GPR120 Regulating The Function Of The Macrophage

Objective: We carried this study to explore the role of GPR120 in cytokine secretion and phagocytosis of macrophage from the different tissue and its mechanism.Methods: This study measured the expression level of GPR120 and some cytokines in mouse peritoneal macrophages and alveolar macrophages using real time RT-PCR method.The correlation between GPR120 expression level and the expression level of cytokines was analyzed.Phagocytosis of macrophage in the absence and presence of GPR120 agonist TUG-891 was assessed by flow cytometry.Meanwhile we observed the change of intracellular calcium with confocal microscope.Results: The results showed that GPR120 expression level was significantly higher in alveolar macrophages than peritoneal macrophages.The expression levels of interleukin-1(IL-1)and tumor necrosis factor-alpha(TNF-?)were also significantly higher in alveolar macrophages than peritoneal macrophages.In contrast,the expression levels of interleukin-10(IL-10)and interleukin-6(IL-6)were significantly lower in alveolar macrophages than peritoneal macrophages.In peritoneal macrophages,GPR120 expression level was positively correlated to IL-10(R=0.928),IL-6(R=0.95)and TNF-?(R=0.93),but it was negatively correlated to IL-1(R=0.914).In alveolar macrophages,GPR120 expression level was positively correlated to IL-1(R=0.911),IL-6(R=0.76)and TNF-?(R=0.836),but it was negatively correlated to IL-10(R=0.955).The results indicate that GPR120 expression in macrophages show heterogeneity and are correlated to cytokine expression.Compared to control,TUG-891 treated alveolar macrophage shows that the phagocytosis is inhibited.(P?0.01)Meanwhile,GPR120 activation by TUG-891 induces transiently intracellular calcium increasing(P?0.05).The results suggest that increased intracellular calcium by GPR120 activation may be involved in the inhibition of phagocytosis of macrophage.Conclusion:The expression of GPR120 is different in macrophage of different tissue,and there is a certain correlation between expression of GPR120 and cytokine.Activation of GPR120 increases intracellular calcium which may be involved in intracellular signal pathway inhibiting phagocytosis of alveolar macrophage.