WRW4

WRW4 shows potent activity in terms of inhibiting WKYMVm binding to FPRL1. WRW4 inhibits the activation of FPRL1 by WKYMVm, resulting in the complete inhibition of the intracellular calcium increase, extracellular signal-regulated kinase activation, and chemotactic migration of cells toward WKYMVm. WRW4 specifically inhibits the increase in intracellular calcium by the FPRL1 agonists MMK-1, amyloid β42 (Aβ42) peptide, and F peptide, but not by the FPR agonist, fMLF. Aβ42 peptide-induced superoxide generation and chemotactic migration of neutrophils are inhibited by WRW4, which also completely inhibits the internalization of Aβ42 peptide in human macrophages.^[1]

To determine whether WRW4 binds to FPRL1, FPRL1-expressing RBL-2H3 cells are labeled with 10 μM biotin-WRW4 for 30 min in PBS containing 0.02% sodium azide. The unbound biotin-WRW4 is washed extensively with PBS containing 0.2% BSA and 0.02% sodium azide. Then the cells are incubated with 5 μg/ml streptavidin-FITC at 4°C for 40 min in the dark. Subsequently, cells are washed twice in washing solution and fixed with 0.2% paraformaldehyde. Fixed cells are analyzed in single laser for FITC with FACSCalibur.

Male Swiss mice undergo intraplantar (i.pl.) injection with complete Freund’s adjuvant (CFA). WRW4 prevents the antihyperalgesic effect induced by either EA or BML-111. EA increases ANXA1 but does not alter FPR2/ALX receptor levels in the paw. Furthermore, i.pl. pretreatment with WRW4 prevents the increase of ANXA1 levels induced by EA.^[2]