Zhong Xiaodan, Li Yu, Xie Yang, Zhang Yueqi, Wang Mengwen, Jiang Hongcheng, Liu Zixuan, Dai Lei, Li Lina, Wang Honghui, Madhusudhan Thati, Zeng Hesong, Wang Hongjie
Department of Cardiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, Hubei, China; Hubei Provincial Engineering Research Center of Vascular Interventional Therapy, Wuhan, 430030, Hubei, China.
Department of Cardiology, Fuwai Yunnan Hospital, Chinese Academy of Medical Sciences, Affiliated Cardiovascular Hospital of Kunming Medical University, Kunming, 650102, Yunnan, China.
Eur J Pharmacol. 2025 Sep 15;1003:177956. doi: 10.1016/j.ejphar.2025.177956. Epub 2025 Jul 16.
Diabetic cardiomyopathy (DCM) is a common complication of diabetes mellitus and frequently progresses to heart failure. Although the deubiquitinase OTUB1 has demonstrated protective effects in DCM, the upstream regulatory mechanisms governing its expression and their influence on mitochondrial function remain unclear.
We used a short-term insulinopenic diabetic mouse model supplemented with exogenous protein C (PC) to investigate the role of activated protein C (aPC) in regulating OTUB1 during early-stage DCM. A thrombomodulin-mutant (TM) mouse model, which limits endogenous PC activation, was employed to assess long-term effects. Additionally, a microRNA miR-493-5p sponge was delivered via recombinant adeno-associated virus (rAAV) to evaluate the therapeutic potential of miR-493-5p inhibition.
Exogenous PC supplementation preserved cardiac function and restored OTUB1 protein levels in early-stage DCM without affecting Otub1 mRNA expression. In contrast, TM mice exhibited exacerbated cardiac dysfunction and reduced OTUB1 protein abundance. Mechanistically, we identified miR-493-5p as a direct translational repressor of OTUB1, which was upregulated in diabetic hearts and downregulated by aPC through endothelial protein C receptor-protease-activated receptor 1 signaling. Both in vitro and in vivo experiments confirmed that miR-493-5p impairs OTUB1-mediated mitochondrial function, resulting in cardiomyocyte apoptosis. Inhibition of miR-493-5p via rAAV-sponge delivery restored OTUB1 levels, improved mitochondrial morphology, and significantly enhanced cardiac function in diabetic mice.
Our findings identify the aPC/miR-493-5p/OTUB1 axis as a critical regulatory pathway in DCM pathogenesis. Targeting this axis may represent a promising therapeutic strategy for preserving mitochondrial integrity and preventing diabetic cardiac dysfunction.
糖尿病性心肌病（DCM）是糖尿病的常见并发症，常进展为心力衰竭。尽管去泛素化酶OTUB1已在DCM中显示出保护作用，但其表达的上游调控机制及其对线粒体功能的影响仍不清楚。
我们使用补充外源性蛋白C（PC）的短期胰岛素缺乏型糖尿病小鼠模型，研究活化蛋白C（aPC）在早期DCM中调节OTUB1的作用。采用限制内源性PC激活的血栓调节蛋白突变体（TM）小鼠模型评估长期影响。此外，通过重组腺相关病毒（rAAV）递送微小RNA miR-493-5p海绵，以评估抑制miR-493-5p的治疗潜力。
补充外源性PC可保留早期DCM的心脏功能并恢复OTUB1蛋白水平，而不影响Otub1 mRNA表达。相比之下，TM小鼠表现出心脏功能障碍加剧和OTUB1蛋白丰度降低。机制上，我们确定miR-493-5p是OTUB1的直接翻译抑制因子，其在糖尿病心脏中上调，并通过内皮蛋白C受体-蛋白酶激活受体1信号通路被aPC下调。体外和体内实验均证实，miR-493-5p损害OTUB1介导的线粒体功能，导致心肌细胞凋亡。通过rAAV-海绵递送抑制miR-493-5p可恢复OTUB1水平，改善线粒体形态，并显著增强糖尿病小鼠的心脏功能。
我们的研究结果确定aPC/miR-493-5p/OTUB1轴是DCM发病机制中的关键调控途径。靶向该轴可能是一种有前景的治疗策略，可维持线粒体完整性并预防糖尿病性心脏功能障碍。
