title: Wnt16 attenuates TGFβ-induced chondrogenic transformation in vascular smooth muscle.
abstract: OBJECTIVE
  Phenotypic plasticity of vascular smooth muscle cells (VSMCs) contributes to cardiovascular disease. Chondrocyte-like transformation of VSMCs associates with vascular calcification and underlies the formation of aortic cartilaginous metaplasia induced in mice by genetic loss of matrix Gla protein (MGP). Previous microarray analysis identified a dramatic downregulation of Wnt16 in calcified MGP-null aortae, suggesting an antagonistic role for Wnt16 in the chondrogenic transformation of VSMCs.
  
  
  RESULTS
  Wnt16 is significantly downregulated in MGP-null aortae, before the histological appearance of cartilaginous metaplasia, and in primary MGP-null VSMCs. In contrast, intrinsic TGFβ is activated in MGP-null VSMCs and is necessary for spontaneous chondrogenesis of these cells in high-density micromass cultures. TGFβ3-induced chondrogenic transformation in wild-type VSMCs associates with Smad2/3-dependent Wnt16 downregulation, but Wnt16 does not suppress TGFβ3-induced Smad activation. In addition, TGFβ3 inhibits Notch signaling in wild-type VSMCs, and this pathway is downregulated in MGP-null aortae. Exogenous Wnt16 stimulates Notch activity and attenuates TGFβ3-induced downregulation of Notch in wild-type VSMCs, prevents chondrogenesis in MGP-null and TGFβ3-treated wild-type VSMCs, and stabilizes expression of contractile markers of differentiated VSMCs.
  
  
  CONCLUSIONS
  We describe a novel TGFβ-Wnt16-Notch signaling conduit in the chondrocyte-like transformation of VSMCs and identify endogenous TGFβ activity in MGP-null VSMCs as a critical mediator of chondrogenesis. Our proposed model suggests that the activated TGFβ pathway inhibits expression of Wnt16, which is a positive regulator of Notch signaling and a stabilizer of VSMC phenotype. These data advance the comprehensive mechanistic understanding of VSMC transformation and may identify a novel potential therapeutic target in vascular calcification.
authors.affiliation: From the Department of Biochemistry and Molecular Biology, School of Medicine, University of Maryland, Baltimore.
authors.forename: Kelly E
authors.initials: KE
authors.lastname: Beazley
authors.affiliation: From the Department of Biochemistry and Molecular Biology, School of Medicine, University of Maryland, Baltimore.
authors.forename: Dmitry
authors.initials: D
authors.lastname: Nurminsky
authors.affiliation: From the Department of Biochemistry and Molecular Biology, School of Medicine, University of Maryland, Baltimore.
authors.forename: Florence
authors.initials: F
authors.lastname: Lima
authors.affiliation: From the Department of Biochemistry and Molecular Biology, School of Medicine, University of Maryland, Baltimore.
authors.forename: Chintan
authors.initials: C
authors.lastname: Gandhi
authors.affiliation: From the Department of Biochemistry and Molecular Biology, School of Medicine, University of Maryland, Baltimore. mnurminskaya@som.umaryland.edu.
authors.forename: Maria V
authors.initials: MV
authors.lastname: Nurminskaya
mesh_terms: D000818:Animals; D001011:Aorta / Q000378:metabolism; D019556:COS Cells; D002135:Calcium-Binding Proteins / Q000172:deficiency / Q000235:genetics; D054338:Cell Transdifferentiation; D002522:Chlorocebus aethiops; D019902:Chondrocytes / Q000378:metabolism* / Q000473:pathology; D020219:Chondrogenesis; D016326:Extracellular Matrix Proteins / Q000172:deficiency / Q000235:genetics; D008679:Metaplasia; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D009131:Muscle, Smooth, Vascular / Q000378:metabolism* / Q000473:pathology; D032389:Myocytes, Smooth Muscle / Q000378:metabolism* / Q000473:pathology; D010641:Phenotype; D034622:RNA Interference; D051381:Rats; D051880:Receptors, Notch / Q000378:metabolism; D015398:Signal Transduction; D014162:Transfection; D016212:Transforming Growth Factor beta / Q000378:metabolism*; D053773:Transforming Growth Factor beta1 / Q000378:metabolism; D053782:Transforming Growth Factor beta3 / Q000378:metabolism; D061205:Vascular Calcification / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D051153:Wnt Proteins / Q000235:genetics / Q000378:metabolism*; D000097568:Matrix Gla Protein
chemical_list: D002135:Calcium-Binding Proteins; D016326:Extracellular Matrix Proteins; D051880:Receptors, Notch; D016212:Transforming Growth Factor beta; D053773:Transforming Growth Factor beta1; D053782:Transforming Growth Factor beta3; D051153:Wnt Proteins; D000097568:Matrix Gla Protein; C508961:Tgfb1 protein, mouse; C509045:Tgfb3 protein, mouse; C417262:WNT16 protein, human; C585687:Wnt16 protein, mouse
keywords: Notch protein; TGF-beta; Wnt16 protein, mouse; chondrogenesis; muscle, smooth, vascular; vascular calcification