Search Results (916)

Bacillus velezensis-based probiotics are increasingly recognized for their potential to enhance intestinal health in companion animals, yet their mechanisms of action in canine epithelial systems remain incompletely defined. This study aimed to evaluate whether a live Bacillus velezensis probiotic consortia (BC) modulates epithelial barrier integrity, immune signaling, apoptosis-renewal pathways, and metabolic activity in canine-relevant intestinal and macrophage cell models. MCA-B1 proximal gastrointestinal epithelial cells and DH82 macrophage-like cells were exposed to BC cultures, followed by quantification of tight-junction expression, permeability (FITC-Dextran), cytokine responses, phagocytic activity, apoptosis-related markers, and metabolomic profiles. BC treatment significantly strengthened the epithelial barrier, inducing a marked upregulation of Claudin 1 (CLDN1) (11.3 fold), CLDN4 (2.4 fold), Occludin (OCLN, 1.7 fold), and increasing key proteins including ZO-2 and cingulin while reducing LPS-induced FITC-Dextran permeability to 94.5%. BC concurrently modulated innate immune signaling, increasing MyD88 (33.2%), IL-8 (14.6 fold), IL-18 (2.6 fold), and IFNB1 protein levels, while enhancing anti-inflammatory regulation, including a robust rise in DH82-derived IL-10. Apoptosis-renewal markers shifted toward physiological turnover, with increased BCL2 (1.9 fold) and reduced BAK1. Metabolomic profiling of BC activity revealed elevated AMP, abundant Peptide Transporter 1 (PEPT1)-transportable peptides, increased γ-glutamyl metabolites, and lower Glutathione disulfide (GSSG), consistent with AMPK-linked tight-junction assembly and glutathione-supported redox buffering. Together, these data indicate that Bacillus velezensis-derived metabolites positively influence barrier-related, immunological, and metabolic responses in a canine proximal intestinal epithelial system and modulate functional responses in macrophage-like cells. These in vitro findings contribute to the mechanistic understanding of host cellular responses to Bacillus-associated metabolites. Full article

Background: Intestinal acute radiation syndrome (IARS) represents a life-threatening component of acute radiation syndrome with limited effective countermeasures. Understanding molecular determinants governing intestinal epithelial resilience to ionizing radiation is critical for developing radiation toxicity mitigation strategies. Objectives: This study investigates the role of PIKfyve, a phosphoinositide kinase essential for endolysosomal homeostasis, in modulating radiation-induced intestinal toxicity. Methods: We utilized an inducible intestinal epithelial-specific PIKfyve-knockout mouse model (PIKfyve cKO) subjected to 10 Gy abdominal irradiation. Intestinal toxicity was assessed through histopathology, barrier permeability (FD4 assay), apoptosis markers, and transcriptomic profiling. Small intestinal organoids were employed for mechanistic validation. Results: PIKfyve deletion alone did not perturb normal gut architecture but precipitated severe post-irradiation toxicity, including villous atrophy, crypt hypoplasia, and massive crypt-cell apoptosis. Barrier dysfunction was evidenced by elevated serum FD4 and heightened systemic pro-inflammatory cytokines, culminating in markedly increased mortality. Transcriptomic analysis revealed potentiated DNA-damage signaling and amplified inflammatory cascades in PIKfyve-deficient intestines. Conclusions: These findings identify PIKfyve as a critical guardian of intestinal epithelial integrity against radiation toxicity. Given emerging PIKfyve inhibitors in cancer therapy, our results raise important safety considerations for clinical radiotherapy and position PIKfyve as a potential target for radiation toxicity mitigation. Full article

