Guo N-F, Qiu Z, Chen X-L, Chen X, Huang J-B, Liu J
Department of Nephrology, The Affiliated Hospital of Nantong University, Nantong, China.
Eur Rev Med Pharmacol Sci. 2020 May;24(9):4954-4962. doi: 10.26355/eurrev_202005_21186.
This study aimed to investigate the effects of prostaglandin E2 receptor subtypes 1 (EP1) and 2 (EP2) on endoplasmic reticulum (ER) stress induced by TGF-β1 in mouse mesangial cells (MCs) and to explore its potential mechanisms.
Mouse mesangial cells were isolated and cultured. EP-siRNAs were transfected into mesangial cells for silencing EP1 and EP2. Mesangial cell proliferation was assessed by the CCK-8 method. Expression of PGE2 was measured by enzyme-linked immunosorbent assay (ELISA). GRP78, TRPC1, ERK1/2, and phospho-ERK1/2 levels were examined by Western blot.
TGF-β1 induced mesangial cell proliferation and increased PGE2 secretion. Besides, TGF-β1 significantly upregulated GRP78 and TRPC1 expression at the protein level. Phospho-ERK1/2 protein amounts were also increased (p<0.05). Compared with the TGF-β1 group, cell proliferation in the EP1-siRNA+TGF-β1 group was reduced, while GRP78, TRPC1, and ERK1/2 protein amounts were downregulated (p<0.05). EP1 agonist significantly enhanced above changes and their activities (p<0.05). EP1 antagonist significantly attenuated the above changes (p<0.05). Compared with TGF-β1 group, cell proliferation in EP2-siRNA+TGF-β1 group was increased, while GRP78, TRPC1, and ERK1/2 protein amounts were increased (p<0.05). EP2 agonist significantly attenuated the above changes (p<0.05).
EP1 receptor may increase TGF-β1-induced cell damage by increasing the activities of GRP78, TRPC1, and ERK1/2 via ER stress. Meanwhile, the EP2 receptor may reduce TGF-β1-induced cell damage by suppressing GRP78, TRPC1, and ERK1/2 activities, also via ER stress. EP1 inhibition and EP2 stimulation may be a therapeutic option for delaying renal fibrosis.
本研究旨在探讨前列腺素E2受体亚型1（EP1）和2（EP2）对转化生长因子-β1（TGF-β1）诱导的小鼠系膜细胞（MCs）内质网（ER）应激的影响，并探索其潜在机制。
分离并培养小鼠系膜细胞。将EP-siRNAs转染至系膜细胞以沉默EP1和EP2。采用CCK-8法评估系膜细胞增殖。通过酶联免疫吸附测定（ELISA）检测PGE2的表达。通过蛋白质印迹法检测葡萄糖调节蛋白78（GRP78）、瞬时受体电位通道蛋白1（TRPC1）、细胞外信号调节激酶1/2（ERK1/2）及磷酸化ERK1/2的水平。
TGF-β1诱导系膜细胞增殖并增加PGE2分泌。此外，TGF-β1在蛋白水平显著上调GRP78和TRPC1的表达。磷酸化ERK1/2蛋白量也增加（p<0.05）。与TGF-β1组相比，EP1-siRNA+TGF-β1组细胞增殖减少，而GRP78、TRPC1和ERK1/2蛋白量下调（p<0.05）。EP1激动剂显著增强上述变化及其活性（p<0.05）。EP1拮抗剂显著减弱上述变化（p<0.05）。与TGF-β1组相比，EP2-siRNA+TGF-β1组细胞增殖增加，而GRP78、TRPC1和ERK1/2蛋白量增加（p<0.05）。EP2激动剂显著减弱上述变化（p<0.05）。
EP1受体可能通过内质网应激增加GRP78、TRPC1和ERK1/2的活性，从而加重TGF-β1诱导的细胞损伤。同时，EP2受体也可能通过内质网应激抑制GRP78、TRPC1和ERK1/2的活性，减轻TGF-β1诱导的细胞损伤。抑制EP1和刺激EP2可能是延缓肾纤维化的一种治疗选择。
