Altered expression of genes related to innate antifungal immunity in the absence of galectin-3

Galectin-3 Is a Crucial Immunological Disease Marker in Patients with Fungal Keratitis

Fungal keratitis, one of the most common infectious eye diseases in China, often results in a poor prognosis due to a delayed diagnosis and the insufficiency of effective therapy. There is an urgent need to identify specific biomarkers for the disease. In this study, we screened out tear proteins in patients with fungal keratitis by microsphere-based immunoassay analysis. Levels of cytokine expression were determined in both human corneal epithelial cell models in vitro and the corneas of patients by western blot, quantitative polymerase chain reaction (qPCR), and immunofluorescence analysis. Neutrophil activation was examined by flow cytometry analysis. The relationship between the cytokine expression and neutrophils was evaluated by immunofluorescence costaining and correlation analysis. These results demonstrated that the galectin-3 expression level was increased in both cell model and patient samples at the early and late stages of fungal keratitis. The neutrophils were significantly activated during the disease course of fungal keratitis. Meanwhile, colocalization and a positive correlation between galectin-3 and neutrophils were observed, suggesting that galectin-3 may play a crucial role in the recruitment of neutrophils and immune regulation of fungal keratitis. In conclusion, galectin-3 could be a key disease marker implying a beneficial immune response in the pathogenesis of fungal keratitis, which might be a target of therapeutic strategy in the future.

Influence of Galectin-3 on the Innate Immune Response during Experimental Cryptococcosis

Cryptococcus neoformans, the causative agent of cryptococcosis, is the primary fungal pathogen that affects the immunocompromised individuals. Galectin-3 (Gal-3) is an animal lectin involved in both innate and adaptive immune responses. The present study aimed to evaluate the influence of Gal-3 on the C. neoformans infection. We performed histopathological and gene profile analysis of the innate antifungal immunity markers in the lungs, spleen, and brain of the wild-type (WT) and Gal-3 knockout (KO) mice during cryptococcosis. These findings suggest that Gal-3 absence does not cause significant histopathological alterations in the analyzed tissues. The expression profile of the genes related to innate antifungal immunity showed that the presence of cryptococcosis in the WT and Gal-3 KO animals, compared to their respective controls, promoted the upregulation of the pattern recognition receptor (PRR) responsive to mannose/chitin (mrc1) and a gene involved in inflammation (ccr5), as well as the downregulation of the genes related to signal transduction (card9, fos, ikbkb, jun) and PRRs (cd209a, colec12, nptx1). The absence of Gal-3, in fungal infection, a positively modulated gene involved in phagocytosis (sftpd) and negatively genes involved in signal transduction (syk and myd88), proinflammatory cytokines il-1β and il-12b and cd209a receptor. Therefore, our results suggest that Gal-3 may play an essential role in the development of antifungal immune responses against cryptococcosis.