scholarly journals Effects of Methylmethionine Sulfonium Chloride on Activity and Tight Junction Protein Expression of Intestinal Porcine Jejunum Epithelial Cells (IPEC-J2)

Author(s):  
Jianping Yang ◽  
Xinfeng Li ◽  
Xinlei Wang ◽  
Xin Wen ◽  
Tongtong Zhang ◽  
...  

Background: The intestinal mucosal epithelium acts as a physical and biochemical barrier and plays an important role in regulating of barrier function and immune homeostasis. Methylmethionine sulfonium chloride (MMSC) is a multifaceted amino acid that is critical to the normal physiology of the gastrointestinal tract. The present study investigated the effects of extracellular MMSC on intestinal epithelial cell line (IPEC-J2). Methods: IPEC-J2 cells were treated with 0.1, 0.5 and 1 mM MMSC, respectively for an additional 24 h. CCK-8 assay was used to evaluate cell proliferation. The cell Annexin V-FITC/PI apoptosis were analyzed by flow cytometry (FCM) method. The mRNA transcript and protein expression levels of tight junction proteins in IPEC-J2 cells were detected by real-time quantitative polymerase chain reaction (RT-qPCR) and western blotting (WB). Result: The results showed that MMSC could stimulate IPEC-J2 cells proliferation and inhibit cell apoptosis. In addition, the RT-qPCR and WB results indicated that 0.5 mM MMSC significantly increased the mRNA and protein expression of tight junction proteins, including occludin, claudin-1 and zonula occludin-1 (Zo-1). These findings may provide valuable information to investigate further the possible mechanism and function of MMCS on the intestinal barrier function.

2019 ◽  
Author(s):  
Jingtao Wu ◽  
Caimei He ◽  
Jie Bu ◽  
Yue Luo ◽  
Shuyuan Yang ◽  
...  

Abstract Background: The intestinal epithelial barrier, which works as the first line of defense between the intestinal environment and the parasitifer, once destroyed, it will cause serious inflammation or other intestinal diseases. Tight junctions (TJs) play a vital role to maintain the integrity of the epithelial barrier. Lipopolysaccharide (LPS), one of the most important inflammatory factors will downregulate specific TJ proteins including Occludin and Claudin-1 and impair integrity of the epithelial barrier. Betaine (Bet) has excellent anti-inflammatory activity but whether Bet has any effect on tight junction proteins, particularly on LPS-induced dysfunction of epithelial barriers remains unknown. Intestinal porcine epithelial cells (IPEC-J2) were used as an in vitro model, the purpose of this study is to explore the pharmacological effect of Bet on improving intestinal barrier function represented by TJ proteins.Results: The results demonstrated that Bet enhanced the expression of tight junction proteins while LPS( 1μg /m L)downregulates the expression of these proteins. Furthermore, Bet attenuates LPS-induced decreases of tight junction proteins both shown by WB and RT-PCR. The immunofluorescent images consistently revealed that LPS induced the disruption of tight junction protein Claudin-1 and reduced its expression while Bet could reverse these alterations. Similar protective role of Bet on intestinal barrier function was observed by transepithelial electrical resistance (TEER) approach. Conclusion: In conclusion, our research demonstrated that Bet attenuated LPS-induced downregulation of Occludin and Claudin-1 and restored the intestinal barrier function.


2018 ◽  
Vol 46 (5) ◽  
pp. 1779-1792 ◽  
Author(s):  
Zhiping Xiao ◽  
Lujie Liu ◽  
Wenjing Tao ◽  
Xun Pei ◽  
Geng Wang ◽  
...  

Background/Aims: The intestinal mucosa forms a physical and metabolic barrier against the diffusion of pathogens, toxins, and allergens from the lumen into the circulatory system. Early weaning, a critical phase in swine production, can compromise intestinal barrier function through mucosal damage and alteration of tight junction integrity Maintenance of intestinal barrier function plays a pivotal role in optimum gastrointestinal health. In this study, we investigated the effects of Clostridium tyrobutyricum (C.t) on intestinal barrier dysfunction induced by lipopolysaccharide (LPS) and the underlying mechanisms involved in intestinal barrier protection. Methods: A Transwell model of IPEC-J2 cells was used to imitate the intestinal barrier. Fluorescence microscopy and flow cytometry were used to evaluate apoptosis. Real-time PCR was used to detect apoptosis-related genes and the downstream genes of the p38/c-Jun N-terminal kinase (JNK) signaling pathways. Western blotting was used to measure the expressions of tight junction proteins and mitogen-activated protein kinases. Results: C.t efficiently maintained trans-epithelium electrical resistance values and intestinal permeability after LPS-induced intestinal barrier disruption. The expressions of tight junction proteins (ZO-1, claudin-1, and occludin) were promoted when IPEC-J2 cells were treated with C.t. Fluorescence imaging and flow cytometry revealed that C.t qualitatively and quantitatively inhibited LPS-induced cell apoptosis. C.t also increased the relative expression of the anti-apoptotic gene Bcl-2 and decreased that of the apoptotic genes Bax and caspase-3/-8. Moreover, the protective effect of C.t on damaged intestinal cell models was associated with suppression of p38 and JNK phosphorylation, negative regulation of the relative expressions of downstream genes including AP-1, ATF-2, ELK-1, and p53, and activation of Stat3 expression. Conclusions: These findings indicate that C.t may promote intestinal integrity, suggesting a novel probiotic effect on intestinal barrier function.


