Interacting with hemoglobin: Paracoccidioides spp. recruits hsp30 on its cell surface for enhanced ability to use this iron source

Paracoccidioides spp. are thermally dimorphic fungi that cause paracoccidioidomycosis and can affect both immunocompetent and immunocompromised individuals. The infection can lead to moderate or severe illness and death. Paracoccidioides spp. undergo micronutrients deprivation within the host, including iron. To overcome such cellular stress, this genus of fungi responds in multiple ways, such as the utilization of hemoglobin. A glycosylphosphatidylinositol (GPI)-anchored fungal receptor, Rbt5, has the primary role of acquiring the essential nutrient iron from hemoglobin. Conversely, it is not clear if additional proteins participate in the process of using hemoglobin by the fungus. Therefore, in order to investigate changes in the proteomic level of P. lutzii cell wall, we deprived the fungus of iron and then treated those cells with hemoglobin. Deprived iron cells were used as control. Next, we performed cell wall fractionation and the obtained proteins were submitted to nanoUPLC-MSE. Protein expression levels of the cell wall F1 fraction of cells exposed to hemoglobin were compared with the protein expression of the cell wall F1 fraction of iron-deprived cells. Our results showed that P. lutzii exposure to hemoglobin increased the level of adhesins expression by the fungus, according to the proteomic data. We confirmed that the exposure of the fungus to hemoglobin increased its ability to adhere to macrophages by flow cytometry. In addition, we found that HSP30 of P. lutzii is a novel hemoglobin-binding protein and a possible heme oxygenase. In order to investigate the importance of HSP30 in the Paracoccidioides genus, we developed a Paracoccidioides brasiliensis knockdown strain of HSP30 via Agrobacterium tumefaciens-mediated transformation and demonstrated that silencing this gene decreases the ability of P. brasiliensis to use hemoglobin as a nutrient source. Additional studies are needed to establish HSP30 as a virulence factor, which can support the development of new therapeutic and/or diagnostic approaches.We thank CAPES: CNPq and FAPEG for providing fellowships to A.F.d.S, M.V.T., K.S.F.eS., J.S.d.C, C.A.P., L.C.B., J.D.P. and R.A.G., F.R. was supported by the Northern Portugal Regional Operational Programme (NORTE 2020), under the Portugal 2020 Partnership Agreement, through the European Regional Development Fund (FEDER) (NORTE-01-0145-FEDER-000013). C.M.d.A.S. and M.P. belong to the Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq). This work was supported by grants from Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) and Fundação de Amparo à Pesquisa do Estado de Goiás (FAPEG), Instituto Nacional de Ciência e Tecnologia (INCT) de Estratégias de Interação Patógeno-Hospedeiro (grant number 201810267000022/INCT-FAPEG)

