MiR-155 deficiency alters heterogeneity of lung immune cells in a mouse model of severe asthma

The lung is a complex tissue comprised of more than 40 cell populations. The interplay among the heterogeneous pulmonary cells is required for proper function and long-term maintenance of lung homeostasis. Because each of the cell populations has a distinct transcriptome, bulk RNA-seq could mask cell-cell crosstalk, cell-type-specific contributions, and relevant networking changes in the lung. To overcome the limitations of bulk tissue analysis, we performed single cell RNA sequencing (scRNA-seq) to investigate the transcriptional profiles of lungs affected by miR-155. Unsupervised clustering analysis revealed 27 different clusters corresponding to distinct cell types of the lung, including epithelial, stromal, endothelial, and leukocyte lineages with specific molecular markers. The miR-155 knockout mice subjected to the severe asthma model showed a decrease in lung immune cells, whereas the numbers of structural cells such as epithelial and endothelial cells were slightly increased compared to their wild type counterparts. We also showed that the transcripts of extracellular trap formation-related genes were substantially down-regulated in miR-155 knockout mice subjected to the severe asthma model. Overall design: Single cell RNA sequencing (scRNA-seq) from wild type and miR-155 knockout mice subjected to the SA model (N=3 each). Library preparation was carried out using 10x Genomics Chromium controller. Chromium 10x Genomics single cell library was sequenced as 150 base pair single-end reads on an Illumina NovaSeq 6000.