title: Oleic acid increases mitochondrial reactive oxygen species production and decreases endothelial nitric oxide synthase activity in cultured endothelial cells.
abstract: Elevated plasma levels of free fatty acids (FFA) are associated with increased cardiovascular risk. This may be related to FFA-induced elevation of oxidative stress in endothelial cells. We hypothesized that, in addition to mitochondrial production of reactive oxygen species, endothelial nitric oxide synthase (eNOS)-mediated reactive oxygen species production contributes to oleic acid (OA)-induced oxidative stress in endothelial cells, due to eNOS uncoupling. We measured reactive oxygen species production and eNOS activity in cultured endothelial cells (bEnd.3) in the presence of OA bound to bovine serum albumin, using the CM-H2DCFDA assay and the L-arginine/citrulline conversion assay, respectively. OA induced a concentration-dependent increase in reactive oxygen species production, which was inhibited by the mitochondrial complex II inhibitor thenoyltrifluoroacetone (TTFA). OA had little effect on eNOS activity when stimulated by a calcium-ionophore, but decreased both basal and insulin-induced eNOS activity, which was restored by TTFA. Pretreatment of bEnd.3 cells with tetrahydrobiopterin (BH4) prevented OA-induced reactive oxygen species production and restored inhibition of eNOS activity by OA. Elevation of OA levels leads to both impairment in receptor-mediated stimulation of eNOS and to production of mitochondrial-derived reactive oxygen species and hence endothelial dysfunction.
authors.affiliation: Department of Nephrology and Hypertension, University Medical Center Utrecht, Utrecht, The Netherlands.
authors.forename: Hendrik
authors.initials: H
authors.lastname: Gremmels
authors.affiliation: Department of Nephrology and Hypertension, University Medical Center Utrecht, Utrecht, The Netherlands.
authors.forename: Lonneke M
authors.initials: LM
authors.lastname: Bevers
authors.affiliation: Department of Nephrology and Hypertension, University Medical Center Utrecht, Utrecht, The Netherlands.
authors.forename: Joost O
authors.initials: JO
authors.lastname: Fledderus
authors.affiliation: Department of Medicine, Division of Nephrology and Immunology, University of Alberta Hospital, Edmonton, Canada; Department of Physiology, University of Alberta, Edmonton, Canada.
authors.forename: Branko
authors.initials: B
authors.lastname: Braam
authors.affiliation: Department of Nephrology and Hypertension, University Medical Center Utrecht, Utrecht, The Netherlands.
authors.forename: Anton Jan
authors.initials: AJ
authors.lastname: van Zonneveld
authors.affiliation: Department of Nephrology and Hypertension, University Medical Center Utrecht, Utrecht, The Netherlands.
authors.forename: Marianne C
authors.initials: MC
authors.lastname: Verhaar
authors.affiliation: Department of Nephrology and Hypertension, University Medical Center Utrecht, Utrecht, The Netherlands. Electronic address: J.A.Joles@umcutrecht.nl.
authors.forename: Jaap A
authors.initials: JA
authors.lastname: Joles
mesh_terms: D000818:Animals; D001692:Biological Transport; D001708:Biopterins / Q000031:analogs & derivatives / Q000494:pharmacology; D002417:Cattle; D002460:Cell Line; D042783:Endothelial Cells / Q000187:drug effects* / Q000378:metabolism*; D006801:Humans; D008928:Mitochondria / Q000187:drug effects* / Q000378:metabolism*; D009569:Nitric Oxide / Q000378:metabolism; D052250:Nitric Oxide Synthase Type III / Q000378:metabolism*; D019301:Oleic Acid / Q000378:metabolism / Q000494:pharmacology*; D017382:Reactive Oxygen Species / Q000378:metabolism*
chemical_list: D017382:Reactive Oxygen Species; D001708:Biopterins; D019301:Oleic Acid; D009569:Nitric Oxide; D052250:Nitric Oxide Synthase Type III; C003402:sapropterin
keywords: Endothelium; Fatty acids; Nitric oxide synthase; Oleic acid; Reactive oxygen species