西格列汀对AGEs作用下系膜细胞自噬的影响

目的:探讨西格列汀对晚期糖基化终末产物(advanced glycation end products,AGEs)作用下系膜细胞细胞外基质和自噬相关蛋白表达的影响。方法:培养大鼠肾小球系膜细胞,共分5组,分别为正常对照(control)组、AGE组和不同浓度(5、10和20μmol/L)西格列汀组。培养48 h后采用MTT法测定细胞活力,采用ELISA法检测细胞培养上清胶原蛋白Ⅳ(collagen IV,Col IV)含量的变化。采用Western blot检测自噬相关蛋白beclin-1、腺苷酸活化蛋白激酶(adenosine monophosphate-activated protein kinase,AMPK)、p-AMPK、p70S6K和p-p70S6K的蛋白水平。结果:与control组比较,AGEs可明显引起系膜细胞活力和Col IV表达增加,不同浓度的西格列汀均可明显抑制AGEs诱导的系膜细胞活力和Col IV表达的增加;与control组比较,AGEs可引起系膜细胞自噬相关蛋白beclin-1表达和AMPK磷酸化水平下降,p70S6K磷酸化水平增加;不同浓度的西格列汀均可促进系膜细胞自噬相关蛋白beclin-1表达及AMPK磷酸化,抑制p70S6K磷酸化,并呈一定的浓度依赖性。结论:西格列汀可能通过引起系膜细胞的自噬发挥肾脏保护作用。

Effect of sitagliptin on autopaghy in mesangial cells induced by AGEs

AIM: To investigate the effect of sitagliptin on the autopaghy and the expression of extracellular matrix in mesangial cells induced by advanced glycation end products (AGEs). METHODS: The cells were divided into 5 groups:control group, AGE group, and sitagliptin (5, 10 and 20 μmol/L) groups. After 48 h, the cell viability was measured by MTT assay, and the content of collagen (Col) Ⅳ in the supernatant of the cell culture was detected by ELISA. The protein levels of beclin-1, adenosine monophosphate-activated protein kinase (AMPK), p-AMPK, p70S6K and p-p70S6K were determined by Western blot. RESULTS: Compared with control group, the viability and the expression of Col IV induced by AGEs in the cultured mesangial cells were significantly increased (P<0.01). Sitagliptin decreased the viability and the expression of Col IV induced by AGEs in the mesangial cells in a dose-dependent manner. AGEs significantly inhibited the protein levels of beclin-1 and p-AMPK, but significantly increased the protein level of p-p70S6K. Compared with AGE group, sitagliptin significantly reversed the above results in a dose-dependent manner. CONCLUSION: Autophagy may mediate the protective effect of sitagliptin on mesangial cells induced by AGEs.