Superoxide responses of endothelial cells to C5a and TNF-alpha: divergent signal transduction pathways.
There is increasing evidence that endothelial cells respond to a variety of mediators. In the current studies rat pulmonary artery endothelial cells (RPAEC) responded to human recombinant C5a and tumor necrosis factor-alpha (TNF-alpha) with the generation of superoxide (O2-). RPAEC responsiveness was dependent on whether cells had been obtained from confluent or subconfluent cell monolayers. RPAEC responded to C5a and TNF-alpha in a dose-dependent manner, with increases in intracellular Ca2+ (Cai2+), formation of D-myo-inositol 1,4,5-trisphosphate [Ins(1,4,5)P3], and generation of O2-. Optimal O2- responses occurred in cells that had been pretreated with the inhibitor of superoxide dismutase (SOD), diethyldithiocarbamate, and O2- responses were allopurinol insensitive. Pertussis toxin pretreatment abolished the ability of C5a to cause increases in Ins(1,4,5)P3 and Cai2+ and formation of O2- but did not inhibit the changes in Cai2+ and formation of O2- after addition of TNF-alpha. The O2- response to C5a but not to TNF-alpha was abolished by pretreatment with the inhibitor of protein kinase C, staurosporine. These data indicate that signal transduction events in response to C5a and TNF-alpha were fundamentally different.
Murphy
H S
HS
Department of Pathology, University of Michigan Medical School, Ann Arbor 48109-0602.
Shayman
J A
JA
Till
G O
GO
Mahrougui
M
M
Owens
C B
CB
Ryan
U S
US
Ward
P A
PA
D000470:Alkaloids / Q000494:pharmacology; D000493:Allopurinol / Q000494:pharmacology; D000818:Animals; D002118:Calcium / Q000378:metabolism; D015936:Complement C5a / Q000494:pharmacology*; D004050:Ditiocarb / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004730:Endothelium, Vascular / Q000166:cytology / Q000378:metabolism*; D015544:Inositol 1,4,5-Trisphosphate / Q000378:metabolism; D009994:Osmolar Concentration; D037342:Pertussis Toxin; D015398:Signal Transduction / Q000502:physiology*; D019311:Staurosporine; D013481:Superoxides / Q000378:metabolism*; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*; D010566:Virulence Factors, Bordetella / Q000494:pharmacology
D000470:Alkaloids; D014409:Tumor Necrosis Factor-alpha; D010566:Virulence Factors, Bordetella; D013481:Superoxides; D000493:Allopurinol; D015936:Complement C5a; D015544:Inositol 1,4,5-Trisphosphate; D004050:Ditiocarb; D037342:Pertussis Toxin; D019311:Staurosporine; D002118:Calcium