Tight junctions in pulmonary epithelia during lung inflammation

Abstract

Inflammatory lung diseases like asthma bronchiale, chronic obstructive pulmonary disease and allergic airway inflammation are widespread public diseases that constitute an enormous burden to the health systems. Mainly classified as inflammatory diseases, the treatment focuses on strategies interfering with local inflammatory responses by the immune system. Inflammatory lung diseases predispose patients to severe lung failures like alveolar oedema, respiratory distress syndrome and acute lung injury. These life-threatening syndromes are caused by increased permeability of the alveolar and airway epithelium and exudate formation. However, the mechanism underlying epithelium barrier breakdown in the lung during inflammation is elusive. This review emphasises the role of the tight junction of the airway epithelium as the predominating structure conferring epithelial tightness and preventing exudate formation and the impact of inflammatory perturbations on their function.

Zinc and respiratory tract infections: Perspectives for COVID‑19 (Review)

“…generally, zinc was shown to be essential for respiratory epithelium due to antioxidant and anti-inflammatory activity (57), as well as regulation of tight junction proteins ZO-1 and claudin-1 (58), thus increasing its barrier functions. In turn, downregulation of tight junction protein complexes e.g., ZO-1 and claudin-1 and reduction in barrier function aggravates viral and bacterial inflammatory processes (59). In addition, loss of TJ perm selectivity in the airways results in an un-controlled leakage of high molecular weight proteins and water into the airways, which results in the formation of alveolar edema and ARdS (60).…”

Respiratory Barrier as a Safeguard and Regulator of Defense Against Influenza A Virus and Streptococcus pneumoniae

“…Three main transmembrane proteins [occludins, claudins, and junctional adhesion molecules (JAM)] are responsible for tightly sealing membranes of adjacent cells within the TJs. Peripheral membrane protein, zonula occludin (ZO), binds to these transmembrane proteins of the TJs to stabilize them in the cytoskeleton and mediate signaling (21)(22)(23). IAV infection disrupts the epithelial barrier by causing reduced expression of occludin, claudin-4, and JAM soon after infection (24).…”

Collagen sponge scaffolds containing growth factors for the functional regeneration of tracheal epithelium

“…Asterisks indicate significant differences (p < 0.05). bFGF: basic fibroblast growth factor; EGF: epidermal growth factor [Colour figure can be viewed at wileyonlinelibrary.com] epithelia (Baker & Baines, 2017;Wittekindt, 2017). In our immunohistological analyses, epithelia in control, IGF-1, and HGF groups had disorganized distributions of TJ components, compared with those in EGF and bFGF-treated tracheal grafts at 1 week after surgery.…”

“…Epithelial barriers are first lines of defence against inhaled microorganisms entering the body, and the barrier function of the epithelium depends on TJ (Turner, ; Wittekindt, ). Normal airway epithelia are covered with airway surface liquids (ASLs) that trap large materials including bacteria, compositions and fluidities of ASLs are influenced by TJs, which restrict exchanges of ions and glucose across epithelia (Baker & Baines, ; Wittekindt, ). In our immunohistological analyses, epithelia in control, IGF‐1, and HGF groups had disorganized distributions of TJ components, compared with those in EGF and bFGF‐treated tracheal grafts at 1 week after surgery.…”

“…Epithelial barriers are first lines of defence against inhaled microorganisms entering the body, and the barrier function of the epithelium depends on TJ (Turner, 2009;Wittekindt, 2017). Normal airway epithelia are covered with airway surface liquids (ASLs) that trap large materials including bacteria, compositions and fluidities of ASLs are influenced by TJs, which restrict exchanges of ions and glucose across FIGURE 6 Mucociliary transport function in control groups and groups treated with 10 μg/ml of bFGF and EGF.…”