Transcriptome analysis of Sch9-depedent thermotolerance mechanism reveals a dual functional heat shock transcription factor, Hsf1, in Cryptococcus neoformans
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ABSTRACT:
ORGANISM(S): Cryptococcus neoformans var. neoformans JEC21 Cryptococcus neoformans var. grubii
PROVIDER: GSE66510 | GEO | 2015/06/01
SECONDARY ACCESSION(S): PRJNA277178
REPOSITORIES: GEO
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Project description:Thermotolerance is a crucial virulence attribute for Cryptococcus neoformans, which causes fatal fungal meningitis in humans. A protein kinase, Sch9, suppresses the thermotolerance of C. neoformans but its regulatory mechanism remains unknown. Here we elucidated the Sch9-dependent and -independent signaling networks for modulating the thermotolerance of C. neoformans through a genome-wide transcriptome analysis and reverse genetics approaches. We found that more than 1,800 genes were under transcriptional control during temperature upshift. Genes encoding for molecular chaperones and heat shock proteins were mainly upregulated, while those for translation, transcription, and sterol biosynthesis were highly suppressed. In this process Sch9 was found to regulate basal or induced expression levels of some temperature-responsive genes. Interestingly we found that Sch9 was involved in transcriptional regulation of the Ire1 kinase, which is a key sensor for the unfolded protein response pathway, and was found to be involved in ER stress response. Most notably, our data demonstrated that expression of HSF1, encoding a heat shock transcription factor 1, was downregulated during temperature upshift and Sch9 suppresses its downregulation. In spite of such expression patterns, Hsf1 was essential for growth and its overexpression indeed promoted the thermotolerance of C. neoformans, suggesting dual roles of Hsf1 in thermotolerance. This idea was supported by additional transcriptome analysis with HSF1 overexpression strain, which revealed that Hsf1 served as both activator and repressor. Hsf1 promoted genes such as Hsp104 and Hsp70 (Ssa1 and Ssa2), both of which were found to be highly upregulated during temperature upshift and required for thermotolerance, while Hsf1 repressed genes involved in oxidative stress and thermotolerance.
2015-06-01 | GSE66509 | GEO
Project description:Thermotolerance is a crucial virulence attribute for Cryptococcus neoformans, which causes fatal fungal meningitis in humans. A protein kinase, Sch9, suppresses the thermotolerance of C. neoformans but its regulatory mechanism remains unknown. Here we elucidated the Sch9-dependent and -independent signaling networks for modulating the thermotolerance of C. neoformans through a genome-wide transcriptome analysis and reverse genetics approaches. We found that more than 1,800 genes were under transcriptional control during temperature upshift. Genes encoding for molecular chaperones and heat shock proteins were mainly upregulated, while those for translation, transcription, and sterol biosynthesis were highly suppressed. In this process Sch9 was found to regulate basal or induced expression levels of some temperature-responsive genes. Interestingly we found that Sch9 was involved in transcriptional regulation of the Ire1 kinase, which is a key sensor for the unfolded protein response pathway, and was found to be involved in ER stress response. Most notably, our data demonstrated that expression of HSF1, encoding a heat shock transcription factor 1, was downregulated during temperature upshift and Sch9 suppresses its downregulation. In spite of such expression patterns, Hsf1 was essential for growth and its overexpression indeed promoted the thermotolerance of C. neoformans, suggesting dual roles of Hsf1 in thermotolerance. This idea was supported by additional transcriptome analysis with HSF1 overexpression strain, which revealed that Hsf1 served as both activator and repressor. Hsf1 promoted genes such as Hsp104 and Hsp70 (Ssa1 and Ssa2), both of which were found to be highly upregulated during temperature upshift and required for thermotolerance, while Hsf1 repressed genes involved in oxidative stress and thermotolerance.
