title: The proteolytically stable peptidomimetic Pam-(Lys-βNSpe)6-NH2 selectively inhibits human neutrophil activation via formyl peptide receptor 2.
abstract: Immunomodulatory host defense peptides (HDPs) are considered to be lead compounds for novel anti-sepsis and anti-inflammatory agents. However, development of drugs based on HDPs has been hampered by problems with toxicity and low bioavailability due to in vivo proteolysis. Here, a subclass of proteolytically stable HDP mimics consisting of lipidated α-peptide/β-peptoid oligomers was investigated for their effect on neutrophil function. The most promising compound, Pam-(Lys-βNSpe)6-NH2, was shown to inhibit formyl peptide receptor 2 (FPR2) agonist-induced neutrophil granule mobilization and release of reactive oxygen species. The potency of Pam-(Lys-βNSpe)6-NH2 was comparable to that of PBP10, the most potent FPR2-selective inhibitor known. The immunomodulatory effects of structural analogs of Pam-(Lys-βNSpe)6-NH2 emphasized the importance of both the lipid and peptidomimetic parts. By using imaging flow cytometry in primary neutrophils and FPR-transfected cell lines, we found that a fluorescently labeled analog of Pam-(Lys-βNSpe)6-NH2 interacted selectively with FPR2. Furthermore, the interaction between Pam-(Lys-βNSpe)6-NH2 and FPR2 was found to prevent binding of the FPR2-specific activating peptide agonist Cy5-WKYMWM, while the binding of an FPR1-selective agonist was not inhibited. To our knowledge, Pam-(Lys-βNSpe)6-NH2 is the first HDP mimic found to inhibit activation of human neutrophils via direct interaction with FPR2. Hence, we consider Pam-(Lys-βNSpe)6-NH2 to be a convenient tool in the further dissection of the role of FPR2 in inflammation and homeostasis as well as for investigation of the importance of neutrophil stimulation in anti-infective therapy involving HDPs.
authors.affiliation: Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen, Denmark; Department of Rheumatology and Inflammation Research, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Guldhedsgatan 10A, 413 46 Gothenburg, Sweden. Electronic address: sals@sund.ku.dk.
authors.forename: Sarah Line
authors.initials: SL
authors.lastname: Skovbakke
authors.affiliation: Innate Immunology Group, National Veterinary Institute, Technical University of Denmark, Bülowsvej 27, DK-1870 Frederiksberg C, Denmark. Electronic address: PMHH@vet.dtu.dk.
authors.forename: Peter M H
authors.initials: PM
authors.lastname: Heegaard
authors.affiliation: Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen, Denmark. Electronic address: Camilla.josephine.larsen@gmail.com.
authors.forename: Camilla J
authors.initials: CJ
authors.lastname: Larsen
authors.affiliation: Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen, Denmark. Electronic address: henrik.franzyk@sund.ku.dk.
authors.forename: Henrik
authors.initials: H
authors.lastname: Franzyk
authors.affiliation: Department of Rheumatology and Inflammation Research, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Guldhedsgatan 10A, 413 46 Gothenburg, Sweden. Electronic address: Huamei.forsman@rheuma.gu.se.
authors.forename: Huamei
authors.initials: H
authors.lastname: Forsman
authors.affiliation: Department of Rheumatology and Inflammation Research, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Guldhedsgatan 10A, 413 46 Gothenburg, Sweden. Electronic address: claes.dahlgren@microbio.gu.se.
authors.forename: Claes
authors.initials: C
authors.lastname: Dahlgren
mesh_terms: D004305:Dose-Response Relationship, Drug; D018922:HL-60 Cells; D006801:Humans; D018375:Neutrophil Activation / Q000187:drug effects / Q000502:physiology*; D009504:Neutrophils / Q000187:drug effects / Q000378:metabolism*; D057786:Peptidomimetics / Q000494:pharmacology*; D059748:Proteolysis / Q000187:drug effects; D044042:Receptors, Formyl Peptide / Q000378:metabolism*; D044067:Receptors, Lipoxin / Q000378:metabolism*
chemical_list: C105101:FPR2 protein, human; D057786:Peptidomimetics; D044042:Receptors, Formyl Peptide; D044067:Receptors, Lipoxin
keywords: Anti-inflammatory; Formyl peptide receptors; G-protein-coupled receptors.; Host defense peptides; Neutrophils