Proteins Zonula Occludens-1 Research Articles

Delayed Administration of IGFBP7 Improved Bone Defect Healing via ZO-1 Dependent Vessel Stabilization.

The vascular response following injury is pivotal for successful bone-defect repair but constitutes a major hurdle in the field of regenerative medicine. Throughout this process, vessel stabilization is crucial to provide an adequate nutrient supply and facilitate efficient waste removal. Therefore, this study investigated whether promoting vascular stabilization improves bone defect repair outcomes. The findings show that insulin-like growth factor-binding protein (IGFBP) 7 exhibits a novel biological function in attenuating vascular permeability and enhancing vascular wall integrity. The potential underlying mechanism involves the up-regulation of insulin-like growth factor 1 receptor (IGF1R) expression by IGFBP7 on endothelial cell membrane, followed by activation of the downstream PI3K/AKT signaling pathway and upregulated expression of the tight junction protein zonula occludens-1 (ZO-1). IGFBP7 delayed administration in mice with cranialdefects significantly improved bone defect healing by increasing ZO-1 and CD31 co-localization within vessel walls and optimizing the perfusion function of the final vascular network. Furthermore, the application of the typical tight junction regulator AT1001 effectively promoted ZO-1-dependent vascular stabilization and facilitated bone defect repair. This study presents a new approach to enhance bone defect healing via vascular stabilization-targeted interventions and significantly advances the understanding of the complex interplay between osteogenesis and angiogenesis in bone defect healing.

Bifidobacterium longum JBLC-141 alleviates hypobaric hypoxia-induced intestinal barrier damage by attenuating inflammatory responses and oxidative stress

Hypobaric hypoxia exposure occurs at high altitudes, including plateaus, and affects normal intestinal function and microbiota composition. Exposure induces an intestinal inflammatory response and oxidative stress injury, ultimately disrupting intestinal homeostasis and causing barrier damage. Thus, due to its anti-inflammatory, antioxidative, and intestinal microbiota-regulating properties, Bifidobacterium longum is a potentially effective probiotic intervention to protect the intestinal barrier during low-pressure hypoxia on plateaus. However, its mechanism of action is not fully defined. In this study, we investigate the mechanism by which B. longum intervenes in intestinal barrier damage caused by plateau low-pressure hypoxia. To this end, an in vivo model is established by exposing rats to a simulated low-pressure hypoxic plateau environment. The experimental rats were subsequently supplemented with a B. longum strain (JBLC-141) extracted from the feces of healthy adults in Bama, Guangxi. B. longum JBLC-141 mitigates the effects of plateau low-pressure hypoxia on the rat intestinal barrier. This is achieved by activating the intestinal Kelch-like ECH-associated protein 1 (KEAP1)/nuclear factor erythroid 2-related factor 2 (NRF2) pathway, alleviating plateau hypoxia-induced intestinal oxidative stress injury. B. longum JBLC-141 also attenuates the inflammatory response and upregulates the expression of the tight junction proteins claudin-1, occludin, and zonula occludens-1. Furthermore, it reduces intestinal permeability, effectively ameliorating and repairing the barrier histological damage induced by the plateau low-pressure hypoxic environment. In addition, B. longum JBLC-141 positively regulates the intestinal microbiota, increasing the relative abundance of beneficial bacteria while reducing that of pathogenic bacteria and maintaining intestinal flora homeostasis in rats.

Dietary sanguinarine supplementation improves the growth performance and intestinal immunity of broilers

