S1.5c Proteomics in fungal keratitis research: a road map to personalized treatment

Abstract

S1.5 Mycotic Keratitis, September 21, 2022, 11:00 AM - 12:30 PMResearch becomes very significant and meaningful when it addresses a significant public health problem of a region. Fungal keratitis, ulceration of the cornea due to fungal infection, is one such serious problem. This infection that results in monocular blindness affects primarily the agrarian population and is considered to be a silent epidemic in India.The current treatment for fungal keratitis is the topical application of antifungal drugs such as natamycin and voriconazole. Nearly 40% of the patients do not respond to this treatment and require corneal transplantation. Treatment with antifungal drugs is not a holistic approach as it addresses only killing the fungus. The exaggerated inflammatory response at the site of infection may be a crucial factor in the disease outcome. And, this is not taken into account during the treatment due to the lack of knowledge of the host response during the fungal infection. This was the starting point of our research in fungal keratitis—to understand the corneal immune response to fungal infection.Using mass-spectrometry-based proteomics studies on a tear from keratitis patients, we identified that in response to the fungal infection, the complement and coagulation pathways were activated along with neutrophil-mediated defense responses, notably the neutrophil extracellular traps. These pathways and their cross-talk with each other were primarily responsible for the exaggerated immune response at the site of infection. We selected five tear proteins that were significantly altered and validated them to serve as indicators of the inflammatory status of the ulcer in keratitis patients. Further, we developed a predictive logistic regression model that incorporates tear biomarker levels and ulcer characteristics to identify the subset of patients who are unlikely to respond to the antifungal treatment. We are currently exploring the possibility of using tear-derived EVs or their cargo as adjuvant therapy to modulate the inflammatory response in these non-responder patients.Through our efforts using proteomics approaches, we now have five tear proteins as indicators of the inflammatory status in keratitis patients. These proteins along with the clinical features can identify the subset of patients who are unlikely to respond to antifungal treatment. Additionally, we showed that keratitis patient tear-derived extracellular vesicles are enriched with proteasomes. As proteasomes have an established role in immune modulation, EVs with proteasomes are thus promising candidates for adjuvant therapy, which we are currently exploring. Thus, our journey of over a decade of research on fungal keratitis started with the basic research to understand the host response that in turn provided the leads for translational research, which is now advancing towards personalized treatment for these patients.