Author(s):  
Amit Tripathi ◽  
Maria Grazia Clemente ◽  
Anna Sapone ◽  
Maria Paola Musu ◽  
Stefano De Virgiliis ◽  
...  

2011 ◽  
Vol 106 (6) ◽  
pp. 870-877 ◽  
Author(s):  
Julia B. Ewaschuk ◽  
Gordon K. Murdoch ◽  
Ian R. Johnson ◽  
Karen L. Madsen ◽  
Catherine J. Field

The weaning period is associated with an increased prevalence of gastrointestinal infection in many species. Glutamine (Gln) has been shown to improve intestinal barrier function and immune function in both in vivo and in vitro models. The objective of the present study was to determine the effect of dietary Gln supplementation on intestinal barrier function and intestinal cytokines in a model of Escherichia coli infection. We randomised 21-d-old piglets (n 20) to nutritionally complete isonitrogenous diets with or without Gln (4·4 %, w/w) for 2 weeks. Intestinal loops were isolated from anaesthetised pigs and inoculated with either saline or one of the two E. coli (K88AC or K88 wild-type)-containing solutions. Intestinal tissue was studied for permeability, cytokine expression, fluid secretion and tight-junction protein expression. Animals receiving Gln supplementation had decreased potential difference (PD) and short-circuit current (Isc) in E. coli-inoculated intestinal loops (PD 0·628 (sem 0·151) mV; Isc 13·0 (sem 3·07) μA/cm2) compared with control-fed animals (PD 1·36 (sem 0·227) mV; Isc 22·4 (sem 2·24) μA/cm2). Intestinal tissue from control, but not from Gln-supplemented, animals responded to E. coli with a significant increase in mucosal cytokine mRNA (IL-1β, IL-6, transforming growth factor-β and IL-10). Tight-junction protein expression (claudin-1 and occludin) was reduced with exposure to E. coli in control-fed animals and was not influenced in Gln-supplemented piglets. Gln supplementation may be useful in reducing the severity of weaning-related gastrointestinal infections, by reducing the mucosal cytokine response and altering intestinal barrier function.


2010 ◽  
Vol 298 (5) ◽  
pp. G625-G633 ◽  
Author(s):  
Wei Zhong ◽  
Craig J. McClain ◽  
Matthew Cave ◽  
Y. James Kang ◽  
Zhanxiang Zhou

Disruption of the intestinal barrier is a causal factor in the development of alcoholic endotoxemia and hepatitis. This study was undertaken to determine whether zinc deficiency is related to the deleterious effects of alcohol on the intestinal barrier. Mice were pair fed an alcohol or isocaloric liquid diet for 4 wk, and hepatitis was detected in association with elevated blood endotoxin level. Alcohol exposure significantly increased the permeability of the ileum but did not affect the barrier function of the duodenum or jejunum. Reduction of tight-junction proteins at the ileal epithelium was detected in alcohol-fed mice although alcohol exposure did not cause apparent histopathological changes. Alcohol exposure significantly reduced the ileal zinc concentration in association with accumulation of reactive oxygen species. Caco-2 cell culture demonstrated that alcohol exposure increases the intracellular free zinc because of oxidative stress. Zinc deprivation caused epithelial barrier disruption in association with disassembling of tight junction proteins in the Caco-2 monolayer cells. Furthermore, minor zinc deprivation exaggerated the deleterious effect of alcohol on the epithelial barrier. In conclusion, epithelial barrier dysfunction in the distal small intestine plays an important role in alcohol-induced gut leakiness, and zinc deficiency attributable to oxidative stress may interfere with the intestinal barrier function by a direct action on tight junction proteins or by sensitizing to the effects of alcohol.


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