Project description:New antifungal drugs are urgently needed due to the currently limited selection, the emergence of drug resistance, and the toxicity of several commonly used drugs. To identify drug leads, we screened small molecules using a Saccharomyces reporter bioassay in which the yeast heterologously expresses Hik1, a group III hybrid histidine kinase (HHK) from Magnaporthe grisea. Group III HHKs are integral in fungal cell physiology, and highly conserved throughout this kingdom; they are absent in mammals, making them an attractive drug target. Our screen identified compounds 13 and 33, which showed robust activity against numerous fungal genera including Candida, Cryptococcus and molds such as Aspergillus and Rhizopus. Drug-resistant Candida from patients were also highly susceptible to compounds 13 and 33. While the compounds do not act directly on HHKs, microarray analysis showed that compound 13 induced transcripts associated with oxidative stress, and compound 33, transcripts linked with heavy metal stress. Both compounds were highly active against Candida biofilm, in vitro and in vivo, and exerted synergy with fluconazole, which was inactive alone. Thus, we identified potent, broad-spectrum antifungal drug leads from a small molecule screen using a high-throughput, yeast reporter bioassay. Two-color experimental design testing the effects of 2 antifungal compounds (13 and 33) after 0, 20, 40 60 min. In the referred publication, the t=20, 40, 60 data was normalized against the t=0 data
Project description:New antifungal drugs are urgently needed due to the currently limited selection, the emergence of drug resistance, and the toxicity of several commonly used drugs. To identify drug leads, we screened small molecules using a Saccharomyces reporter bioassay in which the yeast heterologously expresses Hik1, a group III hybrid histidine kinase (HHK) from Magnaporthe grisea. Group III HHKs are integral in fungal cell physiology, and highly conserved throughout this kingdom; they are absent in mammals, making them an attractive drug target. Our screen identified compounds 13 and 33, which showed robust activity against numerous fungal genera including Candida, Cryptococcus and molds such as Aspergillus and Rhizopus. Drug-resistant Candida from patients were also highly susceptible to compounds 13 and 33. While the compounds do not act directly on HHKs, microarray analysis showed that compound 13 induced transcripts associated with oxidative stress, and compound 33, transcripts linked with heavy metal stress. Both compounds were highly active against Candida biofilm, in vitro and in vivo, and exerted synergy with fluconazole, which was inactive alone. Thus, we identified potent, broad-spectrum antifungal drug leads from a small molecule screen using a high-throughput, yeast reporter bioassay.
Project description:Fungal infections are a serious health problem in the clinic especially in the immunocompromised patient. Disease ranges from widespread superficial vulvovaginal infections to life-threatening systemic candidiasis. Especially for systemic mycoses only a limited arsenal of antimycotica are available, including azoles, polyenes, echinocandines and amphothericin B. Due to emerging resistance to standard therapy and significant side effects for some antimycotica 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 screened compound libraries, including combinatorial libraries as well as more than 30 000 pure compounds derived from organic synthesis for antimycotic activity. In total more than 100 000 compounds were screened using an innovative AS (activity-selectivity) assay analyzing both the antifungal activity and the compatability with human cells at the same time. One promising hit, a Benzimidazol-2-yl-alkylamine derivative, was developed in a series of lead compounds showing potent antifungal activity. ((1S)-1-[1-(3-chlorobenzyl)-1H-benzimidazol-2-yl]-2-methylpropyl-amine) (EMC120B12) showed the highest antifungal activity and best compatability with human cells in several cell culture models and against a number of different yeasts and clinical isolates. Transcriptional profiling indicates that the newly discovered compound is a potential inhibitor of the ergosterol-pathway.
