Layered defense: how mucus and tight junctions seal the intestinal barrier

The forecasting power of the mucin-microbiome interplay in livestock respiratory diseases

Complex respiratory diseases are a significant challenge for the livestock industry worldwide. These diseases considerably impact animal health and welfare and cause severe economic losses. One of the first lines of pathogen defense combines the respiratory tract mucus, a highly viscous material primarily composed of mucins, and a thriving multi-kingdom microbial ecosystem. The microbiome-mucin interplay protects from unwanted substances and organisms, but its dysfunction may enable pathogenic infections and the onset of respiratory disease. Emerging evidence also shows that noncoding regulatory RNAs might modulate the structure and function of the microbiome-mucin relationship. This opinion paper unearths the current understanding of the triangular relationship between mucins, the microbiome, and noncoding RNAs in the context of respiratory infections in animals of veterinary interest. There is a need to look at these molecular underpinnings that dictate distinct health and disease outcomes to implement effective prevention, surveillance, and timely intervention strategies tailored to the different epidemiological contexts.

Aflatoxin B1 as a complicit in intestinal damage caused by Eimeria ovinoidalis in lambs: Novel insights to reveal parasite-gut battle

Mycotoxins, unavoidable contaminants in feed and feed ingredients, have the potential to influence the incidence and severity of various diseases upon ingestion. Sheep coccidiosis is an enteric disease caused by protozoa of Eimeria spp. However, the extent to which the presence of aflatoxin b1 (AFB1) synergistically exacerbates damage to intestinal health in lambs with Eimeria remains unclear. 50-day-old female lambs were randomly assigned to a 2 × 2 factorial arrangement of treatments for 15 days to assess the impact of AFB1 exposure on lambs with or without Eimeria (E.) ovinoidalis infection. Our findings reveal that AFB1 synergistically intensifies damage to intestinal health in lambs challenged by E. ovinoidalis. This is evidenced by disruptions to the intestinal microbiota and reductions in the production of short-chain fatty acids. AFB1 further aggravates damage to the cecal mechanical barrier. Additionally, AFB1 contributes to the entry of lipopolysaccharide into the bloodstream, activating the inflammatory response. Interestingly, AFB1 exposure history results in an early peak of oocyst excretion and a decreased number of oocyst excretion in E. ovinoidalis infected lambs. This may be closely linked to the destruction of the intestinal epithelial cell structure and its apoptosis, as indicated by a decreased ratio of Bcl-2 to Bax and increased caspase-3 levels. Mechanistically, proteomics analysis identified mitochondrial dysfunction (inhibition of the oxidative phosphorylation pathway) as the primary factor intensifying intestinal epithelial cell destruction caused by coccidia, exacerbated by AFB1 through the inhibiting the conversion of NADH to NAD+ in the cecum of lambs via down-regulation of the PGC-1α/NRF1/TFAM pathway. Overall, these results offer novel insights into the AFB1 complicity in accelerating intestinal damage caused by E. ovinoidalis in lambs. Targeting the mitochondrial oxidative phosphorylation pathway of the intestine may represent a new therapeutic strategy against the detrimental effects of mycotoxin and coccidia.

Gut flora in multiple sclerosis: implications for pathogenesis and treatment

ABSTRACT

Multiple sclerosis is an inflammatory disorder characterized by inflammation, demyelination, and neurodegeneration in the central nervous system. Although current first-line therapies can help manage symptoms and slow down disease progression, there is no cure for multiple sclerosis. The gut-brain axis refers to complex communications between the gut flora and the immune, nervous, and endocrine systems, which bridges the functions of the gut and the brain. Disruptions in the gut flora, termed dysbiosis, can lead to systemic inflammation, leaky gut syndrome, and increased susceptibility to infections. The pathogenesis of multiple sclerosis involves a combination of genetic and environmental factors, and gut flora may play a pivotal role in regulating immune responses related to multiple sclerosis. To develop more effective therapies for multiple sclerosis, we should further uncover the disease processes involved in multiple sclerosis and gain a better understanding of the gut-brain axis. This review provides an overview of the role of the gut flora in multiple sclerosis.

Huangqin Qingre Chubi Capsule inhibits rheumatoid arthritis by regulating intestinal flora and improving intestinal barrier

Background

Changes in intestinal flora and intestinal barrier in patients with preclinical and diagnosed rheumatoid arthritis (RA) suggest that intestinal flora and intestinal barrier play an important role in the induction and persistence of RA. Huangqin Qingre Chubi Capsule (HQC) is a clinically effective herbal formula for the treatment of RA, but its therapeutic mechanism has not been fully clarified.

Materials and methods

In this study, real-time qPCR (RT-qPCR), 16SrRNA sequencing, Western blot (WB), immunofluorescence and other methods were used to investigate whether HQC inhibited RA.

Results

Based on research in collages-induced arthritis (CIA) model in mice, human colon cancer cell line (Caco-2), and fibroblast-like synoviocytes (FLS) from RA patients, we found that intestinal flora was disturbed in CIA model group, intestinal barrier was damaged, and lipolyaccharide (LPS) level was increased, and HQC could regulate intestinal flora and intestinal barrier and reduce LPS translocation into blood. Antibiotic depletion weakened the anti-RA effect of HQC, and HQC fecal microbiota transplantation alleviated RA pathology. In addition, LPS increased the expression of RA pathologic factors MMP3, Fibronectin and inflammatory factors IL-6, TNF-α, IL-1β and IL-8, indicating that elevated peripheral blood level of LPS was related to RA pathology.

Conclusion

The dysregulation of intestinal flora and the disruption of intestinal barrier are significant factors in the development of RA. HQC improves RA by regulating intestinal flora, intestinal barrier and inhibiting LPS translocation into blood. The study unveiles RA's new pathogenesis and laid a scientific groundwork for advancing HQC therapy for RA.

Potential Probiotic Weizmannia coagulans WC10 Improved Antibiotic-Associated Diarrhea in Mice by Regulating the Gut Microbiota and Metabolic Homeostasis

Antibiotic-associated diarrhea (AAD) is a common side effect of long-term and heavy antibiotic therapy. Weizmannia coagulans (W. coagulans) is an ideal probiotic because of its high viability, stability, and numerous health benefits to the host. In this study, the strains were first screened for W. coagulans WC10 (WC10) with a high combined ability based on their biological properties of gastrointestinal tolerance, adhesion, and short-chain fatty acid production ability. The effect of WC10 on mice with AAD was further evaluated. The results showed that WC10 was effective in improving the symptoms of AAD, effectively restoring antibiotic-induced weight loss, and reducing diarrhea status score and fecal water content. In addition, WC10 decreased the expression of pro-inflammatory cytokines and increased the expression of anti-inflammatory cytokines, alleviated intestinal tissue damage and inflammation, and improved intestinal epithelial barrier function by decreasing serum levels of enterotoxin, DAO, and D-lactic acid, and by increasing the expression of the intestinal mucosal immune factors sIgA and occludin. Importantly, the composition and function of the gut microbiota gradually recovered after WC10 treatment, increasing the number of SCFAs-producing Bifidobacterium and Roseburia. Subsequently, the short-chain fatty acid (SCFA) content was examined and WC10 significantly increased acetate, propionate, and butyrate production. Additionally, metabolomic analysis also showed that WC10 reversed the antibiotic interference with major metabolic pathways. These findings provide a solid scientific basis for the future application of W. coagulans WC10 in the treatment of AAD.

Opioids and the Gastrointestinal Tract: The Role of Peripherally Active µ-Opioid Receptor Antagonists in Modulating Intestinal Permeability

Opioid receptors are found throughout the gastrointestinal tract, including the large intestine. Many patients treated with opioids experience opioid-induced constipation (OIC). Laxatives are not effective in most patients, and in those who do initially respond, the efficacy of laxatives generally diminishes over time. In addition, OIC does not spontaneously resolve for most patients. However, complications of opioids extend far beyond simply slowing gastrointestinal transit. Opioid use can affect intestinal permeability through a variety of mechanisms. Toll-like receptors are a crucial component of innate immunity and are tightly regulated within the gut epithelium. Pathologic µ-opioid receptor (MOR) and toll-like receptor signaling, resulting from chronic opioid exposure, disrupts intestinal permeability leading to potentially harmful bacterial translocation, elevated levels of bacterial toxins, immune activation, and increased cytokine production. Peripherally active MOR antagonists, including methylnaltrexone, are effective at treating OIC. Benefits extend beyond simply blocking the MOR; these agents also act to ameliorate opioid-induced disrupted intestinal permeability. In this review, we briefly describe the physiology of the gastrointestinal epithelial border and discuss the impact of opioids on gastrointestinal function. Finally, we consider the use of peripherally active MOR antagonists to treat disrupted intestinal permeability resulting from opioid use and discuss the potential for improved morbidity and mortality in patients treated with methylnaltrexone for opioid-induced bowel disorders.

Investigating gut microbiota-blood and urine metabolite correlations in early sepsis-induced acute kidney injury: insights from targeted KEGG analyses

Background

The interplay between gut microbiota and metabolites in the early stages of sepsis-induced acute kidney injury (SA-AKI) is not yet clearly understood. This study explores the characteristics and interactions of gut microbiota, and blood and urinary metabolites in patients with SA-AKI.