Background/Objectives: Aging is characterized by progressive functional decline associated with alterations in gut microbiota, epithelial barrier dysfunction, and cellular senescence. Although quercetin has been proposed as a potential anti-aging compound, its clinical application is limited by poor bioavailability. In this study, we investigated whether enhancing quercetin bioavailability using EubioQuercetin (EQN) modulates aging-related phenotypes through the gut microbiota–intestinal barrier axis. Methods: Male C57BL/6J mice were treated with EQN or conventional quercetin (CQN) for 12 weeks. External aging phenotypes were assessed using a composite aging score based on hair glossiness, hair loss, and the presence of white hair. Gut microbiota composition was analyzed via 16S rRNA sequencing with centered log-ratio transformation, and intestinal gene expression was assessed by quantitative reverse transcription-polymerase chain reaction. Results: EQN significantly reduced the aging score compared with the control group (median 4.5 vs. 8, p < 0.01), while CQN also showed a moderate reduction. Microbiota analysis identified taxa positively associated with aging (Lactobacillus, Romboutsia, Desulfovibrio, and Lachnoclostridium) and negatively associated taxa (Akkermansia and Christensenellaceae). EQN suppressed aging-associated taxa and partially increased taxa linked to a healthier microbiota profile. At the intestinal level, EQN downregulated senescence-associated genes (p21, PCNA, and Lgr5) and upregulated the tight junction gene claudin-1. In contrast, systemic inflammatory markers and short-chain fatty acids were not significantly associated with the aging score. Conclusions: These findings indicate that enhancing quercetin bioavailability attenuates externally assessed aging phenotypes in aged mice and is associated with coordinated changes in gut microbiota and intestinal gene expression. Modulation of the gut microbiota–intestinal barrier axis may represent a potential mechanism underlying these effects. Full article

Ulcerative colitis is a chronic inflammatory bowel disease that requires new treatment approaches beyond traditional anti-inflammatory drugs. In this study, we analyzed publicly available single-cell RNA sequencing data from a DSS-induced colitis mouse model and identified pyroptosis as a key biological process linked to epithelial damage. Based on this, we screened marine-derived brominated indoles for potential pyroptosis inhibitors and identified 6-bromoindole-3-acetonitrile as a promising candidate. Our results show that this compound significantly alleviates DSS-induced colitis in mice, with notable body weight recovery and a drop in Disease Activity Index (DAI) scores from about 8.5 to below 4 (p < 0.05). At the molecular level, it lowers the mRNA levels of Nlrp3, Caspase-1, and other pyroptosis-related genes, indicating suppression of the pyroptotic pathway. Moreover, treatment helps restore the intestinal barrier by supporting goblet cell regeneration and strengthening tight junctions. Molecular docking suggests that 6-bromoindole-3-acetonitrile binds stably to the active site of myeloperoxidase (MPO), with a binding energy of −18.1 kcal/mol, offering a possible structural basis for its anti-inflammatory effects. Together, these findings point to a marine-derived compound that reduces both inflammation and pyroptosis, representing a promising strategy for treating ulcerative colitis. Notably, these results come from preclinical studies and need further validation in clinical settings. Full article

The gastrointestinal (GI) barrier is a highly coordinated, multilayered defence system that maintains intestinal homeostasis by separating the luminal microbiota from the internal milieu. In liver cirrhosis, this barrier undergoes profound structural and functional disruption, emerging as a central driver of bacterial translocation and infection-related complications. Among these, spontaneous bacterial peritonitis (SBP) represents a major determinant of morbidity, mortality, and disease progression. Barrier failure in cirrhosis is not attributable to a single defect but results from the convergence of multiple interconnected mechanisms. Structural alterations include disruption of epithelial tight junctions and deterioration of the mucus layer, leading to increased intestinal permeability and loss of spatial compartmentalisation. These changes are compounded by microbial dysbiosis, characterised by reduced diversity, depletion of short-chain fatty acid-producing taxa, and expansion of pathobionts. In parallel, cirrhosis-associated immune dysfunction impairs both mucosal and systemic antimicrobial defences, while gut–vascular barrier disruption facilitates systemic dissemination of bacteria and microbial products. The resulting increase in bacterial translocation plays a pivotal role in the pathogenesis of SBP and contributes to systemic inflammation, circulatory dysfunction, and acute decompensation. Importantly, this process establishes a self-amplifying pathogenic loop in which barrier dysfunction, dysbiosis, and immune dysregulation mutually reinforce each other. Recent advances have identified key molecular pathways involved in barrier regulation, including bile acid–FXR signalling and microbiome-derived metabolites, providing novel targets for therapeutic intervention. While current management relies largely on antibiotics and supportive care, emerging strategies aim to restore barrier integrity and modulate the gut–liver axis. A deeper understanding of GI barrier dysfunction offers new opportunities to prevent bacterial translocation and improve clinical outcomes in patients with liver cirrhosis. Full article

