Poster ID: EPSCOR0022 - Anti-Fungal Activity

Anti-Fungal Activity of Lysosomal Proteins and their Effects on Cryptococcus neoformans

Sierra X. Posey, B. Nelson and K. L. Wozniak, Dept. of Microbiology and Molecular Genetics, Oklahoma State University, Stillwater, OK. Faculty Advisor, Dr. Karen Wozniak Oklahoma State University, Stillwater, OK.

ABSTRACT

Cryptococcus neoformans is an opportunistic fungal infection spread through airborne means. It affects immune compromised individuals such as people with HIV/AIDS and increases their susceptibility to the disease. Infected individuals become sick with Cryptococcal meningitis and have high mortality rates. Previous studies showed that dendritic cells (DCs) can kill Cryptococcus through phagocytosis and lysosomal killing from within the DC. The lysosomal extract from these DCs has anti-cryptococcal activity, and we now have mass spectrometry data identifying its contents. We hypothesized that DC lysosomal proteins nostrin, calmodulin, and coronin 1a have anti-fungal activity against C. neoformans. For these studies, we incubated lysosomal extract of these individual proteins with C. neoformans to measure anti-fungal activity. Our results showed nostrin and coronin-1A had significant antifungal activity, while calmodulin significantly increased cryptococcal growth. Cytotoxicity was tested in nostrin and it was not toxic to mammalian cells. Because calmodulin increased cryptococcal growth, we hypothesized that following incubation with C. neoformans, the media contained growth- enhancing nutrients. For this, we examined the media for macronutrients, amino acids, and metals following incubation of C. neoformans with calmodulin and other growth-enhancing lysosomal proteins S100A6, cystatin B, calnexin, striatin, and CRISP-1. We found that incubation of C. neoformans with calmodulin, cystatin B, and CRISP-1 led to increased biotin in the media, and trace elements including Cd, Fe, Mn were also increased following incubation of C. neoformans with calmodulin. Interestingly, some compounds alone increased trace metals, but incubation with C. neoformans brought those levels back to baseline amounts. Future studies will compare these components in the media to those from incubations with anti-cryptococcal molecules.