Department of Internal Medicine, College of Medicine, Severance Biomedical Science Institute, Yonsei University, Seodaemoon-Gu, Seoul, Korea.
Apoptosis. 2012 Jan;17(1):1-13. doi: 10.1007/s10495-011-0661-6.
Previous studies have demonstrated the importance of monocyte chemoattractant protein-1 (MCP-1) in the pathogenesis of diabetic nephropathy in terms of inflammation, but the direct role of the MCP-1/CCR2 system on podocyte apoptosis under diabetic conditions has never been explored. In vitro, mouse podocytes were exposed to a medium containing 30 mM glucose (HG) with or without CCR2 siRNA or CCR2 inhibitor (RS102895). Podocytes were also treated with MCP-1 or TGF-β1 with or without anti-TGF-β1 antibody, CCR2 siRNA, or CCR2 inhibitor. In vivo, 20 db/m and 20 db/db mice were divided into two groups, and ten mice from each group were treated with RS102895. Western blot and Hoechst 33342 or TUNEL staining were performed to identify apoptosis. HG-induced apoptosis and TGF-β1 levels were significantly abrogated by CCR2 inhibition. In addition, treatment with MCP-1 directly induced apoptosis via CCR2. Moreover, TGF-β1- and MCP-1-induced apoptosis were significantly ameliorated by the inhibition of CCR2 and anti-TGF-β1 antibody, respectively. Glomerular expression of cleaved caspase-3 and apoptotic cells within glomeruli were also significantly increased in db/db mice compared to db/m mice, and these increases were significantly attenuated in db/db + RS102895 mice. These results suggest that interactions between the MCP-1/CCR2 system and TGF-β1 may contribute to podocyte apoptosis under diabetic conditions.
先前的研究表明，单核细胞趋化蛋白-1（MCP-1）在糖尿病肾病的发病机制中具有重要作用，尤其是在炎症方面，但 MCP-1/CCR2 系统在糖尿病条件下对足细胞凋亡的直接作用尚未被探索。在体外，将小鼠足细胞暴露于含有 30mM 葡萄糖（HG）的培养基中，同时使用或不使用 CCR2 siRNA 或 CCR2 抑制剂（RS102895）。还将 MCP-1 或 TGF-β1 与抗 TGF-β1 抗体、CCR2 siRNA 或 CCR2 抑制剂一起处理足细胞。在体内，将 20db/m 和 20db/db 小鼠分为两组，每组 10 只小鼠用 RS102895 处理。通过 Western blot 和 Hoechst 33342 或 TUNEL 染色来鉴定凋亡。CCR2 抑制显著减弱了 HG 诱导的凋亡和 TGF-β1 水平。此外，MCP-1 直接通过 CCR2 诱导凋亡。此外，CCR2 抑制和抗 TGF-β1 抗体分别显著改善了 TGF-β1 和 MCP-1 诱导的凋亡。与 db/m 小鼠相比，db/db 小鼠肾小球中 cleaved caspase-3 和肾小球内凋亡细胞的表达也显著增加，而 db/db+RS102895 小鼠中的这些增加则显著减弱。这些结果表明，MCP-1/CCR2 系统与 TGF-β1 之间的相互作用可能导致糖尿病条件下足细胞凋亡。
