Photostimulation activates restorable fragmentation of single mitochondrion by initiating oxide flashes

TL;DR

This study introduces a precise photostimulation technique using femtosecond laser to induce and study reversible mitochondrial fragmentation, highlighting the role of reactive oxygen species and membrane potential oscillations.

Contribution

It presents a novel, controllable method for activating mitochondrial fragmentation at the single-organelle level with high spatial and temporal resolution.

Findings

Reactive oxygen species flashes are critical for mitochondrial fragmentation.

Mitochondria recover their structure within tens of seconds after fragmentation.

Photostimulation provides a controllable tool for mitochondrial dynamics research.

Abstract

Mitochondrial research is important to ageing, apoptosis, and mitochondrial diseases. In previous works, mitochondria are usually stimulated indirectly by proapoptotic drugs to study mitochondrial development, which is in lack of controllability, or spatial and temporal resolution. These chemicals or even gene techniques regulating mitochondrial dynamics may also activate other inter- or intra-cellular processes simultaneously. Here we demonstrate a photostimulation method on single-mitochondrion level by tightly-focused femtosecond laser that can precisely activate restorable fragmentation of mitochondria which soon recover their original tubular structure after tens of seconds. In this process, series of mitochondrial reactive oxygen species (mROS) flashes are observed and found very critical to mitochondrial fragmentation. Meanwhile, transient openings of mitochondrial permeability transition pores (mPTP), suggested by oscillations of mitochondrial membrane potential, contribute to the scavenging of redundant mROS and recovery of fragmented mitochondria. Those results demonstrate photostimulation as an active, precise and controllable method for the study of mitochondrial oxidative and morphological dynamics or related fields.