Mitochondrial Ca2+ (mCa2+) uptake mediated by the mitochondrial calcium uniporter (MCU) plays a critical role in signal transduction, bioenergetics, and cell death, and its dysregulation is linked to several human diseases. In this study, we report a new ruthenium complex Ru265 that is cell-permeable, minimally toxic, and highly potent with respect to MCU inhibition. Cells treated with Ru265 show inhibited MCU activity without any effect on cytosolic Ca2+ dynamics and mitochondrial membrane potential (ΔΨm). Dose-dependent studies reveal that Ru265 is more potent than the currently employed MCU inhibitor Ru360. Site-directed mutagenesis of Cys97 in the N-terminal domain of human MCU ablates the inhibitory activity of Ru265, suggesting that this matrix-residing domain is its target site. Additionally, Ru265 prevented hypoxia/reoxygenation injury and subsequent mitochondrial dysfunction, demonstrating that this new inhibitor is a valuable tool for studying the functional role of the MCU in intact biological models.

中文翻译：

---

选择性和可透过细胞的线粒体钙Uniporter（MCU）抑制剂可在缺氧/复氧损伤后保留线粒体的生物能。

线粒体钙单向转运蛋白（MCU）介导的线粒体Ca2 +（mCa2 +）吸收在信号转导，生物能和细胞死亡中起关键作用，其失调与几种人类疾病有关。在这项研究中，我们报告了一种新的钌络合物Ru265，它具有细胞渗透性，最小的毒性，并且对MCU的抑制作用非常强。用Ru265处理的细胞显示出抑制的MCU活性，而对胞质Ca2 +动力学和线粒体膜电位（ΔΨm）没有任何影响。剂量依赖性研究表明，Ru265比目前使用的MCU抑制剂Ru360更有效。在人MCU的N端结构域中对Cys97进行定点诱变可消除Ru265的抑制活性，这表明该驻留于基质的结构域是其靶位点。此外，