In vivo gene signature of human skin with CO2 laser treatment

How developmental programs reactivate in regeneration is a fundamental question in biology. We addressed this question through the study of Wound Induced Hair follicle Neogenesis (WIHN), an adult organogenesis model where stem cells regenerate entirely new hair follicles de novo following deep wounding. The exact mechanism is uncertain. Here we show that self-noncoding dsRNA activates the anti-viral receptor TLR3 to induce intrinsic retinoic acid (RA) synthesis in a gradient that predicts new hair follicle formation after wounding in mice. Additionally, in humans, rejuvenation lasers induce gene expression signatures for dsRNA and RA, with measurable increases in intrinsic RA synthesis. These results demonstrate a novel stimulus for retinoic acid synthesis by non-coding dsRNA, relevant to their broad functions in development and immunity. The goal of this study is to investigate whole genome analysis in human skin with CO2 laser treatment, which leads to enhanced skin rejuvenation. Under Hopkins IRB (IRB00028768), 17 Caucasian women Fitzpatrick types I-III with average age of 55 and moderate to severe baseline photoaging were enrolled. Laser treatments and biopsy schedule were as listed, with treatments occurring both to the arm, and arm biopsies used for gene expression data listed. Analysis was performed on 32 skin samples from 16 individuals, of which 16 were control biological replicates and 16 were matched laser-treated biological replicates.