A long noncoding RNA regulates in vitro and in vivo triazole antifungal susceptibility in Aspergillus fumigatus.

Azole-resistant Aspergillus infections are a source of increasing concern with limited alternative therapeutic options. However, as most infections are still caused by azole-susceptible Aspergillus strains, there is a need to better understand fungal responses to azole antifungals. To this end, we discover that a long noncoding RNA, afu-182, is a major regulator of cyp51-independent sub-minimum inhibitory concentration (MIC) azole response. We observe that the loss of afu-182 leads to increased surface-attached growth and poorer disease outcomes in a murine model of invasive pulmonary aspergillosis upon azole treatment. In contrast, OE of afu-182 significantly reduces fungal burden in animals treated with the azole drug posaconazole. Importantly, afu-182 levels decrease upon azole exposure, and in an azole adaptation experiment, continuous exposure to low-dose azole led to MIC increase in an afu-182-dependent manner. Whole transcriptome analyses revealed that azole drug treatment leads to an increase in transcripts of genes encoding 7-transmembrane domain proteins of the RTA1 family, and these proteins are negatively regulated by afu-182. Two RTA1 family genes have individual and combined effects and are sufficient to increase fungal susceptibility to azole drugs in the wildtype (WT) strain. Taken together, our data show a role of the long noncoding RNA afu-182 in regulating Aspergillus fumigatus response to azole drugs both in vitro and in vivo.