激活素A对巨噬细胞系RAW264.7细胞吞饮活性及TLR4表达的双向调节作用

目的探讨激活素A(ActivinA)对巨噬细胞系RAW264.7细胞活性的调节作用及其可能的机制。方法取对数生长期的小鼠巨噬细胞系RAW264.7细胞,加入1μg/ml脂多糖(LPS),继续培养8h,采用ELISA法检测细胞分泌ActivinA水平;分别加入ActivinA、LPS和ActivinA+LPS,中性红染料法检测细胞吞饮活性;流式细胞术分析细胞表面分子MHCⅠ、MHCⅡ及Toll样受体4(TLR4)的表达水平。结果LPS呈时间依赖性刺激RAW264.7细胞分泌ActivinA;ActivinA可明显促进静息RAW264.7细胞的吞饮活性,而对MHCⅠ、MHCⅡ及TLR4的表达水平无明显影响;ActivinA和LPS共同作用,ActivinA明显抑制了LPS活化的RAW264.7细胞的吞饮活性,并下调TLR4的表达。结论ActivinA可能以自分泌/旁分泌形式参与巨噬细胞活性调节,其抑制LPS作用与TLR4表达有关。

Dual Regulatory Effect of Activin A on Pinocytic Activity of Macrophage Cell Line RAW264.7 and TLR4 Expression

Objective To investigate the regulatory effect of activin A on activity of murine macrophage RAW264.7 and its possible mechanism.Methods The RAW264.7 cells at logarithmic growth phase were added with 1μg / ml LPS and further cultured for 8 h, then determined for activin A level by ELISA.Meanwhile, the RAW264.7 cells at logarithmic growth phase were added with activin A, LPS and activin A + LPS respectively and determined for pinocytic activity by neutral red staining.The expression levels of MHCⅠ, MHCⅡ and Toll-like receptor 4(TLR4)on surface of RAW264.7 cells were determined by flow cytometry.Results LPS showed a time-dependent stimulating effect on the secretion of activin A by RAW264.7 cells.Activin A increased the pinocytic activity of stationary RAW264.7 cells significantly, while showed no significant effect on the expression levels of MHC Ⅰ, MHCⅡ and TLR4.When RAW264.7 cells were treated with activin A + LPS, activin A inhibited the pinocytic activity of LPS-activated RAW264.7 cells significantly and down regulated the TLR4 expression.Conclusion Activin A might participate in the regulation of activity of macrophages by autocrine or paracrine, and its inhibitory effect on LPS might be related to TLR4 expression.