Jmjd3 regulates inflammasome activation and aggravates DSS-induced colitis in mice

The intracellular NOD-like receptor nucleotide-binding domain-like receptors Family Pyrin Domain Containing 3 (NLRP3) is a pivotal regulator of intestinal homeostasis through regulating a variety of inflammatory and autoimmune diseases. The Jumonji domain-containing 3 (Jmjd3) plays important role in inflammatory responses and thus has been proposed as a novel attractive epigenetic target for the treatment of inflammatory diseases. We here investigated whether targeting Jmjd3 regulates NLRP3 inflammasome during experimental colitis. Jmjd3 specific inhibitor GSK J4 or knocking down Jmjd3 significantly inhibited NLRP3 inflammasome activation in lipopolysaccharide (LPS) and nigericin-stimulated bone marrow-derived macrophages. Chromatin immunoprecipitation-PCR analysis validated that GSK J4 rescued the decreased repressive H3K27me3 recruitment level on the promotors of nuclear factor-erythroid 2-related factor 2 (Nrf2) in LPS plus nigericin-induced macrophages. Nrf2 knockdown abolished NLRP3 inflammasome activation. Notably, oral administration of GSK J4 attenuated the disease progression in dextran sodium sulfate-induced colitis mouse model, including reduced disease activity index, improved body weight, rescued bowel shortening and NLRP3 inflammasome activation. Overall, our study reveals that Jmjd3 is a potential epigenetic regulator for the treatment of inflammatory bowel disease (IBD), suggesting that Nrf2 is a potential target gene of Jmjd3 by mediating methylation status of trimethylated H3 lysine 27 (H3K27me3) in the promotor and is required for NLRP3 inflammasome activation, thereby providing the platform for potential future therapeutic interventions in IBD.