or absence of TGF-β1 or BMP-2 stimulation, whereas a miR-486 mimic reduced Smurf2 expression. Smurf2 knockdown augmented TGF-β1- or BMP-2-induced miR-204 down-regulation and resulted in increased expression of the osteoblastic biomarkers Osx and Runx2. In summary, we found that TGF-β1 and BMP-2 up-regulate miR-486 and down-regulate miR-204 in human AVICs to promote pro-osteogenic activity and that miR-486 inhibits Smurf2 expression to augment the miR-204 down-regulation. We conclude that the miR-486-Smurf2-Smad loop plays an important role in regulating AVIC pro-osteogenic activation in response to TGF-β1 or BMP-2. Targeting this regulatory loop may have therapeutic potential for suppressing aortic valve calcification.
authors.affiliation: From the Department of Surgery, University of Colorado Denver, Aurora, Colorado 80045 and.
authors.forename: Rui
authors.initials: R
authors.lastname: Song
authors.affiliation: From the Department of Surgery, University of Colorado Denver, Aurora, Colorado 80045 and.
authors.forename: David A
authors.initials: DA
authors.lastname: Fullerton
authors.affiliation: From the Department of Surgery, University of Colorado Denver, Aurora, Colorado 80045 and.
authors.forename: Lihua
authors.initials: L
authors.lastname: Ao
authors.affiliation: the Department of Pathophysiology, Guangdong Key Laboratory of Shock and Microcirculation Research, Southern Medical University, Guangzhou 510515, China.
authors.forename: Ke-Seng
authors.initials: KS
authors.lastname: Zhao
authors.affiliation: From the Department of Surgery, University of Colorado Denver, Aurora, Colorado 80045 and Xianzhong.meng@ucdenver.edu.
authors.forename: Xianzhong
authors.initials: X
authors.lastname: Meng
mesh_terms: D000368:Aged; D001021:Aortic Valve / Q000378:metabolism* / Q000473:pathology; D055396:Bone Morphogenetic Protein 2 / Q000378:metabolism*; D002478:Cells, Cultured; D015536:Down-Regulation; D044127:Epigenesis, Genetic; D005260:Female; D006349:Heart Valve Diseases / Q000378:metabolism* / Q000473:pathology; D006801:Humans; D008297:Male; D035683:MicroRNAs / Q000096:biosynthesis; D008875:Middle Aged; D010006:Osteoblasts / Q000378:metabolism / Q000473:pathology; D010012:Osteogenesis; D015398:Signal Transduction; D053773:Transforming Growth Factor beta1 / Q000378:metabolism*; D044767:Ubiquitin-Protein Ligases / Q000378:metabolism; D015854:Up-Regulation; D061205:Vascular Calcification / Q000378:metabolism* / Q000473:pathology
chemical_list: C525718:BMP2 protein, human; D055396:Bone Morphogenetic Protein 2; C549404:MIRN204 microRNA, human; D035683:MicroRNAs; C508960:TGFB1 protein, human; D053773:Transforming Growth Factor beta1; C471641:SMURF2 protein, human; D044767:Ubiquitin-Protein Ligases
keywords: aortic valve; calcification; gene regulation; growth factor; microRNA (miRNA); signaling