Lei Yu, Yang Hui-Ying, Meng Nuo, Qin Ying-Ying, Xu Meng-Tao, Xiang Xue-Lian, Liu Li, Tang Guo-Du
Department of Gastroenterology, The First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi 530021, P.R. China.
Exp Ther Med. 2024 Feb 19;27(4):147. doi: 10.3892/etm.2024.12435. eCollection 2024 Apr.
The mitochondrial calcium uniporter (MCU) is a major protein for the uptake of mitochondrial calcium to regulate intracellular energy metabolism, including processes such as mitophagy. The present study investigated the effect of the MCU on mitophagy in pancreatic ductal epithelial cells (PDECs) in acute pancreatitis (AP) . The normal human PDECs (HPDE6-C7) were treated with caerulein (CAE) to induce AP-like changes, with or without ruthenium red to inhibit the MCU. The mitochondrial membrane potentials (MMPs) and mitochondrial Ca levels were analyzed by fluorescence. The expression levels of MCU, LC3, p62, and translocase of the outer mitochondrial membrane complex subunit 20 (TOMM20), putative kinase 1 (PINK1), and Parkin were measured by western blotting and immunofluorescence. Mitophagy was observed by confocal fluorescence microscopy and transmission electron microscopy. The results showed that CAE increased the MCU protein expression, mitochondrial Ca levels, MMP depolarization and the protein expression of mitophagy markers including the LC3II/I ratio, PINK1, and Parkin. CAE decreased the protein expression of p62 and TOMM20, and promoted the formation of mitophagosomes in HPDE6-C7 cells. Notably, changes in these markers were reversed by inhibiting the MCU. In conclusion, an activated MCU may promote mitophagy by regulating the PINK1/Parkin pathway in PDECs in AP.
线粒体钙单向转运体（MCU）是一种主要的蛋白质，负责摄取线粒体钙以调节细胞内能量代谢，包括线粒体自噬等过程。本研究调查了MCU对急性胰腺炎（AP）中胰腺导管上皮细胞（PDEC）线粒体自噬的影响。将正常人PDEC（HPDE6-C7）用雨蛙素（CAE）处理以诱导类似AP的变化，同时添加或不添加钌红以抑制MCU。通过荧光分析线粒体膜电位（MMP）和线粒体钙水平。通过蛋白质印迹法和免疫荧光法检测MCU、微管相关蛋白1轻链3（LC3）、p62、外膜线粒体膜转位酶复合物亚基20（TOMM20）、假定激酶1（PINK1）和帕金蛋白的表达水平。通过共聚焦荧光显微镜和透射电子显微镜观察线粒体自噬。结果表明，CAE增加了MCU蛋白表达、线粒体钙水平、MMP去极化以及包括LC3II/I比率、PINK1和帕金蛋白在内的线粒体自噬标志物的蛋白表达。CAE降低了p62和TOMM20的蛋白表达，并促进了HPDE6-C7细胞中线粒体自噬体的形成。值得注意的是，通过抑制MCU可逆转这些标志物的变化。总之，活化的MCU可能通过调节AP中PDEC的PINK1/帕金蛋白途径促进线粒体自噬。
