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Intracellular redox status and NAD(P)H:Quinone Oxidoreductase 1 (NQO1) activity in pulmonary arterial endothelial cells (PAEC)
Author(s) -
Bongard Robert,
Lindemer Brian,
Merker Marilyn
Publication year - 2008
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.22.1_supplement.1131.1
Subject(s) - nad+ kinase , chemistry , pentose phosphate pathway , intracellular , oxidative stress , biochemistry , glycerol 3 phosphate dehydrogenase , oxidoreductase , glutathione , redox , oxidative phosphorylation , enzyme , glycolysis , organic chemistry
NQO1 is a phase II antioxidant enzyme induced in PAEC by oxidative stress. Since isolated NQO1 utilizes either NADH or NADPH as electron donors, we asked whether either donor was preferentially utilized by NQO1 in intact calf PAEC. Intact PAEC NQO1 activity was measured using duroquinone (DQ) as the electron acceptor and cell pyridine nucleotide levels were measured by HPLC. Glycolysis was inhibited with 2‐deoxyglucose (2‐DG) or iodoacetate (IOA) and the pentose phosphate pathway by epiandrosterone (EPI). 2‐DG decreased NADH/NAD + and NADPH/NADP + ratios, by 70% and 52%, respectively, and intact cell DQ reduction capacity by 70%. For 2‐DG, lactate restored NADH/NAD + but not NADPH/NADP + or DQ reduction capacity. IOA decreased NADH/NAD + , had relatively little effect on NADPH/NADP + and did not decrease DQ reduction capacity. While EPI alone had no effect on redox status, DQ reduction decreased by 64%, and, when DQ was also present, NADPH/NADP + decreased by 87% with no decrease in NADH/NAD + . DQ alone also depressed NADPH/NADP + but not NADH/NAD + . Thus, intact PAEC DQ reduction capacity is more highly correlated with NADPH/NADP + than NADH/NAD + , implying NADPH as the preferred intracellular electron donor for NQO1. PAEC H 2 O 2 induced oxidative stress was also increased by EPI, suggesting that NADPH dependent NQO1 activity might be compromised under such conditions. Support: HL‐65537 and Dept. Veterans Affairs.