Tight junction proteins

Digital light processing of photo-crosslinkable gelatin to create biomimetic 3D constructs serving small intestinal tissue regeneration

Regeneration of small intestinal mucosal tissue could offer a promising strategy for Crohn's disease patients suffering from chronic inflammatory damage. Here, we aimed to develop hydrogels that mirror the villi and crypts of the small intestine and exhibit a physiological stiffness of G' ~ 1.52 kPa. For this purpose, we developed gelatin-methacryloyl-aminoethyl-methacrylate (gel-MA-AEMA)-, and gelatin-methacryloyl-norbornene (gel-MA-NB)-based biomaterial inks to fabricate 3D hydrogels ("villi only" versus "crypts and villi") with digital light processing (DLP) and co-cultured Caco-2/HT29-MTX cells. Gel-MA-AEMA was selected for its higher amount of methacrylates which was hypothesized to provide superior photo-crosslinking kinetics and hence superior DLP fabrication potential while gel-MA-NB was evaluated for its selective functionalization potential with thiolated bioactive compounds following DLP processing, resulting from its incorporated NB moieties which remain unreacted during the DLP process. Both gel-MA-AEMA-, and gel-MA-NB-based hydrogels exhibited a physiologically relevant stiffness, but only the gel-MA-AEMA-based biomaterial ink could be successfully utilized for printing hydrogels encompassing villi and crypts. Paracellular permeability of small sized marker molecules in combination with transepithelial electrical resistance measurements showed the formation of a functional barrier over time on all hydrogel constructs. Transmission electron microscopy and enterocyte differentiation marker genes' expression levels revealed the superior differentiation of Caco-2 on the 3D constructs compared to 2D hydrogel sheets. In summary, while both hydrogels enhanced functional barrier formation and enterocyte differentiation, gel-MA-AEMA proved more conducive to DLP compared to gel-MA-NB. Furthermore, our study underscored the benefits of cultivating intestinal cells on soft 3D constructs, enhancing cell barrier properties and differentiation, thus providing added value over traditional 2D supports.

Effects of glutamine supplementation on the growth performance, antioxidant capacity, immunity and intestinal morphology of cold-stressed prestarter broiler chicks

BACKGROUND

Cold stress has important effects on the growth and production of broiler chickens. Glutamine (Gln) is a conditionally essential amino acid that plays an important role in promoting intestinal development and enhancing immune function. The aim of this study was to investigate the effects of Gln supplementation on the growth performance and health of cold-stressed prestarter broiler chicks.

METHODS AND RESULTS

A total of 375 1-day-old male SZ901 broilers were randomly divided into five groups (CON, CS, GLN1, GLN2, GLN3). Birds in the CON and CS groups were provided with normal drinking water, while the GLN1, GLN2 and GLN3 groups were provided with water supplemented with 0.4%, 0.8% and 1.2% Gln, respectively. At d7, birds in groups CS, GLN1, GLN2, and GLN3 were stressed at 12 ± 1 ℃ for 12 h. The results showed that cold stress significantly decreased the growth performance, serum antioxidant capacity and antibody concentrations, small intestine villus structure, and increased the gene expression of intestinal inflammatory factors of broiler chicks compared with the CON group (P < 0.05). Compared with the CS group, Gln supplementation exhibited increased growth performance, serum antioxidant capacity and antibody concentrations, gene expression levels of intestinal tight junction protein, villus height and villus height to crypt depth ratio (V/C) of small intestine, and decreased mRNA expression level of intestinal inflammatory factors (P < 0.05).

CONCLUSIONS

Gln supplementation ameliorated the impact of cold stress to a large extent as it promoted the development of the intestine and immune system and enhanced the antioxidant enzyme system in cold-stressed prestarter chicks.

The effect of amylase, chromium propionate and their combination supplementation on growth performance, carcass traits, serum parameters, antioxidant capacity and intestinal health in yellow feathered broilers

To better understand the growth promotion mechanism of amylase and chromium propionate (Cr Prop) and assess their potential synergistic effects, a total of 640 one-day-old male yellow-feathered broilers were randomly allocated to four dietary treatments with eight replicates. The birds were fed either a basal diet or the basal diet supplemented with amylase, Cr Prop or a combination of both. The results showed that during the grower, finisher and overall phases, average daily feed intake, final body weight, and feed conversion ratio were significantly improved (P < 0.05) in the amylase and Cr Prop treatment groups. However, no significant differences (P > 0.05) were observed in carcass traits. Amylase supplementation alone significantly reduced breast muscle drip loss (P < 0.05). Amylase supplementation significantly increased (P < 0.05) the concentration of glutathione peroxidase in breast muscle and plasma, as well as catalase in breast muscle, while it decreased (P < 0.05) catalase in the liver and malondialdehyde in breast muscle. Supplementation with Cr Prop significantly elevated (P < 0.05) the concentration of glutathione peroxidase in the liver and plasma, as well as the concentration of total superoxide dismutase in the liver, while it reduced (P < 0.05). the concentration of malondialdehyde in breast muscle. Supplementation with either amylase or Cr Prop significantly increased (P < 0.05) the levels of blood high-density lipoprotein cholesterol, immunoglobulin A, immunoglobulin G, and total protein, while significantly reducing (P < 0.05) triglyceride levels. Amylase supplementation alone notably enhanced villus height in both the jejunum and ileum. Furthermore, amylase or Cr Prop significantly upregulated (P < 0.05) the mRNA expression of Occludin and Claudin-1 in the Jejunum. The expression of Zona Occluden-1 was elevated by Cr Prop. However, the expression of Mucin 2 and Zona Occluden-2 remained unaffected. While amylase or Cr Prop supplementation alone could improve the performance and several healthy parameters in yellow-feathered broilers, no synergistic effect was observed.

Multi-omics profiling of dairy cattle oxidative stress identifies hindgut-derived Phascolarctobacterium succinatutens exhibiting antioxidant activity

An imbalance between oxidative and antioxidant processes in the host can lead to excessive oxidation, a condition known as oxidative stress (OS). Although changes in the hindgut microbiota have been frequently linked to OS, the specific microbial and metabolic underpinnings of this association remain unclear. In this study, we enrolled 81 postpartum Holstein cows and stratified them into high oxidative stress (HOS, n = 9) and low oxidative stress (LOS, n = 9) groups based on the oxidative stress index (OSi). Using a multi-omics approach, we performed 16S rRNA gene sequencing to evaluate microbial diversity, conducted metagenomic analysis to identify functional bacteria, and utilized untargeted metabolomics to profile serum metabolites. Our analyses revealed elevated levels of kynurenine, formyl-5-hydroxykynurenamine, and 5-hydroxyindole-3-acetic acid in LOS dairy cows. Additionally, the LOS cows had a higher abundance of short-chain fatty acids (SCFAs)-producing bacteria, including Bacteroidetes bacterium, Paludibacter propionicigenes, and Phascolarctobacterium succinatutens (P. succinatutens), which were negatively correlated with OSi. To explore the potential role of these bacteria in mitigating OS, we administered P. succinatutens (108 cfu/day for 14 days) to C57BL/6 J mice (n = 10). Oral administration of P. succinatutens significantly increased serum total antioxidant capacity, decreased total oxidants, and reduced OSi in mice. Moreover, this treatment promoted activation of the Nrf2-Keap1 antioxidant pathway, significantly enhancing the enzymatic activities of GSH-Px and SOD, as well as the concentrations of acetate and propionate in the colon. In conclusion, our findings suggest that systemic tryptophan metabolism and disordered SCFAs production are concurrent factors influenced by hindgut microbiota and associated with OS development. Modulating the hindgut microbiota, particularly by introducing specific SCFAs-producing bacteria, could be a promising strategy for combating OS.

Claudin 1 dysregulation disrupts coronary microvascular integrity and impairs cardiac function

BACKGROUND AND AIMS

Claudin 1 (Cldn1) is a tight junction protein primarily known for its role in epithelial and endothelial barrier function. However, the role of Cldn1 in coronary microvascular barrier remain unclear. The aim of this study is to investigate the biological effects of Cldn1 dysregulation on coronary vascular permeability, inflammation, fibrosis, and left ventricular function.

METHODS

Cldn1 was silenced in human cardiac microvascular endothelial cells (HMVECs) and C57Bl/6 mice using oligonucleotide-based next generation siRNA duplex. Additionally, global transgenic mice with endothelial cell-specific overexpression of Cldn1 were created under the regulation of the CD144 (VE-cadherin) promoter. Permeability was assessed using FITC-dextran assay in vitro and Evans blue dye leakage (Mile's assay) in vivo. Cardiac morphology and function were measured by cardiac MRI, and myocardial pathology was analyzed by immunohistochemistry and Transmission Electron Microscopy (TEM). PCR and Western blotting confirmed Cldn1 expression changes.

RESULTS

Cldn1 knockdown reduced protein levels by 46% (p = 0.004) and significantly increased endothelial permeability in HMVEC (p = 0.0007). In mice, Cldn1 knockdown significantly increased Evans blue dye leakage (p = 0.025), macrophage infiltration (p = 0.018), and interstitial collagen (p = 0.048). TEM confirmed endothelial damage particularly affecting the basement membrane structure. Cardiac MRI showed reduced stroke volume (p = 0.004) and ejection fraction (p = 0.043). Cldn1 overexpression reduced vascular permeability (p = 0.002) without altering cardiac function under basal condition.

