The adhesiveness of monocytic U937 cells is stimulated by pro-inflammatory agents and inhibited by adenosine 3':5'-cyclic monophosphate.
We investigated the regulation of the adhesiveness of the human promonocytic cell line U-937, differentiated along the monocytic pathway either by 1,25-(OH)2-cholecalciferol or a combination of retinoic acid and dibutyryl cAMP. Adhesion to untreated polystyrene plastic was induced by inflammatory agents like PAF, fMLP or LTB4. The response to PAF first appeared after 48hr of differentiation and was inhibited by PAF antagonists and protein kinase C inhibitors indicating involvement of the phosphatidyl-inositol pathway in the stimulating effect. On the other hand, all the c-AMP raising agents tested inhibited PAF-induced cell adhesion, whatever their target membrane receptors, the Gs transducing protein, the catalytic unit of adenylate cyclase or cAMP phosphodiesterase. Direct stimulation of protein kinase A by Br8-cAMP had a similar effect. Moreover, PAF was able to increase cAMP levels. This suggests the existence of a cAMP based negative control mechanism limiting the action of PAF.
Ventura
M A
MA
U-282 INSERM, Hôpital Henri Mondor, Creteil, France.
Ribier
A
A
Delbourg
I
I
Chambaut-Guerin
A M
AM
Thomopoulos
P
P
D015762:2-Chloroadenosine / Q000494:pharmacology; D015124:8-Bromo Cyclic Adenosine Monophosphate / Q000494:pharmacology; D000241:Adenosine / Q000031:analogs & derivatives; D000527:Alprostadil / Q000494:pharmacology; D003994:Bucladesine / Q000494:pharmacology; D002117:Calcitriol / Q000494:pharmacology; D002448:Cell Adhesion / Q000187:drug effects*; D002454:Cell Differentiation / Q000187:drug effects; D002460:Cell Line; D000242:Cyclic AMP / Q000502:physiology*; D004075:Diglycerides / Q000494:pharmacology; D006801:Humans; D007700:Kinetics; D007975:Leukotriene B4 / Q000494:pharmacology*; D009000:Monocytes / Q000502:physiology*; D009240:N-Formylmethionine Leucyl-Phenylalanine / Q000494:pharmacology*; D010972:Platelet Activating Factor / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D014212:Tretinoin / Q000494:pharmacology
D004075:Diglycerides; D010972:Platelet Activating Factor; D015762:2-Chloroadenosine; D007975:Leukotriene B4; D015124:8-Bromo Cyclic Adenosine Monophosphate; D014212:Tretinoin; D009240:N-Formylmethionine Leucyl-Phenylalanine; D003994:Bucladesine; C038237:1-oleoyl-2-acetylglycerol; D000242:Cyclic AMP; D000527:Alprostadil; D002117:Calcitriol; D000241:Adenosine