Methods

Utilizing a prospective observational approach, we conducted comparative analyses of gut microbiota and metabolites via metabolomics and metagenomics in individuals diagnosed with SA-AKI compared to those without AKI (NCT06197828). Pearson correlations were used to identify associations between microbiota, metabolites, and clinical indicators. The Comprehensive Antibiotic Resistance Database was employed to detect antibiotic resistance genes (ARGs), while Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways informed on metabolic processes and microbial resistance patterns.

Results

Our study included analysis of four patients with SA-AKI and five without AKI. Significant disparities in bacterial composition were observed, illustrated by diversity indices (Shannon index: 2.0 ± 0.4 vs. 1.4 ± 0.6, P = 0.230; Simpson index: 0.8 ± 0.1 vs. 0.6 ± 0.2, P = 0.494) between the SA-AKI group and the non-AKI group. N6, N6, N6-Trimethyl-L-lysine was detected in both blood and urine metabolites, and also showed significant correlations with specific gut microbiota (Campylobacter hominis and Bacteroides caccae, R > 0, P < 0.05). Both blood and urine metabolites were enriched in the lysine degradation pathway. We also identified the citrate cycle (TCA cycle) as a KEGG pathway enriched in sets of differentially expressed ARGs in the gut microbiota, which exhibits an association with lysine degradation.

Conclusions

Significant differences in gut microbiota and metabolites were observed between the SA-AKI and non-AKI groups, uncovering potential biomarkers and metabolic changes linked to SA-AKI. The lysine degradation pathway may serve as a crucial link connecting gut microbiota and metabolites.

Polysaccharides extracted from larvae of Lucilia sericata ameliorated ulcerative colitis by regulating the intestinal barrier and gut microbiota

Pest management technology has been a promising bioconversion method for waste resource utilization. Unlike many pests that consume waste, the larvae of Lucilia sericata, also known as maggots, have many outstanding advantages as following: with their strong adaption to environment and not easily infected and exhibiting a medicinal nutritional value. Herein, the potential efficacies of maggot polysaccharides (MP), as well as their underlying mechanisms, were explored in Dextran sulfate sodium (DSS)-induced colitis mice and TNF-α-elicited Caco-2 cells. We extracted two bioactive polysaccharides from maggots, MP-80 and MP-L, whose molecular weights were 4.25 × 103 and 2.28 × 103 g/mol, respectively. MP-80 and MP-L contained nine sugar residues: 1,4-α-Arap, 1,3-β-Galp, 1,4,6-β-Galp, 1,6-α-Glcp, 1-α-Glcp, 1,4-β-Glcp, 1-β-Xylp, 1,2-α-Manp, and 1-β-Manp. We demonstrated that MP-80 and MP-L significantly ameliorated DSS-induced symptoms and histopathological damage. Immuno-analysis revealed that compared with MP-L, MP-80 could better restore intestinal barrier and reduced inflammation by suppressing NLRP3/NF-κB pathways, which might be attributed to its enriched galactose fraction. Moreover, 16S rRNA sequencing revealed that MP-80 and MP-L both improved the dysbiosis and diversity of gut microbiota and acted on multiple microbial functions. Our study sheds new light on the possibility of using maggot polysaccharides as an alternative therapy for colitis.

Recent progress on engineered micro/nanomaterials mediated modulation of gut microbiota for treating inflammatory bowel disease

Inflammatory bowel disease (IBD) is a type of chronic recurrent inflammation disease that mainly includes Crohn's disease and ulcerative colitis. Currently, the treatments for IBD remain highly challenging, with clinical treatment drugs showing limited efficacy and adverse side effects. Thus, developing drug candidates with comprehensive therapeutic effects, high efficiency, and low toxicity is urgently needed. Recently, micro/nanomaterials have attracted considerable interest because of their bioavailability, multitarget and efficient effects on IBD. In addition, gut modulation plays a substantial role in restoring intestinal homeostasis. Therefore, efficient microbiota-based strategies modulating gut microenvironment have great potential in remarkably treating IBD. With the development of micro- and nanomaterials for the treatment of IBD and more in-depth studies of their therapeutic mechanisms, it has been found that these treatments also have a tendency to positively regulate the intestinal flora, resulting in an increase in the beneficial flora and a decrease in the level of pathogenic bacteria, thus regulating the composition of the intestinal flora to a normal state. In this review, we first present the interactions among the immune system, intestinal barrier, and gut microbiome. In addition, recent advances in administration routes and methods that positively arouse the regulation of intestinal flora for IBD using probiotics, prebiotics, and redox-active micro/nanomaterials have been reviewed. Finally, the key challenges and critical perspectives of gut microbiota-based micro/nanomaterial treatment are also discussed.

Gallnut tannic acid alleviates gut damage induced by Salmonella pullorum in broilers by enhancing barrier function and modulating microbiota

Pullorum disease (PD) is a bacterial infection caused by Salmonella pullorum (S. pullorum) that affects poultry. It is highly infectious and often fatal. Antibiotics are currently the mainstay of prophylactic and therapeutic treatments for PD, but their use can lead to the development of resistance in pathogenic bacteria and disruption of the host's intestinal flora. We added neomycin sulfate and different doses of tannic acid (TA) to the drinking water of chicks at 3 days of age and infected them with PD by intraperitoneal injection of S. pullorum at 9 days of age. We analyzed intestinal histopathological changes and the expression of immune-related genes and proteins by using the plate smear method, histological staining, real-time fluorescence quantitative PCR, ELISA kits, and 16S rRNA Analysis of intestinal flora. The results demonstrate that S. pullorum induces alterations in the immune status and impairs the functionality of the liver and intestinal barrier. We found that tannic acid significantly ameliorated S. pullorum-induced liver and intestinal damage, protected the intestinal physical and chemical barriers, restored the intestinal immune barrier function, and regulated the intestinal flora. Our results showed that TA has good anti-diarrhoeal, growth-promoting, immune-regulating, intestinal barrier-protecting and intestinal flora-balancing effects, and the best effect was achieved at an additive dose of 0.2%.

Raspberry Ketone Prevents LPS-Induced Depression-Like Behaviors in Mice by Inhibiting TLR-4/NF-κB Signaling Pathway via the Gut-Brain Axis

SCOPE

Depression, a prevalent mental disorder, has significantly impacted the lives of 350 million people, yet it holds promise for amelioration through food-derived phenolics. Raspberries, renowned globally for their delectable flavor, harbor a phenolic compound known as raspberry ketone (RK). However, the impact of RK on depressive symptoms remains ambiguous. This study aims to investigate the impact of RK on lipopolysaccharide (LPS)-induced depressed mice and elucidates its potential mechanisms, focusing on the gut-brain axis.

METHODS AND RESULTS

Through behavioral tests, RK exerts a notable preventive effect on LPS-induced depression-like behaviors in mice. RK proves capable of attenuating gut inflammation, repairing gut barrier impairment, modulating the composition of the gut microbiome (Muribaculaceae, Streptococcus, Lachnospiraceae, and Akkermansia), and promoting the production of short-chain fatty acids. Furthermore, RK alleviates neuroinflammation by suppressing the TLR-4/NF-κB pathway and bolsters synaptic function by elevating levels of neurotrophic factors and synapse-associated proteins.

CONCLUSION

The current study provides compelling evidence that RK effectively inhibits the TLR-4/NF-κB pathway via the gut-brain axis, leading to the improvement of LPS-induced depression-like behaviors in mice. This study addresses the research gap in understanding the antidepressant effects of RK and illuminates the potential of utilizing RK as a functional food for preventing depression.

The Effects of Resveratrol and Apigenin on Jejunal Oxidative Injury in Ducks and on Immortalized Duck Intestinal Epithelial Cells Exposed to H2O2

Oxidative stress increases the apoptosis of intestinal epithelial cells and impairs intestinal epithelial cell renewal, which further promotes intestinal barrier dysfunction and even death. Extensive evidence supports that resveratrol and apigenin have antioxidant, anti-inflammatory, and antiproliferative properties. Here, we investigated the ability of these two compounds to alleviate diquat-induced jejunal oxidative stress and morphological injury, using the duck as a model, as well as the effects of apigenin on oxidative stress induced by H2O2 in immortalized duck intestinal epithelial cells (IDECs). Ducks were randomly assigned to the following four groups, with five replicates: a control (CON) group, a diquat-challenged (DIQ) group, a resveratrol (500 mg/kg) + diquat (RES) group, and an apigenin (500 mg/kg) + diquat (API) group. We found that serum catalase (CAT) activity and total antioxidant capacity (T-AOC) markedly reduced in the RES and API groups as compared to the DIQ group (p < 0.05); moreover, serum S superoxide dismutase (SOD) levels increased significantly in the API group as compared to the DIQ group (p < 0.05). In jejunal mucosa, the malondialdehyde (MDA) content in the RES and API groups decreased more than that in the DIQ group (p < 0.05). In addition, the jejunal expression levels of the NRF2 and GCLM genes in the RES and API groups increased notably compared with those in the DIQ group (p < 0.05); meanwhile, CAT activity in the RES and API groups was markedly elevated compared with that in the CON group (p < 0.05). In IDECs, apigenin significantly restrained the H2O2-mediated increase in MDA content and decrease in CAT levels (p < 0.05). Furthermore, apigenin increased the protein expression of p-NRF2, NRF2, p-AKT, and p-P38; downregulated that of cleaved caspase-3 and cleaved caspase-9; and reduced the ratio of Bax/Bcl-2 in H2O2-treated IDECs (p < 0.05). In conclusion, resveratrol and apigenin can be used as natural feed additives to protect against jejunal oxidative stress in ducks.