Project description:Fungal infections are a serious health problem in the clinic especially in the immunocompromised patient. Disease ranges from widespread superficial vulvovaginal infections to life-threatening systemic candidiasis. Especially for systemic mycoses only a limited arsenal of antimycotica are available, including azoles, polyenes, echinocandines and amphothericin B. Due to emerging resistance to standard therapy and significant side effects for some antimycotica 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 screened compound libraries, including combinatorial libraries as well as more than 30 000 pure compounds derived from organic synthesis for antimycotic activity. In total more than 100 000 compounds were screened using an innovative AS (activity-selectivity) assay analyzing both the antifungal activity and the compatability with human cells at the same time. One promising hit, a Benzimidazol-2-yl-alkylamine derivative, was developed in a series of lead compounds showing potent antifungal activity. ((1S)-1-[1-(3-chlorobenzyl)-1H-benzimidazol-2-yl]-2-methylpropyl-amine) (EMC120B12) showed the highest antifungal activity and best compatability with human cells in several cell culture models and against a number of different yeasts and clinical isolates. Transcriptional profiling indicates that the newly discovered compound is a potential inhibitor of the ergosterol-pathway. In total, three biological replicates were performed. All experiments were performed as dye swaps. Thus, in total six arrays have been hybridzed. Hybridization experiments included an untreated reference sample and a sample of cells treated with ((1S)-1-[1-(3-chlorobenzyl)-1H-benzimidazol-2-yl]-2-methylpropyl-amine) (EMC120B12). The array included one technical replicate of each probe.
Project description:Candida albicans is a commensal yeast within the human microbiota with significant medical importance because of its pathogenic potential. The yeast produces biofilms, which are highly resistant to available antifungals. High level of antifungal resistance by C. albicans biofilms has resulted in the need for alternative treatment. Polyunsaturated fatty acids such as arachidonic acid has been reported to increase the susceptibility of C. albicans biofilms to azole. However, the underlining mechanism is unknown. To unravel the mechanism behind this phenomenon, identification of differentially regulated genes in C. albicans biofilms grown in the presence of arachidonic acid, fluconazole, and the combination of both compounds was conducted using RNAseq.
Project description:Combination therapies can be a promising tool to augment the antifungal activity of azole drugs against resistant Candida species. Here, we report the interaction between aprepitant, an antiemetic agent, and azole drugs against different Candida species including the emerging multidrug-resistant C. auris. Particularly, aprepitant enhanced the antifungal activity of itraconazole against C. auris by reducing its minimum inhibitory concentration (MIC) by 2-8 folds. Using Caenorhabditis elegans as an in vivo infection model, the aprepitant/itraconazole combination significantly prolonged the survival of the infected nematodes by ~90% and reduced the fungal burden by ~92% relative to the untreated control. Interestingly, the aprepitant/itraconazole combination exerted a potent fungicidal activity against both planktonic and adherent C. auris biofilms. Further, aprepitant/itraconazole displayed broad-spectrum synergistic interactions against other medically important Candida species including C. albicans, C. krusie, C. tropicalis, and C. parapsilosis (ƩFICI ranged from 0.08 to 031). Comparative transcriptomic profiling indicated aprepitant/itraconazole interferes significantly with metal ions homeostasis and compromises the ROS (reactive oxygen species) detoxification ability of C. auris. This study presents aprepitant as a novel, potent and broad-spectrum azole chemosensitizing agent that warrants further investigation.
Project description:To investigate the mode of action of a novel class of antifungal synthtic acrylamide peptides, the pathogenic yeast, Candida albicans, was exposed to sublethal doses of peptides with different structures. The experiments include the most effective structure, LH, peptides with no antifungal effects (HEAm) and intermediates as well as controls.
Project description:Fungal group III histidine kinases are the molecular targets of some classes of fungicides. In contrast to the yeast Saccharomyces cerevisiae, the fungal pathogen Candida albicans possesses a group III histidine kinase, CaNik1p, also called Cos1p. To investigate the function of CaNIK1, the gene was expressed in S. cerevisiae. The transformants became susceptible to antifungal compounds to which the wild-type strain is resistant. The susceptibility was related to the activation of the MAP kinase Hog1p of the osmotic stress response pathway. Gene expression analysis revealed a strong overlap of the responses to osmotic stress and to fludioxonil at early time points. While the response to fludioxonil persisted, the response to osmotic stress was diminished with time.
Project description:As innate immune cells, monocytes play a central role in antifungal immunity. Using proteome studies in primary human monocytes, which were stimulated by Candida albicans (yeast) in vitro. Here we describe the changes of proteins in monocytes and demonstrate that in the early stage of infection, the differences of innate immune response triggered by C. albicans over time.