GSTM1 and colitis: Khor and colleagues demonstrated that DSS-induced colitis is associated with an increased expression of Nrf2 regulatory enzymes (e.g., HO-1, NQO1, UGT1A1, and GSTM1), so the increased susceptibility of Nrf2-deficient mice to DSS-induced colitis may be due to the decreased expression of antioxidant and phase II detoxification enzymes, such as HO-1, along with the increased expression of proinflammatory mediators [87].