Dietary sanguinarine (SAN) can enhance the growth performance of poultry and livestock, but the regulatory mechanism of the SAN monomer on intestinal homeostasis and how it promotes growth performance has not yet been clarified. In this study, 200 chickens were divided into four groups and fed different doses of SAN (0, 0.225, 0.75, 2.25mg/kg) for transcriptome and microbiota analysis. The data showed that different doses of SAN supplementation increased the feed conversion rate (FCR) of 22 to 42 d old and 1 to 42 d old broilers (P < 0.01), and 0.225 mg/kg SAN reduced the contents of alanine aminotransferase (ALT), aspartate aminotransferase (AST), creatinine (CREA) and blood urea nitrogen (BUN) in serum (P < 0.01). Dietary SAN increased the villus height and the villus height/crypt depth (V/C) ratio in the ileum (P < 0.01). The levels of tight junction proteins (zonula occludens-1, occludin and claudin-1) were up-regulated in the ileum and cecum (P < 0.01) and the levels of immunoglobulin (Ig) A, IgM, IgG, interleukin (IL)-4, IL-10 and interferon (IFN)-γ were up-regulated in the serum and ileum (P < 0.01). RNA-seq analysis revealed 385 differentially expressed genes (DEGs) (|log2 fold change| ≥ 1, FDR < 0.05) between the SAN group and CON group. Kyoto Encyclopedia of Genes and Genomes pathway analysis showed 15 pathways mostly associated with the immune system. Additionally, the reverse transcription-PCR results showed that the relative mRNA expression of β-defensin and mucin 2 were up-regulated (P < 0.01) and Toll-like receptor (TLR) 2 and TLR 4 mRNA were down-regulated by SAN (P < 0.01), which was consistent with the transcriptomic analysis. Western blot analysis also showed that SAN reduced the expression of inflammatory proteins such as TLR4, nuclear factor-kappa B and IL-1β in the ileum (P < 0.01). In addition, at the genus level, SAN significantly increased the relative abundance of bacteria (Bacteroides, unclassified_f__Lachnospiraceae, Lactobacillus and Romboutsia) involved in acetate and butyrate production in the cecum, which are associated with enhanced intestinal immune function and maintaining intestinal health. In conclusion, SAN ameliorates the growth performance of broilers, enhances intestinal immune function, regulates the structure of microbiota and maintains intestinal health.

Structural characterization of the polysaccharides from Atractylodes chinensis (DC.) Koidz. and the protective effection against alcohol-induced intestinal injury in rats

A neutral polysaccharide, AP, with a weight-average molecular weight of 60.61 kDa, consisting mainly of arabinose and galactose, was isolated from the rhizomes of Atractylodes chinensis (DC.) Koidz. Methylation analyses and nuclear magnetic resonance spectroscopy indicated that the probable repeat unit of AP was →3,6)-α-D-Galp-(1→ residues and constituted the main chain, with a side chain of →5)-α-L-Araf-(1→ and terminal α-L-Araf attached to C-6 of the main chain. The protective activity and potential mechanisms of action of AP on the intestinal tract were investigated. AP improved intestinal oxidative stress injury and inflammatory responses by promoting the nuclear factor erythroid 2-related factor 2/heme oxygenase-1 signaling pathway and inhibiting the toll-like receptor 4/myeloid differentiation primary response protein 88/nuclear factor-kappa B signaling pathway, but also repaired colonic mucosal injury and reduced intestinal leakage of endotoxins by promoting expression of the tight-junction proteins zonula occludens-1 and occludin. AP improved ecological dysregulation of the intestinal microbiota and promoted the growth of the potentially beneficial bacteria Lactobacillus_taiwanensis, Limosilactobacillus_reuteri and Akkermansia_muciniphila. AP promoted intestinal health by increasing the production of potentially beneficial metabolites such as short-chain fatty acids, Indole-3-propionic acid, and N-Eicosapentaenoyl tryptophan through metabolism (amino acids, lipids, carbohydrates). These results suggest that AP is a promising prebiotic in attenuating alcohol-induced intestinal damage.

Dietary supplementation with 25-hydroxyvitamin D3 regulates productive performance, lipid metabolism and gut microbiota in aged laying ducks

