A role for PKC-delta and PI 3-kinase in TNF-alpha-mediated antiapoptotic signaling in the human neutrophil.
The proinflammatory cytokine tumor necrosis factor (TNF)-alpha has been implicated in the attenuation of neutrophil spontaneous apoptosis during sepsis. Antiapoptotic signaling is principally mediated through the p60TNF receptor (p60TNFR). In neutrophils, TNF-alpha is an incomplete secretagogue and requires input from a ligated integrin(s) for neutrophil activation. In adherent neutrophils, TNF-alpha triggers association of both protein kinase C (PKC)-delta and phosphatidylinositol (PI) 3-kinase with the p60TNFR. In this study, a role for PKC-delta and PI 3-kinase in TNF-alpha-mediated antiapoptotic signaling was examined. TNF-alpha inhibited spontaneous apoptosis in fibronectin-adherent neutrophils, and this antiapoptotic signaling was blocked by the PKC-delta inhibitor rottlerin, but not by an inhibitor of Ca(2+)-dependent PKC isotypes, Go-6976. Inhibition of PI 3-kinase by LY-294002 also inhibited TNF-alpha-mediated antiapoptotic signaling. Cycloheximide blocked TNF-alpha-mediated antiapoptotic signaling, suggesting protein synthesis is required. Inhibition of either PKC-delta or PI 3-kinase attenuated TNF-alpha-mediated activation of the antiapoptotic transcription factor NFkappaB. Thus both PKC-delta and PI 3-kinase have essential roles in TNF-alpha-mediated antiapoptotic signaling in adherent neutrophils.
Kilpatrick
Laurie E
LE
Department of Pediatrics, University of Pennsylvania School of Medicine and the Joseph Stokes Jr. Research Institute, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania 19104, USA. kilpatrick@emailchop.edu
Lee
Julia Y
JY
Haines
Kathleen M
KM
Campbell
Donald E
DE
Sullivan
Kathleen E
KE
Korchak
Helen M
HM
D000098:Acetophenones / Q000008:administration & dosage / Q000494:pharmacology; D000328:Adult; D017209:Apoptosis / Q000502:physiology*; D001578:Benzopyrans / Q000008:administration & dosage / Q000494:pharmacology; D053148:Caspase 3; D061945:Caspase Inhibitors; D020169:Caspases / Q000378:metabolism; D002478:Cells, Cultured; D002867:Chromones / Q000008:administration & dosage / Q000494:pharmacology; D003513:Cycloheximide / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004791:Enzyme Inhibitors / Q000008:administration & dosage / Q000494:pharmacology; D006801:Humans; D007527:Isoenzymes / Q000037:antagonists & inhibitors / Q000502:physiology*; D009025:Morpholines / Q000008:administration & dosage / Q000494:pharmacology; D016328:NF-kappa B / Q000502:physiology; D009504:Neutrophils / Q000502:physiology*; D019869:Phosphatidylinositol 3-Kinases / Q000502:physiology*; D000081082:Phosphoinositide-3 Kinase Inhibitors; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000502:physiology*; D051745:Protein Kinase C-delta; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology; D015398:Signal Transduction / Q000502:physiology*; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology / Q000502:physiology*
D000098:Acetophenones; D001578:Benzopyrans; D053148:Caspase 3; D061945:Caspase Inhibitors; D020169:Caspases; D002867:Chromones; D003513:Cycloheximide; D004791:Enzyme Inhibitors; D007527:Isoenzymes; D009025:Morpholines; D016328:NF-kappa B; D019869:Phosphatidylinositol 3-Kinases; D000081082:Phosphoinositide-3 Kinase Inhibitors; D011493:Protein Kinase C; D051745:Protein Kinase C-delta; D011500:Protein Synthesis Inhibitors; D014409:Tumor Necrosis Factor-alpha; C085911:2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one; C085746:rottlerin; C497258:PRKCD protein, human; C505407:CASP3 protein, human