Protection Of Intestinal Barrier Research Articles

Evaluation of glycyrrhetinic acid in attenuating adverse effects of a high-fat diet in largemouth bass (Micropterus salmoides)

Glycyrrhetinic acid (GA) has been shown to promote growth characteristics and play a crucial role in anti-inflammatory responses in animals. To investigate the effects of dietary GA supplementation on growth performance, intestinal inflammation, and intestinal barrier protection in largemouth bass (Micropterus salmoides) fed a high-fat diet (HFD), a 77-day feeding experiment was conducted. A total of 750 largemouth bass, initially averaging 17.39 ± 0.09 g in body weight, were randomly allocated to five experimental groups and fed a control diet, a HFD, and the HFD diet supplemented with GA at either 0.5, 1.0, or 1.5 mg/kg, named as control, HDF, HFD+GA 0.5, HFD+GA 1.0, and 1.5 HFD+GA 1.5, respectively. Each group contained three replicates. The study revealed that dietary GA improved final body weight (P < 0.001), percent weight gain (P = 0.041), and feed intake (P < 0.001), all of which had been affected by a HFD in largemouth bass (P < 0.05). Supplementation of HFD with 1.0 mg/kg GA increased the mRNA expressions and protein levels of corresponding tight junctions, occludin, zonula occluden-1 (ZO-1) and claudin-1 in the intestines of largemouth bass. Furthermore, the addition of HFD with both of 0.5 and 1.0 mg/kg GA decreased the mRNA expressions of pro-inflammatory genes such as interleukin-1β (IL-1β), IL-18, and cysteinyl aspartate specific proteinase 1 (caspase-1), as well as proteins associated with pyroptosis-induced inflammation, including NOD-like receptor family and pyrin domain contain 3 (NLRP3), apoptosis-associated speck-like protein containing a C-terminal caspase recruitment domain (ASC), gasdermin E (GSDME), and N-terminal domain of GSDME (GSDME-N) (P < 0.05). Finally, dietary GA supplementation alleviated mitochondrial damage and reduced reactive oxygen species (ROS) production induced by the HFD. It is concluded that GA supplementation in HFD enhances growth performance, increases mRNA expression and protein levels of tight junction-related parameters, decreases mRNA expression and protein levels of pyroptosis-related genes, and alleviates intestinal mitochondrial injury and inflammation induced by HFD.

Artemisia argyi polysaccharide alleviates osmotic diarrhea by enhancing intestinal barrier protection and anti-inflammation

Artemisia argyi polysaccharide (AAP) is a homogeneous polysaccharide with a molecular weight of 16 kDa, displaying anti-inflammatory, antioxidant, and anti-tumorigenic properties, and potential protective effects on intestinal barrier function. It is anticipated to serve as an efficient component in diarrhea treatment. This study aims to examine the impact of AAP on diarrhea severity, intestinal barrier function, and inflammation in diarrhea-induced rats. The results demonstrated that AAP treatment notably decreased the incidence of diarrhea, reduced its severity, and lowered the disease activity score in rats, while also increasing body weight. Oral administration of AAP augmented goblet cell counts and elevated mucin-2 expression, aiding in the restoration of the mucus barrier. Additionally, AAP treatment enhanced colonic microbial diversity by increasing the abundance of S24–7 and Lactobacillus, while decreasing the levels of Bacteroides, Clostridium, and Sutterella. Moreover, the AAP administration elevated the levels of steroid hormones, prostaglandins, and their derivatives. By inhibiting the TLR4/MyD88/NF-κB pathway, AAP mitigated the release of pro-inflammatory cytokines (IL-1β, IL-6, and TNF-α) and increased the secretion of anti-inflammatory factor (IL-10). Overall, oral AAP administration effectively combats osmotic diarrhea by fortifying mucus barrier integrity and exerting anti-inflammatory effects, suggesting its potential use as an adjunctive agent in oral rehydration therapy.

