Metabolomics,Unknown,Transcriptomics,Genomics,Proteomics

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Transcription profiling by array to investigate susceptibility to multiple azole resistance in Candida glabrata

ABSTRACT: Transcriptomics analysis of the evolution of a C. glabrata clinical isolate (044) from azole susceptibility to posaconazole resistance (21st day), clotrimazole resistance (31st day) and fluconazole and voriconazole resistance (45th day), induced by longstanding incubation with fluconazole (16mg/mL).

ORGANISM(S): [Candida] glabrata

SUBMITTER: Mafalda Cavalheiro

PROVIDER: E-MTAB-6787 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress

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Project description:Fungal infections are a serious health problem in clinics especially in the immune-compromised patient. Disease ranges from widespread superficial infections like vulvovaginal infections to life-threatening systemic candidiasis. Especially for systemic mycoses only a limited arsenal of antifungals is available. The most commonly used classes of antifungal compounds used include azoles, polyenes and echinocandines. Due to emerging resistance to standard therapy and significant side effects and high costs for several antifungals.,there is a medical need for new antifungals in the clinic and general practice. In order to expand the arsenal of compounds with antifungal activities we previously screened a compound library, using a new type of activity-selectivity (AS) assay analysing both the antifungal activity and the compatibility with human cells at the same time. One compound, ((S)-2-(1-aminoisobutyl)-1-(3-chlorobenzyl) benzimidazole (EMC120B12)), showed high antifungal activity against several species of pathogenic yeasts including C. glabrata and C. krusei, species which are highly refractory to antifungals, especially to the commonly used azoles. Here we could show by transcriptional profiling and sterol analysis that the target of this new antifungal compound is the ergosterol pathway. The effects of EMC120B12 on sterol biosynthesis mimic those of fluconazole, strongly indicating that EMC120B12 also targets ERG11 like the azols. But not only the marker sterol 14 methylergosta 8,24(28) dien 3β,6α diol accumulated in C. krusei under EMC120B12 treatment, but also hitherto unknown related sterols. The novel sterols have a 3β,6α diol structure. Furthermore, this is the first time that a benzimidazole structure has been shown to result in a block of the sterol pathway by accumulating marker sterols connected to ERG11 inactivation. In total, three biological replicates were performed. All experiments were performed as dye swaps. Thus, in total 18 arrays have been hybridzed. Hybridization experiments included an untreated reference sample and a sample of cells treated with either ((1S)-1-[1-(3-chlorobenzyl)-1H-benzimidazol-2-yl]-2-methylpropyl-amine) (EMC120B12), Fluconazole or Nocodazole. The array included one technical replicate of each probe.

Project description:Microarray was used to analyze azole resistance of Candida glabrata oropharyngeal isolates from 7 hematopoietic stem cell transplant recipients receiving fluconazole prophylaxis. Transcriptional profiling of the sequential-paired clinical isolates by microarray revealed 19 genes upregulated in the majority of resistant isolates compared to their paired-susceptible isolates. All seven resistant isolates had greater than two fold upregulation of CgPDR1, a master transcriptional regulator of PDR network, and all 7 resistant isolates showed upregulation of known CgPDR1-target genes. The altered transcriptome can be explained in part by the observation that all 7 resistant isolates had acquired a single nonsynonymous mutation in their CgPDR1 ORF. Four mutations occurred in the regulatory domain (L280P, L344S, G348A, S391L) and one in the activation domain (G943S) while two mutations (N764I, R772I) occurred in an undefined region. Association of azole resistance and the CgPDR1 mutations was investigated in the same genetic background by introducing the CgPDR1 sequences from one sensitive and five resistant isolates into a laboratory azole-sensitive strain (cgpdr1) via integrative transformation. The cgpdr1 strain was restored to wild-type fluconazole susceptibility when transformed with CgPDR1 from the susceptible isolate but became resistant when transformed with CgPDR1 from the resistant isolates. However, despite the identical genetic background, upregulation of CgPDR1 and CgPDR1-target genes varied between the 5 transformants, independent of the domain locations in which the mutations occurred. In sum, gain-of-function mutations in CgPDR1 not only contributed to the clinical azole resistance but different mutations had varying degrees of impact on the CgPDR1-target genes. Seven pairs of oropharyngeal sequential isolates were chosen for study because each pair came from an individual hematopoietic stem cell transplant recipient receiving fluconazole. Seven groups consisted of 5 biological replicates in which a sensitive sample was paired with a resistant sample. Each group included 1 to 2 reciprocally labeled samples.

Project description:We have developed a monoclonal antibody (mAb) C7 that reacts with Als3p and enolase present in Candida albicans cell wall and exerts three anti-Candida activities: candidacidal activity and inhibition of both adhesion and filamentation. To investigate the mode of action of mAb C7 on fungal viability, we examined changes in the genome-wide gene expression profile of C. albicans grown in presence of a subinhibitory concentration of mAb C7 (12.5 µg/ml) by using microarrays. A total of 49 genes were found to be differentially expressed upon treatment with mAb C7. Of these, 28 were found to be up-regulated and 21 down-regulated. The categories of up-regulated genes with the largest number of variations were those involved in iron uptake or related to iron homeostasis (42.86%), while the energy-related group accounted for 38.10% of the down-regulated genes (8/21). Results were validated by real Time PCR. Since these effects resembled those found under iron-limited conditions, the activity of mAb C7 on C. albicans mutants with deletions in key genes implicated in the three iron acquisition systems described in this yeast was also assessed. Only mutants lacking TPK1 and TPK2 genes were less sensitive to the candidacidal effect of mAb C7. FeCl3 or hemin at concentrations ≥ 7.8µM reversed the candidacidal effect of mAb C7 on C. albicans, on a concentration dependent manner. The results presented in this study provide evidence that the candidacidal effect of mAb C7 is related to the blockage of the reductive iron uptake pathway of C. albicans. A saturated culture of C. albicans grown overnight was diluted to an optical density at 600 nm of approximately 0.1 and divided in two aliquots. One of them was used untreated as control and the second one was treated with a subinhibitory concentration (12.5 µg/ml) of monoclonal antibody C7 . Both cultures were incubated for 18 h at 37ºC before harvesting cells. Antibody added and control samples were obtained each time. The experiment was repeated once. Dye-swap technique was used for hybridization and four arrays were analyzed to compare the expresion of over six thousands genes in response to antibody C7.

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Transcription profiling by array to investigate susceptibility to multiple azole resistance in Candida glabrata

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