The aim of this study was to investigate the effect of dietary supplementation with 25-hydroxyvitamin D3 (25(OH)D3) on productive performance, lipid metabolism and gut microbiota in aged laying ducks. A total of 432 healthy Longyan ducks at 60-week of age were randomly allotted to 6 groups, each with 6 replicates of 12 ducks. Ducks were given a basal diet (without added 25(OH)D3) or that diet supplemented with 800, 1600, 2400, 3200, or 4000 IU/kg 25(OH)D3 for a total of 16 wk. Dietary supplementation with 25(OH)D3 improved egg production, egg mass and average daily feed intake, and decreased the feed conversion ratio (FCR) of ducks during the whole trial period (linear, quadratic; P < 0.05). Supplementation with 25(OH)D3 decreased very low-density lipoprotein (VLDL) content in yolk (P = 0.008), decreased high-density lipoprotein and low-density lipoprotein (LDL) content in plasma (P = 0.002). Hepatic index, VLDL, LDL, triglyceride and total cholesterol content in liver, nonalcoholic fatty liver activity score of liver and alanine aminotransferase content in plasma were decreased with supplementation of 25(OH)D3 (linear or quadratic; P < 0.05). The decreased hepatic apolipoprotein B 100 and lipoprotein lipase expression, and increased hepatic peroxisome proliferator-activated receptor-α and sterol regulatory element binding protein-1 expression resulted from 25(OH)D3 supplementation (linear, quadratic; P < 0.05). Moreover, 25(OH)D3 supplementation increased the villus/crypt ratio (linear, quadratic; P < 0.05) and expression of zonula occludens protein 1 and nuclear factor-κ-gene binding in duodenum (P < 0.05). The supplementation of 25(OH)D3 reduced the abundance of Wittenberg polluted soil-2 bacteria, Synergistota, Bacteroidales, Colidextribacter, Eggerthellaceae, Oscillospira, Oscillibacter, UCG-009, Barnesiellaceae and Lachnospiraceae_UCG-010 in cecal contents (P < 0.05). Dietary requirements for 25(OH)D3 for ducks (60 to 76 wk), were estimated to be 3377 IU/kg for egg production, 3434 IU/kg for egg mass, and 3256 IU/kg for FCR. In summary, dietary 25(OH)D3 supplementation improved productive performance and influenced liver and plasma lipid homeostasis in aged laying ducks, which may be associated with the reduction of bacteria involved in carbohydrate metabolism in the cecum. Supplementing the basal diet with 3250 to 3450 IU/kg 25(OH)D3 is recommended for aged laying ducks (60 to 76 wk).

Enhanced anti-inflammatory effects and metabolic profiles of cyanidin-3-glucoside via nanoliposomal encapsulation in Caco-2 and RAW 264.7 co-culture system

Cyanidin-3-glucoside (C3G) has been found to prevent/treat intestinal disease and maintain gut homeostasis. Numerous studies have proved that nanoliposomes can improve the absorption and utilization of food nutrients. However, the impacts of C3G nanoliposomes (C3G-NL) are still unkown. This study investigated the effects of cyanidin-3-glucoside nanoliposomes (C3G-NL) on intestinal inflammation and permeability using a Caco-2/RAW264.7 co-culture model. ELISA and qPCR results showed that C3G-NL reduced pro-inflammatory markers, including TNF-α, IL-6, IL-8, cyclooxygenase-2, and inducible nitric oxide synthase, while inhibiting the NF-κB/MAPK pathway. C3G-NL also improved intestinal barrier integrity by increasing transepithelial electrical resistance and upregulating tight junction proteins (zonula occludens-1, occludin, claudin-1). Additionally, C3G-NL enhanced C3G metabolism, leading to the formation of intermediary metabolites like chalcone and dihydroflavonols, which contributed to the synthesis of other anthocyanins (delphinidin, peonidin, petunidin, malvidin, and pelargonidin). Overall, C3G-NL helps mitigate inflammation and restore tight junction integrity via metabolic regulation.

Promoting Polarization and Differentiation of Primary Human Salivary Gland Stem/Progenitor Cells in Protease-Degradable Hydrogels via ROCK Inhibition.

Towards the goal of in vitro engineering of functional salivary gland tissues, we cultured primary human salivary stem/progenitor cells (hS/PCs) in hyaluronic acid-based matrices with varying percentages of proteolytically degradable crosslinks in the presence of Rho kinase (ROCK) inhibitor. Single cells encapsulated in the hydrogel grew into organized multicellular structures by day 15, and over 60% of the structures developed in the non-degradable and 50% degradable hydrogels contained a central lumen. Importantly, ROCK inhibition led to the establishment of multicellular structures that were correctly polarized, as evidenced by apical localization of a Golgi marker GM130, apical/lateral localization of tight junction protein zonula occludens-1 (ZO-1), and basal localization of integrin β1 and basement membrane proteins laminin α1 and collagen IV. Cultures maintained in 50% degradable gels with ROCK inhibition exhibited an increased expression of acinar markers AQP5 and SLC12A2 (at the transcript level) and AQP5 and NKCC1 (at the protein level) as compared to those without ROCK inhibition. Upon stimulation with isoproterenol, α-amylase secretion into the lumen was observed. Particle-tracking microrheology was employed to analyze the stiffness of cells using mitochondria as the passive tracer particles. Our results indicated that cells grown in 100% degradable gels were stiffer than those maintained in non-degradable gels, and cells cultured with the ROCK inhibitor were softer than those maintained without the inhibitor. We conclude that reducing cellular contractility via ROCK inhibition while retaining some degree of matrix confinement promotes the establishment of multicellular structures containing pro-acinar cells with correct apicobasal polarization.

