Effect of hematopoietic Tet2 KO on emphysema development. (A) Schematic of experimental approach for mice treated with CS and poly(I:C). (B) Representative images of airspace destruction (Gill’s stain imaged at ×10 magnification) in Tet2 WT and Tet2 KO mice (left) and quantification of emphysema in Tet2 WT (n = 10) and Tet2 KO (n = 10) mice exposed to CS and poly(I:C). Error bars indicate standard error of the mean. (C) UMAP visualization of single-cell RNA sequencing data shows clustering of 25 cell types that were identified in the lungs of Tet2 WT and Tet2 KO mice. (D) Assessment of signature scores in the single-cell transcriptional data of mice exposed to CS and poly(I:C) across all cells for IFN and tumor growth factor β (TGFB) gene sets obtained from Hallmark (H), Reactome (R), Biocarta (B), KEGG (K), or Wikipathways (W). A positive value (blue) represents higher scores in Tet2 WT (WT), and a negative value (orange) reflects higher scores in Tet2 KO mice. The P values were calculated using a Wilcoxon test and adjusted (adj) using a Bonferroni correction. (E-F) For each cluster of cells, the mean of cell signature scores for (E) IFN-α and (F) IFN-γ was determined and plotted for Tet2 WT (y-axis) and Tet2 KO (x-axis) animals. Clusters above the line of identity are enriched for the signature in Tet2 WT mice; clusters that fall below are enriched for the signature in Tet2 KO mice. Clusters in red have significantly higher scores in Tet2 KO mice with the size of each cluster representing the significance of difference between the Tet2 KO and Tet2 WT groups. AM, alveolar macrophage; AT1, alveolar type 1; AT2, alveolar type 2; CEC, circulating endothelial cell; DC, dendritic cell; DN, double negative; EC, endothelial cell; IM, interstitial macrophage; LEC, lymphatic endothelial cell; Mig DC, migratory dendritic cell; NK, natural killer [cell]; P, Pvalue; pDC, plasmacytoid dendritic cell; SMC, smooth muscle cell; Treg, regulatory T cell. pIpC, poly(I:C).