G蛋白耦联胆汁酸受体激动剂INT777通过激活AMPK信号通路抑制施万细胞成髓鞘过程

G-protein-coupled bile acid receptor agonists INT777 inhibits myelination of Schwann cells by activating AMPK signaling pathway

目的:研究G蛋白耦联胆汁酸受体(G-protein-coupled bile acid receptor 1,GPBAR1,同时也被称为TGR5)特异性激动剂6α-乙基-23(S)-甲基胆酸[6 alpha-ethyl-23(S)-methylcholic acid,INT777]对原代施万细胞髓鞘形成的影响并初步探讨其可能的作用机制。方法:用5μmol/L的INT777处理二丁酰环腺苷酸(dibutyryl cyclic adenoslne phosphate,dbcAMP)诱导分化原代施万细胞成髓鞘模型,用免疫印迹(Western Blot)方法检测髓磷脂蛋白表达量的变化。同时,提取施万细胞总核糖核酸后用定量聚合酶链式反应试验检测INT777对髓鞘形成过程相关分子基因表达的影响。另外,用Western Blot方法检测INT777对单磷酸腺苷活化蛋白激酶/核糖体蛋白S6激酶(adenosine 5′-monophosphate-activated protein kinase/ribosomal S6 kinase,AMPK/S6K)信号途径的影响。结果:在dbcAMP诱导分化原代施万细胞成髓鞘过程中,5μmol/L INT777的处理抑制了髓鞘早期生长因子20,八聚体结合转录因子6,髓磷脂蛋白的表达,且5μmol/L INT777处理激活了AMPK的活性,抑制了雷帕霉素作用靶点信号通路。结论:INT777抑制dbcAMP诱导的施万细胞成髓鞘过程,这种抑制作用可能是通过激活施万细胞AMPK活性、抑制S6K活性实现的。

Objective:To investigate the effects of G-protein-coupled bile acid receptor 1(GPBAR1,also known as TGR5)specific agonist 6 alpha-ethyl-23(S)-methylcholic acid(INT777)on myelination in primary Schwann cells and the underlying mechanisms.Methods:Primary Schwann cells were treated with 5μmol/L INT777 and dibutiryl cyclic adenoslne phosphate(dbcAMP),and the changes of myelin protein zero were detected by Western Blot.Meanwhile,the total RNA was extracted from Schwann cells and quantitative real time polymerase chain reaction was employed for detecting myelin gene expression.In addition,the effect of INT777 on the adenosine 5′-monophosphate-activated protein kinase/ribosomal protein S6 kinase(AMPK/S6 K)signaling pathway was examined by Western Blot.Results:Treatment with 5μmol/L INT777 inhibited the expression of myelin early growth response-2,octamer-binding transcription factor 6,and myelin protein zero during dbcAMP-induced myelination of differentiated Schwann cells,and treatment with 5μmol/L INT777 activated AMPK activity and inhibited mTOR signaling pathway.Conclusion:INT777 attenuates dbcAMP-induced myelination of Schwann cells,which may be achieved by activating AMPK and inhibiting S6 K activity.