Superoxide flashes: elemental events of mitochondrial ROS signaling in the heart.

Abstract

The role of mitochondrial reactive oxygen species (mitoROS) in cellular function remains obscure. By synthesizing recent data, we propose here that local dynamic mitoROS in the form of "superoxide flashes" serve as "signaling ROS" rather than "homeostatic ROS", distinguishable from basal mitoROS due to constitutive leakage of the electron transfer chain (ETC). Individual superoxide flashes are 10-s mitoROS bursts that are compartmentalized to a single mitochondrion or local mitochondrial networks. As a highly-conserved universal mitochondrial activity, it occurs in intact cells, in ex vivo beating hearts, and even in living animals. Unlike basal mitoROS, superoxide flashes are ignited by transient openings of a type of mitochondrial permeability transition pore (mPTP), and their incidence is richly regulated by an array of factors that converge on either the mPTP or ETC. Emerging evidence has shown that superoxide flashes decode dietary and metabolic status or exercise, gauge oxidative stress (e.g., during reoxygenation after hypoxia or anoxia), and constitute early mitochondrial signals that initiate oxidative stress-related apoptosis in a context-dependent manner. That they make only a miniscule contribution to global ROS attests to the high efficiency of local ROS signaling. However, the exact mechanisms underlying superoxide flash formation, regulation and function remain uncertain. Future investigation is warranted to uncover the cellular logic and molecular pathways of local dynamic mitoROS signaling in heart muscle cells and many other cell types.

• Authors: Xianhua Wang, Chongshu Jian, Xing Zhang, Zhanglong Huang, Jiejia Xu, Tingting Hou, Wei Shang, Yi Ding, Wanrui Zhang, Meng Ouyang, Yuefan Wang, Zhen Yang, Ming Zheng, Heping Cheng
• Journal: Journal of molecular and cellular cardiology (J Mol Cell Cardiol) Vol. 52 Issue 5 Pg. 940-8 (May 2012) ISSN: 1095-8584 [Electronic] England
• PMID: 22405973 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't, Review)
• Copyright: Copyright © 2012 Elsevier Ltd. All rights reserved.

Chemical References

• Mitochondrial Membrane Transport Proteins
• Mitochondrial Permeability Transition Pore
• Superoxides

Topics

• Animals
• Electron Transport
• Homeostasis
• Humans
• Mitochondria, Heart (metabolism)
• Mitochondrial Membrane Transport Proteins (metabolism, physiology)
• Mitochondrial Permeability Transition Pore
• Myocardium (cytology, metabolism)
• Oxidation-Reduction
• Signal Transduction
• Superoxides (metabolism)