The role of goblet cells and mucus in intestinal homeostasis

CXCR2, as a key regulatory gene of HDP-PG-1, maintains intestinal mucosal homeostasis

The intestine defends against pathogenic microbial invasion via the secretion of host defense peptides (HDPs). Nutritional immunomodulation can stimulate the expression of endogenous HDPs and enhance the body's immune defense, representing a novel non-antibiotic strategy for disease prevention. The project aims to explore the regulatory mechanism of protegrin-1 (PG-1) expression using sodium phenylbutyrate (PBA) by omics sequencing technology and further investigate the role of key regulatory genes on intestinal health. The results showed that PBA promoted PG-1 expression in intestinal epithelial cells based on cell density through epidermal growth factor receptor (EGFR) and G protein-coupled receptor (GPR43). Transcriptome sequencing and microRNA sequencing revealed that C-X-C motif chemokine receptor 2 (CXCR2) exhibited interactions with PG-1. Pre-treatment cells with a CXCR2 inhibitor (SB225002) effectively suppressed the induction of PG-1 by PBA. Furthermore, SB225002 significantly suppressed the gene expression of HDPs in the jejunum of mice without influencing on the morphology, number of goblet cells, and proliferation of the intestine. CXCR2 inhibition significantly reduced the expression of HDPs during E. coli infection, and resulted in the edema of jejunal epithelial cells. The 16S rDNA analysis of cecal contents showed that the E. coli and SB225002 treatments changed gut microbiota diversity and composition at different taxonomic levels. Correlation analysis suggested a potential regulatory relationship between gut microbiota and HDPs. To that end, a gene involved in the HDP expression, CXCR2, has been identified in the study, which contributes to improving intestinal immune function. PBA may be used as a functional additive to regulate intestinal mucosal function, thereby enhancing the health of the intestinal and host.

REGγ Mitigates Radiation-Induced Enteritis by Preserving Mucin Secretion and Sustaining Microbiome Homeostasis

Radiation-induced enteritis, a significant concern in abdominal radiation therapy, is associated closely with gut microbiota dysbiosis. The mucus layer plays a pivotal role in preventing the translocation of commensal and pathogenic microbes. Although significant expression of REGγ in intestinal epithelial cells is well established, its role in modulating the mucus layer and gut microbiota remains unknown. The current study revealed notable changes in gut microorganisms and metabolites in irradiated mice lacking REGγ, as compared to wild-type mice. Concomitant with gut microbiota dysbiosis, REGγ deficiency facilitated the infiltration of neutrophils and macrophages, thereby exacerbating intestinal inflammation after irradiation. Furthermore, fluorescence in situ hybridization assays unveiled an augmented proximity of bacteria to intestinal epithelial cells in REGγ knockout mice after irradiation. Mechanistically, deficiency of REGγ led to diminished goblet cell populations and reduced expression of key goblet cell markers, Muc2 and Tff3, observed in both murine models, minigut organoid systems and human intestinal goblet cells, indicating the intrinsic role of REGγ within goblet cells. Interestingly, although administration of broad-spectrum antibiotics did not alter the goblet cell numbers or mucin 2 (MUC2) secretion, it effectively attenuated inflammation levels in the ileum of irradiated REGγ absent mice, bringing them down to the wild-type levels. Collectively, these findings highlight the contribution of REGγ in counteracting radiation-triggered microbial imbalances and cell-autonomous regulation of mucin secretion.

The in vitro intestinal cell model: different co-cultured cells create different applications

As a vitro absorption model, the Caco-2 cells originate from a human colon adenocarcinomas and can differentiate into a cell layer with enterocyte-like features. The Caco-2 cell model is popularly applied to explore drug transport mechanisms, to evaluate the permeability of drug and to predict the absorption of drugs or bioactive substances in the gut. However, there are limitations to the application of Caco-2 cell model due to lack of a mucus layer, the long culture period and the inability to accurately simulate the intestinal environment. The most frequent way to expand the Caco-2 cell model and address its limitations is by co-culturing it with other cells or substances. This article reviews the culture methods and applications of 3D and 2D co-culture cell models established around Caco-2 cells. It also concludes with a summary of model strengths and weaknesses.

Obeticholic acid attenuates the intestinal barrier disruption in a rat model of short bowel syndrome

BACKGROUND

Short bowel syndrome (SBS) features nutrients malabsorption and impaired intestinal barrier. Patients with SBS are prone to sepsis, intestinal flora dysbiosis and intestinal failure associated liver disease. Protecting intestinal barrier and preventing complications are potential strategies for SBS treatment. This study aims to investigate the effects of farnesoid X receptor (FXR) agonist, obeticholic acid (OCA), have on intestinal barrier and ecological environment in SBS.

METHODS AND RESULTS

Through testing the small intestine and serum samples of patients with SBS, impaired intestinal barrier was verified, as evidenced by reduced expressions of intestinal tight junction proteins (TJPs), increased levels of apoptosis and epithelial cell damage. The intestinal expressions of FXR and related downstream molecules were decreased in SBS patients. Then, global FXR activator OCA was used to further dissect the potential role of the FXR in a rat model of SBS. Low expressions of FXR-related molecules were observed on the small intestine of SBS rats, along with increased proinflammatory factors and damaged barrier function. Furthermore, SBS rats possessed significantly decreased body weight and elevated death rate. Supplementation with OCA mitigated the damaged intestinal barrier and increased proinflammatory factors in SBS rats, accompanied by activated FXR-related molecules. Using 16S rDNA sequencing, the regulatory role of OCA on gut microbiota in SBS rats was witnessed. LPS stimulation to Caco-2 cells induced apoptosis and overexpression of proinflammatory factors in vitro. OCA incubation of LPS-pretreated Caco-2 cells activated FXR-related molecules, increased the expressions of TJPs, ameliorated apoptosis and inhibited overexpression of proinflammatory factors.