2015-06-01 | GSE66508 | GEO
Project description:Transcriptome analysis of Sch9-depedent thermotolerance mechanism reveals a dual functional heat shock transcription factor, Hsf1, in Cryptococcus neoformans
| PRJNA277178 | ENA
Project description:Thermotolerance, a key factor essential for the virulence of pathogenic fungi including Cryptococcus neoformans, remains largely unexplored in terms of its underlying mechanism. In this study, our findings demonstrate that Set3C, a widely distributed and conserved histone deacetylase complex, is required for thermotolerance in Cryptococcus neoformans. Specifically, the deletion of the core subunit Set302, responsible for the integrity of the complex, results in a significant reduction in the growth ability under high stress and the viability at extreme temperature. Moreover, the absence of Set302 leads to a decrease in the production of capsule and melanin. Transcriptomics analysis revealed that Set302 regulates a large number of genes compared to normal condition, and their expression is responsive to heat stress. Notably, we observed that Set302 positively influences the expression of genes related to ubiquitin-proteasome system (UPS) at high temperature. Using GFP-α-synuclein overexpression model, we observed a pronounced accumulation of misfolded proteins under heat stress, consequently inhibiting the thermotolerance of Cryptococcus neoformans. Furthermore, the loss of Set302 exacerbates this inhibition of thermotolerance. Interestingly, set302∆ strain exhibits a similar phenotype under proteasome stress as it does under high temperature. We also found that set302∆ strain displayed significantly reduced pathogenicity and colonization ability compared to the wild-type strain in the murine infection model. Collectively, our findings indicate that Set302 modulates the degradation of misfolded proteins through the UPS pathway, thereby affecting the thermotolerance and pathogenicity of Cryptococcus neoformans.
2023-09-05 | GSE242109 | GEO
Project description:The heat shock response is a universal homeostatic cell autonomous reaction of organisms to cope with adverse environmental conditions. In mammalian cells, this response is mediated by the heat shock transcription factor Hsf1, which is monomeric in unstressed cells and upon activation trimerizes, and binds to promoters of heat shock genes. To understand the basic principle of Hsf1 activation we analyzed temperature-induced alterations in the conformational dynamics of Hsf1 by hydrogen exchange mass spectrometry. We found a temperature-dependent unfolding of Hsf1 in the regulatory region happening concomitant to tighter packing in the trimerization region. The transition to the active DNA binding-competent state occurred highly cooperative and was concentration dependent. Surprisingly, Hsp90, known to inhibit Hsf1 activation, lowered the midpoint temperature of trimerization and reduced cooperativity of the process thus widening the response window. Based on our data we propose a kinetic model of Hsf1 trimerization.
| S-EPMC4775227 | biostudies-literature
Project description:BackgroundThermotolerance is an essential attribute for pathogenesis of Cryptococcus as exemplified by the fact that only two species in the genus, which can grow at 37°C, are human pathogens. Species which have other virulence factors including capsule formation and melanisation, but lack the ability to propagate at 37°C are not pathogenic. In another related fungal pathogen, Candida albicans, heat shock protein 90 has been implicated to be a central player in commanding pathogenicity by governing yeast to hyphal transition and drug resistance. Exploring Hsp90 biology in Cryptococcus in context of thermotolerance may thus highlight important regulatory principles of virulence and open new therapeutic avenues.Methodology/principal findingsHsp90 is involved in regulating thermotolerance in Cryptococcus as indicated by growth hypersensitivity at 37°C upon mild compromise of Hsp90 function relative to 25°C. Biochemical studies revealed a more potent inhibition of ATPase activity by pharmacological inhibitor 17-AAG at 37°C as compared to 25°C. Catalytic efficiency of the protein at 37°C was found to be 6.39×10-5μM-1. Furthermore, indirect immunofluorescence analysis using a specific antibody revealed cell surface localization of Hsp90 via ER Golgi classical secretory pathway. Hsp90 was found to be induced under capsule inducing conditions and Hsp90 inhibition led to decrease in capsular volume. Finally compromising Hsp90 function improved anidulafungin tolerance in Cryptococcus.Conclusions/significanceOur findings highlight that Hsp90 regulates pathogenicity of the fungus by myriad ways. Firstly, it is involved in mediating thermotolerance which implies targeting Hsp90 can abrogate thermotolerance and hence growth of the fungus. Secondly, this study provides the first report of biochemical properties of Hsp90 of a pathogenic fungus. Finally, since Hsp90 is localised at the cell wall, targeting cell surface Hsp90 can represent a novel strategy to combat this lethal infection.
