Th104 - GPCR19 Agonist (HY209) Regulates P2X7 Ion Channel-mediated NLRP3 Inflammasomal Activation and Ameliorates Atopic Dermatitis in Mice

Atopic dermatitis (AD) is the most common chronic inflammatory skin disorder, characterized by intense itch and recurrent eczematous lesions. Although T helper 2 cell-mediated immune responses are dominant, there is growing evidence showing that AD disorder involves multiple immune pathways. Due to lack of proper therapy, the strategies of T cell modulators in combination with targeting keratinocytes and/or myeloid cells might hold promise for achieving disease control in AD patients better than T cell modulators alone. In this regards, targeting NLRP3 inflammasome (N3I) of keratinocytes and skin-infiltrating/resident myeloid cells might open new insight for AD patient’s therapy. Because of the presence of polymorphisms, subtypes, ubiquitous expression, and redundant pathways, inhibition of N3I components is ineffective for inflammatory disorders. We show that HY209 regulates both priming and activation phases of N3I of keratinocytes. HY209 receptor, GPCR19, colocalizes with P2X7R which enhance Ca⁺⁺ mobilization that leads to N3I activation of keratinocytes. HY209 desensitizes P2X7R, inhibits BzATP-mediated Ca⁺⁺ mobilization and suppresses P2X7R expression in addition to inhibiting NF-kB activation of keratinocytes. Transcription of N3I components, and processing of immature IL-1β and IL-18 were suppressed by HY209 treatment in vitro and in vivo. Topical and oral treatment with HY209 ameliorates pro-inflammatory features of atopic dermatitis in Balb/c mice induced by DNCB and further confirmation using MC903 and oxazolone mice AD models. Considering the effects of HY209 alone on atopic dermatitis, HY209 might improve clinical symptoms of AD patients synergistically when combined with therapeutics targeting pathogenic Th2 cells together.