A long non-coding RNA, afu-254, is required for the oxidative stress response, cell wall stress response, azole susceptibility and virulence in Aspergillus fumigatus

Abstract

Long non-coding RNAs play an important role in stress response in all forms of life; however, a tight regulation of lncRNAs is required for normal function. Abnormal expression of lncRNA is associated with uncontrolled cell growth in many forms of cancer. Recent studies have highlighted the role of lncRNAs in Aspergillus fumigatus in azole stress response and virulence. Here, using a transcriptome dataset of A. fumigatus response to stress, we identified afu-254 as an 854bp lncRNA that plays a role in modulating oxidative stress, fungal sub-MIC azole response to posaconazole and itraconazole, cell wall stress, macrophage phagocytosis and killing ex vivo, and virulence in an invertebrate model of Aspergillus infection. Importantly, afu-254 does not produce cross-azole susceptible response and plays a role in fungal azole response against posaconazole and itraconazole but not voriconazole. Furthermore, we showed that stochiometric levels of afu-254 are important for its function, and ectopic overexpression of afu-254 in the WT strain leads to an antimorph. This phenotype may stem from a higher ordered structure that is denatured with heat, indicating the presence of a non-functional isoform. In conclusion, we characterized a novel lncRNA, afu-254, that is important for stress response and virulence in the pathogenic fungus A. fumigatus. ImportanceFailure of azole treatment for invasive Aspergillus infection by both drug-resistant and drug-sensitive isolates is an area of concern and global importance. Fungal stress response is multifaceted, and long non-coding RNAs have emerged as important players in mediating it, including regulating responses to azole antifungals. Here, we have identified a long non-coding RNA, afu-254, that plays a role in modulating fungal response to oxidative stress, cell wall stress, azole stress, immune cell stress and virulence in an invertebrate model of invasive Aspergillus infection.