CONCLUSION

Cldn1 plays an important role in maintaining coronary microvascular barrier integrity. Its loss leads to increased permeability, inflammation, fibrosis, and impaired cardiac function, while overexpression enhances barrier function without affecting cardiac performance under baseline conditions.

Total darkness activated intestinal clock system and improved intestinal barrier function in growing rabbits

The aim of study was to investigate the effects of dark environment on production performance, intestinal barrier function and clock-related gene expression in rabbits. Forty weaned rabbits with similar body weight (35-day-old) were randomly divided into 2 treatments (20 replicates per treatment, 1 rabbit per replicate: normal light group (12 L and 12 D) or total dark group (24 D). The experimental period lasted for 10 days, with an adaptation period of 3 days and a subsequent formal experimental period of 7 days. The results showed that feed-to-weight ratio of rabbits in total dark group was significantly decreased compared with normal light group. Dark treatment significantly increased gene expression of claudin-1, mucin1 in duodenum, occludin-1, claudin-1, zona occludens 1 (ZO1), junctional adhesion molecule 2 (JAM2) and interleukin 10 (IL10) in jejunum, claudin-1, mucin1, ZO1 and IL10 in ileum and clock, melatonin 1 A, melatonin 1B, and period1 in cecum compared with normal light group. Total dark treatment increased alpha diversity via increasing chao1 index, observed species index and faith_pd index of cecal flora. Total dark treatment significantly reduced percentage of Deferobacterium at phylum level in cecum, but significantly increased percentage of Rumenococci at genus level. There is an insignificant increasing tendency of acetic acid and propionic acid content of soft feces in total dark group. In conclusion, total dark treatment improves feed conversion efficiency in rabbits and activates cecum clock system, which increased diversity of bacterial flora and production of short-chain fatty acids, then increases intestinal barrier function.

Grape pomace extract attenuates high fat diet-induced endotoxemia and liver steatosis in mice

Obesity is a prominent global health concern associated with chronic inflammation and metabolic disorders, such as insulin resistance, type 2 diabetes, and non-alcoholic fatty liver disease (NAFLD). Excessive consumption of saturated fats exacerbates these conditions by increasing intestinal barrier permeability and circulating endotoxins. This study aims to investigate, in a murine model of high-fat diet (HFD)-induced obesity, the potential beneficial effects of a grape pomace extract (GPE), rich in phenolic compounds, at mitigating endotoxemia, and liver steatosis. Underlying mechanisms were characterized in an in vitro model of intestinal inflammation and permeabilization, as induced by tumor necrosis factor alpha (TNFα) in Caco-2 cell monolayers. Consumption of a HFD (60% calories from fat) for 13 weeks induced obesity, insulin resistance, and liver damage, evidenced by higher levels of plasma alanine aminotransferase (ALT), hepatic triglycerides content, and steatosis. In addition, HFD caused metabolic endotoxemia, hepatic toll-like receptor 4 (TLR4) upregulation and inflammation. GPE supplementation significantly reduced body weight and subcutaneous and visceral adipose tissue weight, and attenuated metabolic dysregulation. Furthermore, GPE decreased circulating LPS levels and mitigated HFD-mediated hepatic TLR4 upregulation, nuclear factor kappa B (NF-κB) activation, and downstream expression of proteins involved in oxidative stress and inflammation (NOX4, TNFα, and F4/80). In Caco-2 cells, GPE mitigated TNFα-induced monolayer permeabilization, decreased tight junction (TJ) protein levels, enhanced cellular oxidant production, activated redox-sensitive signaling, i.e., NF-κB and ERK1/2, and increased NOX1 and MLCK mRNA levels, the latter being a key regulator of monolayer permeability. The above findings suggest that GPE may protect against HFD-induced obesity and associated metabolic dysfunction (insulin resistance and NAFLD) by modulating intestinal barrier integrity and related endotoxemia.

Effects of enrofloxacin and povidone-iodine on immunity, the intestinal microbiome and transcriptome of juvenile grass carp (Ctenopharyngodon idella)

Gut microbiota stability is crucial for maintaining fish health. In aquaculture, antibiotics and disinfectants are frequently used to manipulate the host gut microbiota, but the combined effects on asymptomatic fish remain unclear. We investigated the effects of single and combined treatments with antibiotics and disinfectants on grass carp (Ctenopharyngodon idella) gut health, immune response, microbiome dynamics and transcriptome profile. In a 2-week trial, grass carp were exposed to enrofloxacin (10 mg/kg) in the basal diet or povidone-iodine (0.05 mg/L) in fresh water. A 14-day treatment led to significant oxidative stress, as indicated by reduced catalase and total superoxide dismutase activities. Digestive enzyme activities, including amylase and lipase, were also significantly suppressed. Gut microbiota diversity decreased, with notable shifts in dominant bacterial phyla, including reduced abundances of Firmicutes and Bacteroidetes and increased Proteobacteria and Fusobacteria. Transcriptomic analysis revealed downregulation of immune-related pathways, including those linked to IgA production, and suppression of key immune-related genes, such as major histocompatibility complex 2 (MHC2) and tumour necrosis factor alpha (TNF-α). Histopathological analysis showed damaged intestinal villi, increased goblet cell numbers and significant apoptosis in intestinal epithelial cells, as confirmed by terminal deoxynucleotidyl transferase (TdT) dUTP Nick-End Labeling (TUNEL) staining and upregulation of caspase-3, caspase-8 and caspase-9. These findings demonstrate that enrofloxacin and povidone-iodine disrupt gut microbiota balance, impair mucosal immunity and induce apoptosis in grass carp.

Post-stroke depression: exploring gut microbiota-mediated barrier dysfunction through immune regulation

Post-stroke depression (PSD) is one of the most common and devastating neuropsychiatric complications in stroke patients, affecting more than one-third of survivors of ischemic stroke (IS). Despite its high incidence, PSD is often overlooked or undertreated in clinical practice, and effective preventive measures and therapeutic interventions remain limited. Although the exact mechanisms of PSD are not fully understood, emerging evidence suggests that the gut microbiota plays a key role in regulating gut-brain communication. This has sparked great interest in the relationship between the microbiota-gut-brain axis (MGBA) and PSD, especially in the context of cerebral ischemia. In addition to the gut microbiota, another important factor is the gut barrier, which acts as a frontline sensor distinguishing between beneficial and harmful microbes, regulating inflammatory responses and immunomodulation. Based on this, this paper proposes a new approach, the microbiota-immune-barrier axis, which is not only closely related to the pathophysiology of IS but may also play a critical role in the occurrence and progression of PSD. This review aims to systematically analyze how the gut microbiota affects the integrity and function of the barrier after IS through inflammatory responses and immunomodulation, leading to the production or exacerbation of depressive symptoms in the context of cerebral ischemia. In addition, we will explore existing technologies that can assess the MGBA and potential therapeutic strategies for PSD, with the hope of providing new insights for future research and clinical interventions.

Response of YPM x Ross 708 male broilers to diets containing varying inclusions of phytase, calcium butyrate, and bacitracin methylene disalicylate during the grower and finisher periods-part 2: Intestinal health and physiology

This study evaluated the effects of calcium butyrate (CB) and bacitracin methylene disalicylate 50 (BMD) combined with different phytase concentrations on broiler intestinal health and physiology. Day-old YPM x Ross 708 male broilers (2,880) were distributed in 72 floor pens and assigned to 1 of 9 treatments (8 replicates/treatment). This experiment was a factorial arrangement including 2 phytase concentrations (500 or 1,500 FTU/kg) and 4 microbiota modulating feed additive levels (MMFA; (1) none, (2) only CB (0.5 g/kg of diet), (3) only BMD (55 mg/kg of diet), or (4) both CB and BMD). Additionally, a negative control without phytase and MMFA was included. Intestinal permeability was assessed on d 27. Jejunum wall and cecal content samples were collected on d 28 and 42 to assess jejunum villus height (VH), crypt depth, tight-junction and mucin gene expression, cecal microbiome diversity, and predicted bacterial metabolic pathways. Phytase and MMFA did not influence intestinal permeability (P > 0.05). Combining both CB and BMD with 1,500 FTU/kg of phytase compared to 500 FTU/kg lowered d 28 VH (P ≤ 0.05). Jejunal expression of CL-1, CL-4, CL-5, and ZO-2 on d 28 as well as CL-2 on d 42 changed between MMFA when combined with 1,500 FTU/kg of phytase but not 500 FTU/kg (P ≤ 0.05). Day 42 Pielou's evenness increased when 1,500 FTU/kg of phytase was combined with both CB and BMD compared to no MMFA (P ≤ 0.05). The cecal microbial beta diversity was not influenced by phytase, MMFA, or their interaction (P > 0.05). Overall, broiler intestinal health and physiology were influenced by CB and BMD depending on phytase concentration, demonstrating the complex interactions between these feed additives.

