Human ALX receptor regulates neutrophil recruitment in transgenic mice: roles in inflammation and host defense.
Signaling pathways instrumental in the temporal and spatial progression of acute inflammation toward resolution are of wide interest. Here a transgenic mouse with myeloid-selective expression of human lipoxin A4 receptor (hALX) was prepared and used to evaluate in vivo the effect of hALX expression. hALX-transfected HEK293 cells transmitted LXA4 signals that inhibit TNFalpha-induced NFkappaB activation. Transgenic FvB mice were generated by DNA injections of a 3.8 kb transgene consisting of the full-length hALX cDNA driven by a fragment of the hCD11b promoter. When topically challenged via dermal ear skin, hALX transgenic mice gave attenuated neutrophil infiltration (approximately 80% reduction) in response to leukotriene B4 (LTB4) plus prostaglandin E2 (PGE2) as well as approximately 50% reduction in PMN infiltrates (P<0.02) to receptor-bypass inflammation evoked by phorbol ester. The hALX transgenic mice gave markedly decreased PMN infiltrates to the peritoneum with zymosan and altered the dynamics of this response. Transgenic hALX mice displayed increased sensitivity with >50% reduction in PMN infiltrates to suboptimal doses (10 ng/mouse) of the ligand lipoxin A4 stable analog compared with <10% reduction of PMN in nontransgenic littermates. Soluble mediators generated within the local inflammatory milieu of hALX mice showed diminished ability to activate the proinflammatory transcription factor NFkappaB. Analyses of the lipid-derived mediators from exudates using LC-MS tandem mass spectroscopy indicated an altered profile in hALX transgenic mice that included lower levels of LTB4 and increased amounts of lipoxin A4 compared with nontransgenic littermates. Together these results demonstrate a gain-of-function with hALX transgenic mouse and indicate that ALX is a key receptor and sensor in formation of acute exudates and their resolution.
Devchand
Pallavi R
PR
Center for Experimental Therapeutics and Reperfusion Injury, Department of Anesthesiology, Perioperative and Pain Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115, USA.
Arita
Makoto
M
Hong
Song
S
Bannenberg
Gerard
G
Moussignac
Rose-Laure
RL
Gronert
Karsten
K
Serhan
Charles N
CN
D016475:3T3 Cells; D000818:Animals; D002460:Cell Line; D002853:Chromatography, Liquid / Q000379:methods; D015232:Dinoprostone / Q000494:pharmacology; D005260:Female; D006801:Humans; D006893:Hydroxyeicosatetraenoic Acids / Q000378:metabolism / Q000494:pharmacology; D007249:Inflammation / Q000276:immunology / Q000503:physiopathology; D007975:Leukotriene B4 / Q000378:metabolism / Q000494:pharmacology; D044045:Lipoxins; D008297:Male; D013058:Mass Spectrometry / Q000379:methods; D051379:Mice; D008822:Mice, Transgenic; D016328:NF-kappa B / Q000187:drug effects / Q000378:metabolism; D020556:Neutrophil Infiltration / Q000187:drug effects / Q000276:immunology*; D010537:Peritoneum / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D010538:Peritonitis / Q000139:chemically induced / Q000235:genetics / Q000628:therapy; D010957:Plasmids / Q000235:genetics; D011956:Receptors, Cell Surface / Q000235:genetics / Q000502:physiology*; D044042:Receptors, Formyl Peptide; D044067:Receptors, Lipoxin; D012867:Skin / Q000187:drug effects / Q000276:immunology / Q000473:pathology; D014162:Transfection; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology; D015054:Zymosan
C105101:FPR2 protein, human; D006893:Hydroxyeicosatetraenoic Acids; D044045:Lipoxins; D016328:NF-kappa B; D011956:Receptors, Cell Surface; D044042:Receptors, Formyl Peptide; D044067:Receptors, Lipoxin; D014409:Tumor Necrosis Factor-alpha; C040527:lipoxin A4; D007975:Leukotriene B4; D015054:Zymosan; D015232:Dinoprostone