Characterization of the Paracoccidioides Hypoxia Response Reveals New Insights into Pathogenesis Mechanisms of This Important Human Pathogenic Fungus

Abstract

BackgroundHypoxic microenvironments are generated during fungal infection. It has been described that to survive in the human host, fungi must also tolerate and overcome in vivo microenvironmental stress conditions including low oxygen tension; however nothing is known how Paracoccidioides species respond to hypoxia. The genus Paracoccidioides comprises human thermal dimorphic fungi and are causative agents of paracoccidioidomycosis (PCM), an important mycosis in Latin America.Methodology/Principal FindingsIn this work, a detailed hypoxia characterization was performed in Paracoccidioides. Using NanoUPLC-MSE proteomic approach, we obtained a total of 288 proteins differentially regulated in 12 and 24 h of hypoxia, providing a global view of metabolic changes during this stress. In addition, a functional characterization of the homologue to the most important molecule involved in hypoxia responses in other fungi, the SREBP (sterol regulatory element binding protein) was performed. We observed that Paracoccidioides species have a functional homologue of SREBP, named here as SrbA, detected by using a heterologous genetic approach in the srbA null mutant in Aspergillus fumigatus. Paracoccidioides srbA (PbsrbA), in addition to involvement in hypoxia, is probable involved in iron adaptation and azole drug resistance responses.Conclusions/SignificanceIn this study, the hypoxia was characterized in Paracoccidioides. The first results can be important for a better understanding of the fungal adaptation to the host and improve the arsenal of molecules for the development of alternative treatment options in future, since molecules related to fungal adaptation to low oxygen levels are important to virulence and pathogenesis in human pathogenic fungi.

ParacoccidioidesSpp.: Virulence Factors and Immune-Evasion Strategies

“…An evaluation of mitochondrial activity showed a lower activity at the first 12 hours under hypoxia, and restoration of activity at 24 hours, in agreement with the proteomic results, showing the potential for adaptation of this fungus under low oxygen levels [162]. The same work revealed that P. lutzii contains homologs of SrbA, a sterol regulatory element binding protein (SREBP) and key regulator of hypoxia adaptation in fungi [162]. Functional complementation of an Aspergillus fumigatus srbA null mutant by the Paracoccidioides srbA ( PbsrbA ) gene restored the null mutant hyphal growth under hypoxia, which suggests that PbsrbA may promote adaptation to hypoxic microenvironments.…”

Sensitisation of an Azole-Resistant Aspergillus fumigatus Strain containing the Cyp51A-Related Mutation by Deleting the SrbA Gene

“…Yeasts Saccharomyces cerevisiae and Candida albicans have no apparent SREBP orthologues, whereas Schizosaccharomyces pombe and Cryptococcus neoformans contain functional SREBPs that regulate ergosterol biosynthesis and aid in adaptation to hypoxic conditions293031. Amongst the filamentous fungi, SrbA from A. fumigatus is the only characterised SREBP, except for SrbA from Paracoccidioides , the coding sequence of which was shown to function heterologously in A. fumigatus cells32. Bioinformatic analysis suggests that important plant pathogen species Fusarium and Magnaporthe may contain SREBPs, although the physiological functions of these proteins are yet to be investigated.…”

Analysis ofParacoccidioideslutziimitochondria: a proteomic approach

“…The proteomic approach was performed using NanoUPLC‐MS E as previously described (Murad and Rech, ; Murad et al, ) and adapted for samples of Paracoccidioides species in our laboratory (Bailão et al, ; Lima et al, , ; Oliveira et al, ). The peptide and protein data were generated by the PLGS process and data from analysis are shown in Figure S6.…”