Lan Shan-Fen, Yang Zhen-Hua, Feng Li, Wen Yu-Ting, Chen Kun-Ni, Fan Lang-Lin, Wang Ming-Jun, Liu Wen-Ting
Department of Nephrology, First Affiliated Hospital of Guangxi Medical University, Nanning, 530022, China.
Acta Diabetol. 2025 Feb 25. doi: 10.1007/s00592-025-02476-5.
Mitochondrial dysfunction leading to impaired energy metabolism has been recognized as a pivotal factor contributing to renal tubular epithelial cells (RTECs) damage in the context of dyslipidemia conditions in diabetic kidney disease (DKD). The primary objective of this study is to elucidate the role and underlying mechanism of the proto-oncogene Metadherin (MTDH) in mediating mitochondrial damage within this specific pathological context in vitro.
The expression of MTDH in RTECs was modulated by transfecting small interfering RNA and plasmid, while palmitic acid (PA) was employed to simulate diabetic lipid metabolism disorder. Mitochondrial damage was evaluated by examining various parameters including mitochondrial morphology, membrane potential, reactive oxygen species (ROS) production, adenosine triphosphate (ATP) production, as well as morphological and structural alterations. Additionally, Carnitine acetyltransferase (CrAT) expression was assessed using Western blotting and quantitative real-time polymerase chain reaction, and CrAT activity was quantified.
MTDH expression was upregulated in PA-induced RTECs, while CrAT expression and activity were inhibited. Downregulation of MTDH mitigated PA-induced mitochondrial damage, as demonstrated by the preservation of mitochondrial membrane potential, reduction in mitochondrial ROS production, prevention of ATP depletion, and maintenance of mitochondrial structure. This was accompanied by an upregulation in CrAT expression and activity. Conversely, overexpression of MTDH exacerbated mitochondrial dysfunction by impairing membrane potential, augmenting mitochondrial ROS production, inhibiting ATP synthesis, and suppressing CrAT expression and activity.
In the context of dyslipidemia conditions, MTDH is upregulated and suppresses the expression and activity of CrAT in RTECs, thereby inducing mitochondrial dysfunction and perturbing energy metabolism. These alterations exacerbate the injury to RTECs, consequently promoting the progression of DKD.
线粒体功能障碍导致能量代谢受损，已被认为是糖尿病肾病（DKD）血脂异常情况下导致肾小管上皮细胞（RTECs）损伤的关键因素。本研究的主要目的是在体外阐明原癌基因Metadherin（MTDH）在这种特定病理背景下介导线粒体损伤的作用及潜在机制。
通过转染小干扰RNA和质粒来调节RTECs中MTDH的表达，同时使用棕榈酸（PA）模拟糖尿病脂质代谢紊乱。通过检测包括线粒体形态、膜电位、活性氧（ROS）产生、三磷酸腺苷（ATP）产生以及形态和结构改变等各种参数来评估线粒体损伤。此外，使用蛋白质免疫印迹法和定量实时聚合酶链反应评估肉碱乙酰转移酶（CrAT）的表达，并对CrAT活性进行定量。
在PA诱导的RTECs中MTDH表达上调，而CrAT表达和活性受到抑制。MTDH的下调减轻了PA诱导的线粒体损伤，表现为线粒体膜电位的保留、线粒体ROS产生的减少、ATP消耗的预防以及线粒体结构的维持。这伴随着CrAT表达和活性的上调。相反，MTDH的过表达通过损害膜电位、增加线粒体ROS产生、抑制ATP合成以及抑制CrAT表达和活性而加剧线粒体功能障碍。
在血脂异常情况下，MTDH上调并抑制RTECs中CrAT的表达和活性，从而诱导线粒体功能障碍并扰乱能量代谢。这些改变加剧了对RTECs的损伤，进而促进DKD的进展。
