Bian Yongsheng, Yang Yimei, Chen Jun, Liu Jian, Tao Yan, Liu Zhongjie, Huang Lijin
Department of Neurosurgery, The Third Affiliated Hospital of Southern Medical University, Guangzhou, Guangdong Province 510660, People's Republic of China.
Department of Neurosurgery, Guangdong Provincial Hospital of Chinese Medicine, The Second Affiliated Hospital of Guangzhou University of Chinese Medicine, Guangzhou, Guangdong Province 510030, People's Republic of China.
Neuroscience. 2025 May 7;573:286-299. doi: 10.1016/j.neuroscience.2025.03.052. Epub 2025 Mar 24.
Neuropathic pain often complicates diabetes progression, yet the pathogenic mechanisms are poorly understood. Defective mitophagy is linked to various diabetic complications like nephropathy, cardiomyopathy, and retinopathy. To investigate the molecular basis of hyperglycemia-induced painful diabetic neuropathy (PDN), we examined the effect of high glucose on the PTEN-induced kinase 1 (PINK1)/Parkin RBR E3 ubiquitin protein ligase (Parkin)-mediated mitophagy pathway in ND7/23 cells. Cells were treated with different glucose concentrations (25, 50, 75 mM) for various durations (24, 48, 72 h). Additionally, cells were exposed to high glucose (50 mM) with or without 100 nM rapamycin (a mitophagy enhancer) for 48 h, or transfected with PINK1 siRNA. We assessed protein levels of mitophagy-related genes (PINK1, Parkin, P62, LC3B) and apoptotic markers (cleaved-Caspase3) via Western blotting. High glucose significantly reduced the expression of autophagy-related proteins PINK1 and Parkin in a time- and concentration-dependent manner compared to controls. Rapamycin counteracted the inhibitory effects of high glucose on PINK1/Parkin-mediated mitophagy, while PINK1 siRNA transfection showed similar outcomes, confirming the inhibitory impact of high glucose on mitophagy. Moreover, high glucose induced apoptosis by suppressing PINK1/Parkin-mediated mitophagy, causing cytotoxic effects in ND7/23 cells which is derived from the fusion of mouse neuroblastoma cells and rat dorsal root ganglion (DRG) cells. Our findings suggest that hyperglycemia-induced disruption of the PINK1/Parkin mitophagy pathway impairs mitochondrial homeostasis, leading to apoptosis. Therefore, targeting PINK1 pathway activation or restoring mitophagy might be a promising therapeutic strategy for PDN treatment.
神经性疼痛常使糖尿病病情复杂化，但其致病机制尚不清楚。线粒体自噬缺陷与多种糖尿病并发症如肾病、心肌病和视网膜病变有关。为了研究高血糖诱导的疼痛性糖尿病神经病变（PDN）的分子基础，我们检测了高糖对ND7/23细胞中PTEN诱导激酶1（PINK1）/帕金RBR E3泛素蛋白连接酶（Parkin）介导的线粒体自噬途径的影响。细胞用不同葡萄糖浓度（25、50、75 mM）处理不同时间（24、48、72小时）。此外，细胞暴露于含或不含100 nM雷帕霉素（一种线粒体自噬增强剂）的高糖（50 mM）环境中48小时，或转染PINK1小干扰RNA（siRNA）。我们通过蛋白质免疫印迹法评估线粒体自噬相关基因（PINK1、Parkin、P62、LC3B）和凋亡标志物（裂解型半胱天冬酶3）的蛋白水平。与对照组相比，高糖以时间和浓度依赖性方式显著降低自噬相关蛋白PINK1和Parkin的表达。雷帕霉素抵消了高糖对PINK1/Parkin介导的线粒体自噬的抑制作用，而PINK1 siRNA转染显示了相似的结果，证实了高糖对线粒体自噬的抑制作用。此外，高糖通过抑制PINK1/Parkin介导的线粒体自噬诱导细胞凋亡，在由小鼠神经母细胞瘤细胞和大鼠背根神经节（DRG）细胞融合而成的ND7/23细胞中产生细胞毒性作用。我们的研究结果表明，高血糖诱导的PINK1/Parkin线粒体自噬途径破坏损害了线粒体稳态，导致细胞凋亡。因此，靶向激活PINK1途径或恢复线粒体自噬可能是治疗PDN的一种有前景的治疗策略。
