Anti-inflammatory mechanisms of the annexin A1 protein and its mimetic peptide Ac2-26 in models of ocular inflammation in vivo and in vitro

Annexin A1 (AnxA1) is a protein that displays potent anti-inflammatory properties, but its expression in eye tissue and its role in ocular inflammatory diseases have not been well studied. We investigated the mechanism of action and potential uses of AnxA1 and its mimetic peptide (Ac2-26) in the endotoxin-induced uveitis (EIU) rodent model and in human ARPE-19 cells activated by LPS. In rats, analysis of untreated EIU after 24 and 48 h or EIU treated with topical applications or with a single s.c. injection of Ac2-26 revealed the anti-inflammatory actions of Ac2-26 on leukocyte infiltration and on the release of inflammatory mediators; the systemic administration of Boc2, a formylated peptide receptor (fpr) antagonist, abrogated the peptide's protective effects. Moreover, AnxA1-/- mice exhibited exacerbated EIU compared with wild-type animals. Immunohistochemical studies of ocular tissue showed a specific AnxA1 posttranslational modification in EIU and indicated that the fpr2 receptor mediated the anti-inflammatory actions of AnxA1. In vitro studies confirmed the roles of AnxA1 and fpr2 and the protective effects of Ac2-26 on the release of chemical mediators in ARPE-19 cells. Molecular analysis of NF-κB translocation and IL-6, IL-8, and cyclooxygenase-2 gene expression indicated that the protective effects of AnxA1 occur independently of the NF-κB signaling pathway and possibly in a posttranscriptional manner. Together, our data highlight the role of AnxA1 in ocular inflammation, especially uveitis, and suggest the use of AnxA1 or its mimetic peptide Ac2-26 as a therapeutic approach. Copyright © 2013 by The American Association of Immunologists, Inc.

Dysregulation of Anti-Inflammatory Annexin A1 Expression in Progressive Crohns Disease

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Deregulation of Annexin-A1 and Galectin-1 Expression in Precancerous Gastric Lesions: Intestinal Metaplasia and Gastric Ulcer

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Inflammation and cancer: role of Annexin A1 and FPR2/ALX in proliferation and metastasis in human laryngeal squamous cell carcinoma

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

The intricate role of mast cell proteases and the annexin A1-FPR1 system in abdominal wall endometriosis

Endometriosis is a continuous and progressive disease with a poorly understood aetiology, pathophysiology and natural history. This study evaluated the histological differences between eutopic and ectopic endometria (abdominal wall endometriosis) and the expression of mast cell proteases (tryptase and chymase), annexin A1 (ANXA1) and formyl peptide receptor 1 (FPR1). Ectopic endometrium from 18 women with abdominal wall endometriosis and eutopic endometrium from 10 women without endometriosis were obtained. The endometrial samples were analysed by histopathology, immunohistochemistry and ultrastructural immunogold labeling to determine mast cell heterogeneity (tryptase and chymase positive cells) and the expression levels of ANXA1 and FPR1. Histopathological analysis of the endometriotic lesions showed a glandular pattern of mixed differentiation and an undifferentiated morphology with a significant influx of inflammatory cells and a change in mast cell heterogeneity, as evidenced by a significant increase in the number of chymase-positive cells and endogenous chymase expression. The undifferentiated glandular pattern of endometriotic lesions was positively associated with a marked increase and co-localization of ANXA1 and FPR1 in the epithelial cells. In conclusion, the co-upregulated expression of mast cell chymase and ANXA1–FPR1 system in ectopic endometrium suggests their involvement in the development of endometriotic lesions.

