Different downstream signalling of CCK1 receptors regulates distinct functions of CCK in pancreatic beta cells
Different downstream signalling of CCK1 receptors regulates distinct functions of CCK in pancreatic beta cells
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CCK1 受体的不同下游信号传导调节胰腺 β 细胞中 CCK 的不同功能。
DOI：
10.1111/bph.13271
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发表时间：
2015-11-01
影响因子：
7.3
通讯作者：
Sun, Jin-peng
中科院分区：
文献类型：
--
作者：
Ning, Shang-lei;Zheng, Wen-shuai;Sun, Jin-peng
背景和目的胆囊收缩素（CCK）由肠道 I 细胞分泌，调节重要的代谢功能。在胰岛中，CCK 主要通过 CCK1 受体控制 β 细胞功能，但胰腺 β 细胞中这些受体下游的信号传导途径尚未明确。 实验方法 使用 Hoechst-33342 染色、TUNEL 测定和 Annexin-V-FITC/PI 染色评估胰腺 β 细胞凋亡中的凋亡。使用 ELISA 监测胰岛素分泌和第二信使产生。通过蛋白质印迹法测定蛋白质和磷蛋白水平。通过葡萄糖耐量试验来检查 CCK-8s 在链脲佐菌素诱导的糖尿病小鼠中的功能。 主要结果 硫酸化羧基末端八肽 CCK26-33 酰胺 (CCK-8s) 激活 CCK1 受体并诱导 IP3 和 cAMP 的积累。虽然低血糖条件下 CCK-8s 诱导的胰岛素分泌需要 G(q)-PLC-IP3 信号传导，但高血糖条件下 G(s)-PKA/Epac 信号传导对 CCK-8s 介导的胰岛素分泌贡献更大。 CCK-8 还促进胰腺 β 细胞中 CCK1 受体/-arrestin-1 复合物的形成。使用 -arrestin-1 敲除小鼠，我们证明 -arrestin-1 是 CCK-8s 介导的胰岛素分泌及其对胰腺 β 细胞凋亡的保护作用的关键介质。 -arrestin-1 的抗凋亡作用通过细胞质晚期 ERK 激活发生，从而激活 90-kDa 核糖体 S6 激酶磷酸化 Bcl-2 家族蛋白途径。结论和意义不同 CCK1 受体激活的下游信号传导途径在调节胰腺 β 细胞的不同功能中的知识可用于识别偏向的 CCK1 受体配体，用于开发新的抗糖尿病药物。
Background and PurposeCholecystokinin (CCK) is secreted by intestinal I cells and regulates important metabolic functions. In pancreatic islets, CCK controls beta cell functions primarily through CCK1 receptors, but the signalling pathways downstream of these receptors in pancreatic beta cells are not well defined.Experimental ApproachApoptosis in pancreatic beta cell apoptosis was evaluated using Hoechst-33342 staining, TUNEL assays and Annexin-V-FITC/PI staining. Insulin secretion and second messenger production were monitored using ELISAs. Protein and phospho-protein levels were determined by Western blotting. A glucose tolerance test was carried out to examine the functions of CCK-8s in streptozotocin-induced diabetic mice.Key ResultsThe sulfated carboxy-terminal octapeptide CCK26-33 amide (CCK-8s) activated CCK1 receptors and induced accumulation of both IP3 and cAMP. Whereas G(q)-PLC-IP3 signalling was required for the CCK-8s-induced insulin secretion under low-glucose conditions, G(s)-PKA/Epac signalling contributed more strongly to the CCK-8s-mediated insulin secretion in high-glucose conditions. CCK-8s also promoted formation of the CCK1 receptor/-arrestin-1 complex in pancreatic beta cells. Using -arrestin-1 knockout mice, we demonstrated that -arrestin-1 is a key mediator of both CCK-8s-mediated insulin secretion and of its the protective effect against apoptosis in pancreatic beta cells. The anti-apoptotic effects of -arrestin-1 occurred through cytoplasmic late-phase ERK activation, which activates the 90-kDa ribosomal S6 kinase-phospho-Bcl-2-family protein pathway.Conclusions and ImplicationsKnowledge of different CCK1 receptor-activated downstream signalling pathways in the regulation of distinct functions of pancreatic beta cells could be used to identify biased CCK1 receptor ligands for the development of new anti-diabetic drugs.