Protective Effects of Selenium Nanoparticles against Bisphenol A-Induced Toxicity in Porcine Intestinal Epithelial Cells.

Bisphenol A (BPA) is widely used to harden plastics and polycarbonates and causes serious toxic effects in multiple organs, including the intestines. Selenium, as an essential nutrient element for humans and animals, exhibits a predominant effect in various physiological processes. Selenium nanoparticles have attracted more and more attention due to their outstanding biological activity and biosafety. We prepared chitosan-coated selenium nanoparticles (SeNPs) and further compared the protective effects, and investigated the underlying mechanism of SeNPs and inorganic selenium (Na2SeO3) on BPA-induced toxicity in porcine intestinal epithelial cells (IPEC-J2). The particle size, zeta potential, and microstructure of SeNPs were detected by using a nano-selenium particle size meter and a transmission electron microscope. IPEC-J2 cells were exposed to BPA alone or simultaneously exposed to BPA and SeNPs or Na2SeO3. The CCK8 assay was performed to screen the optimal concentration of BPA exposure and the optimal concentration of SeNPs and Na2SeO3 treatment. The apoptosis rate was detected by flow cytometry. Real-time PCR and Western blot methods were used to analyze the mRNA and protein expression of factors related to tight junctions, apoptosis, inflammatory responses and endoplasmic reticulum stress. Increased death and morphological damage were observed after BPA exposure, and these increases were attenuated by SeNPs and Na2SeO3 treatment. BPA exposure disturbed the tight junction function involved with decreased expression of tight junction protein Zonula occludens 1 (ZO-1), occludin, and claudin-1 proteins. Proinflammatory response mediated by the transcription factor nuclear factor-k-gene binding (NF-κB), such as elevated levels of interleukin-1ß(IL-1ß), interleukin-6 (IL-6), interferon-γ (IFN-γ), interleukin-17 (IL-17), and tumor necrosis factor-α (TNF-α) expression was induced at 6 and 24 h after BPA exposure. BPA exposure also disturbed the oxidant/antioxidant status and led to oxidative stress. IPEC-J2 cell apoptosis was induced by BPA exposure, as indicated by increased BCL-2-associated X protein (Bax), caspase 3, caspase 8, and caspase 9 expression and decreased B-cell lymphoma-2 (Bcl-2) and Bcl-xl expression. BPA exposure activated the endoplasmic reticulum stress (ERS) mediated by the receptor protein kinase receptor-like endoplasmic reticulum kinase (PERK), Inositol requiring enzyme 1 (IRE1α), and activating transcription factor 6 (ATF6). We found that treatment with SeNPs and Na2SeO3 can alleviate the intestinal damage caused by BPA. SeNPs were superior to Na2SeO3 and counteracted BPA-induced tight junction function injury, proinflammatory response, oxidative stress, apoptosis, and ERS stress. Our findings suggest that SeNPs protect intestinal epithelial cells from BPA-induced damage, partly through inhibiting ER stress activation and subsequently attenuating proinflammatory responses and oxidative stress and suppressing apoptosis, thus enhancing the intestinal epithelial barrier function. Our data indicate that selenium nanoparticles may represent an effective and reliable tool for preventing BPA toxicity in animals and humans.

Jianpi Yangzheng decoction suppresses gastric cancer progression via modulating the miR-448/CLDN18.2 mediated YAP/TAZ signaling.

ETHNOPHARMACOLOGICAL RELEVANCE: Developing complementary and effective drugs with less toxicity is urgent for gastric cancer (GC) therapy. Jianpi Yangzheng Decoction (JPYZ) is a curative medical plants formula against GC in clinic while its molecular mechanism remains to be further elucidated. AIM OF THE STUDY: To evaluate the in vitro and in vivo anticancer efficacy of JPYZ against GC and its potential mechanisms. MATERIALS AND METHODS: The effect of JPYZ on regulating the candidate targets were screened and examined by RNA-Seq, qRT-PCR, luciferase reporter assay, and immunoblotting. Rescue experiment was conducted to authenticate the regulation of JPYZ on the target gene. Molecular interaction, intracellular localization and function of target genes were elucidated via Co-IP and cytoplasmic-nuclear fractionation. The impact of JPYZ on the abundance of target gene in clinical specimens of GC patients was evaluated by IHC. RESULTS: JPYZ treatment suppressed the proliferation and metastasis of GC cells. RNA seq revealed JPYZ significantly downregulated miR-448. A reporter plasmid containing CLDN18 3'-UTR WT exhibited significant decrease in luciferase activity when co-transfected with miR-448 mimic in GC cells. CLDN18.2 deficiency promoted the proliferation and metastasis of GC cells in vitro, as well as intensified the growth of GC xenograft in mice. JPYZ reduced the proliferation and metastasis of GC cells with CLDN18.2 abrogation. Mechanically, suppressed activities of transcriptional coactivator YAP/TAZ and its downstream targets were observed in GC cells with CLDN18.2 overexpression and those under JPYZ treatment, leading to cytoplasmic retention of phosphorylated YAP at site Ser-127. High abundance of CLDN18.2 was detected in more GC patients who received chemotherapy combined with JPYZ. CONCLUSION: JPYZ has an inhibitory effect on GC growth and metastasis partly by elevating CLDN18.2 abundance in GC cells, indicating more patients may benefit from combination therapy of JPYZ and the upcoming CLDN18.2 target agents.

