Signal transduction during platelet-activating factor-induced lymphocyte binding to endothelial cells.
Platelet-activating factor (PAF) is a lipid mediator of inflammation. PAF pretreatment of cultured endothelial cells leads to an increase in lymphocyte binding. We have analysed the intracellular signal transduction during this PAF-induced effect. The protein kinase C activator, phorbol 12-myristate, 13-acetate, mimicked PAF in the binding assay. Concomitantly, the protein kinase C (PKC) inhibitor H7 down-regulated the PAF-induced binding to nearly control level. Also dibutyryl-cAMP treatment of endothelial cells increased lymphocyte binding, but the protein kinase A inhibitor HA1004 did not alter the PAF-induced binding. Furthermore, PAF did not increase the level of cytosolic cAMP in the endothelial cells. Other second messengers, cGMP and Ca2+, had no effect on lymphocyte binding. These findings suggest that protein kinase C, but not other signal transduction pathway, is essential in the PAF-induced lymphocyte binding to endothelial cells.
Renkonen
R
R
Department of Bacteriology and Immunology, University of Helsinki, Finland.
Mattila
P
P
Ustinov
J
J
D000818:Animals; D002448:Cell Adhesion; D000242:Cyclic AMP / Q000502:physiology; D004727:Endothelium / Q000502:physiology*; D007375:Interleukin-1 / Q000494:pharmacology; D008214:Lymphocytes / Q000502:physiology*; D010972:Platelet Activating Factor / Q000502:physiology*; D011493:Protein Kinase C / Q000502:physiology; D051381:Rats; D011919:Rats, Inbred Strains; D015398:Signal Transduction
D007375:Interleukin-1; D010972:Platelet Activating Factor; D000242:Cyclic AMP; D011493:Protein Kinase C