CONCLUSIONS

OCA supplementation could effectively ameliorate the intestinal barrier disruption and inhibit overexpression of proinflammatory factors in a rat model of SBS and LPS-pretreated Caco-2 cells. As a selective activator of FXR, OCA might realize its protective function through FXR activation.

Computational insights into colonic motility: Mechanical role of mucus in homeostasis and inflammation

Colonic motility plays a vital role in maintaining proper digestive function. The rhythmic contractions and relaxations facilitate various types of motor functions that generate both propulsive and non-propulsive motility modes which in turn generate shear stresses on the epithelial surface. However, the interplay between colonic mucus, shear stress, and epithelium remains poorly characterized. Here, we present a colonic computational model that describes the potential roles of mucus and shear stress in both homeostasis and ulcerative colitis (UC). Our model integrates several key features, including the properties of the mucus bilayer and faeces, intraluminal pressure, and crypt characteristics to predict the time-space mosaic of shear stress. We show that the mucus thickness which could vary based on the severity of UC, may significantly reduce the amount of shear stress applied to the colonic crypts and effect faecal velocity. Our model also reveals an important spatial shear stress variance in homeostatic colonic crypts that suggests shear stress may have a modulatory role in epithelial cell migration, differentiation, apoptosis, and immune surveillance. Together, our study uncovers the rather neglected roles of mucus and shear stress in intestinal cellular processes during homeostasis and inflammation.

Potential effects and mechanism of flavonoids extract of Callicarpa nudiflora Hook on DSS-induced colitis in mice

Callicarpa nudiflora Hook (C. nudiflora) is an anti-inflammatory, antimicrobial, antioxidant, and hemostatic ethnomedicine. To date, little has been reported regarding the activity of C. nudiflora against ulcerative colitis (UC). In this study, we investigated the effect of a flavonoid extract of C. nudiflora on Dextran Sulfate Sodium (DSS)-induced ulcerative colitis in mice. Mice in the treatment group (CNLF+DSS group) and drug-only (CNLF group) groups were administered 400 mg/kg of flavonoid extract of C. nudiflora leaf (CNLF), and drinking water containing 2.5 % DSS was given to the model and treatment groups. The symptoms of colitis were detected, relevant indicators were verified, intestinal barrier function was assessed, and the contents of the cecum were analyzed for intestinal microorganisms. The results showed that CNLF significantly alleviated the clinical symptoms and histological morphology of colitis in mice, inhibited the increase in pro-inflammatory factors (TNF-α, IL-6, IL-1β, and IFN-γ), and increased the level of IL-10. The expression of NF-κB and MAPK inflammatory signal pathway-related proteins (p-p65, p-p38, p-ERK, p-JNK) was regulated. The expression of tight junction proteins (ZO-1, OCLDN, and CLDN1) was increased, while the content of D-LA, DAO, and LPS was decreased. In addition, 16S rRNA sequencing showed that CNLF restored the gut microbial composition, and increased the relative abundance of Prevotellaceae, Intestinimonas butyriciproducens, and Barnesiella_intestinihominis. In conclusion, CNLF alleviated colitis by suppressing inflammation levels, improving intestinal barrier integrity, and modulating the intestinal microbiota, and therefore has promising future applications in the treatment of UC.

Astragalus polysaccharides attenuate chemotherapy-induced immune injury by modulating gut microbiota and polyunsaturated fatty acid metabolism

BACKGROUND

The damage of chemotherapy drugs to immune function and intestinal mucosa is a common side effect during chemotherapy. Astragalus polysaccharides (APS) exhibit immunomodulatory properties and are recognized for preserving the integrity of the human intestinal barrier. Nevertheless, their application and mechanisms of action in chemotherapy-induced immune damage and intestinal barrier disruption remain insufficiently explored.

PURPOSE

This study delved into investigating how APS mitigates chemotherapy-induced immune dysfunction and intestinal mucosal injury, while also providing deeper insights into the underlying mechanisms.

METHODS

In a chemotherapy mice model induced by 5-fluorouracil (5-Fu), the assessment of APS's efficacy encompassed evaluations of immune organ weight, body weight, colon length, and histopathology. The regulation of different immune cells in spleen was detected by flow cytometry. 16S rRNA gene sequencings, ex vivo microbiome assay, fecal microbiota transplantation (FMT), and targeted metabolomics analysis were applied to explore the mechanisms of APS effected on chemotherapy-induced mice.

RESULTS

APS ameliorated chemotherapy-induced damage to immune organs and regulated immune cell differentiation disorders, including CD4+T, CD8+T, CD19+B, F4/80+CD11B+ macrophages. APS also alleviated colon shortening and upregulated the expression of intestinal barrier proteins. Furthermore, APS significantly restored structure of gut microbiota following chemotherapy intervention. Ex vivo microbiome assays further demonstrated the capacity of APS to improve 5-Fu-induced microbiota growth inhibition and compositional change. FMT demonstrated that the regulation of gut microbiota by APS could promote the recovery of immune functions and alleviate shortening of the colon length. Remarkably, APS significantly ameliorated the imbalance of linoleic acid (LA) and α-linolenic acid in polyunsaturated fatty acid (PUFA) metabolism. Further in vitro experiments showed that LA could promote splenic lymphocyte proliferation. In addition, both LA and DGLA down-regulated the secretion of NO and partially up-regulated the percentage of F4/80+CD11B+CD206+ cells.

