Whereas elimination of damaged mitochondria by mitophagy is proposed to be cardioprotective, the regulation of mitophagy at reperfusion and the underlying mechanism remain elusive. Since mitochondrial Zn²⁺ may control mitophagy by regulating mitochondrial membrane potential (MMP), we hypothesized that the zinc transporter ZIP7 that controls Zn²⁺ levels within mitochondria would contribute to reperfusion injury by regulating mitophagy. Mouse hearts were subjected to ischemia/reperfusion in vivo. Mitophagy was evaluated by detecting mitoLC3II, mito-Keima, and mitoQC. ROS were measured with DHE and mitoB. Infarct size was measured with TTC staining. The cardiac-specific ZIP7 conditional knockout mice (ZIP7 cKO) were generated by adopting the CRISPR/Cas9 system. Human heart samples were obtained from donors and recipients of heart transplant surgeries. KO or cKO of ZIP7 increased mitophagy under physiological conditions. Mitophagy was not activated at the early stage of reperfusion in mouse hearts. ZIP7 is upregulated at reperfusion and ZIP7 cKO enhanced mitophagy upon reperfusion. cKO of ZIP7 led to mitochondrial depolarization by increasing mitochondrial Zn²⁺ and, accumulation of PINK1 and Parkin in mitochondria, suggesting that the decrease in mitochondrial Zn²⁺ in response to ZIP7 upregulation resulting in mitochondrial hyperpolarization may impede PINK1 and Parkin accumulation in mitochondria. Notably, ZIP7 is markedly upregulated in cardiac mitochondria from patients with heart failure (HF), whereas mitochondrial PINK1 accumulation and mitophagy were suppressed. Furthermore, ZIP7 cKO reduced mitochondrial ROS generation and myocardial infarction via a PINK1-dependet manner, whereas overexpression of ZIP7 exacerbated myocardial infarction. Our findings identify upregulation of ZIP7 leading to suppression of mitophagy as a critical feature of myocardial reperfusion injury. A timely suppression of cardiac ZIP7 upregulation or inactivation of ZIP7 is essential for the treatment of reperfusion injury.

虽然通过线粒体自噬消除受损线粒体被认为具有心脏保护作用，但再灌注时线粒体自噬的调节及其潜在机制仍然难以捉摸。由于线粒体 Zn ²⁺可能通过调节线粒体膜电位 (MMP) 来控制线粒体自噬，我们假设控制 Zn ^{2+的锌转运蛋白 ZIP7}线粒体内的水平将通过调节线粒体自噬而导致再灌注损伤。小鼠心脏在体内进行缺血/再灌注。通过检测 mitoLC3II、mito-Keima 和 mitoQC 来评估线粒体自噬。用 DHE 和 mitoB 测量 ROS。用TTC染色测量梗死面积。采用 CRISPR/Cas9 系统生成心脏特异性 ZIP7 条件性敲除小鼠 (ZIP7 cKO)。人类心脏样本是从心脏移植手术的捐赠者和接受者那里获得的。ZIP7 的 KO 或 cKO 在生理条件下增加了线粒体自噬。在小鼠心脏再灌注的早期阶段，线粒体自噬没有被激活。ZIP7 在再灌注时上调，ZIP7 cKO 在再灌注时增强线粒体自噬。^{ZIP7 的 cKO 通过增加线粒体 Zn 2+}导致线粒体去极化并且，线粒体中 PINK1 和 Parkin 的积累，表明线粒体 Zn ^2+的减少响应 ZIP7 上调导致线粒体超极化可能会阻碍 PINK1 和 Parkin 在线粒体中的积累。值得注意的是，ZIP7 在心力衰竭 (HF) 患者的心脏线粒体中显着上调，而线粒体 PINK1 的积累和线粒体自噬受到抑制。此外，ZIP7 cKO 通过 PINK1 依赖性方式减少线粒体 ROS 的产生和心肌梗死，而 ZIP7 的过表达加剧了心肌梗死。我们的研究结果确定了导致抑制线粒体自噬的 ZIP7 上调是心肌再灌注损伤的一个关键特征。及时抑制心脏 ZIP7 上调或 ZIP7 失活对于治疗再灌注损伤至关重要。