Author:
C Gutierrez Perez1*, S Dhingra1,2, SM Kwansy3, TJ Opperman3, RA Cramer1
Author address:
1Microbiology and Immunology , Dartmouth College, Hanover, NH, USA
2Biological Sciences, Clemson University, Clemson, SC, USA
3, Microbiotix Inc , Worcester, MA, USA
Full conference title:
10th Advances Against Aspergillosis and Mucormycosis
Date: 2 February 2022
Abstract:
Purpose:
Aspergillus fumigatus is a ubiquitous airborne filamentous fungus that is estimated to contribute to 600,000 deaths each year. There are currently only three contemporary antifungal therapies to treat invasive Aspergillus infections. Rapidly increasing resistance to first line therapy voriconazole highlights a significant need to develop novel antifungals with innovative mechanisms of action. Research from our lab has shown that the hypoxia response, mediated by the transcriptional regulator SrbA, is necessary for virulence and azole resistance in Aspergillus fumigatus. Therefore, identifying a compound that inhibits the SrbA mediated hypoxia response pathway would introduce a potentially novel antifungal that could potentiate azoles activity in vivo.
Methods:
We designed and performed a high-throughput screen by adapting a gpdA-luciferase reporter system to screen over 200,000 small molecule compounds for antifungal activity in the presence of fluconazole or hypoxic conditions. Using a secondary screen measuring enhanced fluconazole sensitivity and hypoxia specificity, we confirmed 50 compounds that fit all parameters to date. We then prioritized compounds that show limited human toxicity and an MIC≤10 µM for further investigation.
Results:
Increased SrbA expression through expression of the N terminus bHLH transcription reduces susceptibility to several of these molecules. These data suggest that the compounds may act on the SrbA dependent hypoxia response. Since SrbA pathway inhibition increases azole sensitivity, we next tested the compounds against voriconazole-resistant clinical isolates and determined that combination therapy increases voriconazole efficacy.
Conclusion:
Using this high-throughput screen and follow up secondary screens we have identified compounds that are hypoxia specific and potentiate azole therapy with minimal human toxicity. Additionally, preliminary data suggests that several compounds are acting through the SrbA dependent hypoxia response pathway, a well characterized virulence factor. Through this work we are finding that we can identify novel antifungal compounds that act through innovative and well characterized biological mechanisms. One potential application of these findings is that these compounds can be used in combination therapy to potentiate azoles and combat antifungal resistance.
Abstract Number: 93
Conference Poster: https://www.aspergillus.org.uk/wp-content/uploads/2022/04/93.pdf
Conference Year: 2022
Link to conference website: https://aaam2022.org/
URL Conference abstract: