Lipoxin A4 Regulates Natural Killer Cell in Asthma
Reporter: Larry H Bernstein, MD, FCAP
- endogenous counterregulatory signaling pathways are dysregulated.
- natural killer (NK) cells and
- type 2 ILCs (ILC2s),
- can participate in the regulation of allergic airway responses,
- in particular airway mucosal inflammation.
- the pro-resolving ALX/FPR2 receptors.
- increased NK cell–mediated eosinophil apoptosis and
- decreased IL-13 release by ILC2s.
- to decrease airway inflammation and mediate the catabasis of eosinophilic inflammation
Molecular biology for formyl peptide receptors in human diseases
Yongsheng Li ,
- Duyun Ye
http://dx.doi.org/10.1007/s00109-013-1005-5 Online ISSN1432-1440 Print ISSN0946-2716
Journal of Molecular Medicine February 2013 http://link.springer.com/article/10.1007/s00109-013-1005-5
Leukocytes accumulate at sites of inflammation and immunological reaction in response to locally existing chemotactic mediators. The first chemotactic factors structurally defined were N-formyl peptides. Subsequently, numerous ligands were identified
- to activate formyl peptide receptors (FPRs) that belong to the
- seven-transmembrane G protein-coupled receptor superfamily.
FPRs interact with this menagerie of structurally diverse pro- and anti-inflammatory ligands to possess important regulatory effects in multiple diseases, including
- inflammation,
- amyloidosis,
- Alzheimer’s disease,
- prion disease,
- acquired immunodeficiency syndrome,
- obesity,
- diabetes, and
- cancer.
How these receptors recognize diverse ligands and how they contribute to disease pathogenesis and host defense are basic questions currently under investigation that
- would open up new avenues for the future management of inflammation-related diseases.
FPR2/ALX receptor expression and internalization are critical for lipoxin A4 and annexin-derived peptide-stimulated phagocytosis
PMaderna, DC Cottell, T Toivonen, N Dufton, J Dalli, M Perretti and C Godson
The FASEB Journal Nov 2010; 24 (11): 4240-4249 Published online June 22, 2010, http://dx.doi.org/10.1096/fj.10-159913
Lipoxins (LXs) are endogenously produced eicosanoids with well-described anti-inflammatory and proresolution activities,
- stimulating nonphlogistic phagocytosis of apoptotic cells by macrophages.
LXA4 and the glucocorticoid-derived annexin A1 peptide (Ac2–26) bind to a common G-protein-coupled receptor, termed FPR2/ALX. However, direct evidence of the involvement of FPR2/ALX in the anti-inflammatory and proresolution activity of LXA4 is still to be investigated. Here we describe FPR2/ALX trafficking in response to LXA4 and Ac2–26 stimulation. We have transfected cells with HA-tagged FPR2/ALX and studied receptor trafficking in unstimulated, LXA4 (1–10 nM)- and Ac2–26 (30 μM)-treated cells using multiple approaches that include immunofluorescent confocal microscopy, immunogold labeling of cryosections, and ELISA and investigated receptor trafficking in agonist-stimulated phagocytosis. We conclude that PKC-dependent internalization of FPR2/ALX is required for phagocytosis. Using bone marrow-derived macrophages (BMDMs) from mice in which the FPR2/ALX ortholog Fpr2 had been deleted, we observed
- the nonredundant function for this receptor in LXA4 and Ac2–26 stimulated phagocytosis of apoptotic neutrophils.
- LXA4 stimulated phagocytosis 1.7-fold above basal (P<0.001) by BMDMs from wild-type mice, whereas no effect was found on BMDMs from Fpr2−/− mice.
- Ac2–26 stimulates phagocytosis by BMDMs from wild-type mice 1.5-fold above basal (P<0.05), but Ac2–26 failed to stimulate phagocytosis by BMDMs isolated from Fpr2−/− mice.
These data reveal novel and complex mechanisms of the FPR2/ALX receptor trafficking and functionality in the resolution of inflammation.—
Maderna, P., Cottell, D. C., Toivonen, T., Dufton, N., Dalli, J., Perretti, M., Godson, C.
http://www.FASEB.j.org/FPR2/ALX receptor expression and internalization are critical for lipoxin A4 and annexin-derived peptide-stimulated phagocytosis.
We have transfected cells with HA-tagged FPR2/ALX and studied receptor trafficking in unstimulated, LXA4 (1–10 nM)- and Ac2–26 (30 μM)-treated cells using multiple approaches and conclude that PKC-dependent internalization of FPR2/ALX is required for phagocytosis. Using bone marrow-derived macrophages (BMDMs) from mice in which the FPR2/ALX ortholog Fpr2 had been deleted,
- we observed the nonredundant function for this receptor in LXA4 and Ac2–26 stimulated phagocytosis of apoptotic neutrophils.
LXA4 stimulated phagocytosis 1.7-fold above basal (P<0.001) by BMDMs from wild-type mice,
- whereas no effect was found on BMDMs from Fpr2−/− mice.
Ac2–26 stimulates phagocytosis by BMDMs from wild-type mice 1.5-fold above basal (P<0.05)
- Ac2–26 failed to stimulate phagocytosis by BMDMs isolated from Fpr2−/− mice relative to vehicle.
These data reveal novel and complex mechanisms of the FPR2/ALX receptor trafficking and functionality in the resolution of inflammation.
The lipoxin receptor ALX: potent ligand-specific and stereoselective actions in vivo.
Chiang, N., Serhan, CN, Dahlen, SE, Drazen, JM, Hay, DW, Rovati, GE, et al.
Pharmacol. Rev. 2006; 58, 463–487. http://www.PharmacolRev.com/The_lipoxin_receptor_ALX:_potent_ligand_specific_and_stereoselective_actions_in_vivo/
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