title: Lack of activity of 15-epi-lipoxin A₄ on FPR2/ALX and CysLT1 receptors in interleukin-8-driven human neutrophil function.
abstract: Neutrophil recruitment and survival are important control points in the development and resolution of inflammatory processes. 15-epi-lipoxin (LX)A interaction with formyl peptide receptor 2 (FPR2)/ALX receptor is suggested to enhance anti-inflammatory neutrophil functions and mediate resolution of airway inflammation. However, it has been reported that 15-epi-LXA₄ analogues can also bind to cysteinyl leukotriene receptor 1 (CysLT1) and that the CysLT1 antagonist MK-571 binds to FPR2/ALX, so cross-reactivity between FPR2/ALX and CysLT1 ligands cannot be discarded. It is not well established whether the resolution properties reported for 15-epi-LXA4 are mediated through FPR2/ALX, or if other receptors such as CysLT1 may also be involved. Evaluation of specific FPR2/ALX ligands and CysLT1 antagonists in functional biochemical and cellular assays were performed to establish a role for both receptors in 15-epi-LXA₄-mediated signalling and function. In our study, a FPR2/ALX synthetic peptide (WKYMVm) and a small molecule FPR2/ALX agonist (compound 43) induced FPR2/ALX-mediated signalling, enhancing guanosine triphosphate-gamma (GTPγ) binding and decreasing cyclic adenosine monophosphate (cAMP) levels, whereas 15-epi-LXA₄ was inactive. Furthermore, 15-epi-LXA4 showed neither binding affinity nor signalling towards CysLT1. In neutrophils, 15-epi-LXA₄ showed a moderate reduction of interleukin (IL)-8-mediated neutrophil chemotaxis but no effect on neutrophil survival was observed. In addition, CysLT1 antagonists were inactive in FPR2/ALX signalling or neutrophil assays. In conclusion, 15-epi-LXA₄ is not a functional agonist or an antagonist of FPR2/ALX or CysLT1, shows no effect on IL-8-induced neutrophil survival and produces only moderate inhibition in IL-8-mediated neutrophil migration. Our data do not support an anti-inflammatory role of 15-epi-LXA₄- FPR2/ALX interaction in IL-8-induced neutrophil inflammation.
authors.affiliation: Respiratory Therapeutic Area-Discovery, Almirall, R&D Center, Sant Feliu de Llobregat, Barcelona, Spain. anna.planaguma@almirall.com
authors.forename: A
authors.initials: A
authors.lastname: Planagumà
authors.forename: T
authors.initials: T
authors.lastname: Domenech
authors.forename: I
authors.initials: I
authors.lastname: Jover
authors.forename: I
authors.initials: I
authors.lastname: Ramos
authors.forename: S
authors.initials: S
authors.lastname: Sentellas
authors.forename: R
authors.initials: R
authors.lastname: Malhotra
authors.forename: M
authors.initials: M
authors.lastname: Miralpeix
mesh_terms: D002465:Cell Movement / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D000242:Cyclic AMP / Q000378:metabolism; D006801:Humans; D016209:Interleukin-8 / Q000276:immunology; D044045:Lipoxins / Q000494:pharmacology*; D018375:Neutrophil Activation / Q000187:drug effects; D009504:Neutrophils / Q000187:drug effects* / Q000276:immunology; D011485:Protein Binding / Q000187:drug effects; D044042:Receptors, Formyl Peptide / Q000819:agonists*; D018077:Receptors, Leukotriene / Q000378:metabolism*; D044067:Receptors, Lipoxin / Q000819:agonists*; D015398:Signal Transduction / Q000187:drug effects
chemical_list: C105101:FPR2 protein, human; D016209:Interleukin-8; D044045:Lipoxins; D044042:Receptors, Formyl Peptide; D018077:Receptors, Leukotriene; D044067:Receptors, Lipoxin; C040527:lipoxin A4; D000242:Cyclic AMP; C083169:leukotriene D4 receptor
keywords: 15-epi-LXA4; FPR2/ALX; apoptosis; interleukin-8; neutrophils