title: Lyn- and ERK-mediated vs. Ca2+ -mediated neutrophil O responses with thermal injury.
abstract: We evaluated the dependency of neutrophil O production on PTK-Lyn and MAPK-ERK1/2 in rats after thermal injury. Activation of PTK-Lyn was assessed by immunoprecipitation. Phosphorylation of ERK1/2 was assessed by Western blot analysis. O production was measured by isoluminol-enhanced luminometry. Imaging technique was employed to measure neutrophil [Ca2+](i) in individual cells. Thermal injury caused marked upregulation of Lyn and ERK1/2 accompanying enhanced neutrophil O production. Treatment of rats with PTK blocker (AG556) or MAPK blocker (AG1478) before burn injury caused complete inhibition of the respective kinase activation. Both AG556 and AG1478 produced an ~66% inhibition in O production. Treatment with diltiazem (DZ) produced an ~37% inhibition of O production without affecting Lyn or ERK1/2 activation with burn injury. Ca2+ mobilization was upregulated with burn injury but not affected by treatment of burn rats with AG556. Unlike the partial inhibition of burn-induced O production by AG556, AG1478, or DZ, platelet-activating factor antagonist (PAFa) treatment of burn rats produced near complete inhibition of O production. PAFa treatment also blocked activation of Lyn. The findings suggest that the near complete inhibition of O production by PAFa was a result of blockade of PTK as well as Ca2+ signaling. Overall, our studies show that enhanced neutrophil O production after thermal injury is a result of potentiation of Ca2+ -linked and -independent signaling triggered by inflammatory agents such as PAF.
authors.affiliation: Burn & Shock Trauma Institute, Department of Surgery, Stritch School of Medicine, Loyola University Chicago, Maywood, Illinois 60153, USA.
authors.forename: Nadeem
authors.initials: N
authors.lastname: Fazal
authors.forename: Walid M
authors.initials: WM
authors.lastname: Al-Ghoul
authors.forename: Megan J
authors.initials: MJ
authors.lastname: Schmidt
authors.forename: Mashkoor A
authors.initials: MA
authors.lastname: Choudhry
authors.forename: Mohammed M
authors.initials: MM
authors.lastname: Sayeed
mesh_terms: D000818:Animals; D002056:Burns / Q000188:drug therapy / Q000276:immunology / Q000378:metabolism*; D002118:Calcium / Q000378:metabolism*; D002121:Calcium Channel Blockers / Q000494:pharmacology; D004789:Enzyme Activation / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology; D020935:MAP Kinase Signaling System / Q000502:physiology; D008297:Male; D019950:Mitogen-Activated Protein Kinase 1 / Q000037:antagonists & inhibitors / Q000378:metabolism*; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D009504:Neutrophils / Q000201:enzymology*; D010766:Phosphorylation; D010980:Platelet Membrane Glycoproteins / Q000037:antagonists & inhibitors / Q000378:metabolism; D011493:Protein Kinase C / Q000378:metabolism; D011799:Quinazolines; D051381:Rats; D017207:Rats, Sprague-Dawley; D017382:Reactive Oxygen Species / Q000378:metabolism; D011956:Receptors, Cell Surface / Q000037:antagonists & inhibitors / Q000378:metabolism; D043562:Receptors, G-Protein-Coupled; D020032:Tyrphostins / Q000494:pharmacology; D019061:src-Family Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism*
chemical_list: D002121:Calcium Channel Blockers; D004791:Enzyme Inhibitors; D010980:Platelet Membrane Glycoproteins; D011799:Quinazolines; D017382:Reactive Oxygen Species; D011956:Receptors, Cell Surface; D043562:Receptors, G-Protein-Coupled; D020032:Tyrphostins; C039351:platelet activating factor receptor; C098981:AG 556; C101044:RTKI cpd; C060902:lyn protein-tyrosine kinase; D019061:src-Family Kinases; D011493:Protein Kinase C; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases; D002118:Calcium