Detection of circadian gene expression in human epidermal suction blister samples

To detect time of day dependent gene expression in human epidermis suction blister samples from 20 healthy subjects were obtained at three different time points throughout the day. RNA from 20 subjects were used to perform whole genome microarray analysis. Microarrays from 19 subjects showed sufficient quality to perform analysis for differential gene expression. We detected significant differential expression levels for several canonical clock genes such as Per1, Per2, Per3, Bmal1 and Rev-Erb_alpha throughout the day. In total we identified 294 genes that showed significant circadian gene expression including several transcription factors and rate limiting enzymes. To our knowledge this is the first study to investigate genome wide circadian gene expression in human epidermis. Suction blisters of human epidermis were obtained by applying a vacuum for approximately 2.5 h. Suction blisters for each subject (19 subjects in total) were harvested at 9.30 am, 2.30 pm and 7.30 pm.