Phenolics-Rich Extract from Agarwood Leaf-Tea Alleviate Dextran Sulfate Sodium (DSS)-Induced Ulcerative Colitis Via Modulating Intestinal Barrier Function, Liver Inflammation, and Gut Microbiota.

At present, the incidence rate of ulcerative colitis (UC) continues to increase, causing a global burden. In addition, therapeutic drugs have great side effects. According to modern pharmacology, agarwood leaves have anti-inflammatory, antibacterial, hypoglycemic, and lipid-lowering effects. Therefore, this experiment on DSS induced colitis treatment of polyphenolic substances in agarwood leaves is feasible and in line with the current hot topic of using natural substances instead of drugs for treatment. ALP supplementation promotes the expression of tight junction proteins occludin and Zonula occludens protein 1 (ZO-1) on colonic tissues, repairs the intestinal barrier, and relieves further colonic tissue damage. Besides, ALP effectively inhibits the activation of nuclear factor kappa-B (NF-кB) signaling pathway and reduces the release of proinflammatory cytokines. Moreover, ALP reverses the alteration of gut microbiota in the colitic mice by increasing the abundances of Parabacteroides, Chlamydia, and Lachnospiraceae, and decreasing the abundances of Bacteroides and Phocaeicola. Furthermore, the correlation analysis suggested that ALP can attenuate DSS-induced UC, which is probably related to the alterations in the gut microbiota. ALP can ameliorate DSS-induced UC by modulating gut microbiota, intestinal barrier function, and inflammatory responses.

Sustained immune activation and impaired epithelial barrier integrity in the ectocervix of women with chronic HIV infection.

Chronic systemic immune activation significantly influences human immunodeficiency virus (HIV) disease progression. Despite evidence of a pro-inflammatory environment in the genital tract of HIV-infected women, comprehensive investigations into cervical tissue from this region remain limited. Similarly, the consequences of chronic HIV infection on the integrity of the female genital epithelium are poorly understood, despite its importance in HIV transmission and replication. Ectocervical biopsies were obtained from HIV-seropositive (n = 14) and HIV-seronegative (n = 47) female Kenyan sex workers. RNA sequencing and bioimage analysis of epithelial junction proteins (E-cadherin, desmoglein-1, claudin-1, and zonula occludens-1) were conducted, along with CD4 staining. RNA sequencing revealed upregulation of immunoregulatory genes in HIV-seropositive women, primarily associated with heightened T cell activity and interferon signaling, which further correlated with plasma viral load. Transcription factor analysis confirmed the upregulation of pro-inflammatory transcription factors, such as RELA, NFKB1, and IKZF3, which facilitates HIV persistence in T cells. Conversely, genes and pathways associated with epithelial barrier function and structure were downregulated in the context of HIV. Digital bioimage analysis corroborated these findings, revealing significant disruption of various epithelial junction proteins in ectocervical tissues of the HIV-seropositive women. Thus, chronic HIV infection associated with ectocervical inflammation, characterized by induced T cell responses and interferon signaling, coupled with epithelial disruption. These alterations may influence HIV transmission and heighten susceptibility to other sexually transmitted infections. These findings prompt exploration of therapeutic interventions to address HIV-related complications and mitigate the risk of sexually transmitted infection transmission.

Study repair function of mucin-2 on the tight junction protein of uterine epithelial cells under bacterial endotoxins

To analysis repair function of mucin-2(MUC2) and glycoprotein particles on the tight junction protein of uterus under bacterial endotoxins. In this experiment, we showed that the thicker mucus layer of the uterus is used to prevent the translocation of endotoxin at 21d postdelivery. When endotoxin acts on the uterus to thin its mucous layer, the cells in the lamina propria of the uterus secrete a large number of glycoprotein particles at 27d postdelivery. Due to a significantly decrease in the expression of glycosyltransferase, the glycoprotein particles are incompletely glycosylation MUC2, which can interact with the cell membrane and are released in large quantities in the form of exocytosis. These glycoprotein particles can significantly repair tight junction proteins in the inter-cellular space and significantly increase the expression of Claudin-1, JAM (Junction adhesion molecule-A), E-cadherin, ZO-1(Zonula occludens-1) and desmosome proteins after endotoxin treatment. The results of the present study show that endotoxins can thin the uterine mucus layer and accelerate the release of incompletely glycosylated MUC2 from lamina propria cells. In inter-cellular spaces, MUC2 can increase its expression levels and distribution area to repair the tight junction structure of cells with larger gaps. Further strengthening of the barrier prevents endotoxin translocation by repairing the tight junction structure of uterine epithelial cells.