The essential role of annexin A1 mimetic peptide in the skin allograft survival

Immunosuppressive drugs have a critical role in inhibiting tissue damage and allograft rejection.Studies have demonstrated the anti-infl ammatory effects of the annexin A1 (AnxA1) in the regulationof transmigration and apoptosis of leucocytes. In the present study, an experimental skin allograftmodel was used to evaluate a potential protective effect of AnxA1 in transplantation survival. Micewere used for the skin allograft model and pharmacological treatments were carried out using eitherthe AnxA1 mimetic peptide Ac2-26, with or without cyclosporine A (CsA), starting 3 days beforesurgery until rejection. Graft survival, skin histopathology, leucocyte transmigration and expressionof AnxA1 and AnxA5 post-transplantation were analysed. Pharmacological treatment with Ac2-26increased skin allograft survival related with inhibition of neutrophil transmigration and inductionof apoptos is, thereby reducing the tissue damage compared with control animals. Moreover, AnxA1and AnxA5 expression increased after Ac2-26 treatment in neutrophils. Interestingly, thecombination of Ac2-26 and cyclosporine A showed similar survival of transplants when compared withthe cyclosporine A group, which could be attributed to a synergistic effect of both drugs. Investigationsin vitro revealed that cyclosporine A inhibited extracellular-signal-regulated kinase (ERK) phosphory-lation induced by Ac2-26 in neutrophils. Overall, the results suggest that AnxA1 has an essential role inaugmenting the survival of skin allograft, mainly owing to inhibition of neutrophil transmigration andenhancement of apoptosis. This effect may lead to the development of new therapeutic approachesrelevant to transplant rejection.

Beneficial effect of annexin A1 in a model of experimental allergic conjunctivitis

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Ac2-26 mimetic peptide of annexin A1 inhibits local and systemic inflammatory processes induced by bothrops moojeni venom and the lys-49 phospholipase A2 in a rat model

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Annexin A1 regulates neutrophil clearance by macrophages in the mouse bone marrow

Under homeostatic conditions, a proportion of senescent CXCR4(hi) neutrophils home from the circulation back to the bone marrow, where they are phagocytosed by bone marrow macrophages. In this study, we have identified an unexpected role for the anti-inflammatory molecule annexin A1 (AnxA1) as a critical regulator of this process. We first observed that AnxA1(-/-) mice have significantly increased neutrophil numbers in their bone marrow while having normal levels of GM and G colony-forming units, monocytes, and macrophages. Although AnxA1(-/-) mice have more neutrophils in the bone marrow, a greater proportion of these cells are senescent, as determined by their higher levels of CXCR4 expression and annexin V binding. Consequently, bone marrow neutrophils from AnxA1(-/-) mice exhibit a reduced migratory capacity in vitro. Studies conducted in vitro also show that expression of AnxA1 is required for bone marrow macrophages, but not peritoneal macrophages, to phagocytose apoptotic neutrophils. Moreover, in vivo experiments indicate a defect in clearance of wild-type neutrophils in the bone marrow of AnxA1(-/-) mice. Thus, we conclude that expression of AnxA1 by resident macrophages is a critical determinant for neutrophil clearance in the bone marrow.-Dalli, J., Jones, C. P., Cavalcanti, D. M., Farsky, S. H., Perretti, M., Rankin, S. M. Annexin A1 regulates neutrophil clearance by macrophages in the mouse bone marrow. FASEB J. 26, 387-396 (2012). www.fasebj.org

Annexin A1 protein attenuates cyclosporine-induced renal hemodynamics changes and macrophage infiltration in rats

Cyclosporine (CsA) remains an important immunosuppressant for transplantation and for treatment of autoimmune diseases. The most troublesome side effect of CsA is renal injury. Acute CsA-induced nephrotoxicity is characterized by reduced renal blood flow (RBF) and glomerular filtration rate (GFR) due to afferent arteriole vasoconstriction. Annexin A1 (ANXA1) is a potent anti-inflammatory protein with protective effect in renal ischemia/reperfusion injury. Here we study the effects of ANXA1 treatment in an experimental model of acute CsA nephrotoxicity. Salt-depleted rats were randomized to treatment with VH (vehicles 1 mL/kg body weight/day), ANXA1 (Ac2-26 peptide 1 mg/kg body weight/day intraperitoneally), CsA (20 mg/kg body weight/day subcutaneously) and CsA + ANXA1 (combination) for seven days. We compared renal function and hemodynamics, renal histopathology, renal tissue macrophage infiltration and renal ANXA1 expression between the four groups. CsA significantly impaired GFR and RBF, caused tubular dilation and macrophage infiltration and increased ANXA1 renal tissue expression. Treatment with ANXA1 attenuated CSA-induced hemodynamic changes, tubular injury and macrophage infiltration. ANXA1 treatment attenuated renal hemodynamic injury and inflammation in an acute CsA nephrotoxicity model.