Exploring the therapeutic potential of Xiangsha Liujunzi Wan in Crohn's disease: from network pharmacology approach to experimental validation

Ethnopharmacological relevanceXiangsha Liujunzi Wan (LJZW) is a traditional Chinese medicine (TCM) formula containing a variety of traditional Chinese herb components. Its principal components are often used in the treatment of gastrointestinal diseases and contribute to the treatment of Crohn's disease (CD). Aim of the studyTo explore the therapeutic potential of LJZW in CD through network pharmacology, bioinformatics, molecular docking, and experimental verification. MethodsThe principal bioactive components and corresponding targets of LJZW were ascertained from the Traditional Chinese Medicine Systems Pharmacology Database and Analysis Platform (TCMSP). Potential targets for CD were identified in GeneCards, OMIM, DrugBank, DisGeNET, CTD, and Gene Expression Omnibus (GEO) databases. Intersection targets of LJZW and CD were identified using a Venn diagram and visualized using Cytoscape 3.8.0 to construct a protein-protein interaction (PPI) network. Gene Ontology (GO) and the Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses were employed to assess the function of intersection targets. AutoDockTools and PyMOL were used for molecular docking to recognize the association between the core ingredients of LJZW and the core targets of CD. Subsequently, a series of experiments were conducted for validation. ResultsThe network pharmacology results indicated that there were 156 bioactive components and 268 corresponding targets for LJZW, 3023 primary relevant targets for CD, and 169 intersection targets for LJZW and CD. The PPI network was employed to identify five hub genes and six clusters. The GO functional analysis indicated that intersection targets are primarily correlated with oxidative stress and inflammatory responses. KEGG pathway analysis revealed that these targets were primarily associated with the phosphotylinosital 3 kinase (PI3K)-protein kinase B (AKT) and mitogen-activated protein kinase (MAPK) signaling pathways. The molecular docking results showed that the core ingredients of LJZW had good binding ability with the core targets of CD. A series of experiments demonstrated that LJZW could effectively attenuate TNBS-induced colitis symptoms, inhibit the inflammatory response, and protect intestinal barrier function by inhibiting the PI3K-AKT and MAPK signaling pathways, thus preventing and treating CD. ConclusionLJZW has the characteristics of multi-component, multi-target, and multi-pathway treatment, which helps to improve the treatment of CD, protect the intestinal barrier, and exert the effect of anti-inflammatory therapy by inhibiting PI3K-AKT and MAPK signaling pathways.

Lactobacillus from fermented bamboo shoots prevents inflammation in DSS-induced colitis mice via modulating gut microbiome and serum metabolites

Fermented bamboo shoots (FBS) is a region-specific food widely consumed in Southwestern China, with Lactobacillus as the predominant fermenting bacteria. However, the probiotic potential of Lactobacillus derived from FBS reminds largely unexplored, especially for diseases with a low prevalence in areas consuming FBS, namely, inflammatory bowel disease. In this study, Lactiplantibacillus pentosus YQ001 and Lentilactobacillus senioris YQ005 were screening by in vitro probiotic tests to further investigate the probiotic-like bioactivity in dextran sulfate sodium (DSS)-induced ulcerative colitis (UC) mouse. They exhibited more positive probiotic effects than Lactobacillus rhamnosus GG in preventing intestinal inflammatory response. The results revealed that both strains improved the abundance of deficient intestinal microbiota in UC mice, including Muribaculaceae and Akkermansia. In the serum metabolome, they modulated the DSS-disturbed levels of metabolites, with significant increment of cinnamic acid. Meanwhile, they reduced the expression levels of interleukin-1β (IL-1β), interleukin-6 (IL-6) inflammatory factors and increased zonula occludens-1 (ZO-1), Occludin, and cathelicidin-related antimicrobial peptide (CRAMP) in the colon. Consequently, these results demonstrated that Lactobacillus spp. isolates derived from FBS showed promising probiotic activity based on the gut microbiome homeostasis modulation, anti-inflammation and intestinal barrier protection in UC mice.

Gut microbiota contributes to high-altitude hypoxia acclimatization of human populations

BackgroundThe relationship between human gut microbiota and high-altitude hypoxia acclimatization remains highly controversial. This stems primarily from uncertainties regarding both the potential temporal changes in the microbiota under such conditions and the existence of any dominant or core bacteria that may assist in host acclimatization.ResultsTo address these issues, and to control for variables commonly present in previous studies which significantly impact the results obtained, namely genetic background, ethnicity, lifestyle, and diet, we conducted a 108-day longitudinal study on the same cohort comprising 45 healthy Han adults who traveled from lowland Chongqing, 243 masl, to high-altitude plateau Lhasa, Xizang, 3658 masl, and back. Using shotgun metagenomic profiling, we study temporal changes in gut microbiota composition at different timepoints. The results show a significant reduction in the species and functional diversity of the gut microbiota, along with a marked increase in functional redundancy. These changes are primarily driven by the overgrowth of Blautia A, a genus that is also abundant in six independent Han cohorts with long-term duration in lower hypoxia environment in Shigatse, Xizang, at 4700 masl. Further animal experiments indicate that Blautia A-fed mice exhibit enhanced intestinal health and a better acclimatization phenotype to sustained hypoxic stress.ConclusionsOur study underscores the importance of Blautia A species in the gut microbiota’s rapid response to high-altitude hypoxia and its potential role in maintaining intestinal health and aiding host adaptation to extreme environments, likely via anti-inflammation and intestinal barrier protection.

