Project description:Candida spp. represent the third most frequent worldwide cause of infection in Intensive Care Units (ICUs) with a mortality rate of almost 40%. The classes of antifungals currently available include azoles, polyenes, echinocandins, pyrimidine derivatives, and allylamines. However, the therapeutical options for the treatment of candidiasis are drastically reduced by the increasing antifungal resistance. The growing need of a more targeted antifungal therapy is limited by the concern of finding molecules that specifically recognize the microbial cell without damaging the host. Epigenetic writers and erasers have emerged as promising targets in different contexts, including the treatment of fungal infections. In C. albicans, Hst3p, a sirtuin that deacetylates histone H3K56ac, represents an attractive antifungal target as it is essential for the fungus viability and virulence. Although the relevance of such epigenetic regulator is documented for the development of new antifungal therapies, the molecular mechanism behind Hst3p-mediated epigenetic regulation remains unrevealed. Here, we provide the first genome-wide profiling of H3K56ac in C. albicans; H3K56ac enriched regions are associated with Candida sp. pathogenicity. Upon Hst3p inhibition, 447 regions gain H3K56ac. Importantly, these genomic areas contain genes encoding for adhesin proteins, degradative enzymes, and white-opaque switch. Moreover, our RNA-seq analysis revealed 1330 upregulated and 1081 downregulated transcripts upon Hst3p inhibition, and among them, 87 genes whose transcription upregulation correlates well with changes in promoter H3K56 acetylation, including some well-known regulators of phenotypic switching and virulence, confirming that Hst3p is an appealing target for the development of new potential antifungal target.
Project description:Aneuploidy and the evolution of aneuploid karyotypes of Candida albicans strains was identified using aCGH. Whole chromosome and segmental aneuploidies, (specifically on the left arm of chromosome 5 - shown to be due to isochromosome formation) are associated with the appearance of resistance to the antifungal drug fluconazole. Keywords: Comparative Genomic Hybridization
Project description:Azoles are commonly used for the treatment of fungal infections and the ability of human fungal pathogens to rapidly respond to azole treatment is critical for the development of antifungal resistance. While the role of genetic mutations, chromosomal rearrangements and transcriptional mechanisms in azole resistance has been well-characterized, very little is known about post-transcriptional and translation mechanisms that drive this process. In addition, most previous genome-wide studies have focused on transcriptional responses to azole treatment, and likely serve as an inaccurate proxies due to extensive post-transcriptional and translational regulation. In this study we use ribosome profiling to provide the first picture of the global translational response of a major human fungal pathogen, Candida albicans, to treatment with fluconazole, one of the most widely used azole drugs. We identify sets of genes showing significantly altered translational efficiency (TE), including genes associated with a variety of biological processes such as the cell cycle, DNA repair, cell wall/cell membrane biosynthesis, transport, signaling, DNA- and RNA-binding activities and protein synthesis. Importantly, while there are similarities and differences among gene categories that are regulated by fluconazole at the translational vs. transcriptional levels, we observe very little overlap among individual genes controlled by these mechanisms. Our findings suggest that C. albicans possesses distinct translational mechanisms that are important for the response to antifungal treatment, which could eventually be targeted by novel antifungal therapies.