Assessing the cellular microenvironment in the skin of mice lacking epidermal Pparg compared with wildtype sibling controls.

B6.129-Ppargtm2Rev/J mice (Stock Number: 004584, The Jackson Laboratory) were crossed with B6N.Cg-Tg(KRT14-cre)1Amc/J mice (Stock Number 018964, The Jackson Laboratory) to generate epidermal-specific PPAR? knockout mice in the C57BL/6J background (C57.Pparg-/-epi mice). Mice were housed under specific pathogen-free conditions at the Indiana University School of Medicine. The protocols were approved by the Indiana University School of Medicine Institutional Animal Care and Use Committee (IACUC). Using whole transcriptomic RNA sequencing (GSE164024), we had previously demonstrated that the skin of mice lacking epidermal Pparg exhibited signficant changes in approximately 12% of the expressed genes, formed spontaneous inflammatory skin lesions, and had prominent increases in pro-inflammatory genes and a reduction in genes associated with the epidermal lipid barrier function. Mice lacking epidermal Pparg are also prone to increase chemical and photocarcinogenesis. We therefore sought to determine the changes in gene expression at the cellular level to obtain information regarding changes to the cellular microenvironment within the skin of Pparg-/-epi mice. Overall design: Two mice (one male and one female) mice from each genotype were age matched. Skin was excised from areas of telogen phase hair cycling for each mouse. Areas were chosen that lacked evidence of spontaneous inflammatory skin changes. Other than the genotype changes, no treatment was performed on any of the mice. Both dermal and epidermal cells were then isolated for single cell RNA sequencing.