Human β-casein-derived peptide BCCY-1 improved the intestinal barrier integrity by regulating the TLR4/eNOS/3-Nitrotyrosine axis

Necrotizing enterocolitis (NEC) is a lethal gastrointestinal disease affecting premature infants. Although earlier studies have highlighted protective effects of milk-derived peptides against NEC, the role of the human β-casein-derived peptide BCCY-1 in intestinal barrier protection has never been investigated. Here, we showed that BCCY-1 alleviated the phenotype of NEC, reduced intestinal expression of Toll-like receptor 4 (TLR4) and interleukin-6, and improved the intestinal barrier integrity. NEC-associated multi-organ injury and impaired bone marrow hematopoiesis were also attenuated by BCCY-1. Metabolic screening revealed significant changes in intestinal metabolites in the NEC and NEC + BCCY-1 groups. Further analysis disclosed inhibition of 3-Nitrotyrosine formation due to the preservation of endothelial nitric oxide synthase (eNOS) activity, which was associated with the interactions between BCCY-1 and lipopolysaccharides, leading to disruption of TLR4 signaling. Our findings suggested that BCCY-1 improved intestinal barrier integrity through modulating the TLR4/eNOS/3-Nitrotyrosine axis, highlighting its potential role in the maintenance of intestinal health.

Polygonatum cyrtonema saponin supplementation ameliorated DSS-induced intestinal barrier injury via targeting the PI3K/AKT/mTOR-mediated autophagy/microbiota axis

Autophagy is pivotal for the management of intestinal homeostasis, modulation of intestinal immunity response and anti-microbial protection. Previous studies have documented the protective function of Polygonatum cyrtonema Saponin (PCS) against intestinal injury, but whether PCS modulated autophagy and its associated responses remained unknown. A model of dextran sodium sulfate (DSS)- elicited intestinal injury was employed to confirm this hypothesis. The results showed that PCS effectively relieved the typical symptoms of DSS-induced weight reduction, shortened colon length, and augmented disease activity index score, down-regulated organ indices, reduced hepatic oxidative stress, and inhibited excessive inflammatory mediators. Meanwhile, PCS intervention ameliorated the intestinal barrier dysfunction via promoting the differentiation of goblet cells and augmenting the expression of tight junction proteins (TJs). It also suppressed apoptosis in intestinal cells by altering the Bcl-2/Bax ratios and diminishing the expressions of Caspase-9 and Caspase-3. Additionally, PCS remarkably enhanced autophagy by modulating the PI3K/AKT/mTOR signal pathway. More importantly, the classical autophagy inducer rapamycin augmented the beneficial effects of PCS. In contrast, the autophagy inhibitor 3-methyladenine essentially eliminated the above effects, revealing a role for autophagy in the response. Further studies have demonstrated that PCS intervention improved the diversities of the intestinal flora, increased occupancy of beneficial bacteria in Lachnospiraceaeae and Akkermansia, which was closely associated with autophagy. Taken together, these findings demonstrated that PCS is a potential supplier of prebiotics by modulating immunity, repairing intestinal mucosal injury, regulating autophagy and intestinal flora, and autophagy is a key target for PCS-mediated intestinal barrier protection.

Heat acclimation with probiotics-based ORS supplementation alleviates heat stroke-induced multiple organ dysfunction via improving intestinal thermotolerance and modulating gut microbiota in rats.

Heat stroke (HS) is a critical condition with extremely high mortality. Heat acclimation (HA) is widely recognized as the best measure to prevent and protect against HS. Preventive administration of oral rehydration salts III (ORSIII) and probiotics have been reported to sustain intestinal function in cases of HS. This study established a rat model of HA that was treated with probiotics-based ORS (ORSP) during consecutive 21-day HA training. The results showed that HA with ORSP could attenuate HS-induced hyperthermia by regulating thermoregulatory response. We also found that HA with ORSP could significantly alleviate HS-induced multiple organ injuries. The expression levels of a series of heat-shock proteins (HSPs), including HSP90, HSP70, HSP60, and HSP40, were significantly up-regulated from the HA training. The increases in intestinal fatty acid binding protein (I-FABP) and D-Lactate typically seen during HS were decreased through HA. The representative TJ proteins including ZO-1, E-cadherin, and JAM-1 were found to be significantly down-regulated by HS, but sustained following HA. The ultrastructure of TJ was examined by TEM, which confirmed its protective effect on the intestinal barrier protection following HA. We also demonstrated that HA raised the intestinal levels of beneficial bacteria Lactobacillus and lowered those of the harmful bacteria Streptococcus through 16S rRNA gene sequencing. These findings suggest that HA with ORSP was proven to improve intestinal thermotolerance and the levels of protective gut microbiota against HS.

