Proteomic analysis from skin swabs reveals a new set of proteins identifying skin impairment in Atopic Dermatitis

Atopic Dermatitis (AD) is a common inflammatory skin disease characterized by skin and systemic inflammation, and barrier dysfunction. Herein, we investigate the proteomic profile of AD skin barrier to identify a unique signature with an easy-performed sampling approach. We enrolled 8 moderate-to-severe AD patients and 8 age- and gender-matched heathy controls. Swabs were obtained from non-lesional skin of retroauricular area and antecubital fold. Peptide mixtures obtained through protein precipitation and in-solution digestion were analyzed using NanoLC-MS/MS. Label-free quantification and statistical analysis were conducted in MaxQuant and Perseus. Bioinformatics analysis were performed using Gene Ontology and STRING. We identified 908 proteins and 35 differentially expressed proteins were selected (fold change 2, FDR <0.05). Particularly, AD skin showed downregulation of skin hydration factors, structural and epidermal proteins, abnormalities in protease-proteasome complex and lipid metabolism profile. Imbalance of antioxidant and inflammatory processes, along with TDRD15 upregulation were also observed. Our result showed partial overlap with skin biopsy/tape-strips studies, showing the reliability of our sampling approach which could be an easier method of detection of hallmark barrier proteins in AD. Furthermore, we displayed a new differentially expressed set of proteins, not yet explored in AD which can have a potential role in AD pathomechanisms.