Discovery of 5-((1H-indazol-3-yl) methylene)-2-thioxoimidazolidin-4-one derivatives as a new class of AHR agonists with anti-psoriasis activity in a mouse model.

Aryl hydrocarbon receptor (AHR) is a ligand dependent transcription factor and participates in the regulation of the immune balance of Th17/22 and Treg cells. It has been found to be widely expressed in the skin, and involved in the pathology of psoriasis. Therefore, AHR is thought as a potential intervention target for psoriasis. Here, we report the discovery of 5-((1H-indazol-3-yl) methylene)-2-thioxoimidazolidin-4-one derivatives as a new class of AHR agonists. Structure-activity relationship analyses led to the identification of the most active compound, 5- ((1H-indazol-3-yl)methylene) -3- (prop-2-yn-1-yl) -2-thiooimidazolidin-4-one (24e), which exhibited an EC50 value of 0.015 µM against AHR. Mechanism of action studies showed that 24e regulated the expression of CYP1A1 by activating the AHR pathway. Topical administration of 24e substantially alleviated imiquimod (IMQ)-induced psoriasis-like skin lesion. Overall, compound 24e could be a good lead compound for drug discovery against psoriasis, and hence deserving further in-depth studies.