Kidney stones, hypercalciuria, and recent insights into proximal tubule calcium reabsorption.

PURPOSE OF REVIEW: Most kidney stones are composed of calcium, and the greatest risk factor for kidney stone formation is hypercalciuria. Patients who form kidney stones often have reduced calcium reabsorption from the proximal tubule, and increasing this reabsorption is a goal of some dietary and pharmacological treatment strategies to prevent kidney stone recurrence. However, until recently, little was known about the molecular mechanism that mediates calcium reabsorption from the proximal tubule. This review summarizes newly uncovered key insights and discusses how they may inform the treatment of kidney stone formers. RECENT FINDINGS: Studies examining claudin-2 and claudin-12 single and double knockout mice, combined with cell culture models, support complementary independent roles for these tight junction proteins in contributing paracellular calcium permeability to the proximal tubule. Moreover, a family with a coding variation in claudin-2 causing hypercalciuria and kidney stones have been reported, and reanalysis of Genome Wide Association Study (GWAS) data demonstrates an association between noncoding variations in CLDN2 and kidney stone formation. SUMMARY: The current work begins to delineate the molecular mechanisms whereby calcium is reabsorbed from the proximal tubule and suggests a role for altered claudin-2 mediated calcium reabsorption in the pathogenesis of hypercalciuria and kidney stone formation.

The traditional Chinese medicine Qiangjing tablet prevents blood-testis barrier injury induced by CdCl2 through the PI3K/Akt/Rictor signaling pathway.

OBJECTIVE: Environmental contaminants such as cadmium (Cd) may have a deleterious impact on sperm and reduce male fertility by compromising the blood-testis barrier (BTB). Hence, the effects of the traditional Chinese medicine Qiangjing tablet (QJP) on sperm quality and BTB alterations induced by Cd in mouse testes were examined. METHODS: Adult KM mice challenged with Cd chloride were examined, QJP was administered to mice as an oral drug by gavage, and the experiments lasted 2 weeks. Testicular and epididymal weights, sperm quality, anti-sperm antibodies (AsAb), hormone levels, and histology were evaluated. Changes in the levels of N-cadherin, occludin, ZO-1, claudin-11, F-actin, and ß-tubulin and their mRNAs were evaluated. The effects of QJP on the PI3K/Akt/Rictor pathway were evaluated. RESULTS: CdCl2 decreased reproductive organ weight, sperm quality, and testosterone (T) levels; increased AsAb, follicle-stimulating hormone (FSH), and luteinizing hormone (LH) levels; induced structural damage in testicles with BTB disruption; increased BTB permeability; and decreased N-cadherin, occludin, ZO-1, claudin-11, F-actin, and ß-tubulin expression. After treatment, QJP blocked the effects of Cd on reproductive organ weight, sperm quality, and T; mitigated germinal epithelium compartment alterations; decreased AsAb, FSH, and LH levels; and preserved BTB ultrastructure and function. In addition, QJP induced increases in N-cadherin, occludin, ZO-1, claudin-11, F-actin, and ß-tubulin levels and the expression of their mRNAs through the PI3K/Akt/Rictor pathway. After the application of JRAB2011, the levels of a specific mTORC2 suppressor, Rictor, and the BTB-protective effect of QJP were greatly reduced. CONCLUSIONS: We demonstrated the effect of QJP against Cd-induced damage to the BTB, and the results indicate that QJP may play a significant role in opposing the effects of Cd through the PI3K/Akt/Rictor pathway.

High-frequency electroacupuncture improves endometrial receptivity via regulating cell adhesion molecules and leukemia inhibitory factor / signal transducer and activator of transcription signaling pathway.

