Single cell transcriptomic analysis (InDrops) of mouse mesenchymal stromal cells (mSCs or FAPs, fibro-adipogenic progenitors) isolated from lymph node, muscle and visceral adipose tissue

Regulatory T cells (Tregs) are key brakes on the VAT inflammation that regulates local and systemic metabolic tenor. The cytokine, IL-33, expands and sustains the unique Treg population residing within VAT. Making use of single-cell RNA sequencing, we identified the major IL-33 producers in VAT to be particular mSC subtypes, related to but distinct from adipocyte progenitor cells. We further characterize these subsets by individually isolating them and performing bulk-RNA sequencing. We explored modulation of the VAT-mSC (VmSC) landscape with physiologic variables such as age and sex, as well as pathogenic states like obesity. We uncovered a VAT Treg:stromal-cell negative regulatory loop that keeps the potent effect of IL-33 under rein. Single cells were sorted by flow cytometry for single cell RNAseq library preparation (InDrops)