Pellino1 orchestrates gut-kidney axis to perpetuate septic acute kidney injury through activation of STING pathway and NLRP3 inflammasome

AIMS

Intestinal barrier dysfunction is the initial and propagable factor of sepsis in which acute kidney injury (AKI) has been considered as a common life-threatening complication. Our recent study identifies the regulatory role of Pellino1 in tubular death under inflammatory conditions in vitro. The objective of our current study is to explore the impact of Pellino1 on gut-kidney axis during septic AKI and uncover the molecular mechanism (s) underlying this process.

MATERIALS AND METHODS

Immunohistochemistry (IHC) was conducted to evaluate Pellino1 and NOD-like receptor thermal protein domain associated protein 3 (NLRP3) levels in renal biopsies from critically ill patients with a clinical diagnosis of sepsis. Functional and mechanistic studies were characterized in septic models of the Peli-knockout (Peli1-/-) mice by histopathological staining, enzyme-linked immunosorbent assay (ELISA), flow cytometry, immunofluorescence, biochemical detection, CRISPR/Cas9-mediated gene editing and intestinal organoid.

KEY FINDINGS

Pellino1, together with NLRP3, are highly expressed in renal biopsies from critically ill patients diagnosed with sepsis and kidney tissues of septic mice. The Peli1-/- mice with sepsis become less prone to develop AKI and have markedly compromised NLRP3 activation in kidney. Loss of Peli1 endows septic mice refractory to intestinal inflammation, barrier permeability and enterocyte apoptosis that requires stimulator of interferons genes (STING) pathway. Administration of STING agonist DMXAA deteriorates AKI and mortality of septic Peli1-/- mice in the presence of kidney-specific NLRP3 reconstitution.

SIGNIFICANCE

Our studies suggest that Pellino1 has a principal role in orchestrating gut homeostasis towards renal pathophysiology, thus providing a potential therapeutic target for septic AKI.

Atorvastatin attenuates intestinal mucositis induced by 5-fluorouracil in mice by modulating the epithelial barrier and inflammatory response

Chemotherapy-induced intestinal mucositis is a major side effect of cancer treatment. Statins are 3-hydroxy-3-methyl glutaryl coenzyme reductase inhibitors used to treat hypercholesterolemia and atherosclerotic diseases. Recent studies have demonstrated that atorvastatin (ATV) has antioxidant, anti-inflammatory, and resulting from the regulation of different molecular pathways. In the present study, we investigated the effects of ATV on intestinal homeostasis in 5-fluorouracil (5-FU)-induced mucositis. Our results showed that ATV protected the intestinal mucosa from epithelial damage caused by 5-FU mainly due to inflammatory infiltrate and intestinal permeability reduction, downregulation of inflammatory markers, such as Tlr4, MyD88, NF-κB, Tnf-a, Il1β, and Il6 dose-dependent. ATV also improved epithelial barrier function by upregulating the mRNA transcript levels of mucin 2 (MUC2), and ZO-1 and occludin tight junction proteins. The results suggest that the ATV anti-inflammatory and protective effects on 5-FU-induced mice mucositis involve the inhibition of the TLR4/MYD88/NPRL3/NF-κB, iNos, and caspase 3.

Tolypocladium sinense Mycelium Polysaccharide Alleviates Obesity, Lipid Metabolism Disorder, and Inflammation Caused by High Fat Diet via Improving Intestinal Barrier and Modulating Gut Microbiota

SCOPE

Tolypocladium sinense is a fungus isolated from Cordyceps. Cordyceps has some medicinal value and is also a daily health care product. This study explores the preventive effects of T. sinense mycelium polysaccharide (TSMP) on high-fat diet-induced obesity and chronic inflammation in mice.

METHODS AND RESULTS

Here, the study establishes an obese mouse model induced by high-fat diet. In this study, the mice are administered TSMP daily basis to evaluate its effect on alleviating obesity. The results show that TSMP can significantly inhibit obesity and alleviate dyslipidemia by regulating the expression of lipid metabolism-related genes such as liver kinase B1 (LKB1), phosphorylated AMP-activated protein kinase (pAMPK), peroxisome proliferator activated receptor α (PPARα), fatty acid synthase (FAS), and hydroxymethylglutaryl-CoA reductase (HMGCR) in the liver. TSMP can increase the protein expression of zona occludens-1 (ZO-1), Occludin, and Claudin-1 in the colon, improve the intestinal barrier dysfunction, and reduce the level of serum LPS, thereby reducing the inflammatory response. 16S rDNA sequencing shows that TSMP alters the intestinal microbiota by increasing the relative abundance of Akkermansia, Lactobacillus, and Prevotellaceae_NK3B31_group, while decreasing the relative abundance of Faecalibaculum.

CONCLUSION

The findings show that TSMP can inhibit obesity and alleviates obesity-related lipid metabolism disorders, inflammatory responses, and oxidative stress by modulating the gut microbiota and improving intestinal barrier.

In vitro digestion properties of Laiyang pear residue polysaccharides and it counteracts DSS-induced gut injury in mice via modulating gut inflammation, gut microbiota and intestinal barrier

The aim of this study was to explore the dynamic changes in the physicochemical properties of Laiyang pear residue polysaccharide (LPP) during in vitro digestion, as well as its protective effect on the intestines. Monosaccharide composition and molecular weight analysis showed that there was no significant change in LPP during the oral digestion stage. However, during the gastric and intestinal digestion stages, the glycosidic bonds of LPP were broken, leading to the dissociation of large molecular aggregates and a significant increase in reducing sugar content (CR) accompanied by a decrease in molecular weight. In addition, LPP exerted the intestinal protective ability via inhibiting gut inflammation, improving intestinal barrier, and regulating intestinal flora in DSS-induced mice. Specifically, LPP mitigated DSS-induced intestinal pathological damage of mice via enhancing intestinal barrier integrity and upregulating expressions of TJ proteins, and suppressed inflammation by inhibiting NF-κB signaling axis. Furthermore, LPP decreased the ratio of Firmicutes/Bacteroidetes, increased the relative abundance of Lactobacillus, and altered the diversity and the composition of gut microbiota in DSS-induced mice. Therefore, LPP had the potential to be a functional food that improved gut microbiota environment to enhance health and prevent diseases, such as a prebiotic.

Gut microbiota and their derivatives in the progression of colorectal cancer: Mechanisms of action, genome and epigenome contributions

Gut microbiota interacts with host epithelial cells and regulates many physiological functions such as genetics, epigenetics, metabolism of nutrients, and immune functions. Dietary factors may also be involved in the etiology of colorectal cancer (CRC), especially when an unhealthy diet is consumed with excess calorie intake and bad practices like smoking or consuming a great deal of alcohol. Bacteria including Fusobacterium nucleatum, Enterotoxigenic Bacteroides fragilis (ETBF), and Escherichia coli (E. coli) actively participate in the carcinogenesis of CRC. Gastrointestinal tract with chronic inflammation and immunocompromised patients are at high risk for CRC progression. Further, the gut microbiota is also involved in Geno-toxicity by producing toxins like colibactin and cytolethal distending toxin (CDT) which cause damage to double-stranded DNA. Specific microRNAs can act as either tumor suppressors or oncogenes depending on the cellular environment in which they are expressed. The current review mainly highlights the role of gut microbiota in CRC, the mechanisms of several factors in carcinogenesis, and the role of particular microbes in colorectal neoplasia.

Molecular Mechanisms of Lacticaseibacillus rhamnosus, LGG® Probiotic Function

To advance probiotic research, a comprehensive understanding of bacterial interactions with human physiology at the molecular and cellular levels is fundamental. Lacticaseibacillus rhamnosus LGG® is a bacterial strain that has long been recognized for its beneficial effects on human health. Probiotic effector molecules derived from LGG®, including secreted proteins, surface-anchored proteins, polysaccharides, and lipoteichoic acids, which interact with host physiological processes have been identified. In vitro and animal studies have revealed that specific LGG® effector molecules stimulate epithelial cell survival, preserve intestinal barrier integrity, reduce oxidative stress, mitigate excessive mucosal inflammation, enhance IgA secretion, and provide long-term protection through epigenetic imprinting. Pili on the cell surface of LGG® promote adhesion to the intestinal mucosa and ensure close contact to host cells. Extracellular vesicles produced by LGG® recapitulate many of these effects through their cargo of effector molecules. Collectively, the effector molecules of LGG® exert a significant influence on both the gut mucosa and immune system, which promotes intestinal homeostasis and immune tolerance.

Exopolysaccharides Produced by Bifidobacterium longum subsp. longum YS108R Ameliorates DSS-Induced Ulcerative Colitis in Mice by Improving the Gut Barrier and Regulating the Gut Microbiota

Ulcerative colitis (UC) is a major disease that has endangered human health. Our previous study demonstrated that Bifidobacterium longum subsp. longum YS108R, a ropy exopolysaccharide (EPS)-producing bacterium, could alleviate UC in mice, but it is unclear whether EPS is the key substance responsible for its action. In this study, we proposed to investigate the remitting effect of EPS from B. longum subsp. longum YS108R on UC in a DSS-induced UC mouse model. Water extraction and alcohol precipitation were applied to extract EPS from the supernatant of B. longum subsp. longum YS108R culture. Then the animal trial was performed, and the results indicated that YS108R EPS ameliorated colonic pathological damage and the intestinal barrier. YS108R EPS suppressed inflammation via NF-κB signaling pathway inhibition and attenuated oxidative stress via the Nrf2 signaling pathway activation. Remarkably, YS108R EPS regulated gut microbiota, as evidenced by an increase in short-chain fatty acid (SCFA)-producing bacteria and a decline in Gram-negative bacteria, resulting in an increase of propionate and butyrate and a reduction of lipopolysaccharide (LPS). Collectively, YS108R EPS manipulated the intestinal microbiota and its metabolites, which further improved the intestinal barrier and inhibited inflammation and oxidative stress, thereby alleviating UC.

