Intestinal epithelial mucus and cell-surface glycoconjugates

The intestinal epithelial mucus and cell-surface glycoconjugates form a critical, multi-component barrier that separates the luminal contents from the underlying intestinal epithelium. This system consists of a thick, viscoelastic mucus layer, primarily composed of the gel-forming mucin MUC2, and an underlying glycocalyx made of membrane-bound mucins (e.g., MUC1, MUC3, MUC17) and various glycoconjugates [UniProt P17068, PMID: 22245968]. Its primary biological functions include providing physical lubrication, acting as a selective sieve for nutrients, and serving as a first line of defense against pathogens and toxins [PMID: 21842163]. In pathological states like ulcerative colitis or Crohn's disease, the mucus layer is often depleted or biochemically altered, leading to increased mucosal permeability and chronic inflammation [PMID: 22245968]. Pharmacologically, this system is targeted by mucoprotective agents like rebamipide, which stimulates mucin production, and by mucoadhesive polymers used in drug delivery to enhance the bioavailability of oral medications [PMID: 25311079, PMID: 21842163]. Additionally, certain pathogens exploit these glycoconjugates as attachment sites to initiate infection, making the modulation of glycan-binding a potential therapeutic strategy. Understanding the composition and dynamics of these glycoconjugates is essential for developing therapies that restore gut barrier integrity or improve targeted drug delivery to the gastrointestinal tract.

Other names

Intestinal mucus barrierIntestinal glycocalyxMucin layerEnterocyte surface glycansMucus-glycocalyx complex

Enhancement of mucin synthesis and secretion, physical coating of the mucosal surface to provide a protective shield, or mucoadhesive binding to prolong drug contact time with the epithelium.