RORα is crucial for attenuated inflammatory response to maintain intestinal homeostasis.

A member of the nuclear receptors, retinoic acid-related orphan receptor a (RORa) is an important transcription factor for various biological processes including circadian rhythm, metabolic regulation, immune cell development and cancer. Here we found that RORa is important for intestinal homeostasis by negatively regulating the transcriptional activity of NF-kB, a major inflammatory regulator in intestinal epithelial cells. Intestinal Rora-deficient mice found were highly susceptible to DSS-induced injury. Transcriptome analysis showed that intestine-specific Rora deletion causes regulatory impairment of NF-kB signaling leading to excessive inflammatory responses. RORa specifically binds to the NF-kB target promoter and inhibits transcriptional activity for transcriptional repression of NF-kB activity via histone deacetylase 3 (HDAC3). Taken together, RORa plays a pivotal role in the homeostatic regulation of intestinal epithelial cells in inflammatory conditions. Therefore, therapeutic strategies designed to modulate RORa activity may be beneficial in the treatment of chronic inflammatory diseases such as Inflammatory bowel disease (IBD). Gene expression profiling of RORaf/f and intestine-specific Rora knock-out (RORaΔIEC) Intestinal Ephithelial Cell (IEC) untreated or treated with DSS.