Lactobacillus lysates protect oral epithelial cells from pathogen-associated damage, increase secretion of pro-inflammatory cytokines and enhance barrier integrity

Periodontitis is a chronic gum disease characterised by inflammation and the loss of bone. We have explored the potential prophylactic effects of lysates from four Lactobacillus strains against the toxic effects of three periodontal pathogens (Porphyromonas gingivalis, Fusobacterium nucleatum, and Aggregatibacter actinomycetemcomitans). TR146 oral epithelial cells were pre-treated with Lactobacillus lysates (L. rhamnosus - GG, L. rhamnosus - SD11, L. reuteri and L. plantarum) and then challenged with pathogenic material (live cells, lysates, or supernatants). Cytokine analysis was performed on supernatants of cells treated with probiotic lysates from 1.5 h to 24 h. Effects of probiotic lysates on re-epithelialisation were determined using keratinocyte scratch assays, monitoring both migration and proliferation. Epithelial barrier function was observed after lysate addition by trans-epithelial electrical resistance (TEER) and by quantifying claudin-1 expression. Treatment of host cells with Lactobacillus lysates before pathogen exposure conferred significant protection against viability loss. Although extended pre-treatment did not generally increase protection, against live Aggregatibacter actinomycetemcomitans, significant increases in viability were seen after 24 h of pre-treatment for GG, SD11 and L. plantarum. Pro-inflammatory cytokines TNF-α, IP-10, IL-6, and IL-8 increased significantly with extended probiotic treatment, while IL-1β and IL-1α secretion significantly increased but remained constant over time. Secretion of the growth-promoting cytokine TGF-β increased after 3 h of treatment, however no increases in the regulatory cytokine IL-10 were recorded. Only exposure to SD11 significantly enhanced re-epithelialisation, TEER and claudin-1 expression while GG increased TEER but decreased claudin-1 expression. L. plantarum significantly inhibited re-epithelialisation but did not impact TEER or claudin-1 expression. All lysates significantly improved TEER in the presence of pathogenic material, demonstrating a protective effect on barrier function.

Dysbiosis and extraintestinal cancers

The gut microbiota plays a crucial role in safeguarding host health and driving the progression of intestinal diseases. Despite recent advances in the remarkable correlation between dysbiosis and extraintestinal cancers, the underlying mechanisms are yet to be fully elucidated. Pathogenic microbiota, along with their metabolites, can undermine the integrity of the gut barrier through inflammatory or metabolic pathways, leading to increased permeability and the translocation of pathogens. The dissemination of pathogens through the circulation may contribute to the establishment of an immune-suppressive environment that promotes carcinogenesis in extraintestinal organs either directly or indirectly. The oncogenic cascade always engages in the disruption of hormonal regulation and inflammatory responses, the induction of genomic instability and mutations, and the dysregulation of adult stem cell proliferation. This review aims to comprehensively summarize the existing evidence that points to the potential role of dysbiosis in the malignant transformation of extraintestinal organs such as the liver, breast, lung, and pancreas. Additionally, we delve into the limitations inherent in current methodologies, particularly the challenges associated with differentiating low loads gut-derived microbiome within tumors from potential sample contamination or symbiotic microorganisms. Although still controversial, an understanding of the contribution of translocated intestinal microbiota and their metabolites to the pathological continuum from chronic inflammation to tumors could offer a novel foundation for the development of targeted therapeutics.

IFN-β production induced by PRRSV is affected by GP3 quantity control and CLND4 interaction

Porcine reproductive and respiratory syndrome virus (PRRSV) is one of the most harmful pathogens in the swine industry. Our previous studies demonstrated that the small extracellular domain (ECL2) of CLDN4 effectively blocks PRRSV infection. In this study, we explored the in vivo administration of swine ECL2 (sECL2) and found that it blocked HP-PRRSV infection and alleviated histopathological changes in organs. Notably, sECL2 stimulated cytokine production in the lungs. We observed that CLDN4 upregulated the expression of IFN-β at low doses of GP3. While high doses of GP3 inhibited the activity of the IFN-β promotor, regardless of whether CLDN4 was present. GP3 also downregulated IFN-β by decreasing the phosphorylation of TBK1 and IRF3. These findings highlight functional differences in GP3 under quantity control, which account for the variations in IFN-β induction during the early and late stages of infection. Our results indicate that sECL2 is a promising candidate drug for developing treatments to control PRRS.

The effect size of rs521851 in the intron of MAGI2/S-SCAM on HADS-D scores correlates with EAT-26 scores for eating disorders risk

An association between the MAGI2 (S-SCAM) intron variant rs521851 and depression symptoms, as measured by the depression subscale of the Hospital Anxiety and Depression Scale (HADS-D), has been recently reported. The role of MAGI2 in depression has been linked to disruptions in the gut-brain axis. In this study, we investigated the association between rs521851 and HADS-D scores in an independent cohort of 380 individuals, consisting of 238 patients with an ICD-10 diagnosis of depression and 142 healthy controls. The original association was replicated in the patient cohort but not in the control group. Further analysis revealed that the effect size of rs521851 on HADS-D scores was moderated by Eating Attitudes Test 26 (EAT-26) scores. In participants with an EAT-26 score of ≥20, the effect size of rs521851 on HADS-D was more than 20 times greater compared to those with an EAT-26 score of <20. These findings successfully replicate the original association signal for MAGI2 and HADS-D, and highlight the role of MAGI2 in gut-brain interactions.

Effects of substituting soybean meal with fermented rapeseed meal mixture on the growth performance, slaughter performance, meat quality, blood biochemical indices and intestinal barrier function in Langshan Chickens

This study aimed to explore the effects of substituting soybean meal with a mixture of solid-state fermented rapeseed meal, apple pomace, and wheat bran on the growth performance, slaughter performance, meat quality, blood biochemical indices and intestinal barrier function of Langshan chickens. A total of 144 30-day-old Langshan chickens with similar body weights were randomly divided into three treatment groups, with six replicates per group and eight chickens per replicate: the control group (CON) was fed a corn-soybean meal basal diet, while the rapeseed meal mixture group (RSM) and the fermented rapeseed meal mixture group (FRSM) were fed diets substituting 5 % of soybean meal with rapeseed meal mixture and fermented rapeseed meal mixture, respectively. The trial lasted from 30 to 58 days of age. The results showed that compared to the CON group, the RSM group exhibited no significant changes in average daily feed intake (ADFI), average daily gain (ADG) and feed to gain ratio (F/G) (P > 0.05); the dressing percentage, half-eviscerated yield and eviscerated yield decreased (P < 0.05); the pH24h and yellowness of breast muscle increased (P < 0.05); the crypt depth of the jejunum decreased, and the villus height/crypt depth ratio increased (P < 0.05); the serum D-lactic acid content decreased (P < 0.05). Compared to the CON group, the FRSM group exhibited no significant changes in ADFI, ADG and F/G (P > 0.05); the eviscerated yield increased (P < 0.05); the serum glucose and uric acid levels decreased (P < 0.05); the crypt depth of the jejunum decreased, and the villus height/crypt depth ratio increased (P < 0.05); the serum D-lactic acid content decreased (P < 0.05). Furthermore, compared to the RSM group, the FRSM group exhibited no significant changes in ADFI, ADG and F/G (P > 0.05); the dressing percentage, half-eviscerated yield and eviscerated yield increased (P < 0.05); the pH24h of breast muscle decreased; the serum glucose and uric acid levels decreased (P < 0.05).In conclusion, RSM reduced the slaughter performance of Langshan chickens, while FRSM improved their slaughter performance. Both RSM and FRSM improved the jejunal morphology and intestinal permeability in Langshan chickens. In conclusion, fermentation improved the feed value of the rapeseed meal mixture; replacing part of the soybean meal diet with fermented rapeseed meal mixture helped improve the slaughter performance and intestinal barrier of Langshan chickens.

Poria cocos polysaccharide alleviates dextran sulphate sodium-induced ulcerative colitis in mice by modulating intestinal inflammatory responses and microbial dysbiosis

Poria cocos polysaccharide (PCP), one of the main active components of P. cocos, is extensively used worldwide and exhibits strong pharmacological effects. However, whether PCP can attenuate inflammatory bowel disease remains unclear. In this study, we assessed the effects of PCP supplementation on dextran sulphate sodium (DSS)-induced ulcerative colitis (UC) in mice. We found that PCP supplementation mitigated UC symptoms in DSS-treated mice, as evidenced by reductions in body weight loss, colon length shortening and disease activity index score. Importantly, PCP supplementation enhanced colonic barrier integrity by increasing tight junction protein abundance and exerted anti-inflammatory effects by suppressing nuclear factor-κB (NF-κB) activation in DSS-treated mice. Furthermore, PCP supplementation reversed DSS-induced dysbiosis in colonic microbiota by increasing the colonic abundance of beneficial bacteria (e.g. Akkermansiaceae) and decreasing the colonic abundance of harmful bacteria (e.g. Erysipelotrichaceae) in DSS-treated mice. Although PCP supplementation failed to ameliorate DSS-induced UC in antibiotic-treated mice, faecal microbiota transplantation from PCP-administered mice ameliorated DSS-induced UC in antibiotic-treated mice. In summary, PCP alleviates UC in mice by attenuating intestinal inflammation via the inhibition of NF-κB activation and modulating the intestinal microbiota.

Evaluation of the Effect of Probiotic Supplementation on Intestinal Barrier Integrity and Epithelial Damage in Colitis Disease: A Systematic Review

CONTEXT

Previous reviews have focused on the effects of probiotics on colitis, but there is a need to understand their impact on barrier integrity and tight junction protein improvement in colitis.

OBJECTIVE

This study aimed to systematically examine the effects of probiotic use on barrier integrity in colitis disease. This study was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines.

DATA SOURCES

A systematic search in PubMed, Web of Science, Scopus, and Cochrane databases identified 2537 articles.

DATA EXTRACTION

As a result of the search, 2537 articles were accessed. Study results were summarized descriptively through discussions by intervention conditions, study population, measurement methods, and key findings. The included studies were independently reviewed and all authors reached consensus on the quality and major findings from the included articles. Forty-six studies that met the inclusion criteria were analyzed within the scope of the systematic review.

