TRPM8参与薄荷醇对炎症因子负调控作用的机制

Role of TRPM8 in negative regulation of inflammatory factors by menthol

目的薄荷醇通过瞬时受体电位TRPM8对炎症因子负调控作用的机制。方法首先在整体动物实验,检测薄荷醇对小鼠下丘脑中TRPM8,核转录因子NF-κB以及炎症因子TNF-α表达水平的调控。然后通过体外实验,在细胞水平检测薄荷醇对PC12细胞中TRPM8、NF-κB和TNF-α表达的调控作用。最后,使用TRPM8表达敲低的PC12细胞系,检测薄荷醇对TRPM8、NF-κB和TNF-α调控作用的变化。结果(1)尾静脉注射薄荷醇,可以激活小鼠脑中TRPM8的表达,抑制核转录因子NF-κB和炎症因子TNF-α的表达。(2)薄荷醇可以激活PC12细胞中TRPM8的表达,抑制NF-κB和炎症因子TNF-α的表达。(3)在TRPM8敲低的PC12细胞中,薄荷醇对TRPM8表达无显著调控作用,对TNF-α表达的抑制作用转为激活作用。结论薄荷醇对炎症因子TNF-α及其上游核转录因子NF-κB的负调控作用依赖于其对TRPM8的激活作用。

Objective To elucidate the molecular mechanism of the negative regulation of inflammatory factors by menthol through transient receptor potential melastatin 8(TRPM8).Methods In an in vivo experiment,we detected expression of the cold-sensitive receptor TRPM8,nuclear transcription factor NF-κB,and inflammatory factor TNF-αafter intravenous injection of(-)-menthol.In an in vitro experiment,we examined the effect of menthol on TRPM8,NF-κB,and TNF-αexpression in PC12 cells.Finally,we examined the negative relationship between TRPM8 and TNF-αin PC12 cells(TRPM8 knockdown).Results The three main findings of this study are as follows.First,after intravenous injection of menthol,expression of the cold-sensitive receptor TRPM8 in the hypothalamus of mice was activated,and expression of the nuclear transcription factor NF-κB and inflammatory factor TNF-αwas inhibited.Second,in the neuron-like PC12 cells,menthol activated TRPM8 expression and inhibited NF-κB and TNF-α.Third,in PC12 cells with TRPM8 knockdown,menthol showed no significant effect on TRPM8 expression;in contrast,TNF-αexpression was activated.Conclusions The negative regulation of inflammatory factors by menthol depends on the activation of TRPM8 expression.