Characterization of carbonic anhydrases of Paracoccidioides brasiliensis

Submitted by Luciana Ferreira ([email protected]) on 2015-05-18T13:43:16Z No. of bitstreams: 2 Dissertação - Mariana Vieira Tomazett - 2011.pdf: 1259531 bytes, checksum: aa04f3f36448deb32394c0d322cbc8b7 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5)Approved for entry into archive by Luciana Ferreira ([email protected]) on 2015-05-18T13:48:25Z (GMT) No. of bitstreams: 2 Dissertação - Mariana Vieira Tomazett - 2011.pdf: 1259531 bytes, checksum: aa04f3f36448deb32394c0d322cbc8b7 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5)Made available in DSpace on 2015-05-18T13:48:26Z (GMT). No. of bitstreams: 2 Dissertação - Mariana Vieira Tomazett - 2011.pdf: 1259531 bytes, checksum: aa04f3f36448deb32394c0d322cbc8b7 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Previous issue date: 2011-08-29Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPqParacoccidioidomycosis (PCM) is the most important endemic deep mycosis in Latin America. Understanding of the complex interactions between the fungus and host must include the identification of gene expression patterns during infection. Carbonic anhydrase (CA) belongs to the family of zinc metalloenzymes that catalyzes the reversible hydratation of carbon dioxide to bicarbonate. Transcriptional studies have shown that carbonic anhydrase of P. brasiliensis is expressed in yeast cells recovered from liver of infected mice. In the present work, we characterized the cDNAs encoding for four carbonic anhydrases of P.brasiliensis (PbCA1, PbCA2, PbCA3, PbCA4). Recombinant PbCA1, 3 and 4 were obtained in heterologous systems with 33 kDa, 28 kDa and 32 kDa respectively. Mass spectrometry analysis confirmed the sequences of the produced proteins. The expression of PbCAs transcripts was evaluated by using real-time RT-PCR in mycelium, yeast cells and mycelium to yeast transition, in yeast cells exposed to CO2 and yeast cells recovery directly from liver and spleen. In the presence of CO2, PbCA1, PbCA2 and PbCA4 gene expression was reduced in the course of time. PbCA1 transcript expression was induced during the mycelium to yeast transition. PbCA2 and PbCA4 gene expression was higher in yeast cells, when compared to mycelium and mycelium to yeast transition. Pbca1 was induced yeast cells recovery directly from liver and spleen while the transcripts for Pbca2 and Pbca4 were repressed in all condictions. The gene expression data suggest differential roles of the CAs in the fungal physiology.Paracoccidioidomicose (PCM) é a mais importante micose endêmica na América Latina. A compreensão das interações complexas entre o fungo e o hospedeiro deve incluir a identificação de padrões de expressão gênica durante a infecção. Anidrase carbônica (CA) pertence à família de metaloenzimas de zinco que catalisa a hidratação reversível do dióxido de carbono para bicarbonato. Estudos transcricionais têm mostrado que uma anidrase carbônica de P. brasiliensis é expressa em células de levedura recuperadas de fígado de camundongos infectados. No presente trabalho, nós caracterizamos os cDNAs que codificam para quatro anidrases carbônicas de P.brasiliensis (PbCA1, PbCA2, PbCA3, PbCA4). As recombinante de PbCA1, PbCA3 e PbCA4 foram obtidas em sistemas heterólogos com 33 kDa, 28 kDa e 32 kDa, respectivamente. Análise por espectrometria de massas confirmou as seqüências das proteínas produzidas. A expressão dos transcritos de Pbcas foi avaliada usando real-time RT-PCR em micélio, levedura e transição de micélio para levedura; em células de levedura expostas a CO2 e células de leveduras recuperadas diretamente do fígado e baço. Na presença de CO2, a expressão dos genes de Pbca1, Pbca2 e Pbca4 foi reduzida no decorrer do tempo. A expressão do transcrito de Pbca1 foi induzida durante a transição de micélio para levedura. A expressão de Pbca2 e Pbca4 foi maior em células de levedura, quando comparada com micélio e transição de micélio para levedura.O transcrito para Pbca1 foi induzido em células de leveduras recuperadas diretamente do fígado e baço, enquanto que os transcritos para Pbca2 e Pbca4 foram reprimidos em todas as conduções. Os dados de expressão gênica sugerem diferentes papéis das CAs na fisiologia dos fungos

Molecular and biochemical characterization of carbonic anhydrases of Paracoccidioides

Abstract Carbonic anhydrases (CA) belong to the family of zinc metalloenzymes that catalyze the reversible hydration of carbon dioxide to bicarbonate. In the present work, we characterized the cDNAs of four Paracoccidioides CAs (CA1, CA2, CA3, and CA4). In the presence of CO2, there was not a significant increase in fungal ca1, ca2 and ca4 gene expression. The ca1 transcript was induced during the mycelium-to-yeast transition, while ca2 and ca4 gene expression was much higher in yeast cells, when compared to mycelium and mycelium-to-yeast transition. The ca1 transcript was induced in yeast cells recovered directly from liver and spleen of infected mice, while transcripts for ca2 and ca4 were down-regulated. Recombinant CA1 (rCA1) and CA4 (rCA4), with 33 kDa and 32 kDa respectively, were obtained from bacteria. The enzymes rCA1 (β-class) and rCA4 (α-class) were characterized regarding pH, temperature, ions and amino acids addition influence. Both enzymes were stable at pHs 7.5-8.5 and temperatures of 30-35 °C. The enzymes were dramatically inhibited by Hg+2 and activated by Zn+2, while only rCA4 was stimulated by Fe2+. Among the amino acids tested (all in L configuration), arginine, lysine, tryptophan and histidine enhanced residual activity of rCA1 and rCA4

Paracoccidioides lutzii Formamidase Contributes to Fungal Survival in Macrophages

Nitrogen is a crucial nutrient for microorganisms that compose essential biomolecules. However, hosts limit this nutrient as a strategy to counter infections, therefore, pathogens use adaptive mechanisms to uptake nitrogen from alternative sources. In fungi, nitrogen catabolite repression (NCR) activates transcription factors to acquire nitrogen from alternative sources when preferential sources are absent. Formamidase has been related to nitrogen depletion in Aspergillus nidulans through formamide degradation to use the released ammonia as a nitrogen source. In Paracoccidioides spp., formamidase is highly expressed in transcriptomic and proteomic analyses. Here, we aim to investigate the importance of formamidase to Paracoccidioides lutzii. Thereby, we developed a P. lutzii silenced strain of fmd gene (AsFmd) by antisense RNA technology using Agrobacterium tumefaciens-mediated transformation (ATMT). The AsFmd strain led to increased urease expression, an enzyme related to nitrogen assimilation in other fungi, suggesting that P. lutzii might explore urease as an alternative route for ammonia metabolism as a nitrogen source. Moreover, formamidase was important for fungal survival inside macrophages, as fungal recovery after macrophage infection was lower in AsFmd compared to wild-type (WT) strain. Our findings suggest potential alternatives of nitrogen acquisition regulation in P. lutzii, evidencing formamidase influence in fungal virulence