黄芪甲苷可抑制炎性诱导星形胶质细胞激活及炎症反应

Astragaloside inhibits astrocyte activation and inflammatory response induced by inflammation

背景:星形胶质细胞在中枢神经系统疾病的病理中起着重要作用。星形胶质细胞的表型变化及功能改变,提示其可能是中枢神经系统疾病的有效治疗靶点。前期研究证实,黄芪甲苷可以抑制脂多糖(lipopolysaccharide,LPS)诱导的星形胶质细胞炎性反应,其是否可以通过Notch-1及其下游信号通路调控星形胶质细胞表型和功能,尚不清楚。目的:探讨黄芪甲苷对炎性诱导的星形胶质细胞激活及炎症反应的影响及可能机制。方法:体外培养新生C57BL/6小鼠大脑皮质星形胶质细胞,CCK-8法检测星形胶质细胞活力确定黄芪甲苷及Notch活性抑制剂DAPT的最适浓度;然后将星形胶质细胞分为5组:PBS组、LPS组、LPS+黄芪甲苷组、LPS+DAPT组和LPS+DAPT+黄芪甲苷组,ELISA法检测炎性因子分泌水平,Griess法检测一氧化氮水平,用Transwell小室将星形胶质细胞与脾脏单个核细胞共培养,观察CD4 T细胞的迁移情况,免疫荧光染色检测星形胶质细胞活化标志物GFAP、星形胶质细胞的A1标记物C3、A2标记物S100A10以及信号通路相关Notch-1、Jag-1的表达,Western blot法检测CFB、C3、S100A10、PTX3、Notch-1、Jag-1和Hes的表达。结果与结论:①根据CCK-8结果,筛选黄芪甲苷终浓度为25μmol/L,DAPT终浓度为50μmol/L进行后续实验;②与PBS组相比,LPS组白细胞介素6、白细胞介素12和一氧化氮分泌水平显著升高(P<0.05,P<0.05,P<0.01);与LPS组相比,LPS+黄芪甲苷组、LPS+DAPT组、LPS+DAPT+黄芪甲苷组白细胞介素6(均为P<0.05)、白细胞介素12(P>0.05,P<0.05,P<0.05)和一氧化氮(P<0.05,P<0.01,P<0.01)分泌显著减少;③与PBS组相比,LPS组星形胶质细胞激活明显,GFAP表达明显增多,CD4 T细胞的迁移数量明显增多(P<0.01);与LPS组相比,LPS+黄芪甲苷组、LPS+DAPT组、LPS+DAPT+黄芪甲苷组星形胶质细胞激活受到显著抑制,CD4 T细胞迁移减少(P<0.05,P<0.05,P<0.01);④与PBS组相比,LPS组A1型标记物C3和CFB的表达增加(P<0.01,P<0.05),而A2型标记物S100A10和PTX3的表达减少(P<0.01,P<0.05);与LPS组相比,LPS+黄芪甲苷组、LPS+DAPT组、LPS+DAPT+黄芪甲苷组C3(均为P<0.01)和CFB(均为P<0.05)的表达显著减少,S100A10(均为P<0.01)和PTX3(P<0.05,P<0.05和P>0.05)的表达增加;⑤与PBS组相比,LPS组Jag-1、Notch-1和Hes表达明显增加(均为P<0.01);与LPS组相比,LPS+黄芪甲苷组、LPS+DAPT组、LPS+DAPT+黄芪甲苷组Jag-1(均为P<0.01)、Notch-1(均为P<0.01)和Hes(P<0.05,P<0.01,P<0.01)表达显著减少;⑥结果表明:黄芪甲苷可通过调控Notch-1信号通路促进星形胶质细胞由A1型向A2型转化,减少炎性因子的分泌和CD4 T细胞的迁移,从而抑制星形胶质细胞的激活和炎性反应。

