 |
|
 |
Ac2-26 References
|
Endogenous lipid- and peptide-derived anti-inflammatory pathways generated with
glucocorticoid and aspirin treatment activate the lipoxin A(4) receptor Aspirin (ASA) and dexamethasone (DEX) are widely used anti-inflammatory agents yet their mechanism(s) for blocking polymorphonuclear neutrophil (PMN) accumulation at sites of inflammation remains unclear. Here, we report that inhibition of PMN infiltration by ASA and DEX is a property shared by aspirin-triggered lipoxins (ATL) and the glucocorticoid-induced annexin 1 (ANXA1)-derived peptides that are both generated in vivo and act at the lipoxin A(4) receptor (ALXR/FPRL1) to halt PMN diapedesis. These structurally diverse ligands specifically interact directly with recombinant human ALXR demonstrated by specific radioligand binding and function as well as immunoprecipitation of PMN receptors. In addition, the combination of both ATL and ANXA1-derived peptides limited PMN infiltration and reduced production of inflammatory mediators (that is, prostaglandins and chemokines) in vivo. Together, these results indicate functional redundancies in endogenous lipid and peptide anti-inflammatory circuits that are spatially and temporally separate, where both ATL and specific ANXA1-derived peptides act in concert at ALXR to downregulate PMN recruitment to inflammatory loci. Perretti M, et al. Nat Med 2002 Nov;8(11):1296-302 |
|
Anti-inflammatory lipocortin-derived peptides.
Peptide Ac2-26, drawn from the sequence of human lipocortin 1, inhibited the release of elastase activity from cytoplasmic granules of human neutrophils, and neutrophil adhesion to monolayers of endothelial cells, in a concentration-dependent manner (approximate IC50 of 100 micrograms/ml, 33 microM). The effect of peptide Ac2-26 was not restricted to a specific neutrophil activator, being effective against formyl-Met-Leu-Phe (FMLP), leukotriene B4 (LTB4) and platelet-activating factor (PAF). Peptide Ac2-26 did not alter FMLP binding to its receptor. These in vitro observations complement in vivo data obtained with this peptide and may enable a better understanding of its pharmacology and, perhaps, that of of lipocortin 1 too. Perretti M, Flower RJ. Agents Actions Suppl 1995;46:131-8 |
|
Annexin 1 peptides protect against experimental myocardial ischemia-reperfusion: analysis of their mechanism of action Myocardial reperfusion injury is associated with the infiltration of blood-borne polymorphonuclear leukocytes. We have previous described the protection afforded by annexin 1 (ANXA1) in an experimental model of rat myocardial ischemia-reperfusion (IR) injury. We examined the 1) amino acid region of ANXA1 that retained the protective effect in a model of rat heart IR; 2) changes in endogenous ANXA1 in relation to the IR induced damage and after pharmacological modulation; and 3) potential involvement of the formyl peptide receptor (FPR) in the protective action displayed by ANXA1 peptides. Administration of peptide Ac2-26 at 0, 30, and 60 min postreperfusion produced a significant protection against IR injury, and this was associated with reduced myeloperoxidase activity and IL-1beta levels in the infarcted heart. Western blotting and electron microscopy analyses showed that IR heart had increased ANXA1 expression in the injured tissue, associated mainly with the infiltrated leukocytes. Finally, an antagonist to the FPR receptor selectively inhibited the protective action of peptide ANXA1 and its derived peptides against IR injury. Altogether, these data provide further insight into the protective effect of ANXA1 and its mimetics and a rationale for a clinical use for drugs developed from this line of research.-La, M., D'Amico, M., Bandiera, S., Di Filippo, C., Oliani, S. M., Gavins, F. N. E., Flower, R. J., Perretti, M. Annexin 1 peptides protect against experimental myocardial ischemia-reperfusion: analysis of their mechanism of action. La M,, et al. FASEB J 2001 Oct 1;15(12):2247-2256 |
|
An annexin 1 (ANXA1)-derived peptide inhibits prototype antigen-driven human T cell Th1 and Th2 responses in vitro. BACKGROUND: Annexin-1 (ANXA1, lipocortin 1) is a pleiotrophic protein produced by many cell types including peripheral blood leucocytes. Although it has been shown to inhibit "macroscopic" inflammatory processes in animal models, its direct effects on antigen-activated human T cells have not been studied. OBJECTIVE: To test the hypothesis that ANXA1-derived peptides inhibit antigen-driven prototype Th1 and Th2-type human T cell responses of clinical relevance and lectin-driven responses in vitro. METHODS: Peripheral blood mononuclear cells (PBMC) were isolated from 14 atopic subjects sensitized to house dust mite allergen (Dermatophagoides