RESULTS

Although the study primarily utilized probiotics from the Lactobacillaceae family (notably, L casei, L reuteri, L rhamnosus, L plantarum, and L pentosus) and the Bifidobacteriaceae family (notably, B breve, B animalis, and B dentium), other probiotics also demonstrated positive effects on tight junction proteins. These effects are attributed to the production of bioactive and metabolic compounds, as well as short-chain fatty acids, which combat pathogens and reduce anti-inflammatory agents. However, it was observed that the effects of these probiotics on tight junction proteins varied depending on the strain and dose.

CONCLUSION

The beneficial effects of probiotics on remission in inflammatory bowel disease are well documented. Studies show that probiotics generally improve intestinal barrier function, but factors such as dose, duration, and bacterial species combinations need further clarification. Additionally, comprehensive studies are needed to understand how improved barrier function affects absorption in individuals.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO registration no. CRD42023452774.

Metformin modulates the TXNIP-NLRP3-GSDMD pathway to improve diabetic bladder dysfunction

To validate the therapeutic efficacy of metformin on diabetic bladder dysfunction (DBD) and further elucidate whether the TXNIP-NLRP3-GSDMD axis serves as a target for metformin in ameliorating DBD. C57BL/6J mice were induced with diet-induced obesity by being fed a high-fat diet (HFD) for 16 weeks. After establishing the model, the mice were treated with metformin for 4 weeks, and their glucose metabolism-related parameters were assessed. Urine spot assays and urodynamic measurements were conducted to reflect the bladder function and urinary behavior in mice, while histological examination was performed to observe morphological changes. Western blot analysis was employed to measure the expression levels of pyroptotic factors such as TXNIP, NLRP3, GSDMD, and tight junction proteins. Metformin treatment significantly improved glucose tolerance and insulin sensitivity in mice. Moreover, it showed promise in decreasing urinary spot occurrence, reducing urination frequency, alleviating non-voiding contractions, and stabilizing peak urinary pressure. Following metformin therapy, mice displayed restored epithelial fold structure, increased thickness of the muscular layer, substantial decrease in muscle fiber content, notably reduced levels of TXNIP and GSDMD proteins in the metformin-treated group compared to the DBD group, and restored expression of tight junction proteins Zo-1, Claudin-1, and Occludin. Metformin ameliorates urothelial cells damage in DBD mice by inhibiting TXNIP generation and reducing NLRP3 and GSDMD production.

A review of chitosan-based nanocarriers as drug delivery systems for brain diseases: Critical challenges, outlooks and promises

The administration of medicinal drugs orally or systemically limits the treatment of specific central nervous system (CNS) illnesses, such as certain types of brain cancers. These methods can lead to severe adverse reactions and inadequate transport of drugs to the brain, resulting in limited effectiveness. The CNS homeostasis is maintained by various barriers within the brain, such as the endothelial, epithelial, mesothelial, and glial barriers, which strictly control the movement of chemicals, solutes, and immune cells. Brain capillaries consist of endothelial cells (ECs) and perivascular pericytes, with pericytes playing a crucial role in maintaining the blood-brain barrier (BBB), influencing new blood vessel formation, and exhibiting secretory capabilities. This article summarizes the structural components and anatomical characteristics of the BBB. Intranasal administration, a non-invasive method, allows drugs to reach the brain by bypassing the BBB, while direct cerebral administration targets specific brain regions with high concentrations of therapeutic drugs. Technical and mechanical tools now exist to bypass the BBB, enabling the development of more potent and safer medications for neurological disorders. This review also covers clinical trials, formulations, challenges, and patents for a comprehensive perspective.

A flavonoid-rich extract of bergamot juice improves high-fat diet-induced intestinal permeability and associated hepatic damage in mice

Consumption of high-fat diets (HFDs) is a contributing factor to obesity, insulin resistance and non-alcoholic fatty liver disease (NAFLD). Several studies suggested the protective role of bioactives present in Citrus fruits against the above mentioned chronic metabolic conditions. In this study, we evaluated if a flavonoid-rich extract of Citrus bergamia (bergamot) juice (BJe) could inhibit HFD-induced intestinal permeability and endotoxemia and, through this mechanism, mitigate the associated hepatic damage in C57BL/6J mice. After 12 weeks of the treatment, HFD consumption caused high body weight (BW) gain, hyperinsulinemia, hyperglycemia, and dyslipidemia, which were mitigated by BJe (50 mg per kg BW) supplementation. Furthermore, supplementation with BJe prevented HFD-induced liver alterations, including increased plasma alanine aminotransferase (ALT) activity, increased hepatic lipid deposition, high NAS, and fibrosis. Mice fed a HFD for 12 weeks showed (i) a decrease in small intestine tight junction protein levels (ZO-1, occludin, and claudin-1), (ii) increased intestinal permeability, and (iii) endotoxemia. All these adverse events were mitigated by BJe supplementation. Linking the capacity of BJe to prevent HFD-associated endotoxemia, supplementation with this extract decreased the HFD-induced overexpression of hepatic TLR-4, downstream signaling pathways (MyD88, NF-κB and MAPK), and the associated inflammation, evidenced by increased MCP-1, TNF-α, IL-6, iNOS, and F4/80 levels. Overall, we suggest that BJe could mitigate the harmful consequences of western style diet consumption on liver physiology by protecting the gastrointestinal tract from permeabilization and associated metabolic endotoxemia.

Utilizing pigs as a model for studying intestinal barrier function

Intestinal permeability has been extensively studied, particularly in gastrointestinal diseases such as inflammatory bowel disease, food allergy, visceral disease, celiac disease, and Crohn’s disease. These studies have established that changes in intestinal permeability contribute to the pathogenesis of many gastrointestinal and systemic diseases. While numerous works in the 20th century focused on this topic, it remains relevant for several reasons. Despite the development of new research techniques, it is still unclear whether changes in intestinal permeability are the primary mechanism initiating the disease process or if they occur secondary to an ongoing chronic inflammatory process. Investigating the possibility of stabilizing the intestinal barrier, thereby reducing its permeability preemptively to prevent damage and after the damage has occurred, may offer new therapeutic approaches. Increased intestinal permeability is believed to lead to reduced nutrient absorption, resulting in decreased immunity and production of digestive enzymes.

A derivative of 3-(1,3-diarylallylidene)oxindoles inhibits dextran sulfate sodium-induced colitis in mice

BACKGROUND

IA-0130 is a derivative of 3-(1,3-diarylallylidene)oxindoles, which is a selective estrogen receptor modulator (SERM). A previous study demonstrated that SERM exhibits anti-inflammatory effects on colitis by promoting the anti-inflammatory phenotype of monocytes in murine colitis. However, the therapeutic effects of oxindole on colitis remain unknown. Therefore, we evaluated the efficacy of IA-0130 on dextran sulfate sodium (DSS)-induced mouse colitis.

METHODS

The DSS-induced colitis mouse model was established by administration of 2.5% DSS for 5 days. Mice were orally administered with IA-0130 (0.01 mg/kg or 0.1 mg/kg) or cyclosporin A (CsA; 30 mg/kg). Body weight, disease activity index score and colon length of mice were calculated and histological features of mouse colonic tissues were analyzed using hematoxylin and eosin staining. The expression of inflammatory cytokines and tight junction (TJ) proteins were analyzed using quantitative real-time PCR and enzyme-linked immunosorbent assay. The expression of interleukin-6 (IL-6) signaling molecules in colonic tissues were investigated using Western blotting and immunohistochemistry (IHC).

RESULTS

IA-0130 (0.1 mg/kg) and CsA (30 mg/kg) prevented colitis symptom, including weight loss, bleeding, colon shortening, and expression of pro-inflammatory cytokines in colon tissues. IA-0130 treatment regulated the mouse intestinal barrier permeability and inhibited abnormal TJ protein expression. IA-0130 down-regulated IL-6 expression and prevented the phosphorylation of signaling molecules in colonic tissues.

CONCLUSIONS

This study demonstrated that IA-0130 suppressed colitis progression by inhibiting the gp130 signaling pathway and expression of pro-inflammatory cytokines, and maintaining TJ integrity.

Intestinal barrier permeability: the influence of gut microbiota, nutrition, and exercise

The intestinal wall is a selectively permeable barrier between the content of the intestinal lumen and the internal environment of the body. Disturbances of intestinal wall permeability can potentially lead to unwanted activation of the enteric immune system due to excessive contact with gut microbiota and its components, and the development of endotoxemia, when the level of bacterial lipopolysaccharides increases in the blood, causing chronic low-intensity inflammation. In this review, the following aspects are covered: the structure of the intestinal wall barrier; the influence of the gut microbiota on the permeability of the intestinal wall via the regulation of functioning of tight junction proteins, synthesis/degradation of mucus and antioxidant effects; the molecular mechanisms of activation of the pro-inflammatory response caused by bacterial invasion through the TLR4-induced TIRAP/MyD88 and TRAM/TRIF signaling cascades; the influence of nutrition on intestinal permeability, and the influence of exercise with an emphasis on exercise-induced heat stress and hypoxia. Overall, this review provides some insight into how to prevent excessive intestinal barrier permeability and the associated inflammatory processes involved in many if not most pathologies. Some diets and physical exercise are supposed to be non-pharmacological approaches to maintain the integrity of intestinal barrier function and provide its efficient operation. However, at an early age, the increased intestinal permeability has a hormetic effect and contributes to the development of the immune system.

