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Genetic characterization of the regulatory elements of the biosynthesis and uptake of amino acids and their role in virulence of Cryptococcus neoformans

Grant number: 16/14542-8
Support type:Regular Research Grants
Duration: October 01, 2016 - June 30, 2019
Field of knowledge:Biological Sciences - Genetics
Principal Investigator:Renata Castiglioni Pascon
Grantee:Renata Castiglioni Pascon
Home Institution: Instituto de Ciências Ambientais, Químicas e Farmacêuticas (ICAQF). Universidade Federal de São Paulo (UNIFESP). Campus Diadema. Diadema , SP, Brazil

Abstract

C. neoformans is an opportunistic fungal pathogen of great medical importance because it affects immunocompromised individuals. Treatment against eukaryotic pathogens is difficult because there are few options of antifungal drugs and low selective toxicity. As a result, there is an effort of the scientific community to better understand the differences between pathogens and hosts in relation to the mechanisms that control essential biological processes, in order to find new useful drug targets. Studies on synthesis, uptake and recycling of amino acids have been shown to be very promising. Our previous studies have shown that the molecular mechanisms of biosynthesis and uptake of amino acids are (i) essential for virulence in C. neoformans, (ii) are very different from fungi and animals, as there is evidence of (iii) distinction of these processes among the ascomycetes and basidiomycetes. Still, our data showed that elements linked to the biosynthesis (enzymes) and amino acid uptake (permeases) are the targets of inhibitors of fungal growth. However, little is known about the regulation of this important nutritional process in C. neoformans and Basidiomycetes in general. In S. cerevisiae three regulatory pathways governing the acquisition of such nutrient: GAAC (Global Amino Acid Control), SPS-sensing and catabolic repression by the preferred source of nitrogen (NCR). In C. neoformans, NCR was reported by other laboratories and our published data demonstrate that it controls the genes related to the biosynthesis and uptake of amino acids. However, our experiments indicate that two other mechanisms (GAAC and SPS-sensing) can act in C. neoformans, though with different genetic elements. Further, recently we identified that uptake of amino acids is essential for the resistance to thermal and oxidative stress, conditions which are found in the host, and therefore are essential for virulence. The proposed work aims to explore the genetic basis that regulate the biosynthesis and uptake of amino acids using two approaches: (i) study the regulation based on the similar mechanisms known in ascomycetes (GAAC and SPS sensing) and (ii) explore the regulatory relationships between heat stress and amino acid uptake, a phenomenon detected by our study, and evaluate how all these regulatory processes affect the virulence of C. neoformans. We expect (i) to know the mechanisms governing the uptake of amino acids in C. neoformans and basidiomycetes and (ii) in this study reflect new targets for treatment options against Cryptococcus and other fungal diseases. (AU)

Scientific publications
(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)
DE MELO, AMANDA TEIXEIRA; MARTHO, KEVIN FELIPE; ROBERTO, THIAGO NUNES; NISHIDUKA, ERIKA S.; MACHADO JR, JOEL; BRUSTOLINI, OTAVIO J. B.; TASHIMA, ALEXANDRE K.; TEREZAVASCONCELOS, ANA; VALLIM, MARCELO A.; PASCON, RENATA C. The regulation of the sulfur amino acid biosynthetic pathway in Cryptococcus neoformans: the relationship of Cys3, Calcineurin, and Gpp2 phosphatases. SCIENTIFIC REPORTS, v. 9, AUG 15 2019. Web of Science Citations: 0.
CALVETE, CRISLAINE LAMBIASE; MARTHO, KEVIN FELIPE; FELIZARDO, GABRIELLE; PAES, ALEXANDRE; NUNES, JOAO MIGUEL; FERREIRA, CAMILA OLIVEIRA; VALLIM, MARCELO A.; PASCON, RENATA C. Amino acid permeases in Cryptococcus neoformans are required for high temperature growth and virulence; and are regulated by Ras signaling. PLoS One, v. 14, n. 1 JAN 25 2019. Web of Science Citations: 3.
GONTIJO, FABIANO DE ASSIS; DE MELO, AMANDA TEIXEIRA; PASCON, RENATA C.; FERNANDES, LARISSA; PAES, HUGO COSTA; ALSPAUGH, J. ANDREW; VALLIM, MARCELO A. The role of Aspartyl aminopeptidase (Ape4) in Cryptococcus neoformans virulence and authophagy. PLoS One, v. 12, n. 5 MAY 25 2017. Web of Science Citations: 3.

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