Figure 5.

Impact of smoke exposure on differentiating small airway epithelial cells. (a) Experimental design to investigate the impact of chronic cigarette smoke exposure throughout differentiation contrasted with the design applied to examine the effect of acute smoke exposure. (b) T-SNE plots represent the integrated scRNA-seq data sets of both experiments and depict annotated cell (sub)populations (upper panel) as well as the experimental origin (lower panel, left) and smoking status (lower panel, right) of the cells. (c–e) Smoke-induced shifts of selected SC and BC subpopulation frequencies and the total IC frequency after chronic smoke exposure throughout differentiation. Data of the respective HC and COPD donors are connected. (f) KRT6A⁺ BC frequency in SAEC ALI cultures chronically exposed to smoke during differentiation compared to acute smoke exposure. (g) Summary of the significantly up- and down-regulated genes (adj. p < 0.05, abs. fold change ≥1.5) after chronic smoke exposure across the main SAEC populations (BC, IC, SC and CC according to the color code in (i)) of HC and COPD donors (n = 3, each). Core genes de-regulated in at least two cell types are summarized in the center (violet circle). (h) Comparison of the total gene sets significantly de-regulated by chronic smoke exposure in at least one of the four main cell populations of HC and COPD donors. (i) Relative expression of selected genes from the core gene set that are associated with cellular detoxification/oxidative stress and inflammatory/antimicrobial response across the four main SAEC populations. Average gene expression is shown for air control and smoke-exposed (chronic) cells from both, HC and COPD donors. (j) Impact of chronic smoke exposure on cilia function as determined by the area covered by active cilia and frequency of cilia beating.