Ferulic Acid Derivatives Ameliorate Intestine Barrier Destruction by Alleviating Inflammatory Responses in Dextran Sulfate Sodium-Induced Inflammatory Bowel Disease

Inflammatory bowel disease (IBD), a chronic disorder affecting the colon and rectum, involves the overproduction of pro-inflammatory cytokines causing damage to tight junctions (TJ) in the intestinal epithelial cells and chronic inflammation. The current mainstay of treatment, sulfasalazine, often causes adverse effects, thereby necessitating the exploration of alternative herbal medicines with fewer side effects. Portulaca oleracea L. (P. oleracea), a traditional medicinal herb, contains feruloyl amide compounds. We synthesized new compounds by conjugating ferulic acid (FA) with (±)-octopamine. Our study focused on novel FA derivatives that demonstrate protective effects against the intestinal epithelial barrier and inflammatory responses. In lipopolysaccharide-induced cells, C1 and C1a inhibited the production of inflammatory mediators. In Caco-2 cells, these compounds maintained the TJ protein expression, thereby demonstrating their protective effects on the epithelial barrier. In a mouse model of dextran sulfate sodium-induced IBD, a treatment with these compounds ameliorated features including a body weight reduction, colon shortening, an increased disease activity index, and histopathological changes. Furthermore, C1a demonstrated greater efficacy than C1 at the same concentration. These findings suggest that the novel FA derivative (C1a) effectively alleviates clinical signs and inflammatory mediators in IBD, making these compounds potential candidates as natural medicines for the treatment of IBD.

4-Phenylbutyric Acid Attenuates Soybean Glycinin/β-Conglycinin-Induced IPEC-J2 Cells Apoptosis by Regulating the Mitochondria-Associated Endoplasmic Reticulum Membrane and NLRP-3

Glycinin (11S) and β-conglycinin (7S) from soybean (glycine max) cause diarrhea and intestinal barrier damage in young animals. Understanding the mechanisms underlying the damage caused by 7S and 11S, it is vital to develop strategies to eliminate allergenicity. Consequently, we investigated 7S/11S-mediated apoptosis in porcine intestinal epithelial (IPEC-J2) cells. IPEC-J2 cells suffered endoplasmic reticulum stress (ERS) in response to 7S and 11S, activating protein kinase RNA-like ER kinase, activating transcription factor 6, C/EBP homologous protein, and inositol-requiring enzyme 1 alpha. 4-Phenylbutyric acid (4-PBA) treatment alleviated ERS; reduced the NLR family pyrin domain containing 3, interleukin-1β, and interleukin-18 levels; inhibited apoptosis; increased mitofusin 2 expression; and mitigated Ca2+ overload and mitochondria-associated ER membrane (MAM) dysfunction, thereby ameliorating IPEC-J2 injury. We demonstrated the pivotal role of ERS in MAM dysfunction and 7S- and 11S-mediated apoptosis, providing insights into 7S- and 11S-mediated intestinal barrier injury prevention and treatment.

Limonin alleviates high-fat diet-induced dyslipidemia by regulating the intestinal barrier via the microbiota-related ILC3-IL22-IL22R pathway

High-fat diet (HFD)-induced dyslipidemia is frequently accompanied by gut microbiota dysbiosis and a compromised gut barrier. Enhancing the intestinal barrier function emerges as a potential therapeutic approach for dyslipidemia. The ILC3-IL22-IL22R pathway, which responds to dietary and microbial signals, has not only attracted attention for its crucial role in maintaining the intestinal barrier, but recent reports have also suggested its potential in regulating lipid metabolism. Limonin is derived from the Chinese herb Evodiae fructus, which has shown potential in ameliorating dysbiosis of serum lipids. However, its underlying mechanisms remain elusive. Consequently, targeting the ILC3-IL22-IL22R pathway to enhance intestinal barrier function holds promise as a therapeutic approach for dyslipidemia. In this study, male C57BL/6 mice were subjected to a 16-week HFD to induce dyslipidemia and concurrently administered oral limonin. We discovered that limonin supplementation dramatically reduced serum lipid profiles in HFD-fed mice, significantly curbing HFD-induced weight gain and epididymal fat accumulation. Ileal histopathological evaluation indicated limonin's ameliorative effects on HFD-induced intestinal barrier impairment. Limonin also moderated the intestinal microbiota dysbiosis, which is characterized by the elevation of Firmicutes in HFD mice, and notably amplified the abundance of probiotic Lactobacillus. In addition, supported by flow cytometry and other analyses, we observed that limonin upregulated the ILC3-IL22-IL22R pathway, enhancing phosphorylated STAT3 (pSTAT3) in intestinal epithelial cells (IECs), thereby reducing lipid transporter expression. In conclusion, our study revealed that limonin exerted a promising preventive effect against HFD-induced dyslipidemia by the mitigation of the intestinal barrier function and intestinal microbiota, and its mechanism was related to the upregulation of the ILC3-IL22-IL22R pathway.

Extracellular polysaccharides from Sporidiobolus pararoseus alleviates rheumatoid through ameliorating gut barrier function and gut microbiota

Rheumatoid arthritis (RA) is becoming a prevalent autoimmune disease affecting people worldwide, necessitating the exploration of novel therapeutic approaches due to the associated adverse effects of conventional therapeutic drugs. Sporidiobolus pararoseus polysaccharide (SPP) has been shown to exhibit significant immune stimulation and antioxidant activities. In this study, we constructed a mouse model of type II collagen-induced arthritis (CIA) to investigate the effects and potential mechanisms of SPP intervention on RA. Results showed that SPP intervention alleviated the degree of ankle swelling, joint histopathologic changes, joint pathological score and the expression of serum-associated inflammatory mediators (such as IL-1β and IL-6). 16S rRNA sequencing results indicated that SPP intervention significantly remodeled the intestinal microbiota composition. In particular, SPP intervention significantly increased the relative abundance of beneficial bacteria (Parabacteroides, Bacteroides and Rikenellaceae_RC9_gut_group) with the potential to degrade fungal polysaccharides or produce short-chain fatty acids (SCFAs). The production of SCFAs (especially acetic acid, propionic acid and butyric acid) indeed increased significantly. These SCFAs played an important role in maintaining intestinal barrier function and regulating immune homeostasis, which helped reduce inflammatory responses and alleviate the symptoms of RA.

Associations between rheumatoid arthritis and intestinal flora, with special emphasis on RA pathologic mechanisms to treatment strategies

BACKGROUND

Rheumatoid arthritis (RA) is an autoimmune inflammatory disease that primarily affects the joints. Individuals at risk for RA and people with RA develop intestinal dysbiosis. The changes in intestinal flora composition in preclinical and confirmed RA patients suggest that intestinal flora imbalance may play an important role in the induction and persistence of RA.

METHODS

Based on the current research on the interaction between RA and intestinal microbiota, intestinal microbiota metabolites and intestinal barrier changes. This paper systematically summarized the changes in intestinal microbiota in RA patients, the metabolites of intestinal flora, and the influence mechanism of intestinal barrier on RA, and further discussed the influence of drugs for RA on intestinal flora and its mechanism of action.

RESULTS

Compared with healthy controls, α diversity analysis of intestinal flora showed no significant difference, β diversity analysis showed significant differences. The intestinal flora produces bioactive metabolites, such as short-chain fatty acids and aromatic amino acids, which have anti-inflammatory effects. Abnormal intestinal flora leads to impaired barrier function and mucosal immune dysfunction, promoting the development of inflammation. Traditional Chinese medicine (TCM) and chemical drugs can also alleviate RA by regulating intestinal flora, intestinal flora metabolites, and intestinal barrier. Intestinal flora is closely related to the pathogenesis of RA and may become potential biomarkers for the diagnosis and treatment of RA.

CONCLUSIONS

Intestinal flora and its metabolites play an important role in the pathogenesis of autoimmune diseases such as RA, and are expected to become a new target for clinical diagnosis and treatment, providing a new idea for targeted treatment of RA.