Oleanolic acid induces hepatic injury by disrupting hepatocyte tight junction and dysregulation of farnesoid X receptor-mediated bile acid efflux transporters.

Oleanolic acid (OA) is a naturally occurring pentacyclic triterpene compound that has been reported to cause cholestatic liver injury. However, the regulation and pathogenic role of bile acids in OA-induced development of cholestatic liver injury remains largely unclear. Farnesoid X receptor (FXR) is a metabolic nuclear receptor that plays an important role in bile acid homeostasis in the liver by regulating efflux transporters bile salt export pump (BSEP) and multidrug resistance-associated protein 2 (MRP2). The aim of this study was to investigate the effect of OA on hepatocyte tight junction function and determine the role of FXR, BSEP, and MRP2 in the mechanism of impairment of transport of bile acids induced by OA. Both in vivo and in vitro models were used to characterize the OA-induced liver injury. The liquid chromatography-tandem mass spectrometry (LC-MS) was employed to characterize the efflux function of the transporters, and the results showed that OA caused a blockage of bile acids efflux. OA treatment resulted in decreased expression levels of the tight junction proteins zonula occludens-1 and occludin. Immunofluorescence results showed that OA treatment significantly reduced the number of bile ducts and the immunofluorescence intensity. Pretreatment with agonists of FXR and MRP2, respectively, in animal experiments attenuated OA-induced liver injury, while pretreatment with inhibitors of BSEP and MRP2 further aggravated OA-induced liver injury. These results suggest that OA inhibits FXR-mediated BSEP and MRP2, leading to impaired bile acid efflux and disruption of tight junctions between liver cells, resulting in liver damage.

Lipid-lowering and antioxidant properties of probiotic Bifidobacterium animalis MSMC83 in rats on a high-fat diet.

Hyperlipidaemia, the abnormally high concentration of lipids such as cholesterol in the body, has a series of deleterious effects on health that are least in part are due to increased inflammation and oxidative stress. Probiotics are living microorganisms that possess the efficacy to improve health. Among the many effects that have been ascribed to probiotics is the potential to lower the body lipid content. Here, we used a rat model of induced hyperlipidaemia to assess the lipid-lowering and antioxidant properties of the probiotic strain Bifidobacterium animalis MSMC83 as well as its impact on intestinal barrier immunity and the intestinal microbiota. Oral probiotic intake led to a reduction of body weight, fasting blood glucose, and lipid levels, and increased expression of cholesterol-7α-hydroxylase and antioxidant enzymes. Additionally, B. animalis MSMC83 decreased the levels of liver enzymes and pro-inflammatory cytokines, leading to reduced hepatic steatosis. Furthermore, it re-established intestinal barrier integrity as shown by restoration of the tight junction protein zonula occludens-1 amount and reduced pathogen-induced inflammation in the intestinal epithelium as shown by readjusted expression of toll-like receptors (TLRs). Moreover B. animalis MSMC83 contributed to the maintenance of a balanced, diverse microbiome. Thus, our results indicate that B. animalis MSMC83 alleviates risk factors associated with hyperlipidaemia, suggesting its use as a probiotic to counter the effects associated with unhealthy diets.

Ruhao Dashi granules exert therapeutic effects on H1N1 influenza virus infection by altering intestinal microflora composition.

