Tang Liang, Sun Qing, Luo Jinling, Peng Suying
Comprehensive Internal Medicine Department of High tech Industrial Park, Chongqing University Fuling Hospital, No. 32 Juye Avenue, High tech Zone, Fuling District, Chongqing, 408000, China.
Medical Clinical Nutrition Department, Chongqing Uniersity Fuling Hospital, No. 2 Gaosuntang Road, Fuling District, Chongqing, 408000, China.
Sci Rep. 2025 Mar 5;15(1):7768. doi: 10.1038/s41598-025-92716-z.
The management of hyperglycemia and lipid metabolism is pivotal for the treatment of type 2 diabetes mellitus (T2DM). Metformin hydrochloride (DMBG) remains the most widely prescribed medication for this condition. This study aimed to elucidate the effects and underlying mechanisms by which DMBG enhances glucolipid metabolism using both in vivo and in vitro experimental models. Animal models were established using high-fat diet (HFD)-fed mice, while cellular models utilized palmitic acid (PA)-induced HepG2 cells. In vivo, the impact of DMBG on glucolipid metabolism was evaluated through measurements of insulin and HbA1c levels, intraperitoneal glucose tolerance tests (ipGTT), intraperitoneal insulin tolerance tests (ipITT), as well as histological assessments with hematoxylin-eosin (HE) and Oil-red O staining. Mitochondrial function was assessed via biochemical assays of TBARS, SOD, ATP, and H2O2 levels in liver tissue, alongside determinations of mitochondrial membrane potential, ROS production, mtDNA content, and SIRT5 mRNA expression. For in vitro analysis, glucose consumption, mitochondrial membrane potential, ROS levels, and protein expressions of AMPK and PGC-1α were quantified in HepG2 cells. Western blotting and co-immunoprecipitation (co-IP) techniques were employed to investigate the mechanistic pathways involved. Treatment with DMBG resulted in reduced levels of free fatty acids, body weight, and fat mass, while also alleviating hyperglycemia and hepatic lipid accumulation in HFD-fed mice. Furthermore, DMBG restored impaired mitochondrial function in these animals and increased SIRT5 expression via AMPK activation. In vitro, DMBG mitigated PA-induced alterations in glucose consumption and mitochondrial dysfunction in HepG2 cells, an effect that was abrogated upon SIRT5 knockdown. Overexpression of SIRT5 led to enhanced trifunctional enzyme subunit-alpha (ECHA) desuccinylation at the K540 site, thereby increasing its activity. Collectively, our findings indicate that DMBG improves hepatic glucolipid metabolism through a mechanism involving SIRT5-mediated ECHA desuccinylation, potentially offering a new therapeutic avenue for T2DM.
高血糖和脂质代谢的管理对于2型糖尿病（T2DM）的治疗至关重要。盐酸二甲双胍（DMBG）仍然是治疗这种疾病最广泛使用的药物。本研究旨在通过体内和体外实验模型阐明DMBG增强糖脂代谢的作用及其潜在机制。使用高脂饮食（HFD）喂养的小鼠建立动物模型，而细胞模型则利用棕榈酸（PA）诱导的HepG2细胞。在体内，通过测量胰岛素和糖化血红蛋白（HbA1c）水平、腹腔内葡萄糖耐量试验（ipGTT）、腹腔内胰岛素耐量试验（ipITT）以及苏木精-伊红（HE）和油红O染色的组织学评估来评价DMBG对糖脂代谢的影响。通过对肝组织中丙二醛（TBARS）、超氧化物歧化酶（SOD）、三磷酸腺苷（ATP）和过氧化氢（H2O2）水平的生化分析，以及线粒体膜电位、活性氧（ROS）产生、线粒体DNA（mtDNA）含量和沉默信息调节因子5（SIRT5）mRNA表达的测定来评估线粒体功能。对于体外分析，在HepG2细胞中定量葡萄糖消耗、线粒体膜电位ROS水平以及腺苷酸活化蛋白激酶（AMPK）和过氧化物酶体增殖物激活受体γ共激活因子1α（PGC-1α）的蛋白表达。采用蛋白质印迹法和免疫共沉淀（co-IP）技术研究其中涉及的机制途径。用DMBG治疗可降低高脂饮食喂养小鼠的游离脂肪酸水平、体重和脂肪量，同时还可减轻高血糖和肝脏脂质蓄积。此外，DMBG恢复了这些动物受损的线粒体功能，并通过激活AMPK增加了SIRT5的表达。在体外，DMBG减轻了PA诱导的HepG2细胞葡萄糖消耗改变和线粒体功能障碍，这种作用在SIRT5基因敲低后被消除。SIRT5的过表达导致三功能酶亚基α（ECHA）在K540位点的去琥珀酰化增强，从而增加其活性。总的来说，我们的研究结果表明，DMBG通过一种涉及SIRT5介导的ECHA去琥珀酰化的机制改善肝脏糖脂代谢，这可能为2型糖尿病提供一条新的治疗途径。
