The cystic fibrosis treatment Trikafta affects the growth, viability, and cell wall of Aspergillus fumigatus biofilms

Abstract

ABSTRACT People with cystic fibrosis (pwCF) commonly test positive for the pathogenic fungus Aspergillus fumigatus, which is associated with a decline in lung function. Trikafta is a recently approved therapy for pwCF that improves quantity and function of the CFTR protein; however, it is not known how Trikafta affects microbial communities in the lung. Therefore, the aim of this study was to determine whether Trikafta directly affects A. fumigatus growth and biology. While Trikafta did not impact the viability of A. fumigatus conidia, treatment of A. fumigatus biofilms with Trikafta reduced overall biofilm biomass. This finding was associated with increased membrane permeability, decreased viability, and reduced metabolic activity following long-term treatment of biofilms. Trikafta-induced membrane permeability, and biomass reduction was partially blocked with the calcium channel inhibitor verapamil and fully blocked by the mammalian CFTR inhibitor GlyH-101. Trikafta-induced biomass reduction and metabolic activity was shown to be regulated by the high-osmolarity glycerol pathway gene sakA. Trikafta treatment also induced resistance to the cell wall stressor calcofluor white, susceptibility to the anti-fungal drug caspofungin, and decreased inflammatory responses from murine bone marrow cells. Collectively, these results reveal that Trikafta affects infection-relevant A. fumigatus biology and host-microbial interactions. IMPORTANCE PwCF commonly test positive for pathogenic fungi, and more than 90% of the cystic fibrosis patient population is approved for the modulator treatment, Trikafta. Therefore, it is critical to understand how fungal communities, specifically A. fumigatus, respond to Trikafta exposure. Therefore, we sought to determine whether Trikafta impacted the biology of A. fumigatus biofilms. Our data demonstrate that Trikafta reduces biomass in several laboratory strains as well as clinical strains isolated from the expectorated sputum of pwCF. Furthermore, Trikafta reduces fungal viability and the capacity of biofilms to recover following treatment. Of particular importance, Trikafta affects how A. fumigatus biofilms respond to cell wall stressors, suggesting that Trikafta modulates components of the cell wall. Since the cell wall directly affects how a host immune system will respond to and effectively neutralize pathogens, our work, demonstrating that Trikafta impacts the A. fumigatus cell wall, is potentially highly relevant to fungal-induced disease pathogenesis.

Keywords

• Aspergillus fumigatus
• Trikafta
• cystic fibrosis
• anti-fungal agents
• drug susceptibility