[MCPIP1 mediates MCP-1-induced vascular smooth muscle cell proliferation]

The aim of the present study is to investigate whether monocyte chemotactic protein-1 (MCP-1)-induced vascular smooth muscle cell (VSMC) proliferation is mediated via monocyte chemotactic protein-1 induced protein-1 (MCPIP1). MCPIP1 expressions in cultured VSMC were detected by real-time PCR and Western blot following MCP-1 incubation. After MCPIP1 was silenced by siRNA, cell number was counted by hemocytometer, VSMC activity was analyzed by CCK-8 kit, percentage of DNA synthesis was detected by EdU kit, percentage of S phase cell numbers were measured by flow cytometry, and c-fos mRNA expression induced by MCP-1 or platelet-derived growth factor (PDGF) was detected by real-time PCR. The results showed MCP-1 increased MCPIP1 mRNA and up-regulated MCPIP1 protein expression in dose- and time-dependent manners. Cell counts, cellular activity, the percentage of DNA synthesis, and the percentage of S phase cell numbers were remarkably decreased in MCPIP1 siRNA group, compared with those in MCP-1 group. The enhancing effect of MCP-1 or PDGF on c-fos mRNA expression was inhibited by MCPIP1 siRNA. These results suggest that MCP-1-induced VSMC proliferation is mediated via MCPIP1, and the underlying mechanism may involve c-fos expression up-regulation.