Estudo dos elementos regulatórios que controlam a captação de aminoácidos em Cryptococcus neoformans
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Data
2021-04-01
Autores
Martho, Kevin Felipe Cruz [UNIFESP]
Orientadores
Pascon
Pascon, Renata Castiglioni [UNIFESP]
Tipo
Tese de doutorado
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Resumo
A alta taxa de letalidade causada por fungos oportunistas como Cryptococcus neoformans está relacionada principalmente ao pequeno repertório de antifúngicos, à instabilidade das terapias fúngicas e ao constante surgimento de cepas resistentes. Portanto, novas terapias antifúngicas são necessárias. As vias de biossíntese e captação de aminoácidos têm sido exploradas para obtenção de novos alvos moleculares e demonstraram alto potencial, pois auxiliam na adaptação e colonização no hospedeiro, afetam a patogênese e, portanto, podem ser considerados bons alvos moleculares. Recentemente os elementos genéticos que regulam essas vias e como estes processos regulatórios afetam a virulência em C. neoformans começaram a ser estudados pelo nosso grupo. Entre os elementos estudados, foi identificado que a proteína sinalizadora Ras1 que governa o crescimento à 37°C em C. neoformans atua também na ativação da expressão das permeases de aminoácidos, sugerindo ser um importante elemento na regulação da captação de aminoácidos. Foi estudado também o fator de transcrição Cys3, que controla a captação de sulfato e a biossíntese de aminoácidos sulfurosos. A deleção deste gene compromete a disponibilidade destes aminoácidos e afeta a virulência de C. neoformans. Além disso, os dados indicam que Cys3 é regulado pelo complexo calcineurina e pela fosfatase Gpp2, a qual foi alvo de estudo deste trabalho. Em Saccharomyces cerevisiae, Gpp2 é uma fosfatase que atua na biossíntese do glicerol, uma importante molécula que exerce diversas funções no metabolismo e proteção contra diversos agentes estressores como alta concentração de sais e baixa temperatura. Neste trabalho foram estudados diversos aspectos do ciclo de vida, da virulência e da patogenicidade de C. neoformans em uma linhagem contendo uma deleção do gene GPP2. Os fenótipos encontrados sugerem que esta proteína é importante, não só para a biossíntese do glicerol, mas também para a adaptação geral aos vários estresses, virulência e pode ser um interessante alvo terapêutico. Ainda, os próximos passos deste trabalho poderá esclarecer quais são os alvos de interação e ativação de Gpp2. Dessa forma, isto irá possibilitar uma maior compreensão do papel desta fosfatase para processos fisiológicos que possibilitam a adaptação e sobrevivência de C. neoformans em seu hospedeiro humano. De modo geral, os conhecimentos obtidos neste trabalho sugerem que estes processos fisiológicos não são controlados por um único sistema, mas através de uma conexão entre diversas vias, gerando uma rede que garante o sucesso da adaptação do fungo frente as condições impostas pelo meio.
The high lethality rate caused by opportunistic fungi such as Cryptococcus neoformans is mainly related to the small repertoire of antifungals, the instability of fungal therapies and the constant emergence of resistant strains. Therefore, new antifungal therapies are necessary. The biosynthesis and amino acid uptake pathways have been explored to obtain new molecular targets and have demonstrated high potential, as they aid in adaptation and colonization in the host, affect pathogenesis and, therefore, can be considered good molecular targets. Recently the genetic elements that regulate these pathways and how these regulatory processes affect virulence in C. neoformans have begun to be studied by our group. Among the elements studied, it was identified that the signaling protein Ras1 that governs growth at 37°C in C. neoformans also acts in the activation of the expression of amino acid permeases, suggesting that it is an important element in the regulation of amino acid uptake. The transcription factor Cys3 was also studied, which controls sulfate uptake and biosynthesis of sulfurous amino acids. The addition of this gene compromises the availability of these amino acids and affects the virulence of C. neoformans. In addition, the data indicate that Cys3 is regulated by calcineurin complex and phosphatase Gpp2, which was the subject of this study. In Saccharomyces cerevisiae, Gpp2 is a phosphatase that acts in the biosynthesis of glycerol, an important molecule that performs several functions in metabolism and protection against various stressing agents such as high concentration of salts and low temperature. In this work, several aspects of the life cycle, virulence and pathogenicity of C. neoformans were studied in a lineage containing a dissection of the GPP2 gene. The phenotypes found suggest that this protein is important not only for glycerol biosynthesis, but also for general adaptation to various stresses, virulence and may be an interesting therapeutic target. Furthermore, the next steps of this work may clarify the targets of interaction and activation of Gpp2. Thus, this will allow a greater understanding of the role of this phosphatase for physiological processes that enable the adaptation and survival of C. neoformans in its human host. In general, the knowledge obtained in this work suggests that these physiological processes are not controlled by a single system, but through a connection between several pathways, generating a network that guarantees the success of the adaptation of the fungus against the conditions imposed by the environment.
The high lethality rate caused by opportunistic fungi such as Cryptococcus neoformans is mainly related to the small repertoire of antifungals, the instability of fungal therapies and the constant emergence of resistant strains. Therefore, new antifungal therapies are necessary. The biosynthesis and amino acid uptake pathways have been explored to obtain new molecular targets and have demonstrated high potential, as they aid in adaptation and colonization in the host, affect pathogenesis and, therefore, can be considered good molecular targets. Recently the genetic elements that regulate these pathways and how these regulatory processes affect virulence in C. neoformans have begun to be studied by our group. Among the elements studied, it was identified that the signaling protein Ras1 that governs growth at 37°C in C. neoformans also acts in the activation of the expression of amino acid permeases, suggesting that it is an important element in the regulation of amino acid uptake. The transcription factor Cys3 was also studied, which controls sulfate uptake and biosynthesis of sulfurous amino acids. The addition of this gene compromises the availability of these amino acids and affects the virulence of C. neoformans. In addition, the data indicate that Cys3 is regulated by calcineurin complex and phosphatase Gpp2, which was the subject of this study. In Saccharomyces cerevisiae, Gpp2 is a phosphatase that acts in the biosynthesis of glycerol, an important molecule that performs several functions in metabolism and protection against various stressing agents such as high concentration of salts and low temperature. In this work, several aspects of the life cycle, virulence and pathogenicity of C. neoformans were studied in a lineage containing a dissection of the GPP2 gene. The phenotypes found suggest that this protein is important not only for glycerol biosynthesis, but also for general adaptation to various stresses, virulence and may be an interesting therapeutic target. Furthermore, the next steps of this work may clarify the targets of interaction and activation of Gpp2. Thus, this will allow a greater understanding of the role of this phosphatase for physiological processes that enable the adaptation and survival of C. neoformans in its human host. In general, the knowledge obtained in this work suggests that these physiological processes are not controlled by a single system, but through a connection between several pathways, generating a network that guarantees the success of the adaptation of the fungus against the conditions imposed by the environment.
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Citação
Martho, Kevin Felipe Cruz. Estudo dos elementos regulatórios que controlam a captação de aminoácidos em Cryptococcus neoformans. 2021. 64 f. Tese (doutorado) – Instituto de Ciência e Tecnologia, Universidade Federal de São Paulo (UNIFESP), São José dos Campos, 2021.