scholarly journals Protective Effects of SIRT6 Overexpression against DSS-Induced Colitis in Mice

Cells ◽  
2020 ◽  
Vol 9 (6) ◽  
pp. 1513 ◽  
Author(s):  
Kang Xu ◽  
Yannan Guo ◽  
Lu Ping ◽  
Ying Qiu ◽  
Qingfei Liu ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Tight Junction ◽  
Protective Effect ◽  
Therapeutic Target ◽  
Intestinal Epithelial Cells ◽  
Clinical Manifestations ◽  
Protective Effects ◽  
Intestinal Epithelial

Sirtuin 6 (SIRT6), as a NAD + -dependent deacetylase, plays an indispensable role in the regulation of health and physiology. Loss of SIRT6 causes spontaneous colitis in mice and makes intestinal epithelial cells prone to stress. However, whether SIRT6 overexpression increases resistance to colitis remains unknown. Here, in vivo results demonstrated that SIRT6 overexpression attenuates DSS-induced colitis in terms of clinical manifestations, histopathological damage, loss of tight junction function and imbalanced intestinal microenvironment. Additionally, we also found that the activation of NF-κB and c-Jun induced by DSS is diminished by SIRT6 overexpression. Furthermore, SIRT6 may regulate TAK1 to inhibit NF-κB and c-Jun signaling. Thus, our findings highlight the protective effect of SIRT6 on colon, further supporting the perspective that SIRT6 may be a therapeutic target for intestine injury under stress.

scholarly journals In VitroPrevention ofSalmonellaLipopolysaccharide-Induced Damages in Epithelial Barrier Function by VariousLactobacillusStrains

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Chun-Yan Yeung ◽  
Jen-Shiu Chiang Chiau ◽  
Wai-Tao Chan ◽  
Chun-Bin Jiang ◽  
Mei-Lien Cheng ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Tight Junction ◽  
Mononuclear Cells ◽  
Intestinal Epithelial Cells ◽  
Barrier Properties ◽  
Bacterial Invasion ◽  
Epithelial Barrier ◽  
Intestinal Epithelial ◽  
Peripheral Blood Mononuclear

Background.Lactobacillusshows beneficial anti-inflammatory effects onSalmonellainfection. The maintenance of the tight junction (TJ) integrity plays an importance role in avoiding bacterial invasion. WhetherLactobacilluscould be used to regulate the TJ protein expression and distribution in inflamed intestinal epithelial cells was determined.Methods. Using the transwell coculture model,Salmonellalipopolysaccharide (LPS) was apically added to polarized Caco-2 cells cocultured with peripheral blood mononuclear cells in the basolateral compartment. LPS-stimulated Caco-2 cells were incubated with variousLactobacillusstrains. TJ integrity was determined by measuring transepithelial electrical resistance across Caco-2 monolayer. Expression and localization of TJ proteins (zonula-occludens- (ZO-) 1) were determined by Western blot and immunofluorescence microscopy.Results. Various strains ofLactobacilluswere responsible for the different modulations of cell layer integrity. LPS was specifically able to disrupt epithelial barrier and change the location of ZO-1. Our data demonstrate thatLactobacilluscould attenuate the barrier disruption of intestinal epithelial cells caused bySalmonellaLPS administration. We showed thatLactobacillusstrains are associated with the maintenance of the tight junction integrity and appearance.Conclusion. In this study we provide insight that live probiotics could improve epithelial barrier properties and this may explain the potential mechanism behind their beneficial effectin vivo.

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 Expression of lysophosphatidic acid receptor 5 is necessary for the regulation of intestinal Na+/H+ exchanger 3 by lysophosphatidic acid in vivo

2018 ◽  
Vol 315 (4) ◽  
pp. G433-G442 ◽  
Author(s):  
Kayte A. Jenkin ◽  
Peijian He ◽  
C. Chris Yun
Keyword(s):  
Epithelial Cells ◽  
Lysophosphatidic Acid ◽  
Direct Evidence ◽  
Intestinal Epithelial Cells ◽  
Regulatory Role ◽  
Intestinal Epithelial ◽  
Fluid Absorption ◽  
Wild Type

