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Arch Biochem Biophys. 2017 Sep 15;630:1-8. doi: 10.1016/j.abb.2017.07.009. Epub 2017 Jul 20.

Association between ROS production, swelling and the respirasome integrity in cardiac mitochondria.

Author information

1
Department of Physiology, University of Puerto Rico School of Medicine, San Juan, Puerto Rico.
2
Department of Physiology, University of Puerto Rico School of Medicine, San Juan, Puerto Rico. Electronic address: sabzali.javadov@upr.edu.

Abstract

Although mitochondrial Ca2+ overload and ROS production play a critical role in mitochondria-mediated cell death, a cause-effect relationship between them remains elusive. This study elucidated the crosstalk between mitochondrial swelling, ROS production, and electron transfer chain (ETC) supercomplexes in rat heart mitochondria in response to Ca2+ and tert-butyl hydroperoxide (TBH), a lipid-soluble organic peroxide. Results showed that ROS production induced by TBH was significantly increased in the presence of Ca2+ in a dose-dependent manner. TBH markedly inhibited the state 3 respiration rate with no effect on the mitochondrial swelling. Ca2+ exerted a slight effect on mitochondrial respiration that was greatly aggravated by TBH. Analysis of supercomplexes revealed a minor difference in the presence of TBH and/or Ca2+. However, incubation of mitochondria in the presence of high Ca2+ (1 mM) or inhibitors of ETC complexes (rotenone and antimycin A) induced disintegration of the main supercomplex, respirasome. Thus, PTP-dependent swelling of mitochondria solely depends on Ca2+ but not ROS. TBH has no effect on the respirasome while Ca2+ induces disintegration of the supercomplex only at a high concentration. Intactness of individual ETC complexes I and III is important for maintenance of the structural integrity of the respirasome.

KEYWORDS:

Calcium; ETC respirasome; Heart mitochondria; Mitochondrial swelling; Reactive oxygen species

PMID:
28736227
PMCID:
PMC5568452
DOI:
10.1016/j.abb.2017.07.009
[Indexed for MEDLINE]
Free PMC Article

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