# Single-cell analysis of human airway epithelium identifies cell-type-specific responses to Aspergillus and Coccidioides

## TL;DR

This study uses single-cell RNA sequencing to explore how human airway cells respond to two dangerous fungi, revealing distinct stress responses that could help develop better treatments.

## Contribution

The study provides the first single-cell transcriptional analysis of human airway epithelial cells infected with Aspergillus fumigatus and Coccidioides posadasii.

## Key findings

- Aspergillus fumigatus triggers protein-folding-related stress in ciliated cells.
- Coccidioides posadasii induces hypoxia responses in secretory cells.
- Both fungi cause cellular stress and cytokine production in human airway epithelial cells.

## Abstract

Respiratory fungal infections pose a significant threat to human health. Animal models do not fully recapitulate human disease, necessitating advanced models to study human-fungal pathogen interactions. In this study, we utilized primary human airway epithelial cells (hAECs) to recapitulate the lung environment in vitro and investigate cellular responses to two diverse, clinically significant fungal pathogens, Aspergillus fumigatus and Coccidioides posadasii. To understand the mechanisms of early pathogenesis for both fungi, we performed single-cell RNA sequencing of infected hAECs. Analysis revealed that both fungi induced cellular stress and cytokine production. However, the cellular subtypes affected and specific pathways induced differed between fungi, with A. fumigatus and C. posadasii triggering protein-folding-related stress in ciliated cells and hypoxia responses in secretory cells, respectively. This study represents one of the first reports of single-cell transcriptional analysis of hAECs infected with either A. fumigatus or C. posadasii, providing a vital data set to dissect the mechanism of disease and potentially identify targetable pathways.

Fungal infections in the lungs are lethal complications for those with compromised immune systems and have limited treatment strategies available. These options are restricted further by the increased prevalence of treatment-resistant fungi. Many studies focus on how our immune systems respond to these pathogens, yet airway epithelial cells remain an understudied component of fungal infections in the lungs. Here, the authors provide a transcriptional analysis of primary human airway epithelial cells stimulated by two distinct fungal pathogens, Aspergillus fumigatus and Coccidioides posadasii. These data will enable further mechanistic studies of the contribution of the airway epithelium to initial host responses and represent a powerful new resource for future investigations.