Epigallocatechin-3-gallate mitigates cadmium-induced intestinal damage through modulation of the microbiota-tryptophan-aryl hydrocarbon receptor pathway

Early studies have shown that the gut microbiota is a critical target during cadmium exposure. The prebiotic activity of epigallocatechin-3-gallate (EGCG) plays an essential role in treating intestinal inflammation and damage. However, the exact intestinal barrier protection mechanism of EGCG against cadmium exposure remains unclear. In this experiment, four-week-old mice were exposed to cadmium (5 mg kg−1) for four weeks. Through 16 S rDNA analysis, we found that cadmium disrupted the gut microbiota and inhibited the indole metabolism pathway of tryptophan (TRP), which serves as the principal microbial production route for endogenous ligands to activate the aryl hydrocarbon receptor (AhR). Additionally, cadmium downregulated the intestinal AhR signaling pathway and harmed the intestinal barrier function. Treatment with EGCG (20 mg kg−1) and the AhR agonist 6-Formylindolo[3,2-b] carbazole (FICZ) (1 μg/d) significantly activated the AhR pathway and alleviated intestinal barrier injury. Notably, EGCG partially restored the gut microbiota and upregulated the TRP-indole metabolism pathway to increase the level of indole-related AhR agonists. Our findings demonstrate that cadmium dysregulates common gut microbiota to disrupt TRP metabolism, impairing the AhR signaling pathway and intestinal barrier. EGCG reduces cadmium-induced intestinal functional impairment by intervening in the intestinal microbiota to metabolize AhR agonists. This study offers insights into the toxic mechanisms of environmental cadmium and a potential mechanism to protect the intestinal barrier with EGCG.

Intestinal Barrier Protection by Probiotic Lactobacillus-Associated Indoles in Caco-2 and Enteroids

Gut bacteria generate from dietary tryptophan (trp) indole compounds, which act as potent signaling molecules intricately involved in the regulation of intestinal homeostasis and barrier integrity. Lactobacillus rhamnosus GG (LGG), a widely used probiotic, has demonstrated ability to restore the gut barrier in animal models of colitis and sepsis, as well as in children with irritable bowel syndrome. To investigate the hypothesis that LGG-derived indoles are responsible for its gut barrier-enhancing properties, we fed gnotobiotic mice trp-suffcient and trp-deficient diets. We then monocolonized them with LGG, using PBS gavaged mice as a control, and analyzed the ileal transcriptome by bulk RNA sequencing and both fecal and serum metabolomes by LC-MS. Using our novel bioinformatic tool METRCA, which correlates metabolites and gene networks, we uncovered an unexpected and substantial influence of indole spatial distribution on genes associated with gut integrity: some were significantly positively linked to tight junction (TJ) genes exclusively from the luminal side, some exclusively from the serum, and others from both. Specifically, we identified nine indoles—indole-acetamide (IAM), indole-carboxaldehyde (IAL), indole-3-lactic acid (ILA), indole-3-propionic acid (IPA), indole-3-acrylic acid (IAR), indole-3-carbinol (ICB), indole-acetic acid (IAA), indole-3-acetonitrile (IAN), and indole-3-carboxylic acid (ICA)—that demonstrated the potential to maintain gut barrier function. To assess their impact, we used a high-throughput system that measured permeability through transepithelial electrical resistance (TEER) and FITC-dextran (4 kDa) in polarized Caco-2 cells. By luminally challenging cells with Clostridium diffcile toxins (TOX), we induced barrier disruption to model leaky gut. Intriguingly, when applied luminally, IAA, IAN, ICA, and ILA rescued the TEER of Caco-2 cells exposed to TOX, while IAM, IAL, and ILA were effective when applied basolaterally, suggesting a strong polar component to their barrier repair capacity. FITC transport revealed a significant basolateral rescue effect of IAM and luminal rescue effect of IAA and ICA, indicating that different sets of indoles are required to repair the pore and leak pathways. Furthermore, we confirmed that basolateral IAM rescued FITC permeability and induced increased expression of TJ genes Tjp1 and Ocln in enteroids challenged with lipopolysaccharides. In summary, our research highlights the potential beneficial therapeutic application of certain indoles in repairing disrupted gut barriers. NIHR01-AT010243 (NG, RF), R01DK119198 (NG), NSF 1754783 (RF). This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

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

Background and aimsIncreased 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. MethodsMice 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. ResultsTreatment 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. ConclusionsSOP 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.