BACKGROUND:Astrocytes play an important role in the pathology of central nervous system diseases.The phenotypic and functional changes in astrocytes suggest that it may be an effective therapeutic target for central nervous system diseases.Our previous studies have confirmed that astragaloside can inhibit the lipopolysaccharide-induced astrocyte inflammatory response.Whether astragaloside can regulate the phenotype and function of astrocytes through Notch-1 and its downstream signaling pathway remains unclear.OBJECTIVE:To explore the effect of astragaloside on astrocyte activation and inflammatory response induced by inflammation and its possible mechanism.METHODS:Cerebral cortex astrocytes derived from neonatal C57BL/6 mouse were cultured in vitro.CCK-8 assay was used to determine the optimum concentration of astragaloside and Notch active inhibitor DAPT.The astrocytes were divided into five groups:PBS group,lipopolysaccharide group,lipopolysaccharide+astragaloside group,lipopolysaccharide+DAPT group and lipopolysaccharide+DAPT+astragaloside group.The secretion level of inflammatory factors was detected by ELISA,and the level of nitric oxide was detected by Griess method.The astrocytes and splenic mononuclear cells were co-cultured in Transwell chamber to observe the migration of CD4T cells.The expression of astrocyte activation marker GFAP,A1 marker C3 and A2 marker S100A10 as well as Notch 1 and Jag-1 was detected by immunofluorescence staining.The expressions of CFB,C3,S100A10,PTX3,Notch-1,Jag-1,and Hes were detected by western blot assay.RESULTS AND CONCLUSION:(1)According to the results of CCK8 assay,the final concentration of astragaloside was selected as 25μmol/L and the final concentration of DAPT was 50μmol/L for follow-up experiments.(2)Compared with PBS group,interleukin-6,interleukin-12 and nitric oxide secretion levels in the lipopolysaccharide group were significantly increased(P<0.05,P<0.05,P<0.01).Compared with the lipopolysaccharide group,interleukin-6(all P<0.05),interleukin-12(P>0.05,P<0.05,P<0.05)and nitric oxide(P<0.05,P<0.01,P<0.01)secretion significantly reduced in the lipopolysaccharide+astragaloside group,lipopolysaccharide+DAPT group,lipopolysaccharide+DAPT+astragaloside group.(3)Compared with the PBS group,the expression of GFAP that is the marker of activated astrocytes and the migration of CD4 T cells were significantly increased in the lipopolysaccharide group(P<0.01).Compared with the lipopolysaccharide group,astrocyte activation was significantly inhibited and CD4 T cell migration was significantly reduced in the lipopolysaccharide+astragaloside,lipopolysaccharide+DAPT,lipopolysaccharide+DAPT+astragaloside group(P<0.05,P<0.05,P<0.01).(4)Compared with the PBS group,the expressions of A1 markers C3 and CFB in the lipopolysaccharide group were increased(P<0.01,P<0.05),and the expressions of A2 markers S100A10 and PTX3 were decreased(P<0.01,P<0.05).Compared with the lipopolysaccharide group,C3(all P<0.01)and CFB(both P<0.05)were significantly reduced and S100A10(all P<0.01)and PTX3(P<0.05,P<0.05 and P>0.05)were increased in the lipopolysaccharide+astragaloside,lipopolysaccharide+DAPT,lipopolysaccharide+DAPT+astragaloside group.(5)Compared with the PBS group,the expressions of Jag-1,Notch-1 and Hes in the lipopolysaccharide group were significantly increased(all P<0.01).Compared with the lipopolysaccharide group,the expressions of Jag-1(all P<0.01),Notch-1(all P<0.01)and Hes(P<0.05,P<0.01 and P<0.01)were significantly reduced in the lipopolysaccharide+astragaloside,lipopolysaccharide+DAPT,lipopolysaccharide+DAPT+astragaloside group.(6)The results indicate that astragaloside can promote the transformation of astrocytes from A1 to A2 by regulating Notch-1 signaling pathway,reduce the secretion of inflammatory factors and the migration of CD4 T cells,and thus inhibit astrocyte activation and inflammatory response.