Non-invasive human skin transcriptome analysis using mRNA in skin surface lipids

Non-invasive acquisition of mRNA data from the skin would be extremely useful for understanding skin physiology and diseases. Inspired by the holocrine process, in which the sebaceous glands secrete cell contents into the sebum, we focused on the possible presence of mRNAs in skin surface lipids (SSLs). We found that measurable human mRNAs exist in SSLs, where sebum protects them from degradation by RNases. The AmpliSeq transcriptome analysis was modified to measure SSL-RNAs, and our results revealed that SSL-RNAs predominantly contained mRNAs derived from sebaceous glands, epidermis, and hair follicles. Analysis of SSL-RNAs non-invasively collected from patients with atopic dermatitis revealed significantly increased expression of inflammation-related genes and decreased expression of terminal differentiation-related genes, consistent with the results of previous reports. Further, we found that lipid synthesis-related genes were downregulated in the sebaceous glands of patients with atopic dermatitis. These results indicate that the analysis of SSL-RNAs is promising to understand the pathophysiology of skin diseases.