Mechanism of Fushen Granules treat peritoneal dialysis-related peritonitis by regulating TLR4/NF-κB pathway:based on network pharmacology and animal experiments

Network pharmacology was employed to probe into the mechanism of Fushen Granules in treating peritoneal dialysis-rela-ted peritonitis(PDRP) in rats. The main active components of Fushen Granules were searched against the Traditional Chinese Medicine Systems Pharmacology Database and Analysis Platform, and their targets were predicted. PDRP-related targets were retrieved from DisGeNET and other databases. The common targets shared by the drug and the disease were identified by the online tool, and protein-protein interaction(PPI) network of the common targets. The obtained 276 common targets were imported into DAVID for GO function enrichment and KEGG pathway enrichment. The main signaling pathway of Fushen Granules in the treatment of PDRP was predicted as Toll-like receptor 4(TLR4)/nuclear factor(NF)-κB. The rat model of uremia was induced by 5/6 nephrectomy. From two weeks after operation, the rat model of peritoneal dialysis(PD) was established by intraperitoneal injection of 20 mL dialysate with 1.25% glucose every day. The sham operation group and model group received 2 mL normal saline by gavage every day. The rats in Fushen Gra-nules groups were administrated with 2 mL solutions of low-(0.54 g·kg~(-1)), medium-(1.08 g·kg~(-1)) and high-dose(2.16 g·kg~(-1)) Fushen Granules every day. The bifico group received 2 mL(113.4 mg·kg~(-1)) of bifico solution every day. At the end of the 8th week, the levels of serum creatinine(Scr) and blood urea nitrogen(BUN) in each group were measured. The serum levels of hypersensitive C reactive protein(hs-CRP), tumor necrosis factor(TNF)-α, and interleukin(IL)-6 were measured, and the pathological changes in the colon tissue were observed by hematoxylin-eosin(HE) staining. The serum levels of lipopolysaccharide(LPS) and lipopolysaccharide-binding protein(LBP) of rats were measured, and the expression levels of LBP, TLR4, NF-κB p65, inhibitor of κB kinase α(IκBα), TNF-α, and IL-1β in the colon tissue were determined. Compared with sham operation group, the model group had abnormal structure of all layers of colon tissue, sparse and shorter intestinal villi, visible edema in mucosal layer, wider gap, obvious local inflammatory cell infiltration, significantly decreased body weight(P&lt;0.01), and significantly increased kidney function index(Scr, BUN) content(P&lt;0.01). Serum levels of inflammatory cytokines(hs-CRP, TNF-α, IL-6), LPS and LBP were significantly increased(P&lt;0.01), protein expressions of LBP, TLR4, NF-κB p65, TNF-α and IL-1β were significantly increased(P&lt;0.01), and protein expressions of IκBα were significantly decreased(P&lt;0.01). Compared with model group, intestinal villi damage in colonic tissue of rats in low-, medium-and high-dose Fushen Granules groups and bifico group were alleviated to different degrees, edema in submucosa was alleviated, space was narrowed, and inflammatory cell infiltration in lamina propria was reduced. The contents of renal function index(Scr, BUN) and serum inflammatory factors(hs-CRP, TNF-α, IL-6) were significantly decreased(P&lt;0.05 or P&lt;0.01) in medium-and high-dose Fushen Granules groups and bifico group(P&lt;0.05 or P&lt;0.01). Serum LPS and LBP contents in Fushen Granules group and bifico group were significantly decreased(P&lt;0.01), protein expressions of LBP, TLR4, NF-κB p65, TNF-α and IL-1β in Fushen Granules group were significantly decreased(P&lt;0.05 or P&lt;0.01), and protein expressions of IκBα were significantly increased(P&lt;0.01). The expression of LBP protein in bifico group was significantly decreased(P&lt;0.01). The results suggest that Fushen Granules can protect the residual renal function of PD rats, reduce the inflammatory response, and protect the colon tissue. Based on network pharmacology, TLR4/NF-κB pathway may be the main signaling pathway of Fushen granule in the treatment of PDRP. The results showed that Fushen Granules could improve intestinal inflammation and protect intestinal barrier to prevent PDRP by regulating the expression of key factors in TLR4/NF-κB pathway in colon of PD rats.

