Protected Caco-2 Cells Research Articles

Antioxidant properties of phenolic extracts of murtilla pomace: First report on the importance of soluble and insoluble-bound compounds

Some native Chilean berries, including murtilla, have gained attention for their high phenolic content which renders them attractive for the beverage industry. However, phenolic-rich by-products are generated during the production of murtilla juice (murtilla pomace), and there has been no scientific consideration of this by-product as a source of different forms of phenolic compounds. The aim of this study was thus to obtain phenolic extracts from the soluble fraction (free, esterified, and etherified) of murtilla pomace as well from the counterpart that contains insoluble-bound compounds, and evaluate their antioxidant properties. The fraction obtained from the insoluble-bound form (insoluble-bound phenolic hydrolysates) showed the highest total phenolic content, reducing power and antioxidant capacity, as evaluated by the FRAP and ORAC assay, respectively. The results revealed the presence of different compounds in each fraction, highlighting important levels of phenolic acids (e.g., gallic acid) and flavonoids (e.g., quercetin and its derivatives) as evaluated by UPLC-ESI-MS/MS. The most prominent fraction (released from the insoluble-bound form) exhibited antioxidant activity (in concentrations as low as 0.0025 μM of total phenolic acids and 0.0002 μM of total flavonoids) in Caco-2 cells. The necessary concentration of quercetin to protect Caco-2 cells against the hydrogen peroxide-induced oxidative stress was twenty times lower than the concentration needed for gallic acid to exert the same level of antioxidant protection. We can therefore suggest that the quercetin concentration would be a better-quality control indicator for functional ingredients, food supplements, and/or nutraceutical products generated from the insoluble-bound phenolic fraction of murtilla pomace.

Sea Cucumber Viscera Processed by Protease Hydrolysis Combined with Cordyceps militaris Fermentation Protect Caco-2 Cells against Oxidative Damage via Enhancing Antioxidant Capacity, Activating Nrf2/HO-1 Pathway and Improving Cell Metabolism.

Excessive reactive oxygen species (ROS) may lead to oxidative damage and metabolic disorder. The pathogenesis of human bowel inflammation is closely related to oxidative damage of intestinal epithelial cells caused by ROS. This study aimed to explore the high-value utilization of the byproducts of sea cucumber in antioxidant food for colitis prevention. The technology of protease hydrolysis combined with Cordyceps militaris fermentation was used to obtain fermented sea cucumber viscera protease hydrolysates (FSVHs). The results revealed that FSVH could enhance antioxidant capacity and alleviate oxidative damage and apoptosis by activating the Nrf2/HO-1 pathway and triggering the self-protection immune mechanisms. Moreover, the FSVH supplementation could upregulate antioxidant-related metabolic pathways of Caco-2 cells such as glutathione metabolism, confirming the enhanced antioxidant capacity of damaged cells. In summary, FSVH could exert protective effects on Caco-2 cells in response to oxidative damage, providing a promising prospect for sea cucumber resource utilization and colitis prevention.

Whey Protein Sodium-Caseinate as a Deliverable Vector for EGCG: In Vitro Optimization of Its Bioaccessibility, Bioavailability, and Bioactivity Mode of Actions.

Epigallocatechin gallate (EGCG), the principal catechin in green tea, exhibits diverse therapeutic properties. However, its clinical efficacy is hindered by poor stability and low bioavailability. This study investigated solid particle-in-oil-in-water (S/O/W) emulsions stabilized by whey protein isolate (WPI) and sodium caseinate (NaCas) as carriers to enhance the bioavailability and intestinal absorption of EGCG. Molecular docking revealed binding interactions between EGCG and these macromolecules. The WPI- and NaCas-stabilized emulsions exhibited high encapsulation efficiencies (>80%) and significantly enhanced the bioaccessibility of EGCG by 64% compared to free EGCG after simulated gastrointestinal digestion. Notably, the NaCas emulsion facilitated higher intestinal permeability of EGCG across Caco-2 monolayers, attributed to the strong intermolecular interactions between caseins and EGCG. Furthermore, the emulsions protected Caco-2 cells against oxidative stress by suppressing intracellular reactive oxygen species generation. These findings demonstrate the potential of WPI- and NaCas-stabilized emulsions as effective delivery systems to improve the bioavailability, stability, and bioactivity of polyphenols like EGCG, enabling their applications in functional foods and nutraceuticals.

