BRG1 attenuates colonic inflammation and tumorigenesis through autophagy-dependent oxidative stress sequestration

We report that BRG1, an ATPase subunit of the SWI/SNF chromatin remodeling complex, was required for the homeostatic maintenance of colonic epithelial cells (IECs) to prevent the inflammation and tumorigenesis. Consistent with the reduced BRG1 expression in IBD patients, adult mice with IEC ablation of BRG1 developed spontaneous colitis and exhibited increased susceptibility to mutagen-induced tumor growth. Conversely, BRG1 overexpression protected the mice from DSS-induced epithelial damage and subsequent oncogenesis. Mechanistically, BRG1 emerged as a key regulator that directly governs the transcription of Atg16l1, Ambra1, Atg7 and Wipi2, which are important for autophagosome biogenesis. Thus, defective autophagy in BRG1-deficient IECs resulted in excess reactive oxygen species (ROS), which led to the defects in cellular apoptosis and barrier integrity. Overall design: ChIP assays of two-month-old Brg1F/F and Brg1IEC-AKO IECs were generated by deep sequencing