Poster U7 - Mitochondrial Optogenetic-mediated Preconditioning Protects Cells from Stress-induced Injury

Introduction: Emerging evidence suggests the involvement of mitochondria in preconditioning-mediated cytoprotection, yet the precise role of mitochondrial membrane potential (DYm) is not well defined. Our laboratory recently developed a novel mitochondrial-targeted optogenetic technology (mOpto) capable of inducing light intensity-dependent dynamic DYm depolarization across diverse cell types. This study aims to leverage mOpto to elucidate the contribution of DYm to mitochondrial-mediated preconditioning and its protective effects against stress-induced cell injury.

Materials and

Methods: Cardiomyocytes expressing mOpto gene were subjected to transient, low-intensity LED illumination to induce preconditioning, followed by exposure to various stressors such as FCCP, H2O2, or ischemia-reperfusion (I/R). Cell viability, DYm and reactive oxygen species (ROS) were measured. The underlying mechanistic pathways were explored by using bulk RNA-Seq. Moreover, whether the exosomes derived from preconditioning render cytoprotective effect was examined.

Results, Conclusions, and Discussions: Our findings demonstrate significantly higher cell viability in preconditioned cells post-stress compared to control groups, accompanied by reduced ROS levels and mitigated DYm depolarization. Notably, late-phase preconditioning exhibited superior cytoprotection relative to early-phase preconditioning. Mechanistic investigations revealed that mOpto-mediated cytoprotection does not rely on canonical reactive oxygen species or mitochondrial ATP-sensitive potassium channel opening but involves activation of anti-apoptotic and proliferation pathways. Intriguingly, exosomes derived from mOpto-preconditioned cells conferred similar cytoprotective effects, underscoring the potential for cell-free therapy. In conclusion, our data provide direct evidence that mOpto-mediated DYm preconditioning effectively protects cardiomyocytes from cell injury induced by various stressors.

Acknowledgements (Optional): This work was supported by NIH R01s HL156581 and HL160690, and AHA Predoctoral Fellowship 18PRE34060188 (to PE) and 906423 (SK).