PDZD8 Augments Endoplasmic Reticulum-Mitochondria Contact and Regulates Ca2+ Dynamics and Cypd Expression to Induce Pancreatic β-Cell Death during Diabetes.

IF 6.8 2区医学 Q1 ENDOCRINOLOGY & METABOLISM

Diabetes & Metabolism Journal Pub Date : 2024-07-29 DOI:10.4093/dmj.2023.0275

Yongxin Liu, Yongqing Wei, Xiaolong Jin, Hongyu Cai, Qianqian Chen, Xiujuan Zhang

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引用次数: 0

Abstract

Background: Diabetes mellitus (DM) is a chronic metabolic disease that poses serious threats to human physical and mental health worldwide. The PDZ domain-containing 8 (PDZD8) protein mediates mitochondria-associated endoplasmic reticulum (ER) membrane (MAM) formation in mammals. We explored the role of PDZD8 in DM and investigated its potential mechanism of action.

Methods: High-fat diet (HFD)- and streptozotocin-induced mouse DM and palmitic acid (PA)-induced insulin 1 (INS-1) cell models were constructed. PDZD8 expression was detected using immunohistochemistry, quantitative real-time polymerase chain reaction (qRT-PCR), and Western blotting. MAM formation, interactions between voltage-dependent anion-selective channel 1 (VDAC1) and inositol 1,4,5-triphosphate receptor type 1 (IP3R1), pancreatic β-cell apoptosis and proliferation were detected using transmission electron microscopy (TEM), proximity ligation assay (PLA), terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay, immunofluorescence staining, and Western blotting. The mitochondrial membrane potential, cell apoptosis, cytotoxicity, and subcellular Ca2+ localization in INS-1 cells were detected using a JC-1 probe, flow cytometry, and an lactate dehydrogenase kit.

Results: PDZD8 expression was up-regulated in the islets of HFD mice and PA-treated pancreatic β-cells. PDZD8 knockdown markedly shortened MAM perimeter, suppressed the expression of MAM-related proteins IP3R1, glucose-regulated protein 75 (GRP75), and VDAC1, inhibited the interaction between VDAC1 and IP3R1, alleviated mitochondrial dysfunction and ER stress, reduced the expression of ER stress-related proteins, and decreased apoptosis while increased proliferation of pancreatic β-cells. Additionally, PDZD8 knockdown alleviated Ca2+ flow into the mitochondria and decreased cyclophilin D (Cypd) expression. Cypd overexpression alleviated the promoting effect of PDZD8 knockdown on the apoptosis of β-cells.

Conclusion: PDZD8 knockdown inhibited pancreatic β-cell death in DM by alleviated ER-mitochondria contact and the flow of Ca2+ into the mitochondria.

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PDZD8 可增强内质网-线粒体接触并调节 Ca2+ 动态和 Cypd 表达，从而诱导糖尿病期间胰腺 β 细胞死亡。

背景：糖尿病（DM）是一种慢性代谢性疾病，严重威胁着全世界人类的身心健康。在哺乳动物体内，含 PDZ 结构域的 8 (PDZD8) 蛋白介导线粒体相关内质网 (ER) 膜 (MAM) 的形成。方法：构建高脂饮食（HFD）和链脲佐菌素诱导的小鼠 DM 和棕榈酸（PA）诱导的胰岛素 1（INS-1）细胞模型。采用免疫组织化学、实时定量聚合酶链反应（qRT-PCR）和 Western 印迹法检测 PDZD8 的表达。利用透射电子显微镜（TEM）、近距离连接试验（PLA）、末端脱氧核苷酸转移酶 dUTP 缺口标记（TUNEL）试验、免疫荧光染色和 Western 印迹法检测了 MAM 的形成、电压依赖性阴离子选择性通道 1（VDAC1）与 1,4,5-三磷酸肌醇受体 1 型（IP3R1）之间的相互作用、胰腺 β 细胞的凋亡和增殖。使用 JC-1 探针、流式细胞仪和乳酸脱氢酶试剂盒检测 INS-1 细胞的线粒体膜电位、细胞凋亡、细胞毒性和亚细胞 Ca2+ 定位：结果：PDZD8在HFD小鼠的胰岛和PA处理的胰腺β细胞中表达上调。PDZD8 的敲除明显缩短了 MAM 的周长，抑制了 MAM 相关蛋白 IP3R1、葡萄糖调节蛋白 75 (GRP75) 和 VDAC1 的表达，抑制了 VDAC1 和 IP3R1 之间的相互作用，缓解了线粒体功能障碍和 ER 应激，降低了 ER 应激相关蛋白的表达，减少了胰腺 β 细胞的凋亡，同时增加了增殖。此外，PDZD8 的敲除减轻了进入线粒体的 Ca2+ 流量，并降低了环嗜蛋白 D（Cypd）的表达。Cypd的过表达减轻了PDZD8敲除对β细胞凋亡的促进作用：结论：PDZD8基因敲除通过减轻ER-线粒体接触和Ca2+流入线粒体，抑制了DM中胰腺β细胞的死亡。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Diabetes & Metabolism Journal Medicine-Endocrinology, Diabetes and Metabolism

CiteScore

10.40

自引率

6.80%

发文量

审稿时长

52 weeks

期刊介绍： The aims of the Diabetes & Metabolism Journal are to contribute to the cure of and education about diabetes mellitus, and the advancement of diabetology through the sharing of scientific information on the latest developments in diabetology among members of the Korean Diabetes Association and other international societies. The Journal publishes articles on basic and clinical studies, focusing on areas such as metabolism, epidemiology, pathogenesis, complications, and treatments relevant to diabetes mellitus. It also publishes articles covering obesity and cardiovascular disease. Articles on translational research and timely issues including ubiquitous care or new technology in the management of diabetes and metabolic disorders are welcome. In addition, genome research, meta-analysis, and randomized controlled studies are welcome for publication. The editorial board invites articles from international research or clinical study groups. Publication is determined by the editors and peer reviewers, who are experts in their specific fields of diabetology.