Single cell RNA-seq and machine learning reveal novel subpopulations and regulatory sequences in low-grade inflammatory monocytes

We report the application of single-cell RNA sequencing(scRNA-seq) in mouse monocyte cells by integrating scRNA-seq, transcriptionfactor binding motifs, and ATAC-seq data using machine learning. We generated scRNA-seqdata from mouse monocytes treated with PBS, SD-LPS, 4-PBA, and SD-LPS + 4-PBA tounderstand the gene regulatory networks of monocytes under the low-grade inflammatorycondition and the mechanism of action for 4-PBA. We find two novelsubpopulations of monocyte cells in response to SD-LPS. We show that 4-PBApotently reprograms an anti-inflammatory monocyte phenotype and masks theeffects of subclinical low dose LPS. Together with TF binding motifs and ATAC-seqdata, a machine learning method, using guided, regularized random forest (GRRF)and feature selection was developed to select the best candidate TFs that areinvolved in the activation of monocytes within different clusters. Our results suggestthat our new machine learning method can select candidate regulatory genes aspotential targets for developing new therapeutics against low-gradeinflammation. Analysis of gene expression of mouse monocytes treated with PBS, SD-LPS, 4-PBA, and SD-LPS + 4-PBA at the single cell level