Controlled ovarian hyperstimulation (COH) impairs the endometrium receptivity during the implantation window, resulting in a lower clinical pregnancy rate and a higher abortion rate. Our study explored the effect of electroacupuncture on the endometrial receptivity of COH rats. Female rats were randomly divided into normal treatment (Normal), model treatment (Model), low-frequency electroacupuncture treatment (LF-EA) and high-frequency electroacupuncture treatment (HF-EA). Rats in the Model, LF-EA, and HF-EA treatment groups were injected with pregnant mare serum gonadotropin (PMSG) and human chorionic gonadotropin (HCG) to establish a model of COH rats. Compared with the Normal, the endometrial thickness, the number of pinopodes and amount of blastocyst implantation in the Model group were significantly reduced. Among them, the endometrial thickness and the amount of blastocyst implantation in the Model group were substantially decreased than those in the HF-EA group. High-frequency electroacupuncture treatment could markedly reduce the protein expression levels of E-cadherin, ß-catenin and claudin-1 (CLDN1). During HF-EA treatment, the LIF/STAT3 signaling pathway of COH rats was enhanced. In conclusion, electroacupuncture could improve the endometrium receptivity and promote the blastocyst implantation in COH rats by reducing cell adhesion molecules and enhancing the LIF/STAT3 signaling pathway.Highlights High-frequency electroacupuncture could effectively improve endometrial receptivity and blastocyst implantation amount in COH rats.Electroacupuncture, especially high-frequency electroacupuncture, could significantly increase endometrial thickness and the number of pinopodes.High-frequency electroacupuncture significantly reduced the protein expression levels of E-cadherin, ß-catenin and CLDN1 adhesion molecules in COH rats.High-frequency electroacupuncture could markedly enhance the LIF/STAT3 signaling pathway in COH rats.

AMPA Receptor Auxiliary Subunit GSG1L Suppresses Short-Term Facilitation in Corticothalamic Synapses and Determines Seizure Susceptibility.

The anterior thalamus (AT) is critical for memory formation, processing navigational information, and seizure initiation. However, the molecular mechanisms that regulate synaptic function of AT neurons remain largely unexplored. We report that AMPA receptor auxiliary subunit GSG1L controls short-term plasticity in AT synapses that receive inputs from the cortex, but not in those receiving inputs from other pathways. A canonical auxiliary subunit stargazin co-exists in these neurons but is functionally absent from corticothalamic synapses. In GSG1L knockout mice, AT neurons exhibit hyperexcitability and the animals have increased susceptibility to seizures, consistent with a negative regulatory role of GSG1L. We hypothesize that negative regulation of synaptic function by GSG1L plays a critical role in maintaining optimal excitation in the AT.

Nobiletin Attenuates DSS-Induced Intestinal Barrier Damage through the HNF4α-Claudin-7 Signaling Pathway.

The intestinal epithelium barrier functions to protect human bodies from damages such as harmful microorganisms, antigens, and toxins. In this study, we evaluated the protective effect and molecular mechanism of a dominant polymethoxyflavone nobiletin (NOB) from tangerine peels on intestinal epithelial integrity. The results from transepithelial electrical resistance (TEER) suggested that NOB pretreatment counteracts epithelial injury induced by inflammatory cytokines (TEER value in 48 h: vehicle, 135.6 ± 3.9 Ω/cm2; TNF-α + IL-1ß, 90.7 ± 0.5 Ω/cm2; 10 µM NOB + TNF-α + IL-1ß, 126.1 ± 0.8 Ω/cm2; 100 µM NOB + TNF-α + IL-1ß, 125.3 ± 0.5 Ω/cm2. P < 0.001). Clinical and pathological test results suggested that administration of NOB effectively alleviates intestinal barrier injury induced by dextran sulfate sodium (DSS) as evidenced by the length of colon villi on day 7 (control, 253.7 ± 4.8 µm, DSS 131.6 ± 4.6 µm, NOB + DSS, 234.5 ± 5.1 µm. P < 0.001). Interestingly, when screening tight junction molecules for intestinal barrier integrity, we observed that independent treatment with NOB sharply increased claudin-7 levels (ratio of claudin-7 over GAPDH: control, 1.0 ± 0.06; DSS, 0.02 ± 0.001; NOB + DSS, 0.3 ± 0.07. P < 0.001), which was previously suppressed upon DSS stimulation. Furthermore, hepatocyte nuclear factor 4α (HNF-4α) transcriptional regulation of claudin-7 contributed to intestinal barrier homeostasis. Therefore, our study suggests potential intestinal protective strategies based on polymethoxyflavones of aged tangerine peels.

