Wnt16 attenuates TGF?-induced chondrogenic transformation in vascular smooth muscle.

ABSTRACT: 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.Wnt16 is significantly downregulated in MGP-null aortae, before the histological appearance of cartilaginous metaplasia, and in primary MGP-null VSMCs. In contrast, intrinsic TGF? is activated in MGP-null VSMCs and is necessary for spontaneous chondrogenesis of these cells in high-density micromass cultures. TGF?3-induced chondrogenic transformation in wild-type VSMCs associates with Smad2/3-dependent Wnt16 downregulation, but Wnt16 does not suppress TGF?3-induced Smad activation. In addition, TGF?3 inhibits Notch signaling in wild-type VSMCs, and this pathway is downregulated in MGP-null aortae. Exogenous Wnt16 stimulates Notch activity and attenuates TGF?3-induced downregulation of Notch in wild-type VSMCs, prevents chondrogenesis in MGP-null and TGF?3-treated wild-type VSMCs, and stabilizes expression of contractile markers of differentiated VSMCs.We describe a novel TGF?-Wnt16-Notch signaling conduit in the chondrocyte-like transformation of VSMCs and identify endogenous TGF? activity in MGP-null VSMCs as a critical mediator of chondrogenesis. Our proposed model suggests that the activated TGF? 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.

SUBMITTER: Beazley KE 

PROVIDER: S-EPMC4344425 | biostudies-literature | 2015 Mar

REPOSITORIES: biostudies-literature