Qingchun Liang1, Yanting Chen2, Chuanxiang Li1, Lihe Lu2. 1. Department of Anesthesiology, Third Affiliated Hospital, Southern Medical University, Guangzhou 510630, China. 2. Department of Pathophysiology, Zhongshan Medical School, Sun Yat-Sen University, Guangzhou 510080, China.
Abstract
OBJECTIVE: To determine whether quercetin inhibits oxidized low-density lipoprotein (Ox-LDL)-induced osteogenic differentiation and calcification of vascular smooth muscle cells (VSMCs) and understand the underlying mechanism. METHODS: The calcification of human VSMCs following Ox-LDL treatment was assessed using alizarin red staining and by detecting ALP activity. The mRNA expressions of the bone-related genes including Msx2, BMP2 and Osterix, and the contractile proteins including SMA and SM22a were analyzed using qPCR. The effects of quercetin were investigated on OxLDL-induced VSMC calcification and changes in ALP activity, expressions of Msx2, BMP2, Osterix, SMA and SM22a, ROS levels and SOD activity. The effect of Toll like receptor 4 (TLR4) silencing mediated by siRNA transfection on cell calcification, ALP activity, gene expressions and ROS levels were investigated. RESULTS: Ox-LDL treatment promoted VSMC calcification and up-regulated TLR4 expression. Quercetin treatment significantly attenuated Ox-LDL-induced VSMC calcification, reduced ALP activity, down-regulated the expression levels of Msx2, BMP2 and Osterix, and up-regulated the expressions of vascular smooth muscle contractile proteins SMA and SM22a. In addition, Quercetin treatment markedly increased SOD activity, reduced ROS levels and TLR4 expression in VSMCs. Silencing TLR4 expression using TLR4 siRNA also significantly decreased calcification of the VSMCs. CONCLUSIONS: Quercetin inhibits Ox-LDL-induced VSMC calcification in VSMCs possibly by targeting the ROS/TLR4 signaling pathway.
OBJECTIVE: To determine whether quercetin inhibits oxidized low-density lipoprotein (Ox-LDL)-induced osteogenic differentiation and calcification of vascular smooth muscle cells (VSMCs) and understand the underlying mechanism. METHODS: The calcification of human VSMCs following Ox-LDL treatment was assessed using alizarin red staining and by detecting ALP activity. The mRNA expressions of the bone-related genes including Msx2, BMP2 and Osterix, and the contractile proteins including SMA and SM22a were analyzed using qPCR. The effects of quercetin were investigated on OxLDL-induced VSMC calcification and changes in ALP activity, expressions of Msx2, BMP2, Osterix, SMA and SM22a, ROS levels and SOD activity. The effect of Toll like receptor 4 (TLR4) silencing mediated by siRNA transfection on cell calcification, ALP activity, gene expressions and ROS levels were investigated. RESULTS: Ox-LDL treatment promoted VSMC calcification and up-regulated TLR4 expression. Quercetin treatment significantly attenuated Ox-LDL-induced VSMC calcification, reduced ALP activity, down-regulated the expression levels of Msx2, BMP2 and Osterix, and up-regulated the expressions of vascular smooth muscle contractile proteins SMA and SM22a. In addition, Quercetin treatment markedly increased SOD activity, reduced ROS levels and TLR4 expression in VSMCs. Silencing TLR4 expression using TLR4 siRNA also significantly decreased calcification of the VSMCs. CONCLUSIONS:Quercetin inhibits Ox-LDL-induced VSMC calcification in VSMCs possibly by targeting the ROS/TLR4 signaling pathway.
Authors: F Parhami; A D Morrow; J Balucan; N Leitinger; A D Watson; Y Tintut; J A Berliner; L L Demer Journal: Arterioscler Thromb Vasc Biol Date: 1997-04 Impact factor: 8.311
Authors: Chang Hyun Byon; Amjad Javed; Qun Dai; John C Kappes; Thomas L Clemens; Victor M Darley-Usmar; Jay M McDonald; Yabing Chen Journal: J Biol Chem Date: 2008-03-31 Impact factor: 5.157