From Grape By-Products to Enriched Yogurt Containing Pomace Extract Loaded in Nanotechnological Nutriosomes Tailored for Promoting Gastro-Intestinal Wellness.

Grape pomace is the main by-product generated during the winemaking process; since it is still rich in bioactive molecules, especially phenolic compounds with high antioxidant power, its transformation in beneficial and health-promoting foods is an innovative challenge to extend the grape life cycle. Hence, in this work, the phytochemicals still contained in the grape pomace were recovered by an enhanced ultrasound assisted extraction. The extract was incorporated in liposomes prepared with soy lecithin and in nutriosomes obtained combining soy lecithin and Nutriose FM06®, which were further enriched with gelatin (gelatin-liposomes and gelatin-nutriosomes) to increase the samples' stability in modulated pH values, as they were designed for yogurt fortification. The vesicles were sized ~100 nm, homogeneously dispersed (polydispersity index < 0.2) and maintained their characteristics when dispersed in fluids at different pH values (6.75, 1.20 and 7.00), simulating salivary, gastric and intestinal environments. The extract loaded vesicles were biocompatible and effectively protected Caco-2 cells against oxidative stress caused by hydrogen peroxide, to a better extent than the free extract in dispersion. The structural integrity of gelatin-nutriosomes, after dilution with milk whey was confirmed, and the addition of vesicles to the yogurt did not modify its appearance. The results pointed out the promising suitability of vesicles loading the phytocomplex obtained from the grape by-product to enrich the yogurt, offering a new and easy strategy for healthy and nutritional food development.

Daphnetin attenuates intestinal inflammation, oxidative stress, and apoptosis in ulcerative colitis via inhibiting REG3A-dependent JAK2/STAT3 signaling pathway.

Daphnetin is a natural coumarin compound with anti-inflammatory, anti-oxidant, and anti-apoptotic effects, which has been previously demonstrated to ameliorate DSS-induced ulcerative colitis (UC). However, the molecular mechanism involved in the daphnetin-mediated pathological process of UC remains unclarified. The current study used DSS-induced mice and LPS-challenged Caco-2 cells as UC models. Bodyweight, disease activity index (DAI) score, and colon length were used to evaluate the severity of colitis. The histological changes in colon tissues were observed using H&E and PAS staining. Protein levels were detected by western blot. The malondialdehyde (MDA) and superoxide dismutase (SOD) activities were used to assess oxidative stress. Inflammatory responses were evaluated by detecting the levels of inflammatory cytokines (IFN-r, IL-1β, IL-6, and TNF-α) using flow cytometry. CCK-8 and TUNEL assay were employed to determine cell growth and cell death, respectively. The results showed that daphnetin could ameliorate the severity of colitis and attenuate the damage to intestinal structure in DSS-induced mice. Compared with the DSS group, the expression of ZO-1, occludin, and anti-apoptotic protein (BCL-2) was increased while the level of pro-apoptotic proteins (Bax and cleaved caspase 3) was decreased in DSS + daphnetin group. The activity of MDA and SOD, as well as the levels of inflammatory cytokines were substantially suppressed by daphnetin. In consistency, in vitro assays indicated that daphnetin protected Caco-2 cells from LPS-stimulated viability impairment, apoptosis, oxidative stress, and inflammation. Furthermore, daphnetin suppressed the activity of JAK2/STAT signaling in LPS-induced Caco-2 cells in a REG3A-dependent manner. REG3A overexpression abated the ameliorative effects of daphnetin while JAK2/STAT signaling inhibition functioned synergically with daphnetin in LPS-stimulated Caco-2 cells. Collectively, this study deepened the understanding of the therapeutic effects of daphnetin on UC and uncovered for the first time that daphnetin functioned through REG3A-activated JAK2/STAT3 signaling in UC, which may provide novel insights for the treatment of UC.

