A Novel Pharmacological Approach to Enhance the Integrity and Accelerate Restitution of the Intestinal Epithelial Barrier

Abstract

Background Disruption of the gut barrier is an essential mechanism of inflammatory bowel diseases (IBDs) contributing to the development of mucosal inflammation. A hallmark of barrier disruption is the disassembly of epithelial adherens junctions (AJs) driven by decreased expression of a major AJ protein, E-cadherin. A group of isoxazole compounds, such as E-cadherin-upregulator (ECU) and ML327, were previously shown to stimulate E-cadherin expression in poorly differentiated human cancer cells. This study was designed to examine whether these isoxazole compounds can enhance and protect model intestinal epithelial barriers in vitro. Methods The study was conducted using T84, SK-CO15, and HT-29 human colonic epithelial cell monolayers. Disruption of the epithelial barrier was induced by pro-inflammatory cytokines, tumor necrosis factor-α, and interferon-γ. Barrier integrity and epithelial junction assembly was examined using different permeability assays, immunofluorescence labeling, and confocal microscopy. Epithelial restitution was analyzed using a scratch wound healing assay. Results E-cadherin-upregulator and ML327 treatment of intestinal epithelial cell monolayers resulted in several barrier-protective effects, including reduced steady-state epithelial permeability, inhibition of cytokine-induced barrier disruption and junction disassembly, and acceleration of epithelial wound healing. Surprisingly, these effects were not due to upregulation of E-cadherin expression but were mediated by multiple mechanisms including inhibition of junction protein endocytosis, attenuation of cytokine-induced apoptosis, and activation of promigratory Src and AKT signaling. Conclusions Our data highlight ECU and ML327 as promising compounds for developing new therapeutic strategies to protect the integrity and accelerate the restitution of the intestinal epithelial barrier in IBD and other inflammatory disorders.

P-Cadherin Regulates Intestinal Epithelial Cell Migration and Mucosal Repair, but Is Dispensable for Colitis Associated Colon Cancer

“…A gain-of-function approach was used to compliment the results obtained with P-cadherin knockout. This approach involved overexpression of P-cadherin in SW620 cells (Figure S5A), which have very low endogenous expression of this adhesion protein [68]. In good agreement with the loss-of-function data, overexpression of P-cadherin did not affect cell proliferation (Figure S5B), but significantly increased SW620 cell adhesion to the collagen I matrix (Figure S5C,D) and inhibited cell spreading (Figure S5E,F).…”

Coactosin-like protein 1 regulates integrity and repair of model intestinal epithelial barriers via actin binding dependent and independent mechanisms

“…To examine the functional role of this actin regulator at epithelial junctions, we used RNA interference to downregulate COTL1 expression in DLD-1 and SK-CO15 cells. These cell lines rapidly establish tight paracellular barriers and were previously used to study the regulation of junctional assembly and remodeling ( Hollande et al, 2003 ; Fujiwara et al, 2015 ; Lechuga et al, 2015 ; Cao et al, 2020 ; Indra et al, 2021 ; Lechuga et al, 2022 ). To select efficient siRNAs for the functional studies, IEC were transfected with four different COTL1 siRNA duplexes.…”

Artemisinin analog SM934 alleviates epithelial barrier dysfunction via inhibiting apoptosis and caspase-1-mediated pyroptosis in experimental colitis

“…To further explore whether SM934 protected the intestinal barrier and inhibited apoptosis directly acting on colonic epithelial cells, the study was conducted using human colonic epithelial cell lines Caco-2 and HT-29 cells exposed to TNF-α, which is commonly known to initiate epithelial barrier damage and apoptosis in IECs, which mimic this progression in vitro ( Bruewer et al, 2003 ; Cao et al, 2020 ; Woznicki et al, 2020 ). Therefore, we constituted the Caco-2 cell monolayer model to evaluate the effect of SM934 on barrier function by measuring the TEER values and intestinal permeability.…”