Project description:Aging is a normal physiological phenomenon of organisms. Skin aging is a specific manifestation of aging of local human organs. In this study, we used mass spectrometry to perform non-invasive analysis of the skin of 20 healthy young and elderly people in China. Quantitative proteomic analysis identified differentially expressed proteins.
Project description:Healthy skin maintains a diverse microbiome and a potent immune system to fight off infections. In this study, we discovered that epithelium-derived antimicrobial peptides defensins activate orphan GPCRs Mrgpra2a/b on neutrophils. This signaling axis is required for effective neutrophil-mediated skin immunity and microbiome homeostasis. We generated two mutant mouse lines, Defensin conditional knockout (Def cKO, K14-cre; Def fl/fl) in which the entire Def gene cluster is conditionally deleted from keratinocytes, and Mrgpra2 double knockout (Mrgpra2 dKO). We used high-throughput RNA sequencing to evaluate the whole transcriptomes of WT and mutant animals' skin under naive condition and 24 hours post-S. aureus infection. Disruption of defensin-Mrgpra2 signaling caused reduction of a network of pro-inflammatory and antibacterial gene expression. This study demonstrates the importance of epithelial-neutrophil signaling via the defensin-Mrgpra2 axis in maintaining healthy skin ecology and promoting antibacterial host defense.