CONCLUSION

APS can effectively ameliorate chemotherapy-induced immune damage and intestinal mucosal disruption by regulating the composition of the gut microbiota and further restoring PUFA metabolism. These findings indicate that APS can serve as an adjuvant to improve the side effects such as intestinal and immune damage caused by chemotherapy.

Tributyltin (TBT) toxicity: Effects on enteric neuronal plasticity and intestinal barrier of rats' duodenum

Tributyltin (TBT) is a biocide used in the formulation of antifouling paints and it is highly harmful. Despite the ban, the compound persists in the environment, contaminating marine foodstuffs and household products. Therefore, considering the route of exposure to the contaminant, the gastrointestinal tract (GIT) acts as an important barrier against harmful substances and is a potential biomarker for understanding the consequences of these agents. This work aimed to evaluate histological and neuronal alterations in the duodenum of male Wistar rats that received 20 ng/g TBT and 600 ng/g via gavage for 30 consecutive days. After the experimental period, the animals were euthanized, and the duodenum was intended for neuronal histochemistry (total and metabolically active populations) and histological routine (morphometry and histopathology). The results showed more severe changes in neuronal density and intestinal morphometry in rats exposed to 20 ng/g, such as total neuronal density decrease and reduction of intestinal layers. In rats exposed to 600 ng/g of TBT, it was possible to observe only an increase in intraepithelial lymphocytes. We conclude that TBT can be more harmful to intestinal homeostasis when consumed in lower concentrations.

Taurine Alleviates Experimental Colitis by Enhancing Intestinal Barrier Function and Inhibiting Inflammatory Response through TLR4/NF-κB Signaling

Taurine (Tau) is a semiessential amino acid in mammals with preventive and therapeutic effects on several intestinal disorders. However, the exact function of taurine in ulcerative colitis (UC) is still largely unclear. In this study, we used two taurine-deficient mouse models (CSAD-/- and TauT-/- mice) to explore the influence of taurine on the progression of UC in both dextran sulfate sodium (DSS)-induced colitis and LPS-stimulated Caco-2 cells. We found that cysteine sulfinic acid decarboxylase (CSAD) and taurine transporter (TauT) expressions and taurine levels were markedly reduced in colonic tissues of mice treated with DSS. The CSAD and TauT knockouts exacerbated DSS-induced clinical symptoms and pathological damage and aggravated the intestinal barrier dysfunction and the colonic mucosal inflammatory response. Conversely, taurine pretreatment enhanced the intestinal barrier functions by increasing goblet cells and upregulating tight junction protein expression. Importantly, taurine bound with TLR4 and inhibited the TLR4/NF-κB pathway, ultimately reducing proinflammatory factors (TNF-α and IL-6) and oxidative stress. Our findings highlight the essential role of taurine in maintaining the intestinal barrier integrity and inhibiting intestinal inflammation, indicating that taurine is a promising supplement for colitis treatment.

Biochanin a ameliorates DSS-induced ulcerative colitis by improving colonic barrier function and protects against the development of spontaneous colitis in the Muc2 deficient mice

There is an increasing appreciation that colonic barrier function is closely related to the development and progression of colitis. The mucus layer is a crucial component of the colonic barrier, responsible for preventing harmful bacteria from invading the intestinal epithelium and causing inflammation. Furthermore, a defective mucus barrier is also a significant characteristic of ulcerative colitis (UC). Biochanin A (BCA), an isoflavonoid, has garnered increasing interest due to its significant biological activities. However, the impact of BCA on UC has not been reported yet. In this study, we used a dextran sodium sulfate (DSS)-induced ulcerative colitis model and the Muc2 deficient (Muc2-/-) mice spontaneous colitis model to explore the mechanisms of BCA in the treatment of UC. Here, we verified that DSS-induced UC was observably attenuated and spontaneous colitis in Muc2-/- mice was relieved by BCA. Treatment with BCA improved colitis-related symptoms and reduced intestinal permeability by upregulating the levels of goblet cells and tight junction (TJ) proteins. In addition, we confirmed that BCA promotes autophagy through the AMP-activated protein kinase (AMPK)/mammalian target of rapamycin (mTOR)/Unc-51-like kinase 1 (ULK1) pathway, thereby alleviating DSS-induced UC. In addition, the administration of BCA was able to reduce apoptosis and promote proliferation by suppressing Cleaved Caspase-3 (Cleaved Cas-3) expression, and increasing PCNA and Ki67 levels. Further research revealed that BCA treatment ameliorated spontaneous colitis and alleviated epithelial damage in Muc2-/- mice by restoring the intestinal barrier and promoting autophagy. Our results demonstrated that BCA alleviated UC by enhancing intestinal barrier function and promoting autophagy. These findings indicate that BCA may be a novel treatment alternative for UC.

