Intestinal infection with Giardia spp. reduces epithelial barrier function in a myosin light chain kinase–dependent fashion

2002 ◽  
Vol 123 (4) ◽  
pp. 1179-1190 ◽  
Author(s):  
Kevin G.–E. Scott ◽  
Jonathon B. Meddings ◽  
David R. Kirk ◽  
Susan P. Lees–Miller ◽  
André G. Buret
Keyword(s):  
Light Chain ◽  
Barrier Function ◽  
Myosin Light Chain Kinase ◽  
Myosin Light Chain ◽  
Epithelial Barrier ◽  
Intestinal Infection ◽  
Epithelial Barrier Function

Interleukin-18 facilitates neutrophil transmigration via myosin light chain kinase-dependent disruption of occludin, without altering epithelial permeability

2012 ◽  
Vol 302 (3) ◽  
pp. G343-G351 ◽  
Author(s):  
Tamia K. Lapointe ◽  
Andre G. Buret
Keyword(s):  
Light Chain ◽  
Myosin Light Chain Kinase ◽  
Myosin Light Chain ◽  
Structure And Function ◽  
Epithelial Barrier ◽  
Intestinal Epithelial ◽  
Barrier Structure ◽  
Intestinal Epithelial Barrier ◽  
Epithelial Barrier Function ◽  
And Function

Compromised epithelial barrier function and tight junction alterations are hallmarks of a number of gastrointestinal disorders, including inflammatory bowel disease (IBD). Increased levels of IL-18 have been observed in mucosal samples from Crohn's disease and ulcerative colitis patients. Remarkably, several reports have demonstrated that immunological or genetic blockage of IL-18 ameliorates the severity of colitis in multiple in vivo models of IBD. Nevertheless, the effects of IL-18 on intestinal epithelial barrier function remain unclear. We hypothesized that IL-18 could disrupt intestinal epithelial barrier structure and function, thus contributing to tissue damage in the context of IBD. The aims of the present study were to determine the effects of IL-18 on epithelial barrier structure and function and to characterize the mechanisms involved in these modulatory properties. Human colonic epithelial Caco-2 monolayers were coincubated with IL-18 for 24 h and processed for immunocytochemistry, immunoblotting, quantitative PCR, and permeability measurements (transepithelial resistance, FITC-dextran fluxes, and bacterial translocation). Our findings indicate that IL-18 selectively disrupts tight junctional occludin, without affecting the distribution pattern of claudin-4, claudin-5, zonula occludens-1, or E-cadherin. This effect coincided with a significant increase in myosin light chain kinase (MLCK) protein levels and activity. Pharmacological inhibition of MLCK and NF-κB prevented IL-18-induced loss of occludin. Although too subtle to alter paracellular permeability, these fine changes correlated with an MLCK-dependent increase in neutrophil transepithelial migration. In conclusion, our data suggest that IL-18 may potentiate inflammation in the context of IBD by facilitating neutrophil transepithelial migration via MLCK-dependent disruption of tight junctional occludin.

scholarly journals Research on the Protective Effect of MiR-185-3p Mediated by Huangqin-Tang Decoction (HQT) on the Epithelial Barrier Function of Ulcerative Colitis

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Zhou Changlin ◽  
Zou Ying ◽  
Zhang Shuhua ◽  
Jiayang Zeng ◽  
Honggang Chi
Keyword(s):  
Ulcerative Colitis ◽  
Protective Effect ◽  
Light Chain ◽  
Barrier Function ◽  
Myosin Light Chain ◽  
Mucosal Injury ◽  
Epithelial Barrier ◽  
Protective Mechanism ◽  
Intestinal Epithelial ◽  
Epithelial Barrier Function

Introduction. It has been reported that the traditional Chinese medicine Huangqin-Tang decoction (HQT) has a protective effect on the epithelial barrier function of ulcerative colitis, but its mechanism has not been fully clarified. This study intends to explore the protective mechanism of HQT in regulating microRNA (miRNA) for the first time. Methods. Based on the Balb/c mice ulcerative colitis model, the mice were given a gavage of 0.1 mL/10 g HQT every day for 7 days; on the 8th day, the colon of the mice was dissected, the length of the colon for the mice was measured, and the score was given based on this. Analysis of colonic mucosal injury was conducted by hematoxylin-eosin staining. Then, the differential miRNA was screened and sequenced in colon tissue using the HiSeq platform. And the differential miR-185-3p gene was verified by RT-PCR. Finally, the effects of HQT on miR-185-3p, occludin protein expression, and transepithelial electrical resistance (TEER) value were observed in combination with the CaCo2 intestinal epithelial cell model. Results. HQT treatment can alleviate the shortening of colon length and reverse the intestinal mucosal injury. miRNA sequencing of colonic tissue showed that miR-185-3p was significantly downregulated in the model group, while HQT could upregulate miR-185-3p, thereby affecting the myosin light chain kinase (MLCK)/myosin light chain phosphorylation (p-MLC) pathway and leading to increased expression of occludin protein, which ultimately protected the intestinal epithelial barrier function. Conclusion. HQT can protect colon epithelial barrier function by regulating miR-185-3p.

