Natural carboxyterminal truncation of human CXCL10 attenuates glycosaminoglycan binding, CXCR3A signaling and lymphocyte chemotaxis, while retaining angiostatic activity

• DOI: 10.1186/s12964-023-01453-1
• Publication Date: 2024-02-02T09:02:32Z
• Authors: Luna Dillemans; Karen Yu; Alexandra De Zutter; Sam Noppen; Mieke Gouwy; Nele Berghmans; Lisa Verhallen; Mirre De Bondt; Lotte Vanbrabant; Stef Brusselmans; Erik Martens; Dominique Schols; Patrick Verschueren; Mette M. Rosenkilde; Pedro Elias Marques; Sofie Struyf; Paul Proost
• Keywords: CXCR3

Abstract Background Interferon-γ-inducible protein of 10 kDa (IP-10/CXCL10) is a dual-function CXC chemokine that coordinates chemotaxis activated T cells and natural killer (NK) via interaction with its G protein-coupled receptor (GPCR), 3 (CXCR3). As consequence posttranslational modifications, human CXCL10 exhibits high degree structural functional heterogeneity. However, the biological effect processing at carboxy (C)-terminus has remained partially elusive. We studied (1–73) , lacking four endmost C-terminal amino acids, which was previously identified in supernatant cultured fibroblasts keratinocytes. Methods Relative levels intact (1–77) were determined synovial fluids patients rheumatoid arthritis (RA) through tandem mass spectrometry. The production optimized Fmoc-based solid phase peptide synthesis (SPPS) strategy to efficiently generate proteoforms introduced. compared using surface plasmon resonance for glycosaminoglycan (GAG) binding affinity, assays cell migration, second messenger signaling downstream CXCR3, flow cytometry CHO primary lymphocytes endothelial cells. Leukocyte recruitment vivo upon intraperitoneal injection also evaluated. Results Natural more abundantly present RA. had diminished affinity GAG including heparin, heparan sulfate chondroitin A. Moreover, exhibited an attenuated capacity induce CXCR3A-mediated signaling, as evidenced calcium mobilization quantification phosphorylated extracellular signal-regulated kinase-1/2 (ERK1/2) kinase B/Akt. Furthermore, incited significantly less lymphocyte vitro peritoneal ingress CXCR3 + mice. In contrast, loss residues did not affect inhibitory properties on proliferation, wound closure, phosphorylation ERK1/2, sprouting microvascular Conclusion Our study shows Lys 74 -Pro 77 are important binding, CXCR3A, chemotaxis, but dispensable angiostasis. Graphical