HDAC genes play distinct and redundant roles in Cryptococcus neoformans virulence

Fabiana Brandão,J Andrew Alspaugh,Kaila Pianalto,Kyla S Ost,Connie B Nichols,Shannon K Esher,Anamélia L Bocca,Marcio José Poças-Fonseca,Larissa Fernandes

doi:10.1038/s41598-018-21965-y

Fabiana Brandão, J Andrew Alspaugh + Show 7 more

Open Access

https://doi.org/10.1038/s41598-018-21965-y

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Journal: Scientific Reports	Publication Date: Mar 26, 2018
Citations: 45	License type: open-access

Affiliation: Universidade de Brasília, Duke University

Abstract

The human fungal pathogen Cryptococcus neoformans undergoes many phenotypic changes to promote its survival in specific ecological niches and inside the host. To explore the role of chromatin remodeling on the expression of virulence-related traits, we identified and deleted seven genes encoding predicted class I/II histone deacetylases (HDACs) in the C. neoformans genome. These studies demonstrated that individual HDACs control non-identical but overlapping cellular processes associated with virulence, including thermotolerance, capsule formation, melanin synthesis, protease activity and cell wall integrity. We also determined the HDAC genes necessary for C. neoformans survival during in vitro macrophage infection and in animal models of cryptococcosis. Our results identified the HDA1 HDAC gene as a central mediator controlling several cellular processes, including mating and virulence. Finally, a global gene expression profile comparing the hda1Δ mutant versus wild-type revealed altered transcription of specific genes associated with the most prominent virulence attributes in this fungal pathogen. This study directly correlates the effects of Class I/II HDAC-mediated chromatin remodeling on the marked phenotypic plasticity and virulence potential of this microorganism. Furthermore, our results provide insights into regulatory mechanisms involved in virulence gene expression that are likely shared with other microbial pathogens.

Highlights

Pathogenic microorganisms must maintain the ability to adapt to environmental changes as well as to the specific cell stresses encountered during interaction with host cells
The other five predicted histone deacetylases (HDACs) genes were named according to their closest relative in S. cerevisiae or S. pombe: Class I: HOS1 (CNAG_05096), CLR61 (CLR6 homologue-1; CNAG_01699), and CLR62 (CLR6 homologue-2; CNAG_05276); Class II: HDA1/CLR3 (CNAG_01563), and HOS3 (CNAG_00660)
In our RNA-Seq analyses we found that the same group of genes displayed increased levels of mRNA in the hda1Δ mutant (Table 2), reinforcing the concept that fungal Hda[1] orthologs play a role in the assembly of subtelomeric heterochromatin in fungi as diverse as the basidiomycete C. neoformans and the ascomycete S. pombe[22,50]

Summary

Introduction

Pathogenic microorganisms must maintain the ability to adapt to environmental changes as well as to the specific cell stresses encountered during interaction with host cells. HDACs catalyze the removal of acetyl groups, leading to chromatin condensation[13,14] These enzymes play crucial roles in regulating gene expression as they modulate the accessibility of chromatin to transcriptional regulators and other regulating factors[14]. HDACs are evolutionarily conserved and are found in plants, fungi, and animals, as well as archaea and eubacteria[15,16] They have been associated with epigenetic phenotypic changes in many fungal species such as Ustilago maydis[17], Aspergillus nidulans[18], Candida albicans[19,20,21], Schizosaccharomyces pombe[22,23], Saccharomyces cerevisiae[24], and Cryptococcus neoformans[25,26]. In the fission yeast S. pombe there are two class I HDACs (Clr[6] and Hos2) and one class II HDAC (Hda1)[6,27]

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