Biology subjects

Poudyal, N. R.

Publications and source records attributed to Poudyal, N. R..

3 recordsLinked to original sources

bioRxiv2026

Thermal adaptation crosstalk with azole response through lncRNA in Aspergillus fumigatus

Fungal pathogens are adapting to increased temperatures altering host-pathogen interactions, disease patterns, and response to the antimicrobial drugs. Here, we show that thermal adaptation to 42{degrees}C leads to reversible changes in fungal colony size and azole drug response in the human pathogenic fungus Aspergillus fumigatus. Importantly, this adaptation is mediated by the lncRNA, afu-182, whose RNA levels negatively correlate with temperature. Growth at a lower temperature or ectopic upregulation of afu-182 RNA levels reverses the temperature adaptation. Previously, we have shown that {Delta}afu-182 strains produce worse disease outcomes in a murine model of invasive pulmonary aspergillosis (IPA). Here, more importantly, we show that the overexpression of afu-182 in clinically azole-resistant isolates increased survival in a murine model of IPA. Taken together, fungal adaptation to increased temperature leads to a decrease in afu-182 RNA levels that is associated with worse disease outcomes upon azole treatment. This provides a framework to take temperature into account when analyzing the rise in azole MIC in environmental and clinical isolates.

microbiology↗

bioRxiv2026

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

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.

microbiology↗

bioRxiv2025

A long non-coding RNA regulates triazole antifungal susceptibility and virulence 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 non-coding RNA, afu-182, is a major regulator of cyp51-independent sub-MIC azole response. We observe that loss of afu-182 leads to increased surface attached growth and poor treated disease outcomes in a murine model of invasive pulmonary aspergillosis upon azole treatment. In contrast, overexpression 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 WT strain. Taken together, our data show a role of the long non-coding RNA afu-182 in regulating Aspergillus fumigatus response to azole drugs both in vitro and in vivo. ImportanceDrug resistance in Aspergillus is a major challenge that is often associated with the agricultural use of azoles in the environment. How drug resistance arises in vivo is still an active area of research. Here, we show that azole exposure results in fungal adaptation by lowering the RNA levels of lncRNA, which upon low dose azole exposure leads to an increase in azole drug MIC.

molecular biology↗