In vitro antibacterial activity of Bacillus coagulans T242 on Caco-2 cells infected with Salmonella Typhimurium

This study aimed to investigate the antibacterial activity of Bacillus coagulans (B. coagulans) T242 and its ability to alleviate the infection of Caco-2 cells with Salmonella Typhimurium (S. Typhimurium) SL1344. B. coagulans T242 has a broad spectrum of the antibacterial activity. The cell-free supernatants of B. coagulans T242 inhibited the growth of S. Typhimurium SL1344 and changed its cell morphology. B. coagulans T242 inhibited the adhesion and invasion of S. Typhimurium SL1344 to Caco-2 cells by adhering to Caco-2 cells, significantly reduced the production of interleukin-6 (IL-6), Interleukin-8 (IL-8) and tumor necrosis factor-α (TNF-α) which induced by S. Typhimurium SL1344, also increased interleukin-10 (IL-10) production, thereby alleviating the inflammatory response of Caco-2 cells. B. coagulans T242 vegetative cells and spores could alleviate the decreased expression of tight junction proteins (Claudin-1, Occludin and ZO-1) caused by S. Typhimurium SL1344 infection in Caco-2 cells by increasing the expression of Claudin-1, Occludin and ZO-1. This study demonstrated that B. coagulans T242 could protect Caco-2 cells by adhesion, reducing inflammatory response and enhancing intestinal barrier function. Therefore, B. coagulans T242 will hopefully be an effective alternative to antibiotics, and this study has important implications for food safety issues.

Daidzein Protects Caco-2 Cells against Lipopolysaccharide-Induced Intestinal Epithelial Barrier Injury by Suppressing PI3K/AKT and P38 Pathways.

The intestinal epithelium provides an important barrier against bacterial endotoxin translocation, which can regulate the absorption of water and ions. The disruption of epithelial barrier function can result in water transport and tight junction damage, or further cause diarrhea. Therefore, reducing intestinal epithelial barrier injury plays an important role in diarrhea. Inflammatory response is an important cause of intestinal barrier defects. Daidzein improving the barrier integrity has been reported, but the effect on tight junction proteins and aquaporins is not well-described yet, and the underlying mechanism remains indistinct in the human intestinal epithelium. This study aimed to investigate the effects and mechanisms of daidzein on intestinal epithelial barrier injury induced by LPS, and a barrier injury model induced by LPS was established with human colorectal epithelial adenocarcinoma cell line Caco-2 cells. We found that daidzein protected the integrity of Caco-2 cell monolayers, reversed LPS-induced downregulation of ZO-1, occludin, claudin-1, and AQP3 expression, maintained intercellular junction of ZO-1, and suppressed NF-κB and the expression of inflammatory factors (TNF-α, IL-6). Furthermore, we found that daidzein suppressed the phosphorylation of the PI3K/AKT and P38 pathway-related proteins and the level of the related genes, and the PI3K/AKT and P38 pathway inhibitors increased ZO-1, occludin, claudin-1, and AQP3 expression. The study showed that daidzein could resist LPS-induced intestinal epithelial barrier injury, and the mechanism is related to suppressing the PI3K/AKT and P38 pathways. Therefore, daidzein could be a candidate as a dietary supplementation or drug to prevent or cure diarrhea.

Isolation and characterization of antioxidant peptides from oyster (Crassostrea rivularis) protein enzymatic hydrolysates.

Peptides from oysters have several bioactive functions. In this study, we identified antioxidant peptides from oysters (Crassostrea rivularis) and investigated their structure-function relationship. We used an 8kDa molecular-weight (MW) cut-off membrane and semiprep reversed-phase liquid chromatography to collect five peptides (F1-F5) and identified the highest-abundance ion-peak sequences AWVDY (F1), MSFRFY(F2), EPLRY(F3), RKPPWPP(F4), and YAKRCFR(F5) having MWs of 652, 850, 676, 877, and 943 Da, respectively, using ultra-performance liquid chromatography-quadrupole/time-of-flight tandem mass spectrometry. These peptides exhibited high antioxidant activities, similar to butylated hydroxytoluene, reduced glutathione, and ascorbic acid. F5 demonstrated the highest scavenging activity for DPPH radicals (IC50=21.75 μg/ml), hydroxyl radicals (IC50=18.75 μg/ml), and superoxide radicals (IC50=11.00 μg/ml), while F3 demonstrated the highest reducing power. Furthermore, F5 significantly protected Caco-2 cells from H2O2-induced oxidative damage. These results suggest that the antioxidant peptide F5 is a promising food additive that protects against oxidative damage.