Mucin alleviates colonic barrier dysfunction by promoting spermine accumulation through enhanced arginine metabolism in Limosilactobacillus mucosae

Dietary fiber deprivation is linked to probiotic extinction, mucus barrier dysbiosis, and the overgrowth of mucin-degrading bacteria. However, whether and how mucin could rescue fiber deprivation-induced intestinal barrier defects remains largely unexplored. Here, we sought to investigate the potential role and mechanism by which exogenous mucin maintains the gut barrier function. The results showed that dietary mucin alleviated fiber deprivation-induced disruption of colonic barrier integrity and reduced spermine production in vivo. Importantly, we highlighted that microbial-derived spermine production, but not host-produced spermine, increased significantly after mucin supplementation, with a positive association with upgraded colonic Lactobacillus abundance. After employing an in vitro model, the microbial-derived spermine was consistently dominated by both mucin and Lactobacillus spp. Furthermore, Limosilactobacillus mucosae was identified as an essential spermine-producing Lactobacillus spp., and this isolated strain was responsible for spermine accumulation, especially after adhering to mucin in vitro. Specifically, the mucin-supplemented bacterial supernatant of Limosilactobacillus mucosae was verified to promote intestinal barrier functions through the increased spermine production with a dependence on enhanced arginine metabolism. Overall, these findings collectively provide evidence that mucin-modulated microbial arginine metabolism bridged the interplay between microbes and gut barrier function, illustrating possible implications for host gut health.

IMPORTANCE

Microbial metabolites like short-chain fatty acids produced by dietary fiber fermentation have been demonstrated to have beneficial effects on intestinal health. However, it is essential to acknowledge that certain amino acids entering the colon can be metabolized by microorganisms to produce polyamines. The polyamines can promote the renewal of intestinal epithelial cell and maintain host-microbe homeostasis. Our study highlighted the specific enrichment by mucin on promoting the arginine metabolism in Limosilactobacillus mucosae to produce spermine, suggesting that microbial-derived polyamines support a significant enhancement on the goblet cell proliferation and barrier function.

Gut microbiota as a key regulator of intestinal mucosal immunity

Gut microbiota is a complex microbial community with the ability of maintaining intestinal health. Intestinal homeostasis largely depends on the mucosal immune system to defense external pathogens and promote tissue repair. In recent years, growing evidence revealed the importance of gut microbiota in shaping intestinal mucosal immunity. Therefore, according to the existing findings, this review first provided an overview of intestinal mucosal immune system before summarizing the regulatory roles of gut microbiota in intestinal innate and adaptive immunity. Specifically, this review delved into the gut microbial interactions with the cells such as intestinal epithelial cells (IECs), macrophages, dendritic cells (DCs), neutrophils, and innate lymphoid cells (ILCs) in innate immunity, and T and B lymphocytes in adaptive immunity. Furthermore, this review discussed the main effects of gut microbiota dysbiosis in intestinal diseases and offered future research prospects. The review highlighted the key regulatory roles of gut microbiota in intestinal mucosal immunity via various host-microbe interactions, providing valuable references for the development of microbial therapy in intestinal diseases.

Effects of the plastic additive 2,4-di-tert-butylphenol on intestinal microbiota of zebrafish

Plastic additives such as the antioxidant 2,4-di-tert-butylphenol (2,4-DTBP) have been widely detected in aquatic environments, over a wide range of concentrations reaching 300 μg/L in surface water, potentially threatening the health of aquatic organisms and ecosystems. However, knowledge of the specific effects of 2,4-DTBP on aquatic vertebrates is still limited. In this study, adult zebrafish were exposed to different concentrations of 2,4-DTBP (0, 0.01, 0.1 and 1.0 mg/L) for 21 days in the laboratory. The amplicon sequencing results indicated that the diversity and composition of the zebrafish gut microbiota were significantly changed by 2,4-DTBP, with a shift in the dominant flora to more pathogenic genera. Exposure to 2,4-DTBP at 0.1 and 1.0 mg/L significantly increased the body weight and length of zebrafish, suggesting a biological stress response. Structural assembly defects were also observed in the intestinal tissues of zebrafish exposed to 2,4-DTBP, including autolysis of intestinal villi, adhesions and epithelial detachment of intestinal villi, as well as inflammation. The transcriptional expression of some genes showed that 2,4-DTBP adversely affected protein digestion and absorption, glucose metabolism and lipid metabolism. These results are consistent with the PICRUSt2 functional prediction analysis of intestinal microbiota of zebrafish exposed to 2,4-DTBP. This study improves our understanding of the effects of 2,4-DTBP on the health of aquatic vertebrates and ecosystems.

Epithelial-neuronal-immune cell interactions: Implications for immunity, inflammation, and tissue homeostasis at mucosal sites

The epithelial lining of the respiratory tract and intestine provides a critical physical barrier to protect host tissues against environmental insults, including dietary antigens, allergens, chemicals, and microorganisms. In addition, specialized epithelial cells communicate directly with hematopoietic and neuronal cells. These epithelial-immune and epithelial-neuronal interactions control host immune responses and have important implications for inflammatory conditions associated with defects in the epithelial barrier, including asthma, allergy, and inflammatory bowel diseases. In this review, we discuss emerging research that identifies the mechanisms and impact of epithelial-immune and epithelial-neuronal cross talk in regulating immunity, inflammation, and tissue homeostasis at mucosal barrier surfaces. Understanding the regulation and impact of these pathways could provide new therapeutic targets for inflammatory diseases at mucosal sites.

