A Platform to Identify Antifungal Compounds with Novel Action Mechanisms

Project Summary There is societal need for new compounds in our arsenal of defenses against fungal pathogens, many of which are increasingly resistant to existing therapeutics. Antifungal compound discovery has been forgotten or neglected (see a review publication 2021 at Research Strategy). One of the best possible sources for new antifungal compounds with potentially novel mechanisms of action is within filamentous fungi, which have the greatest diversity of microbial life. This research proposal advances the science of metagenomics, to demonstrate Aspergillus nidulans as both a heterologous host and an initial antifungal screening target, to integrate with RNA sequencing and fungal pathogen screening of fungal biosynthetic gene clusters (BGCs) and genomes, and to discover novel antifungal chemicals and identify the best lead candidates for clinical development. Scientists at Intact Genomics, and University of Wisconsin at Madison have combined four key technological breakthroughs that result in an improved paradigm for screening small molecules. The improvements in fungal artificial chromosome (FAC) tools include: 1) an improved methodology for heterologous expression of full-length BGC-FACs; 2) the FAC heterologous strains expressing antifungal compounds also showing abnormal phenotypes; 3) new action mechanisms of abnormal phenotype BGC-FACs to be uncovered by RNA deep sequencing; 4) a panel of fungal pathogens for rapid and improved screening method to identify novel antifungal compounds. This Phase I SBIR will build upon the success of previous research by screening FACs for antifungal compounds. We will characterize the antifungal agents expressed by BGC-FAC clones and FAC libraries to determine the best lead candidates for clinical development. Lead candidates will have novel chemical structures, have high potency against multiple fungal pathogens, and minimal toxicity against human red blood cell. Each of the different technologies necessary for the proposed research has been proven effective separately; therefore, the synthesis of these different methods has a high probability of success and also represents a significant advancement for the science of antifungal discovery.