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As the non-steroidal anti-inflammatory drugs (NSAIDs) are typically used in the treatment of chronic conditions, the incidence of NSAID-induced enteropathy is increasing. Given the challenges associated with discontinuing NSAIDs, effective preventive and treatment strategies are crucial. We assessed the effect of tegoprazan on NSAID-induced enteropathy. Human epithelial cells (HIEC-6, HT-29, and Caco-2) were treated with indomethacin and tegoprazan. Cell viability, expression levels of tight-junction proteins, levels of proinflammatory cytokines, and apoptosis were assessed by conducting MTT assays, RT-PCR, western blotting, and immunofluorescence staining, respectively. Tegoprazan significantly ameliorated the inhibition of cell proliferation induced by indomethacin. Tegoprazan also mitigated the suppression of occludin and ZO-1 expression by indomethacin, thereby restoring intestinal permeability. Additionally, tegoprazan reversed the indomethacin-induced elevation of the levels of proinflammatory cytokines and the rate of apoptosis of small intestinal epithelial cells. Our findings indicate that tegoprazan exerts a protective effect against NSAID-induced injury to small intestinal epithelial cells. The effect involves enhancement of the expression levels of tight junction proteins and the suppression of inflammation and apoptosis., (© 2024. The Author(s).)

The blood-brain barrier (BBB) strictly limits the entry of most exogenous therapeutic drugs into the brain, which brings great challenges to the drug treatment of refractory central diseases, including the treatment of ischemic stroke. Our previous studies have shown that specific mode electroacupuncture stimulation (SMES) can temporarily open the BBB, but with the mechanisms largely unknown. This study explored whether SMES opens the BBB in the infarcted border zone of rats during middle cerebral artery occlusion/reperfusion recovery, and whether this is related to p65 or vascular endothelial growth factor A (VEGFA) modulation of tight junction protein expression through in vivo and in vitro studies. Evans blue, FITC-dextran, mouse-derived nerve growth factor (NGF), and transendothelial electrical resistance values were used to evaluate the permeability of the BBB. Additionally, microvascular endothelial cells and astrocytes were utilized for in vitro study. Immunofluorescence, immunohistochemistry, western blot, and ELISA were employed to assess related protein expression. SMES significantly increased vascular permeability for Evans blue and NGF in the infarcted border zone, and increased the expression of VEGFA by activating p-p65, thereby reducing the expression of tight junction proteins Occludin and ZO-1. Correspondingly, oxygen glucose deprivation/reoxygenation activated p-p65 in and induced VEGFA secretion from astrocytes in vitro. Their conditioned medium reduced the expression of Occludin in bEnd.3 cells and increased the permeability of FITC-dextran. The mechanism of SMES opening infarcted border zone BBB is partly related to its actions on p65, VEGFA, and tight junction proteins., (Copyright © 2024 Wolters Kluwer Health, Inc. All rights reserved.)

Neurodegenerative diseases are often accompanied by neuroinflammation and impairment of the blood-brain barrier (BBB) mediated by activated glial cells through their release of proinflammatory molecules. To study the effects of glial cells on mouse brain endothelial cells (mBECs), we developed an in vitro BBB model with inflammation by preactivating mixed glial cells (MGCs) with lipopolysaccharide (LPS) before co-culturing with mBECs to study the influence of molecules released by activated MGCs. The response of the mBECs to activated MGCs was compared to direct stimulation with LPS. The cytokine profile of activated MGCs was analyzed together with their effects on the mBEC's integrity, expression of tight junction proteins, adhesion molecules, and BBB-specific transport proteins. Stimulation of MGCs significantly upregulated mRNA expression and secretion of several pro-inflammatory cytokines. Co-culturing mBECs with pre-stimulated MGCs significantly affected the barrier integrity of mBECs similar to direct stimulation with LPS. The gene expression levels of tight junction proteins were unaltered, but tight junction proteins revealed rearrangements with respect to subcellular distribution. Compared to direct stimulation with LPS, the expression of cell-adhesion molecules was significantly increased when mBECs were co-cultured with prestimulated MGCs and thus pre-activating MGCs transforms mBECs into a proinflammatory phenotype., (© 2024. The Author(s).)

Previous studies have indicated that oridonin is a promising candidate for therapeutic intervention in a range of inflammatory diseases. The objective of this study was to investigate the protective mechanism of oridonin in chronic rhinosinusitis with nasal polyp (CRSwNP). In nasal polyp (NP) mice model, cigarette smoke (CS) induced polypoid changes compared to previous modeling methods. Compared with CS-treated mice, oridonin reduced polypoid changes, goblet cell count, and promoted the expression of tight junction proteins (ZO-1, occludin, claudin-1) and production of autophagosomes. Following treatment with oridonin, the levels of OVA-specific IgE, IL-6, IFN-γ, IL-5, IL-13 and IL-17A in serum were observed to decrease; the levels of TGF-β1, matrix metalloproteinase 2 (MMP2), MMP7, MMP9 and MMP12 levels in nasal lavage fluid were reduced, while tissue inhibitor of metalloproteinase-1 (TIMP-1) levels were increased. Furthermore, the aforementioned alterations in the mouse model were reversed by 3-methyladenine (3-MA), an autophagy inhibitor. In vitro, cigarette smoke extract (CSE) was observed to decrease the expression of tight junction proteins, the production of autophagosomes, and to reduce the expression of LC3-II and Beclin-1, accompanied by an increase in P62 expression. In addition, oridonin was observed to reverse CSE-induced epithelial barrier damage, and was associated with autophagy and the PI3K/AKT/mTOR pathway. In conclusion, oridonin was demonstrated to improve the damage of the nasal epithelial barrier induced by CS through the promotion of autophagy, which may represent a novel therapeutic option for the treatment of CRSwNP., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Masson SAS.. All rights reserved.)

The unknown mechanism that controls intestinal barrier dysfunction in individuals with Crohn's disease (CD) plays a crucial role in the onset of intestinal inflammation. Testin, an intercellular linker protein, has the potential to protect epithelial barrier function. This study aimed to analyse the effects of Testin on CD-like colitis and explore the possible underlying mechanism. Colon samples from CD patients and trinitrobenzene-sulfonic acid (TNBS)-treated mice were collected to examine changes in Testin expression. To assess the therapeutic effects of Testin on CD-like colitis in mice, we examined the symptoms of enteritis, performed histological analysis, and evaluated intestinal barrier permeability. The ability of Testin to stabilize tight junction (TJ) proteins was investigated via immunofluorescence and western blotting. We conducted in vivo and in vitro experiments using colonic organoids and blocking techniques to explore how Testin safeguards the integrity of the intestinal barrier. Testin expression was downregulated in the colons of CD patients and TNBS-treated mice. Increasing Testin expression led to amelioration of colitis symptoms and reduced the production of inflammatory cytokines in the colons of TNBS-induced colitis model mice. Furthermore, increased Testin expression resulted in decreased depletion of TJ proteins (ZO-1 and Claudin-1) and promoted the effectiveness of the intestinal barrier in mice with TNBS-induced colon damage and in lipopolysaccharide (LPS)-stimulated colonic organoids. Elevated Testin levels inactivated the JNK/P38 signalling pathway, potentially contributing to the beneficial impact of Testin on the intestinal barrier. Testin can inhibit the loss of TJ proteins in CD mice by inactivating the JNK/P38 pathway. These findings help to clarify how Testin alleviates CD-like colitis in mice by protecting intestinal barrier function. These findings could lead to the use of a new treatment approach for CD in clinical practice., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