Essential oils improve nursery pigs' performance and appetite via modulation of intestinal health and microbiota

Optimal intestinal health and functionality are essential for animal health and performance, and simultaneously intestinal nutrient transporters and intestinal peptides are also involved in appetite and feed intake control mechanisms. Given the potential of essential oil (EO) in improving animal performance and improving feed palatability, we hypothesized that dietary supplementation of cinnamaldehyde and carvacrol could improve performance and appetite of nursery pigs by modulating intestinal health and microbiota. Cinnamaldehyde (100 mg/kg), carvacrol (100 mg/kg), and their mixtures (including 50 mg/kg cinnamaldehyde and 50 mg/kg carvacrol) were supplemented into the diets of 240 nursery pigs for 42 d, and data related to performance were measured. Thereafter, the influence of EO on intestinal health, appetite and gut microbiota and their correlations were explored. EO supplementation increased (P < 0.05) the body weight, average daily gain (ADG) and average daily feed intake (ADFI) of piglets, and reduced (P < 0.05) diarrhea rates in nursery pigs. Furthermore, EO increased (P < 0.05) the intestinal absorption area and the abundance of tight junction proteins, and decreased (P < 0.05) intestinal permeability and local inflammation. In terms of intestinal development and the mucus barrier, EO promoted intestinal development and increased (P < 0.05) the number of goblet cells. Additionally, we found that piglets in the EO-supplemented group had upregulated (P < 0.05) levels of transporters and digestive enzymes in the intestine, which were significantly associated with daily gain and feed utilization. In addition, EO supplementation somewhat improved appetite in nursery pigs, increased the diversity of the gut microbiome and the abundance of beneficial bacteria, and there was a correlation between altered bacterial structure and appetite-related hormones. These findings indicate that EO is effective in promoting growth performance and nutrient absorption as well as in regulating appetite by improving intestinal health and bacterial structure.

In vitro mucin degradation and paracellular permeability by fecal water from Crohn's disease patients

Aim: This study aimed to examine the impact of fecal water (FW) of active and remissive Crohn's disease (CD) patients on mucin degradation and epithelial barrier function. Methods: FW and bacterial membrane vesicles (MVs) were isolated from fresh fecal samples of six healthy controls (HCs) and 12 CD patients. Bacterial composition was determined by 16S rRNA gene amplicon sequencing. Results: In vitro FW-induced mucin degradation was higher in CD samples versus HC (p < 0.01), but not associated with specific bacterial genera. FW of three remissive samples decreased transepithelial electrical resistance in Caco-2 cells by 78-87% (p < 0.001). MVs did not induce barrier alterations. Conclusion: The higher mucin-degradation capacity of CD-derived FW might suggest contributions of microbial products to CD pathophysiology.

Reduced Expression of miR-146a Potentiates Intestinal Inflammation following Alcohol and Burn Injury

MicroRNAs (miRNAs) are small noncoding RNA molecules that negatively regulate gene expression. Within the intestinal epithelium, miRNAs play a critical role in gut homeostasis, and aberrant miRNA expression has been implicated in various disorders associated with intestinal inflammation and barrier disruption. In this study, we sought to profile changes in intestinal epithelial cell miRNA expression after alcohol and burn injury and elucidate their impact on inflammation and barrier integrity. Using a mouse model of acute ethanol intoxication and burn injury, we found that small intestinal epithelial cell expression of miR-146a is significantly decreased 1 d following injury. Using in vitro studies, we show that reduced miR-146a promotes intestinal epithelial cell inflammation by promoting p38 MAPK signaling via increased levels of its target TRAF6 (TNFR-associated factor 6). Furthermore, we demonstrate that in vivo miR-146a overexpression significantly inhibits intestinal inflammation 1 d following combined injury and potentially supports intestinal barrier homeostasis. Overall, this study highlights the important impact that miRNA expression can have on intestinal homeostasis and the valuable potential of harnessing aberrant miRNA expression as a therapeutic target to control intestinal inflammation.

Fucoxanthin Alleviates Dextran Sulfate Sodium-Induced Colitis and Gut Microbiota Dysbiosis in Mice

The purpose of this study was to evaluate the preventive role and underlying mechanisms of fucoxanthin (Fx) on dextran sulfate sodium (DSS)-induced colitis in mice. The present data demonstrated that oral administration of Fx (50 and 200 mg/kg body weight/day) for 36 days significantly alleviated the severity of colitis in DSS-treated mice, as evidenced by attenuating body weight loss, bloody stool, diarrhea, shortened colon length, colonic epithelium distortion, a thin mucus layer, goblet cell depletion, damaged crypts, and extensive infiltration of inflammatory cells in the colonic mucosa. Additionally, Fx notably relieved DSS-induced intestinal epithelial barrier dysfunction via maintaining the tight junction function and preventing excessive apoptosis of colonic epithelial cells. Moreover, Fx effectively diminished colonic inflammation and oxidative stress in DSS-treated mice, and its mechanisms might be due to blunting the activation of NF-κB and NLRP3 inflammasome signaling pathways. Furthermore, Fx also modulates DSS-induced gut microbiota dysbiosis via recovering the richness and diversity of gut microbiota and reshaping the structure of gut microbiota, such as increasing the Firmicutes and Bacteroidota (F/B) ratio and elevating the relative abundance of some potential beneficial bacteria, including Lactobacillaceae and Lachnospiraceae. Overall, Fx might be developed as a promising functional ingredient to prevent colitis and maintain intestinal homeostasis.

Adenosine in Intestinal Epithelial Barrier Function

At the intestinal front, several lines of defense are in place to resist infection and injury, the mucus layer, gut microbiome and strong epithelial junctions, to name a few. Their collaboration creates a resilient barrier. In intestinal disorders, such as inflammatory bowel disease (IBD), barrier function is compromised, which results in rampant inflammation and tissue injury. In response to the destruction, the intestinal epithelium releases adenosine, a small but powerful nucleoside that functions as an alarm signal. Amidst the chaos of inflammation, adenosine aims to restore order. Within the scope of its effects is the ability to regulate intestinal epithelial barrier integrity. This review aims to define the contributions of adenosine to mucus production, microbiome-dependent barrier protection, tight junction dynamics, chloride secretion and acid-base balance to reinforce its importance in the intestinal epithelial barrier.

Allopurinol Disrupts Purine Metabolism to Increase Damage in Experimental Colitis

Inflammatory bowel disease (IBD) is marked by a state of chronic energy deficiency that limits gut tissue wound healing. This energy shortfall is partially due to microbiota dysbiosis, resulting in the loss of microbiota-derived metabolites, which the epithelium relies on for energy procurement. The role of microbiota-sourced purines, such as hypoxanthine, as substrates salvaged by the colonic epithelium for nucleotide biogenesis and energy balance, has recently been appreciated for homeostasis and wound healing. Allopurinol, a synthetic hypoxanthine isomer commonly prescribed to treat excess uric acid in the blood, inhibits the degradation of hypoxanthine by xanthine oxidase, but also inhibits purine salvage. Although the use of allopurinol is common, studies regarding how allopurinol influences the gastrointestinal tract during colitis are largely nonexistent. In this work, a series of in vitro and in vivo experiments were performed to dissect the relationship between allopurinol, allopurinol metabolites, and colonic epithelial metabolism and function in health and during disease. Of particular significance, the in vivo investigation identified that a therapeutically relevant allopurinol dose shifts adenylate and creatine metabolism, leading to AMPK dysregulation and disrupted proliferation to attenuate wound healing and increased tissue damage in murine experimental colitis. Collectively, these findings underscore the importance of purine salvage on cellular metabolism and gut health in the context of IBD and provide insight regarding the use of allopurinol in patients with IBD.

[Efficacy of navel application of Jianpiwenyang Gel for chronic diarrhea of spleen and stomach weakness type: a randomized controlled trial and analysis of the mechanism]

OBJECTIVE

To investigate the efficacy of Jianpiwenyang Gel (SSWYG) for treating chronic diarrhea and explore its therapeutic mechanism.

METHODS

Eighty patients with chronic diarrhea of spleen and stomach weakness type were randomized into two groups for interventions with lifestyle adjustment and treatment with bifid triple viable capsules (control group, n=40) or naval application with SSWYG (treatment group, n=40) for one week, after which symptoms of chronic diarrhea were evaluated. The Chinese medicine system pharmacology analysis platform (TCMSP), GeneCards, NCBI, OMIM database and GEO database (GSE14841) were used to obtain the active ingredients and target proteins of SSWYG and chronic diarrhea-related targets. The key targets were obtained by topological analysis for Gene Ontology (GO) and KEGG analyses. The affinity and binding characteristics of SSWYG for specific targets were verified by molecular docking using AutoDock software.

RESULTS

In both groups, gastrointestinal symptom rating scale (GSRS), Bristol Scale and TCM syndrome scores significantly improved after the treatments (P < 0.05), and better effects were observed in the treatment group (P < 0.05). Sixtyeight targets of SSWYG in treating chronic diarrhea were obtained, and 33 most probable ones were screened out by topological analysis. GO and KEGG analyses identified several chronic diarrhea-related pathways including the TNF and IL-17 pathways. Molecular docking study showed good affinity of the core components of SSWYG for the key targets CASP3, JNK, IL1B, IL6, and AKT1. JUN and CASP3 had the lowest binding energy and the highest stable binding energy with multiple major active ingredients of SSWYG.

CONCLUSION

SSWYG can significantly improve clinical symptoms of chronic diarrhea possibly by regulating the TNF and IL-17 as well as other pathways via CASP3 and JUN, suggesting a complex therapeutic mechanism of SSWYG involving multiple ingredients and targets and coordinated regulation of multiple pathways.

Preventive effect of Lacticaseibacillus rhamnosus 2016SWU.05.0601 and its postbiotic elements on dextran sodium sulfate-induced colitis in mice

Microbial-based therapies are one of the hotspots in the field of ulcerative colitis research. The lactic acid bacteria and their postbiotics occupy a key position in microbial therapies, however, the mechanism by which they alleviate ulcerative colitis in mice is unknown. We investigated the effects of Lacticaseibacillus rhamnosus 2016SWU.05.0601 (Lr-0601) and its postbiotics on male Kunming mice with dextran sulfate sodium salt (DSS)-induced ulcerative colitis (UC). The results showed that Lr-0601 significantly alleviated the deterioration of UC and restored the expression of intestinal mechanical barrier proteins. In addition, Lr-0601 significantly reduced the expression of inflammatory cytokines in the body and regulated the expression of key regulatory genes of the NF-κB-iNOS/COX-2 signaling pathway in colon tissues to a large extent. Our results suggest that supplementation with Lr-0601 and its postbiotics can effectively prevent DSS-induced UC and have a beneficial effect on intestinal health, which also provides new insights and research bases for the prevention as well as the treatment of ulcerative colitis and other diseases related to intestinal barrier dysfunction and other diseases.