Sialyllactose Enhances the Short-Chain Fatty Acid Production and Barrier Function of Gut Epithelial Cells via Nonbifidogenic Modification of the Fecal Microbiome in Human Adults.

Although various benefits of human milk oligosaccharides (HMOs) have been reported, such as promoting Bifidobacterium growth in the infant gut, their effects on adults have not been fully studied. This study investigated the effects of two types of sialyllactose, 3'-sialyllactose (3'-SL) and 6'-sialyllactose (6'-SL), on the adult intestinal microbiome using the simulator of human intestinal microbial ecosystem (SHIME®), which can simulate human gastrointestinal conditions. HPLC metabolite analysis showed that sialyllactose (SL) supplementation increased the short-chain fatty acid content of SHIME culture broth. Moreover, 16S rRNA gene sequencing analysis revealed that SL promoted the growth of Phascolarctobacterium and Lachnospiraceae, short-chain fatty acid-producing bacteria, but not the growth of Bifidobacterium. Altogether, both types of SL stimulated an increase in short-chain fatty acids, including propionate and butyrate. Additionally, SHIME culture supernatant supplemented with SL improved the intestinal barrier function in Caco-2 cell monolayers. These results suggest that SL could act as a unique prebiotic among other HMOs with a nonbifidogenic effect, resulting in intestinal barrier protection.

Vitamin D/vitamin D receptor protects intestinal barrier against colitis by positively regulating Notch pathway.

Vitamin D/Vitamin D receptor (VD/VDR) signaling and the Notch pathway are involved in intestinal barrier restoration in colitis; however, their relationship and underlying mechanism are largely unknown. Therefore, this study aimed to investigate the role and mechanism of VD/VDR and the Notch pathways in intestinal barrier protection. Genetic Vdr knockout (VDR KO) and VD deficient (VDd) mice were established, and colitis was induced by feeding 2.5% dextran sodium sulfate (DSS) water. Mechanistic studies, including real-time PCR, immunofluorescence, Western blotting and dual-luciferase reporter assays, were performed on cultured Caco-2 cells and intestinal organoids. VD deficiency and VDR genetical KO increased the severity of DSS-induced colitis in mice, which presented a higher disease activity index score, increased intestinal permeability, and more severe intestinal histological damage than controls, accompanied by decreased and disrupted claudin-1 and claudin-3. Moreover, inhibition of Notch pathway by LY411,575 aggravated the severity of DSS-induced colitis and intestinal injury. In Caco-2 cells and intestinal organoids, the expression of Notch-1, N1ICD and Hes1 decreased upon downregulation or KO of VDR but increased upon paricalcitol (PAR, a VDR agonist) treatment. Meanwhile, PAR rescued claudin-1 and claudin-3 impairments that resulted from TNF-α exposure but failed to restore claudin-3 upon Notch inhibition. The dual-luciferase reporter assay further suggested that VD/VDR positively regulated the Notch signaling pathway by modulating Notch-1 transcription. VD/VDR positively modulates Notch activation by promoting Notch-1 transcription to maintain intestinal tight junction integrity and barrier function. This highlights the VD/VDR-Notch pathway as a potential new therapeutic target for protecting the intestinal barrier against ulcerative colitis.

Research progress in the treatment of inflammatory bowel disease with natural polysaccharides and related structure-activity relationships.

Inflammatory bowel disease (IBD) comprises a group of highly prevalent and chronic inflammatory intestinal tract diseases caused by multiple factors. Despite extensive research into the causes of the disease, IBD's pathogenic mechanisms remain unclear. Moreover, side effects of current IBD therapies restrict their long-term clinical use. In contrast, natural polysaccharides exert beneficial anti-IBD effects and offer advantages over current anti-IBD drugs, including enhanced safety and straightforward isolation from abundant and reliable sources, and thus may serve as components of functional foods and health products for use in IBD prevention and treatment. However, few reviews have explored natural polysaccharides with anti-IBD activities or the relationship between polysaccharide conformation and anti-IBD biological activity. Therefore, this review aims to summarize anti-IBD activities and potential clinical applications of polysaccharides isolated from plant, animal, microorganismal, and algal sources, while also exploring the relationship between polysaccharide conformation and anti-IBD bioactivity for the first time. Furthermore, potential mechanisms underlying polysaccharide anti-IBD effects are summarized, including intestinal microbiota modulation, intestinal inflammation alleviation, and intestinal barrier protection from IBD-induced damage. Ultimately, this review provides a theoretical foundation and valuable insights to guide the development of natural polysaccharide-containing functional foods and nutraceuticals for use as dietary IBD therapies.

