ERN1 and colitis: Ern1 knockout (KO) in mice directly leads to death during the state of embryonic process (Iwawaki et al., 2009), while Ern2 KO in mice results in increased ER stress, shortened latency of colitis, exacerbated DSS-induced colitis, induced idiopathic colitis (Bertolotti et al., 2001; Kurashima and Kiyono, 2017), and aggravated severity of colitis.