Epidermal tight junction (TJ) (TJ)

Epidermal tight junctions (TJs) are specialized cell-cell adhesion complexes located primarily in the stratum granulosum of the epidermis, where they form a critical paracellular barrier (Kubo et al., 2009, PMID: 19172026). These structures are composed of transmembrane proteins such as claudins (notably Claudin-1), occludin, and tricellulin, which are anchored to the cytoskeleton by scaffolding proteins like zonula occludens-1 (ZO-1) (Tokumasu et al., 2016, PMID: 27164494). The primary biological function of epidermal TJs is to regulate the movement of water, ions, and solutes, thereby preventing transepidermal water loss and protecting against environmental insults (StatPearls, 2023). In inflammatory conditions like atopic dermatitis, the expression of TJ proteins is significantly reduced, often driven by Th2 cytokines like IL-4 and IL-13, leading to barrier dysfunction (De Benedetto et al., 2011, PMID: 21085110). Therapeutic interventions such as JAK inhibitors (e.g., Upadacitinib) and biologics (e.g., Dupilumab) aim to restore the integrity of these junctions by suppressing inflammatory pathways that downregulate TJ components (Bissonnette et al., 2021, PMID: 33582250).

Other names

Skin barrier structuresZonula occludensStratum granulosum tight junctionsParacellular barrier

Restoration of the skin barrier through the upregulation of tight junction proteins (e.g., Claudin-1, ZO-1) by inhibiting pro-inflammatory cytokines or signaling pathways (e.g., JAK/STAT) that suppress their expression (De Benedetto et al., 2011, PMID: 21085110).