Electrophysiologic Analysis of Tight Junction Size and Charge Selectivity

Shashikanth, Nitesh; Rizzo, Heather E.; Pongkorpsakol, Pawin; Heneghan, John F.; Turner, Jerrold R.

doi:10.1002/cpz1.143

Cited by 10 publications

(8 citation statements)

References 73 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…TNFα can operate as an activator for MLCK, in turn leading to the increased permeability of the paracellular barrier [18]. Regarding a changed TJ barrier function, different routes can be involved, in particular the low-capacity leak and the high-capacity pore pathways [40,41]. The low-capacity leak pathway allows macromolecules to cross the TJ barrier, and is involved when TNFα stimulates MLCK [18].…”

Section: Discussionmentioning

confidence: 99%

Tumor Necrosis Factor Alpha Effects on the Porcine Intestinal Epithelial Barrier Include Enhanced Expression of TNF Receptor 1

Droessler

Cornelius

Markov

et al. 2021

IJMS

View full text Add to dashboard Cite

Tumor necrosis factor alpha (TNFα) has been shown to impair the intestinal barrier, inducing and maintaining inflammatory states of the intestine. The aim of the current study was to analyze functional, molecular and regulatory effects of TNFα in a newly established non-transformed jejunal enterocyte model, namely IPEC-J2 monolayers. Incubation with 1000 U/mL TNFα induced a marked decrease in transepithelial electrical resistance (TEER), and an increase in permeability for the paracellular flux marker [3H]-D-mannitol compared to controls. Immunoblots revealed a significant decrease in tight junction (TJ) proteins occludin, claudin-1 and claudin-3. Moreover, a dose-dependent increase in the TNF receptor (TNFR)-1 was detected, explaining the exponential nature of pro-inflammatory effects, while TNFR-2 remained unchanged. Recovery experiments revealed reversible effects after the removal of the cytokine, excluding apoptosis as a reason for the observed changes. Furthermore, TNFα signaling could be inhibited by the specific myosin light chain kinase (MLCK) blocker ML-7. Results of confocal laser scanning immunofluorescence microscopy were in accordance with all quantitative changes. This study explains the self-enhancing effects of TNFα mediated by MLCK, leading to a differential regulation of TJ proteins resulting in barrier impairment in the intestinal epithelium.

show abstract

Section: Discussionmentioning

confidence: 99%

Tumor Necrosis Factor Alpha Effects on the Porcine Intestinal Epithelial Barrier Include Enhanced Expression of TNF Receptor 1

Droessler

Cornelius

Markov

et al. 2021

IJMS

View full text Add to dashboard Cite

show abstract

“…After equilibration, potential differences were measured before and during application of a 50-μA current. Transepithelial short-circuit current (Isc) and transepithelial resistance (TER) were calculated using Ohm’s law, as previously described (2, 43).…”

Section: Methodsmentioning

confidence: 99%

Distinct steady-state properties and TNF responses of epithelial long myosin light chain kinase (MLCK) splice variants

Chánez-Paredes

Abtahi

Zha

et al. 2022

Preprint

Self Cite

View full text Add to dashboard Cite

Intestinal epithelia express two long MLCK splice variants, MLCK1 and MLCK2. We have previously shown that disruption of inflammation-induced MLCK1 recruitment to the perijunctional actomyosin ring prevents barrier loss and attenuates disease progression. Here we sought to define the domains responsible for distinct MLCK1 and MLCK2 behaviors. Quantitative analysis of human biopsies demonstrated specific increases in MLCK1 expression and perijunctional localization in Crohn's disease. When expressed in cultured intestinal epithelial cells, we found, as expected, that MLCK1 is most concentrated at the perijunctional actomyosin ring. In contrast, MLCK2 is predominantly associated with basal F-actin stress fibers. Immunoglobulin-cell adhesion molecule domain 3 (IgCAM3) must be critical for MLCK1 recruitment, as that domain is incomplete in MLCK2. Consistent with this, truncation mutants consisting of N-terminal IgCAM domains 1-4, without C-terminal catalytic domains, localized similarly to full-length MLCK1 and MLCK2, respectively. Further mutagenesis allowed identification of IgCAM2 and IgCAM3 domains as the minimal region required for MLCK1 recruitment. Although IgCAM3 does not concentrate perijunctionally, it can act as a dominant negative effector that limits steady-state and TNF-induced MLCK1 recruitment and barrier loss. Together, the demonstration of selective MLCK1 upregulation and perijunctional recruitment in Crohn's disease and identification of domains required for perijunctional MLCK1 recruitment provide a conceptual understanding and structural data needed for development of therapeutic means of blocking MLCK1-mediated barrier loss without the toxicity of enzymatic MLCK inhibition.

show abstract

“…The tricellular tight junction proteins tricellulin and angulin 1 might also be important regulators of leak pathway permeability. In vitro studies have shown that deletion of either tricellulin or angulin-1 increases leak pathway permeability [146][147][148] . Similar to tricellulin, siRNAmediated knockdown of the other TAMPs, MARVELD3 (refs.…”

Section: The Leak Pathway In Diseasementioning

confidence: 99%

Paracellular permeability and tight junction regulation in gut health and disease

Horowitz

Chánez-Paredes

Haest

et al. 2023

Nat Rev Gastroenterol Hepatol

156

View full text Add to dashboard Cite

Epithelial tight junctions define the paracellular permeability of the intestinal barrier. Molecules can cross the tight junctions via two distinct size-selective and charge-selective paracellular pathways: the pore pathway and the leak pathway. These can be distinguished by their selectivities and differential regulation by immune cells. However, permeability increases measured in most studies are secondary to epithelial damage, which allows non-selective flux via the unrestricted pathway. Restoration of increased unrestricted pathway permeability requires mucosal healing. By contrast, tight junction barrier loss can be reversed by targeted interventions. Specific approaches are needed to restore pore pathway or leak pathway permeability increases. Recent studies have used preclinical disease models to demonstrate the potential of pore pathway or leak pathway barrier restoration in disease. In this Review, we focus on the two paracellular flux pathways that are dependent on the tight junction. We discuss the latest evidence that highlights tight junction components, structures and regulatory mechanisms, their impact on gut health and disease, and opportunities for therapeutic intervention.

show abstract

Electrophysiologic Analysis of Tight Junction Size and Charge Selectivity

Cited by 10 publications

References 73 publications

Tumor Necrosis Factor Alpha Effects on the Porcine Intestinal Epithelial Barrier Include Enhanced Expression of TNF Receptor 1

Tumor Necrosis Factor Alpha Effects on the Porcine Intestinal Epithelial Barrier Include Enhanced Expression of TNF Receptor 1

Distinct steady-state properties and TNF responses of epithelial long myosin light chain kinase (MLCK) splice variants

Paracellular permeability and tight junction regulation in gut health and disease

Contact Info

Product

Resources

About