Cytosolic NADPH may regulate differences in basal Nox oxidase-derived superoxide generation in bovine coronary and pulmonary arteries

Sachin A. Gupte, Pawel M. Kaminski, Beverly Floyd, Ritu Agarwal, Noorjahan Ali, Mansoor Ahmad, John Edwards, Michael S. Wolin

Research output: Contribution to journalArticle

106 Scopus citations

Abstract

Because systems controlled by basal NAD(P)H oxidase activity appear to contribute to differences in responses of endothelium-removed bovine coronary (BCA) and pulmonary (BPA) arteries to hypoxia, we characterized the Nox oxidases activities present in these vascular segments and how cytosolic NAD(P)H redox systems could be controlling oxidase activity. BPA generated ∼60-80% more lucigenin (5 μM) chemiluminescence detectable superoxide than BCA. Apocynin (10 μM), a NAD(P)H oxidase inhibitor, and 6-aminonicotinamide (1 mM), a pentose phosphate inhibitor (PPP), both attenuated (approximately by 50-70%) superoxide detected in BPA and BCA. There was no significant difference in the expression of Nox2 or Nox4 mRNA or protein detected by Western blot analysis. NADPH and NADH increased superoxide in homogenates and isolated microsomal membrane fractions in a manner consistent with BPA and BCA having similar levels of oxidase activity. BPA had 4.2-fold higher levels of NADPH than BCA. The activity and protein levels of glucose-6-phosphate dehydrogenase (G6PD), the rate-limiting PPP enzyme generating cytosolic NADPH, were 1.5-fold higher in BPA than BCA. Thus BPA differ from BCA in that they have higher levels of G6PD activity, NADPH, and superoxide. Because both arteries have similar levels of Nox expression and activity, elevated levels of cytosolic NADPH may contribute to increased superoxide in BPA.

Original languageEnglish (US)
Pages (from-to)H13-H21
JournalAmerican Journal of Physiology - Heart and Circulatory Physiology
Volume288
Issue number1 57-1
DOIs
StatePublished - Jan 2005

Keywords

  • Glucose-6-phosphate dehydrogenase
  • Lactate
  • NAD(P)H oxidase
  • Nox2
  • Nox4
  • Pentose phosphate pathway

ASJC Scopus subject areas

  • Physiology
  • Cardiology and Cardiovascular Medicine
  • Physiology (medical)

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