Journal article
Modulation of peroxynitrite produced via mitochondrial nitric oxide synthesis during Ca2+ and succinate-induced oxidative stress in cardiac isolated mitochondria
Biochimica et biophysica acta. Bioenergetics, Vol.1861(12), pp.148290-148290
12/01/2020
DOI: 10.1016/j.bbabio.2020.148290
PMCID: PMC7560995
PMID: 32828729
Abstract
We hypothesized that NO• is generated in isolated cardiac mitochondria as the source for ONOO− production during oxidative stress. We monitored generation of ONOO− from guinea pig isolated cardiac mitochondria subjected to excess Ca2+ uptake before adding succinate and determined if ONOO− production was dependent on a nitric oxide synthase (NOS) located in cardiac mitochondria (mtNOS). Mitochondria were suspended in experimental buffer at pH 7.15, and treated with CaCl2 and then the complex II substrate Na-succinate, followed by menadione, a quinone redox cycler, to generate O2•−. L-tyrosine was added to the mitochondrial suspension where it is oxidized by ONOO− to form dityrosine (diTyr) in proportion to the ONOO− present. We found that exposing mitochondria to excess CaCl2 before succinate resulted in an increase in diTyr and amplex red fluorescence (H2O2) signals, indicating that mitochondrial oxidant stress, induced by elevated mtCa2+ and succinate, increased mitochondrial ONOO− production via NO• and O2•−. Changes in mitochondrial ONOO− production dependent on NOS were evidenced by using NOS inhibitors L-NAME/L-NNA, TEMPOL, a superoxide dismutase (SOD) mimetic, and PTIO, a potent global NO• scavenger. L-NAME and L-NNA decreased succinate and menadione-mediated ONOO− production, PTIO decreased production of ONOO−, and TEMPOL decreased ONOO− levels by converting more O2•− to H2O2. Electron microscopy showed immuno-gold labeled iNOS and nNOS in mitochondria isolated from cardiomyocytes and heart tissue. Western blots demonstrated iNOS and nNOS bands in total heart tissue, bands for both iNOS and nNOS in β-tubulin-free non-purified (crude) mitochondrial preparations, and a prominent iNOS band, but no nNOS band, in purified (Golgi and ER-free) mitochondria. Prior treatment of guinea pigs with lipopolysacharride (LPS) enhanced expression of iNOS in liver mitochondria but not in heart mitochondria. Our results indicate that release of ONOO− into the buffer is dependent both on O2•− released from mitochondria and NO• derived from a mtCa2+-inducible nNOS isoform, possibly attached to mitochondria, and a mtNOS isoform like iNOS that is non-inducible.
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•Cardiac isolated mitochondria produce and release ONOO−, a product of O2•− and NO•.•O2•− is generated by complex I during oxidative stress induced by excess CaCl2 and succinate.•NO• is generated within or near isolated mitochondria.•During oxidative stress mitochondrial ONOO− levels are modulated by O2•− and NO•.•Mitochondrial NOS is likely a variant of a non-inducible iNOS, but a nNOS may also contribute.
Details
- Title: Subtitle
- Modulation of peroxynitrite produced via mitochondrial nitric oxide synthesis during Ca2+ and succinate-induced oxidative stress in cardiac isolated mitochondria
- Creators
- Harrison J. Gerdes - Medical College of WisconsinMeiying Yang - Medical College of WisconsinJames S. Heisner - Medical College of WisconsinAmadou K.S. Camara - Medical College of WisconsinDavid F. Stowe - Medical College of Wisconsin
- Resource Type
- Journal article
- Publication Details
- Biochimica et biophysica acta. Bioenergetics, Vol.1861(12), pp.148290-148290
- Publisher
- Elsevier B.V
- DOI
- 10.1016/j.bbabio.2020.148290
- PMID
- 32828729
- PMCID
- PMC7560995
- ISSN
- 0005-2728
- eISSN
- 1879-2650
- Grant note
- DOI: 10.13039/100000738, name: U.S. Department of Veterans Affairs; DOI: 10.13039/100000002, name: National Institutes of Health
- Language
- English
- Date published
- 12/01/2020
- Academic Unit
- Anesthesia
- Record Identifier
- 9984296140802771
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