Antiviral medications for influenza could be ineffective due to the emergence of resistant influenza virus strains. Ruhao Dashi (RHDS) granules possess anti-inflammatory and antibacterial effects. The present study aimed to determine the efficacy of RHDS granules in treating influenza-infected mice and the mechanism underlying this treatment as well as its effect on the intestinal flora composition of the infected mice. The HPLC-UV method was used to identify the active components of RHDS granules. ICR mice were infected with influenza A virus (IAV) H1N1 subtype through a nasal drip. After the influenza mice model was successfully established, the pathological changes in the lungs were observed for 5 days after gavage treatment with 0.9% sterile saline and low, medium, and high doses (0.07, 0.14, and 0.28 g/mL, respectively) of RHDS granules. The serum levels of the cytokines IL-6 and TNF-α and sIgA were detected by ELISA. Real-time fluorescence quantitative PCR and western blotting assay were performed to determine the expression levels of the tight junction (TJ) proteins claudin-1, occludin, and zonula occludens-1 (ZO-1) in colon tissues. Furthermore, 16S rRNA gene sequencing of feces samples was conducted to assess the effect of RHDS granules on the gut microbiota. RHDS granules exerted a protective effect on the lung tissues of IAV-infected mice; moreover, the granules reduced the synthesis of proinflammatory cytokines and increased the relative expression levels of claudin-1, occludin, and ZO-1 in colon tissues. Furthermore, RHDS granule treatment increased the relative abundance of Lactobacillus, Akkermansia, and Faecalibaculum and decreased the relative abundance of Muribaculaceae; thus, RHDS granules could stabilize the intestinal microbiota to some extent. RHDS granules exert a therapeutic effect on IAV-infected mice probably by modifying the structural composition of their intestinal microbiota.

Bowel Inflammation and Nutrient Supplementation: Effects of a Fixed Combination of Probiotics, Vitamins, and Herbal Extracts in an In Vitro Model of Intestinal Epithelial Barrier Dysfunction.

The gut microbiota is a very important factor in the state of health of an individual, its alteration implies a situation of "dysbiosis," which can be connected to functional gastrointestinal disorders and pathological conditions, such as Inflammatory Bowel Disease (IBD), Irritable Bowel Syndrome (IBS), Ulcerative Colitis (UC) and Crohn's Disease (CD), and Colorectal Cancer (CRC). In this work, we studied the effect of a food supplement called ENTERO-AD containing a mix of probiotics (Lactobacillus acidophilus LA1, L. reuteri LR92, Bifidobacterium breve Bbr8), Matricaria Chamomilla, and B group vitamins (B1, B2, B6) on intestinal inflammation. The in vitro model used for the study is the Caco-2 cell, a culture derived from human intestinal adenocarcinoma; the inflammatory condition was achieved with treatment with Lipopolysaccharide (LPS) and the association between Tumor necrosis factor α/Interferon γ (TNF-α/IFN-γ) [1,2]. The effect of ENTERO-AD was evaluated by cell viability, measures of Transepithelial Electrical Resistance (TEER), paracellular permeability, and immunofluorescence. Results of the study have shown that ENTERO-AD has a favorable effect on Caco-2 cells in inflammatory conditions. It improves the integrity of Occludin and Zonula Occludens-1 (ZO-1) proteins, leading to an improvement in terms of TEER values and a reduction of paracellular permeability. This evidence underlines the protective effect of ENTERO-AD and its components in intestinal inflammation.

Effect of Probiotics on Improving Intestinal Mucosal Permeability and Inflammation after Surgery.

We explored the mechanisms underlying the improvement of postoperative ileus (POI) following probiotic pretreatment. We assessed intestinal permeability, inflammation, tight junction (TJ) protein expression in the gut epithelium, and plasma interleukin (IL)-17 levels in a guinea pig model of POI. Guinea pigs were divided into control, POI, and probiotic groups. The POI and probiotic groups underwent surgery, but the probiotic group received probiotics before the procedure. The ileum and proximal colon were harvested. Intestinal permeability was measured via horseradish peroxidase permeability. Inflammation was evaluated via leukocyte count in the intestinal wall muscle layer, and calprotectin expression in each intestinal wall layer was analyzed immunohistochemically. TJ proteins were analyzed using immunohistochemical staining, and plasma IL-17 levels were measured using an enzyme-linked immunosorbent assay. The POI group exhibited increased intestinal permeability and inflammation, whereas probiotic pretreatment reduced the extent of these POI-induced changes. Probiotics restored the expression of TJ proteins occludin and zonula occludens-1 in the proximal colon, which were increased in the POI group. Calprotectin expression significantly increased in the muscle layer of the POI group and was downregulated in the probiotic group; however, no distinct differences were observed between the mucosal and submucosal layers. Plasma IL-17 levels did not significantly differ among the groups. Probiotic pretreatment may relieve POI by reducing intestinal permeability and inflammation and TJ protein expression in the gut epithelium. These findings suggest a potential therapeutic approach for POI management.