A novel on-a-chip system with a 3D-bioinspired gut mucus suitable to investigate bacterial endotoxins dynamics

The possible pathogenic impact of pro-inflammatory molecules produced by the gut microbiota is one of the hypotheses considered at the basis of the biomolecular dialogue governing the microbiota-gut-brain axis. Among these molecules, lipopolysaccharides (LPS) produced by Gram-negative gut microbiota strains may have a potential key role due to their toxic effects in both the gut and the brain. In this work, we engineered a new dynamic fluidic system, the MINERVA device (MI-device), with the potential to advance the current knowledge of the biological mechanisms regulating the microbiota-gut molecular crosstalk. The MI-device supported the growth of bacteria that are part of the intestinal microbiota under dynamic conditions within a 3D moving mucus model, with features comparable to the physiological conditions (storage modulus of 80 ± 19 Pa, network mesh size of 41 ± 3 nm), without affecting their viability (∼ 109 bacteria/mL). The integration of a fluidically optimized and user-friendly design with a bioinspired microenvironment enabled the sterile extraction and quantification of the LPS produced within the mucus by bacteria (from 423 ± 34 ng/mL to 1785 ± 91 ng/mL). Compatibility with commercially available Transwell-like inserts allows the user to precisely control the transport phenomena that occur between the two chambers by selecting the pore density of the insert membrane without changing the design of the system. The MI-device is able to provide the flow of sterile medium enriched with LPS directly produced by bacteria, opening up the possibility of studying the effects of bacteria-derived molecules on cells in depth, as well as the assessment and characterization of their effects in a physiological or pathological scenario.

Progress on the mechanisms of Lactobacillus plantarum to improve intestinal barrier function in ulcerative colitis

Ulcerative colitis (UC) is a chronic, non-specific inflammatory sickness of the intestinal tract, chiefly implicating the rectum and colon, which is characterized by chronic or subacute diarrhea, mucopurulent stools, and abdominal pain. The pathogeny of UC is still uncertain, and it is thought that multiple factors interact to cause the disease, such as environment, genetics, gut microbes, and immunity. Injuring the intestinal barrier is one of the most significant features of UC and includes mechanical, chemical, immune, and biological barriers. Plenty of research has shown that probiotics, as profitable bacteria in the gut, can play a prominent role in the treatment of UC by improving gut barrier function and modulating gut immunity. Lactobacillus plantarum (L. plantarum), a common probiotic, has made outstanding contributions to food and medicine, and many studies in recent years have shown that L. plantarum has great preventive and therapeutic effects on ulcerative colitis and restores the intestinal barrier. This paper reviews the mechanisms of L. plantarum for improving the intestinal barrier function of UC organisms, mainly including regulating the immune response, inhibiting oxidative stress, raising the expression of tight junction (TJ) proteins, promoting the formation of mucin, improving the composition of gut flora, and raising the levels of short-chain fatty acids (SCFAs), which offers some help for the clinical therapy of UC.

The traditional herb Sargentodoxa cuneata alleviates DSS-induced colitis by attenuating epithelial barrier damage via blocking necroptotic signaling

ETHNOPHARMACOLOGICAL RELEVANCE

The traditional Chinese herb, Sargentodoxa cuneata, is primarily utilized as a crucial herb for managing ulcerative colitis (UC), also known as "Da Xue Teng (DXT)" or "Hong Teng" in Chinese. Nevertheless, the chemical composition, prototype, and metabolite constituents of DXT and its pharmacological mechanism of treatment for UC remain unclear.

AIM OF THE STUDY

Necroptosis, a caspase-independent form of programmed cell death, plays a crucial role in the inflammatory pathogenesis of UC. The occurrence of necroptosis in intestinal epithelial cells triggers a robust inflammatory response and disrupts the integrity of both the mucinous barrier and tight junction construction. The objective of our study was to determine the chemical composition of DXT, identify its absorbed active ingredients and metabolites in rat serum, and investigate whether DXT possesses epithelial barrier protective effects by inhibiting necroptosis.

MATERIALS AND METHODS

First, the UPLC-Q-TOF/MS was applied to identify the chemical composition of DXT, as well as the absorption components and metabolites of DXT in rat serum. Second, the network pharmacology analysis was further investigated to elucidate the potential targets for treating UC. Finally, the mechanism of action was validated by necroptosis-based experiment in vitro and an in vivo model of colitis.

RESULTS

A comprehensive analysis revealed the presence of 31 phytochemicals derived from DXT herb, as well as a total of 39 components in rat serum. Network pharmacology analysis indicated that TNF, EGFR, HSP90, etc. are the potential targets. Experimental in vitro and in vivo verified that the DXT could improve disease activity index, body weight, colon length and intestinal barrier permeability in mice with colitis by inhibiting necroptosis of intestinal epithelial cells.

CONCLUSIONS

In this study, the phytochemicals derived from DXT herb and absorption active ingredients and metabolites of DXT in rat serum were analyzed. The biological mechanism of treatment for UC can be elucidated by combining network pharmacology investigation with experimental in vitro and in vivo studies. The findings offered a theoretical basis for comprehending the bioactive substances and the pharmacological process of DXT.

Faecalibacterium prausnitzii as a potential Antiatherosclerotic microbe

BACKGROUND

The gut microbiota plays a crucial role in coronary artery disease (CAD) development, but limited attention has been given to the role of the microbiota in preventing this disease. This study aimed to identify key biomarkers using metagenomics and untargeted metabolomics and verify their associations with atherosclerosis.

METHODS

A total of 371 participants, including individuals with various CAD types and CAD-free controls, were enrolled. Subsequently, significant markers were identified in the stool samples through gut metagenomic sequencing and untargeted metabolomics. In vivo and in vitro experiments were performed to investigate the mechanisms underlying the association between these markers and atherosclerosis.

RESULTS

Faecal omics sequencing revealed that individuals with a substantial presence of Faecalibacterium prausnitzii had the lowest incidence of CAD across diverse CAD groups and control subjects. A random forest model confirmed the significant relationship between F. prausnitzii and CAD incidence. Notably, F. prausnitzii emerged as a robust, independent CAD predictor. Furthermore, our findings indicated the potential of the gut microbiota and gut metabolites to predict CAD occurrence and progression, potentially impacting amino acid and vitamin metabolism. F. prausnitzii mitigated inflammation and exhibited an antiatherosclerotic effect on ApoE-/- mice after gavage. This effect was attributed to reduced intestinal LPS synthesis and reinforced mechanical and mucosal barriers, leading to decreased plasma LPS levels and an antiatherosclerotic outcome.

CONCLUSIONS

Sequencing of the samples revealed a previously unknown link between specific gut microbiota and atherosclerosis. Treatment with F. prausnitzii may help prevent CAD by inhibiting atherosclerosis.

Short Chain Fatty Acids: Essential Weapons of Traditional Medicine in Treating Inflammatory Bowel Disease

Inflammatory bowel disease (IBD) is a chronic and recurrent intestinal inflammatory disease, mainly including Crohn's disease (CD) and ulcerative colitis (UC). In recent years, the incidence and prevalence of IBD have been on the rise worldwide and have become a significant concern of health and a huge economic burden on patients. The occurrence and development of IBD involve a variety of pathogenic factors. The changes in short-chain fatty acids (SCFAs) are considered to be an important pathogenic mechanism of this disease. SCFAs are important metabolites in the intestinal microbial environment, which are closely involved in regulating immune, anti-tumor, and anti-inflammatory activities. Changes in metabolite levels can reflect the homeostasis of the intestinal microflora. Recent studies have shown that SCFAs provide energy for host cells and intestinal microflora, shape the intestinal environment, and regulate the immune system, thereby regulating intestinal physiology. SCFAs can effectively reduce the incidence of enteritis, cardiovascular disease, colon cancer, obesity, and diabetes, and also play an important role in maintaining the balance of energy metabolism (mainly glucose metabolism) and improving insulin tolerance. In recent years, many studies have shown that numerous decoctions and natural compounds of traditional Chinese medicine have shown promising therapeutic activities in multiple animal models of colitis and thus attracted increasing attention from scientists in the study of IBD treatment. Some of these traditional Chinese medicines or compounds can effectively alleviate colonic inflammation and clinical symptoms by regulating the generation of SCFAs. This study reviews the effects of various traditional Chinese medicines or bioactive substances on the production of SCFAs and their potential impacts on the severity of colonic inflammation. On this basis, we discussed the mechanism of SCFAs in regulating IBD-associated inflammation, as well as the related regulatory factors and signaling pathways. In addition, we provide our understanding of the limitations of current research and the prospects for future studies on the development of new IBD therapies by targeting SCFAs. This review may widen our understanding of the effect of traditional medicine from the view of SCFAs and their role in alleviating IBD animal models, thus contributing to the studies of IBD researchers.

