title: Involvement of tyrosine protein kinase in IFN-gamma-induced human endothelial cell apoptosis.
abstract: Although it is well recognized that interferon-gamma (IFN-gamma) is involved in the development of systemic inflammatory response syndrome, a condition characterized by loss of endothelial barrier function, whether or not IFN-gamma has any direct effect on endothelial cell (EC) death is unclear. Furthermore, which signal transduction pathway involved in IFN-gamma-induced EC apoptosis remains to be elucidated. To answer these questions, we investigated the effect of IFN-gamma on EC death (apoptosis versus necrosis) and the underlying signal transduction pathway responsible for IFN-gamma-induced EC apoptosis. IFN-gamma resulted in a dose-dependent increase in EC apoptosis after 24 h incubation (p < .05). However, IFN-gamma did not induce EC necrosis. Tumor necrosis factor-alpha (TNF-alpha), but not lipopolysaccharide (LPS), had a augmentative effect on IFN-gamma-induced EC apoptosis (p < .05), while both of them alone failed to induce EC apoptosis. These results indicate that exposure of EC to IFN-gamma can cause apoptosis rather than necrosis. Both calcium ionophore, A23187, and the protein kinase C (PKC) activator phorbol-myristate-acetate (PMA) had a synergistic effect on IFN-gamma-induced EC apoptosis (p < .05). However, neither the calcium chelator 1,2-bis 2-aminophenoxy ethane-N,N,N',N'-tetraacetic acid (BAPTA), nor the PKC inhibitor 1 -5-isoquinolinysulfonyl 2-methyl piperazine (H-7) attenuated IFN-gamma-induced EC apoptosis. Three specific tyrosine protein kinase (TPK) inhibitors, herbimycin A, tyrphostin, and genistein, significantly inhibited IFN-gamma-induced EC apoptosis in a dose-dependent fashion (p < .05). Furthermore, the activation of TPK in EC by IFN-gamma was completely abrogated by these TPK inhibitors. These findings suggest that the signal transduction pathway required for induction of EC apoptosis by IFN-gamma is TPK dependent and is independent of calcium and PKC.
authors.affiliation: The Royal College of Surgeons in Ireland, Department of Surgery, Beaumont Hospital, Dublin.
authors.forename: J H
authors.initials: JH
authors.lastname: Wang
authors.forename: H P
authors.initials: HP
authors.lastname: Redmond
authors.forename: R W
authors.initials: RW
authors.lastname: Watson
authors.forename: C
authors.initials: C
authors.lastname: Condron
authors.forename: D
authors.initials: D
authors.lastname: Bouchier-Hayes
mesh_terms: D000328:Adult; D000368:Aged; D017209:Apoptosis / Q000187:drug effects*; D000001:Calcimycin / Q000494:pharmacology; D002118:Calcium / Q000502:physiology; D002478:Cells, Cultured; D004730:Endothelium, Vascular / Q000187:drug effects* / Q000201:enzymology / Q000473:pathology; D004789:Enzyme Activation; D006801:Humans; D007371:Interferon-gamma / Q000494:pharmacology*; D007476:Ionophores / Q000494:pharmacology; D008875:Middle Aged; D009336:Necrosis; D011493:Protein Kinase C / Q000378:metabolism; D011505:Protein-Tyrosine Kinases / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects
chemical_list: D007476:Ionophores; D000001:Calcimycin; D007371:Interferon-gamma; D011505:Protein-Tyrosine Kinases; D011493:Protein Kinase C; D002118:Calcium