Disulfiram attenuates cell and tissue damage and blood‒brain barrier dysfunction after intracranial haemorrhage by inhibiting the classical pyroptosis pathway

No single treatment significantly reduces the mortality rate and improves neurological outcomes after intracerebral haemorrhage (ICH). New evidence suggests that pyroptosis-specific proteins are highly expressed in the perihaematomal tissues of patients with ICH and that the disulfiram (DSF) inhibits pyroptosis. An ICH model was established in C57BL/6 mice by intracranial injection of collagenase, after which DSF was used to treat the mice. Cell model of ICH was constructed, and DSF was used to treat the cells. HE, TUNEL, Nissl, FJC and IF staining were performed to evaluate the morphology of brain tissues; Western blotting and ELISA were performed to measure the protein expression of NOD-like receptor protein 3 (NLRP3)/Caspase-1/gasdermin D (GSDMD) classical pyroptosis pathway and Toll-likereceptor4 (TLR4)/nuclear factor-kappaB (NF-κB) inflammatory signaling pathway and blood‒brain barrier-associated factoes, and the wet/dry weight method was used to determine the brain water content. The expression of proteins related to the NLRP3/Caspase-1/GSDMD pathway and the TLR4/NF-κB pathway was upregulated in tissues surrounding the haematoma compared with that in control tissues; Moreover, the expression of the blood–brain barrier structural proteins occludin and zonula occludens-1 (ZO-1) was downregulated, and the expression of Aquaporin Protein-4 (AQP4) and matrix metalloprotein 9 (MMP-9) was upregulated. DSF significantly inhibited these changes, reduced the haematoma volume, decreased the brain water content, reduced neuronal death and degeneration and improved neurological function after ICH. ICH activated the classical pyroptosis pathway and TLR4/NF-κB inflammatory pathway, disruped the expression of blood–brain barrier structural proteins, and exacerbated brain injury and neurological dysfunction. DSF inhibited these changes and exerted the therapeutic effects on pathological changes and dysfunction caused by ICH.

The protective effects of apelin-13 in HIV-1 tat- induced macrophage infiltration and BBB impairment

ABSTRACT Impairment of the blood – brain barrier (BBB) and subsequent inflammatory responses contribute to the development of human immunodeficiency virus (HIV)-1-associated neurocognitive disorders (HAND). Apelin-13, the most abundant member of the apelin family, acts as the ligand of the angiotensin receptor-like 1 (APJ). However, its pharmacological function in HAND and its underlying mechanism are unknown. In the current study, we report that the presence of HIV-1 Tat reduced the levels of Apelin-13 and APJ in the cortex tissue of mice. Importantly, Apelin-13 preserved BBB integrity against HIV-1 Tat in mice by increasing the expression of the tight junction protein zonula occludens-1 (ZO-1) and occludin. Interestingly, increased macrophage infiltration, indicated by elevated CD68-positive staining was observed in the cortex after stimulation with HIV-1, which was mitigated by the administration of Apelin-13. Correspondingly, Apelin-13 reduced the expression of monocyte chemoattractant protein-1; (MCP-1). An in vitro two-chamber and two-cell trans-well assay demonstrated that HIV-1 Tat challenge significantly promoted macrophage migration, which was notably attenuated by the introduction of Apelin-13. Accordingly, treatment with Apelin-13 restored the HIV-1 Tat-induced reduction of occludin and ZO-1, while preventing the upregulation of MCP-1 in human brain microvascular endothelial cells (HBMVECs). Our results suggest that Apelin-13 may reduce macrophage infiltration into brain tissues and mitigate BBB dysfunction in patients with HAND.

Xylan acetate ester ameliorates ulcerative colitis through intestinal barrier repair and inflammation inhibition via regulation of macrophage M1 polarization

Ulcerative colitis (UC) is a chronic inflammatory disease resulting from abnormal immune response to gut microflora translocating through damaged intestinal barrier. Xylan acetate ester (XylA) can increase colon short-chain fatty acids (SCFAs) levels and alleviate kidney disease by inhibiting inflammation through the G protein-coupled receptor pathway. Here, we synthesized and purified XylA, and then the effects and mechanisms of XylA on dextran sodium sulfate-induced UC in mice were investigated. The results showed that in mice, similar to the positive drug 5-aminosalicylic acid, oral administration of XylA significantly alleviated all UC symptoms, including weight loss, diarrhea, and hematochezia. Further mechanism studies revealed that XylA could repair the damaged colon structure and intestinal barrier function by increasing the expression of tight junction protein zonula occludens 1 and occludin, thus reducing LPS penetration. Moreover, XylA could also restrain intestinal inflammation via inhibiting LPS-TLR4 pathway, downregulating M1 macrophage polarization, and reducing proinflammatory cytokines expression, and in vitro cell experiments showed that these effects may be mediated by XylA derived SCFAs, particularly acetates, propionates and butyrates. All these results suggested that XylA may be a potential improving agent for UC treatment, and natural polysaccharides may represent a novel avenue for drug development of UC.