Preparation, characteristic and anti-inflammatory effect of selenium nanoparticle-enriched probiotic strain Enterococcus durans A8-1

BackgroundElemental selenium, a new type of selenium supplement, can be biosynthesized via microorganisms. This study is to characterize a patent probiotic bacteria Enterococcus durans A8–1, capable of reducing selenite (Se6+ or Se4+) to elemental selenium (Se0) with the formation of Se nanoparticles (SeNPs). MethodsThe selenium nanoparticles synthesized from A8–1 were characterized using scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive spectroscopy (EDS), and X-ray photoelectron energy (XPS). The Caco2 cells were used to investigate the effects of Se-enriched A8–1 on the viability, membrane integrity, and the regulation of cellular inflammation through MTT and ELISA assays. The selenium-enriched metabolic function of A8–1 was analyzed by transcriptome sequencing. ResultsE. durans A8–1 has the ability to synthesize intracellular SeNPs that are incubated with 60 mg/L sodium selenite for 18 h at 37 °C with 7 % inoculum under aerobic conditions. The selenium-enriched transformation rate increased to 43.46 %. After selenium enrichment, there were no significant morphological changes in E. durans A8–1 cells. The cells also exhibited no cytotoxicity when incubated with Caco-2 cells, and increased cellular proliferation. Furthermore, Se-enriched A8–1 cells antagonize the adhesion of S. typhimurium ATCC14028 onto the surface of Caco-2 cells protecting cell membrane integrity and was assessed by measuring LDH and AKP activities (P <0.001, P <0.001). Moreover, Se-enriched A8–1 could protect Caco-2 cells from inflammation induced by lipopolysaccharide and help the cells alleviate the inflammation through the reduced expression of cytokine IL-8 (P = 0.0012, P <0.001) and TNF-α (P <0.001, P <0.001). Based on transcriptome sequencing in Se-enriched E. durans A8–1 cells, there were 485 up-regulated genes and 322 down-regulated genes (Padj < 0.05). There were 19 predicted up-regulated genes that are highly related to the potential selenium metabolism pathway, which focuses on the transportation of Na2SeO3 by membrane proteins, and gradually reduces Na2SeO3 to elemental selenium aggregates that are deposited onto the membrane surface via the intracellular redox response. ConclusionE. durans A8–1 could convert extracellular selenite into intracellular biological SeNPs via redox pathway with strong selenium-rich metabolism, and its biological SeNPs have anti-inflammatory properties, which have the potential for the development of composite selenium nanomaterials and can be further studied for the function of SeNPs with potential applications.

Cystic fibrosis transmembrane conductance regulator prevents ischemia/reperfusion induced intestinal apoptosis via inhibiting PI3K/AKT/NF-κB pathway.