Biliary atresia (BA) is a progressive fibroinflammatory cholangiopathy of infancy that rapidly advances to cholestasis, fibrosis, cirrhosis, and liver failure if bile drainage is not restored early. Although Kasai hepatoportoenterostomy (KPE) remains the standard first–line operation, many children still develop recurrent cholangitis, persistent cholestasis, and progressive native liver injury. Increasing evidence indicates that the gut microbiota participates in this clinical course through the gut–liver axis. In BA, dysbiosis may weaken the intestinal barrier, increase translocation of microbe–associated molecular patterns (MAMPs), amplify innate and adaptive immune activation, disturb bile acid signaling, and promote fibrogenic and ferroptosis–related injury. In contrast, beneficial taxa and their metabolites may preserve epithelial integrity, support immune tolerance, maintain bile acid homeostasis, and constrain oxidative stress. This review summarizes current evidence on these contrasting harmful and protective effects, stage–specific microbiome signatures reported before and after KPE, and critically evaluates the present status of microbiota–based biomarkers and interventions. We emphasize that although several microbial signatures and therapeutic approaches are promising, they are not yet ready for routine clinical implementation and require prospective validation with standardized endpoints. Full article

Background/Objectives: Psoriasis and Hashimoto’s thyroiditis are chronic immune-mediated disorders affecting distinct target organs but sharing overlapping pathogenic mechanisms, including gut dysbiosis, impaired intestinal barrier function, and systemic immune dysregulation. Growing evidence highlights the gut–skin and gut–thyroid axes as important interfaces linking microbial alterations to immune-mediated inflammation. This review aims to synthesize current knowledge on gut microbiota alterations in psoriasis and Hashimoto’s thyroiditis, with particular emphasis on intestinal permeability, immune pathways, and microbiome-derived metabolites. Methods: A narrative review of experimental and human observational studies was conducted to evaluate evidence on gut microbiota composition, intestinal barrier integrity, immune regulation, bile acid metabolism, and dietary influences in psoriasis and Hashimoto’s thyroiditis. The relevant literature examining mechanistic pathways and clinical associations was included. Results: Both conditions are associated with altered gut microbial composition, including reduced abundance of short-chain fatty acid–producing taxa, which may impair epithelial barrier integrity and promote systemic immune activation. Increased intestinal permeability and enhanced Th17-driven inflammatory responses are reported in both diseases. Recent studies suggest that dysregulated bile acid metabolism may influence intestinal permeability and immune balance along the gut–skin–thyroid axis, although direct clinical data remain limited. Dietary patterns, particularly anti-inflammatory and Mediterranean diets, are consistently associated with increased microbial diversity, improved metabolic profiles, and reduced systemic inflammation. However, most human evidence is observational. Conclusions: The gut microbiome represents a potential mechanistic link connecting diet, intestinal barrier function, immune regulation, and organ-specific autoimmunity in psoriasis and Hashimoto’s thyroiditis. While microbiome-targeted interventions show biological plausibility, well-designed, mechanistically informed randomized controlled trials are required to establish causality and clinical relevance. Full article

Fructose, a key component of modern diets, is closely linked to the growing prevalence of pediatric obesity and metabolic alterations. Although numerous studies highlight its systemic consequences, including altered carbohydrate and lipid metabolism and increased cardiovascular risk, the direct impact of fructose, particularly its role in modulating mucin composition, a key determinant of the mucosal barrier, remains poorly explored. This study investigated whether fructose supplementation modifies high-fat diet (HFD)-induced changes in duodenal mucin production and whether these effects vary depending on age in animals. To this end, young and adult mice were fed a normal diet (ND), HFD, or an HFD supplemented with 30% fructose (w/v) in drinking water (HFD+Fru) for 16 weeks. Brunner’s glands and villus goblet cells were then analyzed using conventional histochemistry and a panel of lectins to evaluate possible alterations in intestinal mucus glycosylation. Results showed that both HFD and HFD+Fru significantly increased body weight. In young mice, HFD+Fru induced a compensatory mucosal phenotype characterized by increased villus PAS (Periodic Acid–Schiff) reactivity (2% vs. ND), elevated sialylated mucin secretion rate (SSR) in Brunner’s glands (25% vs. ND) and villi (17% vs. ND), and higher SNA (up to 46% vs. ND) and PNA (up to 39% vs. ND) in villus goblet cells. In contrast, adult mice receiving HFD+Fru exhibited a maladaptive response, characterized by a reduction in villus PAS-positive mucins (6% vs. ND), decreased villus SSR (5% vs. ND), diminished sialylation (up to 43% SNA vs. ND) and GlcNAc (up to 50% reduction in WGA vs. ND) in villus goblet cells, and marked loss of fucosylation in Brunner’s glands (81% vs. ND) and villus goblet cells (66% vs. ND). These results reveal that fructose-enriched HFD remodels duodenal mucin O-glycosylation in an age-dependent manner, suggesting that while young mice exhibit transient adaptive responses, prolonged exposure can deplete these mechanisms, leading to a compromised adult epithelial barrier. This age-specific vulnerability may significantly contribute to the pathogenesis of diet-related intestinal disorders and obesity-related complications in later life, highlighting the need for early dietary interventions. Full article