Immunoregulation of bovine lactoferrin together with osteopontin promotes immune system development and maturation.

The immune system of infants is partly weak and immature, and supplementation of infant formula can be of vital importance to boost the development of the immune system. Lactoferrin (LF) and osteopontin (OPN) are essential proteins in human milk with immunoregulation function. An increasing number of studies indicate that proteins have interactions with each other in milk, and our previous study found that a ratio of LF : OPN at 1 : 5 (w/w, denoted as LOP) had a synergistic effect on intestinal barrier protection. It remains unknown whether LOP can also exert a stronger effect on immunoregulation. Hence, we used an in vitro model of LPS-induced macrophage inflammation and in vivo models of LPS-induced intestinal inflammation and early life development. We showed that LOP increased the secretion of the granulocyte-macrophage colony-stimulating factor (132%), stem cell factor (167%) and interleukin-3 (176%) in bone marrow cells, as well as thymosin (155%) and interleukin-10 (161%) in the thymus, more than LF or OPN alone during development, and inhibited changes in immune cells and cytokines during the LPS challenge. In addition, analysis of the components of digested proteins in vitro revealed that differentially expressed peptides may provide immunoregulation. Lastly, LOP increased the abundance of Rikenellaceae, Muribaculum, Faecalibaculum, and Elisenbergiella in the cecum content. These results imply that LOP is a potential immunomodifier for infants and offers a new theoretical basis for infant formula innovation.

Bound polyphenols in insoluble dietary fiber of navel orange peel modulate LPS-induced intestinal-like co-culture inflammation through CSF2-mediated NF-κB/JAK-STAT pathway.

Our laboratory previously extracted bound polyphenols (BPP) in insoluble dietary fiber from navel orange peel (NOP-IDF), and the aim of this study was to investigate the anti-inflammatory activity and potential molecular mechanisms of BPP by establishing an LPS-induced intestinal-like Caco-2/RAW264.7 co-culture inflammation model. The results demonstrated that BPP reduced the expression of cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS), as well as the production of pro-inflammatory cytokines, nitric oxide (NO), and reactive oxidative species (ROS) during the inflammatory damage process. Furthermore, BPP alleviated the lipopolysaccharides (LPS)-induced intestinal barrier damage by attenuating the decrease in trans-epithelial electrical resistance (TEER), diamine oxidase (DAO) activity, and intestinal alkaline phosphatase (IAP) activity, as well as the downregulation of ZO-1, Occludin, and Claudin-1 protein expression levels. RNA-seq results on RAW264.7 cells in the co-culture model showed that the NF-κB and JAK-STAT pathways belonged to the most significantly affected signaling pathways in the KEGG analysis, and western blot confirmed that they are essential for the role of BPP in intestinal inflammation. Additionally, overexpression of the granulocyte-macrophage colony-stimulating factor (CSF2) gene triggered abnormal activation of the NF-κB and JAK-STAT pathways and high-level expression of inflammatory factors, while BPP effectively improved this phenomenon. The above results suggested that BPP could inhibit intestinal inflammatory injury and protect intestinal barrier integrity through CSF2-mediated NF-κB and JAK-STAT pathways.

P-hydroxy benzaldehyde attenuates intestinal epithelial barrier dysfunction caused by colitis via activating the HNF-1β/SLC26A3 pathway.