Vitamin D strengthens the bladder epithelial barrier by inducing tight junction proteins during E. coli urinary tract infection.

Tight junction proteins are pivotal to prevent bacterial invasion of the epithelial barrier. We here report that supplementation with vitamin D can strengthen the urinary bladder lining. Vitamin D deficient and sufficient mice were infected with Escherichia coli (E. coli) transurethrally to cause urinary tract infection. In addition, bladder biopsies were obtained from postmenopausal women before and after a 3-month period of supplementation with 25-hydroxyvitamin D3 (25D3) and ex vivo infected with E. coli. In biopsies, obtained before E. coli infection, vitamin D had no impact on tight junction proteins. However, during E. coli infection, vitamin D induced occludin and claudin-14 in mature superficial umbrella cells of the urinary bladder, as demonstrated by immunohistochemistry. Increased cell-cell adhesion consolidating the epithelial integrity is thereby promoted. We here describe a novel role of vitamin D in the urinary tract supporting vitamin D supplementation to restore the bladder epithelial integrity.

Flavonol glycosides of Rosa multiflora regulates intestinal barrier function through inhibiting claudin expression in differentiated Caco-2 cells.

Eijitsu, the fruits of Rosa multiflora Thunberg, is a traditional Japanese natural medicine and used as purgatives. The active constituents were identified as flavonol glycosides, multiflorin A (MF), and multinoside A (MSA), but mechanism of the purgative action is still unknown. We hypothesized that the flavonol glycosides 1 and 2 may exhibit the purgative actions through modulating intestinal epithelial barrier function. Then, this study aimed to investigate their effects on intestinal epithelial barrier function and possible molecular mechanisms in human intestinal Caco-2 cells. MF and MSA decreased transepithelial electrical resistance and increased paracellular permeability of Caco-2 cell monolayers. Expression of claudins (CLDNs) involved in paracellular permeability of ions and low-molecular substances was significantly decreased by the treatment with MF or MSA. The compounds increased the ratio of N-cadherin/E-cadherin, expression of transforming growth factor-ß and Slug, and phosphorylation level of Smad3, suggesting epithelial-mesenchymal transition activation, and epithelial-mesenchymal transition inhibition by transforming growth factor-ß receptor kinase inhibitors completely recovered the decreased CLDNs expression caused by MF and MSA. Moreover, the increased paracellular permeability and the decreased CLDNs expression by the treatment with MF or MSA for 24 hours recovered to the same extent as the untreated group with the compounds by continuous culture in the growth medium alone for 48 hours. These results suggest that Eijitsu may be effective in preventing or relieving constipation symptoms, unless used chronically.

Long noncoding RNA DDX11-AS1 induced by YY1 accelerates colorectal cancer progression through targeting miR-873/CLDN7 axis.

OBJECTIVE: Increasing studies have confirmed long non-coding RNAs (lncRNAs) as novel regulators in tumorigenesis. LncRNA DDX11 antisense RNA 1 (DDX11-AS1) has been found to be abnormally expressed in several tumors. In this work, we aimed to evaluate its expressions and functions in colorectal cancer (CRC). PATIENTS AND METHODS: The Cancer Genome Atlas (TCGA) datasets were used for the identification of dysregulated lncRNA in CRC. The levels of DDX11-AS1 were determined in tumor tissues and cell lines by Real Time-Polymerase Chain Reaction (RT-PCR). The clinical significance of DDX11-AS1 in CRC patients was analyzed using Chi-square test and Kaplan-Meier analysis. Functional assays for the exploration of DDX11-AS1 and miR-873 were performed using a series of cells experiment. ChIP assay and luciferase reporter assays were used to explore the mechanism of actions of DDX11-AS1 in CRC cells. RESULTS: We identified DDX11-AS1 as a new CRC-related lncRNA whose levels were distinctly up-regulated in CRC specimens and cell lines, partly induced by YY1. Clinical explorations suggested that increased expressions of DDX11-AS1 in CRC were positively associated with lymph nodes metastasis and TNM stage and had a distinct influence on the overall survival. Further multivariate assays indicated that DDX11-AS1 was an independent prognostic parameter implying a poorer clinical outcome for patients with CRC. Functional assays revealed that the knockdown of DDX11-AS1 suppressed the proliferation, migration, and invasion of CRC cells, and stimulate apoptosis. Mechanistic studies showed that the up-regulation of DDX11-AS1 competitively bound to miR-873 prevented CLDN7 from miRNAs-mediated degradations, thus facilitated the CRC progress. Further rescue assays were carried out to achieve confirmation. CONCLUSIONS: Our present findings may enhance our understanding of the pathogenesis of CRC and revealed DDX11-AS11 as a potential therapeutic target for CRC.

