TGF-β1下调炎性巨噬细胞RAW264.7 TLR4受体的表达

TGF-β1 down-regulate TLR4 expression in the macrophage RAW264.7

目的探讨TGF-β1对小鼠巨噬细胞RAW264.7 TLR4受体表达的调节作用。方法 Teal-Time PCR法检测RAW264.7细胞TGF-β1和TLR4受体mRNA表达,ELISA法检测RAW264.7细胞TGF-β1的分泌,流式细胞术检测RAW264.7细胞TLR4受体的表达。结果一定剂量的LPS促进RAW264.7分泌TGF-β1,且呈剂量依赖关系,一定剂量的TGF-β1单独刺激下调RAW264.7的TLR4受体的表达,TGF-β1能够下调LPS活化的RAW264.7细胞TLR4受体表达。结论 TGF-β1可以通过下调巨噬细胞TLR4受体表达来控制机体炎性反应,这可能是TGF-β1作为免疫抑制剂抑制炎症反应的重要途径之一。

TGF-β1 is a multifunctional growth regulator,which has a variety of biological effects on the immune cells.Previous reports have shown that TGF-β1 plays a negative role in toll-like receptor mediated immune responses;however,the precise mechanism is still unknown.In the present study,we aimed to investigate the regulation of TGF-β1 on the expression of TLR4 on the surface of macrophages.The expression of TGF-β1 and TLR4 mRNA were detected by Real-time PCR,the secretion of TGF-β1 in RAW264.7 was measured by ELISA,and expression of TLR4 on the surface of RAW264.7 was evaluated by FACS.Our results showed that LPS treatment promoted RAW264.7 to secrete TGF-β1 in a dose dependent manner,and TGF-β1 could inhibit the gene and protein expression of macrophage TLR4 in a dose dependent way;furthermore,TGF-β1 down-regulated the TLR4 gene and protein expression in RAW264.7 stimulated with LPS.Thus,TGF-β1 could regulate inflammation by down-regulation of the expression of TLR4 in macrophages,which may be one of the major ways that TGF-β1 control inflammation.