Comparison of human eosinophil and neutrophil ligands for P-selectin: ligands for P-selectin differ from those for E-selectin.

Abstract

Eosinophils (EOS) and neutrophils (PMN) display different patterns of accumulation during various inflammatory reactions. We hypothesized that EOS and PMN may differ in their ligands for P-selectin, and that these ligands may differ from those previously identified for E-selectin. Recombinant human P-selectin was immobilized on plastic surfaces and adhesion of 51Cr-labeled human EOS or PMN was compared. EOS and PMN adhered in a concentration-dependent fashion, with similar maximal net adhesion. Preincubation with a blocking P-selectin antibody inhibited adhesion of both cell types, whereas a non-blocking antibody did not. To determine if the counterligands were sialylated proteins, cells were treated with various glycosidases and proteases before testing adhesion. Neuraminidase treatment markedly inhibited binding of both cell types, while endo-beta-galactosidase had no significant effect. Pretreatment with several proteases reduced adhesion of both cell types, although they consistently caused a greater inhibition of PMN binding than EOS binding. To determine whether the P-selectin ligands were surface structures whose expression or function may be altered by cell activation, leukocytes were pretreated with various stimuli; only platelet-activating factor (PAF) treatment reduced the capacity of leukocytes to adhere to P-selectin. Thus, the counterligands for P-selectin on EOS and PMN are similar sialylated, protease-sensitive, endo-beta-galactosidase-resistant structures, whose function and/or expression is reduced following treatment with PAF. These characteristics are clearly different than those reported for EOS and PMN ligands for E-selectin, and suggest disparate roles for P-selectin and E-selectin during EOS and PMN recruitment during inflammatory responses in vivo.

E-selectin receptors on human leukocytes

“…39 After 24 hours, the following glycosphingolipid biosynthesis inhibitors (or controls) were added: After an additional 24 hours, the cells were incubated with sodium [ 51 Cr]chromate (New Life Sciences Products, Boston, MA), and adhesion to purified recombinant E-selectin and P-selectin (R&D Systems) was determined as described previously. 16,17 Neutrophil purity and fresh cell viability were more than 97%. Post culture viability (Ͼ 60%) was equivalent for different treatments.…”

“…14 Treatment of mouse neutrophils with powerful proteases eliminated both P-selectin and E-selectin binding, whereas treatment of human neutrophils with the same proteases eliminated only P-selectin binding, leaving most Eselectin binding intact. [14][15][16][17] Gene-and RNA-targeted depletion identified glycoprotein receptors for E-selectin in mice. 18 However, if humans express different E-selectin receptors than mice, mouse genetics may not reveal their nature.…”

The Ser128Arg polymorphism of E-selectin gene is not associated with polycystic ovary syndrome

“…Although the P-selectin and E-selectin shares many properties, E-selectin is has been accepted to be a marker of endothelial dysfunction, whereas P-selectin usually reflects the procoagulant state [20]. The fact that there are different ligands for P-selectin and E-selectin suggest disparate roles for P-selectin and E-selectin during leukocyte recruitment in inflammatory responses [21]. More importantly, the association between circulating P-selectin and fibrinogen levels in cardiovascular disease (CVD) patients supports the thrombotic functions of P-selectin [22].…”

Eosinophil Tissue Recruitment to Sites of Allergic Inflammation in the Lung Is Platelet Endothelial Cell Adhesion Molecule Independent

“…Eosinophil adhesion and transmigration across endothelium is dependent upon several eosinophil-expressed adhesion receptors which mediate distinct steps in eosinophil adhesion to endothelium. For example, initial eosinophil rolling along endothelium is mediated by eosinophil cell surface receptors including L-selectin (2), P-selectin glycoprotein ligand 1 (3,4), ␣ 4 ␤ 1 integrins , and ␣ 4 ␤ 7 integrins (2, 5), whereas subsequent eosinophil-firm adhesion to endothelium is mediated by eosinophil ␤ 1 and ␤ 2 integrins (6 -9). On the endothelial cell surface P-selectin (3,4,6) and VCAM (5) mediate eosinophil rolling, while ICAM-1 (10) and VCAM-1 (5) mediate eosinophil-firm adhesion.…”

“…For example, initial eosinophil rolling along endothelium is mediated by eosinophil cell surface receptors including L-selectin (2), P-selectin glycoprotein ligand 1 (3,4), ␣ 4 ␤ 1 integrins , and ␣ 4 ␤ 7 integrins (2, 5), whereas subsequent eosinophil-firm adhesion to endothelium is mediated by eosinophil ␤ 1 and ␤ 2 integrins (6 -9). On the endothelial cell surface P-selectin (3,4,6) and VCAM (5) mediate eosinophil rolling, while ICAM-1 (10) and VCAM-1 (5) mediate eosinophil-firm adhesion. In contrast to the prominent recruitment of eosinophils to sites of allergic inflammation, neutrophils are recruited in particular to sites of bacterial infection, suggesting differential regulation of the recruitment of these two circulating leukocyte populations.…”