BACKGROUNDIntestinal ischemia/reperfusion (I/R) injury is a fatal syndrome that occurs under many clinical scenarios. The apoptosis of intestinal cells caused by ischemia can cause cell damage and provoke systemic dysfunction during reperfusion. However, the mechanism of I/R-induced apoptosis remains unclear. Cystic fibrosis transmembrane conductance regulator (CFTR) is a cAMP-activated chloride channel. Few researchers have paid attention to its role in intestinal I/R injury, or the relationship between CFTR and intestinal apoptosis induced by hypoxia/reoxygenation (H/R).AIMTo investigate the effects of CFTR on I/R-induced intestinal apoptosis and its underlying molecular mechanisms.METHODSAn intestinal I/R injury model was established in mice with superior mesenteric artery occlusion, and Caco2 cells were subjected to H/R for the simulation of I/R in vivo.RESULTSThe results suggested that CFTR overexpression significantly increased the Caco2 cell viability and decreased cell apoptosis induced by the H/R. Interestingly, we found that the translocation of p65, an NF-κB member, from the cytoplasm to the nucleus after H/R treatment can be reversed by the overexpression of CFTR, the NF-κB P65 would return from the nucleus to the cytoplasm as determined by immunostaining. We also discovered that CFTR inhibited cell apoptosis in the H/R-treated cells, and this effect was significantly curbed by the NF-κB activator BA, AKT inhibitor GSK690693 and the PI3K inhibitor LY294002. Moreover, we demonstrated that CFTR overexpression could reverse the decreased PI3K/AKT expression induced by the I/R treatment in vivo or H/R treatment in vitro.CONCLUSIONThe results of the present study indicate that the overexpression of CFTR protects Caco2 cells from H/R-induced apoptosis; furthermore, it also inhibits H/R-induced apoptosis through the PI3K/AKT/NF-κB signaling pathway in H/R-treated Caco2 cells and intestinal tissues.

Somatostatin attenuates intestinal epithelial barrier injury during acute intestinal ischemia–reperfusion through Tollip/Myeloiddifferentiationfactor 88/Nuclear factor kappa-B signaling

ABSTRACT In the process of ischemia–reperfusion injury, intestinal ischemia and inflammation interweave, leading to tissue damage or necrosis. However, oxygen radicals and inflammatory mediators produced after reperfusion cause tissue damage again, resulting in severe intestinal epithelial barrier dysfunction. The aim of this study was to determine the protective effect of somatostatin on intestinal epithelial barrier function during intestinal ischemia–reperfusion injury and explore its mechanism. By establishing a rat intestinal ischemia–reperfusion model, pretreating the rats with somatostatin, and then detecting the histopathological changes, intestinal permeability and expression of tight junction proteins in intestinal tissues, the protective effect of somatostatin on the intestinal epithelial barrier was measured in vivo. The mechanism was determined in interferon γ (IFN-γ)-treated Caco-2 cells in vitro. The results showed that somatostatin could ameliorate ischemia–reperfusion-induced intestinal epithelial barrier dysfunction and protect Caco-2 cells against IFN-γ-induced decreases in tight junction protein expression and increases in monolayer cell permeability. The expression of Tollip was upregulated by somatostatin both in ischemia–reperfusion rats and IFN-γ-treated Caco-2 cells, while the activation of TLR2/MyD88/NF-κB signaling was inhibited by somatostatin. Tollip inhibition reversed the protective effect of somatostatin on the intestinal epithelial barrier. In conclusion, somatostatin could attenuate ischemia–reperfusion-induced intestinal epithelial barrier injury by inhibiting the activation of TLR2/MyD88/NF-κB signaling through upregulation of Tollip.

Application of Pressurized Liquid Extractions to Obtain Bioactive Compounds from Tuber aestivum and Terfezia claveryi

A PLE (pressurized liquid extraction) method was adjusted following a full-factorial experimental design to obtain bioactive-enriched fractions from Tuber aestivum and Terfezia claveryi. Temperature, time and solvent (water, ethanol and ethanol–water 1:1) parameters were investigated. The response variables investigated were: obtained yield and the levels of total carbohydrate (compounds, β-glucans, chitin, proteins, phenolic compounds and sterols). Principal component analysis indicated water solvent and high temperatures as more adequate parameters to extract polysaccharide-rich fractions (up to 68% of content), whereas ethanol was more suitable to extract fungal sterols (up to 12.5% of content). The fractions obtained at optimal conditions (16.7 MPa, 180 °C, 30 min) were able to protect Caco2 cells from free radical exposure, acting as antioxidants, and were able to reduce secretion of pro-inflammatory cytokines in vitro: IL-6 (50%), and TNFα (80% only T. claveryi ethanol extract), as well as reduce high inhibitory activity (T. aestivum IC50: 9.44 mG/mL).

Protective effects of syringic acid on inflammation, apoptosis and intestinal barrier function in Caco-2 cells following oxygen-glucose deprivation/reoxygenation-induced injury.

