title: Alterations in the activity and expression of endothelial NO synthase in aged human endothelial cells.
abstract: This study was to investigate factors underlying the age-related decrease in NO production in vascular endothelial cells. The age-related changes in NO production, the activity and expression level of eNOS, and eNOS binding proteins, were studied in HUVECs. NO production in HUVECs significantly decreased in an age-dependent manner. The potentiation of NO production by L-Arg was significantly suppressed by L-NIO (eNOS-specific inhibitor) in young HUVECs and was suppressed by 1400W (iNOS-specific inhibitor) in aged HUVECs. The aged HUVECs had lower eNOS protein levels than young cells. eNOS phosphorylation at Ser-1177 (active) decreased gradually from PDL 23 through 40, and eNOS phosphorylation at Thr-495 (inactive) increased in aged cells. Changes of intracellular eNOS binding proteins, such as caveolin-1, pAkt, and Hsp90, as well as interaction between eNOS and eNOS binding proteins, indicated decreasing enzyme activity in aged HUVECs. Aging might decrease the activity as well as expression level of eNOS in HUVECs. And the decrease in eNOS activity probably implicated to the alterations in the regulatory binding proteins. For further study, it needs to be confirmed that the age-related change in the intracellular distribution of eNOS and the relative contribution of eNOS and iNOS on vascular dysfunction in aged endothelial cells.
authors.affiliation: Department of Biochemistry, Medical School and the Research Institute of Medical Science, Chonnam National University, 5 Hak-Dong, Gwangju, 501-746, Republic of Korea.
authors.forename: Hyun Joong
authors.initials: HJ
authors.lastname: Yoon
authors.forename: Sang Wook
authors.initials: SW
authors.lastname: Cho
authors.forename: Bong Whan
authors.initials: BW
authors.lastname: Ahn
authors.forename: Sung Yeul
authors.initials: SY
authors.lastname: Yang
mesh_terms: D000375:Aging; D018929:Cell Culture Techniques; D002460:Cell Line; D002478:Cells, Cultured; D003470:Culture Media; D042783:Endothelial Cells / Q000378:metabolism*; D004730:Endothelium, Vascular / Q000201:enzymology* / Q000378:metabolism*; D015870:Gene Expression; D006801:Humans; D009569:Nitric Oxide / Q000378:metabolism; D052250:Nitric Oxide Synthase Type III / Q000235:genetics / Q000378:metabolism*; D014471:Umbilical Veins / Q000166:cytology
chemical_list: D003470:Culture Media; D009569:Nitric Oxide; C496314:NOS3 protein, human; D052250:Nitric Oxide Synthase Type III