In piglets, oxidative stress can exacerbate gut injury caused by pathogens. C-Jun amino-terminal kinase (JNK) is associated with oxidative stress-induced damage to intestinal epithelial barrier. However, it is unclear whether oxidative stress can increase gut injury by Clostridium perfringens type A (CpA) and whether JNK mediates this process. We aimed to investigate if and how the JNK can regulate the effect of oxidative stress on gut injury induced by CpA infection. In this study, the oxidative stress in IPEC-J2 cells was modeled, and the changes in the susceptibility of IPEC-J2 cells to CpA were examined after treatment of oxidative stressed IPEC-J2 cells with JNK inhibitor (SP600125) and JNK siRNA. Pre-injection with the SP600125 solution was also carried out in oxidative stressed mice, followed by CpA infection. Results indicated that compared to that in the Control group, IPEC-J2 cells under oxidative stress showed reduced transmembrane resistance, degraded tight junction (TJ) proteins, increased membrane permeability, and enhanced CpA infection, all of which were reversed by inhibiting or interfering with JNK expression. Similarly, compared to that in the Control group, mice under oxidative stress showed degradation of jejunal TJ proteins, increased intestinal permeability and barrier damage by CpA, while mice pre-injected with the SP600125 solution showed alleviation of these alterations. These results suggested that oxidative stress enhanced the infection of IPEC-J2 cells and the gut injury caused by CpA, which was mediated by JNK. This study provides important insights regarding the mechanism by which oxidative stress enhanced intestinal damage by CpA., Competing Interests: Declaration of Competing Interest The author(s) declare no potential conflicts of interest with respect to the research, authorship and/or publication of this article., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Background: The polymorphism of the apolipoprotein E (ApoE) gene has been implicated in both the susceptibility to neurodegenerative disease and the prognosis of traumatic brain injury (TBI). However, the influence of ApoE on the risk of hemorrhagic transformation (HT) after acute ischemic stroke remains inconclusive. The present study aimed to investigate the potential impact of ApoE deficiency on the risk of hyperglycemia-associated HT and to elucidate the underlying mechanisms., Methods: Wild-type (WT) and ApoE knockout (ApoE -/- ) mice were injected with 50 % glucose to induce hyperglycemia and subsequently subjected to 90 min of intraluminal middle cerebral artery occlusion (MCAO). The mortality, neurological function, HT incidence and HT grading-score were evaluated at 24 hours after reperfusion. To evaluate the integrity of blood-brain barrier (BBB), the immunoglobulin G (IgG) leakage and the protein expressions of tight junctions (TJs) were detected using immunofluorescent staining and western blotting. Finally, the levels of matrix metalloproteinases (MMP)-2/9, microglial activation and proinflammatory mediators were investigated using immunofluorescent staining and western blotting., Results: ApoE -/- mice exhibited increased mortality and exacerbated neurological impairment, concomitant with more severe hyperglycemia-associated HT 24 hours post-reperfusion. Meanwhile, ApoE deficiency exacerbated the disruption of BBB, characterized by increased leakage of IgG, aggravated degradation of TJs and microvascular basement membranes. Furthermore, ApoE deficiency further aggravated the upregulation of MMP-2/9 and microglia-triggered neuroinflammation., Conclusions: Our findings demonstrate that the absence of ApoE exacerbates neurological impairment and hyperglycemia-associated HT in ischemic stroke mice, which is closely associated with MMP-2/9 signaling and neuroinflammation-mediated disruption of BBB., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Background Hailey-Hailey disease (HHD) is a rare, autosomal dominant, hereditary skin disorder characterised by epidermal acantholysis. The HHD-associated gene ATPase calcium-transporting type 2C member 1 (ATP2C1) encodes the protein secretory pathway Ca2+ ATPase1 (SPCA1), playing a critical role in HHD pathogenesis. Aims We aimed to investigate the effect of ATP2C1 knockdown on keratinocytes that mimicked acantholysis in HHD. Methods Immunohistochemistry (IHC) was employed to evaluate the levels of cytoskeletal and tight junction proteins such as SPCA1, P-cofilin, F-actin, claudins, occludin, and zonula occludens 1 in the skin biopsies of patients with HHD. Subsequently, the expression of these proteins in cultured ATP2C1 knockdown keratinocytes was analysed using Western blotting and immunofluorescence. Furthermore, we assessed the proliferation, apoptosis, and intracellular Ca2+ concentrations in the ATP2C1-knocked keratinocytes. Results The results showed decreased levels of these proteins (SPCA1, P-cofilin, F-actin, claudins, occluding, and zonula occludens 1) in HHD skin lesions. Moreover, their levels decreased in human keratinocytes transfected with ATP2C1 short hairpin RNA, accompanied by morphological acantholysis. Furthermore, the proliferation and apoptosis of the keratinocytes, as well as intracellular calcium concentrations in these cells, were not affected. Limitations The limitations of this study are the absence of animal experiments and the failure to explore the relationship between skeletal and tight junction proteins. Conclusion The present study indicated that ATP2C1 inhibition led to abnormal levels of the cytoskeletal and tight junction proteins in the keratinocytes. Therefore, keratinocytes can mimic HHD-like acantholysis and serve as an in vitro model, helping develop treatment strategies against HHD.

The intestinal barrier weakens and chronic gut inflammation occurs in old age, causing age-related illnesses. Recent research shows that low-molecular-weight heparin (LMWH), besides anticoagulation, also has anti-inflammatory and anti-apoptotic effects, protecting the intestinal barrier. This study aims to analyze the effect of LMWH on the intestinal barrier of old male rodents. This study assigned Sprague-Dawley male rats to four groups: young (3 months), young + LMWH, old (20 months), and old + LMWH. The LMWH groups received 1 mg/kg LMWH via subcutaneous injection for 7 days. Optical and transmission electron microscopy (TEM) were used to examine morphological changes in intestinal mucosa due to aging. Intestinal permeability was measured using fluorescein isothiocyanate (FITC)-dextran. ELISA kits were used to measure serum levels of IL-6 and IL-1β, while Quantitative RT-PCR detected their mRNA levels in intestinal tissues. Western blotting and immunohistochemistry (IHC) evaluated the tight junction (TJ) protein levels such as occludin, zonula occludens-1 (ZO-1), and claudin-2. Western blotting assessed the expression of the apoptosis marker cleaved caspase 3, while IHC was used to detect LGR5+ intestinal stem cells. The intestinal permeability of aged rats was significantly higher than that of young rats, indicating significant differences. With age, the protein levels of occludin and ZO-1 decreased significantly, while the level of claudin-2 increased significantly. Meanwhile, our study found that the levels of IL-1β and IL-6 increased significantly with age. LMWH intervention effectively alleviated age-related intestinal barrier dysfunction. In aged rats treated with LMWH, the expression of occludin and ZO-1 proteins in the intestine increased, while the expression of claudin-2 decreased. Furthermore, LMWH administration in aged rats resulted in a decrease in IL-1β and IL-6 levels. LMWH also reduced age-related cleaved caspase3 expression, but IHC showed no difference in LGR5+ intestinal stem cells between groups. Research suggests that LMWH could potentially be a favorable therapeutic choice for age-related diseases associated with intestinal barrier dysfunction, by protecting TJ proteins, reducing inflammation, and apoptosis., (© 2024. The Author(s), under exclusive licence to Springer Nature B.V.)

The weaning phase in piglets causes significant physiological stress, disrupts intestinal integrity and reduces productivity, necessitating strategies to improve intestinal health and nutrient absorption. While current research highlights the role of diet in mitigating these adverse effects, identifying effective dietary supplements remains a challenge. This study evaluated the effects of Hermetia illucens (HI) larvae meal and astaxanthin (AST) on the intestinal histology of weaned piglets. In a controlled experiment, 48 weaned piglets were divided into six groups and received varying levels of HI larval meal (2.5% and 5%) and AST in their diets. The methodology involved comprehensive histological examinations of the small intestine, assessing absorption area, villi elongation, crypt depth, goblet cells, enterocytes and expression of ileal tight junction (TJ) proteins. The study found that HI larval meal significantly improved nutrient absorption in the jejunum and ileum (p < 0.001), thereby enhancing feed conversion. AST supplementation increased the number of enterocytes (p < 0.001). Both HI larval meal and AST positively affected intestinal morphology and function, increasing muscularis muscle mass and villi elongation (p < 0.001 and p < 0.05, respectively). The 2.5% HI meal improved the villi length to crypt depth ratio and slightly increased the goblet cell count (both p < 0.05). Ki-67 antibody analysis showed increased cell proliferation in the duodenal and jejunal crypts, particularly with the 2.5% HI meal (p < 0.001). Insect meal did not affect TJ protein expression, indicating that it had no effect on intestinal permeability. These findings suggest that HI larval meal and AST can enhance the intestinal wellness and productivity of weaned piglets., (© 2024 Wiley‐VCH GmbH. Published by John Wiley & Sons Ltd.)

Introduction: Tight junctions (TJs) and their constituent proteins play pivotal roles in cellular physiology and anatomy by establishing functional boundaries within and between neighboring cells. While the involvement of TJ proteins, such as claudins, in cancer is extensively studied, studies highlighting their interaction with immune system are still meager. Studies indicate that alterations in cytokines and immune cell populations can affect TJ proteins, compromising TJ barrier function and exacerbating pro-inflammatory conditions, potentially leading to epithelial cell malignancy. Disrupted TJs in established tumors may foster a pro-tumor immune microenvironment, facilitating tumor progression, invasion, epithelial-to-mesenchymal transition and metastasis. Although previous literature contains many studies describing the involvement of TJs in pathogenesis of malignancies their role in modulating the immune microenvironment of tumors is just beginning to be unleashed., Areas Covered: This article for the first time attempts to discern the importance of interaction between TJs and immune microenvironment in malignancies. To achieve the above aim a thorough search of databases like PubMed and Google Scholar was conducted to identify the recent and relevant articles on the topic., Expert Opinion: Breaking the vicious cycle of dysbiosis/infections/chemical/carcinogen-induced inflammation-TJ remodeling-malignancy-TJ dysregulation-more inflammation can be used as a strategy to complement the effect of immunotherapies in various malignancies.

Japanese encephalitis virus (JEV) is a neurotropic and neuroinvasive flavivirus causing viral encephalitis, which seriously threatens the development of animal husbandry and human health. DNA methylation is a major epigenetic modification involved in viral pathogenesis, yet how DNA methylation affects JEV infection remains unknown. Here, we show genome-wide DNA methylation profiles in the brains of JEV-infected mice compared to mock-infected mice. JEV can significantly increase the overall DNA methylation levels in JEV-infected mouse brains. A total of 14,781 differentially methylated regions associated genes (DMGs) have been identified. Subsequently, KEGG pathway analysis suggested that DNA methylation modulates the tight junction signaling pathway, which can potentially impact the permeability of the blood-brain barrier (BBB). We demonstrate that hypermethylation of the tight junction gene Afdn promoter inhibited AFDN expression and increased monolayer permeability of mouse brain microvascular endothelial (bEnd.3) cells in an in vitro transwell assay. Collectively, this study reveals that DNA methylation is increased in a murine Japanese encephalitis model and that modulation of Afdn expression promotes BBB permeability., (© 2024. The Author(s).)