This study investigated whether the therapeutic efficacy of Chinese yam polysaccharide (CYP) against ulcerative colitis (UC) depends on an intact gut microbiota. A dextran sulfate sodium (DSS)-induced colitis mouse model was established, and one treatment group received broad-spectrum antibiotics (ABXs) before CYP administration to deplete the intestinal microbiota. CYP markedly attenuated colonic injury, reduced disease activity, and suppressed inflammatory mediators under both microbiota-intact and microbiota-depleted conditions. CYP also enhanced intestinal barrier integrity, as evidenced by reduced serum endotoxin levels and increased expression of MUC-2, Claudin-1, Occludin, and ZO-1. In addition, CYP improved hepatic antioxidant status by increasing GSH-Px and catalase activities and decreasing malondialdehyde levels. Moreover, CYP reduced the activation of the NF-κB and MAPK signaling pathways, with similar trends observed under microbiota-depleted conditions. Microbiota profiling showed that CYP partially corrected DSS-induced dysbiosis, whereas the ABX + CYP group exhibited distinct microbial patterns with enrichment of carbohydrate-related metabolic pathways predicted by PICRUSt2. Collectively, these findings suggest that CYP retains protective efficacy after antibiotic pretreatment, indicating that its effects may not be exclusively dependent on gut microbiota modulation, possibly involving direct actions on immune and intestinal epithelial cells. Full article

(1) Airborne fine particulate matter (PM_2.5) poses a growing threat to poultry production by impairing intestinal health, disturbing microbial balance, and reducing growth performance. Rosmarinic acid (RA), a natural polyphenol with antioxidant, anti-inflammatory, and gut microbiota-regulating properties, can effectively maintain intestinal homeostasis. To date, its protective effects against PM_2.5-induced intestinal injury in broilers remain largely unclear. This study investigated whether dietary RA supplementation mitigates intestinal damage and microbiota dysbiosis caused by PM_2.5 in broilers and explored the related mechanisms. (2) A total of 144 21-day-old broilers were randomly allocated to three groups, control (CON), PM_2.5 exposure (PM), and PM_2.5 exposure plus rosmarinic acid (RA), with six replicates of eight broilers each. (3) Results indicated that PM_2.5 exposure severely impaired growth performance, whereas dietary RA significantly increased average daily feed intake and average daily gain, decreased the feed-to-gain ratio, and elevated final body weight in broilers. RA significantly attenuated PM_2.5-induced intestinal inflammation, as evidenced by reduced expression of inflammatory cytokines (IL-6 and IFN-γ) and downregulation of key components in the TLR4 signaling pathway (TLR4, MyD88, and NF-κB). Inhaled PM_2.5 exposure impaired the intestinal epithelial barrier, marked by decreased mRNA levels of MUC2 and CLDN1 and increased caspase3 expression. Dietary RA treatment effectively restored these indicators, suggesting its role in maintaining epithelial integrity. Furthermore, RA reshaped the gut microbiota structure, altering both α- and β-diversity. Notably, RA led to a higher proportion of potentially health-promoting bacterial taxa, including Lactobacillus, V9D2013_group, and Oscillospirales, while reducing opportunistic pathogens like Shuttleworthia. (4) In conclusion, RA alleviates PM_2.5-induced intestinal inflammation, reinforces the epithelial barrier, and modulates the intestinal microbiota in broilers, likely through inhibition of the TLR4/NF-κB signaling. These findings reveal a novel mechanism by which RA mitigates pollutant-induced intestinal injury via gut microbiota modulation and TLR4/NF-κB suppression, offering new insights into the gut–lung axis in avian species. Full article

