ERN1 and metabolic dysfunction-associated steatotic liver disease: Compared to normal liver tissues, NAFLD tissues have been detected to have higher levels of C/EBP homologous protein (CHOP), cleaved ATF6 and X-box binding protein 1 (XBP1, an mRNA that is spliced by IRE1), indicating that the UPR and ERS are activated in subjects with NAFLD [44].