Hepatic injury and ileitis associated with gut microbiota dysbiosis in mice upon F-53B exposure

Chlorinated polyfluorinated ether sulfonate (F-53B), a substitute of perfluorooctane sulfonic acid (PFOS), has attracted significant attention for its link to hepatotoxicity and enterotoxicity. Nevertheless, the underlying mechanisms of F-53B-induced enterohepatic toxicity remain incompletely understood. This study aimed to explore the role of F-53B exposure on enterohepatic injury based on the gut microbiota, pathological and molecular analysis in mice. Here, we exposed C57BL/6 mice to F-53B (0, 4, 40, and 400 μg/L) for 28 days. Our findings revealed a significant accumulation of F-53B in the liver, followed by small intestines, and feces. In addition, F-53B induced pathological collagen fiber deposition and lipoid degeneration, up-regulated the expression of fatty acid β-oxidation-related genes (PPARα and PPARγ, etc), while simultaneously down-regulating pro-inflammatory genes (Nlrp3, IL-1β, and Mcp1) in the liver. Meanwhile, F-53B induced ileal mucosal barrier damage, and an up-regulation of pro-inflammatory genes and mucosal barrier-related genes (Muc1, Muc2, Claudin1, Occludin, Mct1, and ZO-1) in the ileum. Importantly, F-53B distinctly altered gut microbiota compositions by increasing the abundance of Akkermansia and decreasing the abundance of Prevotellaceae_NK3B31_group in the feces. F-53B-altered microbiota compositions were significantly associated with genes related to fatty acid β-oxidation, inflammation, and mucosal barrier. In summary, our results demonstrate that F-53B is capable of inducing hepatic injury, ileitis, and gut microbiota dysbiosis in mice, and the gut microbiota dysbiosis may play an important role in the F-53B-induced enterohepatic toxicity.

Coarse-grained modeling and dynamics tracking of nanoparticles diffusion in human gut mucus

The gastrointestinal (GI) tract's mucus layer serves as a critical barrier and a mediator in drug nanoparticle delivery. The mucus layer's diverse molecular structures and spatial complexity complicates the mechanistic study of the diffusion dynamics of particulate materials. In response, we developed a bi-component coarse-grained mucus model, specifically tailored for the colorectal cancer environment, that contained the two most abundant glycoproteins in GI mucus: Muc2 and Muc5AC. This model demonstrated the effects of molecular composition and concentration on mucus pore size, a key determinant in the permeability of nanoparticles. Using this computational model, we investigated the diffusion rate of polyethylene glycol (PEG) coated nanoparticles, a widely used muco-penetrating nanoparticle. We validated our model with experimentally characterized mucus pore sizes and the diffusional coefficients of PEG-coated nanoparticles in the mucus collected from cultured human colorectal goblet cells. Machine learning fingerprints were then employed to provide a mechanistic understanding of nanoparticle diffusional behavior. We found that larger nanoparticles tended to be trapped in mucus over longer durations but exhibited more ballistic diffusion over shorter time spans. Through these discoveries, our model provides a promising platform to study pharmacokinetics in the GI mucus layer.

Resveratrol-loaded pH-responsive Mesona chinensis polysaccharides-zein nanoparticles for effective treatment of ulcerative colitis

BACKGROUND

Resveratrol (Res) is promising food functional factor with favorable antioxidant and anti-inflammatory properties, although its poor water solubility and low bioavailability limit extensive application. Therefore, in combination with another promising polysaccharide (Mesona chinensis polysaccharides, MCP), Res-loaded food nanocarriers (ResNPs) were developed to increase its water solubility, bioactivity and targeting properties. ResNPs were then applied to alleviate dextran sulfate sodium (DSS)-induced ulcerative colitis.

RESULTS

Resveratrol can be well encapsulated in MCP-based nanoparticles in an amorphous state, improving its water solubility. ResNPs showed pH-response controlled release behavior in the gastrointestinal tract and increased the enrichment of Res in the colon. In vivo experiments of ResNPs against DSS-induced ulcerative colitis (UC) revealed that ResNPs significantly improved UC symptoms, modulated intestinal inflammation and down-regulated oxidative stress levels compared to free Res. ResNPs also play an positive role with respect to inhibiting the mitogen-activated protein kinase pathway and promoting the expression of tight junction proteins. In addition, ResNPs improved the species composition and relative abundance of intestinal flora in UC mice, which effectively regulated the balance of intestinal flora and promoted the production of short-chain fatty acids.

CONCLUSION

These results suggest that MCP-based nanoparticles can effectively improve the solubility of resveratrol and enhance its in vivo bioactivity. Moreover, the present study also provides a new strategy for the prevention and treatment of UC with food polyphenol. © 2024 Society of Chemical Industry.

Sea Buckthorn Polysaccharide Ameliorates Colitis

Ulcerative colitis (UC) is characterized by chronic inflammation and ulceration of the intestinal inner lining, resulting in various symptoms. Sea buckthorn berries contain a bioactive compound known as sea buckthorn polysaccharide (SBP). However, the precise mechanisms underlying the impact of SBP on UC remain unclear. In this study, we investigated the effects of pretreatment with SBP on colitis induced by DSS. Our findings demonstrate that SBP pretreatment effectively reduces inflammation, oxidative stress, and intestinal barrier damage associated with colitis. To further elucidate the role of SBP-modulated gut microbiota in UC, we performed fecal microbiota transplantation (FMT) on DSS-treated mice. The microbiota from SBP-treated mice exhibits notable anti-inflammatory and antioxidant effects, improves colonic barrier integrity, and increases the abundance of beneficial bacteria, as well as enhancing SCFA production. Collectively, these results strongly indicate that SBP-mediated amelioration of colitis is attributed to its impact on the gut microbiota, particularly through the promotion of SCFA-producing bacteria and subsequent elevation of SCFA levels. This study provides compelling evidence supporting the efficacy of pre-emptive SBP supplementation in alleviating colitis symptoms by modulating the gut microbiota, thereby offering novel insights into the potential of SBP as a regulator of the gut microbiota for colitis relief.