The Use of Polysaccharide AOP30 from the Rhizome of Alpinia officinarum Hance to Alleviate Lipopolysaccharide-Induced Intestinal Epithelial Barrier Dysfunction and Inflammation via the TLR4/NfκB Signaling Pathway in Caco-2 Cell Monolayers

Alpinia officinarum Hance is rich in carbohydrates and is flavored by natives. The polysaccharide fraction 30 is purified from the rhizome of A. officinarum Hance (AOP30) and shows excellent immunoregulatory ability when administered to regulate immunity. However, the effect of AOP30 on the intestinal epithelial barrier is not well understood. Therefore, the aim of this study is to investigate the protective effect of AOP30 on the intestinal epithelial barrier using a lipopolysaccharide (LPS)-induced intestinal epithelial barrier dysfunction model and further explore its underlying mechanisms. Cytotoxicity, transepithelial electrical resistance (TEER) values, and Fluorescein isothiocyanate (FITC)-dextran flux are measured. Simultaneously, the protein and mRNA levels of tight junction (TJ) proteins, including zonula occludens-1 (ZO-1), Occludin, and Claudin-1, are determined using Western blotting and reverse-transcription quantitative polymerase chain reaction methods, respectively. The results indicate that AOP30 restores the LPS-induced decrease in the TEER value and cell viability. Furthermore, it increases the mRNA and protein expression of ZO-1, Occludin, and Claudin-1. Notably, ZO-1 is the primary tight junction protein altered in response to LPS-induced intestinal epithelial dysfunction. Additionally, AOP30 downregulates the production of TNFα via the Toll-like receptor 4 (TLR4)/NF-κB signaling pathway. Collectively, the findings of this study indicate that AOP30 can be developed as a functional food ingredient or natural therapeutic agent for addressing intestinal epithelial barrier dysfunction. It sheds light on the role of AOP30 in improving intestinal epithelial function.

Prinsepia utilis Royle polysaccharides promote skin barrier repair through the Claudin family

BACKGROUND

Plant polysaccharides have various biological activities. However, few studies have been conducted on the skin barrier of Prinsepia utilis Royle polysaccharide extract (PURP).

MATERIALS AND METHODS

The proportions of polysaccharides, monosaccharides and proteins were determined by extracting polysaccharides from fruit meal using water. The healing rate was measured by cell scratch assays. SDS-damaged reconstructed human epidermal models, an acetone-ether-induced mouse model and an IL-4-induced cellular inflammation model were used to detect the effects of polysaccharides on the phenotype, HA, TEWL, and TEER, with further characterizations performed using QRT-PCR, Western blotting, immunofluorescence (IF) assays.

RESULTS

PURP contained 35.73% polysaccharides and 11.1% proteins. PURP promoted cell migration and increased skin thickness in a reconstructed human epidermis model. The TEWL significantly decreased, and the HA content significantly increased. PURP significantly increased the TEER and decreased the permeability of the SDS-damaged reconstructed human epidermis model. Claudin-3, Claudin-4, and Claudin-5 were significantly upregulated. IF and Western blot analysis revealed that the Claudin-4 level significantly increased after treatment with PURP. Claudin-1, Claudin-3, Claudin-4, and Claudin-5 gene expression and IF and immunohistochemical staining were significantly increased in mice treated with acetone-ether. PURP promoted the expression of Claudin-1, Claudin-3, Claudin-4, and Claudin-5 after treatment with 100 ng/mL IL-4. PURP also downregulated the expression of NO, IL6, TNFα and NFκB in Raw 264.7 cells and in a mouse model.

CONCLUSION

We hypothesize that PURP may repair the skin barrier by promoting the expression of the claudin family and can assist in skin therapy.

Gallic acid attenuates LPS-induced inflammation in Caco-2 cells by suppressing the activation of the NF-κB/MAPK signaling pathway

Inflammatory bowel disease (IBD) is a chronic inflammatory disease characterized by intestinal barrier dysfunction, inflammatory synergistic effects and excessive tissue injury. Gallic acid (GA) is renowned for its remarkable biological activity, encompassing anti-inflammatory and antioxidant properties. However, the underlying mechanisms by which GA protects against intestinal inflammation have not been fully elucidated. The aim of this study is to investigate the effect of GA on the inflammation of a lipopolysaccharide (LPS)-stimulated human colon carcinoma cell line (Caco-2) and on the intestinal barrier dysfunction, and explore the underlying molecular mechanism involved. Our findings demonstrate that 5 μg/mL GA restores the downregulation of the mRNA and protein levels of Claudin-1, Occludin, and ZO-1 and decreases the expressions of inflammatory factors such as IL-6, IL-1β and TNF-α induced by LPS. In addition, GA exhibits a protective effect by reducing the LPS-enhanced early and late apoptotic ratios, downregulating the mRNA levels of pro-apoptotic factors ( Bax, Bad, Caspase-3, Caspase-8, and Caspase-9), and upregulating the mRNA levels of anti-apoptotic factor Bcl-2 in Caco-2 cells. GA also reduces the levels of reactive oxygen species increased by LPS and restores the activity of antioxidant enzymes, namely, superoxide dismutase and catalase, as well as the level of glutathione. More importantly, GA exerts its anti-inflammatory effects by inhibiting the LPS-induced phosphorylation of key signaling molecules in the NF-κB/MAPK pathway, including p65, IκB-α, p38, JNK, and ERK, in Caco-2 cells. Overall, our findings show that GA increases the expressions of tight junction proteins, reduces cell apoptosis, relieves oxidative stress and suppresses the activation of the NF-κB/MAPK pathway to reduce LPS-induced intestinal inflammation in Caco-2 cells, indicating that GA has potential as a therapeutic agent for intestinal inflammation.

AG1®, a Novel Synbiotic, Maintains Gut Barrier Function following Inflammatory Challenge in a Caco-2/THP1-Blue™ Co-Culture Model

Nutritional interventions to reduce gastrointestinal (GI) permeability are of significant interest to physically active adults and those experiencing chronic health conditions. This in vitro study was designed to assess the impact of AG1, a novel synbiotic, on GI permeability following an inflammatory challenge. Interventions [AG1 (vitamins/minerals, pre-/probiotics, and phytonutrients) and control (control medium)] were fed separately into a human GI tract model (stomach, small intestine, and colon). In the colonic phase, the GI contents were combined with fecal inocula from three healthy human donors. GI permeability was evaluated with transepithelial electrical resistance (TEER) in a Caco-2 (apical)/THP1-Blue™ (basolateral) co-culture model. The apical side received sodium butyrate (positive control) or Caco-2 complete medium (negative control) during baseline testing. In the 24 h experiment, the apical side received colonic simulation isolates from the GI model, and the basolateral side was treated with Caco-2 complete medium, then 6 h treatment with lipopolysaccharide. TEER was assessed at 0 h and 24 h, and inflammatory markers were measured at 30 h in triplicate. Paired samples t-tests were used to evaluate endpoint mean difference (MD) for AG1 vs. control. TEER was higher for AG1 (mean ± SD: 99.89 ± 1.32%) vs. control (mean ± SD: 92.87 ± 1.22%) following activated THP1-induced damage [MD: 7.0% (p < 0.05)]. AG1 maintained TEER similar to the level of the negative control [-0.1% (p = 0.02)]. No differences in inflammatory markers were observed. These in vitro data suggest that acute supplementation with AG1 might stimulate protective effects on GI permeability. These changes may be driven by SCFA production due to the pre-/probiotic properties of AG1, but more research is needed.

Zeolite and Neurodegenerative Diseases

Neurodegenerative diseases (NDs), characterized by progressive degeneration and death of neurons, are strongly related to aging, and the number of people with NDs will continue to rise. Alzheimer's disease (AD) and Parkinson's disease (PD) are the most common NDs, and the current treatments offer no cure. A growing body of research shows that AD and especially PD are intricately related to intestinal health and the gut microbiome and that both diseases can spread retrogradely from the gut to the brain. Zeolites are a large family of minerals built by [SiO4]4- and [AlO4]5- tetrahedrons joined by shared oxygen atoms and forming a three-dimensional microporous structure holding water molecules and ions. The most widespread and used zeolite is clinoptilolite, and additionally, mechanically activated clinoptilolites offer further improved beneficial effects. The current review describes and discusses the numerous positive effects of clinoptilolite and its forms on gut health and the gut microbiome, as well as their detoxifying, antioxidative, immunostimulatory, and anti-inflammatory effects, relevant to the treatment of NDs and especially AD and PD. The direct effects of clinoptilolite and its activated forms on AD pathology in vitro and in vivo are also reviewed, as well as the use of zeolites as biosensors and delivery systems related to PD.

Progresses in the establishment, evaluation, and application of in vitro blood-brain barrier models

The blood-brain barrier (BBB) is a barrier between the circulatory system and the central nervous system (CNS), contributing to CNS protection and maintaining the brain homeostasis. Establishment of in vitro BBB models that are closer to the microenvironment of the human brain is helpful for evaluating the potential and efficiency of a drug penetrating BBB and thus the clinical application value of the drug. The in vitro BBB models not only provide great convenience for screening new drugs that can access to CNS but also help people to have a deeper study on the mechanism of substances entering and leaving the brain, which makes people have greater opportunities in the treatment of CNS diseases. Up to now, although much effort has been paid to the researches on the in vitro BBB models and many progresses have been achieved, no unified method has been described for establishing a BBB model and there is much work to do and many challenges to be faced with in the future. This review summarizes the research progresses in the establishment, evaluation, and application of in vitro BBB models.