scholarly journals Myosin light chain kinase mediates intestinal barrier dysfunction via occludin endocytosis during anoxia/reoxygenation injury

2016 ◽  
Vol 311 (6) ◽  
pp. C996-C1004 ◽  
Author(s):  
Younggeon Jin ◽  
Anthony T. Blikslager
Keyword(s):  
Tight Junction ◽  
Light Chain ◽  
Barrier Function ◽  
Myosin Light Chain Kinase ◽  
Myosin Light Chain ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Barrier Dysfunction ◽  
Junction Protein ◽  
Mlc Phosphorylation

Intestinal anoxia/reoxygenation (A/R) injury induces loss of barrier function followed by epithelial repair. Myosin light chain kinase (MLCK) has been shown to alter barrier function via regulation of interepithelial tight junctions, but has not been studied in intestinal A/R injury. We hypothesized that A/R injury would disrupt tight junction barrier function via MLCK activation and myosin light chain (MLC) phosphorylation. Caco-2BBe1 monolayers were subjected to anoxia for 2 h followed by reoxygenation in 21% O2, after which barrier function was determined by measuring transepithelial electrical resistance (TER) and FITC-dextran flux. Tight junction proteins and MLCK signaling were assessed by Western blotting, real-time PCR, or immunofluorescence microscopy. The role of MLCK was further investigated with select inhibitors (ML-7 and peptide 18) by using in vitro and ex vivo models. Following A/R injury, there was a significant increase in paracellular permeability compared with control cells, as determined by TER and dextran fluxes ( P < 0.05). The tight junction protein occludin was internalized during A/R injury and relocalized to the region of the tight junction after 4 h of recovery. MLC phosphorylation was significantly increased by A/R injury ( P < 0.05), and treatment with the MLCK inhibitor peptide 18 attenuated the increased epithelial monolayer permeability and occludin endocytosis caused by A/R injury. Application of MLCK inhibitors to ischemia-injured porcine ileal mucosa induced significant increases in TER and reduced mucosal-to-serosal fluxes of3H-labeled mannitol. These data suggest that MLCK-induced occludin endocytosis mediates intestinal epithelial barrier dysfunction during A/R injury. Our results also indicate that MLCK-dependent occludin regulation may be a target for the therapeutic treatment of ischemia/reperfusion injury.

scholarly journals Contributions of Myosin Light Chain Kinase to Regulation of Epithelial Paracellular Permeability and Mucosal Homeostasis

2020 ◽  
Vol 21 (3) ◽  
pp. 993 ◽  
Author(s):  
Wei-Qi He ◽  
Jing Wang ◽  
Jian-Ying Sheng ◽  
Juan-Min Zha ◽  
W. Vallen Graham ◽  
...  
Keyword(s):  
Tight Junction ◽  
Enzymatic Activity ◽  
Small Molecule ◽  
Light Chain ◽  
Barrier Function ◽  
Myosin Light Chain Kinase ◽  
Myosin Light Chain ◽  
Chronic Inflammatory Bowel Disease ◽  
Enzymatic Function ◽  
Mucosal Homeostasis

Intestinal barrier function is required for the maintenance of mucosal homeostasis. Barrier dysfunction is thought to promote progression of both intestinal and systemic diseases. In many cases, this barrier loss reflects increased permeability of the paracellular tight junction as a consequence of myosin light chain kinase (MLCK) activation and myosin II regulatory light chain (MLC) phosphorylation. Although some details about MLCK activation remain to be defined, it is clear that this triggers perijunctional actomyosin ring (PAMR) contraction that leads to molecular reorganization of tight junction structure and composition, including occludin endocytosis. In disease states, this process can be triggered by pro-inflammatory cytokines including tumor necrosis factor-α (TNF), interleukin-1β (IL-1β), and several related molecules. Of these, TNF has been studied in the greatest detail and is known to activate long MLCK transcription, expression, enzymatic activity, and recruitment to the PAMR. Unfortunately, toxicities associated with inhibition of MLCK expression or enzymatic activity make these unsuitable as therapeutic targets. Recent work has, however, identified a small molecule that prevents MLCK1 recruitment to the PAMR without inhibiting enzymatic function. This small molecule, termed Divertin, restores barrier function after TNF-induced barrier loss and prevents disease progression in experimental chronic inflammatory bowel disease.

scholarly journals Myosin light chain kinase in microvascular endothelial barrier function

2010 ◽  
Vol 87 (2) ◽  
pp. 272-280 ◽  
Author(s):  
Q. Shen ◽  
R. R. Rigor ◽  
C. D. Pivetti ◽  
M. H. Wu ◽  
S. Y. Yuan
Keyword(s):  
Light Chain ◽  
Barrier Function ◽  
Myosin Light Chain Kinase ◽  
Myosin Light Chain ◽  
Endothelial Barrier ◽  
Endothelial Barrier Function ◽  
Microvascular Endothelial
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