Lysophosphatidic acid (LPA) is a bioactive lipid molecule, which regulates a broad range of pathophysiological processes. Recent studies have demonstrated that LPA modulates electrolyte flux in the intestine, and its potential as an antidiarrheal agent has been suggested. Of six LPA receptors, LPA5 is highly expressed in the intestine. Recent studies by our group have demonstrated activation of Na+/H+ exchanger 3 (NHE3) by LPA5. However, much of what has been elucidated was achieved using colonic cell lines that were transfected to express LPA5. In the current study, we engineered a mouse that lacks LPA5 in intestinal epithelial cells, Lpar5ΔIEC, and investigated the role of LPA5 in NHE3 regulation and fluid absorption in vivo. The intestine of Lpar5ΔIEC mice appeared morphologically normal, and the stool frequency and fecal water content were unchanged compared with wild-type mice. Basal rates of NHE3 activity and fluid absorption and total NHE3 expression were not changed in Lpar5ΔIEC mice. However, LPA did not activate NHE3 activity or fluid absorption in Lpar5ΔIEC mice, providing direct evidence for the regulatory role of LPA5. NHE3 activation involves trafficking of NHE3 from the terminal web to microvilli, and this mobilization of NHE3 by LPA was abolished in Lpar5ΔIEC mice. Dysregulation of NHE3 was specific to LPA, and insulin and cholera toxin were able to stimulate and inhibit NHE3, respectively, in both wild-type and Lpar5ΔIEC mice. The current study for the first time demonstrates the necessity of LPA5 in LPA-mediated stimulation of NHE3 in vivo. NEW & NOTEWORTHY This study is the first to assess the role of LPA5 in NHE3 regulation and fluid absorption in vivo using a mouse that lacks LPA5 in intestinal epithelial cells, Lpar5ΔIEC. Basal rates of NHE3 activity and fluid absorption, and total NHE3 expression were not changed in Lpar5ΔIEC mice. However, LPA did not activate NHE3 activity or fluid absorption in Lpar5ΔIEC mice, providing direct evidence for the regulatory role of LPA5.

Progastrin1–80stimulates growth of intestinal epithelial cells in vitro via high-affinity binding sites

2003 ◽  
Vol 284 (2) ◽  
pp. G328-G339 ◽  
Author(s):  
P. Singh ◽  
X. Lu ◽  
S. Cobb ◽  
B. T. Miller ◽  
N. Tarasova ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Binding Sites ◽  
Intestinal Epithelial Cells ◽  
Full Length ◽  
Intestinal Epithelial ◽  
Growth Effects ◽  
High Affinity ◽  
Significant Difference

Proliferation and carcinogenesis of the large intestinal epithelial cells (IEC) cells is significantly increased in transgenic mice that overexpress the precursor progastrin (PG) peptide. It is not known if the in vivo growth effects of PG on IEC cells are mediated directly or indirectly. Full-length recombinant human PG (rhPG1–80) was generated to examine possible direct effects of PG on IEC cells. Surprisingly, rhPG (0.1–1.0 nM) was more effective than the completely processed gastrin 17 (G17) peptide as a growth factor. Even though IEC cells did not express CCK1and CCK2receptors (-R), fluorescently labeled G17 and Gly-extended G17 (G-Gly) were specifically bound to the cells, suggesting the presence of binding proteins other than CCK1-R and CCK2-R on IEC cells. High-affinity ( Kd= 0.5–1.0 nM) binding sites for125I-rhPG were discovered on IEC cells that demonstrated relative binding affinity for gastrin-like peptides in the order PG ≥ COOH-terminally extended G17 ≥ G-Gly > G17 > *CCK-8 (* significant difference; P< 0.05). In conclusion, our studies demonstrate for the first time direct growth effects of the full-length precursor peptide on IEC cells in vitro that are apparently mediated by the high-affinity PG binding sites that were discovered on these cells.

Glutamine protects intestinal epithelial cells: role of inducible HSP70

1997 ◽  
Vol 272 (4) ◽  
pp. G879-G884 ◽  
Author(s):  
P. E. Wischmeyer ◽  
M. W. Musch ◽  
M. B. Madonna ◽  
R. Thisted ◽  
E. B. Chang
Keyword(s):  
Epithelial Cells ◽  
Intestinal Epithelial Cells ◽  
Mucosal Healing ◽  
Epithelial Cell Line ◽  
Protective Effects ◽  
Intestinal Epithelial ◽  
Cellular Protection ◽  
Gut Mucosa ◽  
Shock Proteins ◽  
Hsp70 Induction

Glutamine (Gln) protects gut mucosa against injury and promotes mucosal healing. Because the induction of heat shock proteins (HSP) protects cells under conditions of stress, we determined whether Gln conferred protection against stress in an intestinal epithelial cell line through HSP induction. Gln added to IEC-18 cells induces an increase in HSP70, a concentration-dependent effect also seen with mRNA. Two forms of injury, lethal heat (49 degrees C) and oxidant, were used, and viability was determined by 51Cr release. Gln-treated cells were significantly more resistant to injury. Treatment with 6-diazo-5-oxo-L-norleucine (DON), a nonmetabolizable analog of Gln, induced HSP70 and protected cells from injury, but less than Gln. These findings suggest that the effects of Gln on HSP70 induction and cellular protection are mediated by metabolic and nonmetabolic mechanisms. To determine whether HSP induction was central to the action of Gln and DON, quercetin, which blocks HSP induction, was used. Quercetin blocked HSP70 induction and the protective effect of Gln and DON. We conclude that the protective effects of Gln in intestinal epithelial cells are in part mediated by HSP70 induction.

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