An overview on the cellular mechanisms of anthocyanins in maintaining intestinal integrity and function

Structural and functional changes of the intestinal barrier, as a consequence of a number of (epi)genetic and environmental causes, have a main role in penetrations of pathogens and toxic agents, and lead to the development of inflammation-related pathological conditions, not only at the level of the GI tract but also in other extra-digestive tissues and organs. Anthocyanins (ACNs), a subclass of polyphenols belonging to the flavonoid group, are well known for their health-promoting properties and are widely distributed in the human diet. There is large evidence about the correlation between the human intake of ACN-rich products and a reduction of intestinal inflammation and dysfunction. Our review describes the more recent advances in the knowledge of cellular and molecular mechanisms through which ACNs can modulate the main mechanisms involved in intestinal dysfunction and inflammation, in particular the inhibition of the NF-κB, JNK, MAPK, STAT3, and TLR4 proinflammatory pathways, the upregulation of the Nrf2 transcription factor and the expression of tight junction proteins and mucins.

Effect of Porosity on the Colonization of Digital Light-Processed 3D Hydrogel Constructs toward the Development of a Functional Intestinal Model

With the rapid increase of the number of patients with gastrointestinal diseases in modern society, the need for the development of physiologically relevant in vitro intestinal models is key to improve the understanding of intestinal dysfunctions. This involves the development of a scaffold material exhibiting physiological stiffness and anatomical mimicry of the intestinal architecture. The current work focuses on evaluating the scaffold micromorphology of gelatin-methacryloyl-aminoethyl-methacrylate-based nonporous and porous intestinal 3D, intestine-like constructs, fabricated via digital light processing, on the cellular response. To this end, Caco-2 intestinal cells were utilized in combination with the constructs. Both porous and nonporous constructs promoted cell growth and differentiation toward enterocyte-like cells (VIL1, ALPI, SI, and OCLD expression showed via qPCR, ZO-1 via immunostaining). The porous constructs outperformed the nonporous ones regarding cell seeding efficiency and growth rate, confirmed by MTS assay, live/dead staining, and TEER measurements, due to the presence of surface roughness.

Targeting aryl hydrocarbon receptor to prevent cancer in barrier organs

The skin, lung, and gut are important barrier organs that control how the body reacts to environmental stressors such as ultraviolet (UV) radiation, air pollutants, dietary components, and microorganisms. The aryl hydrocarbon receptor (AhR) is a ligand-dependent transcription factor that plays an important role in maintaining homeostasis of barrier organs. AhR was initially discovered as a receptor for environmental chemical carcinogens such as polycyclic aromatic hydrocarbons (PAHs). Activation of AhR pathways by PAHs leads to increased DNA damage and mutations which ultimately lead to carcinogenesis. Ongoing evidence reveals an ever-expanding role of AhR. Recently, AhR has been linked to immune systems by the interaction with the development of natural killer (NK) cells, regulatory T (Treg) cells, and T helper 17 (Th17) cells, as well as the production of immunosuppressive cytokines. However, the role of AhR in carcinogenesis is not as straightforward as we initially thought. Although AhR activation has been shown to promote carcinogenesis in some studies, others suggest that it may act as a tumor suppressor. In this review, we aim to explore the role of AhR in the development of cancer that originates from barrier organs. We also examined the preclinical efficacy data of AhR agonists and antagonists on carcinogenesis to determine whether AhR modulation can be a viable option for cancer chemoprevention.

ZO-1 Serum Levels as a Potential Biomarker for Psychotic Disorder

OBJECTIVE

There are limited studies in the literature on the relationship between intestinal and blood-brain barrier permeability and the etiology of schizophrenia. We hypothesized that the difference in serum ZO-1 levels in patients with schizophrenia may affect the severity of the disease. The aim of this study was to investigate the role of changes in serum ZO-1 concentrations in the etiopathogenesis of patients with schizophrenia.

METHODS

A total of 46 patients, 34 with schizophrenia, 12 with a first psychotic attack, and 37 healthy controls, were included in the study. Symptom severity was determined by applying the Positive and Negative Syndrome Scale and the Clinical Global Impression-Severity Scale. Serum ZO-1 levels were measured from venous blood samples.

RESULTS

Serum ZO-1 levels were higher in patients with psychotic disorder compared to healthy controls. There was no statistically significant difference between the groups in the first psychotic attack group and the schizophrenia patients. There was a statistically significant positive correlation between serum ZO-1 levels and Positive and Negative Syndrome Scale positive symptom score.

CONCLUSIONS

These findings regarding ZO-1 levels suggest that dysregulation of the blood-brain barrier in psychotic disorder may play a role in the etiology of the disorder.

Dietary methanotroph bacteria meal alleviates soybean meal-induced enteritis by improving immune tolerance and intestinal flora profile of juvenile turbot (Scophthalmus maximus L.)

An 8-week growth trial was performed to investigate the protective effects of methanotroph bacteria meal (MBM) produced from methane against soybean meal-induced enteritis (SBMIE) in juvenile turbot (Scophthalmus maximus L.). Five isonitrogenous and isolipidic diets were formulated: fishmeal-based diet (FM, the control group); FM with approximate 50% of fishmeal substituted by 399.4 g/kg soybean meal (SBM); SBM supplemented with 63.6, 127.2 and 190.8 g/kg MBM (named MBM1, MBM2 and MBM3), each diet was randomly assigned to triplicate fibreglass tanks. Results showed that fish fed with SBM exhibited enteritis, identified by reduced relative weight of intestine (RWI), as well as expanded lamina propria width and up-regulated gene expression of pro-inflammatory cytokines (tnf-α, il-6 and il-8) in intestine. While the above symptoms were reversed when diet SBM supplemented with MBM at the levels of 63.6 and 127.2 g/kg, as well as characterized by up-regulated gene expression of anti-inflammatory cytokines (tgf-β and il-10) and tight junction protein (claudin3, claudin4 and claudin7) in intestine. Intestinal transcriptome analysis showed that the differentially expressed genes between groups FM and SBM predominantly enriched in the JAK-STAT signaling pathway, and the enrichment of differentially expressed genes between groups SBM and SBM supplemented with 63.6 g/kg MBM was in the inflammatory bowel disease (IBD) and JAK-STAT signaling pathway. To be specific, the expression of jak1, jak2b, stat1 and stat5a was significantly up-regulated when fish fed with SBM, suggested the activation of JAK-STAT signaling pathway, while the expression of these above genes was depressed by providing MBM to diet SBM, and the gene expression of toll-like receptors tlr2 and tlr5b showed a similar pattern. Moreover, intestinal flora analysis showed that community richness and abundance of beneficial bacteria (Cetobacterium and acillus_coagulans) were improved when fish fed with SBM supplemented with 63.6 g/kg MBM. Overall, methanotroph bacteria meal may alleviate SBMIE by regulating the expression of tight junction protein, toll-like receptors and JAK-STAT signaling pathway, as well as improving intestinal flora profile, which would be beneficial for enhancing the immune tolerance and utilization efficiency of turbot to dietary soybean meal.

Cryopreservation and Rapid Recovery of Differentiated Intestinal Epithelial Barrier Cells at Complex Transwell Interfaces Is Enabled by Chemically Induced Ice Nucleation

Cell-based models, such as organ-on-chips, can replace and inform in vivo (animal) studies for drug discovery, toxicology, and biomedical science, but most cannot be banked "ready to use" as they do not survive conventional cryopreservation with DMSO alone. Here, we demonstrate how macromolecular ice nucleators enable the successful cryopreservation of epithelial intestinal models supported upon the interface of transwells, allowing recovery of function in just 7 days post-thaw directly from the freezer, compared to 21 days from conventional suspension cryopreservation. Caco-2 cells and Caco-2/HT29-MTX cocultures are cryopreserved on transwell inserts, with chemically induced ice nucleation at warmer temperatures resulting in increased cell viability but crucially retaining the complex cellular adhesion on the transwell insert interfaces, which other cryoprotectants do not. Trans-epithelial electrical resistance measurements, confocal microscopy, histology, and whole-cell proteomics demonstrated the rapid recovery of differentiated cell function, including the formation of tight junctions. Lucifer yellow permeability assays confirmed that the barrier functions of the cells were intact. This work will help solve the long-standing problem of transwell tissue barrier model storage, facilitating access to advanced predictive cellular models. This is underpinned by precise control of the nucleation temperature, addressing a crucial biophysical mode of damage.

Effect of Cymbopogon martini (Roxb.) Will.Watson essential oil on antioxidant activity, immune and intestinal barrier-related function, and gut microbiota in pigeons infected by Candida albicans

Essential oils are potential alternatives to antibiotics for preventing Candida albicans (C. albicans) infection which is responsible for economic losses in the pigeon industry. Cymbopogon martini essential oil (EO) can inhibit pathogens, particularly fungal pathogens but its potential beneficial effects on C. albicans-infected pigeons remain unclear. Therefore, we investigated the impact of C. martini EO on antioxidant activity, immune response, intestinal barrier function, and intestinal microbiota in C. albicans-infected pigeons. The pigeons were divided into four groups as follows: (1) NC group: C. albicans uninfected/C. martini EO untreated group; (2) PC group: C. albicans infected/C. martini EO untreated group; (3) LPA group: C. albicans infected/1% C. martini EO treated group; and (4) HPA group: C. albicans infected/2% C. martini EO treated group. The pigeons were infected with C. albicans from day of age 35 to 41 and treated with C. martini EO from day of age 42 to 44, with samples collected on day of age 45 for analysis. The results demonstrated that C. martini EO prevented the reduction in the antioxidant enzymes SOD and GSH-Px causes by C. albicans challenge in pigeons. Furthermore, C. martini EO could decrease the relative expression of IL-1β, TGF-β, and IL-8 in the ileum, as well as IL-1β and IL-8 in the crop, while increasing the relative expression of Claudin-1 in the ileum and the crop and Occludin in the ileum in infected pigeons. Although the gut microbiota composition was not significantly affected by C. martini EO, 2% C. martini EO increased the abundance of Alistipes and Pedobacter. In conclusion, the application of 2% C. martini EO not only enhanced the level of antioxidant activity and the expression of genes related to intestinal barrier function but also inhibited inflammatory genes in C. albicans-infected pigeons and increased the abundance of gut bacteria that are resistant to C. albicans.

