AUTHOR=Zhang Zhi-hui , Sun Liu-liu , Fu Bu-qing , Deng Jie , Jia Cheng-lin , Miao Ming-xing , Yang Feng , Cao Yong-bing , Yan Tian-hua 

TITLE=Aneuploidy underlies brefeldin A-induced antifungal drug resistance in Cryptococcus neoformans

JOURNAL=Frontiers in Cellular and Infection Microbiology

VOLUME=Volume 14 - 2024

YEAR=2024

URL=https://www.frontiersin.org/journals/cellular-and-infection-microbiology/articles/10.3389/fcimb.2024.1397724

DOI=10.3389/fcimb.2024.1397724

ISSN=2235-2988

ABSTRACT=Cryptococcus neoformans is at the top of the list of “most wanted” human pathogens. Only 3 classes of antifungal drugs are available for the treatment of cryptococcosis. Study of the antifungal resistance mechanisms is limited to the investigation of how a particular antifungal drug induces resistance to particular drug, yet the impact of stresses other than antifungals on development of antifungal resistance and even cross-resistance is largely unexplored. Endoplasmic reticulum (ER) is a ubiquitous subcellular organelle of eukaryotic cells. Brefeldin A is a widely used chemical inducer of ER stress. Here we found both weak and strong selection by brefeldin A caused aneuploidy formation in C. neoformans, mainly disomy of chromosome 1, chromosome 3 and chromosome 7. Disomy of chromosome 1 conferred cross-resistance to 2 classes of antifungal drugs: fluconazole and 5-flucytosine, as well as hypersensitivity to amphotericin B. However, drug resistance was unstable, due to the intrinsic instability of aneuploidy. We found overexpression of AFR1 on Chr1 and GEA2 on Chr3 phenocopied BFA resistance conferred by chromosome disomy. Overexpressoin of AFR1 also caused resistance to fluconazole and hypersensitivity to amphotericin B. Furthermore, strain with deletion of AFR1 failed to form chromosome 1 disomy upon BFA treatment. Transcriptome analysis indicated chromosome 1 disomy simultaneously up-regulated AFR1, ERG11 as well as other efflux and ERG genes. Thus, we posit BFA have the potential of driving rapid development of drug resistance and even cross-resistance in C. neoformans, and the genome plasticity is the accomplice.