Neuroprotective effects of ulinastatin on Escherichia coli meningitis rats through inhibiting PKCα phosphorylation and reducing zonula occludens-1 degradation

Ulinastatin, a broad-spectrum inflammatory inhibitor widely employed in the management of severe pancreatitis and sepsis, has not been extensively investigated for its therapeutic potential in bacterial meningitis. This study aims to assess the neuroprotective effects of ulinastatin on bacterial meningitis and elucidate its underlying mechanism. The rat model of bacterial meningitis was established by intracerebral injection of Escherichia coli. 3-week-old SD rats were randomly divided into 5 groups with 8 rats in each group, including control group, E.coli group, E.coli + UTI group (ulinastatin 50000IU/kg), E.coli + UTI + PMA group (ulinastatin 50000IU/kg + PMA 200 ug/kg), and E.coli + PMA group(PMA 200 ug/kg). Behavioral changes were assessed by Loeffler neurobehavioral score. Histomorphologic changes and apoptosis were assessed by hematoxylin and eosin staining, Nissl staining and TUNEL staining. Immunohistochemistry and immunofluorescence and western blotting were used to detect the expression levels of zonula occludens-1 (ZO-1) and phosphorylation protein kinase C (PKCα).It was found that ulinastatin treatment in Escherichia coli meningitis rats improved neurological function, alleviated meningeal inflammatory infiltration, reduced neuronal death, promoted the integrity of the blood–brain barrier structure. Moreover, phorbol myristate acetate (PMA, a protein kinase C activator), blocked the effective action of ulinastatin. These findings suggest that ulinastatin had neuroprotective effects on bacterial meningitis by inhibiting PKCα phosphorylation and reducing ZO-1 degradation, demonstrating that ulinastatin may be a promising strategy in the treatment of bacterial meningitis.

Dietary Zn proteinate with moderate chelation strength alleviates heat stress-induced intestinal barrier function damage by promoting expression of tight junction proteins via the A20/NF-κB p65/MMP-2 pathway in the jejunum of broilers

BackgroundThe aim of this study was to determine whether and how Zn proteinate with moderate chelation strength (Zn-Prot M) can alleviate heat stress (HS)-induced intestinal barrier function damage of broilers. A completely randomized design was used for comparatively testing the effects of Zn proteinate on HS and non-HS broilers. Under high temperature (HT), a 1 (Control, HT-CON) + 2 (Zn source) × 2 (added Zn level) factorial arrangement of treatments was used. The 2 added Zn sources were Zn-Prot M and Zn sulfate (ZnS), and the 2 added Zn levels were 30 and 60 mg/kg. Under normal temperature (NT), a CON group (NT-CON) and pair-fed group (NT-PF) were included.ResultsThe results showed that HS significantly reduced mRNA and protein expression levels of claudin-1, occludin, junctional adhesion molecule-A (JAMA), zonula occludens-1 (ZO-1) and zinc finger protein A20 (A20) in the jejunum, and HS also remarkably increased serum fluorescein isothiocyanate dextran (FITC-D), endotoxin and interleukin (IL)-1β contents, serum diamine oxidase (DAO) and matrix metalloproteinase (MMP)-2 activities, nuclear factor kappa-B (NF-κB) p65 mRNA expression level, and protein expression levels of NF-κB p65 and MMP-2 in the jejunum. However, dietary supplementation with Zn, especially organic Zn as Zn-Prot M at 60 mg/kg, significantly decreased serum FITC-D, endotoxin and IL-1β contents, serum DAO and MMP-2 activities, NF-κB p65 mRNA expression level, and protein expression levels of NF-κB p65 and MMP-2 in the jejunum of HS broilers, and notably promoted mRNA and protein expression levels of claudin-1, ZO-1 and A20.ConclusionsOur results suggest that dietary Zn, especially 60 mg Zn/kg as Zn-Prot M, can alleviate HS-induced intestinal barrier function damage by promoting the expression of TJ proteins possibly via induction of A20-mediated suppression of the NF-κB p65/MMP-2 pathway in the jejunum of HS broilers.