NFE2L2 and colitis: Interestingly, in the same year, Li et al. found that high expression of Nrf2 and HO-1 were correlated with the level of mitogen-activated protein kinase phosphatase-1 (Mkp-1), not only in the colon of mice with DSS-induced colitis but even in colorectal biopsies of patients affected by UC and CD.