Coffee prevents fatty liver disease induced by a high-fat diet by modulating pathways of the gut-liver axis.

Coffee consumption is inversely associated with the risk of non-alcoholic fatty liver disease (NAFLD). A gap in the literature still exists concerning the intestinal mechanisms that are involved in the protective effect of coffee consumption towards NAFLD. In this study, twenty-four C57BL/6J mice were divided into three groups each receiving a standard diet, a high-fat diet (HFD) or an HFD plus decaffeinated coffee (HFD+COFFEE) for 12 weeks. Coffee supplementation reduced HFD-induced liver macrovesicular steatosis (P < 0·01) and serum cholesterol (P < 0·001), alanine aminotransferase and glucose (P < 0·05). Accordingly, liver PPAR- α (P < 0·05) and acyl-CoA oxidase-1 (P < 0·05) as well as duodenal ATP-binding cassette (ABC) subfamily A1 (ABCA1) and subfamily G1 (ABCG1) (P < 0·05) mRNA expressions increased with coffee consumption. Compared with HFD animals, HFD+COFFEE mice had more undigested lipids in the caecal content and higher free fatty acid receptor-1 mRNA expression in the duodenum and colon. Furthermore, they showed an up-regulation of duodenal and colonic zonulin-1 (P < 0·05), duodenal claudin (P < 0·05) and duodenal peptide YY (P < 0·05) mRNA as well as a higher abundance of Alcaligenaceae in the faeces (P < 0·05). HFD+COFFEE mice had an energy intake comparable with HFD-fed mice but starting from the eighth intervention week they gained significantly less weight over time. Data altogether showed that coffee supplementation prevented HFD-induced NAFLD in mice by reducing hepatic fat deposition and metabolic derangement through modification of pathways underpinning liver fat oxidation, intestinal cholesterol efflux, energy metabolism and gut permeability. The hepatic and metabolic benefits induced by coffee were accompanied by changes in the gut microbiota.

Gushukang exerts osteopreserve effects by regulating vitamin D and calcium metabolism in ovariectomized mice.

Calcium homeostasis plays vital roles in the management of bone health. Traditional herbal formula Gushukang (GSK) was clinically applied to treat primary osteoporosis. This study aimed to explore the osteoprotective effects of GSK and its roles in maintaining calcium homeostasis in ovariectomized (OVX) mice. The OVX mice were orally treated with low (0.38 g/kg), middle (0.76 g/kg) and high (1.52 g/kg) dose of GSK for 8 weeks. GSK treatment dramatically increased serum calcium level and decreased urinary calcium excretion as well as enhanced calcium content in bone of OVX mice. Serum level of 25-hydroxyvitamin D was significantly increased in OVX mice with exposure to GSK. Treatment with GSK improved bone mass and micro-structure of trabecular bone at distal metaphysis of femur and proximal metaphysis of tibia in OVX mice shown by safranin O staining and micro-CT measurement. GSK treatment at all doses up-regulated mRNA expression of calcium-binding protein-28k and vitamin D receptor in kidney of OVX mice, and dose-dependently decreased mRNA expression of claudin-14 and elevated mRNA expression of claudin-16 in duodenum of OVX mice. Taken together, GSK exerted beneficial effects on trabecular bone of OVX mice by improving calcium homeostasis via regulating paracellular calcium absorption in duodenum and transcellular calcium reabsorption in kidney.

Dichloromethane Extracts of Geranium Koreanum Kom. Alleviates Esophagus Damage in Acute Reflux Esophagitis-Induced Rats by Anti-Inflammatory Activities.

