Department of Neurology, University of Pittsburgh, Pittsburgh, United States.
Pittsburgh Institute for Neurodegenerative Diseases, University of Pittsburgh, Pittsburgh, United States.
Elife. 2020 Mar 17;9:e51845. doi: 10.7554/eLife.51845.
Mitochondrial dysfunction is implicated in the pathogenesis of multiple neurological diseases, but elucidation of underlying mechanisms is limited experimentally by the inability to damage specific mitochondria in defined neuronal groups. We developed a precision chemoptogenetic approach to target neuronal mitochondria in the intact nervous system in vivo. MG2I, a chemical fluorogen, produces singlet oxygen when bound to the fluorogen-activating protein dL5** and exposed to far-red light. Transgenic zebrafish expressing dL5** within neuronal mitochondria showed dramatic MG2I- and light-dependent neurobehavioral deficits, caused by neuronal bioenergetic crisis and acute neuronal depolarization. These abnormalities resulted from loss of neuronal respiration, associated with mitochondrial fragmentation, swelling and elimination of cristae. Remaining cellular ultrastructure was preserved initially, but cellular pathology downstream of mitochondrial damage eventually culminated in neuronal death. Our work provides powerful new chemoptogenetic tools for investigating mitochondrial homeostasis and pathophysiology and shows a direct relationship between mitochondrial function, neuronal biogenetics and whole-animal behavior.
线粒体功能障碍与多种神经疾病的发病机制有关，但由于无法在特定神经元群体中损伤特定的线粒体，实验上对其潜在机制的阐明受到限制。我们开发了一种精确的化学遗传方法，可在体内完整的神经系统中靶向神经元线粒体。当与荧光素激活蛋白 dL5结合并暴露于远红光时，MG2I 是一种化学荧光团，会产生单线态氧。在神经元线粒体中表达 dL5的转基因斑马鱼表现出明显的 MG2I 和光依赖性神经行为缺陷，这是由神经元生物能危机和急性神经元去极化引起的。这些异常是由于神经元呼吸丧失引起的，与线粒体片段化、肿胀和嵴消除有关。最初保留了剩余的细胞超微结构，但线粒体损伤下游的细胞病理学最终导致神经元死亡。我们的工作为研究线粒体动态平衡和病理生理学提供了强大的新的化学遗传工具，并显示了线粒体功能、神经元生物遗传学和全动物行为之间的直接关系。
