Systematic screening and identification of novel psoriasis-specific genes from the transcriptome of psoriasis-like keratinocytes

Psoriasis is a chronic inflammatory skin disease. Keratinocytes (KCs), as skin-specific cells, serve an important role in the immunopathogenesis of psoriasis. In the present study, transcriptome data derived from psoriasis-like KCs were used together with the reported transcriptome data from the skin/epidermis of patient with psoriasis, excluding known psoriasis-associated genes that have been well described in the previous studies according to GeneCards database, to screen for novel psoriasis-associated genes. According to the human expressed sequence tag of UniGene dataset, six genes that are located near psoriasis-associated loci were highly expressed in skin. Among these six genes, four genes (epiregulin, NIPA like domain containing 4, serpin family B member 7 and WAP four-disulfide core domain 12) were highly expressed in normal mouse epidermis (mainly KCs) and mouse psoriatic epidermis cells, but not in psoriatic dermis cells, which further emphasized the specificity of these genes. Furthermore, in systemic inflammatory response syndrome (SIRS), SERPINB7 showed no difference in expression in immune-activated tissues from SIRS and control mice. It was also found that the mRNA expression levels of SERPINB in lesional skin of patients with psoriasis were significantly higher than in non-lesional psoriatic skin from the same patients. SERPINB7 may be a valuable candidate for further studies. In the present study, a method for identifying novel key pathogenic skin-specific molecules is presented, which may be used for investigating and treating psoriasis.