pteronyssinus, Der p) and purified protein derivative (PPD) of Mycobacterium tuberculosis. PBMC (1 x 106/mL) were cultured with phytohaemagglutinin (PHA; 5 microg/mL; 4 days), Der p (25 microg/mL; 6 days), PPD (10 microg/mL, 6 days) or medium control. Two ANXA1-derived peptides, Ac2-26 and AF-2 (5-500 microM), were assessed for possible inhibition of PHA-and antigen-induced T cell proliferation (measured by 3H-thymidine uptake), while Ac2-26 was assessed for inhibition of Der p-induced interleukin (IL)-5 release and PPD-induced interferon-gamma (IFN-gamma) release (measured by ELISA). Comparison was made with dexamethasone as an established inhibitory control. Endogenous production by PBMC of cell surface-associated and intracellular ANXA1 in response to PHA, Der p and PPD in the presence and absence of dexamethasone was measured by specific ELISA. RESULTS: Both PHA- and antigen-induced T cellular proliferation were inhibited by dexamethasone. Although neither ANXA1-derived peptide significantly altered PHA-induced proliferation, both effected concentration-dependent reductions in antigen-induced proliferation, Ac2-26 being the more potent. Peptides of identical amino acid composition to Ac2-26 and AF-2, but of random sequence, were ineffective at equivalent concentrations. In addition, Ac2-26 and dexamethasone inhibited Der p-induced IL-5 release and PPD-induced IFN-gamma release in a concentration-dependent fashion. Endogenous ANXA1 was detectable in PBMC, but at concentrations approximately 104-fold lower, in molar terms, than the effective concentrations of the exogenously added, ANXA1-derived inhibitory peptides. Endogenous production was not significantly altered by any of the T cell stimuli employed in this study, in the presence or absence of dexamethasone. CONCLUSION: In prototype Th1 and Th2-type human T cell responses, ANXA1-derived peptides can inhibit antigen-driven cellular proliferation and cytokine production. Kamal AM, et al. Clin Exp Allergy 2001 Jul;31(7):1116-25 |
|
Involvement of the receptor for formylated
peptides in the in vivo anti-migratory actions of annexin 1 and its mimetics.
An innovative avenue for anti-inflammatory therapy is inhibition of neutrophil extravasation by potentiating the action of endogenous anti-inflammatory mediators. The glucocorticoid-inducible protein annexin 1 and derived peptides are effective in inhibiting neutrophil extravasation. Here we tested the hypothesis that an interaction with the receptor for formylated peptide (FPR), so far reported only in vitro, could be the mechanism for this in vivo action. In a model of mouse peritonitis, FPR antagonists abrogated the anti-migratory effects of peptides Ac2-26 and Ac2-12, with a partial reduction in annexin 1 effects. A similar result was obtained in FPR (knock-out) KO mice. Binding of annexin 1 to circulating leukocytes was reduced (>50%) in FPR KO mice. In vitro, annexin binding to peritoneal macrophages was also markedly reduced in FPR KO mice. Finally, evidence of direct annexin 1 binding to murine FPR was obtained with HEK-293 cells transfected with the receptor. Overall, these results indicate a functional role for FPR in the anti-migratory effect of annexin 1 and derived peptides. Perretti M, et al. Am J Pathol 2001 Jun;158(6):1969-73 |
|
Differential modulation of annexin I binding
sites on monocytes and neutrophils.
Specific binding sites for the anti-inflammatory protein annexin I have been detected on the surface of human monocytes and polymorphonuclear leukocytes (PMN). These binding sites are proteinaceous in nature and are sensitive to cleavage by the proteolytic enzymes trypsin, collagenase, elastase and cathepsin G. When monocytes and PMN were isolated independently from peripheral blood, only the monocytes exhibited constitutive annexin I binding. However PMN acquired the capacity to bind annexin I following co-culture with monocytes. PMN incubation with sodium azide, but not protease inhibitors, partially blocked this process. A similar increase in annexin I binding capacity was also detected in PMN following adhesion to endothelial monolayers. We propose that a juxtacrine activation rather than a cleavage-mediated transfer is involved in this process. Removal of annexin I binding sites from monocytes with elastase rendered monocytes functionally insensitive to full length annexin I or to the annexin I-derived pharmacophore, peptide Ac2-26, assessed as suppression of the respiratory burst. These data indicate that the annexin I binding site on phagocytic cells may have an important function in the feedback control of the inflammatory response and their loss through cleavage could potentiate such responses. Euzger HS, et al. Mediators Inflamm 1999;8(1):53-62 |