ABSTRACT
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.
Subject(s)
Annexin A1/genetics , Anti-Inflammatory Agents/pharmacology , Peptides/pharmacology , Uveitis/genetics , Animals , Annexin A1/administration & dosage , Annexin A1/chemistry , Annexin A1/metabolism , Annexin A1/pharmacology , Anti-Inflammatory Agents/administration & dosage , Aqueous Humor/cytology , Aqueous Humor/immunology , Cyclooxygenase 2/genetics , Cyclooxygenase 2/metabolism , Cytokines/biosynthesis , Cytokines/genetics , Cytokines/immunology , Disease Models, Animal , Endotoxins/adverse effects , Gene Expression Regulation/drug effects , Lipopolysaccharides/immunology , Male , Mice , Mice, Knockout , Models, Biological , NF-kappa B/metabolism , Neutrophil Infiltration/immunology , Neutrophils/drug effects , Neutrophils/immunology , Oligopeptides/pharmacology , Peptides/administration & dosage , Phosphorylation , Protein Transport/drug effects , Rats , Receptors, Formyl Peptide/genetics , Receptors, Formyl Peptide/metabolism , Uveitis/chemically induced , Uveitis/immunologyABSTRACT
A series of 3-(triazolyl)-coumarins were synthesized and tested as anti-inflammatory agents. It was possible to infer that these compounds do not alter the interaction of LPS with TLR-4 or TLR-2, as the intracellular pathways involved in the TNF-α secretion and COX-2 activity were not affected. Nevertheless, the compounds inhibited iNOS-derived NO production, without affecting the eNOS activity. The outcome of the docking studies showed that π···π interactions with the heme group are important for the iNOS inhibition, thus making compound 3c a promising lead. Moreover, the efficacy of this compound was visualized by the reduced number of neutrophils in the LPS-inflamed subcutaneous tissue. Together, biological and docking data show that triazolyl-substituted coumarins, that can act on iNOS, are a good scaffold to be explored.
