Aspirin-triggered 15-epi-lipoxin A4 (LXA4) and LXA4 stable analogues are potent inhibitors of acute inflammation: evidence for anti-inflammatory receptors.
Lipoxins are bioactive eicosanoids that are immunomodulators. In human myeloid cells, lipoxin (LX) A4 actions are mediated by interaction with a G protein-coupled receptor. To explore functions of LXA4 and aspirin-triggered 5(S),6(R),15(R)-trihydroxy-7,9,13-trans-11-cis-eicosatetraenoic acid (15-epi-LXA4) in vivo, we cloned and characterized a mouse LXA4 receptor (LXA4R). When expressed in Chinese hamster ovary cells, the mouse LXA4R showed specific binding to [3H]LXA4 (K(d) approximately 1.5 nM), and with LXA4 activated GTP hydrolysis. Mouse LXA4R mRNA was most abundant in neutrophils. In addition to LXA4 and 15-epi-LXA4, bioactive LX stable analogues competed with both [3H]LXA4 and [3H]leukotriene D4 (LTD4)-specific binding in vitro to neutrophils and endothelial cells, respectively. Topical application of LXA4 analogues and novel aspirin-triggered 15-epi-LXA4 stable analogues to mouse ears markedly inhibited neutrophil infiltration in vivo as assessed by both light microscopy and reduced myeloperoxidase activity in skin biopsies. The 15(R)-16-phenoxy-17,18, 19,20-tetranor-LXA4 methyl ester (15-epi-16-phenoxy-LXA4), an analogue of aspirin triggered 15-epi-LXA4, and 15(S)-16-phenoxy-17,18,19,20-tetranor-LXA4 methyl ester (16-phenoxy-LXA4) were each as potent as equimolar applications of the anti-inflammatory, dexamethasone. Thus, we identified murine LXA4R, which is highly expressed on murine neutrophils, and showed that both LXA4 and 15-epi-LXA4 stable analogues inhibit neutrophil infiltration in the mouse ear model of inflammation. These findings provide direct in vivo evidence for an anti-inflammatory action for both aspirin-triggered LXA4 and LXA4 stable analogues and their site of action in vivo.
Takano
T
T
Center for Experimental Therapeutics and Reperfusion Injury, Department of Anesthesia, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115, USA.
Fiore
S
S
Maddox
J F
JF
Brady
H R
HR
Petasis
N A
NA
Serhan
C N
CN
D000595:Amino Acid Sequence; D000818:Animals; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000494:pharmacology*; D001241:Aspirin / Q000494:pharmacology*; D001483:Base Sequence; D016466:CHO Cells; D002634:Chemotaxis, Leukocyte; D003001:Cloning, Molecular; D006224:Cricetinae; D005260:Female; D006160:Guanosine Triphosphate / Q000378:metabolism; D006801:Humans; D006893:Hydroxyeicosatetraenoic Acids / Q000378:metabolism*; D007249:Inflammation / Q000517:prevention & control*; D044045:Lipoxins; D051379:Mice; D008807:Mice, Inbred BALB C; D008969:Molecular Sequence Data; D009504:Neutrophils / Q000276:immunology; D011956:Receptors, Cell Surface / Q000235:genetics; D044042:Receptors, Formyl Peptide; D044067:Receptors, Lipoxin; D011994:Recombinant Proteins / Q000378:metabolism; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D014018:Tissue Distribution
D000894:Anti-Inflammatory Agents, Non-Steroidal; C105101:FPR2 protein, human; D006893:Hydroxyeicosatetraenoic Acids; D044045:Lipoxins; D011956:Receptors, Cell Surface; D044042:Receptors, Formyl Peptide; D044067:Receptors, Lipoxin; D011994:Recombinant Proteins; C040527:lipoxin A4; D006160:Guanosine Triphosphate; D001241:Aspirin