Total RNAs were extracted from each skin biopsy of the volunteers (PR skin, n = 3; UN skin, n = 2) using TRIzol Reagent (Ambion, Austin, Tx, USA) according to the manufacturer's instruction. The next-generation sequencing (NGS) was carried out by a commercial company (Macrogen, Seoul, Korea). Briefly, RNA quality was qualified by an Agilent 2100 bioanalyzer (RIN>7). Libraries for these sequencing were constructed using SMARTer Universal Low Input RNA Kit, TruSeq RNA Sample Prep Kit v2 (pair-end). The cDNAs were checked for the quantity and quality by the bioanalyzer.