Nf-GH, a glycosidase secreted by Naegleria fowleri, causes mucin degradation: an in vitro and in vivo study

Aim: The aim of this work was to identify, characterize and evaluate the pathogenic role of mucinolytic activity released by Naegleria fowleri. Materials & methods: Zymograms, protease inhibitors, anion exchange chromatography, MALDI-TOF-MS, enzymatic assays, Western blot, and confocal microscopy were used to identify and characterize a secreted mucinase; inhibition assays using antibodies, dot-blots and mouse survival tests were used to evaluate the mucinase as a virulence factor. Results: A 94-kDa protein with mucinolytic activity was inducible and abolished by p-hydroxymercuribenzoate. MALDI-TOF-MS identified a glycoside hydrolase. Specific antibodies against N. fowleri-glycoside hydrolase inhibit cellular damage and MUC5AC degradation, and delay mouse mortality. Conclusion: Our findings suggest that secretory products from N. fowleri play an important role in mucus degradation during the invasion process.