Department of Internal Medicine, Chonnam National University Medical School, Gwangju 61469, Korea.
Int J Mol Sci. 2019 Jul 10;20(14):3386. doi: 10.3390/ijms20143386.
G-protein-coupled receptor 40 (GPR40) has an anti-apoptotic effect in pancreatic β-cells. However, its role in renal tubular cell apoptosis remains unclear. To explore the role of GPR40 in renal tubular apoptosis, a two-week unilateral ureteral obstruction (UUO) mouse model was used. The protein expression of GPR40 was decreased, while the Bax/Bcl-2 protein expression ratio, the expression of tumor necrosis factor (TNF)-α mRNA, and angiotensin II type 1 receptor (AT1R) protein were increased in mice with UUO. In vitro, pretreatment of rat proximal tubular (NRK52E) cells with GW9508, a GPR40 agonist, attenuated the decreased cell viability, increased the Bax/Bcl-2 protein expression ratio, increased protein expression of cleaved caspase-3 and activated the nuclear translocation of nuclear factor-κB (NF-κB) p65 subunit induced by TNF-α treatment. TNF-α treatment significantly increased the expression of AT1R protein and the generation of reactive oxygen species (ROS), whereas GW9508 treatment markedly reversed these effects. Pretreatment with GW1100, a GPR40 antagonist, or silencing of GPR40 in NRK52E cells promoted the increased expression of the cleaved caspase-3 protein by TNF-α treatment. Our results demonstrate that decreased expression of GPR40 is associated with apoptosis via TNF-α and AT1R in the ureteral obstructed kidney. The activation of GPR40 attenuates TNF-α-induced apoptosis by inhibiting AT1R expression and ROS generation through regulation of the NF-κB signaling pathway.
G 蛋白偶联受体 40（GPR40）在胰岛β细胞中具有抗凋亡作用。然而，其在肾小管细胞凋亡中的作用尚不清楚。为了探讨 GPR40 在肾小管细胞凋亡中的作用，我们建立了两周单侧输尿管梗阻（UUO）小鼠模型。结果显示，UUO 小鼠肾脏中 GPR40 蛋白表达降低，而 Bax/Bcl-2 蛋白表达比值、肿瘤坏死因子（TNF）-α mRNA 的表达和血管紧张素 II 型 1 受体（AT1R）蛋白表达增加。在体外，用 GPR40 激动剂 GW9508 预处理大鼠近端肾小管（NRK52E）细胞，可减轻 TNF-α处理导致的细胞活力降低、Bax/Bcl-2 蛋白表达比值增加、caspase-3 蛋白表达增加和核转录因子-κB（NF-κB）p65 亚基核转位激活。TNF-α处理可显著增加 AT1R 蛋白表达和活性氧（ROS）的产生，而 GW9508 处理可明显逆转这些作用。GW1100（GPR40 拮抗剂）预处理或 NRK52E 细胞中 GPR40 的沉默可促进 TNF-α处理增加 cleaved caspase-3 蛋白的表达。我们的研究结果表明，在梗阻肾脏中，GPR40 的表达降低与 TNF-α和 AT1R 诱导的细胞凋亡有关。GPR40 的激活通过抑制 AT1R 表达和 ROS 生成，通过调节 NF-κB 信号通路，减轻 TNF-α诱导的细胞凋亡。
