scholarly journals Lactobacillus reuteri LR1 Improved Expression of Genes of Tight Junction Proteins via the MLCK Pathway in IPEC-1 Cells during Infection with Enterotoxigenic Escherichia coli K88

2018 ◽  
Vol 2018 ◽  
pp. 1-8 ◽  
Author(s):  
Hongbo Yi ◽  
Li Wang ◽  
Yunxia Xiong ◽  
Zhilin Wang ◽  
Yueqin Qiu ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Tight Junction ◽  
Lactobacillus Reuteri ◽  
Transcript Abundance ◽  
Enterotoxigenic Escherichia Coli ◽  
Epithelial Barrier ◽  
Dependent Manner ◽  
Intestinal Epithelial ◽  
Intestinal Epithelial Barrier ◽  
Epithelial Barrier Function

Intestinal epithelial barrier damage disrupts immune homeostasis and leads to many intestinal disorders. Lactobacillus reuteri strains have probiotic functions in their modulation of the microbiota and immune system in intestines. In this study, the effects of L. reuteri LR1, a new strain isolated from the feces of weaning piglets, on intestinal epithelial barrier damage in IPEC-1 cells caused by challenge with enterotoxigenic Escherichia coli (ETEC) K88 were examined. It was found that L. reuteri LR1, in large part, offset the ETEC K88-induced increase in permeability of IPEC-1 cell monolayers and decreased the adhesion and invasion of the coliform in IPEC-1 cells. In addition, L. reuteri LR1 increased transcript abundance and protein contents of tight junction (TJ) proteins zonula occluden-1 (ZO-1) and occludin in ETEC K88-infected IPEC-1 cells, whereas it had no effects on claudin-1 and F-actin expression. Using colloidal gold immunoelectron microscopy, these effects of L. reuteri LR1 on ZO-1 and occludin content in IPEC-1 cells were confirmed. By using ML-7, a selective inhibitor of myosin light-chain kinase (MLCK), the beneficial effect of L. reuteri LR1 on contents of ZO-1 and occludin was shown to be dependent on the MLCK pathway. In conclusion, L. reuteri LR1 had beneficial effects on epithelial barrier function consistent with increasing ZO-1 and occludin expression via a MLCK-dependent manner in IPEC-1 cells during challenge with ETEC K88.

scholarly journals JunD Represses Transcription and Translation of the Tight Junction Protein Zona Occludens-1 Modulating Intestinal Epithelial Barrier Function

2008 ◽  
Vol 19 (9) ◽  
pp. 3701-3712 ◽  
Author(s):  
Jie Chen ◽  
Lan Xiao ◽  
Jaladanki N. Rao ◽  
Tongtong Zou ◽  
Lan Liu ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Tight Junction ◽  
Barrier Function ◽  
Intestinal Epithelial Cells ◽  
Binding Protein ◽  
Mrna Translation ◽  
Epithelial Barrier ◽  
Intestinal Epithelial ◽  
Intestinal Epithelial Barrier ◽  
Epithelial Barrier Function

The AP-1 transcription factor JunD is highly expressed in intestinal epithelial cells, but its exact role in maintaining the integrity of intestinal epithelial barrier remains unknown. The tight junction (TJ) protein zonula occludens (ZO)-1 links the intracellular domain of TJ-transmembrane proteins occludin, claudins, and junctional adhesion molecules to many cytoplasmic proteins and the actin cytoskeleton and is crucial for assembly of the TJ complex. Here, we show that JunD negatively regulates expression of ZO-1 and is implicated in the regulation of intestinal epithelial barrier function. Increased JunD levels by ectopic overexpression of the junD gene or by depleting cellular polyamines repressed ZO-1 expression and increased epithelial paracellular permeability. JunD regulated ZO-1 expression at the levels of transcription and translation. Transcriptional repression of ZO-1 by JunD was mediated through cAMP response element-binding protein-binding site within its proximal region of the ZO-1-promoter, whereas induced JunD inhibited ZO-1 mRNA translation by enhancing the interaction of the ZO-1 3′-untranslated region with RNA-binding protein T cell-restricted intracellular antigen 1-related protein. These results indicate that JunD is a biological suppressor of ZO-1 expression in intestinal epithelial cells and plays a critical role in maintaining epithelial barrier function.

scholarly journals Strain-Dependent Induction of Human Enterocyte Apoptosis byBlastocystisDisrupts Epithelial Barrier and ZO-1 Organization in a Caspase 3- and 9-Dependent Manner

2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
Zhaona Wu ◽  
Haris Mirza ◽  
Joshua D. W. Teo ◽  
Kevin S. W. Tan
Keyword(s):  
Cytoskeletal Proteins ◽  
Epithelial Barrier ◽  
Epithelial Cell Line ◽  
Dependent Manner ◽  
Intestinal Epithelial ◽  
Human Intestine ◽  
Intestinal Epithelial Barrier ◽  
Epithelial Barrier Function ◽  
Enterocyte Apoptosis ◽  
Human Enterocyte

Blastocystisis an emerging protistan parasite colonizing the human intestine. It is frequently reported to cause general intestinal symptoms of vomiting, diarrhea, and abdominal pain. We recently demonstrated thatBlastocystisrearranged cytoskeletal proteins and induced intestinal epithelial barrier compromise. The effect ofBlastocystison enterocyte apoptosis is unknown, and a possible link between microbially induced enterocyte apoptosis and increased epithelial permeability has yet to be determined. The aim of this study is to assess ifBlastocystisinduces human enterocyte apoptosis and whether this effect influences human intestinal epithelial barrier function. Monolayers of polarized human colonic epithelial cell-line Caco-2 were incubated withBlastocystissubtype 7 and subtype 4. Assays for both early and late markers of apoptosis, phosphatidylserine externalization, and nuclear fragmentation, respectively, showed thatBlastocystisST-7, but not ST-4, significantly increased apoptosis in enterocytes, suggesting thatBlastocystisexhibits host specificity and strain-to-strain variation in pathogenicity. ST-7 also activated Caco-2 caspases 3 and 9 but not 8. ST-7 induced changes in epithelial resistance, permeability, and tight junction (ZO-1) localization. Pretreatment of Caco-2 monolayers with a pan-caspase inhibitor z-VAD-fmk significantly inhibited these changes. This suggests a role for enterocyte apoptosis inBlastocystis-mediated epithelial barrier compromise in the human intestine.

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