Background: Lactiplantibacillus species are extensively studied for their ability to regulate host immune responses and functional therapeutic potentials. Nevertheless, there is a lack of understanding on the mechanisms of interactions with the hosts during immunoregulatory activities., Methods: Two Lactiplantibacillus plantarum strains MKMB01 and MKMB02 were tested for probiotic potential following Indian Council of Medical Research (ICMR) guidelines. Human colorectal adenocarcinoma cells such as HT-29, caco-2, and human monocytic cell THP-1 were also used to study the potential of MKMB01 and MKMB02 in regulating the host immune response when challenged with enteric pathogen Salmonella enterica typhimurium. Cells were pre-treated with MKMB01 and MKMB02 for 4 h and then stimulated with Salmonella. qRT-PCR and ELISA were used to analyze the genes and protein expression. Confocal microscopy and field emission scanning electron microscopy (FESEM) were used to visualize the effects. An Agilent Seahorse XF analyzer was used to determine real-time mitochondrial functioning., Results: Both probiotic strains could defend against Salmonella by maintaining gut integrity via expressing tight junction proteins (TJPs), MUC-2, and toll-like receptors (TLRs) negative regulators such as single Ig IL-1-related receptor (SIGIRR), toll-interacting protein (Tollip), interleukin-1 receptor-associated kinase (IRAK)-M, A20, and anti-inflammatory transforming growth factor-β and interleukin-10. Both strains also downregulated the expression of pro-inflammatory cytokines/chemokines interleukin-1β, monocyte chemoattractant protein (MCP)-1, tumor necrosis factor-alpha (TNF-α), interleukin 6, and nitric oxide (NO). Moreover, TNF-α sheddase protein, a disintegrin and metalloproteinase domain 17 (ADAM17), and its regulator iRhom2 were downregulated by both strains. Moreover, the bacteria also ameliorated Salmonella-induced mitochondrial dysfunction by restoring bioenergetic profiles, such as non-mitochondrial respiration, spare respiratory capacity (SRC), basal respiration, adenosine triphosphate (ATP) production, and maximal respiration., Conclusions: MKMB01 and MKMB02 can reduce pathogen-induced gut-associated disorders and therefore should be further explored for their probiotic potential., (© 2024. The Author(s).)

Adiponectin (APN), a vasoactive cytokine produced by adipocytes, has emerged as a critical player in retinal diseases. Renowned for its antioxidant, anti-angiogenic, and anti-inflammatory properties, APN levels are closely linked to metabolic disorders, such as insulin resistance, obesity, and diabetic retinopathy (DR). Our previous work demonstrated that APN is similar in efficiency as Avastin in limiting neovascularization in retinal endothelial cells. In this study, we analyzed the effect of APN on retinal epithelial cells to understand its potential impact on eye-related pathologies. Overexpression of APN in ARPE-19 cells predominantly yielded the MMW-APN form, accompanied by increased expression of pro-fibrotic markers and decreased levels of tight junction (TJ) proteins, ZO-1, and Occludin. Further, confocal imaging revealed impaired TJ assembly and the integrity of TJ was also compromised as evidenced by the higher paracellular permeability and lower TEER. Besides, rAPN treatment in ARPE-19 cells as well triggered increased expression of pro-fibrotic markers, pro-MMP2, and enhanced cell migration and proliferation. Mechanistically, these pro-fibrotic effects were mediated by APN-induced phosphorylation of ERK1/2, causing RPE cell transdifferentiation. Furthermore, we identified that MMW-APN was the most prevalent form detected in the vitreous humor of proliferative diabetic retinopathy (PDR) patients, emphasizing the clinical relevance of our findings. Overall, our data suggest that APN, particularly its MMW form, induces epithelial-mesenchymal transition (EMT) and fibrosis in RPE cells, potentially driving the angio-fibrotic shift observed in PDR via ERK1/2 activation., (© 2024. The Author(s) under exclusive licence to Japan Human Cell Society.)

Arsenic is a widespread environmental contaminant known to accumulate in the brain, leading to cognitive impairment. However, the exact mechanisms by which arsenic causes cognitive deficits remain unclear. The present study aims to discover whether the destruction of the blood-brain barrier (BBB) mediated by matrix metalloproteinases 2 and matrix metalloproteinases 9 (MMP-2 and MMP-9) and subsequent neuronal apoptosis are involved in arsenic-induced cognitive impairment. Ninety male mice were given 0, 25, and 50 mg/L NaAsO 2 in drinking water and 30 mg/kg doxycycline hyclate (DOX, an inhibitor of MMPs) gavage for 12 weeks to observe the alterations in learning and memory of mice, the morphology of hippocampal neurons, as well as the BBB permeability and ultrastructure, the localization and expression of tight junction proteins, MMP-2, and MMP-9. Our findings indicated that arsenic exposure induced learning and memory impairment in mice, accompanied by neuronal loss and apoptosis. Furthermore, arsenic exposure increased hematogenous IgG leakage into the brain, disrupted the tight junctions, reduced the expression of Claudin5, Occludin, and ZO1 in the endothelial cells, and increased the expression of MMP-2 and MMP-9 in the endothelial cells and astrocytes. Finally, DOX intervention preserved BBB integrity, alleviated hippocampal neuronal apoptosis, and improved cognitive impairment in mice caused by arsenic exposure. Our research demonstrates that cognitive disfunction in mice induced by arsenic exposure is associated with MMP-2 and MMP-9-mediated BBB destruction and neuronal apoptosis. The current investigation provides new insights into mechanisms of arsenic neurotoxicity and suggests that MMP-2 and MMP-9 may serve as potential therapeutic targets for treating arsenic-induced cognitive dysfunction in the future., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Objective: This study aimed to investigate the expression of tight junction, its distribution pattern in oral lichen planus samples and its potential association with the severity of oral lichen planus., Materials and Methods: Cross-sectional study designs were conducted. Transcriptome sequencing was conducted using oral mucosal tissues from 22 patients with oral lichen planus and 11 healthy controls. Immunohistochemistry and quantitative reverse transcription PCR were performed to verify the expression of claudin-1, claudin-4, occludin and zonula occludens-1 in oral mucosal tissues from another 30 patients with oral lichen planus and 26 healthy controls. The relationship between tight junction protein expression and oral lichen planus severity was explored using correlation analysis., Results: 5603 and 2475 differentially expressed genes were upregulated and downregulated respectively, in oral lichen planus tissues. KEGG analysis showed that tight junctions including CLDN1, CLDN4, OCLN and TJP1 were downregulated in oral lichen planus. Claudin-1, claudin-4, occludin and zonula occludens-1 expression was verified to be significantly lower in oral lichen planus. Furthermore, correlation analyses showed that decreased occludin expression was positively related to oral lichen planus severity., Conclusion: Decreased expression of TJ barrier proteins may be associated with the development of oral lichen planus., (© 2024 Wiley Periodicals LLC.)

Although bitter receptors, known as Tas2Rs, have been identified in the testes and mature sperm, their expression in testicular Sertoli cells (SCs) and their role in recognizing harmful substances to maintain the immune microenvironment remain unknown. To explore their potential function in spermatogenesis, this study utilized TM4 cells and discovered the high expression of the bitter receptor Tas2R143 in the cells. Interestingly, when the Tas2R143 gene was knocked down for 24 and 48 h, there was a significant downregulation (P < 0.05) in the expression of tight junction proteins (occludin and ZO-1) and NF-κB. Additionally, Western blot results demonstrated that the siRNA-133+NF-κB co-treatment group displayed a significant downregulation (P < 0.05) in the expression of occludin and ZO-1 compared to both the siRNA-133 transfection group and the NF-κB inhibitors treatment group. These findings suggest that Tas2R143 likely regulates the expression of occludin and ZO-1 through the NF-κB signaling pathway and provides a theoretical basis for studying the regulatory mechanism of bitter receptors in the reproductive system, aiming to attract attention to the chemical perception mechanism of spermatogenesis., Competing Interests: Declaration of competing interest The authors declare that the research was conducted without any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024. Published by Elsevier Inc.)

Background: The choroid plexus (CP) is an understudied tissue in the central nervous system and is primarily implicated in cerebrospinal fluid (CSF) production. CP also produces numerous neurotrophic factors (NTF) which circulate to different brain regions. Regulation of NTFs in the CP during natural aging is largely unknown. Here, we investigated the age and gender-specific transcription of NTFs along with the changes in the tight junctional proteins (TJPs) and the water channel protein Aquaporin (AQP1)., Methods: Male and female mice were used for our study. Age-related transcriptional changes were analyzed using quantitative PCR at three different time points: mature adult, middle-aged, and aged. Transcriptional changes during aging were further confirmed with digital droplet PCR. Additionally, we used immunohistochemical analysis (IHC) for the evaluation of in vivo protein expression. We further investigated the cellular phenotype of these NTFS, TJP, and water channel proteins in the mouse CP by co-labeling them with the classical vascular marker, Isolectin B4, and epithelial cell marker, Plectin., Results: Aging significantly altered NTF gene expression in the CP. Brain-derived neurotrophic factor (BDNF), Midkine (MDK), VGF, Insulin-like growth factor (IGF1), IGF2, Klotho (KL), Erythropoietin (EPO), and its receptor (EPOR) were reduced in the aged CP of males and females. Vascular endothelial growth factor (VEGF) transcription was gender-specific; in males, gene expression was unchanged in the aged CP, while females showed an age-dependent reduction. Age-dependent changes in VEGF localization were evident, from vasculature to epithelial cells. IGF2 and klotho localized in the basolateral membrane of the CP and showed an age-dependent reduction in epithelial cells. Water channel protein AQP1 localized in the tip of epithelial cells and showed an age-related reduction in mRNA and protein levels. TJP's JAM, CLAUDIN1, CLAUDIN2 and CLAUDIN5 were reduced in aged mice., Conclusions: Our study highlights transcriptional level changes in the CP during aging. The age-related transcriptional changes exhibit similarities as well as gene-specific differences in the CP of males and females. Altered transcription of the water channel protein AQP1 and TJPs could be involved in reduced CSF production during aging. Importantly, reduction in the neurotrophic factors and longevity factor Klotho can play a role in regulating brain aging., (© 2024. The Author(s).)