Reflux esophagitis (RE) is a gastrointestinal disease caused by the reflux of gastric acid and stomach contents, and it leads to esophageal damage. Therefore, it is necessary to study the improvement of esophageal damage on a RE-induced model. The present study was accomplished to demonstrate the protective effects of a dichloromethane fraction of Geranium koreanum (DGK) plant on esophageal damage in an acute RE rat model. First, we examined the potential of anti-inflammatory effects of various fractions measured by cell cytotoxicity, morphological changes and nitric oxide (NO) production on lipopolysaccharide (LPS)-induced Raw 264.7 macrophage cells. Then, to evaluate the protective effects on RE, rats were partitioned into the following groups: normal control, RE-induced control and RE rats pre-treated with DGK 100 and 200 mg/kg body weight. The esophageal mucosal ulcer ratio was measured by the Image J program and histological changes were examined using a hematoxylin and eosin staining of the esophageal mucosa. The expression of pro-inflammatory proteins, cytokines and tight junction proteins involved in the esophageal mucosal damage were investigated using Western blotting and an enzyme-linked immunosorbent assay (ELISA) kit with esophagus tissue. DGK chemical profile and phenolic contents were analyzed by liquid chromatography-mass spectrometry (LC-MS/MS). The results showed that DGK exhibited anti-inflammatory effects against LPS-stimulated cells by significantly inhibiting NO production. Additionally, the results in vivo showed that improvement effects of DGK on esophageal mucosal damage. The expression of inflammatory proteins involved in nuclear factor κB (NF-κB) signaling pathways and tight junction protein (claudin-4 and -5) were significantly decreased in esophageal mucosa. We found the potential of DGK as source of replacement therapy products for inflammatory and RE disease.

Claudin-3 regulates bile canalicular paracellular barrier and cholesterol gallstone core formation in mice.

BACKGROUND & AIMS: Most cholesterol gallstones have a core consisting of inorganic and/or organic calcium salts, although the mechanisms of core formation are poorly understood. We examined whether the paracellular permeability of ions at hepatic tight junctions is involved in the core formation of cholesterol gallstones, with particular interest in the role of phosphate ion, a common food additive and preservative. METHODS: We focused on claudin-3 (Cldn3), a paracellular barrier-forming tight junction protein whose expression in mouse liver decreases with age. Since Cldn3-knockout mice exhibited gallstone diseases, we used them to assess the causal relationship between paracellular phosphate ion permeability and the core formation of cholesterol gallstones. RESULTS: In the liver of Cldn3-knockout mice, the paracellular phosphate ion permeability through hepatic tight junctions was significantly increased, resulting in calcium phosphate core formation. Cholesterol overdose caused cholesterol gallstone disease in these mice. CONCLUSION: We revealed that in the hepatobiliary system, Cldn3 functions as a paracellular barrier for phosphate ions, to help maintain biliary ion homeostasis. We provide in vivo evidence that elevated phosphate ion concentrations play a major role in the lifestyle- and age-related risks of developing cholesterol gallstone disease under cholesterol overdose. LAY SUMMARY: Herein, we reveal a new mechanism for cholesterol gallstone formation, in which increased paracellular phosphate ion permeability across hepatobiliary epithelia causes calcium phosphate core formation and cholesterol gallstones. Thus, altered phosphate ion metabolism under cholesterol overdose plays a major role in the lifestyle- and age-related risks of developing cholesterol gallstone disease.

Dysregulated Bile Transporters and Impaired Tight Junctions During Chronic Liver Injury in Mice.

BACKGROUND & AIMS: Liver fibrosis, hepatocellular necrosis, inflammation, and proliferation of liver progenitor cells are features of chronic liver injury. Mouse models have been used to study the end-stage pathophysiology of chronic liver injury. However, little is known about differences in the mechanisms of liver injury among different mouse models because of our inability to visualize the progression of liver injury in vivo in mice. We developed a method to visualize bile transport and blood-bile barrier (BBlB) integrity in live mice. METHODS: C57BL/6 mice were fed a choline-deficient, ethionine-supplemented (CDE) diet or a diet containing 0.1% 3,5-diethoxycarbonyl-1, 4-dihydrocollidine (DDC) for up to 4 weeks to induce chronic liver injury. We used quantitative liver intravital microscopy (qLIM) for real-time assessment of bile transport and BBlB integrity in the intact livers of the live mice fed the CDE, DDC, or chow (control) diets. Liver tissues were collected from mice and analyzed by histology, immunohistochemistry, real-time polymerase chain reaction, and immunoblots. RESULTS: Mice with liver injury induced by a CDE or a DDC diet had breaches in the BBlB and impaired bile secretion, observed by qLIM compared with control mice. Impaired bile secretion was associated with reduced expression of several tight-junction proteins (claudins 3, 5, and 7) and bile transporters (NTCP, OATP1, BSEP, ABCG5, and ABCG8). A prolonged (2-week) CDE, but not DDC, diet led to re-expression of tight junction proteins and bile transporters, concomitant with the reestablishment of BBlB integrity and bile secretion. CONCLUSIONS: We used qLIM to study chronic liver injury, induced by a choline-deficient or DDC diet, in mice. Progression of chronic liver injury was accompanied by loss of bile transporters and tight junction proteins.

