Mitochondria produce reactive nitrogen species via an arginine-independent pathway

Zsombor Lacza, Andrey V. Kozlov, Eszter Pankotai, Attila Csordás, Gerald Wolf, Heinz Redl, Márk Kollai, Csaba Szabó, David W. Busija, Thomas F.W. Horn

Research output: Contribution to journalArticlepeer-review

32 Scopus citations

Abstract

We measured the contribution of mitochondrial nitric oxide synthase (mtNOS) and respiratory chain enzymes to reactive nitrogen species (RNS) production. Diaminofluorescein (DAF) was applied for the assessment of RNS production in isolated mouse brain, heart and liver mitochondria and also in a cultured neuroblastoma cell line by confocal microscopy and flow cytometry. Mitochondria produced RNS, which was inhibited by catalysts of peroxynitrite decomposition but not by nitric oxide (NO) synthase inhibitors. Disrupting the organelles or withdrawing respiratory substrates markedly reduced RNS production. Inhibition of complex I abolished the DAF signal, which was restored by complex II substrates. Inhibition of the respiratory complexes downstream from the ubiquinone/ubiquinol cycle or dissipating the proton gradient had no effect on DAF fluorescence. We conclude that mitochondria from brain, heart and liver are capable of significant RNS production via the respiratory chain rather than through an arginine-dependent mtNOS.

Original languageEnglish (US)
Pages (from-to)369-378
Number of pages10
JournalFree Radical Research
Volume40
Issue number4
DOIs
StatePublished - Apr 2006
Externally publishedYes

Keywords

  • DAF-2
  • DAF-FM
  • NOS
  • Nitric oxide
  • Nitric oxide synthase
  • ONOO

ASJC Scopus subject areas

  • Biochemistry

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