The Pathogenesis of Aspergillus Keratitis

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DESCRIPTION (provided by applicant): The incidence of human fungal infections has steadily increased over the past few decades. Though associated with an increased immunosuppressed population size, not all fungal infections necessitate an immunocompromised hosts. This is especially true for filamentous fungal infections of the cornea (i.e keratitis), in which the majority of patients are fully immunocompetent. Indeed, in such cases the etiology of corneal pathology is due to an excessive inflammatory response to the invading organism, not the infection itself. During Aspergillus keratitis, the inflammation can be so severe that 42-60% of infections end with corneal transplantation. Before such bleak clinical outcomes improve, we must invest in research to better understand the mediators of host-fungai interactions. This proposal will utilize a murine corneal infection model (i.e Aspergillus keratitis) to address gaps in our current understanding of in vivo host-mycelia interactions. Using this model, we will address the hypothesis that specific pathogen recognition receptors on resident macrophages mediate neutrophil recruitment into the cornea during Aspergillus keratitis (AIM 1). In AIM 2 we will address the hypothesis that similar receptors on infiltrating neutrophils mediate A. fumigatus hyphal killing. Lastly, in AIM 3 we will address the hypothesis that the fungal secondary metabolite, gliotoxin, mediates fungal survival and enhanced corneal pathology during Aspergillus keratitis through inhibition of reactive oxygen species formation by infiltrating neutrophils. The studies proposed herein will greatly expand our understanding of host-mycelial interactions in the cornea, while identifying anti-inflammatory and anti-fungal targets for therapeutic intervention during Aspergillus keratitis. Lay Language: The goal of this proposal is to identify potential anti-inflammatory and anti-fungal therapeutic targets during Aspergillus fumigatus infection in the cornea. We propose to do this by using mouse models of A. fumigatus corneal infection to study the innate immune receptors required for recognition and killing of this fungus, as well as the mechanism by which A.fumigatus evades fungal killing during corneal infection.