An enteric ultrastructural surface atlas of the model insect Manducasexta

The tobacco hornworm is a laboratory model that is particularly suitable for analyzing gut inflammation, but a physiological reference standard is currently unavailable. Here, we present a surface atlas of the healthy hornworm gut generated by scanning electron microscopy and nano-computed tomography. This comprehensive overview of the gut surface reveals morphological differences between the anterior, middle, and posterior midgut, allowing the screening of aberrant gut phenotypes while accommodating normal physiological variations. We estimated a total resorptive midgut surface of 0.42 m2 for L5d6 larvae, revealing its remarkable size. Our data will support allometric scaling and dose conversion from Manduca sexta to mammals in preclinical research, embracing the 3R principles. We also observed non-uniform gut colonization by enterococci, characterized by dense biofilms in the pyloric cone and downstream of the pylorus associated with pore and spine structures in the hindgut intima, indicating a putative immunosurveillance function in the lepidopteran hindgut.

Phosphatidylethanolamine Improves Postnatal Growth Retardation by Regulating Mucus Secretion of Intestinal Goblet Cells in Piglets

Phosphatidylethanolamine (PE), a multifunctional phospholipid, is necessary for neonate development. This study aimed to explore the impact of the regulation of exogenous PE on postnatal growth retardation (PGR) by improving intestinal barrier function. Thirty-two neonatal pigs were divided into four groups according to their body weight (BW 2.79 ± 0.50 kg or 1.88 ± 0.40 kg) at 7 days old, CON-NBW, PE-NBW, CON-PGR, and PE-PGR. PE was supplemented to NBW piglets and PGR piglets during lactation and post-weaning periods. Compared with the NBW piglets, the growth performance of PGR piglets was lower, while PE improved the poor growth performance. PGR piglets showed injured intestinal morphology, as evidenced by the reduced ratio of villus height to crypt depth (VH/CD) and goblet cell numbers in the jejunum and ileum. PE recovered the intestinal barrier injury by increasing VH/CD and goblet cell numbers. The decreased MUC2 mRNA and protein expressions were observed in the small intestine of PGR piglets, and PE remarkably increased the expression of MUC2. Mechanistically, PE increased the goblet cell differentiation promoting gene spdef mRNA levels and reduced the mRNA expressions involved in endoplasmic reticulum stress in the jejunal and ileal mucosa of PGR piglets. Overall, we found that PE alleviated growth retardation by regulating intestinal health and generalized its application in neonates.

Intestinal Mucosal Immune Barrier: A Powerful Firewall Against Severe Acute Pancreatitis-Associated Acute Lung Injury via the Gut-Lung Axis

The pathogenesis of severe acute pancreatitis-associated acute lung injury (SAP-ALI), which is the leading cause of mortality among hospitalized patients in the intensive care unit, remains incompletely elucidated. The intestinal mucosal immune barrier is a crucial component of the intestinal epithelial barrier, and its aberrant activation contributes to the induction of sustained pro-inflammatory immune responses, paradoxical intercellular communication, and bacterial translocation. In this review, we firstly provide a comprehensive overview of the composition of the intestinal mucosal immune barrier and its pivotal roles in the pathogenesis of SAP-ALI. Secondly, the mechanisms of its crosstalk with gut microbiota, which is called gut-lung axis, and its effect on SAP-ALI were summarized. Finally, a number of drugs that could enhance the intestinal mucosal immune barrier and exhibit potential anti-SAP-ALI activities were presented, including probiotics, glutamine, enteral nutrition, and traditional Chinese medicine (TCM). The aim is to offer a theoretical framework based on the perspective of the intestinal mucosal immune barrier to protect against SAP-ALI.

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.

The effect of lentinan on dexamethasone-induced immunosuppression in mice

The immune system acts as a vital defense barrier against pathogenic invasions, and its stable operation is crucial for maintaining body health. Nevertheless, various natural or artificial factors can compromise the body's immune function, leading to immunosuppression, which may interfere with the efficacy of vaccination and increase the susceptibility of the body to disease-causing pathogens. In an effort to ensure successful vaccinations and improve overall physical well-being, the search for appropriate immune regulators to enhance immunity is of paramount importance. Lentinan (LNT) has a significant role in immune regulation and vaccine adjuvants. In the present study, we constructed an immunosuppressive model using dexamethasone (DEX) and demonstrated that LNT could significantly improved antibody levels in immunosuppressive mice and stimulated T-lymphocyte proliferation and differentiation in intestinal Peyer's patches. LNT also increased the production of secretory immunoglobulin A (sIgA) in the duodenal fluid, the number of goblet cells, and the proportion of mucin area. Moreover, LNT modulated the intestinal microbiota and increased the production of short-chain fatty acids. Additionally, LNT promoted the proliferation, differentiation, and pro-inflammatory cytokines production of DEX-treated splenic T lymphocytes in vitro. Thus, the present study highlights the potential of LNT in reversing immunosuppression and avoiding the failure of vaccination.

