\(Fusarium\) Keratitis in a 3D Hemi-Cornea Model

Filamentous fungi can cause severe and hard-to-treat keratitis infections within humans. Opportunistic pathogenic species belonging to the Fusarium solani species complex are causative for a notable proportion of global keratitis cases. In western countries with temperate climate the infections are mainly associated with the wearing of contact lenses or with contact lens-associated material. In warmer and more humid areas, like southeast Asia, Fusarium keratitis is mostly caused by plant-derived injuries in agriculture. Current therapeutic options often fail to achieve the desired clinical outcome. In numerous cases keratoplastic surgery or even the enucleation of the eye is inevitable. The knowledge of underlying mechanisms during the infection process, as well as the genetic background of the pathogenic Fusarium species, is, to date, largely unknown. Findings in this area can set a basis for future improvements of treatment options and success for the patients. F. falciforme, F. petroliphilum and F. keratoplasticum belong to the most common FSSC keratitis pathogens. The cellular as well as the tissue infection process was simulated within an immortalized human cornea epithelial cell line and a 3D hemi-cornea model. Fluorescence and transmission electron microscopy (TEM) was used for visualization of the results. The cellular damage as well as immune reaction was further investigated. To do so, the release of lactate dehydrogenase as well as multiple cytokines was utilized. F. keratoplasticum showed increased pathogenicity within infection models. A significantly elevated cellular damage and an increased proportion of infected tissue were found in the 3D hemi-cornea models. The exclusive development of transcellular tunnels on immortalized human cornea epithelial cells was identified via TEM. Additionally, de novo genome and transcriptome data of human F. petroliphilum and F. keratoplasticum keratitis isolates were compared via PacBio and Illumina sequencing. The de novo genome sequencings revealed an overall genome length between 47.9 and 51.2 Mbp. Furthermore, new therapeutic strategies were tested by the investigation of nanogels as a delivery system for antimycotics, to improve the susceptibility of FSSC species towards the available antifungal drugs. The binding and potential efficacy were assessed via fluorescence microscopy. These first investigations of new therapeutic options revealed a clear binding ability of polyglycidol nanogels on FSSC hyphae. The findings within this work set a meaningful basis, which will lead to an improved understanding and optimization of treatment options for Fusarium keratitis in the future.