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Soluble Siglec-5 associates to PSGL-1 and displays anti-inflammatory activity.

ABSTRACT: Interactions between endothelial selectins and the leukocyte counter-receptor PSGL1 mediates leukocyte recruitment to inflammation sites. PSGL1 is highly sialylated, making it a potential ligand for Siglec-5, a leukocyte-receptor that recognizes sialic acid structures. Binding assays using soluble Siglec-5 variants (sSiglec-5/C4BP and sSiglec-5/Fc) revealed a dose- and calcium-dependent binding to PSGL1. Pre-treatment of PSGL1 with sialidase reduced Siglec-5 binding by 79?±?4%. In confocal immune-fluorescence assays, we observed that 50% of Peripheral Blood Mononuclear Cells (PBMCs) simultaneously express PSGL1 and Siglec-5. Duolink-proximity ligation analysis demonstrated that PSGL1 and Siglec-5 are in close proximity (<40?nm) in 31?±?4% of PBMCs. In vitro perfusion assays revealed that leukocyte-rolling over E- and P-selectin was inhibited by sSiglec-5/Fc or sSiglec-5/C4BP, while adhesion onto VCAM1 was unaffected. When applied to healthy mice (0.8?mg/kg), sSiglec-5/C4BP significantly reduced the number of rolling leukocytes under basal conditions (10.9?±?3.7 versus 23.5?±?9.3 leukocytes/field/min for sSiglec-5/C4BP-treated and control mice, respectively; p?=?0.0093). Moreover, leukocyte recruitment was inhibited over a 5-h observation period in an in vivo model of TNFalpha-induced inflammation following injection sSiglec-5/C4BP (0.8?mg/kg). Our data identify PSGL1 as a ligand for Siglec-5, and soluble Siglec-5 variants appear efficient in blocking PSGL1-mediated leukocyte rolling and the inflammatory response in general.

SUBMITTER: Pepin M

PROVIDER: S-EPMC5125011 | biostudies-literature | 2016 Nov

REPOSITORIES: biostudies-literature

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Soluble Siglec-5 associates to PSGL-1 and displays anti-inflammatory activity.

Pepin Marion M Mezouar Soraya S Pegon Julie J Muczynski Vincent V Adam Frédéric F Bianchini Elsa P EP Bazaa Amine A Proulle Valerie V Rupin Alain A Paysant Jerome J Panicot-Dubois Laurence L Christophe Olivier D OD Dubois Christophe C Lenting Peter J PJ Denis Cécile V CV

Scientific reports 20161128

Interactions between endothelial selectins and the leukocyte counter-receptor PSGL1 mediates leukocyte recruitment to inflammation sites. PSGL1 is highly sialylated, making it a potential ligand for Siglec-5, a leukocyte-receptor that recognizes sialic acid structures. Binding assays using soluble Siglec-5 variants (sSiglec-5/C4BP and sSiglec-5/Fc) revealed a dose- and calcium-dependent binding to PSGL1. Pre-treatment of PSGL1 with sialidase reduced Siglec-5 binding by 79 ± 4%. In confocal immun ...[more]

PMID: 27892504

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Soluble Siglec-5 associates to PSGL-1 and displays anti-inflammatory activity.

Publications

Soluble Siglec-5 associates to PSGL-1 and displays anti-inflammatory activity.

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