title: Downregulation of angiotensin-converting enzyme by tumor necrosis factor-alpha and interleukin-1beta in cultured human endothelial cells.
abstract: Angiotensin-converting enzyme (ACE) and cytokines are considered to play an important role in the pathophysiology of cardiovascular diseases such as atherosclerosis. In the present study, the effects of the cytokines tumor necrosis factor-alpha (TNF-alpha) and interleukin-1beta (IL-1beta) on ACE in cultured human umbilical vein endothelial cells (HUVECs) was studied. TNF-alpha (0.1-10 ng/ml) and IL-1beta (0.1-10 ng/ml) caused a dose- and time-dependent decrease in the amount of ACE in intact endothelial cell membranes and decreased levels of ACE mRNA. TNF-alpha and IL-1beta activated p44/42 and p38 mitogen-activated protein kinases (MAPKs) in HUVECs; this was inhibited by the specific inhibitors of these kinases, PD98059 and SB202190, respectively. Pretreatment of endothelial cells with the specific p38 MAPK inhibitor SB202190 (5 microM) or hydrocortisone (5 microM) partly reversed the suppression of ACE by TNF-alpha or IL-1beta, whereas the specific p44/42 MAPK inhibitor PD98059 (40 microM) was without effect. Vascular endothelial growth factor (1 ng/ml) caused an increase in membrane-bound ACE and ACE mRNA levels which was inhibited by pretreatment of the cells with TNF-alpha (1 ng/ml) or IL-1beta (1 ng/ml). In summary, the cytokines TNF-alpha and IL-1beta downregulated ACE in cultured human endothelial cells, which effect was probably mediated by the p38 MAPK pathway. Downregulation of ACE by TNF-alpha and IL-1beta locally in the vascular wall may be a counterbalancing mechanism in inflammatory processes such as atherosclerosis, leading to decreased production of angiotensin II and accumulation of bradykinin.
authors.affiliation: Minerva Institute for Medical Research, Helsinki University Central Hospital, Helsinki, Finland. Outi.Saijonmaa@helsinki.fi
authors.forename: O
authors.initials: O
authors.lastname: Saijonmaa
authors.forename: T
authors.initials: T
authors.lastname: Nyman
authors.forename: F
authors.initials: F
authors.lastname: Fyhrquist
mesh_terms: D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D016228:Endothelial Growth Factors / Q000494:pharmacology; D004730:Endothelium, Vascular / Q000201:enzymology*; D004789:Enzyme Activation; D004791:Enzyme Inhibitors / Q000494:pharmacology; D015971:Gene Expression Regulation, Enzymologic; D006801:Humans; D006854:Hydrocortisone / Q000494:pharmacology; D007375:Interleukin-1 / Q000494:pharmacology*; D007700:Kinetics; D008222:Lymphokines / Q000494:pharmacology; D020928:Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors; D007703:Peptidyl-Dipeptidase A / Q000235:genetics* / Q000378:metabolism; D012333:RNA, Messenger / Q000032:analysis; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*; D014471:Umbilical Veins; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors; D048051:p38 Mitogen-Activated Protein Kinases
chemical_list: D016228:Endothelial Growth Factors; D004791:Enzyme Inhibitors; D007375:Interleukin-1; D008222:Lymphokines; D012333:RNA, Messenger; D014409:Tumor Necrosis Factor-alpha; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors; D020928:Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases; D007703:Peptidyl-Dipeptidase A; D006854:Hydrocortisone