title: Illumina HiSeq 2500 paired end sequencing; RNA-sequencing of the mRNA transcriptome in lesional and non-lesional skin, across three time-points in severe psoriasis patients treated with the tumor necrosis factor (TNF) inhibitor, etanercept
design: RNA-sequencing of the mRNA transcriptome in lesional and non-lesional skin, across three time-points in severe psoriasis patients treated with the tumor necrosis factor (TNF) inhibitor, etanercept
library_construction_protocol: Samples including lesional and non-lesional skin samples, were taken at each participant visit. Skin biopsies (6mm punch biopsies) were taken from lesional (edge of a plaque) and adjacent (minimum distance of 2cm) non-lesional skin from photoprotected sites on the lower back or upper buttock at each visit. Repeat biopsies were taken at a minimum distance of 2cm and biopsy sites were recorded.  The dose of etanercept for all included participants was: Etanercept subcutaneous administration 25mg twice weekly (administered either as 25mg twice weekly or 50mg once weekly). mRNA was extracted from skin biopsies using Qiagen Rneasy mini kits Libraries were prepared with the TruSeq Stranded Total RNA Sample Preparation Kits. The first step involved removal of ribosomal RNA (rRNA), conducted using biotinylated Ribo-Zero rRNA removal beads. For RNA extracted from skin, the Ribo-Zero Gold kit was used to deplete samples of cytoplasmic and mitochondrial rRNA.