Department of Endocrinology, Jinling Hospital, School of Medicine, Nanjing University, Nanjing, China.
Cell Biol Int. 2023 Apr;47(4):768-775. doi: 10.1002/cbin.11981. Epub 2023 Jan 30.
Ghrelin may have therapeutic value in mitigating insulin resistance and type 2 diabetes, based on which we further explore the action mechanism of ghrelin on islet cells in this research. In the course of experiments, MIN6 cells were induced by glucose and then treated with acylated or unacylated ghrelin. The effects of ghrelin on the viability, proliferation, apoptosis, and insulin release of high glucose-induced islet cells were detected by Cell Counting Kit-8, 5-ethynyl-2'-deoxyuridine, flow cytometry, and enzyme-linked immunosorbent assays, respectively. Meanwhile, cells were treated with LY294002 to explore whether and how the inhibited phosphoinositide 3-kinase-protein kinase B (PI3K-AKT) signaling pathway participated in the internal mechanism of ghrelin-regulating islet cells. Western blotting was performed to quantify the expression levels of Bcl-2, Bax, Cleaved caspase-3, PI3K, and AKT. As a result, ghrelin alleviated high glucose-induced suppression of viability and proliferation and promotion on apoptosis of MIN6 cells. Ghrelin also attenuated the inhibitory effects of high glucose on expression levels of PI3K-Akt signaling axis-related proteins and insulin release in MIN6 cells. Besides, ghrelin weakened the impacts of high glucose on boosting MIN6 cell apoptosis and hindering proliferation through the PI3K-Akt signaling axis. Collectively, ghrelin regulates the proliferation and apoptosis of high glucose-induced islet cells through the PI3K-Akt signaling pathway.
基于 ghrelin 可能具有减轻胰岛素抵抗和 2 型糖尿病的治疗价值，我们在本研究中进一步探索了 ghrelin 对胰岛细胞的作用机制。在实验过程中，用葡萄糖诱导 MIN6 细胞，然后用酰化或未酰化的 ghrelin 处理。通过细胞计数试剂盒-8、5-乙炔基-2'-脱氧尿苷、流式细胞术和酶联免疫吸附试验分别检测 ghrelin 对高糖诱导的胰岛细胞活力、增殖、凋亡和胰岛素释放的影响。同时，用 LY294002 处理细胞，以探讨被抑制的磷脂酰肌醇 3-激酶-蛋白激酶 B（PI3K-AKT）信号通路是否以及如何参与 ghrelin 调节胰岛细胞的内在机制。通过 Western blot 定量分析 Bcl-2、Bax、Cleaved caspase-3、PI3K 和 AKT 的表达水平。结果表明，ghrelin 减轻了高糖诱导的 MIN6 细胞活力和增殖抑制以及凋亡促进作用。ghrelin 还减弱了高糖对 MIN6 细胞中 PI3K-Akt 信号轴相关蛋白表达水平和胰岛素释放的抑制作用。此外，ghrelin 通过 PI3K-Akt 信号轴减弱了高糖对 MIN6 细胞凋亡的促进作用和增殖的抑制作用。总之，ghrelin 通过 PI3K-Akt 信号通路调节高糖诱导的胰岛细胞的增殖和凋亡。
