The pathway of Nrf2 in the protection of intestinal mucosal barrier. (A) Keap1 induces the translocation of Nrf2 from the cytoplasm to the nucleus and activates the expression of a wide array of target genes. As a result, the intestinal oxidative injury decreases. (B) The activation of Nrf2 can inhibits inflammatory pathway and reduces cytokine production. Dissociated Keap1 suppresses the ubiquitination and degradation of IκB, thus inhibiting the activation of NF-κB. (C) The binding of Keap1 to p62 causes the autophagy of ubiquitinated proteins. Keap1 participates in the regulation of the Nrf2-keap1-P62-autophagy pathway as a bridge. These two antioxidant pathways coordinate to maintain intestinal barrier function under different physiological and pathological conditions. (D) The activation of Nrf2 increases the expression of the tight junction proteins ZO-1 and occludin. (E) The activation of Nrf2 induces T cell activation and cytokine production.