The Current and Promising Oral Delivery Methods for Protein- and Peptide-Based Drugs

Drugs based on peptides and proteins (PPs) have been widely used in medicine, beginning with insulin therapy in patients with diabetes mellitus over a century ago. Although the oral route of drug administration is the preferred one by the vast majority of patients and improves compliance, medications of this kind due to their specific chemical structure are typically delivered parenterally, which ensures optimal bioavailability. In order to overcome issues connected with oral absorption of PPs such as their instability depending on digestive enzymes and pH changes in the gastrointestinal (GI) system on the one hand, but also their limited permeability across physiological barriers (mucus and epithelium) on the other hand, scientists have been strenuously searching for novel delivery methods enabling peptide and protein drugs (PPDs) to be administered enterally. These include utilization of different nanoparticles, transport channels, substances enhancing permeation, chemical modifications, hydrogels, microneedles, microemulsion, proteolytic enzyme inhibitors, and cell-penetrating peptides, all of which are extensively discussed in this review. Furthermore, this article highlights oral PP therapeutics both previously used in therapy and currently available on the medical market.

BDE-209-induced genotoxicity, intestinal damage and intestinal microbiota dysbiosis in zebrafish (Danio Rerio)

The environmental presence of polybrominated diphenyl ethers (PBDEs) is ubiquitous due to their wide use as brominated flame retardants in industrial products. As a common congener of PBDEs, decabromodiphenyl ether (BDE-209) can pose a health risk to animals as well as humans. However, to date, few studies have explored BDE-209's toxic effects on the intestinal tract, and its relevant mechanism of toxicity has not been elucidated. In this study, adult male zebrafish were exposed to BDE-209 at 6 μg/L, 60 μg/L and 600 μg/L for 28 days, and intestinal tissue and microbial samples were collected for analysis to reveal the underlying toxic mechanisms. Transcriptome sequencing results demonstrated a dose-dependent pattern of substantial gene differential expression in the group exposed to BDE-209, and the differentially expressed genes were mainly concentrated in pathways related to protein synthesis and processing, redox reaction, and steroid and lipid metabolism. In addition, BDE-209 exposure caused damage to intestinal structure and barrier function, and promoted intestinal oxidative stress, inflammatory response, apoptosis and steroid and lipid metabolism disorders. Mechanistically, BDE-209 induced intestinal inflammation by increasing the levels of TNF-α and IL-1β and activating the NFκB signaling pathway, and might induce apoptosis through the p53-Bax/Bcl2-Caspase3 pathway. BDE-209 also significantly inhibited the gene expression of rate-limiting enzymes such as Sqle and 3βhsd (p < 0.05) to inhibit cholesterol synthesis. In addition, BDE-209 induced lipid metabolism disorders through the mTOR/PPARγ/RXRα pathway. 16S rRNA sequencing results showed that BDE-209 stress reduced the richness and diversity of intestinal microbiota, and reduced the abundance of probiotics (e.g., Bifidobacterium and Faecalibacterium). Overall, the results of this study help to clarify the intestinal response mechanism of BDE-209 exposure, and provide a basis for evaluating the health risks of BDE-209 in animals.

Dietary Eucommia ulmoides leaf extract improves laying performance by altering serum metabolic profiles and gut bacteria in aged laying hens

The leaves of Eucommia ulmoides are rich in bioactive constituents that have potential gastrointestinal benefits for animals. In aged laying hens, intestinal health issues contribute to a significant decline in egg-laying capacity during intermediate and later stages. It remains unclear whether E. ulmoides leaf extract (ELE) can improve intestinal health and enhance egg production in elderly laying hens, and the underlying mechanisms are yet to be elucidated. Therefore, we conducted a study with 480 laying hens (65 weeks old) randomly allocated into four groups: a control group fed with the basal diet, and three treatment groups supplemented with 500, 1,000, and 2,000 mg/kg of ELE, respectively. The primary active constituents of ELE include flavonoids, polysaccharides, terpenoids, and phenolic acids. Dietary supplementation with ELE at 1,000 mg/kg (ELE1000) significantly improved laying performance and egg quality compared to the other groups. ELE1000 stimulated the maturation of intestinal epithelial cells, increased villus height, and reduced crypt depth. It also influenced the levels of proteins associated with tight junctions (claudin-1 and claudin-2) and intestinal inflammatory factors (IL-6, IL-1β, and IL-2) in different intestinal sections. Integrative analysis of serum metabolomics and gut microbiota revealed that ELE1000 improved nutrient metabolism by modulating amino acid and ubiquinone biosynthesis and influenced the abundance of intestinal microbiota by enriching pivotal genera such as Bacteroides and Rikenellaceae_RC9_gut_group. We identified 15 metabolites significantly correlated with both gut microbiota and laying performance, e.g., DL-methionine sulfoxide, THJ2201 N-valerate metabolite, tetracarbonic acid, etc. In conclusion, ELE1000 improved laying performance in elderly laying hens by affecting intestinal morphology, barrier function, microbiota, and serum metabolite profiles. These findings suggest that ELE can be a beneficial feed additive for extending the peak producing period in aged laying hens.

Methyl cinnamate protects against dextran sulfate sodium-induced colitis in mice by inhibiting the MAPK signaling pathway

Effective and non-toxic therapeutic agents are lacking for the prevention and treatment of colitis. Previous studies found that methyl cinnamate (MC), extracted from galangal ( Alpinia officinarum Hance), has anti-inflammatory properties. However, whether MC is effective as anti-colitis therapy remains unknown. In this study, we investigate the therapeutic effects of MC on dextran sulfate sodium (DSS)-induced colitis in mice and further explore its potential mechanism of action. MC treatment relieves symptoms associated with DSS-induced colitis, including the recovery of DSS-induced weight loss, decreases the disease activity index score, and increases the colon length without toxic side effects. MC treatment protects the integrity of the intestinal barrier in mice with DSS-induced colitis and inhibits the overexpression of pro-inflammatory cytokines in vivo and in vitro. Moreover, the MAPK signaling pathway is found to be closely related to the treatment with MC of colitis. Western blot analysis show that phosphorylation of the p38 protein in colon tissues treated with MC is markedly reduced and phosphorylation levels of the p38, JNK and ERK proteins are significantly decreased in RAW 264.7 cells treated with MC, indicating that the mechanism of MC in treating DSS-induced colitis could be achieved by inhibiting the MAPK signaling pathway. Furthermore, 16S RNA sequencing analysis show that MC can improve intestinal microbial dysbiosis in mice with DSS-induced colitis. Altogether, these findings suggest that MC may be a novel therapeutic candidate with anti-colitis efficacy. Furthermore, MC treatment relieves the symptoms of colitis by inhibiting the MAPK signaling pathway and improving the intestinal microbiota.

Comparison between local abdominal and transcutaneous tail vein photobiomodulation in experimental rat model of ulcerative colitis

Ulcerative colitis (UC) is a chronic autoimmune disease that impacts the quality of life, but current pharmacological treatments are limited. Photobiomodulation (PBM) is a light-based treatment that can be applied either locally or systemically. Here, we compare the effects of local and vascular PBM (VPBM) in an experimental rat model of UC. Male Wistar rats were induced with UC by rectal instillation of acetic acid and treated with either local abdominal PBM or VPBM to the tail vein using a 660-nm LED. The findings indicated that local PBM but not VPBM reduced intestinal histological scores. Both local and VPBM increased mucus production, decreased mast cell degranulation, and modulated TNF-α and IL-1 β levels in the intestines. Local PBM also affected the expression of the mRNAs for IL-6, TNF-α, and IFN-γ. In conclusion, we suggest that local PBM appears to be more promising than VPBM for treating UC. However, further research is needed to fully understand the mechanisms and to optimize the parameters of PBM for UC treatment.

Gut Bacterial Community Determines the Therapeutic Effect of Ginsenoside on Canine Inflammatory Bowel Disease by Modulating the Colonic Mucosal Barrier

Inflammatory bowel disease (IBD) comprises systemic inflammatory conditions primarily affecting the gastrointestinal tract, including Crohn's disease and ulcerative colitis. This research aims to analyze the clinical symptoms and pathogenesis of a Dextran sodium sulfate (DSS)-induced canine IBD model and evaluate the restorative effect of ginsenoside from a pathogenesis perspective. We established the DSS-induced canine IBD model and studied the pathological mechanisms. Additionally, we examined the therapeutic effect of ginsenosides by assessing the Canine Inflammatory Bowel Disease Activity Index (CIBDAI), C-reactive protein (CRP) levels, colonic tissue morphology, protein expression, and mucosal bacterial community analysis. Our findings revealed a total ginsenoside content of 22.7% in the ginsenoside extract. Animal experiments demonstrated that dogs with IBD exhibited decreased mental state, significantly increased CIBDAI and CRP levels, disrupted colonic epithelial tissue structure, decreased expression of mucin, tight junctions, and adherens junctions, as well as reduced diversity of the colonic mucosal bacterial community. Furthermore, correlation analysis highlighted a total of 38 bacterial strains correlated with physiological indices. Significantly, ginsenoside treatment could improve these symptoms and reverse the relative abundance of some bacterial communities. In conclusion, alterations in the properties of the colonic mucus layer or the reduction in MUC2, its core component, in dogs with IBD can lead to bacterial penetration of the mucus layer and subsequent contact with intestinal epithelial cells, resulting in inflammation. Remarkably, ginsenoside intervention showcased the capacity to positively influence the relative abundance of bacteria and impact the colonic mucus layer properties, thereby offering promising prospects for IBD management and recovery.