Neonatal intestinal mucus barrier changes in response to maturity, inflammation, and sodium decanoate supplementation

The integrity of the intestinal mucus barrier is crucial for human health, as it serves as the body's first line of defense against pathogens. However, postnatal development of the mucus barrier and interactions between maturity and its ability to adapt to external challenges in neonatal infants remain unclear. In this study, we unveil a distinct developmental trajectory of the mucus barrier in preterm piglets, leading to enhanced mucus microstructure and reduced mucus diffusivity compared to term piglets. Notably, we found that necrotizing enterocolitis (NEC) is associated with increased mucus diffusivity of our large pathogen model compound, establishing a direct link between the NEC condition and the mucus barrier. Furthermore, we observed that addition of sodium decanoate had varying effects on mucus diffusivity depending on maturity and health state of the piglets. These findings demonstrate that regulatory mechanisms governing the neonatal mucosal barrier are highly complex and are influenced by age, maturity, and health conditions. Therefore, our results highlight the need for specific therapeutic strategies tailored to each neonatal period to ensure optimal gut health.

Transient Mild Photothermia Improves Therapeutic Performance of Oral Nanomedicines with Enhanced Accumulation in the Colitis Mucosa

The treatment outcomes of oral medications against ulcerative colitis (UC) have long been restricted by low drug accumulation in the colitis mucosa and subsequent unsatisfactory therapeutic efficacy. Here, high-performance pluronic F127 (P127)-modified gold shell (AuS)-polymeric core nanotherapeutics loading with curcumin (CUR) is constructed. Under near-infrared irradiation, the resultant P127-AuS@CURs generate transient mild photothermia (TMP; ≈42 °C, 10 min), which facilitates their penetration through colonic mucus and favors multiple cellular processes, including cell internalization, lysosomal escape, and controlled CUR release. This strategy relieves intracellular oxidative stress, improves wound healing, and reduces immune responses by polarizing the proinflammatory M1-type macrophages to the anti-inflammatory M2-type. Upon oral administration of hydrogel-encapsulating P127-AuS@CURs plus intestinal intralumen TMP, their therapeutic effects against acute and chronic UC are demonstrated to be superior to those of a widely used clinical drug, dexamethasone. The treatment of P127-AuS@CURs (+ TMP) elevates the proportions of beneficial bacteria (e.g., Lactobacillus and Lachnospiraceae), whose metabolites can also mitigate colitis symptoms by regulating genes associated with antioxidation, anti-inflammation, and wound healing. Overall, the intestinal intralumen TMP offers a promising approach to enhance the therapeutic outcomes of noninvasive medicines against UC.

Effects of probiotic supplementation on chronic inflammatory process modulation in colorectal carcinogenesis

The current study investigated the potential effects of probiotic supplementation on colorectal carcinogenesis chemically induced with 1,2-dimethylhydrazine (DMH) and treated with 5-fluorouracil (5FU)-based chemotherapy in mice. Animals were randomly allocated in five different groups: Control: which not receive any treatment throughout the experimental course; Colitis model group (DMH): treated with DMH; DMH+ 5FU: animals received I.P. (intraperitoneal) dose of chemotherapy on a weekly basis; DMH+PROB: animals received daily administrations (via gavage) of probiotics (Lactobacillus: acidophilus and paracasei, Bifidobacterium lactis and bifidum); and DMH+ PROB+ 5FU: animals received the same treatment as the previous groups. After ten-week treatment, mice's large intestine was collected and subjected to colon length, histopathological, periodic acid-schiff (PAS) staining and immunohistochemistry (TLR2, MyD88, NF-κB, IL-6, TLR4, TRIF, IRF-3, IFN-γ, Ki-67, KRAS, p53, IL-10, and TGF-β) analyzes. Variance (ANOVA) and Kruskal-Wallis tests were used for statistical analysis, at significance level p 0.05. Probiotics' supplementation has increased the production of Ki-67 cell-proliferation marker, reduced body weight, and colon shortening, as well as modulated the chronic inflammatory process in colorectal carcinogenesis by inhibiting NF-κB expression and mitigating mucin depletion. Thus, these findings lay a basis for guide future studies focused on probiotics' action mechanisms in tumor microenvironment which might have implications in clinical practice.

The role of goblet cells in Crohn' s disease

The prevalence of Crohn's disease (CD), a subtype of inflammatory bowel disease (IBD), is increasing worldwide. The pathogenesis of CD is hypothesized to be related to environmental, genetic, immunological, and bacterial factors. Current studies have indicated that intestinal epithelial cells, including columnar, Paneth, M, tuft, and goblet cells dysfunctions, are strongly associated with these pathogenic factors. In particular, goblet cells dysfunctions have been shown to be related to CD pathogenesis by direct or indirect ways, according to the emerging studies. The mucus barrier was established with the help of mucins secreted by goblet cells. Not only do the mucins mediate the mucus barrier permeability and bacterium selection, but also, they are closely linked with the endothelial reticulum stress during the synthesis process. Goblet cells also play a vital role in immune response. It was indicated that goblet cells take part in the antigen presentation and cytokines secretion process. Disrupted goblet cells related immune process were widely discovered in CD patients. Meanwhile, dysbiosis of commensal and pathogenic microbiota can induce myriad immune responses through mucus and goblet cell-associated antigen passage. Microbiome dysbiosis lead to inflammatory reaction against pathogenic bacteria and abnormal tolerogenic response. All these three pathways, including the loss of mucus barrier function, abnormal immune reaction, and microbiome dysbiosis, may have independent or cooperative effect on the CD pathogenesis. However, many of the specific mechanisms underlying these pathways remain unclear. Based on the current understandings of goblet cell's role in CD pathogenesis, substances including butyrate, PPARγagonist, Farnesoid X receptor agonist, nuclear factor-Kappa B, nitrate, cytokines mediators, dietary and nutrient therapies were all found to have potential therapeutic effects on CD by regulating the goblet cells mediated pathways. Several monoclonal antibodies already in use for the treatment of CD in the clinical settings were also found to have some goblet cells related therapeutic targets. In this review, we introduce the disease-related functions of goblet cells, their relationship with CD, their possible mechanisms, and current CD treatments targeting goblet cells.

