Identification of Peptides That Antagonize Formyl Peptide Receptor-Like 1-Mediated Signaling

Abstract

Formyl peptide receptor-like 1 (FPRL1) is an important classical chemoattractant receptor that is expressed in phagocytic cells in the peripheral blood and brain. Recently, various novel agonists have been identified from several origins, such as host-derived molecules. Activation of FPRL1 is closely related to inflammatory responses in the host defense mechanism and neurodegenerative disorders. In the present study we identified several novel peptides by screening hexapeptide libraries that inhibit the binding of one of FPRL1’s agonists (Trp-Lys-Tyr-Met-Val-d-Met-CONH2 (WKYMVm)) to its specific receptor, FPRL1, in RBL-2H3 cells. Among the novel peptides, Trp-Arg-Trp-Trp-Trp-Trp-CONH2 (WRWWWW (WRW4)) showed the most potent activity in terms of inhibiting WKYMVm binding to FPRL1. We also found that WRW4 inhibited 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. For the receptor specificity of WRW4 to the FPR family, we observed that WRW4 specifically inhibit 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. To investigate the effect of WRW4 on endogenous FPRL1 ligand-induced cellular responses, we examined its effect on Aβ42 peptide in human neutrophils. Aβ42 peptide-induced superoxide generation and chemotactic migration of neutrophils were inhibited by WRW4, which also completely inhibited the internalization of Aβ42 peptide in human macrophages. WRW4 is the first specific FPRL1 antagonist and is expected to be useful in the study of FPRL1 signaling and in the development of drugs against FPRL1-related diseases.

Lysophosphatidylglycerol inhibits formyl peptide receptor like-1-stimulated chemotactic migration and IL-1β production from human phagocytes

“…Until now, various kinds of agonists and a few antagonists have been reported for FPRL1 (Le et al, , 2002Bae et al, 2004). Besides from direct development of FPRL1 ligands, modulation of FPRL1 is possible via identifying a molecule that indirectly regulates FPRL1 activity after binding to other target molecules.…”

Pituitary Adenylate Cyclase-Activating Polypeptide 27 Is a Functional Ligand for Formyl Peptide Receptor-Like 1

“…However, some GPCR groups do codesensitize via single receptor activation for reasons, like receptor oligomerization, sequestration, and others (20). To solve this problem, we used the antagonizing peptide, WRW4, which does not activate but does bind FPRL1 (16). Desensitization events between two GPCRs usually occur via agonist-induced receptor activation (20).…”

“…Ligand-binding analysis was performed as previously described (16). Briefly, FPRL1/RBL cells were seeded at 1 ϫ 10 5 cells/well onto a 24-well plate and cultured overnight.…”

F2L, a peptide derived from heme‐binding protein, inhibits LL‐37‐induced cell proliferation and tube formation in human umbilical vein endothelial cells

“…FPRL1 Since F2L has been reported to induce the chemotactic migration of mouse neutrophils via FPR2 (mouse counterpart of human FPRL1) [15], we tested whether F2L stimulates the chemotactic migration of HUVECs via FPRL1, with the aid of an FPRL1-selective antagonist (WRW 4 ) [18]. The F2L-induced HUVEC chemotaxis was completely inhibited by WRW 4 (Fig.…”