| S-EPMC5559104 | biostudies-literature
Project description:Thermotolerance is a crucial virulence attribute for human pathogens, including the fungus Cryptococcus neoformans that causes fatal meningitis in humans. Loss of the protein kinase Sch9 increases C. neoformans thermotolerance, but its regulatory mechanism has remained unknown. Here, we studied the Sch9-dependent and Sch9-independent signaling networks modulating C. neoformans thermotolerance by using genome-wide transcriptome analysis and reverse genetic approaches. During temperature upshift, genes encoding for molecular chaperones and heat shock proteins were upregulated, whereas those for translation, transcription, and sterol biosynthesis were highly suppressed. In this process, Sch9 regulated basal expression levels or induced/repressed expression levels of some temperature-responsive genes, including heat shock transcription factor (HSF1) and heat shock proteins (HSP104 and SSA1). Notably, we found that the HSF1 transcript abundance decreased but the Hsf1 protein became transiently phosphorylated during temperature upshift. Nevertheless, Hsf1 is essential for growth and its overexpression promoted C. neoformans thermotolerance. Transcriptome analysis using an HSF1 overexpressing strain revealed a dual role of Hsf1 in the oxidative stress response and thermotolerance. Chromatin immunoprecipitation demonstrated that Hsf1 binds to the step-type like heat shock element (HSE) of its target genes more efficiently than to the perfect- or gap-type HSE. This study provides insight into the thermotolerance of C. neoformans by elucidating the regulatory mechanisms of Sch9 and Hsf1 through the genome-scale identification of temperature-dependent genes.
| S-EPMC5223503 | biostudies-literature
Project description:The precise regulation of morphogenesis is a key mechanism by which cells respond to a variety of stresses, including those encountered by microbial pathogens in the host. The polarity protein Cdc42 regulates cellular morphogenesis throughout eukaryotes, and we explore the role of Cdc42 proteins in the host survival of the human fungal pathogen Cryptococcus neoformans. Uniquely, C. neoformans has two functional Cdc42 paralogues, Cdc42 and Cdc420. Here we investigate the contribution of each paralogue to resistance to host stress. In contrast to non-pathogenic model organisms, C. neoformans Cdc42 proteins are not required for viability under non-stress conditions but are required for resistance to high temperature. The paralogues play differential roles in actin and septin organization and act downstream of C. neoformans Ras1 to regulate its morphogenesis sub-pathway, but not its effects on mating. Cdc42, and not Cdc420, is upregulated in response to temperature stress and is required for virulence in a murine model of cryptococcosis. The C. neoformans Cdc42 proteins likely perform complementary functions with other Rho-like GTPases to control cell polarity, septin organization and hyphal transitions that allow survival in the environment and in the host.
| S-EPMC3685590 | biostudies-literature
Project description:Mouse HSF1+/+ and HSF1-/- Fibroblasts Heat Shock Time Courses Scanned on Scanner 7 (Axon 4000B) Set of arrays organized by shared biological context, such as organism, tumors types, processes, etc. Keywords: Logical Set
2005-08-05 | GSE3074 | GEO
Project description:Small heat shock proteins (sHSPs) function as molecular chaperones in multiple physiological processes and are active during thermal stress. sHSP expression is controlled by heat shock transcription factor (HSF); however, few studies have been conducted on HSF in agricultural pests. Liriomyza trifolii is an introduced insect pest of horticultural and vegetable crops in China. In this study, the master regulator, HSF1, was cloned and characterized from L. trifolii, and the expression levels of HSF1 and five sHSPs were studied during heat stress. HSF1 expression in L. trifolii generally decreased with rising temperatures, whereas expression of the five sHSPs showed an increasing trend that correlated with elevated temperatures. All five sHSPs and HSF1 showed an upward trend in expression with exposure to 40 ℃ without a recovery period. When a recovery period was incorporated after thermal stress, the expression patterns of HSF1 and sHSPs in L. trifolii exposed to 40 °C was significantly lower than expression with no recovery period. To elucidate potential interactions between HSF1 and sHSPs, double-stranded RNA was synthesized to knock down HSF1 in L. trifolii by RNA interference. The knockdown of HSF1 by RNAi decreased the survival rate and expression of HSP19.5, HSP20.8, and HSP21.3 during high-temperature stress. This study expands our understanding of HSF1-regulated gene expression in L. trifolii exposed to heat stress.
| S-EPMC8492843 | biostudies-literature