Background: Alterations of blood-brain barrier (BBB) and blood-spinal cord barrier have been documented in various animal models of neurodegenerative diseases and in patients. Correlations of these alterations with functional deficits suggest that repairing barriers integrity may represent a disease-modifying approach to prevent neuroinflammation and neurodegeneration induced by the extravasation of blood components into the parenchyma. Here, we screened the effect of a subcommissural organ-spondin-derived peptide (NX210c), known to promote functional recovery in several models of neurological disorders, on BBB integrity in vitro and in vivo., Methods: In vitro, bEnd.3 endothelial cell (EC) monolayers and two different primary human BBB models containing EC, astrocytes and pericytes, in static and microfluidic conditions, were treated with NX210c (1-100 µM), or its vehicle, for 4 h and up to 5 days. Tight junction (TJ) protein levels, permeability to dextrans and transendothelial electrical resistance (TEER) were evaluated. In vivo, young and old mice (3- and 21-month-old, respectively) were treated daily intraperitoneally with NX210c at 10 mg/kg or its vehicle for 5 days and their brains collected at day 6 to measure TJ protein levels by immunohistochemistry., Results: NX210c induced an increase in claudin-5 protein expression after 24-h and 72-h treatments in mouse EC. Occludin level was also increased after a 24-h treatment. Accordingly, NX210c decreased by half the permeability of EC to a 40-kDa FITC-dextran and increased TEER. In the human static BBB model, NX210c increased by ∼ 25% the TEER from 3 to 5 days. NX210c also increased TEER in the human 3D dynamic BBB model after 4 h, which was associated with a reduced permeability to a 4-kDa FITC-dextran. In line with in vitro results, after only 5 days of daily treatments in mice, NX210c restored aging-induced reduction of claudin-5 and occludin levels in the hippocampus, and also in the cortex for occludin., Conclusions: In summary, we have gathered preclinical data showing the capacity of NX210c to strengthen BBB integrity. Through this property, NX210c holds great promises of being a disease-modifying treatment for several neurological disorders with high unmet medical needs., (© 2024. The Author(s).)

The present study aimed to investigate the effect of digested total protein (DTP) from chia seed on the gut microbiota and morphology of mice fed with a high-fat diet. Forty-four male C57BL/6 mice were divided into 4 groups: AIN (standard diet), HF (high-fat diet), AIN + DTP (standard diet supplemented with 400 mg of digested chia seed protein), and HF + DTP (high-fat diet supplemented with 400 mg of digested chia seed protein) during 8 weeks. Colon morphology, tight junction's gene expression, and gut microbiota composition were evaluated. The consumption of digested chia seed protein (DTP) increased the crypts width, longitudinal and circular muscular layer. Furthermore, the AIN + DTP group enhanced the expression of tight junction proteins, including occludin and claudin, while the AIN + DTP and HF + DTP groups increase the zonula occludens expression. The α-diversity analysis showed a reduction in bacterial dominance in the HF + DTP group. All the experimental groups were grouped in different cluster, showing differences in the microbiota community in the β-diversity analyzes. The Firmicutes/Bacteroidetes ratio did not differ among the groups. The genera Olsenella and Dubosiella were increased in the AIN + DTP group, but the Oscillospiraceae &#95;unclassified was increased in the HF + DTP group. The Alistipes was increased, while the Roseburia and Akkermansia were decreased in the AIN + DTP and HF + DTP groups. Then, the consumption of DTP from chia seed improved the gut microbiota composition and mucosal integrity, counteracting the adverse effects of high-fat diet.

Background: Bipolar disorders (BD) are chronic, debilitating disorders. The blood-brain barrier (BBB) has been increasingly investigated in BD. This systematic review aimed to assess the available evidence on the relationship between BD and markers of BBB dysfunction., Methods: A systematic search in PubMed, Embase, PsycINFO, CINAHL and Web of Science was run where the primary outcomes were BBB markers such as S100B, albumin ratio, matrix metalloproteinase (MMP), cell adhesion molecule (CAM), and tight junction proteins. Techniques included blood, cerebrospinal fluid (CSF), post-mortem, genetic and imaging methods in BD compared to healthy controls., Results: 55 studies were identified, 38 of which found an association between BD and markers of BBB dysfunction. 16/29 studies found increased blood/CSF albumin ratio, S100B, CAMs or MMP levels in BD participants compared to controls. 5/19 post-mortem studies found increased levels of chondroitin sulphate proteoglycans, intercellular CAM, neurexin or claudin-5 mRNA in distinct locations throughout the brain in BD compared to controls. One imaging study identified extensive BBB leakage in 30 % of BD participants, compared to 0 % in controls., Limitations: The diversity in methodologies used in the included studies makes direct comparison of results challenging. Furthermore, imaging methods are the gold standard, but only one study used them. Other markers are only indicative of BBB permeability., Conclusions: This review suggests an association between BD and BBB dysfunction. Further research is needed to provide definite answers considering the existing literature's limitations, and to clarify whether this association provides a pathogenic mechanism, or is an epiphenomenon of BD., Competing Interests: Declaration of competing interest TP has received a speaking honorarium from Janssen for an educational lecture on an unrelated topic. TP was supported by a NIHR Clinical Lectureship. PRAS reports non-financial support from Janssen Research and Development LLC, personal fees and non-financial support from Frontiers in Psychiatry, personal fees from Allergan, funding from National Institute for Health and Care Research (NIHR) UK, and grant from H Lundbeck, outside the submitted work. No other declarations of interest exist. This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors., (Copyright © 2024 Elsevier B.V. All rights reserved.)

This study investigates the underlying mechanism through which dietary supplementation of pyrroloquinoline quinone disodium (PQQ) alleviates intestinal inflammation and cell apoptosis in piglets challenged with lipopolysaccharide (LPS). Seventy-two barrows were divided into three groups: control (CTRL), LPS challenged (LPS), and LPS challenged with PQQ supplementation (PQQ + LPS). On d 7, 11, and 14, piglets received intraperitoneal injections of LPS or 0.9% of NaCl (80 μg/kg). After a 4 h interval following the final LPS injection on d 14, blood samples were obtained, and all piglets were euthanized for harvesting jejunal samples. The results showed that dietary supplementation of PQQ improved the damage of intestinal morphology, increased the down-regulated tight junction proteins, and reduced the increase of serum diamine oxidase activity, the intestinal fatty acid binding protein, and TNF-α levels in piglets challenged with LPS ( p < 0.05). The proteomics analysis revealed a total of 141 differentially expressed proteins (DEPs), consisting of 64 up-regulated DEPs and 77 down-regulated DEPs in the PQQ + LPS group compared to the LPS group. The KEGG pathway analysis indicated enrichment of the tight junction pathway and the apoptosis pathway ( p < 0.05). Compared to the LPS group, the piglets in the PQQ + LPS group had increased levels of Bcl-2 protein, reduced positive apoptosis signals, and a decrease in the abundance of MKK 3/6 and p-p38 proteins ( p < 0.05). In conclusion, dietary supplementation of PQQ could alleviate jejunal inflammatory damage and cell apoptosis in piglets challenged with LPS through the MKK3/6-p38 signaling pathway.

The Blood-Labyrinth Barrier (BLB) is pivotal for the maintenance of lymphatic homeostasis within the inner ear, yet the intricacies of its development and function are inadequately understood. The present investigation delves into the contribution of the Mfsd2a molecule, integral to the structural and functional integrity of the Blood-Brain Barrier (BBB), to the ontogeny and sustenance of the BLB. Our empirical findings delineate that the maturation of the BLB in murine models is not realized until approximately two weeks post-birth, with preceding stages characterized by notable permeability. Transcriptomic analysis elucidates a marked augmentation in Mfsd2a expression within the lateral wall of the cochlea in specimens exhibiting an intact BLB. Moreover, both in vitro and in vivo assays substantiate that a diminution in Mfsd2a expression detrimentally impacts BLB permeability and structural integrity, principally via the attenuation of tight junction protein expression and the enhancement of endothelial cell transcytosis. These insights underscore the indispensable role of Mfsd2a in ensuring BLB integrity and propose it as a viable target for therapeutic interventions aimed at the amelioration of hearing loss., Competing Interests: Declaration of competing interest The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024. Published by Elsevier B.V.)

Background & Aims: Putative anion transporter-1 (PAT1, SLC26A6) plays a key role in intestinal oxalate and bicarbonate secretion. PAT1 knockout (PKO) mice exhibit hyperoxaluria and nephrolithiasis. Notably, diseases such as inflammatory bowel disease are also associated with higher risk of hyperoxaluria and nephrolithiasis. However, the potential role of PAT1 deficiency in gut-barrier integrity and susceptibility to colitis is currently elusive., Methods: Age-matched PKO and wild-type littermates were administered 3.5% dextran sulfate sodium in drinking water for 6 days. Ileum and colon of control and treated mice were harvested. Messenger RNA and protein expression of tight junction proteins were determined by reverse transcription polymerase chain reaction and western blotting. Severity of inflammation was assessed by measuring diarrheal phenotype, cytokine expression, and hematoxylin and eosin staining. Gut microbiome and associated metabolome were analyzed by 16S ribosomal RNA sequencing and mass spectrometry, respectively., Results: PKO mice exhibited significantly higher loss of body weight, gut permeability, colonic inflammation, and diarrhea in response to dextran sulfate sodium treatment. In addition, PKO mice showed microbial dysbiosis and significantly reduced levels of butyrate and butyrate-producing microbes compared with controls. Co-housing wild-type and PKO mice for 4 weeks resulted in PKO-like signatures on the expression of tight junction proteins in the colons of wild-type mice., Conclusions: Our data demonstrate that loss of PAT1 disrupts gut microbiome and related metabolites, decreases gut-barrier integrity, and increases host susceptibility to intestinal inflammation. These findings, thus, highlight a novel role of the oxalate transporter PAT1 in promoting gut-barrier integrity, and its deficiency appears to contribute to the pathogenesis of inflammatory bowel diseases., (Published by Elsevier Inc.)

