Ferroptosis in Cryptococcus neoformans: molecular, cellular and microbiological approaches

• Grant number: 24/01658-4
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• Start date: September 01, 2024
• End date: August 31, 2026
• Field of knowledge: Biological Sciences - Microbiology - Biology and Physiology of Microorganisms
• Principal Investigator: Kelly Ishida
• Grantee: Daniel Felipe Freitas de Jesus
• Host Institution: Instituto de Ciências Biomédicas (ICB). Universidade de São Paulo (USP). São Paulo , SP, Brazil

Abstract

Cryptococcus is the etiological agent of cryptococcosis, and it is estimated that there are 180,000 deaths and more than 270,000 annual cases of the disease worldwide, a fact associated with the immunosuppression of patients, the virulence factors of the fungus and the limited arsenal of antifungals to treat cryptococcosis. It is known that autophagy, apoptosis, and necrosis can occur physiologically or through the action of antifungal agents. On the other hand, iron-dependent cell death is little studied in fungi and has been described as an essential mechanism in the morphogenesis and virulence of the phytopathogen Magnaporthe oryzae and has been related to cardiac, neurodegenerative pathologies and cancers. Currently, ferroptosis has not been described in fungi of clinical importance and the present study seeks to highlight this mechanism in Cryptococcus neoformans and expand knowledge of fungal cell biology with new therapeutic perspectives in the treatment of cryptococcosis. Using molecular, cellular and microbiological approaches, we intend to investigate the existence of the mechanism of death by ferroptosis, as well as it role in the pathogenesis of C. neoformans. Our in silico analyzes demonstrated the presence in C. neoformans of hypothetical genes of the ferroptosis pathway (XC transporter--like, YGSC-like, GPX4-like, ACLS1-like, ACLS2-like, LPCAT3-like), whose hypothetical proteins were predicted to have the same cellular location as the proteins described in the literature. The hypothetical proteins present high coverage (57-97%), similarity (45-57%) and identity (28%-40%) in relation to proteins described in the literature. C. neoformans yeasts showed growth in medium with Fe2+ and Fe3+, however, in the first hours of cultivation, Fe3+ was more toxic to yeasts than Fe2+, in addition, the presence of the iron chelator reduced the toxicity of Fe3+ to yeasts. These preliminary results demonstrate the existence of ferroptosis genes in C. neoformans and that the death of yeasts were iron dependent.