OCLN and inflammatory bowel disease: Studies have shown that the enhancement of the PERK–-ATF4–CHOP pathway disrupts the intestinal barrier function and leads to increased intestinal permeability, thereby promoting the development of inflammatory bowel disease and other intestinal-related diseases.30,31 The specific manifestations are: (1) affecting tight junction proteins: the PERK–ATF4–CHOP signaling pathway may affect tight junction proteins, e.g., claudin and occludin, thereby disrupting the completeness of the enteric mechanical barrier and increasing the permeability of the intestinal tract.