The study examined the impact of adding oregano extract and/or rosemary to broiler diets to counteract the growth inhibition caused by heat stress (HS). It also investigated the effects on the activity of digestive enzymes, microbiological composition, and the expression of antioxidant and tight junction-related proteins. Three hundred- and fifty-day-old male broilers, were randomly assigned to 7 treatment groups, with each group comprising 5 replicates, and each replicate containing 10 chicks in a cage. The diets were: 1) a basal diet, 2) a diet supplemented with 50 mg/kg of rosemary, 3) a diet supplemented with 100 mg/kg of rosemary, 4) a diet supplemented with 50 mg/kg of oregano, 5) a diet supplemented with 100 mg/kg of oregano, 6) a combination diet containing 50 mg/kg each of rosemary and oregano, and 7) a combination diet containing 100 mg/kg each of rosemary and oregano. Dietary oregano extract enhanced the growth and feed utilization of heat-stressed birds, especially at a concentration of 50 mg/kg. Moreover, oregano extract improved jejunal protease and amylase activities. The extracts of rosemary and oregano significantly reduced IgG and IgM levels. Dietary 50 mg oregano extract significantly upregulated intestinal integrity-related genes including jejunal CLDNI, ZO-1, ZO-2, and MUC2. Dietary 50 mg oregano extract significantly downregulated hepatic NADPH oxidase 4 (NOX4) and nitric oxide synthase 2 (NOS2) expressions. Our results suggest that incorporating oregano leaf extract into the diet at a concentration of 50 mg/kg improves the growth performance of broilers exposed to heat stress. This improvement could be attributed to enhanced gut health and the modulation of genes associated with oxidative stress and tight junction proteins., Competing Interests: DISCLOSURES The authors declare no conflicts of interest, (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Ulcerative colitis (UC) is a complex, refractory inflammatory bowel disease characterized impared intestinal mucosal barrier and imbalanced M1/M2 macrophage polarization mediating its progression. Formononetin (FN), a bioactive isoflavone with established anti-inflammatory and immunomodulatory properties, shows promise in mitigating UC, yet its therapeutic and underlying mechanisms remain unclear. In this study, colitis was induced in mice by administering 2.5% (w/v) dextran sulfate sodium (DSS) solution for 7 days. Oral (25, 50, and 100 mg/kg) FN for 10 days significantly ameliorated colitis symptoms in a dose-dependent manner, by mitigating body weight loss, reducing disease activity index (DAI), colonic weight, and colonic weight index, while enhancing survival rates and colonic length. Histological analysis revealed FN remarkably suppressed inflammatory damage in colonic tissues. Furthermore, FN modulated the expression of pro- and anti-inflammatory cytokines and enhanced antioxidant capacity. Notably, FN treatment significantly enhanced the expression of tight junction (TJ) proteins (claudin-1, ZO-1, occludin) at both protein and mRNA levels in the colon tissues, suggesting improved intestinal barrier function. Crucially, FN inhibited macrophage infiltration in colonic tissues and rebalanced M1/M2 macrophage polarization. While, macrophage depletion largely abrogated FN's protective effects against colitis, indicating a crucial role for macrophages in mediating FN's therapeutic response. Overall, FN effectively alleviated colitis primarily via modulating inflammatory cytokine expression, enhancing antioxidant capacity, upregulating TJs proteins expression, and remodeling M1/M2 macrophage polarization equilibrium. These findings suggest that FN could be the next candidate to unlocking UC's treatment challenge., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Ethnopharmacological Relevance: Prinsepia utilis Royle, native to the Himalayan region, has a long history of use in traditional medicine for its heat-clearing, detoxification, anti-inflammatory, and analgesic properties. Oils extracted from P. utilis seeds are also used in cooking and cosmetics. With the increasing market demand, this extraction process generates substantial industrial biowastes. Recent studies have found many health benefits with using aqueous extracts of these biowastes, which are also rich in polysaccharides. However, there is limited research related to the reparative effects of the water extracts of P. utilis oil cakes (WEPUOC) on disruptions of the skin barrier function., Aim of the Study: This study aimed to evaluate the reparative efficacy of WEPUOC in both acute and chronic epidermal permeability barrier disruptions. Furthermore, the study sought to explore the underlying mechanisms involved in repairing the epidermal permeability barrier., Materials and Methods: Mouse models with induced epidermal disruptions, employing tape-stripping (TS) and acetone wiping (AC) methods, were used. The subsequent application of WEPUOC (100 mg/mL) was evaluated through various assessments, with a focus on the upregulation of mRNA and protein expression of Corneocyte Envelope (CE) related proteins, lipid synthase-associated proteins, and tight junction proteins., Results: The polysaccharide was the major phytochemicals of WEPUOC and its content was determined as 32.2% by the anthranone-sulfuric acid colorimetric method. WEPUOC significantly reduced transepidermal water loss (TEWL) and improved the damaged epidermal barrier in the model group. Mechanistically, these effects were associated with heightened expression levels of key proteins such as FLG (filaggrin), INV (involucrin), LOR (loricrin), SPT, FASN, HMGCR, Claudins-1, Claudins-5, and ZO-1., Conclusions: WEPUOC, obtained from the oil cakes of P. utilis, is rich in polysaccharides and exhibits pronounced efficacy in repairing disrupted epidermal barriers through increased expression of critical proteins involved in barrier integrity. Our findings underscore the potential of P. utilis wastes in developing natural cosmetic prototypes for the treatment of diseases characterized by damaged skin barriers, including atopic dermatitis and psoriasis., Competing Interests: Declaration of competing interest This paper has not been published elsewhere in whole or in part. All authors have read and approved the content, and agree to submit it for consideration for publication in your journal. There are no ethical/legal conflicts involved in the article., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Recent studies point to intestinal permeability as an important factor in the establishment and development of rheumatoid arthritis (RA). Tight junctions (TJs) play a major role in intestinal homeostasis. The alteration of this homeostasis is related to RA. Furthermore, RA patients present dysbiosis and a lower microbiota diversity compared to healthy individuals. A cross-sectional study including RA patients and sex- and age-matched healthy controls was performed. The quantification of TJ proteins was carried out by ELISA. Gut microbiota was evaluated by NGS platform Ion Torrent S. The inflammatory variables included were DAS28, CRP, inflammatory cytokines (IL-6, IL-1, TNF-α) and oxidised LDL. Claudin-1 levels showed significant differences between groups. Results evidenced a correlation between claudin-1 values and age ( r : -0.293; p < 0.05), IL6 ( r : -0.290; p < 0.05) and CRP ( r : -0.327; p < 0.05), and between zonulin values and both age ( r : 0.267; p < 0.05) and TNFα ( r : 0.266; p < 0.05). Moreover, claudin-1 and CRP levels are related in RA patients ( β : -0.619; p : 0.045), and in patients with high inflammatory activity, the abundance of the genus Veillonella is positively associated with claudin-1 levels ( β : 39.000; p : 0.004).

Changes to blood-brain barrier structure and function may affect the delivery of drugs into the brain. It is worthwhile to exploring more study on how the blood-brain barrier changes in structure and function and how that affects drug transport in high-altitude hypoxic environment. The DIA high-throughput sequencing technique indicate that the rats blood-brain barrier has been identified to have 7252 proteins overall and 8 tight junction proteins, among which Claudin-7 was a plateau-specific tight junction protein under high-altitude hypoxia, and based on the interaction network study, 2421 proteins are found to interact with one another, with ZO-1 being the primary target. The results of the projected gene function analysis demonstrated that changes in tight junction proteins are related to the control of TRP channels by inflammatory mediators, the wnt signaling pathway, the ABC transporter system, and drug metabolism-CYP450 enzyme regulation. Additionally, the electron microscopy, the Evans blue combination with confocal laser scanning microscopy, and the Western Blot and RT-qPCR revealed that high-altitude hypoxic environment induces blood-brain barrier tight junctions to open, blood-brain barrier permeability increases, ZO-1, Occludin, Claudin-5 protein and mRNA expression decreased. Our research implies that structural and functional alterations in the blood-brain barrier induced by high altitude hypoxia may impact drug transport inside the central nervous system, and that drug transporters and drug-metabolizing enzymes may be key players in this process., (© 2024. The Author(s), under exclusive licence to American Association of Pharmaceutical Scientists.)