Human in vitro blood barrier models: architectures and applications

Blood barriers serve as key points of transport for essential molecules as well as lines of defense to protect against toxins. In vitro modeling of these barriers is common practice in the study of their physiology and related diseases. This review describes a common method of using an adaptable, low cost, semipermeable, suspended membrane to experimentally model three blood barriers in the human body: the blood-brain barrier (BBB), the gut-blood barrier (GBB), and the air-blood barrier (ABB). The GBB and ABB both protect from the outside environment, while the BBB protects the central nervous system from potential neurotoxic agents in the blood. These barriers share several commonalities, including the formation of tight junctions, polarized cellular monolayers, and circulatory system contact. Cell architectures used to mimic barrier anatomy as well as applications to study function, dysfunction, and response provide an overview of the versatility enabled by these cultural systems.

Cingulin family: Structure, function and clinical significance

Cingulin and its paralog paracingulin are vital components of the apical junctional complex in vertebrate epithelial and endothelial cells. They are both found in tight junctions (TJ), and paracingulin is also detectable in adherens junctions (AJ) as TJ cytoplasmic plaque proteins. Cingulin and paracingulin interact with other proteins to perform functions. They interact with cytoskeletal proteins, modulate the activity of small GTPases, such as RhoA and Rac1, and regulate gene expression. In addition, cingulin and paracingulin regulate barrier function and many pathological processes, including inflammation and tumorigenesis. In this review, we summarize the discovery and structure, expression and subcellular distribution, and molecular interactions of cingulin family proteins and discuss their role in development, physiology, and pathological processes.

Methionine sources and genotype affect embryonic intestinal development, antioxidants, tight junctions, and growth-related gene expression in chickens

Methionine (Met) is an essential and first limiting amino acid in the poultry diet that plays a significant role in chicken embryonic development and growth. The present study examined the effect of in ovo injection of DL-Met and L-Met sources and genotypes on chicken embryonic-intestinal development and health. Fertilized eggs of the two genotypes, TETRA-SL layer hybrid (TSL) - commercial layer hybrid and Hungarian Partridge colored hen breed (HPC) - a native genotype, were randomly distributed into four treatments for each genotype. The treatment groups include the following: 1) control non-injected eggs (NoIn); 2) saline-injected (SaIn); 3) DL-Met injected (DLM); and 4) L-Met injected (LM). The in ovo injection was carried out on 17.5 d of embryonic development; after hatching, eight chicks per group were sacrificed, and the jejunum was extracted for analysis. The results showed that both DLM and LM groups had enhanced intestinal development as evidenced by increased villus width, villus height, and villus area (P < 0.05) compared to the control. The DLM group had significantly reduced crypt depth, glutathione content (GSH), glutathione S-transferase 3 alpha (GST3), occludin (OCLN) gene expression and increased villus height to crypt depth ratio in the TSL genotype than the LM group (P < 0.05). The HPC genotype has overexpressed insulin-like growth factor 1 (IGF1) gene, tricellulin (MD2), occludin (OCLN), superoxide dismutase 1 (SOD1), and GST3 genes than the TSL genotype (P < 0.05). In conclusion, these findings showed that in ovo injection of Met enhanced intestinal development, and function, with genotypes responding differently under normal conditions. Genotypes also influenced the expression of intestinal antioxidants, tight junction, and growth-related genes.

Antibody-mediated targeting of Claudins in cancer

Tight junctions (TJs) are large intercellular adhesion complexes that maintain cell polarity in normal epithelia and endothelia. Claudins are critical components of TJs, forming homo- and heteromeric interaction between adjacent cells, which have emerged as key functional modulators of carcinogenesis and metastasis. Numerous epithelial-derived cancers display altered claudin expression patterns, and these aberrantly expressed claudins have been shown to regulate cancer cell proliferation/growth, metabolism, metastasis and cell stemness. Certain claudins can now be used as biomarkers to predict patient prognosis in a variety of solid cancers. Our understanding of the distinct roles played by claudins during the cancer progression has progressed significantly over the last decade and claudins are now being investigated as possible diagnostic markers and therapeutic targets. In this review, we will summarize recent progress in the use of antibody-based or related strategies for targeting claudins in cancer treatment. We first describe pre-clinical studies that have facilitated the development of neutralizing antibodies and antibody-drug-conjugates targeting Claudins (Claudins-1, -3, -4, -6 and 18.2). Next, we summarize clinical trials assessing the efficacy of antibodies targeting Claudin-6 or Claudin-18.2. Finally, emerging strategies for targeting Claudins, including Chimeric Antigen Receptor (CAR)-T cell therapy and Bi-specific T cell engagers (BiTEs), are also discussed.

The impact of exogenous vasoactive intestinal polypeptide on inflammatory responses and mRNA expression of tight junction genes in lambs fed a high-grain diet

This study assessed the impact of administering vasoactive intestinal polypeptide (VIP) on inflammation and intestinal VIP and tight junction mRNA expression in lambs fed grain-based finishing diets. Sixteen wether lambs (69.6 ± 1.9 kg) were individually housed, adapted to a corn-based diet containing no forage, and randomly assigned to 2 treatment groups. Lambs were intraperitoneally injected every other day for 28 d with either saline (0.9% NaCl) with no VIP (n = 8; control) or saline with VIP (n = 8; 1.3 nmol/kg BW). Blood samples were collected weekly for analysis of cytokine concentrations, and on days 0 and 28 for lipopolysaccharide (LPS), and LPS-binding protein (LBP) concentrations. Upon completion of the treatment period, lambs were euthanized and gastrointestinal tissues, including rumen, jejunum, cecum, and colon samples, were collected for analysis of the expression of tight junction mRNA (claudin-1, claudin-4, occludin, and ZO-1), endogenous VIP, and VIP receptor (VPAC-1). No treatment effects (P ≥ 0.38) were observed for VIP and VPAC-1 mRNA expression in the colon. Supplementation with VIP did not influence (P ≥ 0.28) the expression of claudin-1, claudin-4, occludin, and ZO-1 tight junction mRNA in the rumen, jejunum, cecum, and colon. Lambs treated with VIP had greater (P ≤ 0.01) plasma concentrations of the anti-inflammatory cytokines, IL-10 and IL-36RA. There were treatment-by-day interactions observed (P ≤ 0.02) for concentrations of the pro-inflammatory cytokines, MIP-1α and MIP-1β. Lambs that did not receive VIP had greater serum concentrations of LPS (P = 0.05) than the lambs receiving VIP. These data suggest that VIP administration may not influence tight junction mRNA expression but may decrease LPS concentrations and thus inflammation in lambs fed a grain-based diet.

Impact of maternal live yeast supplementation to sows on intestinal inflammatory cytokine expression and tight junction proteins in suckling and weanling piglets

Recent studies have highlighted the importance of maternal nutrition during gestation and lactation in modulating the gastrointestinal development and health of offspring. Therefore, the objective of this study was to determine the effects of live yeast (LY) supplementation to sows during late gestation and throughout lactation on markers of gut health of piglets prior to weaning and immediately postweaning. On day 77 of gestation, forty sows were allotted based on parity and expected farrowing dates to two dietary treatments: without (CON) or with (LY) supplementation at 0.05% and 0.1% of diet during gestation and lactation, respectively. On postnatal days (PND) 0, 10, 18, and postweaning days (PWD) 7 and 14, one piglet from each of 10 sows per treatment were selected for intestinal tissue collection (n = 10). Real-time PCR and western blotting analyses were used to determine the mucosal expression of immune and antioxidant-regulatory genes and tight junction markers of gut health in the duodenum, jejunum, and ileum. Inflammatory and tight junction markers on PND 0 were not affected by maternal dietary treatment. On PND 18, maternal LY supplementation increased (P < 0.05) mRNA expression of interleukin (IL)-6 and tended (P = 0.08) to increase expression of IL-10 in the ileal muocsa. Maternal LY supplementation also increased (P < 0.05) expression of IL-1β in the ileal mucosa on PWD 14. Likewise, expression of superoxide dismutase (SOD) 1 was increased (P < 0.05) by LY on PND 10, 18, and PWD 14, with a tendency (P = 0.09) for a greater mRNA abundance of catalase on PND 14 in the ileal mucosa. Compared to CON piglets, LY piglets had a higher (P < 0.05) protein abundance of E-cadherin in the jejunal mucosa on PND 0, PWD 7, and PWD 14. Levels of occludin and claudin-4 were also higher (P < 0.05) in the jejunum of LY piglets on PWD 14. No differences were found in jejunal histomorphological measurements between treatments. In conclusion, this study shows that maternal LY supplementation affects key markers of gut health and development in the offspring that may impact the future growth potential and health of newborn piglets.

