arachidonyltrifluoromethane and Acanthamoeba-Keratitis

The aim of this study is to determine if the mannose-induced protein (MIP-133) from Acanthamoeba castellanii trophozoites induces apoptosis of corneal epithelial cells through a cytosolic phospholipase A2α (cPLA2α)-mediated pathway. The efficacy of cPLA2α inhibitors to provide protection against Acanthamoeba keratitis was examined in vivo. Chinese hamster corneal epithelial (HCORN) cells were incubated with or without MIP-133. MIP-133 induces significant increase in cPLA2α and macrophage inflammatory protein-2 (MIP-2/CXCL2) levels from corneal cells. Moreover, cPLA2α inhibitors, MAFP (Methyl-arachidonyl fluorophosphonate) and AACOCF3 (Arachidonyl trifluoromethyl ketone), significantly reduce cPLA2α and CXCL2 from these cells (P < 0.05). Additionally, cPLA2α inhibitors significantly inhibit MIP-133-induced apoptosis in HCORN cells (P < 0.05). Subconjunctival injection of purified MIP-133 in Chinese hamster eyes induced cytopathic effects resulting in corneal ulceration. Animals infected with A. castellanii-laden contact lenses and treated with AACOCF3 and CAY10650, showed significantly less severe keratitis as compared with control animals. Collectively, the results indicate that cPLA2α is involved in MIP-133 induced apoptosis of corneal epithelial cells, polymorphonuclear neutrophil infiltration, and production of CXCL2. Moreover, cPLA2α inhibitors can be used as a therapeutic target in Acanthamoeba keratitis.

Topics: Acanthamoeba castellanii; Acanthamoeba Keratitis; Animals; Apoptosis; Arachidonic Acids; Blotting, Western; Cells, Cultured; Chemokine CXCL2; Chromatography, High Pressure Liquid; Conjunctiva; Cricetinae; Cricetulus; Disease Models, Animal; Enzyme Inhibitors; Enzyme-Linked Immunosorbent Assay; Epithelium, Corneal; Mannose; Organophosphonates; Phospholipases A2, Cytosolic; Protozoan Proteins; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Up-Regulation