RESUMO
Invasive fungal infections cause significant morbidity and mortality among immunocompromised individuals, posing an urgent need for new antifungal therapeutic strategies. Here we investigate a chromatin-interacting module, the bromodomain (BD) from the BET family of proteins, as a potential antifungal target in Candida albicans, a major human fungal pathogen. We show that the BET protein Bdf1 is essential in C. albicans and that mutations inactivating its two BDs result in a loss of viability in vitro and decreased virulence in mice. We report small-molecule compounds that inhibit C. albicans Bdf1 with high selectivity over human BDs. Crystal structures of the Bdf1 BDs reveal binding modes for these inhibitors that are sterically incompatible with the human BET-binding pockets. Furthermore, we report a dibenzothiazepinone compound that phenocopies the effects of a Bdf1 BD-inactivating mutation on C. albicans viability. These findings establish BET inhibition as a promising antifungal therapeutic strategy and identify Bdf1 as an antifungal drug target that can be selectively inhibited without antagonizing human BET function.
Assuntos
Antifúngicos/farmacologia , Candida albicans/efeitos dos fármacos , Candidíase/tratamento farmacológico , Proteínas Fúngicas/antagonistas & inibidores , Terapia de Alvo Molecular , Fatores de Transcrição/antagonistas & inibidores , Sequência de Aminoácidos , Animais , Antifúngicos/síntese química , Compostos Azabicíclicos/síntese química , Compostos Azabicíclicos/farmacologia , Azepinas/farmacologia , Benzodiazepinas/farmacologia , Sítios de Ligação , Candida albicans/crescimento & desenvolvimento , Candida albicans/metabolismo , Candida albicans/patogenicidade , Candidíase/microbiologia , Cristalografia por Raios X , Proteínas Fúngicas/química , Proteínas Fúngicas/genética , Expressão Gênica , Humanos , Camundongos , Modelos Moleculares , Ligação Proteica , Domínios e Motivos de Interação entre Proteínas , Estrutura Secundária de Proteína , Piridinas/síntese química , Piridinas/farmacologia , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Alinhamento de Sequência , Homologia de Sequência de Aminoácidos , Especificidade da Espécie , Fatores de Transcrição/química , Fatores de Transcrição/genética , Triazóis/farmacologiaRESUMO
OBJECTIVES: Antifungal prescription practices have changed over the last decade, and the impact of these changes is unclear. Our objective here was to evaluate the effect of antifungal drug use on the distribution and drug susceptibility of Candida spp. in a French intensive care unit (ICU). METHODS: Antifungal drug use was measured as the number of defined daily doses per 1000 hospital days (DDDs/1000HD). The distribution of Candida spp. over a 6 year period (2004-09) and the MICs of antifungal drugs over 2007-09 were determined. Statistical analyses were performed to assess relationships between antifungal drug use, Candida spp. distribution and MIC changes over time. RESULTS: Of 26,450 samples from 3391 patients, 1511 were positive for Candida spp. Candida albicans predominated (52.5%), followed by Candida glabrata (16.6%) and Candida parapsilosis (7.5%). C. parapsilosis increased significantly, from 5.7% in 2004 to 12.5% in 2009 (P = 0.0005). Caspofungin use increased significantly between 2004 (17.9 DDDs/1000HD) and 2009 (69.9 DDDs/1000HD) (P < 0.0001). Between 2007 and 2009, the increase in caspofungin use correlated significantly with the increase in caspofungin MICs displayed by C. parapsilosis (P < 0.0001) and C. glabrata (P = 0.03). Amphotericin B consumption changed over time and correlated with an increase in amphotericin B MICs for C. albicans (P = 0.0002) and C. glabrata (P = 0.0005). Significant declines occurred in both fluconazole use (P < 0.0001) and fluconazole MICs of C. albicans (P < 0.001) CONCLUSIONS: Antifungal drug use in the ICU is associated with major changes in the distribution and drug susceptibility of Candida spp.