MUC2 and obesity due to melanocortin 4 receptor deficiency: Impairment of this barrier leads to increased intestinal permeability, facilitating microbial translocation to the portal circulation and liver, thereby exacerbating obesity and metabolic disorders Both high- HFD and high fructose intake disrupt MUC2 expression and secretion, resulting in mucus layer thinning and metabolic deteriorationWhile MUC2 glycosylation plays crucial roles in maintaining barrier function and modulating gut microbiota composition [17,18].