P112 An exclusive established cell model of patient-derived psoriatic keratinocyte provides a valuable <i>in vitro</i> tool for mechanistic studies and therapeutic testing

Abstract Chronic inflammatory skin conditions, including psoriasis, result in a wide range of distressing symptoms for affected individuals. There is a pressing need for epidermal models which can be readily utilized, enhancing our comprehension of these disorders. We report, the establishment of a novel psoriatic keratinocyte cell line that embodies essential features of psoriasis. Psoriatic keratinocytes (PSA cells), isolated from epidermal hypertrophic plaques of a 50-year-old male with psoriasis vulgaris, and a control keratinocyte (KT2) cell line, derived from an aged-matched healthy human skin sample, were immortalized with SV40-large T antigen. The transcriptomic and biological analysis of these established cellular models revealed significant phenotypic distinctions between healthy and psoriatic keratinocytes. Our findings from RNA-seq data analysis (validation by qRT-PCR) demonstrate that PSA cells from psoriatic individuals display a heightened expression profile of inflammatory cytokines and peptides (including TNF-α, IL-1β, IL-23, IL-8, LL-37, and serpin B1) compared with KT2 cells from healthy individuals, mirroring the clinical characteristics observed in psoriasis patients. Stimulation of the cells for 24 h with phorbol myristate acetate (PMA) which induces reactive oxygen species (ROS) production and protein kinase C (PKC) activation, ultimately leading to an inflammatory response further increased most of cytokine’s expression in PSA cells when compared with non-treated KT2 cells. This confirms that the psoriatic cell model is capable of launching additional inflammatory responses upon exposure to stress factors, in addition to their already innate inflammatory nature. Additional comparative analysis of PSA cells and KT2 cells in conjunction with NTERT cells, a healthy keratinocyte line conventionally used in cutaneous research, found that the PSA cells exhibited reduced expression of anti-inflammatory glucocorticoid receptor, comparable to what detected in primary keratinocytes isolated from psoriatic lesional and non-lesional skin. Further transcriptomic and morphological examination of these newly established cell models revealed enlarged nuclear and cell body size and a faster growth rate of PSA cells in comparison with either the healthy NTERT or KT2 cell lines, all trademark affiliations of psoriasis. These findings suggest that immortalized psoriatic PSA cells, the first of their kind, faithfully profile the psoriatic phenotype in vitro and may provide a novel tool for interrogating the disease's pathogenic mechanisms.