RT Journal Article
SR Electronic
T1 Ion transport mechanisms for smoke inhalation injured airway epithelial barrier
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 2020.03.25.007807
DO 10.1101/2020.03.25.007807
A1 Jianjun Chang
A1 Zaixing Chen
A1 Runzhen Zhao
A1 Hong-Guang Nie
A1 Hong-Long Ji
YR 2020
UL http://biorxiv.org/content/early/2020/03/25/2020.03.25.007807.abstract
AB Smoke inhalation injury is the leading cause of death in firefighters and victims. Inhaled hot air and toxic smoke are the predominant hazards to the respiratory epithelium. We aimed to analyze the effects of thermal stress and smoke aldehyde on the permeability of the airway epithelial barrier. Transepithelial resistance (RTE) and the short-circuit currents (ISC) of primary mouse tracheal epithelial (MTE) monolayers were digitized by an Ussing chamber setup. Zonula occludens (ZO)-1 tight junction protein was visualized under confocal microscopy. A cell viability test and fluorescein isothiocyanate-dextran assay were performed. Thermal stress (40°C) decreased RTE in a two-phase manner. Meanwhile, thermal stress increased ISC followed by its decline. Na+ depletion, amiloride (inhibitor for epithelial Na+ channels [ENaCs]), ouabain (blocker for Na+/K+-ATPase) and CFTRinh-172 (blocker of cystic fibrosis transmembrane regulator [CFTR]) altered the responses of RTE and ISC to thermal stress. Steady state 40°C increased activity of ENaCs, Na+/K+-ATPase, and CFTR. Acrolein, which is one of the main oxidative unsaturated aldehydes in fire smoke, eliminated RTE and ISC. Na+ depletion, amiloride, ouabain, and CFTRinh-172 suppressed acrolein-sensitive ISC, but showed activating effects on acrolein-sensitive RTE. Thermal stress or acrolein disrupted ZO-1 tight junctions, increased fluorescein isothiocyanate-dextran permeability but failed to cause cell death and detachment in MTE monolayers. The synergistic effect of thermal stress and acrolein exacerbated the damage to MTE monolayers. In conclusion, the paracellular pathway mediated by the tight junctions and the transcellular pathway mediated by ion channels and transporters contribute to impairing the airway epithelial barrier caused by thermal stress and acrolein.ENaCsepithelial Na+ channelsCFTRcystic fibrosis transmembrane regulatorRTEtransepithelial resistanceISCshort-circuit currentMTEmouse tracheal epithelialFITCfluorescein isothiocyanateHBEhuman bronchial epithelialDMSOdimethyl sulfoxideZO-1zonula occludens-1P1phase 1P2phase 2ASIamiloride-sensitive ISCKCsK+ channelsROSreactive oxygen speciesCaCCsCa2+-activated Cl− channelsNKCCNa+/K+/2Cl−MAPKmitogen-activated protein kinase.