Yingjun Zang1, Shuang Liu1, Aili Cao2, Xiangyu Shan1, Wenjuan Deng1, Zhijun Li1, Hao Wang1, Yunman Wang1, Li Wang3, Wen Peng4,5. 1. Department of Nephrology, Putuo Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai, 200062, People's Republic of China. 2. Laboratory of Renal Disease, Putuo Hospital, Shanghai University of Traditional Chinese Medicine, 164 LanXi Road, Shanghai, 200062, People's Republic of China. 3. Laboratory of Renal Disease, Putuo Hospital, Shanghai University of Traditional Chinese Medicine, 164 LanXi Road, Shanghai, 200062, People's Republic of China. wanglitcm2007@163.com. 4. Department of Nephrology, Putuo Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai, 200062, People's Republic of China. pengwen_01@vip.sina.com. 5. Laboratory of Renal Disease, Putuo Hospital, Shanghai University of Traditional Chinese Medicine, 164 LanXi Road, Shanghai, 200062, People's Republic of China. pengwen_01@vip.sina.com.
Abstract
Loss of podocytes is a hallmark of diabetic nephropathy, and a growing body of evidence indicates that podocytes are susceptible to palmitic acid (PA). We have previously shown that AS-IV inhibited PA-induced podocyte apoptosis by activating sarcoendoplasmic reticulum Ca2+ ATPase (SERCA), which indicate calcium regulation may involve in the process. Immunofluorescence staining, Western blot and flow cytometry were used to measure the protective efficacy of AS-IV to ameliorate PA-induced ER stress and podocyte apoptosis. Meanwhile, AS-IV inhibited cytochrome c release, decreased mitochondrial membrane potential, accompany with the depletion of endoplasmic reticulum Ca2+ and elevation of cytosolic and mitochondrial Ca2+. Sequestration of cytosolic calcium with BAPTA-AM limited the response of podocyte apoptosis, while during the process the effect of AS-IV was also restrained. In contrast, elevation of cytosolic calcium with calcium ionophore ionomycin was depressed by AS-IV addition. Furthermore, inhibiting TRPC6 expression with SKF96365 or TRPC6 siRNA counteracted the beneficial effect of AS-IV. Our study provides further evidence to conclude the inhibitory effect of AS-IV to podocyte apoptosis is Ca2+-dependent. And the efficacy correlates with inhibiting TRPC6-mediated Ca2+ influx, and then cellular Ca2+ disturbance was coordinated.
Loss of podocytes is a hallmark of diabetic nephropathy, and a growing body of evidence indicates that podocytes are susceptible to pan class="Chemical">palmitic acid (PA). We have previously shown that AS-IV inhibited PA-induced podocyte apoptosis by activating sarcoendoplasmic reticulum Ca2+ ATPase (SERCA), which indicate calcium regulation may involve in the process. Immunofluorescence staining, Western blot and flow cytometry were used to measure the protective efficacy of AS-IV to ameliorate PA-induced ER stress and podocyte apoptosis. Meanwhile, AS-IV inhibited cytochrome c release, decreased mitochondrial membrane potential, accompany with the depletion of endoplasmic reticulum Ca2+ and elevation of cytosolic and mitochondrial Ca2+. Sequestration of cytosolic calcium with BAPTA-AM limited the response of podocyte apoptosis, while during the process the effect of AS-IV was also restrained. In contrast, elevation of cytosolic calcium with calcium ionophore ionomycin was depressed by AS-IV addition. Furthermore, inhibiting TRPC6 expression with SKF96365 or TRPC6 siRNA counteracted the beneficial effect of AS-IV. Our study provides further evidence to conclude the inhibitory effect of AS-IV to podocyte apoptosis is Ca2+-dependent. And the efficacy correlates with inhibiting TRPC6-mediated Ca2+ influx, and then cellular Ca2+ disturbance was coordinated.