Estudo da utilização de heme por Paracoccidioides lutzii: análise do proteoma de parede celular após exposição à hemoglobina e expressão heteróloga de Pga7, um provável receptor de hemoglobina

• Autor(a) principal: Souza, Aparecido Ferreira de
• Data de Publicação: 2017
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Biblioteca Digital de Teses e Dissertações da UFG
• Texto Completo: http://repositorio.bc.ufg.br/tede/handle/tede/6911
• topic: Paracoccidioidomicose; Ferro; NanoUPLC-MSE; Adesinas; Interações patógeno-hospedeiro; Paracoccidioidomycosis; Iron; NanoUPLC-MSE; Adhesins; Host-pathogen interactions; CIENCIAS BIOLOGICAS::GENETICA

Iron (Fe) is an indispensable metal for most biological systems and is a target of competition in host-pathogen interactions. In humans, most Fe is complexed to the cofactor heme, present in hemoglobin, a molecule that is exploited by pathogens as an iron source. Paracoccidioides spp., a complex of thermodymorphic pathogenic fungi, are the etiological agents of paracoccidioidomycosis (PCM), a systemic mycosis endemic in Latin America. Paracoccidioides spp. are able to use hemoglobin in a receptor(PbRbt5)-mediated process. However experimental evidence points to the existence of a complex system with the presence of other proteins. In the present work, we demonstrated the similarity between PAAG_02225 (PbPga7), from Paracoccidioides lutzii, and the sequence of the heme/hemoglobin receptor Pga7 from Candida albicans, and expressed PbPga7 in Escherichia coli. Due to the presence of rare codons in P. lutzii sequence, compared to the codons preferably used by Escherichia coli, chemical synthesis of the gene was employed. The expression of PbPga7 protein opens perspectives for PbPga7 characterization. In addition, nanoUPLC-MSE was employed to analyze P. lutzii cell wall proteome. We observed that the treatment of fungus with hemoglobin promotes induction of potential adhesins and defense-related enzymes against reactive oxygen species. These data indicate that these proteins may be important for the pathogen to access hemoglobin by adhering and lysing erythrocytes, besides counteracting the toxicity generated by heme/hemoglobin released from erythrocytes, allowing the uptake and use of these molecules. The results obtained in the present work reinforce the complexity of the interaction event between pathogen and host and, in addition, contribute to broaden the understanding of the biology of Paracoccidioides spp.