Hemoglobin uptake by Paracoccidioides spp. is receptor-mediated.
Iron is essential for the proliferation of fungal pathogens during infection. The availability of iron is limited due to its association with host proteins. Fungal pathogens have evolved different mechanisms to acquire iron from host; however, little is known regarding how Paracoccidioides species incorporate and metabolize this ion. In this work, host iron sources that are used by Paracoccidioides spp. were investigated. Robust fungal growth in the presence of the iron-containing molecules hemin and hemoglobin was observed. Paracoccidioides spp. present hemolytic activity and have the ability to internalize a protoporphyrin ring. Using real-time PCR and nanoUPLC-MSE proteomic approaches, fungal growth in the presence of hemoglobin was shown to result in the positive regulation of transcripts that encode putative hemoglobin receptors, in addition to the induction of proteins that are required for amino acid metabolism and vacuolar protein degradation. In fact, one hemoglobin receptor ortholog, Rbt5, was identified as a surface GPI-anchored protein that recognized hemin, protoporphyrin and hemoglobin in vitro. Antisense RNA technology and Agrobacterium tumefaciens-mediated transformation were used to generate mitotically stable Pbrbt5 mutants. The knockdown strain had a lower survival inside macrophages and in mouse spleen when compared with the parental strain, which suggested that Rbt5 could act as a virulence factor. In summary, our data indicate that Paracoccidioides spp. can use hemoglobin as an iron source most likely through receptor-mediated pathways that might be relevant for pathogenic mechanisms.
Laboratório de Biologia Molecular, Instituto de Ciências Biológicas, Universidade Federal de Goiás, Goiânia, Goiás, Brazil; Unidade Universitária de Iporá, Universidade Estadual de Goiás, Iporá, Goiás, Brazil; Programa de Pós Graduação em Patologia Molecular, Faculdade de Medicina, Universidade de Brasília, Brasília, Distrito Federal, Brazil.
Elisa Flávia Luiz Cardoso
EF
Bailão
Laboratório de Biologia Molecular, Instituto de Ciências Biológicas, Universidade Federal de Goiás, Goiânia, Goiás, Brazil.
Juliana Alves
JA
Parente
Laboratório de Biologia Molecular, Instituto de Ciências Biológicas, Universidade Federal de Goiás, Goiânia, Goiás, Brazil.
Laurine Lacerda
LL
Pigosso
Laboratório de Biologia Molecular, Instituto de Ciências Biológicas, Universidade Federal de Goiás, Goiânia, Goiás, Brazil.
Kelly Pacheco
KP
de Castro
Instituto de Microbiologia Professor Paulo de Góes, Universidade Federal do Rio de Janeiro, Brazil.
Fernanda Lopes
FL
Fonseca
Laboratório de Biologia Molecular, Instituto de Ciências Biológicas, Universidade Federal de Goiás, Goiânia, Goiás, Brazil; Programa de Pós Graduação em Patologia Molecular, Faculdade de Medicina, Universidade de Brasília, Brasília, Distrito Federal, Brazil.
Mirelle Garcia
MG
Silva-Bailão
Laboratório de Microscopia Eletrônica, Universidade de Brasília, Distrito Federal, Brazil.
Sônia Nair
SN
Báo
Laboratório de Biologia Molecular, Instituto de Ciências Biológicas, Universidade Federal de Goiás, Goiânia, Goiás, Brazil.
Alexandre Melo
AM
Bailão
Instituto de Microbiologia Professor Paulo de Góes, Universidade Federal do Rio de Janeiro, Brazil; Fundação Oswaldo Cruz - Fiocruz, Centro de Desenvolvimento Tecnológico em Saúde (CDTS), Rio de Janeiro, Brazil.
Marcio L
ML
Rodrigues
Unidad de Biología Celular y Molecular, Corporación para Investigaciones Biológicas (CIB), Medellín, Colombia; Facultad de Ciencias de la Salud, Institución Universitaria Colegio Mayor de Antioquia, Medellín, Colombia.
Orville
O
Hernandez
Unidad de Biología Celular y Molecular, Corporación para Investigaciones Biológicas (CIB), Medellín, Colombia; Facultad de Medicina, Universidad de Antioquia, Medellín, Colombia.
Juan G
JG
McEwen
Laboratório de Biologia Molecular, Instituto de Ciências Biológicas, Universidade Federal de Goiás, Goiânia, Goiás, Brazil.
Célia Maria de Almeida
CM
Soares
D000818:Animals; D002460:Cell Line; D004912:Erythrocytes; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism*; D006418:Heme / Q000378:metabolism; D006454:Hemoglobins / Q000378:metabolism*; D006461:Hemolysis; D007501:Iron / Q000378:metabolism; D033862:Iron-Binding Proteins / Q000378:metabolism; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D010228:Paracoccidioides / Q000254:growth & development / Q000378:metabolism*; D011956:Receptors, Cell Surface / Q000235:genetics / Q000378:metabolism*; D012756:Sheep
D005656:Fungal Proteins; D006454:Hemoglobins; D033862:Iron-Binding Proteins; D011956:Receptors, Cell Surface; D006418:Heme; D007501:Iron