Potentiation of human polymorphonuclear leukocyte activation by atrial natriuretic peptide. Inhibitory effect of carnitine congeners.
Polymorphonuclear leukocytes (PMN), atrial natriuretic peptide (ANP) and leukotriene B4 (LTB4) reportedly play a major role in ischemia/reperfusion states of coronary artery disease. We sought to determine whether ANP and LTB4 cooperate in inducing PMN activation with consequent modulation of membrane molecules required for adherence to endothelium and myocardial cells, namely CD11b and L-selectin and the release of toxic oxygen radicals. ANP (from 10(-16) to 10(-8) M), LTB4 (from 10(-10) to 10(-6) M) and combinations of the two were incubated with normal PMN at 37 degrees C for 15 minutes. Membrane molecules modulation was measured by flow cytometry using specific monoclonal antibodies. Hydrogen peroxide production, an indicator of the capacity of PMN to release toxic oxygen species was quantified by flow cytometry using the peroxide-sensitive fluorescent probe dichlorofluorescein diacetate. ANP, uneffective when used alone, dose-dependently potentiated the PMN response to LTB4 (10(-9) M) as evidenced by an up-regulation of CD11b expression and peroxide production, and a down-regulation of L-selectin expression. These effects were prevented dose-dependently by the protein kinase C (PKC) inhibitor staurosporine (from 10 to 160 microM). Two carnitine congeners, palmytoylcarnitine (tested from 125 pg to 2 micrograms/ml) that also possesses an established ability to antagonise PKC and L-carnitine (tested from 12 to 200 ng/ml) were also effective. These data indicate that ANP potentiates LTB4 in inducing PMN mobilization and activation with a possible consequent detrimental effect on cardiac tissue and evisages the usefulness of PMN metabolism modulators.
Biselli
R
R
Rep. Medicinia, Lab. Immunologia, D.A.S.R.S., Aeroporto Pratica di Mare, Roma, Italy.
Farrace
S
S
De Simone
C
C
Fattorossi
A
A
D009320:Atrial Natriuretic Factor / Q000494:pharmacology*; D002331:Carnitine / Q000494:pharmacology*; D002448:Cell Adhesion / Q000187:drug effects; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism; D004357:Drug Synergism; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005786:Gene Expression Regulation / Q000187:drug effects; D006801:Humans; D006861:Hydrogen Peroxide / Q000378:metabolism; D019041:L-Selectin / Q000096:biosynthesis / Q000235:genetics; D007975:Leukotriene B4 / Q000494:pharmacology*; D016177:Macrophage-1 Antigen / Q000096:biosynthesis / Q000235:genetics; D015428:Myocardial Reperfusion Injury / Q000503:physiopathology / Q000517:prevention & control*; D009240:N-Formylmethionine Leucyl-Phenylalanine / Q000494:pharmacology; D009504:Neutrophils / Q000187:drug effects*; D010172:Palmitoylcarnitine / Q000494:pharmacology*; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism; D019311:Staurosporine / Q000494:pharmacology
D004791:Enzyme Inhibitors; D016177:Macrophage-1 Antigen; D017382:Reactive Oxygen Species; D019041:L-Selectin; D010172:Palmitoylcarnitine; D007975:Leukotriene B4; D009240:N-Formylmethionine Leucyl-Phenylalanine; D009320:Atrial Natriuretic Factor; D006861:Hydrogen Peroxide; D011493:Protein Kinase C; D019311:Staurosporine; D002331:Carnitine