Age-related loss of innate immune antimicrobial function of dermal fat is mediated by TGFβ

Dermal fibroblasts (dFB) resist infection by locally differentiating into adipocytes and producing the antimicrobial peptide cathelicidin in response to S. aureus. We found that neonatal dFB were highly adipogenic whereas this adipogenic function was lost during adulthood. To better understand the molecular nature of the change in antimicrobial and adipogenic function of dFB, we profiled the transcriptomes of primary dFB isolated at different ages by RNA-seq. RNA-seq identified the pro-adipogenic to pro-fibrotic gene signature switch in dFB during aging, and identified TGF-beta as the top up-regulated pathway that was activated in 2M dFB compared to neonatal P1 dFB. Examination of differentially expressed genes in cultured primary dermal fibroblasts/pre-adipocytes isolated from mouse skin with various ages.