Syringic acid (SA) is an abundant phenolic acid compound that has been demonstrated to yield therapeutic benefits in myocardial and renal ischemia/reperfusion (I/R). However, the role of SA in intestinal I/R injury is unclear. Thus, the present study aimed to investigate the protective effect of SA against intestinal I/R injury. Caco-2 cells were incubated with different doses of SA before oxygen-glucose deprivation/reoxygenation (OGD/R) induction. The viability of Caco-2 cells, the activity of lactate dehydrogenase (LDH), the production of pro-inflammatory cytokines and the levels of reactive oxygen species, superoxide dismutase and malondialdehyde were measured. Apoptosis was evaluated using a TUNEL assay and western blotting. Transepithelial electrical resistance and western blotting were performed to evaluate intestinal barrier function in Caco-2 cells. The present study revealed that pretreatment with SA significantly increased cell viability and reduced LDH release in Caco-2 cells subjected to OGD/R treatment. In addition, SA suppressed OGD/R-induced inflammatory responses by reducing pro-inflammatory cytokine levels. Furthermore, the levels of oxidative stress and apoptosis were ameliorated by SA. SA also alleviated the intestinal barrier disruption exhibited by Caco-2 cells after OGD/R injury. Overall, the present study revealed that SA may potentially protect Caco-2 cells from OGD/R injury, and that this effect may be attributed to its anti-inflammatory and anti-apoptotic activities, as well as its ability to protect the function of the intestinal barrier.

Brown marine algae Gongolaria baccata extract protects Caco-2 cells from oxidative stress induced by tert-butyl hydroperoxide

Gongolaria baccata (S.G. Gmelin) is marine brown seaweed mainly found on the coasts of the Baltic Sea south to the Mediterranean Sea, Canary Islands, Mauritania and Western Sahara. Herein, we report the cell viability and protective effects attributed to molecular mechanisms underlying antioxidant response to survive oxidative stress injuries. Caco-2 cells were submitted to oxidative stress by treatment with tert-butylhydroperoxide (tert-BOOH). The extract prevented cell damage and enhanced activity of antioxidant defenses (NQO1 and GST activities and GSH levels) reduced by treatment with tert-BOOH. The increases of MDA levels, the amount of intracellular ROS and caspase 3/7 activity induced by tert-BOOH were prevented when cells were treated with the G. baccata extract. Moreover, G. baccata extract caused up-regulation of GSTM2, Nrf2, and AKT1 gene expressions, as well as G. baccata extract reduced significantly Bax, BNIP3, APAF1, ERK1, JNK1, MAPK1, P38, P53, NFκB1, TNFα, IL-6, IL-1β and HO-1 gene expressions related to apoptosis, proinflammation and oxidative stress induced by tert-BOOH. These results suggest that G.baccata extract protected the cells against oxidative damage and inflammation; protective effects that could be linked to their bioactive constituents. Hence, this brown seaweed G.baccata extract could be used for the development of functional foods and/or nutraceuticals.

Inhibitory effect of different chicken-derived lactic acid bacteria isolates on drug resistant Salmonella SE47 isolated from eggs.

Lactic Acid Bacteria (LAB) regulate and maintain the stability of healthy microbial flora, inhibit the adhesion of pathogenic bacteria and promote the colonization of beneficial micro-organisms. The drug resistance and pathogenicity of Salmonella enteritis SE47 isolated from retail eggs were investigated. Meanwhile, Enterococcus faecalis L76 and Lactobacillus salivarius LAB35 were isolated from intestine of chicken. With SE47 as indicator bacteria, the diameters of L76 and LAB35 inhibition zones were 12mm and 8·5mm, respectively, by agar inhibition circle method, which indicated that both of them had inhibitory effect on Salmonella, and L76 had better antibacterial effect; two chicken-derived lactic acid bacteria isolates and Salmonella SE47 were incubated with Caco-2. The adhesion index of L76 was 17·5%, which was much higher than that of LAB35 (10·21%) and SE47 (4·89%), this experiment shows that the higher the bacteriostatic effect of potential probiotics, the stronger the adhesion ability; then Caco-2 cells were incubated with different bacteria, and the survival of Caco-2 cells was observed by flow cytometry. Compared with Salmonella SE47, the results showed that lactic acid bacteria isolates could effectively protect Caco-2 cells; finally, after different bacteria incubated Caco-2 cells, according to the cytokine detection kit, the RNA of Caco-2 cells was extracted and transcribed into cDNA, then detected by fluorescence quantitative PCR, the results showed that L76 could protect Caco-2 cells from the invasion of Salmonella SE47, with less cell membrane rupture and lower expression of MIF and TNF genes. Therefore, the lactic acid bacteria isolates can effectively inhibit the adhesion of Salmonella and protect the integrity of intestinal barrier.

