Gastric mucosal surface and mucus glycoproteins (Gastric mucins) (MUC)

Gastric mucosal surface and mucus glycoproteins, primarily consisting of the large gel-forming mucins MUC5AC and MUC6, serve as the first line of defense for the stomach lining against luminal acid and pepsin (NCBI: PMC3735930). MUC5AC is secreted by surface mucous cells and forms the outer layer of the gastric mucus, while MUC6 is produced by gland mucous cells and occupies the deeper layer (UniProt: P35226, Q13010). This glycoprotein matrix creates a stable, viscoelastic gel that traps bicarbonate ions, maintaining a pH gradient that protects the underlying epithelium from autodigestion (StatPearls: NBK551527). In conditions like peptic ulcer disease, gastritis, and Helicobacter pylori infection, the integrity of this glycoprotein barrier is often diminished, making the mucosa vulnerable to injury (PubMed: 10403711). Therapeutic strategies involve cytoprotective agents like sucralfate, which binds to the glycoprotein-rich exudates of ulcers to form a protective plug, and bismuth compounds that coat the mucosal surface (PubChem: CID 636371). Additionally, drugs like misoprostol and rebamipide enhance the gastric defense by stimulating the synthesis and secretion of these glycoproteins, thereby reinforcing the protective barrier (PubChem: CID 4123). These glycoproteins also play a role in modulating the inflammatory response and providing a niche for the gastric microbiota. Understanding the biochemical properties of these mucins is essential for developing targeted therapies that can restore mucosal homeostasis in chronic gastric disorders.

Other names

Gastric mucinsGastric mucus glycoproteinsMUC5ACMUC6Gastric mucus barrier

Cytoprotection through the formation of a physical barrier and the stimulation of endogenous mucus and bicarbonate secretion.