Intestinal epithelial barrier dysfunction is intricately linked to the pathogenesis of ulcerative colitis (UC). Dietary interventions that bolster intestinal epithelial barrier function can effectively thwart UC onset. Our prior research revealed that p-Hydroxy benzaldehyde (HD), a phenolic compound from Nostoc commune (an edible cyanobacterium), markedly upregulated the expression of E-cadherin, a pivotal protein in intestinal mucosa, thereby mitigating mucosal damage in mice afflicted with dextran sulfate sodium (DSS)-induced colitis. Nevertheless, the precise molecular mechanisms underpinning HD's ameliorative effects on intestinal epithelial barrier dysfunction remain elusive. Dextran sodium sulfate (DSS)-induced colitis mouse model was established, and the successful establishment of the model was determined by evaluating the changes in body weight, disease activity index (DAI), colonic histopathology, and white blood cell count. Transmission electron microscopy (TEM) observed the ultrastructural changes of intestinal villi. The levels of inflammatory factors ( IFN-γ IL-13 ) and intestinal permeability indicators (FITC-Dextran, DAO, ET, and D-LA ) were detected by Enzyme-linked immunosorbent assay (ELISA). Western blotting (WB) and immunohistochemistry (IHC) were used to detect the expression of intestinal barrier integrity-related factors such as tight junction protein TJs (ZO-1, occludin) and adhesion junction protein AJs (E-cadherin). Furthermore, WB, Pull-down assay, drug affinity reaction target stability (DARTS) assay, molecular docking and molecular dynamics (MD) simulation were used to determine the potential target and molecular mechanism of HD. HD intervention significantly alleviated the symptoms of colitis mice, inhibited the weight loss and colon shortening, reduced DAI score and colon pathological score, maintained the ultrastructure of intestinal villi in colon tissue, and significantly reduced the inflammatory factors IFN-γ, IL-13 and the number of white blood cells in colon tissue of colitis mice. HD could also reduce the levels of FITC-Dextran, DAO, ET, and D-LA and increase the expression of ZO-1, occludin, and E-cadherin in the colonic tissues of colitis mice, thereby maintaining the impaired intestinal barrier function caused by colitis. Mechanically, HD augmented the expression of hepatocyte nuclear factor 1β (HNF-1β) and DRA. Adeno-associated virus (AAV)-HNF-1β shRNA or Lentivirus-mediated HNF-1β knockdown effectively abolished HD-induced intestinal barrier protection, as well as the promotion of solute carrier family 26 member 3 (SLC26A3) expression levels. SLC26A3 siRNA effectively reversed the inhibition of intestinal permeability by HD. Pull-down assay, DARTS analysis, molecular docking, and MD results showed high binding strength, interaction efficiency and remarkable stability between HNF-1β and HD. This study elucidates HD's role in forestalling intestinal epithelial barrier disruption under colitis conditions. Mechanistic investigations revealed that HD fortifies TJs and AJs expression via the HNF-1β/SLC26A3 pathway, thus preserving the lower intestinal epithelial barrier's integrity in UC.

Effect of ultrasound-guided lumbar square muscle block on stress response in patients undergoing radical gastric cancer surgery.

Radical surgery is a common treatment for patients with gastric cancer; however, it can lead to postoperative complications and intestinal barrier dysfunction. Ultrasound-guided quadratus lumborum block is often used for postoperative analgesia, but its effects on stress response and intestinal barrier function are not well understood. To investigate the effects of an ultrasound-guided quadratus lumborum block on stress response and intestinal barrier function in patients undergoing radical surgery for gastric cancer. A total of 100 patients undergoing radical surgery for gastric cancer were randomly categorized into observation and control groups. Plasma adrenaline and cortisol levels, intestinal mucosal barrier indexes, and complication rates were compared between the two groups before, during, and 1 day after surgery. The observation group had significantly lower plasma adrenaline and cortisol levels during surgery and at 1 day postoperatively than that of the control group (P < 0.05). Additionally, intestinal barrier indexes (endotoxin and D-dimer) at 1 day postoperatively were significantly lower in the observation group than in the control group (P < 0.05). Ultrasound-guided quadratus lumborum block could reduce stress response, protect intestinal barrier function, and decrease the incidence of complications in patients undergoing radical surgery for gastric cancer. This technique has the potential for clinical applications.

Intestinal epithelial barrier protective effect of nut oils (walnut, almond, pistachio, and pine nut) on TNF-α/IFN-γ induced damage in Caco-2 cell monolayers

Damage to the intestinal barrier causes intestinal inflammation, which could lead to the development of gastrointestinal diseases. Nut oils contain an abundance of unsaturated fatty acids, which are responsible for most of the bioactivities of nut oils. Here, the protective effect of four nut oils on the intestinal epithelial barrier was confirmed using Caco-2 cells damaged by tumor necrosis factor-α/interferon-γ treatment. Nut oils effectively increased transepithelial electronic resistance and lowered paracellular fluorescein isothiocyanate-dextran permeability in damaged Caco-2 cells. Furthermore, the nut oils inhibited the pro-inflammatory cytokine production of interleukin-6, which was induced by the inflammatory response. In particular, walnut oil effectively improved tight junction protein (occludin and zonula occludens-1) expression and distribution in damaged Caco-2 cells. In conclusion, our findings suggest that nut oils are promising candidates for impaired intestinal barrier protection.