Effect of catechin on dietary AGEs absorption and cytotoxicity in Caco-2 cells

Maillard reaction produces advanced glycation end products (AGEs) that endanger human health. This study investigated the protective effect of (+)-catechin (CC) on different types of dietary AGEs absorption and cytotoxicity in Caco-2 cells. Our results showed that CC had higher inhibitory rate on peptide bound-AGEs absorption than free Nɛ-carboxymethyl lysine (CML), which dropped to 36.24% and 32.21% when treated with 20 and 50 μM CC. The reasons might be that CC could repair the loose tight junction (ZO-1) and down-regulation of protein-coupling peptide carrier 1 (PEPT-1) expression in Caco-2 cells which were in accordance with molecular docking results. Additionally, CC could remarkably decreased the protein levels of receptor of AGEs (RAGE), mitogen-activated protein kinases (MAPK) and nuclear factor-kappa B (NF-κB) that detected by western blotting and immunohistochemical staining method. Taken together, these findings demonstrated that CC may inhibit AGEs absorption and protected Caco-2 cells against RAGE-MAPK-NF-κB signaling suppression.

Quercetin Oxidation Metabolite Present in Onion Peel Protects Caco-2 Cells against the Oxidative Stress, NF-kB Activation, and Loss of Epithelial Barrier Function Induced by NSAIDs.

The potential of 2-(3,4-dihydroxybenzoyl)-2,4,6-trihydroxy-3(2H)-benzofuranone (BZF), a quercetin oxidation metabolite, and that of a BZF-rich onion peel aqueous extract (OAE) to protect Caco-2 monolayers against the oxidative stress (OS) and an increased permeability (IP) induced by five nonsteroidal anti-inflammatory drugs (NSAIDs) (indomethacin, diclofenac, piroxicam, ibuprofen, and metamizole) were investigated. Under identical OS conditions, the NSAIDs substantially differed in their ability to induce an IP and/or NF-kB activation. The OAE (100 nM BZF) protected in identical magnitude (84-86%) against OS but in a highly dissimilar manner against the IP (18-73%). While all NSAIDs activated NF-kB, the OAE prevented only that induced by indomethacin. Results reveal that the IP has no direct relationship with the OS and that with the exception of indomethacin, the prevention of NSAIDs-induced OS and/or NF-kB activation plays no fundamental role in the IP-protecting effect of OAE. These results warrant the in vivo evaluation of OAE against indomethacin-induced loss of intestinal barrier function.

Maternally expressed 3 protects the intestinal barrier from cardiac arrest-induced ischemia/reperfusion injury via miR-34a-3p/sirtuin 1/nuclear factor kappa B signaling.

