Activating transcription factor 6 protects against endothelial barrier dysfunction

  • Cell Signal. 2022 Nov;99:110432. doi: 10.1016/j.cellsig.2022.110432.
Khadeja-Tul Kubra  1 ,  Mohammad S Akhter  1 ,  Yogesh Saini  2 ,  Konstantin G Kousoulas  2 ,  Nektarios Barabutis  3
Affiliations
  • 1. School of Basic Pharmaceutical and Toxicological Sciences, College of Pharmacy, University of Louisiana Monroe, Monroe, LA 71201, USA.
  • 2. Department of Pathobiological Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, LA 70803, USA.
  • 3. School of Basic Pharmaceutical and Toxicological Sciences, College of Pharmacy, University of Louisiana Monroe, Monroe, LA 71201, USA. Electronic address: [email protected].
PMID: 35933031 DOI: 10.1016/j.cellsig.2022.110432
Abstract

Background: Endothelial hyperpermeability is associated with sepsis and acute respiratory distress syndrome (ARDS). The identification of molecular pathways involved in barrier dysfunction; may reveal promising therapeutic targets to combat ARDS. Unfolded protein response (UPR) is a highly conserved molecular pathway, which ameliorates endoplasmic reticulum stress. The present work focuses on the effects of ATF6, which is a UPR sensor, in lipopolysaccharides (LPS)-induced endothelial hyperpermeability.

Methods: The in vitro effects of AA147 and Ceapin-A7 in LPS-induced endothelial barrier dysfunction were investigated in bovine pulmonary artery endothelial cells (BPAEC). Small interfering (si) RNA was utilized to "silence" ATF6, and electric cell-substrate impedance sensing (ECIS) measured transendothelial resistance. Fluorescein isothiocyanate (FITC)-dextran assay was utilized to assess paracellular permeability. Protein expression levels were evaluated with Western blotting, and cell viability with MTT assay.

Results: We demonstrated that AA147 prevents LPS-induced barrier disruption by counteracting Cofilin and Myosin light chain 2 (MLC2) activation, as well as VE-Cadherin phosphorylation. Moreover, this ATF6 inducer opposed LPS-triggered decrease in transendothelial resistance (TEER), as well as LPS-induced paracellular hyperpermeability. On the Other hand, ATF6 suppression due to Ceapin-A7 or small interfering RNA exerted the opposite effects, and potentiated LPS-induced endothelial barrier disruption. Moderate concentrations of both ATF6 modulators did not affect cell viability.

Conclusions: ATF6 activation protects against endothelial barrier function, suggesting that this UPR sensor may serve as a therapeutic target for sepsis and ARDS.

Keywords
Endothelium; Inflammation; Unfolded protein response; Vasculature.
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