Porcine β-defensin 2 (pBD2) possesses broad-spectrum antimicrobial properties and is crucial for gastrointestinal mucosal repair. Lactic acid bacteria (LAB) serve as optimal vectors for exogenous protein delivery due to their high biosafety, intestinal colonization capacity, and ability to modulate gut microecology. In this study, we engineered a recombinant Lactobacillus paracasei strain (pPG-N1-pBD2/27-2) that efficiently secretes pBD2. In vitro, this recombinant strain significantly enhanced the proliferation and migration of porcine intestinal epithelial cells (IPEC-J2). In vivo, oral administration of pPG-N1-pBD2/27-2 markedly alleviated dextran sulfate sodium (DSS)-induced colitis in mice. This protective effect was evidenced by reduced Disease Activity Index (DAI) scores, prevention of colon shortening, and decreased colonic activities of myeloperoxidase (MPO) and eosinophil peroxidase (EPO), alongside normalized N-acetyl-β-D-glucosaminidase (NAG) levels. Histopathological analysis revealed that the treatment preserved mucosal architecture, including goblet cells and crypts, and fortified the physical barrier by upregulating tight junction proteins. Mechanistically, the recombinant strain suppressed the colonic iNOS/COX-2 inflammatory axis, decreased serum pro-inflammatory cytokines (IL-6, IL-1β, and TNF-α), and elevated the anti-inflammatory cytokine IL-10. Furthermore, it restored systemic immune homeostasis by normalizing the proportions of splenic macrophages, T/B lymphocytes, and natural killer (NK) cells. In conclusion, pPG-N1-pBD2/27-2 mitigates colitis through a dual mechanism: reinforcing the intestinal physical barrier and rebalancing the innate–adaptive immune axis. These findings highlight the potential of pBD2-engineered probiotics as novel biological therapeutics for intestinal inflammatory diseases. Full article

Gut microbiota plays a crucial role in regulating immune system function and shaping immunological responses to pathogens capable of causing infections. Alterations in the composition of the intestinal microbiome are associated with immune system dysfunction and increased susceptibility to infections. Patients with acute myeloid leukemia (AML) are highly susceptible to infections due to immune system deregulation caused by the disease itself, as well as chemotherapy-induced bone marrow aplasia. In these patients, gut microbiota dysbiosis and reduced microbial diversity (i.e., imbalances in the composition and function of intestinal microbes) result from multiple factors, including the underlying disease, neutropenia, dietary factors, use of antibiotics, chemotherapy regimens and prolonged hospitalization. Chemotherapy, for instance, induces damage to the intestinal mucosa and disrupts the epithelial barrier, resulting in deregulation of the intestinal microbiome. Previous studies have reported alterations in the human intestinal microbiome in patients with AML undergoing chemotherapy. Of particular interest is the capacity of some commensal bacteria to modulate the tumor microenvironment and response to chemotherapy. Moreover, increased mortality and reduced overall survival have been reported in patients who have undergone allogeneic stem cell transplantation and exhibit decreased gut microbiome diversity at the time of transplantation. These findings indicate that the composition of gut microbiota may play an important role in the prognosis of AML, especially in relation to therapeutic response. This narrative review summarizes new research into the role of the intestinal microbiome and the underlying alterations observed in patients with AML, resulting from the disease and therapeutic interventions and outlines strategies to improve its function and outcomes. Full article

