Contribution of mitochondrial network dynamics to intracellular ROS signaling

Abstract

Oxidative stresses can induce rapid depolarization of inner mitochondrial membrane potential and subsequent impairment of oxidative phosphorylation. Damaged mitochondria produce more reactive oxygen species (ROS), particularly the superoxide anion (O2-) and hydrogen peroxide (H2O2), which potentiate mitochondria-driven ROS propagation, so-called ROS-induced ROS release (RIRR), via activation of an inter-mitochondrial signaling network. In this context, mitochondrial network dynamics, such as their density, number, and spatial distribution, can affect mitochondria-driven ROS propagation. To investigate this inter-mitochondrial communication, we developed a mathematical model using an agent-based modeling approach, and tested the effect of mitochondrial network dynamics on RIRR for mitochondria under various conditions. Simulation results show that mitochondrial network dynamics are critical determinants of inter-mitochondrial ROS signaling patterns and main messenger ROS molecules. We further elucidated the potential mechanism of these actions, which is conversion of major messenger molecules involved in ROS signaling. Collectively, we propose that mitochondrial network dynamics can determine cellular responses to oxidative stress by switching the molecular species involved in cellular signaling.