Dietary Supplementation with Oleum Cinnamomi Improves Intestinal Functions in Piglets.

The present study was to determine the efficacy of dietary supplementation with oleum cinnamomi (OCM) on growth performance and intestinal functions in piglets. Sixteen piglets (24-day-old) were randomly assigned to the control or OCM groups. Piglets in the control group were fed a basal diet, whereas piglets in the OCM group were fed the basal diet supplemented with 50 mg/kg OCM. On day 20 of the trial, blood samples and intestinal tissues were obtained from piglets. Compared with the control group, dietary OCM supplementation increased (p < 0.05) average daily feed intake, plasma insulin levels, villus width and villous surface area in the duodenum and jejunum, DNA levels and RNA/DNA ratios in the ileum, the abundance of Enterococcus genus and Lactobacillus genus in caecum digesta, mRNA levels for epithelial growth factor receptor (EGFR), Ras, extracellular signal-regulated kinase 1/2 (Erk1/2), b-cell lymphoma-extra large (Bcl-xL), villin, junctional adhesion molecule A (JAM-A), myxovirus resistance (MX) 1, MX2 and regenerating islet-derived protein 3 gamma (REG3G), and protein abundances of Ras and claudin-1, but decreased (p < 0.05) diarrhoea incidence; the abundances of Enterobacteriaceae family, Enterococcus genus, Lactobacillus genus, Bifidobacterium genus, and Clostrium coccoides in the colon digesta, and AMP-activated protein kinase (AMPK) mRNA levels and caspase-3 protein abundance in the jejunal mucosa of piglets. Taken together, these data indicate that dietary OCM supplementation modulates intestinal microbiota and improves intestinal function in weanling pigs. OCM is an effective feed additive and alternative to feed antibiotics for improving intestinal health in swine.

The effect of fucoidan on intestinal flora and intestinal barrier function in rats with breast cancer.

Recent research studies have shown that the intestinal flora are related to the occurrence and progress of breast cancer. This study investigates the effect of fucoidan on intestinal flora and intestinal barrier function in rats with 7,12-dimethylbenz[a]anthracene (DMBA)-induced breast cancers. Sixty female Sprague-Dawley rats were randomly assigned to the control group, the model group, and the F1 and F2 groups, which were fed fucoidan at concentrations of 200 and 400 mg per kg bw (body weight), respectively. Intestinal histopathological analysis was performed and 16S rDNA high-throughput sequencing was used to provide an overview of the intestinal flora composition. The contents of d-lactic acid (d-LA), diamine oxidase (DAO) and endotoxin in plasma were detected by ELISA. Expression levels of the tight junction (TJ) proteins, phosphorylated p38 MAPK and ERK1/2 were measured using western blotting. Our results suggested that the intestinal wall of the model group was damaged. However, after fucoidan intervention, the villi were gradually restored. ELISA showed that the levels of plasma endotoxin, d-LA and DAO decreased in the F1 and F2 groups compared to those in the model group. Fucoidan treatment also increased the expressions of ZO-1, occludin, claudin-1 and claudin-8. Furthermore, the expression levels of phosphorylated p38 MAPK and ERK1/2 were upregulated in fucoidan treatment groups. The results of 16S rDNA high-throughput sequencing indicated that fucoidan increased the diversity of the intestinal microbiota and induced changes in microbial composition, with the increased Bacteroidetes/Firmicutes phylum ratio. In conclusion, the supplement of fucoidan could improve the fecal microbiota composition and repair the intestinal barrier function. The study suggested the use of fucoidan as an intestinal flora modulator for potential prevention of breast cancer.

Zinc strengthens the jejunal barrier by reversibly tightening the paracellular route.

