Abstract
Background: Thalidomide can be a TNIF-alpha inhibitor for treating skin inflammation. This drug exhibits a strong toxicity that limits its application.
Objective: We synthesized a thalidomide analog containing the benzyl chloride group (2-[1-(3-chlorobenzyl)-2,6-dioxopiperidin-3-yl]isoindoline-1,3-dione, CDI) to examine anti-inflammatory activity against psoriasis.
Methods: The evaluation was conducted by the experimental platforms of in vitro TNIF-alpha- or imiquimod (IMQ)-stimulated HaCaT cells and in vivo IMQ-induced psoriasiform plaque.
Results: Using the in vitro keratinocyte model, we demonstrated a greater inhibition of IL-1 beta, IL-6, and IL-24 by CDI than by thalidomide. No significant cytotoxicity was observed at 100 mu M. CDI delivered facilely into the skin with a cutaneous targeting ability 228-fold greater than thalidomide. CDI caused a negligible irritation on healthy mouse skin. We showed that topically applied CDI reduced IMQ-induced red scaly lesions, hyperplasia, microabscesses, and cytokine expression in the mouse model. The skin-barrier function measured by transepidermal water loss (TEWL) could be partially recovered from 50.6-36.3 g/m(2)/h by CDI. The mechanistic study showed that CDI suppressed cytokine production by inhibiting the phosphorylation of NF-kappa B and AP-1 via MAPK pathways.
Conclusion: CDI would be beneficial for the development of a therapeutic agent against psoriasis. (C) 2020 Published by Elsevier B.V. on behalf of Japanese Society for Investigative Dermatology.