Sophoricoside improved Crohn's disease-like colitis by inhibiting intestinal epithelial cell apoptosis through PI3K/AKT signaling

BACKGROUND AND AIMS

Increased apoptosis of intestinal epithelial cells (IECs) is a significant cause of intestinal barrier dysfunction in Crohn's disease (CD). Sophoricoside (SOP) is an isoflavone glycoside known for its anti-apoptotic properties. The aim of this study was to investigate the effects of SOP on mice with CD-like colitis and to understand the underlying mechanisms.

METHODS

Mice treated with 2,4,6-trinitrobenzene sulfonic acid (TNBS) were used to examine the therapeutic effect of SOP on CD-like colitis and intestinal barrier damage. To further explore SOP's impact on IECs apoptosis and intestinal barrier protection, an in vitro colonic organoid apoptosis model induced by TNF-α was utilized. Network pharmacology was employed to predict the relevant pathways and molecular processes associated with SOP in the treatment of CD.

RESULTS

Treatment with SOP significantly improved colitis symptoms in TNBS mice, as demonstrated by reductions in the Disease Activity Index (DAI), weight loss, colon shortening, macroscopic scores, colonic tissue inflammatory scores, and the expression of pro-inflammatory factors. Our experiments confirmed that SOP protects the intestinal barrier by counteracting IECs apoptosis. Additionally, this study established that SOP reduced IECs apoptosis by inhibiting the PI3K/AKT signaling pathway.

CONCLUSIONS

SOP can reduce IECs apoptosis through the inhibition of the PI3K/AKT signaling pathway, thereby protecting the intestinal barrier. This study is the first to illustrate how SOP ameliorates colitis and protects the intestinal barrier, suggesting SOP has potential clinical application in treating CD.

Arsenic exposure induces small intestinal toxicity in mice by barrier damage and inflammation response via activating RhoA/ROCK and TLR4/Myd88/NF-κB signaling pathways

Numerous studies have shown that arsenic (As) is an important hazardous metalloid that is commonly considered to have systemic toxicity. The main pathway of arsenic exposure is oral; however, many of the events that occur during its passage through the gastrointestinal tract are unclear, and there are few reports on the effect of arsenic on small intestinal mucosal barrier. This study aimed to investigate arsenic-induced mucosal barrier damage in the small intestine of mice induced by oral exposure and its potential mechanisms. In the present study, histomorphometric and immunohistochemical analyses showed that arsenic-treated mice exhibited signs of irregularly arranged and atrophied small intestinal villi, reduced villus lengths, inflammatory cells infiltration, along with up-regulated expression of inflammatory factors TNF-α, IL-6 and IL-1β in the small intestine of mice. The myeloperoxidase (MPO) activity was also increased in As-exposed mice. Transmission electron microscopy (TEM) analysis demonstrated that intestinal epithelial tight junctions (TJs) were impaired in the small intestines of mice in As group. In addition, arsenic down-regulated mRNA levels of TJ-related genes (ZO-1, ZO-2, occludin, claudin-1, and claudin-7) and protein levels of ZO-1, occludin and claudin-1 were significantly reduced in arsenic-treated groups, while arsenic also increased levels of TLR4, Myd88, NF-κB, RhoA, and ROCK mRNA and protein expression. In summary, these results indicate that the small intestine toxicity in mice evoked by arsenic was correlated with the activation of TLR4/Myd88/NF-κB and RhoA/ROCK pathways.

miR-185-5p / ATG101 axis alleviated intestinal barrier damage in intestinal ischemia reperfusion through autophagy

Objective

Intestinal ischemia-reperfusion (II/R) is a common pathological injury in clinic, and the systemic inflammatory response it causes will lead to multiple organ damage and functional failure. miR-185-5p has been reported to be a regulator of inflammatory response and autophagy, but whether it participates in the regulation of autophagy in II/R is still unclear. Therefore, we aimed to explore the mechanism of miR-185-5p regulating intestinal barrier injury in (II/R).