Low temperature is a common stress source for the poultry industry in the north of China. However, the low energy consuming and economical way to reduce the negative effects from cold stress is still limited. Therefore, the aim of this study was to investigate the effect of rutin on intestinal barrier in mice under low temperature. The cold stress model was established at 4°C for 3 h each day and the experiment lasted for 21 days. Forty Balb/c mice were randomly divided into four treatments: CON, normal temperature with the basal diet; RUT, normal temperature with the basal diet +150 mg/kg body weight (BW) of rutin; CS, mice under cold stress with basal diet; CR, 150 mg/kg of BW rutin under cold stress. Rutin supplementation significantly increased the ileum villus-to-crypt ratio compared with these non-supplemented treatments. Rutin attenuated the hypothermia induced morphological damage in the ileum. In addition, rutin improved the antioxidant capacity of mice under cold stress. Rutin supplementation significantly increased the trypsin activity and inhibited the lipase in cold stressed mice. Rutin supplementation significantly inhibited the production of inflammatory factors induced by cold stress. Rutin induced the inhibition of TLR4 and NF-кB, thereby reducing the expression of inflammation-related genes. In addition, rutin improved the reduction of the intestinal claudin-1 and occludin expression in those mice in the cold stress (P < .05) and improved the intestinal ZO-1 expression in cold stressed mice. Finally, rutin alleviated the dysregulation of intestinal microflora in the mice under cold stress., Competing Interests: Declaration of competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have influenced the work reported in this paper, and have agreed to publish it., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Transmembrane proteins play key roles in the development of lung cancer. The family with sequence similarity 189 member A2 (FAM189A2) gene encodes a transmembrane structural protein, yet its involvement in lung adenocarcinoma remains largely unexplored. This study elucidated its role in lung adenocarcinoma and its possible molecular mechanism. Our findings revealed diminished expression levels of FAM189A2 in LUAD tissues. Additionally, the activity of LUAD cells was significantly inhibited by overexpression of FAM189A2. Following FAM189A2 overexpression, the expression of OCLN and TJP2 was upregulated in LUAD cells, while CXCR4 expression experiences a notable decrease. Moreover, the coimmunoprecipitation experiment confirmed the direct interaction between FAM189A2 and CXCR4. The infiltration levels of T cells (CD4+ memory resting, CD8+, regulatory), NK cells, B memory cells, endothelial cells and cancer-associated fibroblasts were significantly correlated with FAM189A2 expression. These results indicate FAM189A2 may act as a tumour suppressor in LUAD through tight junction protein (TJP) and CXCR4 regulation. Moreover, FAM189A2 is significantly correlated with the immune microenvironment of LUAD, which may be involved in prognosis and immunotherapeutic efficacy., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Biomolecular condensates enable cell compartmentalization by acting as membraneless organelles 1 . How cells control the interactions of condensates with other cellular structures such as membranes to drive morphological transitions remains poorly understood. We discovered that formation of a tight-junction belt, which is essential for sealing epithelial tissues, is driven by a wetting phenomenon that promotes the growth of a condensed ZO-1 layer 2 around the apical membrane interface. Using temporal proximity proteomics in combination with imaging and thermodynamic theory, we found that the polarity protein PATJ mediates a transition of ZO-1 into a condensed surface layer that elongates around the apical interface. In line with the experimental observations, our theory of condensate growth shows that the speed of elongation depends on the binding affinity of ZO-1 to the apical interface and is constant. Here, using PATJ mutations, we show that ZO-1 interface binding is necessary and sufficient for tight-junction belt formation. Our results demonstrate how cells exploit the collective biophysical properties of protein condensates at membrane interfaces to shape mesoscale structures., (© 2024. The Author(s).)

Obstructive jaundice (OJ) can cause multiple pathophysiological consequences including intestinal barrier dysfunction. Omega-3 has been indicated to have a promising therapeutic effect on OJ. This study aimed to further investigate the functions of omega-3 on OJ-induced intestinal injury. A rat OJ model was established by bile duct ligation with or without omega-3 administration. ELISA was utilized for measuring serum levels of inflammatory cytokines. Hematoxylin-eosin staining and TUNEL staining were employed for detecting the morphological changes and cell apoptosis in rat intestine. Western blotting was utilized for evaluating expression of tight junction proteins in the intestinal tissues. Omgea-3 offset the reduction in body weight of OJ rats. Omega-3 alleviated inflammatory response, pathological damages and cell apoptosis in the intestine of OJ rats. Additionally, omega-3 enhanced levels of tight junction proteins in the intestinal tissues of OJ rats. Omega-3 ameliorates OJ-triggered impairment of intestinal barrier function in rats., (© 2023. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Objectives: This study aimed to explore the protective mechanism of chitosan oligosaccharide (COS) against lipopolysaccharide (LPS)-induced inflammatory responses in IEC-6 cells and dextran sodium sulfate (DSS)-induced colitis in mice., Methods: The cell inflammation model was constructed by LPS in vitro and enteritis model by DSS in vivo., Results: Following LPS exposure, IEC-6 cell proliferation significantly decreased, epithelial cell integrity was compromised, and TNF-α and IL-1β levels were increased. However, COS pretreatment reversed these changes. In vivo, DSS-treated mice exhibited evident pathological alterations, including heightened inflammatory levels and significantly decreased expression of tight junction proteins and critical proteins in the Mitogen activated proteins kinase signaling pathway. Nevertheless, COS administration notably reduced inflammatory levels and increased the expression of tight junction proteins and key proteins in the Mitogen activated proteins kinase signaling pathway., Conclusions: Our findings suggest that COS safeguards gut barrier integrity by upregulating tight junction proteins through the ERK1/2 signaling pathway. Therefore, COS has emerged as a promising candidate for novel drug interventions against inflammatory bowel disease., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Xianghong Ju has patent pending to Xianghong Ju. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

The objective of this study was to determine the effects of dietary crude protein (CP) levels on intestinal antioxidant status, tight junction proteins expression, and amino acids transporters levels in squabs. A total of 180 pairs of White King parent pigeons approximately 10 mo old were randomly assigned to 5 groups with 6 replications of 6 pairs of parental pigeons each, and were fed with 14, 15, 16, 17, and 18% CP diets for 46 d, respectively. Dietary increasing CP levels increased final body weight (linear and quadratic, P < 0.05), serum urea nitrogen (linear, P<0.05) and triglyceride levels (quadratic, P < 0.05), and reduced kidney relative weight (quadratic, P < 0.05) in squabs. Final body weight of squabs in the 18% CP diet group was higher than that of the 14, 15, and 16% CP diet groups (P < 0.05) but was similar to that of the 17% CP diet group (P > 0.05). Increasing dietary CP levels reduced intestinal malondialdehyde contents (linear and quadratic, P < 0.05) and jejunal total superoxide dismutase (T-SOD) activity (linear, P < 0.05), and enhanced (linear and quadratic, P<0.05) ileal catalase and T-SOD activities in squabs, and these effects were more prominent in the 17% CP diet group. Graded CP levels up-regulated the mRNA expression of intestinal zonula occludens 1 (linear, P < 0.05), solute carrier family 7 members 9 (linear, P < 0.05) and claudin 1 (CLDN1, linear and quadratic, P < 0.05), ileal CLDN3 and solute carrier family 6 members 14 (linear, P < 0.05) but lowered jejunal solute carrier family 6 member 14 (quadratic, P<0.05) mRNA expression in squabs. The effects of dietary CP levels on intestinal tight junction proteins expression were more apparent when its supplemental levels were 18%. These results suggested that increasing parental dietary CP levels ranged from 14 to 18% during breeding period improved growth and intestinal function of squabs, with its recommended level being 17%., Competing Interests: DISCLOSURES The authors declare that they have no conflict of interest., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

1. An experiment was conducted to determine differences in the expression of genes encoding intestinal barrier proteins between fast, medium and slow-growing chickens. Chicken breeds Athens Canadian Random Bred (ACRB), Longenecker's Heritage (LHR), RedBro, Hubbard H1 (HH1), Cobb500 and Ross708 were raised from hatch for 35 d.2. Ileal samples were collected at embryonic day E19 (-2 days post-hatch), hatch and d 7, 14, 21, 28 and 35 post-hatch to assess the expression of genes encoding tight junction proteins (claudins, CLDN; occludin, OCLN; zonula occludens, ZO; and junctional adhesion molecules, JAM), mucin (Muc2), immunoglobulin A (IgA), polymeric immunoglobulin receptor (pIgR) and fatty acid binding protein (FABP2).3. Expression of CLDN-1 was increased ( p  < 0.0001) in LHR compared to Cobb500 while CLDN-5 was increased ( p  < 0.0001) in ACRB, HH1, RedBro and Ross708 compared to LHR as well as in ACRB compared to Cob500. Occludin was upregulated ( p  = 0.01) in ACRB and LHR compared to Ross708 at d 14 post-hatch. Expression of ZO-1 was upregulated ( p  = 0.001) in LHR compared to Ross708, HH1 and Cobb500. Tight junction genes, except CLDN-4, JAM-2 and JAM-3 were downregulated ( p < 0.0001) at hatch and d 7 post-hatch. Expression of Muc2 was increased ( p  < 0.0001) in LHR compared to RedBro and from -2 d to d 7 post-hatch.4. Immunoglobulin A was increased ( p  = 0.001) in LHR compared to Ross708 and HH1 at -2 d post-hatch and in LHR compared to ACRB, Cobb500 and Ross708 at hatch. In addition, IgA expression was increased in all breeds at d 14 post-hatch while pIgR was upregulated ( p  = 0.02) in Cobb500 and Ross708 compared to ACRB, HH1, LHR and RedBro at hatch.5. The gene expression patterns suggest that selection for growth may have not induced changes in junctional complexes and immune defence genes. However, the results confirmed that the expression of these genes is age dependent.

Background: Ulcerative colitis (UC) is a prolonged inflammatory disease of the gastrointestinal tract. Current therapeutic options remain limited, underscoring the imperative to explore novel therapeutic strategies. Narirutin (NR), a flavonoid naturally present in citrus fruits, exhibits excellent anti-inflammatory effects in vitro, yet its in vivo efficacy, especially in UC, remains underexplored., Objective: This work examined the effect of NR on dextrose sodium sulfate (DSS)-induced UC in mice in vivo, with a specific focus on the role of gut flora in it., Methods: The effects of NR (10, 20, and 40 mg/kg) on DSS-induced UC in mice were investigated by monitoring changes in body weight, disease activity index (DAI) scores, colon length, and histological damage. Colonic levels of pro-inflammatory mediators, tight junction (TJ) proteins, and inflammation-related signaling pathway proteins were analyzed via enzyme-linked immunosorbent assay, western blot, and immunofluorescence. The role of gut microbiota in NR against colitis was analyzed through 16S rRNA sequencing, flora clearance assays, and fecal microbiota transplantation (FMT) assays., Results: NR administration suppressed DSS-induced colitis as reflected in a decrease in body weight loss, DAI score, colon length shortening, and histological score. Furthermore, NR administration preserved the integrity of the DSS-induced intestinal barrier by inhibiting the reduction of TJ proteins (claudin3, occludin, and zonula occludens-1). Moreover, NR administration markedly repressed the activation of the toll-like receptor 4-mitogen-activated protein kinase/nuclear factor-κB pathway and reduced the amount of pro-inflammatory mediators in the colon. Importantly, the results of 16S rRNA sequencing showed that the intestinal flora of mice with colitis exhibited richer microbial diversity following NR administration, with elevated abundance of Lactobacillaceae (Lactobacillus) and decreased abundance of Bacteroidaceae (Bacteroides) and Shigella. In addition, the anti-colitis effect of NR almost disappeared after gut flora clearance. Further FMT assay also validated this gut flora-dependent protective mechanism of NR., Conclusion: Our findings suggest that NR is a prospective natural compound for the management of UC by modulating intestinal flora., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier GmbH. All rights reserved.)

