Evidence for altered immune-structural cell crosstalk in cystic fibrosis revealed by single cell transcriptomics

Background: 

Chronic pulmonary inflammation strongly contributes to respiratory failure and mortality in patients with cystic fibrosis (pwCF). Effective anti-microbial immunity and maintaining lung homeostasis require continuous structural-immune cell communication. Whether and how this crosstalk is altered in CF remains poorly understood, obscuring potential new angles for therapy development to restore airway homeostasis in pwCF. 

Methods: 

We performed droplet-based single cell RNA-sequencing on bronchial biopsies from pwCF to investigate structural-immune cell crosstalk. Computational analyses were used to compare these data to samples obtained from healthy controls. 

Results: 

CF airway wall biopsies showed lower proportions and altered transcriptomes of basal cells, submucosal gland cells and endothelial cells, and a higher abundance of ciliated cells, monocytes, macrophages and T cells. Both B and T lymphocytes displayed aberrantly activated phenotypes with transcriptional changes linked to hypoxia and vascular endothelial growth factor signaling, indicative of crosstalk with endothelial cells. The CF lung displayed unique changes in intercellular communication potential involving ionocytes, macrophages, endothelial cells and lymphocytes. This included interactions between HLA-E on structural cells and the druggable CD94/NKG2A immune checkpoint on CD8⁺ T cells. 

Conclusions: 

We report the first single cell transcriptome atlas of the CF lung containing the full spectrum of structural and immune cells, providing a valuable resource for investigating changes to cellular composition, phenotypes and crosstalk linked to CF. Our analyses highlight dysregulated basal cell function and adaptive immunity in pwCF – despite favorable responses to CFTR modulator therapy. We identify novel aspects of CF pathophysiology and potential entry points for therapeutic strategies.