The involvement of anti-inflammatory protein, Annexin A1, in ocular toxoplasmosis

Purpose: The aim of this study was to evaluate the expression of the protein annexin A1 (ANXA1), a potent endogenous regulator of the inflammatory process, in ocular toxoplasmosis. Methods: C57BL/6 female mice were infected using intravitreal injections of either 10 6 tachyzoites of Toxoplasma gondii (RH strain; T. gondii) or PBS only (control groups). After 24, 48, and 72 h, animals were sacrificed and their eyes were harvested for histopathological, immunohistochemical, and ultrastructural immunocytochemical analysis of ANXA1. Human retinal pigment epithelial (RPE) cells (ARPE-19) were infected in vitro with T. gondii and collected after 60, 120, 240 min, and 24 h. Results: Compared with non-infected eyes, an intense inflammatory response was observed in the anterior (24 h after infection) and posterior segments (72 h after infection) of the infected eye, characterized by neutrophil infiltration and by the presence of tachyzoites and their consequent destruction along with disorganization of normal retina architecture and RPE vacuolization. T. gondii infection was associated with a significant increase of ANXA1 expression in the neutrophils at 24, 48, and 72 h, and in the RPE at 48 and 72 h. In vitro studies confirmed an upregulation of ANXA1 levels in RPE cells, after 60 and 120 min of infection with T. gondii. Conclusions: The positive modulation of endogenous ANXA1 in the inflammatory and RPE cells during T. gondii infection suggests that this protein may serve as a therapeutic target in ocular toxoplasmosis. © 2012 Molecular Vision

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 (AnxAl) 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 AnxAl 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 AnxAl posttranslational modification in EIU and indicated that the fpr2 receptor mediated the anti-inflammatory actions of AnxAl. in vitro studies confirmed the roles of AnxAl and fpr2 and the protective effects of Ac2-26 on the release of chemical mediators in ARPE-19 cells. Molecular analysis of NF-kappa B translocation and IL-6, IL-8, and cyclooxygenase-2 gene expression indicated that the protective effects of AnxAl occur independently of the NF-kappa B signaling pathway and possibly in a posttranscriptional manner. Together, our data highlight the role of AnxAl in ocular inflammation, especially uveitis, and suggest the use of AnxAl or its mimetic peptide Ac2-26 as a therapeutic approach.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)São Paulo State Univ, Inst Biociencias Letras & Ciencias Exatas, Dept Biol, BR-15054000 Sao Jose Do Rio Preto, BrazilIntegrated Coll Padre Albino Fdn, Dept Phys & Biol Sci, BR-15809144 Catanduva, SP, BrazilUniversidade Federal de São Paulo, Postgrad Struct & Funct Biol, BR-04023900 São Paulo, BrazilUniv São Paulo, Dept Clin & Toxicol Anal, BR-05508900 São Paulo, BrazilQueen Mary Univ London, Barts & London Sch Med & Dent, William Harvey Res Inst, London EC1M 6BQ, EnglandUniversidade Federal de São Paulo, Dept Morphol & Genet, BR-04023900 São Paulo, BrazilUniversidade Federal de São Paulo, Postgrad Struct & Funct Biol, BR-04023900 São Paulo, BrazilUniversidade Federal de São Paulo, Dept Morphol & Genet, BR-04023900 São Paulo, BrazilFAPESP: 2011/00128-1FAPESP: 2009/15240-1CNPq: 472056/2009-3CNPq: 301677/2011-5Web of Scienc

Correction: Inflammation in Sickle Cell Disease: Differential and Down-Expressed Plasma Levels of Annexin A1 Protein.

[This corrects the article DOI: 10.1371/journal.pone.0165833.]

Characterization of the study groups.

<p>Characterization of the study groups.</p

Plasma levels of the proinflammatory cytokines in the control group and SCD genotypes.

<p>(A) IL-1β. (B) IL-8. (C) TNF-α. Data expressed in mean ± standard error of the mean. Statistical analysis: <i>one-way ANOVA</i>. *p<0.05 for <i>Tukey-Krumer post hoc</i>. ^#<i>Dunnett’s post hoc</i> (^#p<0.05. ^##p < 0.01. ^###p < 0.001).</p

Hemolytic status in the SCD genotypes.

<p>(A) Reticulocytes. (B) LDH. (C) AST. (D) UCB. LDH: lactate dehydrogenase. AST: aspartate aminotransferase. UCB: unconjugated bilirubin. U/L: unit per liter. mm/dL: millimeter per deciliter. Reference values: Reticulocytes (1.0–2.6%); LDH (< 480 U/L); AST (< 31 U/L); UCB (< 0.7 mm/dL). Statistical analysis: <i>Kruskal-Wallis</i> followed by <i>Dunn’s</i> test for A and B; <i>one-way ANOVA</i> followed by <i>Tukey’s</i> test for C and D. *p < 0.05. ***p < 0.001.</p

Plasma levels of the proinflammatory cytokines in the control and SCD groups.

<p>(A) IL-1β. (B) IL-8. (C) TNF-α. Data expressed in mean ± standard error of the mean. Statistical analysis: Student t-test. *p < 0.05. **p < 0.01. ***p < 0.001.</p

Hematological profile of the SCD genotypes.

<p>Hematological profile of the SCD genotypes.</p