RT Journal Article SR Electronic T1 Precisely control mitochondria with light to manipulate cell fate decision JF bioRxiv FD Cold Spring Harbor Laboratory SP 469668 DO 10.1101/469668 A1 Ernst, Patrick A1 Xu, Ningning A1 Qu, Jing A1 Chen, Herbert A1 Goldberg, Matthew S. A1 Darley-Usmar, Victor A1 Zhang, Jianyi J. A1 O’Rourke, Brian A1 Liu, Xiaoguang A1 Zhou, Lufang YR 2019 UL http://biorxiv.org/content/early/2019/05/29/469668.abstract AB Mitochondrial dysfunction has been implicated in many pathological conditions and diseases. The normal functioning of mitochondria relies on maintaining the inner mitochondrial membrane (IMM) potential (a.k.a. ΔΨm) that is essential for ATP synthesis, Ca2+ homeostasis, redox balance and regulation of other key signaling pathways such as mitophagy and apoptosis. However, the detailed mechanisms by which ΔΨm regulates cellular function remain incompletely understood, partially due to difficulty of manipulating ΔΨm with spatiotemporal resolution, reversibility, or cell type specificity. To address this need, we have developed a next-generation optogenetic-based technique for controllable mitochondrial depolarization with light. We demonstrate successful targeting of the heterologous Channelrhodopsin-2 (ChR2) fusion protein to the IMM and formation of functional cationic channels capable of light-induced selective ΔΨm depolarization and mitochondrial autophagy. Importantly, we for the first time show that optogenetic-mediated mitochondrial depolarization can be well-controlled to differentially influence the fate of cells expressing mitochondrial ChR2: while sustained moderate light illumination induces substantial apoptotic cell death, transient mild light illumination elicits cytoprotection via mitochondrial preconditioning. Finally, we show that Parkin overexpression exacerbates, instead of ameliorating, mitochondrial depolarization-mediated cell death in HeLa cells. In summary, we provide evidence that the described mitochondrial-targeted optogenetics may have a broad application for studying the role of mitochondria in regulating cell function and fate decision.