High glucose-induced apoptosis in cultured podocytes involves TRPC6-dependent calcium entry via the RhoA/ROCK pathway

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• 作者：He Yang ; Bo Zhao ; Chang Liao ; Rui Zhang ; Kexin Meng ; Jia Xu ; Jundong Jiao ; ^{jiaojundong@yahoo.com.cn}
• 关键词：TRPC6 ; Podocytes ; ROS ; RhoA GTPase ; Apoptosis
• 刊名：Biochemical and Biophysical Research Communications
• 出版年：2013
• 出版时间：3 May, 2013
• 年：2013
• 卷：434
• 期：2
• 页码：394-400
• 全文大小：1847 K

文摘

Increasing evidence indicates that podocyte apoptosis is a key event in the development of diabetic nephrology. However, the underlying mechanism of this apoptosis remains poorly understood. In this study, we report that high levels of glucose enhanced the expression of TRPC6 and TRPC6-dependent Ca²⁺ influx, but glucose levels did not affect TRPC1 and TRPC5 expression. TRPC6 knockdown by siRNA interference attenuated the observed increase in glucose-induced podocyte apoptosis. High glucose levels also increased the generation of ROS; inhibition of ROS activity by N-acetyl-l-cysteine attenuated the high glucose-induced increase in TRPC6 expression and Ca²⁺ influx. Exogenous treatment with H₂O₂ mimicked the high glucose response, resulting in an increase in TRPC6 expression and Ca²⁺ influx. Taken together, these data suggest that high glucose levels induce ROS, thereby mediating TRPC6 expression and Ca²⁺ influx. Because RhoA activity is increased following TRPC6 activation, we investigated whether TRPC6 is involved in high glucose-induced apoptosis via the RhoA/ROCK pathway. We report that high glucose levels produced an increase in RhoA activity, and this effect was abolished by the knockdown of TRPC6. Moreover, inhibition of the RhoA/ROCK pathway by a ROCK inhibitor, Y27632, also attenuated high glucose-induced apoptosis. We conclude that TRPC6 is involved in high glucose-induced podocyte apoptosis through the RhoA/ROCK pathway.