051 Effective inhibition of Th17/Th22 pathway in in vitro and ex vivo models of psoriasis by Celastrol enriched plant cell culture extract (CEE)

Psoriasis is an immune-mediated inflammatory disease where Th17 pathway is mainly involved. Systemic interventions with biologics to block specifically Th17 pathway are now effective to treat severe psoriasis. However, for efficient topical treatment, small molecule is more suitable than antibody to penetrate and target epidermal keratinocytes, the key players in psoriasis. Celastrol, a well-described triterpene, is present in low amount in Tripterygium wilfordii roots. By plant cell culture we were able to boost Celastrol production in bioreactors. Here, we evaluated immune modulator effect of Celastrol enriched extract (CEE) in Th17 psoriasis induced models in vitro and ex vivo in view of its dermatological usage. In vitro (i) human CD4+ T lymphocytes or (ii) NHEK or (iii) microepidermis were stimulated in the presence of CEE. Selected Th17 cytokines were assessed either by ELISA (hCD4+) or by RT-qPCR (NHEK). In ex vivo, reconstituted human epidermis (RHE) was stimulated in the presence of CEE (30 ng/ml): IL8 was quantified by ELISA. In vitro, CEE dose dependently inhibited expression of induced Th17 cytokines: (i) IL17A, IL22, TNF-alpha, IFN-gamma and IL6 in stimulated hCD4+ T cells; and (ii) most of analyzed genes in stimulated NHEK. Ex vivo, in stimulated RHE, IL8 expression was significantly reduced by CEE at 30ng/ml. These findings showed clearly that CEE inhibited both in vitro and ex vivo models: Th17 cytokines and key inflammatory parameters involved in psoriasis. The data indicated that inflammation and excessive keratinocyte proliferation could be effectively modulated by CEE. Moreover, this high added value CEE was obtained by an ecofriendly bioprocess in contrast to traditional roots obtained extracts. This is the first time, a well-defined immune-modulator CEE is proposed for topical application in psoriasis