Comparative cytotoxicity of Acanthamoeba castellanii-derived conditioned medium on human corneal epithelial and stromal cells

• Published in: Acta tropica 2024-09, Vol.257, p.107288, Article 107288
• Main Authors: Alhazmi, Abdullah, Sidney, Laura E., Hopkinson, Andy, Elsheikha, Hany M.
• Format: Article
• Language: English
• Subjects: Acanthamoeba castellanii; Actin cytoskeleton; Corneal epithelial cells; Corneal stromal cells; Cytotoxicity; Metabolic activity
• ISSN: 0001-706X; 1873-6254; 1873-6254
• DOI: 10.1016/j.actatropica.2024.107288

•Acanthamoeba castellanii conditioned medium (ACCM) had cytotoxic effects.•ACCM induced pro-apoptotic effects on corneal cells.•Corneal epithelial cells had more cytotoxicity than primary corneal stromal cells.•ACCM altered corneal cell cytoskeletal and ultrastructural compartments.•The cytopathogenic activities exhibited by ACCM were mediated by proteases. Soluble factors in the secretome of Acanthamoeba castellanii play crucial roles in the pathogenesis of Acanthamoeba keratitis (AK). Investigating the pathological effects of A. castellanii-derived conditioned medium (ACCM) on ocular cells can provide insights into the damage inflicted during AK. This study examined ACCM-induced cytotoxicity in primary human corneal stromal cells (CSCs) and a human SV40 immortalized corneal epithelial cell line (ihCECs) at varying ACCM concentrations (25 %, 50 %, 75 %, and 100 %). MTT, AlamarBlue, Sulforhodamine B, lactate dehydrogenase, and Caspase-3/7 activation assays were used to assess the impact of ACCM on the cell viability, proliferation and apoptosis. Additionally, fluorescent staining was used to reveal actin cytoskeleton changes. ACCM exposure significantly decreased cell viability, increased apoptosis, and disrupted the actin cytoskeleton, particularly at higher concentrations and longer exposures. Proteases were found to mediate these cytopathogenic effects, highlighting the need for characterization of A. castellanii proteases as key virulence factors in AK pathogenesis.