Background: HIV-associated neurocognitive disorders (HAND) still affects persons with HIV (PWH) and their pathogenesis is not completely understood. We aimed to explore the association between plasma and cerebrospinal fluid (CSF) markers of blood-brain barrier (BBB) impairment and HAND in untreated PWH., Design: Cross-sectional study., Methods: We enrolled untreated PWH, who underwent blood examinations and lumbar puncture to measure inflammation (IL-15, TNF-α), BBB damage (zonulin and tight junction proteins, tight junction proteins: occludin, claudin-5) and endothelial adhesion molecules (VCAM-1, ICAM-1). A comprehensive neurocognitive battery was used to diagnose HAND (Frascati criteria)., Results: Twenty-one patients (21/78, 26.9%) patients presented HAND (100% ANI). HAND patients displayed more frequently non-CNS AIDS-defining conditions, lower nadir CD4 + T cells and increased CD4 + T-cell exhaustion (lower CD4 + CD127 + and CD4 + CD45RA + T-cell percentages), in comparison to individuals without cognitive impairment. Furthermore, HAND was characterized by higher plasma inflammation (IL-15) but lower CSF levels of biomarkers of BBB impairment (zonulin and occludin). The association between BBB damage with HAND was confirmed by fitting a multivariable logistic regression. CSF/plasma endothelial adhesion molecules were not associated with HAND but with a poor performance in different cognitive domains., Conclusion: By showing heightened inflammation and BBB impairment, our study suggests loss of BBB integrity as a possible factor contributing to the development of HAND in untreated PWH., (Copyright © 2024 The Author(s). Published by Wolters Kluwer Health, Inc.)

Climate change is an increasing concern of stakeholders worldwide. The intestine is severely impacted by the heat stress. This study aimed to investigate the alleviating effects of methionine on the intestinal damage induced by heat stress in mice. The mice were divided into four groups: control group (C), methionine deficiency group (MD), methionine + heat stress group (MH), and methionine deficiency + heat stress group (MDH). Histopathological techniques, PAS-Alcian blue staining, immunohistochemistry method, biochemical quantification method, ELISA, and micro method were used to study the changes in the intestinal mucosal morphology, the number of goblet cells, the expression of tight junction proteins, the peroxide product contents and antioxidant enzyme activities, the intestinal mucosal damage, the content of immunoglobulins and HSP70, the activity of Na + /K + -ATPase. The results showed that methionine can improve intestinal mucosal morphology (increase the villi height, V/C value, and muscle layer thickness, decrease crypt depth), increase the expression of tight junction proteins (Claudin-1, Occludin, ZO-1) and the content of DAO, decrease the content of intestinal mucosa damage markers (ET, FABP2) and peroxidation products (MDA), increase the activity of antioxidant enzymes (GR, GSH-Px, SOD), the number of goblet cells, the contents of immunoglobulins (sIgA, IgA, IgG, IgM) and stress protein (HSP70), and the activity of Na + /K + -ATPase. It is suggested that methionine can alleviate intestinal damage in heat-stressed mice., Competing Interests: Declaration of competing interest The authors report no conflict of interest., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Hypoxia plays an important role in the pathological process of bladder outlet obstruction. Previous research has mostly focused on the dysfunction of bladder smooth muscle cells, which are directly related to bladder contraction. This study delves into the barrier function changes of the urothelial cells under exposure to hypoxia. Results indicated that after a 5-day culture, SV-HUC-1 formed a monolayer and/or bilayer of cell sheets, with tight junction formation, but no asymmetrical unit membrane was observed. qPCR and western blotting revealed the expression of TJ-associated proteins (occludin, claudin1 and ZO-1) was significantly decreased in the hypoxia group in a time-dependent manner. No expression changes were observed in uroplakins. When compared to normoxic groups, immunofluorescent staining revealed a reduction in the expression of TJ-associated proteins in the hypoxia group. Transepithelial electrical resistance (TEER) revealed a statistically significant decrease in resistance in the hypoxia group. Fluorescein isothiocyanate-conjugated dextran assay was inversely proportional to the results of TEER. Taken together, hypoxia down-regulates the expression of TJ-associated proteins and breaks tight junctions, thus impairing the barrier function in human urothelial cells., (© 2024 The Author(s). Journal of Cellular and Molecular Medicine published by Foundation for Cellular and Molecular Medicine and John Wiley & Sons Ltd.)

Background: Epilepsy in dogs and humans is associated with blood-brain barrier (BBB) dysfunction (BBBD), which may involve dysfunction of tight junction (TJ) proteins, matrix metalloproteases, and astrocytes. Imaging techniques to assess BBB integrity, to identify potential treatment strategies, have not yet been evaluated in veterinary medicine., Hypothesis: Some dogs with idiopathic epilepsy (IE) will exhibit BBBD. Identifying BBBD may improve antiepileptic treatment in the future., Animals: Twenty-seven dogs with IE and 10 healthy controls., Methods: Retrospective, prospective cohort study. Blood-brain barrier permeability (BBBP) scores were calculated for the whole brain and piriform lobe of all dogs by using dynamic contrast enhancement (DCE) magnetic resonance imaging (MRI) and subtraction enhancement analysis (SEA). Matrix metalloproteinase-9 (MMP9) activity in serum and cerebrospinal fluid (CSF) was measured and its expression in the piriform lobe was examined using immunofluorescent staining. Gene expression of TJ proteins and astrocytic transporters was analyzed in the piriform lobe., Results: The DCE-MRI analysis of the piriform lobe identified higher BBBP score in the IE group when compared with controls (34.5% vs 26.5%; P = .02). Activity and expression of MMP9 were increased in the serum, CSF, and piriform lobe of IE dogs as compared with controls. Gene expression of Kir4.1 and claudin-5 in the piriform lobe of IE dogs was significantly lower than in control dogs., Conclusions and Clinical Importance: Our findings demonstrate BBBD in dogs with IE and were supported by increased MMP9 activity and downregulation of astrocytic potassium channels and some TJ proteins. Blood brain barrier dysfunction may be a novel antiepileptic therapy target., (© 2024 The Authors. Journal of Veterinary Internal Medicine published by Wiley Periodicals LLC on behalf of American College of Veterinary Internal Medicine.)

Ulcerative colitis (UC) is an immune-mediated inflammatory disease that can lead to persistent damage and even cancer without any intervention. Conventional treatments can alleviate UC symptoms but are costly and cause various side effects. Tauroursodeoxycholic acid (TUDCA), a secondary bile acid derivative, possesses anti-inflammatory and cytoprotective properties for various diseases, but its potential therapeutic benefits in UC have not been fully explored. Mice were subjected to colitis induction using 3% dextran sulfate sodium (DSS). The therapeutic effect of TUDCA was evaluated by body weight loss, disease activity index (DAI), colon length, and spleen weight ratio. Tissue pathology was assessed using H&E staining, while the levels of pro-inflammatory and anti-inflammatory cytokines in colonic tissue were quantified via ELISA. Tight junction proteins were detected by immunoblotting and intestinal permeability was assessed using fluorescein isothiocyanate (FITC)-dextran. Moreover, the gut microbiota was profiled using high-throughput sequencing of the 16S rDNA gene. TUDCA alleviated the colitis in mice, involving reduced DAI, attenuated colon and spleen enlargement, ameliorated histopathological lesions, and normalized levels of pro-inflammatory and anti-inflammatory cytokines. Furthermore, TUDCA treatment inhibited the downregulation of intestinal barrier proteins, including zonula occludens-1 and occludin, thus reducing intestinal permeability. The analysis of gut microbiota suggested that TUDCA modulated the dysbiosis in mice with colitis, especially for the remarkable rise in Akkermansia TUDCA exerted a therapeutic efficacy in DSS-induced colitis by reducing intestinal inflammation, protecting intestinal barrier integrity, and restoring gut microbiota balance. SIGNIFICANCE STATEMENT: This study demonstrates the potential therapeutic benefits of Tauroursodeoxycholic acid (TUDCA) in ulcerative colitis. TUDCA effectively alleviated colitis symptoms in mice, including reducing inflammation, restoring intestinal barrier integrity and the dysbiosis of gut microbiota. This work highlights the promising role of TUDCA as a potentially alternative treatment, offering new insights into managing this debilitating condition., (Copyright © 2024 by The Author(s).)