The Intervention of Probiotics on Type 2 Diabetes Mellitus in Animal Models

Type 2 diabetes accounts for more than 90% of diabetes patients with the incidence and prevalence continuously rising globally. As a prospective therapy strategy for type 2 diabetes, probiotics have shown beneficial effects both in animal experiments and human clinical trials. This review summarizes the commonly used animal models in probiotic intervention research and presents the evidence and mechanism of diabetes intervention with probiotics in these animal models. Probiotics can help maintain glucose homeostasis, improve lipid metabolism, promote the production of short-chain fatty acids, and reduce inflammatory reactions in animal models. However, the clinical translation of benefits from probiotics is still challenged by intrinsic differences between experimental animal models and humans, and the application of humanized non-rodent diabetic animal models may contribute to the clinical translation of probiotics in the future.

Endothelial Dysfunction in Obesity and Therapeutic Targets

Parallel to the increasing prevalence of obesity in the world, the mortality from cardiovascular disease has also increased. Low-grade chronic inflammation in obesity disrupts vascular homeostasis, and the dysregulation of adipocyte-derived endocrine and paracrine effects contributes to endothelial dysfunction. Besides the adipose tissue inflammation, decreased nitric oxide (NO)-bioavailability, insulin resistance (IR), and oxidized low-density lipoproteins (oxLDLs) are the main factors contributing to endothelial dysfunction in obesity and the development of cardiorenal metabolic syndrome. While normal healthy perivascular adipose tissue (PVAT) ensures the dilation of blood vessels, obesity-associated PVAT leads to a change in the profile of the released adipo-cytokines, resulting in a decreased vasorelaxing effect. Higher stiffness parameter β, increased oxidative stress, upregulation of pro-inflammatory cytokines, and nicotinamide adenine dinucleotide phosphate (NADP) oxidase in PVAT turn the macrophages into pro-atherogenic phenotypes by oxLDL-induced adipocyte-derived exosome-macrophage crosstalk and contribute to the endothelial dysfunction. In clinical practice, carotid ultrasound, higher leptin levels correlate with irisin over-secretion by human visceral and subcutaneous adipose tissues, and remnant cholesterol (RC) levels predict atherosclerotic disease in obesity. As a novel therapeutic strategy for cardiovascular protection, liraglutide improves vascular dysfunction by modulating a cyclic adenosine monophosphate (cAMP)-independent protein kinase A (PKA)-AMP-activated protein kinase (AMPK) pathway in PVAT in obese individuals. Because the renin-angiotensin-aldosterone system (RAAS) activity, hyperinsulinemia, and the resultant IR play key roles in the progression of cardiovascular disease in obesity, RAAS-targeted therapies contribute to improving endothelial dysfunction. By contrast, arginase reciprocally inhibits NO formation and promotes oxidative stress. Thus, targeting arginase activity as a key mediator in endothelial dysfunction has therapeutic potential in obesity-related vascular comorbidities. Obesity-related endothelial dysfunction plays a pivotal role in the progression of type 2 diabetes (T2D). The peroxisome proliferator-activated receptor gamma (PPARγ) agonist, rosiglitazone (thiazolidinedione), is a popular drug for treating diabetes; however, it leads to increased cardiovascular risk. Selective sodium-glucose co-transporter-2 (SGLT-2) inhibitor empagliflozin (EMPA) significantly improves endothelial dysfunction and mortality occurring through redox-dependent mechanisms. Although endothelial dysfunction and oxidative stress are alleviated by either metformin or EMPA, currently used drugs to treat obesity-related diabetes neither possess the same anti-inflammatory potential nor simultaneously target endothelial cell dysfunction and obesity equally. While therapeutic interventions with glucagon-like peptide-1 (GLP-1) receptor agonist liraglutide or bariatric surgery reverse regenerative cell exhaustion, support vascular repair mechanisms, and improve cardiometabolic risk in individuals with T2D and obesity, the GLP-1 analog exendin-4 attenuates endothelial endoplasmic reticulum stress.

Lipid-based nanoparticles for drug delivery in Parkinson's disease

Parkinson's disease (PD) is a neurodegenerative disorder that predominantly affects dopaminergic neurons in the substantia nigra and ventral tegmental area, resulting in symptoms such as tremors, muscle rigidity, bradykinesia, and potential cognitive and affective disturbances. The effective delivery of pharmacological agents to the central nervous system is hindered by various factors, including the restrictive properties of the blood‒brain barrier and blood‒spinal cord barrier, as well as the physicochemical characteristics of the drugs. Traditional drug delivery methods may not provide the therapeutic concentrations necessary for functional restoration in PD patients. However, lipid-based nanoparticles (NPs) offer new possibilities for enhancing the bioavailability of established treatment regimens and developing innovative therapies that can modify the course of the disease. This review provides a concise overview of recent advances in lipid-based NP strategies aimed at mitigating specific pathological mechanisms relevant to PD progression. This study also explores the potential applications of nanotechnological innovations in the development of advanced treatment modalities for individuals with PD.

Breaking the barriers: the role of gut homeostasis in Metabolic-Associated Steatotic Liver Disease (MASLD)

Obesity, insulin resistance (IR), and the gut microbiome intricately interplay in Metabolic-associated Steatotic Liver Disease (MASLD), previously known as Non-Alcoholic Fatty Liver Disease (NAFLD), a growing health concern. The complex progression of MASLD extends beyond the liver, driven by "gut-liver axis," where diet, genetics, and gut-liver interactions influence disease development. The pathophysiology of MASLD involves excessive liver fat accumulation, hepatocyte dysfunction, inflammation, and fibrosis, with subsequent risk of hepatocellular carcinoma (HCC). The gut, a tripartite barrier, with mechanical, immune, and microbial components, engages in a constant communication with the liver. Recent evidence links dysbiosis and disrupted barriers to systemic inflammation and disease progression. Toll-like receptors (TLRs) mediate immunological crosstalk between the gut and liver, recognizing microbial structures and triggering immune responses. The "multiple hit model" of MASLD development involves factors like fat accumulation, insulin resistance, gut dysbiosis, and genetics/environmental elements disrupting the gut-liver axis, leading to impaired intestinal barrier function and increased gut permeability. Clinical management strategies encompass dietary interventions, physical exercise, pharmacotherapy targeting bile acid (BA) metabolism, and microbiome modulation approaches through prebiotics, probiotics, symbiotics, and fecal microbiota transplantation (FMT). This review underscores the complex interactions between diet, metabolism, microbiome, and their impact on MASLD pathophysiology and therapeutic prospects.

Stepwise modulation of apical orientational cell adhesions for vertebrate neurulation

Neurulation transforms the neuroectoderm into the neural tube. This transformation relies on reorganising the configurational relationships between the orientations of intrinsic polarities of neighbouring cells. These orientational intercellular relationships are established, maintained, and modulated by orientational cell adhesions (OCAs). Here, using zebrafish (Danio rerio) neurulation as a major model, we propose a new perspective on how OCAs contribute to the parallel, antiparallel, and opposing intercellular relationships that underlie the neural plate-keel-rod-tube transformation, a stepwise process of cell aggregation followed by cord hollowing. We also discuss how OCAs in neurulation may be regulated by various adhesion molecules, including cadherins, Eph/Ephrins, Claudins, Occludins, Crumbs, Na+ /K+ -ATPase, and integrins. By comparing neurulation among species, we reveal that antiparallel OCAs represent a conserved mechanism for the fusion of the neural tube. Throughout, we highlight some outstanding questions regarding OCAs in neurulation. Answers to these questions will help us understand better the mechanisms of tubulogenesis of many tissues.

Fusobacterium nucleatum putatively affects the alveoli by disrupting the alveolar epithelial cell tight junction, enlarging the alveolar space, and increasing paracellular permeability

Fusobacterium nucleatum (Fn) is abundant in the human oral cavity and has been associated with periodontal disease, which in-turn has been linked to respiratory disease development. Tight junctions (TJs) line the airway and alveoli surfaces serving as a first line of defense against multiple pathogens. Fn has already been linked to respiratory diseases, however, how Fn affects the alveolar TJ was not fully elucidated. Here, we designed and analyzed a TJ network, grew Fn cells and inoculated it in vitro (16HBE and primary cells) and in vivo (mice lung), measured transepithelial electrical resistance, performed RT-PCR, checked for in vitro cell and mice lung permeability, and determined air space size through morphometric measurements. We found that Fn can potentially affect TJs proteins that are directly exposed to the alveolar surface. Additionally, Fn could possibly cause neutrophil accumulation and an increase in alveolar space. Moreover, Fn putatively may cause an increase in paracellular permeability in the alveoli.

Oral vancomycin treatment suppresses gut trypsin activity and preserves intestinal barrier function during EAE

Studies have reported increased intestinal permeability in multiple sclerosis (MS) patients and its mouse model experimental autoimmune encephalomyelitis (EAE). However, the mechanisms driving increased intestinal permeability that in turn exacerbate neuroinflammation during EAE remain unclear. Here we showed that vancomycin preserved the integrity of the intestinal barrier, while also suppressing gut trypsin activity, enhancing the relative abundance of specific Lactobacilli and ameliorating disease during EAE. Furthermore, Lactobacilli enriched in the gut of vancomycin-treated EAE mice at day 3 post immunization negatively correlated with gut trypsin activity and EAE severity. In untreated EAE mice, we observed increased intestinal permeability and increased intestinal protease activated receptor 2 (PAR2) expression at day 3 post immunization. Prior studies have shown that trypsin increases intestinal permeability by activating PAR2. Our results suggest that the interaction between intestinal PAR2 and trypsin may be a key modulator of intestinal permeability and disease severity during EAE.