BackgroundCardiac arrest (CA), a common disease with a high mortality rate, is a leading cause of ischemia/reperfusion (I/R)-induced dysfunction of the intestinal barrier. Long non-coding RNAs (lncRNAs) play crucial roles in multiple pathological processes. However, the effect of the lncRNA maternally expressed 3 (MEG3) on intestinal I/R injury and the intestinal barrier has not been fully determined. Therefore, this study aimed to investigate the function of MEG3 in CA-induced intestinal barrier dysfunction.MethodsThe oxygen and glucose deprivation (OGD) model in the human colorectal adenocarcinoma Caco-2 cells and in vivo cardiac arrest-induced intestinal barrier dysfunction model in Sprague-Dawley (SD) rats were established. The effect and underlying mechanism of MEG3 on the intestinal barrier from cardiac arrest-induced ischemia/reperfusion injury were analyzed by methyl thiazolyl tetrazolium (MTT) assays, Annexin V-FITC/PI apoptosis detection kit, Terminal deoxynucleotidyl transferase-mediated dUTP nick end labelling (TUNEL) staining, quantitative polymerase chain reaction (qPCR) assays, Western blot analysis, luciferase reporter gene assays, transepithelial electrical resistance (TEER) measurements, immunofluorescence analysis, and enzyme-linked immunosorbent assay (ELISA) assays.ResultsInterestingly, we found that MEG3 could protect Caco-2 cells from oxygen-glucose deprivation (OGD)/reoxygenation-induced I/R injury by modulating cell proliferation and apoptosis. Moreover, MEG3 relieved OGD-induced intestinal barrier dysfunction in vitro, as demonstrated by its significant rescue effect on transepithelial electrical resistance and the expression of tight junction proteins such as occludin and claudin-1 (CLDN1), which were impaired in OGD-treated Caco-2 cells. Mechanistically, MEG3 inhibited the expression of inflammatory factors including interleukin (IL)-1β, tumor necrosis factor (TNF)-α, interferon-gamma (IFN)-γ, inflammatory factors including interleukin (IL)-10, and transforming growth factor beta (TGFb)-1, as well as nuclear factor-kappa B (NF-κB) signaling. In response to OGD treatment in vitro, MEG3 also activated the expression of sirtuin 1 (SIRT1) by Caco-2 cells via sponging miR-34a-3p. Furthermore, MEG3 relieved CA-induced intestinal barrier dysfunction through NF-κB signaling in vivo.ConclusionsLncRNA MEG3 can protect the intestinal barrier from cardiac arrest-induced I/R injury via miR-34a-3p/SIRT1/NF-κB signaling. This finding provides new insight into the mechanism by which MEG3 restores intestinal barrier function following I/R injury, presenting it as a potential therapeutic candidate or strategy in intestinal injury.

Effect of lotus seedpod oligomeric procyanidins on AGEs formation in simulated gastrointestinal tract and cytotoxicity in Caco-2 cells.

This study explored the effects of lotus seedpod oligomeric procyanidins (LSOPC) and their main monomer catechin (CC) on the formation of advanced glycation end products (AGEs) and Caco-2 cytotoxicity during gastrointestinal digestion. Studies have found that LSOPC and CC inhibited the AGEs formation effectively in simulated gastrointestinal digestion and protected Caco-2 cells from AGEs attack. The effect of CC on the inhibition of AGEs formation was significantly better than that of LSOPC. Further, they could effectively inhibit the digestive enzyme activity, reactive oxygen species, RAGE-p38MAPK-NF-κB signaling pathway, inflammatory factors (tumor necrosis factor alpha, interleukin 6), and adhesion factors (intercellular cell adhesion molecule-1, vascular cell adhesion molecule-1) to protect Caco-2 cells.

Screening and Comparison of Anti-Intestinal Inflammatory Activities of Three Polysaccharides from the Mycelium of Lion's Mane Culinary-Medicinal Mushroom, Hericium erinaceus (Agaricomycetes).

Three major polysaccharides (wHEP-1, wHEP-2, and wHEP-3) were isolated from the mycelium of Hericium erinaceus. This study assessed their chemical and physical properties, molecular weight, monosaccharide compositions, and anti-ulcerative colitis ability to protect Caco-2 cells from lipopolysaccharide (LPS)-induced inflammation. The results showed that the average molecular weight of wHEP-1, wHEP-2, and wHEP-3 was 5010, 1812, and 1118 Da, respectively. wHEP-1 was composed of mannose, glucose, and galactose in a molar ratio of 1.2:16.9:1:1, whereas wHEP-2 and wHEP-3 were composed of glucose and galactose in different molar ratios. Anti-inflammatory activity was compared using LPS-induced Caco-2 cells and a rat model. wHEP-1 exhibited the best anti-inflammatory activity. Thus, the polysaccharide from H. erinaceus as a natural material shows potential for the development of alternative therapies.