Intestinal epithelial tight junction barrier (TJ barrier)

The intestinal epithelial tight junction (TJ) barrier is a multi-protein complex that forms a continuous seal between adjacent epithelial cells, serving as the primary determinant of the paracellular pathway (Lee, 2015, PMID: 25624813). It is composed of transmembrane proteins such as claudins, occludin, and junctional adhesion molecules (JAMs), which interact with cytosolic scaffold proteins like zonula occludens (ZO-1) to link the junction to the actin cytoskeleton (Zuo et al., 2020, PMID: 32451518). This barrier is essential for maintaining homeostasis by allowing the selective absorption of nutrients and water while excluding harmful pathogens and environmental antigens (Chelakkot et al., 2018, PMID: 30013308). Impairment of TJ integrity, often referred to as leaky gut, is implicated in the pathogenesis of various conditions, including celiac disease, inflammatory bowel disease (IBD), and metabolic disorders (Fasano, 2020, PMID: 32060130). Therapeutic interventions target this barrier by modulating signaling pathways that regulate TJ assembly, such as the zonulin pathway, or by directly upregulating the expression of pore-sealing claudins (Gopalakrishnan et al., 2012, PMID: 22424437). For instance, larazotide acetate acts as a zonulin antagonist to prevent the disassembly of tight junctions in patients with celiac disease (Schoultz and Keita, 2020, PMID: 32143341).

Other names

Paracellular barrierIntestinal mucosal barrierApical junctional complexTight junction complex

Modulation of tight junction protein assembly and expression, inhibition of zonulin-mediated pathway, and stabilization of the perijunctional actin-myosin ring.