The circadian clock is closely related to the development of diabetes mellitus and cardiovascular disease, and disruption of the circadian clock exacerbates myocardial ischaemia/reperfusion injury (MI/RI). HDAC3 is a key component of the circadian negative feedback loop that controls the expression pattern of the circadian nuclear receptor Rev-erbα to maintain the stability of circadian genes such as BMAL1. However, the mechanism by which the HDAC3-orchestrated Rev-erbα/BMAL1 pathway increases MI/RI in diabetes and its relationship with mitophagy have yet to be elucidated. Here, we observed that the clock genes Rev-erbα, BMAL1, and C/EBPβ oscillations were altered in the hearts of rats with streptozotocin (STZ)-induced diabetes, with upregulated HDAC3 expression. Oscillations of Rev-erbα and BMAL1 were rapidly attenuated in diabetic MI/R hearts versus non-diabetic I/RI hearts, in accordance with impaired and rhythm-disordered circadian-dependent mitophagy that increased injury. Genetic knockdown of HDAC3 significantly attenuated diabetic MI/RI by mediating the Rev-erbα/BMAL1 circadian pathway to recover mitophagy. Primary cardiomyocytes with or without HDAC3 siRNA and Rev-erbα siRNA were exposed to hypoxia/reoxygenation (H/R) in vitro. The expression of HDAC3 and Rev-erbα in cardiomyocytes was increased under high-glucose conditions compared with low-glucose conditions, with decreased BMAL1 expression and mitophagy levels. After H/R stimulation, high glucose aggravated H/R injury, with upregulated HDAC3 and Rev-erbα expression and decreased BMAL1 and mitophagy levels. HDAC3 and Rev-erbα siRNA can alleviate high glucose-induced and H/R-induced injury by upregulating BMAL1 to increase mitophagy. Collectively, these findings suggest that disruption of HDAC3-mediated circadian gene expression oscillations induces mitophagy dysfunction, aggravating diabetic MI/RI. Cardiac-specific HDAC3 knockdown could alleviate diabetic MI/RI by regulating the Rev-erbα/BMAL1 pathway to restore the activation of mitophagy.

生物钟与糖尿病和心血管疾病的发生发展密切相关，生物钟紊乱会加剧心肌缺血/再灌注损伤（MI/RI）。HDAC3 是昼夜节律负反馈回路的关键组成部分，它控制昼夜节律核受体 Rev-erbα 的表达模式，以维持昼夜节律基因（如 BMAL1）的稳定性。然而，HDAC3 协调的 Rev-erbα/BMAL1 通路增加糖尿病 MI/RI 的机制及其与线粒体自噬的关系尚未阐明。在这里，我们观察到链脲佐菌素 (STZ) 诱导的糖尿病大鼠心脏中的时钟基因 Rev-erbα、BMAL1 和 C/EBPβ 振荡发生了改变，HDAC3 表达上调。根据受损和节律紊乱的昼夜节律依赖性线粒体自噬增加损伤，与非糖尿病 I/RI 心脏相比，糖尿病 MI/R 心脏中 Rev-erbα 和 BMAL1 的振荡迅速减弱。HDAC3 的基因敲低通过介导 Rev-erbα/BMAL1 昼夜节律途径来恢复线粒体自噬，从而显着减轻糖尿病 MI/RI。具有或不具有 HDAC3 siRNA 和 Rev-erbα siRNA 的原代心肌细胞在体外暴露于缺氧/复氧 (H/R)。与低糖条件相比，高糖条件下心肌细胞中 HDAC3 和 Rev-erbα 的表达增加，BMAL1 表达和线粒体自噬水平降低。H/R 刺激后，高糖加重 H/R 损伤，HDAC3 和 Rev-erbα 表达上调，BMAL1 和线粒体自噬水平降低。HDAC3 和 Rev-erbα siRNA 可以通过上调 BMAL1 增加线粒体自噬来减轻高糖诱导和 H/R 诱导的损伤。总的来说，这些发现表明 HDAC3 介导的昼夜节律基因表达振荡的破坏会诱导线粒体自噬功能障碍，加重糖尿病 MI/RI。心脏特异性 HDAC3 敲低可以通过调节 Rev-erbα/BMAL1 通路来恢复线粒体自噬的激活，从而减轻糖尿病 MI/RI。