1. LPS-induced epithelial barrier disruption via hyperactivation of CACC and ENaC
- Author
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Guang-Yan Yu, Kyungpyo Park, Xin Cong, Yonghwan Shin, Junchul Kim, Jin Man Kim, Sang Woo Lee, Minkyoung Kim, and Fengjiao Chang
- Subjects
0301 basic medicine ,Epithelial sodium channel ,Lipopolysaccharides ,Male ,LPS ,Lipopolysaccharide ,Physiology ,education ,depolarization-induced tyrosine phosphorylation ,Epithelium ,Permeability ,Sodium Channels ,Membrane Potentials ,Tight Junctions ,Rats, Sprague-Dawley ,03 medical and health sciences ,chemistry.chemical_compound ,0302 clinical medicine ,Chloride Channels ,apical membrane depolarization ,Animals ,Cells, Cultured ,health care economics and organizations ,Tight junction ,Ussing chamber ,urogenital system ,Chemistry ,tyrosine phosphorylation ,Depolarization ,Tyrosine phosphorylation ,Epithelial Cells ,Cell Biology ,epithelial barrier disruption ,Apical membrane ,humanities ,Cell biology ,Rats ,030104 developmental biology ,paracellular permeability ,Paracellular transport ,CACC ,Zonula Occludens-1 Protein ,epithelial barrier ,030217 neurology & neurosurgery - Abstract
Gram-negative bacterial lipopolysaccharide (LPS) increases the susceptibility of cells to pathogenic diseases, including inflammatory diseases and septic syndrome. In our experiments, we examined whether LPS induces epithelial barrier disruption in secretory epithelia and further investigated its underlying mechanism. The activities of Ca2+-activated Cl− channels (CACC) and epithelial Na+ channels (ENaC) were monitored with a short-circuit current using an Ussing chamber. Epithelial membrane integrity was estimated via transepithelial electrical resistance and paracellular permeability assays. We found that the apical application of LPS evoked short-circuit current ( Isc) through the activation of CACC and ENaC. Although LPS disrupted epithelial barrier integrity, this was restored with the inhibition of CACC and ENaC, indicating the role of CACC and ENaC in the regulation of paracellular pathways. We confirmed that LPS, CACC, or ENaC activation evoked apical membrane depolarization. The exposure to a high-K+ buffer increased paracellular permeability. LPS induced the rapid redistribution of zonula occludens-1 (ZO-1) and reduced the expression levels of ZO-1 in tight junctions through apical membrane depolarization and tyrosine phosphorylation. However, the LPS-induced epithelial barrier disruption and degradation of ZO-1 were largely recovered by blocking CACC and ENaC. Furthermore, although LPS-impaired epithelial barrier became vulnerable to secondary bacterial infections, this vulnerability was prevented by inhibiting CACC and ENaC. We concluded that LPS induces the disruption of epithelial barrier integrity through the activation of CACC and ENaC, resulting in apical membrane depolarization and the subsequent tyrosine phosphorylation of ZO-1.
- Published
- 2020
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