TJP1 and metabolic dysfunction-associated steatotic liver disease: Sun et al. [105] found that an insoluble polysaccharide WIP in the sclerotia of Poria cocos could significantly increase the content of butyric acid in the feces of NAFLD mice, and butyrate could stimulate the release of mucin and increase the ileal mucosal integrity protein (Muc-5) and the transcriptional expression of tight junction proteins (ZO-1 and occludin) and maintain the integrity of the intestinal barrier, thereby ensuring normal intestinal barrier function and preventing harmful bacteria from entering the liver through the intestinal barrier to cause NAFLD.