biological activity of cxcl8 forms generated by alternative cleavage of the signal peptide or by aminopeptidase-mediated truncation生物活性替代乳沟cxcl8形式生成的信号肽或aminopeptidase-mediated截断.pdf

Biological Activity of CXCL8 Forms Generated by Alternative Cleavage of the Signal Peptide or by Aminopeptidase-Mediated Truncation Anneleen Mortier, Nele Berghmans, Isabelle Ronsse, Karolien Grauwen, Steve Stegen, Jo Van Damme, Paul Proost* The Laboratory of Molecular Immunology, Department of Microbiology Immunology, Rega Institute, Katholieke Universiteit Leuven (K. U. Leuven), Leuven, Belgium Abstract Background: Posttranslational modification of chemokines is one of the mechanisms that regulate leukocyte migration during inflammation. Multiple natural NH2-terminally truncated forms of the major human neutrophil attractant interleukin- 8 or CXCL8 have been identified. Although differential activity was reported for some CXCL8 forms, no biological data are available for others. Methodology/Principal Findings: Aminopeptidase-cleaved CXCL8(2-77) and CXCL8(3-77), the product of alternative cleavage of the signal peptide CXCL8(-2-77) and the previously studied forms containing 77 and 72 amino acids, CXCL8(1- 77) and CXCL8(6-77), were prepared by solid-phase peptide synthesis, purified and folded into active proteins. No differences in binding and calcium signaling potency were detected between CXCL8(1-77), CXCL8(-2-77), CXCL8(2-77) and CXCL8(3-77) on cells transfected with one of the human CXCL8 receptors, i.e. CXCR1 and CXCR2. However, CXCL8(-2-77) was more potent compared to CXCL8(1-77), CXCL8(2-77) and CXCL8(3-77) in signaling and in vitro chemotaxis of peripheral blood-derived human neutrophils. Moreover, CXCL8(-2-77) was less efficiently processed by plasmin into the more potent CXCL8(6-77). The truncated forms CXCL8(2-77) and CXCL8(3-77) had higher affinity for heparin than CXCL8(1-77), a property important for the presentation of CXCL8 on endothelial layers. Upon intraperi