Methods

Caco-2 cells was induced by oxygen-glucose deprivation/reoxygenation (OGD/R) to establish II/R model. The superior mesenteric artery of C57BL/6 mice was clamped for 45 min and then subjected to reperfusion for 4 h for the establishment of II/R mice model. miR-185-5p mimic, miR-185-5p inhibitor, pcDNA-autophagy-related 101 (ATG101) were respectively transfected into Caco-2 cells. Real-time quantitative polymerase chain reaction (RT-qPCR) was performed to assess miR-185-5p expression. Western blot detected the level of ATG101 and tight junction-associated proteins ZO1, Occludin, E-cadherin, β-catenin, as well as autophagy markers ATG5, ATG12, LC3Ⅰ/Ⅱ, Beclin1 and SQSTM1. Transepithelial electrical resistance (TEER) values was detected by a resistance meter. FITC-Dextran was performed to measure cell permeability. 5-ethynyl-2'-deoxyuridine (EDU) staining measured cell proliferation. Transmission electron microscope was conducted to observe autophagosomes. Hematoxylin & eosin (H&E) staining observed the damage of mice intestinal. Immunohistochemistry (IHC) measured the percentage of ki67 positive cells. TdT-mediated dUTP nick-end labeling (TUNEL) assay assessed cell apoptosis in intestinal tissues of II/R. Dual-luciferase assay verified the targeting relationship between miR-185-5p and ATG101.Results miR-185-5p was overexpressed in OGD/R-induced Caco-2 cells and intestinal tissues of II/R mice. Knocking down miR-185-5p markedly promoted autophagy and TEER values, reduced cell permeability, and alleviated intestinal barrier damage. ATG101 was a target of miR-185-5p, and overexpression of ATG101 promoted autophagy and dampened OGD/R-induced intestinal barrier damage. Overexpression of miR-185-5p reversed the effect of overexpressed ATG101 on OGD/R-induced Caco-2 cells.

Conclusion

Knockdown of miR-185-5p enhanced autophagy and alleviated II/R intestinal barrier damage by targeting ATG101.

Combination of sodium butyrate and probiotics ameliorates severe burn-induced intestinal injury by inhibiting oxidative stress and inflammatory response

Burns are a common traumatic injuries with considerable morbidity and mortality rates. Post-burn intestinal injuries are closely related to oxidative stress and inflammatory response. The aim of the current study was to investigate the combined effect of sodium butyrate (NaB) and probiotics (PROB) on severe burn-induced oxidative stress and inflammatory response and the underlying mechanism of action. Sprague-Dawley rats with severe burns were treated with NaB with or without PROB. Pathomorphology of skin and small intestine tissue was observed using hematoxylin and eosin staining and severe burn-induced apoptosis in small intestine tissue was examined via terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling assay. The release of factors related to inflammation was quantified using ELISA kits and qRT-PCR and levels of oxidative stress markers were evaluated using biochemical assays. Furthermore, mitochondrial morphological changes in small intestinal epithelial cells were observed using transmission electron microscopy. In addition, the underlying mechanism associated with the combined effect of NaB and PROB on severe burn-induced oxidative stress and inflammatory response was investigated using western blotting. The combination of NaB and PROB exerted protective effects against severe burn-induced intestinal barrier injury by reducing the levels of diamine oxidase and intestinal fatty acid binding protein. Combined NaB and PROB treatment inhibited severe burn-induced oxidative stress by increasing superoxide dismutase levels and decreasing those of malondialdehyde and myeloperoxidase levels. Severe burn-induced inflammation was suppressed by combined NaB and PROB administration, as demonstrated by the decreased mRNA expression of tumor necrosis factor-α, interleukin-6, interleukin-1β, and high mobility group box-1 in the small intestine. In addition, this study showed that combined NaB and PROB administration increased nuclear factor-erythroid 2-related factor 2 (Nrf2) protein expression and decreased the phosphorylation of nuclear factor (NF)-κB and extracellular signal-regulated kinase 1/2 (ERK 1/2). In conclusion, our findings indicate that combined NaB and PROB treatment may inhibit severe burn-induced inflammation and oxidative stress in the small intestine by regulating HMGB1/NF-κB and ERK1/2/Nrf2 signaling, thereby providing a new therapeutic strategy for intestinal injury induced by severe burn.