Bacteriocins have the potential to effectively improve food-borne infections or gastrointestinal diseases and hold promise as viable alternatives to antibiotics. This study aimed to explore the antibacterial activity of three bacteriocins (nisin, enterocin Gr17, and plantaricin RX-8) and their ability to attenuate intestinal barrier dysfunction and inflammatory responses induced by Listeria monocytogenes, respectively. Bacteriocins have shown excellent antibacterial activity against L. monocytogenes without causing any cytotoxicity. Bacteriocins inhibited the adhesion and invasion of L. monocytogenes on Caco-2 cells, lactate dehydrogenase (LDH), trans-epithelial electrical resistance (TEER), and cell migration showed that bacteriocin improved the permeability of Caco-2 cells. These results were attributed to the promotion of tight junction proteins (TJP) assembly, specifically zonula occludens-1 (ZO-1), occludin, and claudin-1. Furthermore, bacteriocins could alleviate inflammation by inhibiting the mitogen-activated protein kinase (MAPK) and nuclear factor kappa B (NF-κB) pathways and reducing the secretion of interleukin-6 (IL-6), interleukin-1 β (IL-1β) and tumor necrosis factor α (TNF-α). Among three bacteriocins, plantaricin RX-8 showed the best antibacterial activity against L. monocytogenes and the most pronounced protective effect on the intestinal barrier due to its unique structure. Based on our findings, we hypothesized that bacteriocins may inhibit the adhesion and invasion of L. monocytogenes by competing adhesion sites. Moreover, they may further enhance intestinal barrier function by inhibiting the expression of L. monocytogenes virulence factors, increasing the expression of TJP and decreasing the secretion of inflammatory factors. Therefore, bacteriocins will hopefully be an effective alternative to antibiotics, and this study provides valuable insights into food safety concerns. KEY POINTS: • Bacteriocins show excellent antibacterial activity against L. monocytogenes • Bacteriocins improve intestinal barrier damage and inflammatory response • Plantaricin RX-8 has the best protective effect on Caco-2 cells damage., (© 2024. The Author(s).)

The aim of this study was to evaluate the preventive role and underlying mechanisms of fucoxanthin (Fx) on lipopolysaccharide (LPS)-induced intestinal barrier injury in mice. Our results demonstrated that the oral administration of Fx (50 and 200 mg per kg body weight per day) for consecutive 7 days significantly alleviated the severity of LPS-induced intestinal barrier injury in mice, as evidenced by attenuating body weight loss, improving intestinal permeability, and ameliorating intestinal morphological damage such as reduction in the ratio of the villus length to the crypt depth ( V / C ), intestinal epithelium distortion, goblet cell depletion, and low mucin 2 (MUC2) expression. Fx also significantly mitigated LPS-induced excessive apoptosis of intestinal epithelial cells (IECs) and curbed the decrease of tight junction proteins including claudin-1, occludin, and zonula occludens-1 in the ileum and colon. Additionally, Fx effectively alleviated LPS-induced extensive infiltration of macrophages and neutrophils into the intestinal mucosa, the overproduction of pro-inflammatory cytokines such as tumor necrosis factor-alpha (TNF-α), interleukin 1beta (IL-1β) and IL-6, and gasdermin D (GSDMD)-mediated pyroptosis of IECs. The underlying mechanisms might be associated with inhibiting the activation of nuclear factor-kappa B (NF-κB), mitogen-activated protein kinases (MAPKs) and nod-like receptor family pyrin domain-containing 3 (NLRP3) inflammasome signaling pathways. Moreover, Fx also notably restrained intestinal reactive oxygen species (ROS), malondialdehyde and protein carbonylation levels in LPS-treated mice, and it might be mediated by activating the nuclear factor-erythroid 2 related factor 2 (Nrf2) signaling pathway. Overall, these findings indicated that Fx might be developed as a potential effective dietary supplement to prevent intestinal barrier injury.

Bioactive oligopeptides have gained increasing attention due to their diverse physiological functions, and these can be transported into the vasculature via transcellular and paracellular pathways. Among these, paracellular transport through the intercellular space is a passive diffusion process without energy consumption. It is currently the most frequently reported absorption route for food-derived bioactive oligopeptides. Previous work has demonstrated that paracellular pathways are mainly controlled by tight junctions, but the mechanism by which they regulate paracellular absorption of bioactive oligopeptides remains unclear. In this review, we summarized the composition of paracellular pathways across the intercellular space and elaborated on the paracellular transport mechanism of bioactive oligopeptides in terms of the interaction between oligopeptides and tight junction proteins, the protein expression level of tight junctions, the signaling pathways regulating intestinal permeability, and the properties of oligopeptides themselves. These findings contribute to a more profound understanding of the paracellular absorption of bioactive oligopeptides.

Neutrophils (polymorphonuclear leukocytes, PMNs) comprise a major component of the immune cell infiltrate during acute mucosal inflammation and have an important role in molding the inflammatory tissue environment. While PMNs are essential to clearance of invading microbes, the major PMN antimicrobial enzyme myeloperoxidase (MPO) can also promote bystander tissue damage. We hypothesized that blocking MPO would attenuate acute colitis and prevent the development of chronic colitis by limiting bystander tissue damage. Using the acute and chronic dextran sodium sulfate model of murine colitis, we demonstrated that MPO-deficient mice experienced less inflammation and more rapidly resolved colitis relative to wild-type controls. Mechanistic studies demonstrated that activated MPO disrupted intestinal epithelial barrier function through the dysregulation of the epithelial tight junction proteins. Our findings revealed that activated MPO chlorinates tyrosine within several tight junction proteins, thereby promoting tight junction mislocalization and dysfunction. These observations in cell models and in murine colitis were validated in human intestinal biopsies from individuals with ulcerative colitis and revealed a strong correlation between disease severity (Mayo score) and tissue chlorinated tyrosine levels. In summary, these findings implicate MPO as a viable therapeutic target to limit bystander tissue damage and preserve mucosal barrier function during inflammation.

The management of gastrointestinal disease in animals represents a significant challenge in veterinary and zootechnic practice. Traditionally, acute symptoms have been treated with antibiotics and high doses of zinc oxide (ZnO). However, concerns have been raised regarding the potential for microbial resistance and ecological detriment due to the excessive application of this compound. These concerns highlight the urgency of minimizing the use of ZnO and exploring sustainable nutritional solutions. Hydrolysable tannins (HTs), which are known for their role in traditional medicine for acute gastrointestinal issues, have emerged as a promising alternative. This study examined the combined effect of food-grade HTs and subtherapeutic ZnO concentration on relevant biological functions of Caco-2 cells, a widely used model of the intestinal epithelial barrier. We found that, when used together, ZnO and HTs (ZnO/HTs) enhanced tissue repair and improved epithelial barrier function, normalizing the expression and functional organization of tight junction proteins. Finally, the ZnO/HTs combination strengthened enterocytes' defense against oxidative stress induced by inflammation stimuli. In conclusion, combining ZnO and HTs may offer a suitable and practical approach for decreasing ZnO levels in veterinary nutritional applications.

Microplastics, which are tiny plastic particles less than 5 mm in diameter, are widely present in the environment, have become a serious threat to aquatic life and human health, potentially causing ecosystem disorders and health problems. The present study aimed to investigate the effects of microplastics, specifically microplastics-polystyrene (MPs-PS), on the structural integrity, gene expression related to tight junctions, and gut microbiota in mice. A total of 24 Kunming mice aged 30 days were randomly assigned into four groups: control male (CM), control female (CF), PS-exposed male (PSM), and PS-exposed female (PSF)(n = 6). There were significant differences in villus height, width, intestinal surface area, and villus height to crypt depth ratio (V/C) between the PS group and the control group(C) (p <0.05). Gene expression analysis demonstrated the downregulation of Claudin-1, Claudin-2, Claudin-15, and Occludin, in both duodenum and jejunum of the PS group (p < 0.05). Analysis of microbial species using 16S rRNA sequencing indicated decreased diversity in the PSF group, as well as reduced diversity in the PSM group at various taxonomic levels. Beta diversity analysis showed a significant difference in gut microbiota distribution between the PS-exposed and C groups (R2 = 0.113, p<0.01), with this difference being more pronounced among females exposed to MPs-PS. KEGG analysis revealed enrichment of differential microbiota mainly involved in seven signaling pathways, such as nucleotide metabolism(p<0.05). The relative abundance ratio of transcriptional pathways was significantly increased for the PSF group (p<0.01), while excretory system pathways were for PSM group(p<0.05). Overall findings suggest that MPs-PS exhibit a notable sex-dependent impact on mouse gut microbiota, with a stronger effect observed among females; reduced expression of tight junction genes may be associated with dysbiosis, particularly elevated levels of Prevotellaceae., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2024 Su et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

The intestinal mucosal barrier is of great importance for maintaining the stability of the internal environment, which is closely related to the occurrence and development of intestinal inflammation. Octreotide (OCT) has potential applicable clinical value for treating intestinal injury according to previous studies, but the underlying molecular mechanisms have remained elusive. This article is based on a cell model of inflammation induced by lipopolysaccharide (LPS), aiming to explore the effects of OCT in protecting intestinal mucosal barrier function. A Cell Counting Kit‑8 assay was used to determine cell viability and evaluate the effectiveness of OCT. Gene silencing technology was used to reveal the mediated effect of somatostatin receptor 2 (SSTR2). The changes in intestinal permeability were detected through trans‑epithelial electrical resistance and fluorescein isothiocyanate‑dextran 4 experiments, and the alterations in tight junction proteins were detected using immunoblotting and reverse transcription fluorescence‑quantitative PCR technology. Autophagosomes were observed by electron microscopy and the dynamic changes of the autophagy process were characterized by light chain (LC)3‑II/LC3‑I conversion and autophagic flow. The results indicated that SSTR2‑dependent OCT can prevent the decrease in cell activity. After LPS treatment, the permeability of monolayer cells decreased and intercellular tight junctions were disrupted, resulting in a decrease in tight junction protein zona occludens 1 in cells. The level of autophagy‑related protein LC3 was altered to varying degrees at different times. These abnormal changes gradually returned to normal levels after the combined application of LPS and SSTR2‑dependent OCT, confirming the role of OCT in protecting intestinal barrier function. These experimental results suggest that OCT maintains basal autophagy and cell activity mediated by SSTR2 in intestinal epithelial cells, thereby preventing the intestinal barrier dysfunction in inflammation injury.