IL-13 Impairs Tight Junctions in Airway Epithelia

Abstract

Interleukin-13 (IL-13) drives symptoms in asthma with high levels of T-helper type 2 cells (Th2-cells). Since tight junctions (TJ) constitute the epithelial diffusion barrier, we investigated the effect of IL-13 on TJ in human tracheal epithelial cells. We observed that IL-13 increases paracellular permeability, changes claudin expression pattern and induces intracellular aggregation of the TJ proteins zonlua occludens protein 1, as well as claudins. Furthermore, IL-13 treatment increases expression of ubiquitin conjugating E2 enzyme UBE2Z. Co-localization and proximity ligation assays further showed that ubiquitin and the proteasomal marker PSMA5 co-localize with TJ proteins in IL-13 treated cells, showing that TJ proteins are ubiquitinated following IL-13 exposure. UBE2Z upregulation occurs within the first day after IL-13 exposure. Proteasomal aggregation of ubiquitinated TJ proteins starts three days after IL-13 exposure and transepithelial electrical resistance (TEER) decrease follows the time course of TJ-protein aggregation. Inhibition of JAK/STAT signaling abolishes IL-13 induced effects. Our data suggest that that IL-13 induces ubiquitination and proteasomal aggregation of TJ proteins via JAK/STAT dependent expression of UBE2Z, resulting in opening of TJs. This may contribute to barrier disturbances in pulmonary epithelia and lung damage of patients with inflammatory lung diseases.

Avian Influenza A Virus Infects Swine Airway Epithelial Cells without Prior Adaptation

“…The control group received 100 µL of DMEM. For analyses of the JAK/STAT signaling pathway, swine ALI cultures received ALI medium containing 2.5 µM of Ruxolitinib (Invivogen) prior to influenza infection as previously described [ 37 ]. Swine ALI cultures with Ruxolitinib and/or poly (I:C) pre-treatment were infected by avH1N1/06 or swH1N1/06 via apical application as described above.…”

Invited review: human air-liquid-interface organotypic airway tissue models derived from primary tracheobronchial epithelial cells—overview and perspectives

“…This structural resemblance supports the use of ALI cultures as an in vitro system for investigating the TJ-modulating effects of chemicals, such as interleukin-13 (IL-13), cadmium, and CS (Cao et al 2015;Schmidt et al 2019;Tatsuta et al 2019). Schmidt and colleagues reported that IL-13 altered the expression patterns of claudins, induced the colocalization of TJ proteins with proteasomes, and triggered ubiquitination of TJ proteins, eventually leading to degradation and disruption of the junctional complexes (Schmidt et al 2019). Functional epithelial ion channels, such as the sodium channel (ENaC) and CFTR, also are present in ALI airway cultures (Enuka et al 2012;Rayner et al 2019).…”

“…assembled in vivo, the TJ complexes in ALI cultures consist of desmosomes in the subapical regions (Davis et al 2015). This structural resemblance supports the use of ALI cultures as an in vitro system for investigating the TJ-modulating effects of chemicals, such as interleukin-13 (IL-13), cadmium, and CS (Cao et al 2015;Schmidt et al 2019;Tatsuta et al 2019). Schmidt and colleagues reported that IL-13 altered the expression patterns of claudins, induced the colocalization of TJ proteins with proteasomes, and triggered ubiquitination of TJ proteins, eventually leading to degradation and disruption of the junctional complexes (Schmidt et al 2019).…”

Special Issue on “The Tight Junction and Its Proteins: More than Just a Barrier”

“…Cytokines that are secreted not only further stimulate immune cells but also change the regulation and expression of TJ proteins, affecting barrier properties. In airway epithelia, the secretion of interleukin-13 (IL-13) induces the ubiquitination of TJ proteins and leads to proteasomal aggregation via the JAK/STAT-dependent expression of ubiquitin-conjugating E2 enzyme, which finally results in barrier disruption and lung damage [ 4 ]. Immune cells, furthermore, usually balance barrier-disturbing and -protective cytokine secretion; for example, IL-4 inhibits the barrier-enhancing effects of IL-17A, and an imbalance of such cytokine profiles has been shown in atopic dermatitis [ 5 ].…”