Project description:The limited number of antifungals and the emergence of multidrug-resistant Candida auris pose a significant challenge to human medicine. Here, we utilized combinatorial drug therapy as an approach to augment the activity of current azole antifungals against C. auris. We evaluated the fluconazole chemosensitization activity of 1547 FDA-approved drugs and clinical molecules against an azole-resistant strain of C. auris. This led to the discovery that lopinavir, an antiviral drug, is a potent agent capable of sensitizing C. auris to the effect of azole antifungals. At a therapeutically achievable concentration (4-8 µg/ml), lopinavir exhibited potent synergistic interactions with azole drugs, particularly with itraconazole, against C. auris (ΣFICI ranged from 0.05-0.50). The lopinavir/itraconazole combination enhanced the survival rate of C. auris-infected Caenorhabditis elegans by 90% and reduced the fungal burden in infected nematodes by 88.5% (p < 0.05). Moreover, lopinavir enhanced the antifungal activity of itraconazole against other medically important Candida species including C. albicans, C. tropicalis, C. glabrata, C. tropicalis, and C. parapsilosis. Comparative transcriptomic profiling revealed that lopinavir interferes with glucose permeation and ATP synthesis. This compromises the function of the efflux pumps presents in C. auris enhancing sensitivity to azole antifungals, as demonstrated by Nile red efflux assays. This study presents lopinavir as a novel, potent and broad-spectrum azole chemosensitizing agent that warrants further investigation against recalcitrant Candida infections.
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:Multidrug resistance in the pathogenic fungus Candida glabrata is a growing global threat. Here, we study mechanisms of multidrug resistance in this pathogen. Exposure of C. glabrata cells to micafungin (an echinocandin) leads to the isolation of a mutant exhibiting resistance to echinocandin and azole antifungals. The drug-resistant phenotype is due to a non-synonymous mutation (R70H) in gene IPI1, which is known to be involved in pre-rRNA processing in Saccharomyces cerevisiae. Azole resistance in the ipi1-R70H mutant depends on the Pdr1 transcription factor, which regulates the expression of multidrug transporters. We show that the C. glabrata Ipi1 protein physically interacts with the ribosome-related chaperones Ssb and Ssz1, both of which bind to Pdr1. The Ipi1-Ssb/Ssz1 complex inhibits Pdr1-mediated gene expression and multidrug resistance in C. glabrata, in contrast to S. cerevisiae where Ssz1 has been shown to act as a positive regulator of Pdr1. Furthermore, micafungin exposure reduces metabolic activity and cell proliferation in the ipi1-R70H mutant, which may contribute to micafungin tolerance.