National Institute for Biotechnology in the Negev, Ben Gurion University, Beer-Sheva 8410501, Israel.
Drug Discovery Unit, INCPM, Weizmann Institute of Science, Rehovot 76100, Israel.
Biochem J. 2020 Jan 31;477(2):461-475. doi: 10.1042/BCJ20190616.
Mitochondrial turnover is required for proper cellular function. Both mitochondrial biogenesis and mitophagy are impaired in several degenerative and age-related diseases. The search for mitophagy activators recently emerged as a new therapeutical approach; however, there is a lack in suitable tools to follow mitochondrial turnover in a high-throughput manner. We demonstrate that the fluorescent protein, MitoTimer, is a reliable and robust probe to follow mitochondrial turnover. The screening of 15 000 small molecules led us to two chemically-related benzothiophenes that stimulate basal mitophagy in the beta-cell line, INS1. Enhancing basal mitophagy was associated with improved mitochondrial function, higher Complex I activity and Complex II and III expressions in INS1 cells, as well as better insulin secretion performance in mouse islets. The possibility of further enhancing mitophagy in the absence of mitochondrial stressors points to the existence of a 'basal mitophagy spare capacity'. To this end, we found two small molecules that can be used as models to better understand the physiological regulation of mitophagy.
线粒体周转对于细胞的正常功能是必需的。在几种退行性和与年龄相关的疾病中，线粒体生物发生和自噬都受到损害。最近，寻找自噬激活剂成为一种新的治疗方法；然而，缺乏合适的工具来高通量地跟踪线粒体周转。我们证明荧光蛋白 MitoTimer 是一种可靠且强大的探针，可用于跟踪线粒体周转。对 15000 种小分子的筛选使我们发现了两种化学相关的苯并噻吩，它们可以刺激 INS1 胰岛β细胞系中的基础自噬。增强基础自噬与改善 INS1 细胞中的线粒体功能、提高复合物 I 活性以及复合物 II 和 III 的表达以及改善小鼠胰岛中的胰岛素分泌性能有关。在不存在线粒体应激的情况下进一步增强自噬的可能性表明存在“基础自噬备用容量”。为此，我们发现了两种小分子，可以用作模型来更好地理解自噬的生理调节。
