Rodrigues Alice C, Spagnol Alexandre R, Frias Flávia de Toledo, de Mendonça Mariana, Araújo Hygor N, Guimarães Dimitrius, Silva William J, Bolin Anaysa Paola, Murata Gilson Masahiro, Silveira Leonardo
Department of Pharmacology, Instituto de Ciencias Biomedicas, Universidade de São Paulo, São Paulo, Brazil.
Obesity and Comorbidities Research Center (OCRC), Campinas, Brazil.
Front Physiol. 2021 Jul 6;12:676265. doi: 10.3389/fphys.2021.676265. eCollection 2021.
The role of microRNAs in metabolic diseases has been recognized and modulation of them could be a promising strategy to treat obesity and obesity-related diseases. The major purpose of this study was to test the hypothesis that intramuscular miR-1 precursor replacement therapy could improve metabolic parameters of mice fed a high-fat diet. To this end, we first injected miR-1 precursor intramuscularly in high-fat diet-fed mice and evaluated glucose tolerance, insulin sensitivity, and adiposity. miR-1-treated mice did not lose weight but had improved insulin sensitivity measured by insulin tolerance test. Next, using an model of insulin resistance by treating C2C12 cells with palmitic acid (PA), we overexpressed miR-1 and measured p-Akt content and the transcription levels of a protein related to fatty acid oxidation. We found that miR-1 could not restore insulin sensitivity in C2C12 cells, as indicated by p-Akt levels and that miR-1 increased expression of and in PA-treated cells, suggesting a possible role of miR-1 in mitochondrial respiration. Finally, we analyzed mitochondrial oxygen consumption in primary skeletal muscle cells treated with PA and transfected with or without miR-1 mimic. PA-treated cells showed reduced basal respiration, oxygen consumption rate-linked ATP production, maximal and spare capacity, and miR-1 overexpression could prevent impairments in mitochondrial respiration. Our data suggest a role of miR-1 in systemic insulin sensitivity and a new function of miR-1 in regulating mitochondrial respiration in skeletal muscle.
微小RNA在代谢性疾病中的作用已得到认可，对其进行调控可能是治疗肥胖及肥胖相关疾病的一种有前景的策略。本研究的主要目的是验证以下假设：肌肉内miR-1前体替代疗法可改善高脂饮食喂养小鼠的代谢参数。为此，我们首先对高脂饮食喂养的小鼠进行肌肉内注射miR-1前体，并评估其葡萄糖耐量、胰岛素敏感性和肥胖程度。经miR-1处理的小鼠体重未减轻，但通过胰岛素耐量试验测得其胰岛素敏感性有所改善。接下来，我们利用棕榈酸（PA）处理C2C12细胞建立胰岛素抵抗模型，过表达miR-1并检测p-Akt含量以及与脂肪酸氧化相关的一种蛋白质的转录水平。我们发现，p-Akt水平表明miR-1无法恢复C2C12细胞中的胰岛素敏感性，并且miR-1增加了PA处理细胞中[此处原文缺失相关蛋白名称]和[此处原文缺失相关蛋白名称]的表达，这表明miR-1在线粒体呼吸中可能发挥作用。最后，我们分析了用PA处理并转染有或无miR-1模拟物的原代骨骼肌细胞中的线粒体氧消耗情况。PA处理的细胞基础呼吸、与氧消耗率相关的ATP产生、最大及备用能力均降低，而miR-1过表达可防止线粒体呼吸受损。我们的数据表明miR-1在全身胰岛素敏感性方面发挥作用，并且miR-1在调节骨骼肌线粒体呼吸方面具有新功能。
