scholarly journals DHA protects against experimental colitis in IL-10-deficient mice associated with the modulation of intestinal epithelial barrier function

2015 ◽  
Vol 114 (2) ◽  
pp. 181-188 ◽  
Author(s):  
Jie Zhao ◽  
Peiliang Shi ◽  
Ye Sun ◽  
Jing Sun ◽  
Jian-Ning Dong ◽  
...  

A defect in the intestinal barrier is one of the characteristics of Crohn's disease (CD). The tight junction (TJ) changes and death of epithelial cells caused by intestinal inflammation play an important role in the development of CD. DHA, a long-chain PUFA, has been shown to be helpful in treating inflammatory bowel disease in experimental models by inhibiting the NF-κB pathway. The present study aimed at investigating the specific effect of DHA on the intestinal barrier function in IL-10-deficient mice. IL-10-deficient mice (IL-10− / −) at 16 weeks of age with established colitis were treated with DHA (i.g. 35·5 mg/kg per d) for 2 weeks. The severity of their colitis, levels of pro-inflammatory cytokines, epithelial gene expression, the distributions of TJ proteins (occludin and zona occludens (ZO)-1), and epithelial apoptosis in the proximal colon were measured at the end of the experiment. DHA treatment attenuated the established colitis and was associated with reduced infiltration of inflammatory cells in the colonic mucosa, lower mean histological scores and decreased levels of pro-inflammatory cytokines (IL-17, TNF-α and interferon-γ). Moreover, enhanced barrier function was observed in the DHA-treated mice that resulted from attenuated colonic permeability, rescued expression and corrected distributions of occludin and ZO-1. The results of the present study indicate that DHA therapy may ameliorate experimental colitis in IL-10− / − mice by improving the intestinal epithelial barrier function.

2020 ◽  
Author(s):  
xing han zheng ◽  
li ting mai ◽  
tong tong wang ◽  
ying xu ◽  
zi ren su ◽  
...  

Abstract Background: Our previous study indicates that Brucea javanica oil (BJO) is beneficial for treatment of ulcerative colitis (UC), and that quassinoids in particular brusatol are bioactive components. However, it is still uncertain whether or not other components in BJO, such as oleic acid and fatty acids, have anti-UC effect.Purpose: The present study aimed to compare the anti-UC effects between brusatol-enriched BJO (BE-BJO) and brusatol-free BJO (BF-BJO), and to explore the effects and mechanisms of BE-BJO on colon inflammation and intestinal epithelial barrier function.Methods: Balb/C mice received 3% (wt/vol) DSS for one weeks to establish the UC model. Different doses of BE-BJO, BF-BJO or BJO were treated. Body weight and colon length were measured. Disease activity index (DAI) and histological analysis were evaluated. The levels of pro-inflammatory cytokines in the colon tissues were measured by enzyme linked immunosorbent assay (ELISA). The expressions of tight junction proteins were tested to investigate the intestinal epithelial barrier function. The effects of BE-BJO on NF-κB and RhoA/ROCK pathways were studied.Results: BE-BJO alleviated DSS-induced loss of body weight, increase of DAI and shortening of colon, whereas BF-BJO did not have these protective effects. BE-BJO treatment improved the morphology of colon tissue, inhibited the production and release of pro-inflammatory cytokines including TNF-α、 IFN-γ、 IL-6 and IL-1β in the colon tissue, as well as reversed the decreased expressions of ZO-1, Occludin, Claudin-1and E-cadherin induced by DSS, but augmented Claudin-2 expression. Mechanistically, BE-BJO repressed phosphorylation of NF-κB subunit p65, suppressed RhoA activation, downregulated ROCK, and prevented phosphorylation of myosin light chain (MLC) in DSS-treated mice.Conclusions: This work demonstrated that BE-BJO could ameliorate DSS-induced UC by preventing colon inflammation and enhancing intestinal epithelial barrier function, probably via suppression of NF-κB and RhoA/ROCK signaling pathways. These findings confirm that quassinoids are active compounds from BJO and suggest the therapeutic potential of quassinoids and BE-BJO in the treatment of UC.


2015 ◽  
Vol 308 (12) ◽  
pp. G981-G993 ◽  
Author(s):  
Juan Antonio Rodríguez-Feo ◽  
Marta Puerto ◽  
Carolina Fernández-Mena ◽  
Cristina Verdejo ◽  
José Manuel Lara ◽  
...  

Inflammatory bowel disease (IBD) is characterized by an impaired intestinal barrier function. We aimed to investigate the role of reticulon-4B (RTN-4B/NOGO-B), a structural protein of the endoplasmic reticulum, in intestinal barrier function and IBD. We used immunohistochemistry, confocal microscopy, real-time PCR, and Western blotting to study tissue distribution and expression levels of RTN-4B/NOGO-B in control and IBD samples from mouse and humans. We also targeted RTN-4B/NOGO-B using siRNAs in cultured human intestinal epithelial cell (IECs). Epithelial barrier permeability was assessed by transepithelial electrical resistance (TEER) measurement. RTN-4B/NOGO-B is expressed in the intestine mainly by IECs. Confocal microscopy revealed a colocalization of RTN-4B, E-cadherin, and polymerized actin fibers in tissue and cultured IECs. RTN-4B mRNA and protein expression were lower in the colon of IL-10−/− compared with wild-type mice. Colocalization of RTN-4B/E-cadherin/actin was reduced in the colon of IL-10−/− mice. Analysis of endoscopic biopsies from IBD patients showed a significant reduction of RTN-4B/NOGO-B expression in inflamed mucosa compared with control. Treatment of IECs with H2O2 reduced TEER values and triggered phosphorylation of RTN-4B in serine 107 residues as well as downregulation of RTN-4B expression. Acute RTN-4B/NOGO-B knockdown by siRNAs resulted in a decreased TEER values and reduction of E-cadherin and α-catenin expression and in the amount of F-actin-rich filaments in IECs. Epithelial RTN-4B/NOGO-B was downregulated in human and experimental IBD. RTN-4B participates in the intestinal epithelial barrier function, most likely via its involvement in E-cadherin, α-catenin expression, and actin cytoskeleton organization at sites of cell-to-cell contacts.


RSC Advances ◽  
2017 ◽  
Vol 7 (5) ◽  
pp. 2594-2605 ◽  
Author(s):  
Wanghui Jing ◽  
Xuejiao Gao ◽  
Beilei Han ◽  
Bin Wei ◽  
Nan Hu ◽  
...  

Mori cortex enhances intestinal epithelial barrier function by up-regulating P-glycoproteinviadirect and gut microbiota-mediated mechanisms.


2010 ◽  
Vol 4 (5) ◽  
pp. 637-651 ◽  
Author(s):  
Susanne A Snoek ◽  
Marleen I Verstege ◽  
Guy E Boeckxstaens ◽  
René M van den Wijngaard ◽  
Wouter J de Jonge

2008 ◽  
Vol 19 (9) ◽  
pp. 3701-3712 ◽  
Author(s):  
Jie Chen ◽  
Lan Xiao ◽  
Jaladanki N. Rao ◽  
Tongtong Zou ◽  
Lan Liu ◽  
...  

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.


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