Leukocytes, platelet-activating factor

Kunz D, Gerard NP, Gerard C. The human leukocyte platelet-activating factor recepbx, cDNA doning, cell surface expression, and construction of a novel epitope-bearing analog. J Biol Chem 1992 267 9101-9106... 

Takahashi, S., Yoshikawa, T., Naito, Y., Tanigawa, T., Yoshida, N., Kondo, M. (1991). Role of platelet-activating factor (PAF) in superoxide production by human polymorphonuclear leukocytes. Lipids 26,1227-30. 

In addition to their effects on leukocyte function, glucocorticoids influence the inflammatory response by reducing the prostaglandin, leukotriene, and platelet-activating factor synthesis that results from activation of phospholipase - Finally, glucocorticoids reduce expression... 

Chuang, T.T. Sallese, M. Ambrosini, G. Parruti, G. De Blasi, A. High expression of )8-adrenergic receptor kinase in human peripheral blood leukocytes. Isoproterenol and platelet activating factor can induce kinase translocation. J. Biol. Chem., 267, 6886-6892 (1992)... 

Nakamura M, Honda Z, Izumi T, Sakanaka C, Mutoh H, Minami M, Bito H, Seyama Y, Matsumoto T, Noma M, Shimizu T. Molecular cloning and expression of platelet-activating factor receptor from human leukocytes. J Biol Chem 1991 266 20400-20405... 

The intraperitoneal administration of berbamine into rats suppressed subcutaneous rat air pouch leukocyte infiltration that was induced by interleukin-1 (1L-1), tumor necrosis factor (TNF), and platelet-activating factor (PAF), at an EDJ0 20-30 mg/kg/3 days. The utilization of berbamine may be of value in the therapy of chronic inflammatory diseases where IL-1, TNF, and PAF play in role in pathogenesis [177]. 

Immunosuppressive agents, alone or in combination, are commonly used to alter the immune processes that are responsible for the glomerulonephritides. Corticosteroids, in addition to their immunosuppressive effecL also possess anti-inflammatory activities. They reduce the production and/or release of many substances that mediate the inflammatory process, such as prostaglandins, leukotrienes, platelet-activating factors, tumor necrosis factors (TNFs), and interleukin-1 (IL-1). Movement of leukocytes and macrophages to the site of inflammation is also inhibited. The immunosuppressive effects of corticosteroids are mediated through the inhibition of the release... 

A second delayed subacute phase is characterised by infiltration of leukocytes and phagocytic cells. The recruitment of inflammatory cells involves the concerted interaction of several types of chemotactic mediators such as complement factor C5a, platelet activating factor (PAF) and LTB4. Several cytokines, especially interleukin-1 (IL-1) and tumour... 

Platelet activating factor Prostaglandins Protein kinase C Phospholipase A2 Phospholipase C Polymorphonuclear leukocytes per os (Orally)... 

Figure 1. Interaction between leukocytes and endothelial cells of Mood vessels (modified from [3e]). Top overview bottom single steps with explanation of the symbols. Stimulation of endothelial cells by various mediators and factors leads to the expression of selectins and platelet-activating factor (PAF). The extravasation of leukocytes from the postcapillary venules starts with a weak, low-affinity, selectin-mediated adhesion of the leukocytes to endothelial cells, which leads to a slowing down of the leukocyte velocity (rolling). In the second phase a PAF-mediated activation of the leukocyte integrins occurs. In the third phase the activated integrins bind with high affinity to their ligands which are located on the endothelial cell surface. These ligands are called intercellular cell adhesion molecules (ICAM) and are members of the immunoglobulin superfamily. The firm adhesion of the leukocyte cells to the endothelium and finally their departure from the blood vessel (extravasation) results.

Anti-inflammatory effects Glucocorticoids have a dramatic effect on the distribution and function of leukocytes. These drugs increase neutrophils and decrease lymphocytes, eosinophils, basophils, and monocytes. The migration of leukocytes is also inhibited. The biochemical mechanisms underlying these cellular effects include the induced synthesis of an inhibitor of phospholipase A2 (see Chapter 18), decreased mRNA for COX-2, decreases in IL2 and IL3, ind decreases in platelet activating factor (PAF), an inflammatory cytokine. 

Omann G.M., Rengan, R., Hoffman, J.F. and Linderman, J.J. (1995). Rapid oscillations of actin polymerization/depolymerization in polymorphonuclear leukocytes stimulated by leukotriene R4 and platelet-activating factor. ]. Immunol. 155, 5375-5381. 

Rengan, R. and Omann, G.M. (1999). Regulation of oscillations in filamentous actin content in polymorphonuclear leukocytes stimulated with leukotriene B4 and platelet-activating factor. Biochem. Biophys. Res. Commun. 262, 479—486. 

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