Aspergillus fumigatus transcription factors involved in the caspofungin paradoxical effect, supplementary files

Aspergillus
fumigatus is the leading cause of pulmonary fungal diseases.
Azoles have been used for many years as the main antifungal agents to treat and
prevent invasive aspergillosis. However, in the last ten years there are
several reports of azole resistance in A.
fumigatus and new strategies are needed to combat invasive aspergillosis.
Caspofungin is effective against other human fungal pathogens, but it is only
fungistatic against A. fumigatus. Resistance to caspofungin in A. fumigatus have been linked to mutations in the fksA gene that encodes the target enzyme
of the drug, β-1,3-glucan synthase. However, tolerance to high caspofungin
concentrations, a phenomenon known as caspofungin paradoxical effect (CPE), is
also important for subsequent adaptation and drug resistance evolution. Here,
we have identified and characterized the transcription factors involved
in the response to CPE by screening an A.
fumigatus library of 484 null transcription factors (TFs) in CPE drug
concentrations. We have identified eleven TFs that had reduced CPE encoding
proteins involved in the basal modulation of the RNA polymerase II initiation
sites, calcium metabolism and cell wall remodelling. One of theseTFs FhdA was
important for mitochondrial respiratory function and iron metabolism. The ΔfhdA mutant
had decreased growth when exposed to Congo Red or at high temperature. RNAseq
analysis and further
experimental validation indicate that the ΔfhdA
mutant showed diminished respiratory capacity, probably affecting several
pathways related to the caspofungin tolerance and resistance. Our results
provide the foundation to understand signaling pathways that are important for
caspofungin tolerance and resistance.