Annexin-A1 peptide down-regulates the leukocyte recruitment and up-regulates interleukin-10 release into lung after intestinal ischemia-reperfusion in mice

Abstract Background Intestinal ischemia/reperfusion (IR) injury is a serious and triggering event in the development of remote organ dysfunction, from which the lung is the main target. This condition is characterized by intense neutrophil recruitment, increased microvascular permeability. Intestinal IR is also responsible for induction of adult respiratory distress syndrome, the most serious and life-threatening form of acute lung injury. The purpose of this study was to investigate the effect of annexin-A1 protein as an endogenous regulator of the organ remote injury induced by intestinal ischemia/reperfusion. Male C57bl/6 mice were subjected to intestinal ischemia, induced by 45 min occlusion of the superior mesenteric artery, followed by reperfusion. Results The intestinal ischemia/reperfusion evoked a high intensity lung inflammation as indicated by the number of neutrophils as compared to control group. Treatment with annexin-A1 peptidomimetic Ac2-26, reduced the number of neutrophils in the lung tissue and increased its number in the blood vessels, which suggests a regulatory effect of the peptide Ac2-26 in the neutrophil migration. Moreover, the peptide Ac2-26 treatment was associated with higher levels of plasma IL-10. Conclusion Our data suggest that the annexin-A1 peptidomimetic Ac2-26 treatment has a regulatory and protective effect in the intestinal ischemia/reperfusion by attenuation of the leukocyte migration to the lung and induction of the anti-inflammatory cytokine IL-10 release into the plasma. The anti-inflammatory action of annexin-A1 and its peptidomimetic described here may serve as a basis for future therapeutic approach in mitigating inflammatory processes due to intestinal ischemia/reperfusion.

Annexin-A1 peptide down-regulates the leukocyte recruitment and up-regulates interleukin-10 release into lung after intestinal ischemia-reperfusion in mice

BACKGROUND: Intestinal ischemia/reperfusion (IR) injury is a serious and triggering event in the development of remote organ dysfunction, from which the lung is the main target. This condition is characterized by intense neutrophil recruitment, increased microvascular permeability. Intestinal IR is also responsible for induction of adult respiratory distress syndrome, the most serious and life-threatening form of acute lung injury. The purpose of this study was to investigate the effect of annexin-A1 protein as an endogenous regulator of the organ remote injury induced by intestinal ischemia/reperfusion. Male C57bl/6 mice were subjected to intestinal ischemia, induced by 45 min occlusion of the superior mesenteric artery, followed by reperfusion. RESULTS: The intestinal ischemia/reperfusion evoked a high intensity lung inflammation as indicated by the number of neutrophils as compared to control group. Treatment with annexin-A1 peptidomimetic Ac2-26, reduced the number of neutrophils in the lung tissue and increased its number in the blood vessels, which suggests a regulatory effect of the peptide Ac2-26 in the neutrophil migration. Moreover, the peptide Ac2-26 treatment was associated with higher levels of plasma IL-10. CONCLUSION: Our data suggest that the annexin-A1 peptidomimetic Ac2-26 treatment has a regulatory and protective effect in the intestinal ischemia/reperfusion by attenuation of the leukocyte migration to the lung and induction of the anti-inflammatory cytokine IL-10 release into the plasma. The anti-inflammatory action of annexin-A1 and its peptidomimetic described here may serve as a basis for future therapeutic approach in mitigating inflammatory processes due to intestinal

Fluorescent annexin A1 reveals dynamics of ceramide platforms in living cells

Upon its genesis during apoptosis, ceramide promotes gross reorganization of the plasma membrane structure involving clustering of signalling molecules and an amplification of vesicle formation, fusion and trafficking. The annexins are a family of proteins, which in the presence of Ca(2+), bind to membranes containing negatively charged phospholipids. Here, we show that ceramide increases affinity of annexin A1-membrane interaction. In the physiologically relevant range of Ca(2+) concentrations, this leads to an increase in the Ca(2+)sensitivity of annexin A1-membrane interaction. In fixed cells, using a ceramide-specific antibody, we establish a direct interaction of annexin A1 with areas of the plasma membrane enriched in ceramide (ceramide platforms). In living cells, the intracellular dynamics of annexin A1 match those of plasmalemmal ceramide. Among proteins of the annexin family, the interaction with ceramide platforms is restricted to annexin A1 and is conveyed by its unique N-terminal domain. We demonstrate that intracellular Ca(2+)overload occurring at the conditions of cellular stress induces ceramide production. Using fluorescently tagged annexin A1 as a reporter for ceramide platforms and annexin A6 as a non-selective membrane marker, we visualize ceramide platforms for the first time in living cells and provide evidence for a ceramide-driven segregation and internalization of membrane-associated proteins.