Targeting gut-liver axis by dietary lignans ameliorate obesity: evidences and mechanisms

An imbalance between energy consumption and energy expenditure causes obesity. It is characterized by increased adipose accumulation and accompanied by chronic low-grade inflammation. Many studies have suggested that the gut microbiota of the host mediates the relationship between high-fat diet consumption and the development of obesity. Diet and nutrition of the body are heavily influenced by gut microbiota. The alterations in the microbiota in the gut may have effects on the homeostasis of the host's energy levels, systemic inflammation, lipid metabolism, and insulin sensitivity. The liver is an important organ for fat metabolism and gut-liver axis play important role in the fat metabolism. Gut-liver axis is a bidirectional relationship between the gut and its microbiota and the liver. As essential plant components, lignans have been shown to have different biological functions. Accumulating evidences have suggested that lignans may have lipid-lowering properties. Lignans can regulate the level of the gut microbiota and their metabolites in the host, thereby affecting signaling pathways related to fat synthesis and metabolism. These signaling pathways can make a difference in inhibiting fat accumulation, accelerating energy metabolism, affecting appetite, and inhibiting chronic inflammation. It will provide the groundwork for future studies on the lipid-lowering impact of lignans and the creation of functional meals based on those findings.

Konjac glucomannan-assisted curcumin alleviated dextran sulfate sodium-induced mice colitis via regulating immune response and maintaining intestinal barrier integrity

Curcumin has been proven to be an effective strategy for reducing inflammatory responses. However, low bioavailability and instability at the physiological pH have limited its anti-inflammatory activity in ulcerative colitis patients. In the present study, a complex of curcumin and konjac glucomannan (KGM) effectively inhibited intestinal inflammation and this effect was associated with KGM degradation degrees. Results demonstrated that treatment with the complex markedly mitigated colitis symptoms and decreased inflammatory cytokines levels, especially in the complex treatment groups with K110 (KGM treated in 110 °C) and konjac oligosaccharides (KOSs). Furthermore, increasing the KOS content in KOC (the complex of curcumin and KOS) promoted the gene expressions of the intestinal barrier and inhibited the gene expressions of inflammatory cytokines, as well as improved gut microbiota dysregulation. Overall, our studies suggest that the complex of curcumin and KGM exerts effective anti-inflammatory effects by regulating the intestinal immune response and modulating microbiota diversity and composition.

The interconnection between obesity and executive function in adolescence: The role of the gut microbiome

In the United States, adolescent obesity is a growing epidemic associated with maladaptive executive functioning. Likewise, data link the microbiome to obesity. Emerging microbiome research has demonstrated an interconnection between the gut microbiome and the brain, indicating a bidirectional communication system within the gut-microbiome-brain axis in the pathophysiology of obesity. This narrative review identifies and summarizes relevant research connecting adolescent obesity as it relates to three core domains of executive functioning and the contribution of the gut microbiome in the relationship between obesity and executive functions in adolescence. The review suggests that (1) the interconnection between obesity, executive function, and the gut microbiome is a bidirectional connection, and (2) the gut microbiome may mediate the neurobiological pathways between obesity and executive function deficits. The findings of this review provide valuable insights into obesity-associated executive function deficits and elucidate the possible mediation role of the gut microbiome.

Lactobacillus salivarius CPU-01 Ameliorates Temozolomide-Induced Intestinal Mucositis by Modulating Gut Microbiota, Maintaining Intestinal Barrier, and Blocking Pro-inflammatory Cytokines

Chemotherapy-induced intestinal mucositis is one of the major toxic side effects in the treatment of cancer patients. The purpose of this study is to screen lactic acid bacteria which could alleviate intestinal inflammation and damage induced by chemotherapeutic agents and explore the possible underlying mechanisms. Lactobacillus salivarius CPU-01 was selected from traditional Chinese fermented foods due to its protective effects on the toxicity of temozolomide in Caenorhabditis elegans. Eighteen ICR mice were randomly divided into 3 groups including control group, temozolomide-induced intestinal mucositis group, and temozolomide + L. salivarius CPU-01 group, and were used to investigate the effect of L. salivarius CPU-01 on chemotherapy-induced intestinal mucositis. It has been demonstrated that the administration of L. salivarius CPU-01 can prevent colon shortening and alleviate colon tissue damage caused by temozolomide-induced intestinal mucositis in mice. L. salivarius CPU-01 relieved the intestinal microbiota disorders caused by temozolomide and contributed to the growth of beneficial bacteria, such as Lactobacillus, Clostridia UCG - 014_norank, and Akkermansia. In vivo experiments also indicated that L. salivarius CPU-01 can suppress the level of temozolomide-induced pro-inflammatory cytokines in serum and mRNA expression in the small intestine tissues. It was also found that L. salivarius CPU-01 significantly increased the expressions of intestinal tight junction (TJ) proteins, ZO-1, and Occludin proteins in mice treated with temozolomide. These findings suggest that L. salivarius CPU-01 can ameliorate temozolomide-induced intestinal mucositis by modulating gut microbiota, blocking pro-inflammatory cytokines, and repairing the intestinal barrier. These findings suggest probiotics may serve as a potential alternative therapeutic strategy for the prevention of chemotherapy-induced intestinal mucositis in the future.

Terpenes: Modulating anti-inflammatory signaling in inflammatory bowel disease

Inflammatory Bowel Disease (IBD) are autoimmune diseases characterized by chronic intestinal inflammation. Considered a western disease, IBD incidence in newly developed countries is skyrocketing. Accordingly, global prevalence is steadily increasing. There are two major IBD phenotypes, ulcerative colitis (UC) and Crohn's disease (CD). UC manifests as uninterrupted inflammation localized in the colon and rectum. Meanwhile, CD presents as interrupted inflammation that can occur throughout the digestive tract. As a result, therapeutics have focused on anti-inflammatory approaches for its treatment. Unfortunately, only 50% of patients benefit from current Food and Drug Administration approved treatments, and all are associated with serious adverse effects. Thus, there is a need for safer and novel therapeutics to increase the efficacy in this population. One aspect that is critical in understanding IBD is how food and phytochemicals therein may be associated with modifying the pathogenesis of IBD. A variety of retrospective and prospective studies, and clinical trials have shown benefits of plant-rich diets on the prevention and symptomatic improvement of IBD. The Mediterranean diet is rich in vegetables, fruits, legumes, and herbs; and characterized by the abundance of anti-inflammatory phytochemicals. An understudied phytochemical class enriched in this diet is terpenes; isoprene-based molecules are widely available in Mediterranean herbs and citrus fruits. Various terpenes have been evaluated in different IBD models. However, some present contradictory or inconclusive results. Therefore, in this review we evaluated preclinical studies of terpenes modulating basic inflammatory signaling related to IBD.

Protopine Alleviates Dextran Sodium Sulfate-Induced Ulcerative Colitis by Improving Intestinal Barrier Function and Regulating Intestinal Microbiota

Ulcerative colitis (UC) is an inflammatory bowel disease (IBD), and its pathogenesis is related to intestinal mucosal barrier damage and gut microbiota imbalance. Protopine (PRO), an isoquinoline alkaloid, is one of the main anti-inflammatory ingredients of traditional Chinese medicine Macleaya cordata(Willd.) R. Br. This study investigated the effects of PRO on the intestinal mucosal barrier and gut microbiota in dextran sodium sulfate (DSS)-induced colitis mice. C57BL/6J mice were treated with 3% DSS in drinking water to induce acute colitis, while PRO was administered orally once daily for 7 days. The results showed that PRO administration significantly alleviated the symptoms of DSS-induced colitis in mice and inhibited the expression of inflammation-related genes. In addition, PRO restored the integrity of the intestinal barrier in colitis mice by restoring colonic mucin secretion and promoting the expression of tight junction proteins. Furthermore, PRO alleviated the DSS-induced gut microbiota dysbiosis by decreasing the abundance of Proteobacteria, Escherichia-Shigella and Enterococcus, as well as enhancing the abundance of beneficial bacteria, such as Firmicutes and Akkermansia. These findings suggested that PRO effectively alleviated DSS-induced ulcerative colitis by suppressing the expression of inflammation-related genes, maintaining the intestinal mucosal barrier and regulating the intestinal microbiota.

Recent advances in mucus-penetrating nanomedicines for oral treatment of colonic diseases

INTRODUCTION

Oral administration is the most common route for treating colonic diseases that present increased incidences in recent years. Colonic mucus is a critical rate-limiting barrier for the accumulation of oral therapeutics in the colonic tissues. To overcome this obstacle, mucus-penetrating nanotherapeutics have been exploited to increase the accumulated amounts of drugs in the diseased sites and improve their treatment outcomes against colonic diseases.

AREAS COVERED

In this review, we introduce the structure and composition of colonic mucus as well as its impact on the bioavailability of oral drugs. We also introduce various technologies used in the construction of mucus-penetrating nanomedicines (e.g. surface modification of polymers, physical means and biological strategies) and discuss their mechanisms and potential techniques for improving mucus penetration of nanotherapeutics.

EXPERT OPINION

The mucus barrier is often overlooked in oral drug delivery. The weak mucus permeability of conventional medications greatly lowers drug bioavailability. This challenge can be addressed through physical, chemical and biological technologies. In addition to the reported methods, promising approaches may be discovered through interdisciplinary research that further helps enhance the mucus penetration of nanomedicines.