Owing to the multifactorial nature of inflammatory bowel disease (IBD) pathogenesis, conventional two-dimensional (2D) models inadequately recapitulate the complex in vivo microenvironment. This study sought to develop an immune-microenvironment-integrated intestinal-on-a-chip model to overcome these limitations. A microfluidic chip was engineered to co-culture intestinal epithelial (Caco-2) cells and macrophages, facilitating the simulation of IBD pathological conditions for mechanistic investigations. Following inflammatory stimulation, M0 macrophages polarized into the M1 phenotype, concomitant with the upregulation of pro-inflammatory cytokines, including tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), and interleukin-1 beta (IL-1β). This induction disrupted the expression of tight junction proteins (e.g., zonula occludens-1 [ZO-1]) in Caco-2 cells, thereby compromising epithelial barrier integrity. Infliximab was used as a model drug to inhibit TNF-α and modulate macrophage polarization within the chip, effectively rescuing impaired epithelial barrier integrity. This study establishes a reliable intestinal-on-a-chip model that recapitulates macrophage–epithelial interactions in IBD, providing a robust platform for elucidating the mechanisms underlying intestinal barrier dysfunction and developing targeted therapeutic strategies. Full article

Purpose: Inflammatory bowel disease (IBD) is a chronic inflammatory disorder strongly associated with intestinal microbial dysregulation. Although 5-aminosalicylic acid (5-ASA) is widely used in the clinical management of IBD, its therapeutic efficacy is often limited. To address this, the present study aimed to develop a bifidobacterium-derived extracellular vesicle-based drug delivery system (B-MVs@5-ASA) to enhance the therapeutic outcomes of IBD. Methods: B-MVs were isolated by PEG precipitation and loaded with 5-ASA via sonication to obtain B-MVs@5-ASA. Their morphology, particle size, zeta potential, and encapsulation efficiency were analyzed using TEM, DLS, and UV spectrophotometry. Cellular uptake, cytotoxicity (LDH and NO assays), and anti-inflammatory effects were assessed in RAW 264.7 and Caco-2 cells. A DSS-induced colitis mouse model was established to evaluate therapeutic efficacy. Cytokines (ELISA), colon histopathology (H&E), tight-junction proteins (IF), and gut microbiota composition (16S rRNA sequencing) were systematically analyzed. Results: B-MVs@5-ASA exhibited a particle size of 104.3 ± 2.81 nm and an encapsulation efficiency of 11.14% ± 3.63%. B-MVs@5-ASA exhibited the strongest anti-inflammatory effect in vitro and most effectively alleviated DSS-induced colitis in vivo, outperforming monotherapies in reducing inflammation, tissue damage, and enhancing barrier integrity. B-MVs@5-ASA further promoted goblet cell regeneration and beneficially modulated the gut microbiota by enriching Akkermansia and suppressing Escherichia, thereby restoring microbial homeostasis. Conclusions: B-MVs@5-ASA provides potent anti-inflammatory and mucosal-protective effects by modulating cytokine balance, enhancing epithelial barrier function, and reshaping gut microbiota. These findings highlight probiotic vesicle-based nanoplatforms as a safe and promising strategy for targeted IBD therapy. Full article

The emerging problem that microplastics pose to our society is reflected in the exponential growth in investigations devoted to uncovering their toxicological potential in humans. However, these studies present several limitations, one of the most significant being the use of microplastics that do not represent their environmental counterparts. In this study, we evaluated the impact of two types of polyethylene microplastics (27–32 µm)—non-fluorescent and fluorescent—on the liver and intestine, targeting mitochondria. FVB/n mice were subjected to a subacute exposure to two concentrations representative of human exposure (0.002% (w/w) and 0.006% (w/w)). Both types of microplastics impaired mitochondrial respiration through disruption of NADH-linked pathways, with more pronounced effects at the highest concentration of fluorescent MPs. Electron transport chain complexes, particularly CIII and CIV, were affected, partially explaining the observed alterations in mitochondrial respiratory capacity. An increased SOD and GPx activity supported the link between mitochondrial dysfunction and increased reactive oxygen species overproduction under MPs exposure. Hepatic mitochondrial lipid remodelling was detected following exposure to fluorescent microplastics, while intestinal epithelial cells displayed impaired mitochondrial activity together with compromised cellular integrity, indicative of stress response. In parallel, shifts in gut composition suggest that PE MPs may contribute to intestinal barrier dysfunction. Overall, fluorescent MPs induced more severe mitochondrial and biochemical disturbances in both the liver and the intestine than their non-fluorescent counterparts. Our findings highlight mitochondria as central targets for microplastic-induced toxicity and underscore the need for improved MPs models in toxicological research. Full article