During the postweaning period, piglets are prone to gastrointestinal infections. The resulting impairment of intestinal barrier function may cause diarrhea associated with growth retardation or even death of piglets. Orally applied Zn is commonly used to prevent and treat diarrhea, but its mode of action still needs to be elucidated. To analyze the molecular mechanism whereby Zn acts on porcine intestinal barrier function, ex vivo studies on piglet jejunum and accompanying in vitro studies on a porcine jejunal epithelial cell line, IPEC-J2/PS, were performed with electrophysiological tools. Feeding pharmacological Zn doses exerted no significant electrophysiologically ascertainable short- and long-term effects on jejunal barrier function ex vivo. However, in IPEC-J2/PS, basolateral Zn was cytotoxic since its application caused a release of lactate dehydrogenase and an irreversible breakdown of the epithelial barrier. In contrast, apical Zn application caused an immediate increase in paracellular resistance and a decrease in permeability to the paracellular marker fluorescein, reflecting overall barrier strengthening in vitro. Apical effects were fully reversible upon washout. This indicates that Zn supplemented to feed was completely washed out during ex vivo jejunum preparation. We conclude that there is no evidence for long-term barrier effects through prophylactic Zn supplementation and that extracellular Zn acts acutely and reversibly from the apical side via tightening the paracellular route, thus counteracting leak-flux diarrhea.NEW & NOTEWORTHY Therapeutically administered Zn successfully treats diarrhea in veterinary and human medicine. Here we present data that Zn strengthens the porcine jejunal epithelial barrier by reversibly tightening the paracellular route for inorganic ions and small solutes. Acute or long-lasting Zn effects on transcellular transport (Cl- secretion) were not detected. We therefore conclude that Zn is useful for acutely treating leak-flux diarrhea rather than secretory diarrhea. Suitability as prophylactic feed supplement, however, is questionable.

Oral administration of propionic acid during lactation enhances the colonic barrier function.

BACKGROUND: Propionic acid is a three-carbon short chain fatty acid (SCFA) that has various effects on colonic functions. Although several studies have shown the effects of propionic acid on intestinal mucosal barrier function, studies of the promotion effect during pre-weaning are rare in the literature as far as we know. METHODS: Pre-weaning male Sprague-Dawley rats 7 days after birth were given an oral 0.2 mL/10 g of 200 mM propionic acid solution in the propionic acid group or normal saline solution in the control group by gavage twice a day for ten days. The proximal colonic contents were used for extraction and determination of propionic acid by gas chromatographic analysis; the transepithelial electrical resistance (TER) of colonic tissue was detected by an Ussing chamber; the alterations of ZO-1, Claudin-1, Claudin-8 and Occludin proteins were analyzed by Western blot and immunohistochemistry; and The activity of ERK and p38 MAPK was determined by the phosphorylation status of ERK1/2 and p38 with Western blot. RESULTS: Our results suggested a higher concentration (23.5 ± 1.9 mmol/kg) of propionic acid compared to the physiological concentration (18.1 ± 0.9 mmol/kg) in colonic contents after oral administration increased the value of TER and the expression of ZO-1, Claudin-1, Claudin-8 and Occludin compared to the control group. Furthermore, the expression levels of phosphorylated ERK1/2 and p38 MAPK were increased in propionic acid group. CONCLUSIONS: We concluded that continuous oral administration of propionic acid during lactation may increase its concentration in the proximal colon and promote epithelial barrier function of proximal colon by enhancing the expression of ZO-1, Claudin-8, Claudin-1 and Occludin via increases in the expression of ERK1/2 and p38 MAPK.

High glucose decreases claudins-5 and -11 in cardiac microvascular endothelial cells: Antagonistic effects of tongxinluo.

Purpose/aim of the study: Claudins-5, -9, and -11 are tight-junction proteins that are mainly expressed in endothelial cells. Their deficiency may lead to cell barrier dysfunction, which is considered as the initiating process and pathological basis of cardiovascular disease in diabetes. We investigated whether high glucose (HG) affects claudins-5, -9, and -11 in human cardiac microvascular endothelial cells (HCMECs), and examined the effects of the traditional Chinese medication tongxinluo (TXL) on these tight junction proteins. MATERIALS AND METHODS: HCMECs were exposed to HG with and without TXL treatment, and then mRNA and protein levels of claudins-5, -9, and -11 were examined. The distribution of claudins-5 and -11 was also investigated. Histone H3K9 acetylation (H3K9ac) in claudin-5 and claudin-11 gene promoters, which functions in transactivation, was measured. RESULTS: We found that HG suppressed claudins-5 and -11 gene expression in HCMECs, and TXL reversed the HG-mediated inhibition of claudins-5 and -11 mRNA and protein expressions. Treatment with high-dose of TXL promoted cell membrane localization of claudins-5 and -11 in HG-stimulated HCMECs. Furthermore, high-dose of TXL blocked the inhibition of H3K9ac in claudin-5 and claudin-11 gene promoters caused by exposure to HG, thus activating gene transcription. CONCLUSIONS: Our results show that HG suppressed claudins-5 and -11 in HCMECs, and TXL could reverse the HG-induced suppression of claudins-5 and -11 by increasing H3K9ac in their respective gene promoters.