坎地沙坦抑制脂多糖诱导的toll样受体4及下游炎症因子的表达增加——不依赖血管紧张素Ⅱ1型受体(英文)

Candesartan inhibits LPS-induced expression increase of toll-like receptor 4 and downstream inflammatory factors likely via angiotensin Ⅱ type 1 receptor independent pathway in human renal tubular epithelial cells

本文旨在离体培养人肾小管上皮细胞株(human renal tubular epithelial cells,HKCs)上研究血管紧张素Ⅱ 1型受体阻断剂(angiotensin Ⅱ type 1 receptor blocker,ARB)坎地沙坦抗炎效应的机制。用流式细胞仪、Western blot、RT-PCR和ELISA技术分别检测HKCs的toll样受体4(toll-like receptor 4,TLR4)蛋白水平、血管紧张素II 1型受体(angiotensin Ⅱ type 1 receptor,AT1R)和磷酸化核因子-κB(nuclear factor-kappa B,NF-κB)p65蛋白、巨噬细胞趋化蛋白-1(macrophage chemoattractant protein-1,MCP-1)和RANTES的mRNA水平,以及MCP-1和RANTES在培养液中的蛋白浓度。结果显示,在离体培养的HKCs中,脂多糖(lipopolysaccharide,LPS)上调TLR4蛋白表达水平,增强NF-κB活化和下游炎症因子(包括MCP-1和RANTES)释放;坎地沙坦逆转LPS引起的TLR4表达的上调、NF-κB活化及MCP-1和RANTES的释放,但用siRNA下调AT1R表达并不改变坎地沙坦的这些效应。以上结果提示,坎地沙坦通过一条新的不依赖于AT1R的途径发挥抗炎效应。

The present study was to determine whether candesartan, an angiotensin II type 1 receptor blocker （ARB）, exerts anti- inflammatory effects through inhibiting the toll-like receptor 4 （TLR4） pathway in human renal tubular epithelial cells （HKCs）. The experiments were carried on cultured HKCs. By means of flow cytometry, Western blot, RT-PCR and ELISA techniques, the TLR4 protein, angiotensin II type 1 receptor （AT1R） and phosphorylated nuclear factor-kappa B （NF-κB） p65 protein level, mRNA levels of macrophage chemoattractant protein-1 （MCP-1） and regulated upon expression normal T cell expressed and secreted （RANTES）, as well as MCP-1 and RANTES protein concentrations in conditioned media were measured. The results showed that lipopolysaccharide （LPS） upregulated the TLR4 protein level in cultured HKCs. Application of LPS increased NF-r,B activation and induced release of its downstream inflammatory factors including MCP-1 and RANTES. Candesartan reversed LPS-induced upregulation of TLR4 expression, inhibited NF-κB activation, and reduced MCP-1 and RANTES release. However, knockdown on AT1R by siRNA did not change those previous effects of candesartan. These results suggest that candesartan-induced anti-inflammatory effect may be through a novel pathway, independent of AT 1R.