Qingchang Wenzhong Decoction ameliorates intestinal inflammation and intestinal barrier dysfunction in ulcerative colitis via the GC-C signaling pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Ulcerative colitis (UC) is an idiopathic, chronic inflammatory disorder of the colonic mucosa, accompanied with abdominal pain, and bloody diarrhea. Currently, clinical treatment options for UC are limited. Qingchang Wenzhong Decoction (QCWZD) is an effective prescription of traditional Chinese medicine for the treatment of UC. However, the mechanism of QCWZD in alleviating intestinal barrier dysfunction in UC has not been clearly explained.

AIM OF THE STUDY

To determine the mechanism whereby QCWZD promotes the recovery of intestinal barrier dysfunction in UC.

MATERIALS AND METHODS

A secondary analysis of colonic mucosa from UC patients acquired from a prior RCT clinical trial was performed. The effects of QCWZD on intestinal mucus and mechanical barriers in UC patients were evaluated using colon tissue paraffin-embedded sections from UC patients. The mechanism was further investigated by in vivo and in vitro experiments. UC mice were established in sterile water with 3.0% dextran sodium sulfate (DSS). Meanwhile, mice in the treatment group were dosed with QCWZD or mesalazine. In vitro, an intestinal barrier model was constructed using Caco-2 and HT29 cells in co-culture. GC-C plasmid was used to overexpress/knock down GC-C to clarify the target of QCWZD. HE, AB-PAS, ELISA, immunohistochemistry and immunofluorescence assays were used to assess the level of colonic inflammation and intestinal barrier integrity. Rt-qPCR, Western Blot were used to detect the expression of genes and proteins related to GC-C signaling pathway. Molecular docking was used to simulate the binding sites of major components of QCWZD to GC-C.

RESULTS

In UC patients, QCWZD increased mucus secretion, goblet cell number, and promoted MUC2 and ZO-1 expression. QCWZD accelerated the recovery of UC mice from DSS-induced inflammation, including weight gain, reduced disease activity index (DAI) scores, colon length recovery, and histological healing. QCWZD promoted mucus secretion and increased ZO-1 expression in in vivo and in vitro experiments, thereby repairing mucus mechanical barrier damage. The effects of QCWZD are mediated through regulation of the GC-C signaling pathway, which in turn affects CFTR phosphorylation and MUC2 expression to promote mucus secretion, while inhibiting the over-activation of MLCK and repairing tight junctions to maintain the integrity of the mechanical barrier. Molecular docking results demonstrate the binding of the main components of QCWZD to GC-C.

CONCLUSION

Our study demonstrated that QCWZD modulates the GC-C signaling pathway to promote remission of mucus-mechanical barrier damage in the UC. The clarification of the mechanism of QCWZD holds promise for the development of new therapies for UC.

Time-dependent impact of a high-fat diet on the intestinal barrier of male mice

BACKGROUND

Excessive saturated fat intake compromises the integrity of the intestinal mucosa, leading to low-grade inflammation, impaired mucosal integrity, and increased intestinal permeability, resulting in the migration of lipopolysaccharide (LPS) to other tissues.

AIM

To evaluate the chronic effects (at 10 and 16 wk) of a high-fat diet (HFD) (with 50% energy as fat) on the phylogenetic gut microbiota distribution and intestinal barrier structure and protection in C57BL/6 mice.

METHODS

Forty adult male mice were divided into four nutritional groups, where the letters refer to the type of diet (control and HFD or HF) and the numbers refer to the period (in weeks) of diet administration: Control diet for 10 wk, HFD for 10 wk, control diet for 16 wk, and HFD for 16 wk. After sacrifice, biochemical, molecular, and stereological analyses were performed.

RESULTS

The HF groups were overweight, had gut dysbiosis, had a progressive decrease in occludin immunostaining, and had increased LPS concentrations. Dietary progression reduced the number of goblet cells per large intestine area and Mucin2 expression in the HF16 group, consistent with a completely disarranged intestinal ultrastructure after 16 wk of HFD intake.

CONCLUSION

Chronic HFD intake causes overweight, gut dysbiosis, and morphological and functional alterations of the intestinal barrier after 10 or 16 wk. Time-dependent reductions in goblet cell numerical density and mucus production have emerged as targets for countering obesity-driven intestinal damage.

The protective effect of L-theanine on the intestinal barrier in heat-stressed organisms

Heat stress caused by heatwaves, extreme temperatures, and other weather can damage the intestinal barrier of organisms. L-Theanine (LTA) attenuates heat stress-induced oxidative stress, inflammatory responses, and impaired immune function, but its protective effect on the intestinal barrier of heat-stressed organisms is unclear. In this study, low (100 mg kg-1 d-1), medium (200 mg kg-1 d-1), and high (400 mg kg-1 d-1) dosages of LTA were used in the gavage of C57BL/6J male mice that were experimented on for 50 d. These mice were subjected to heat stress for 2 h d-1 at 40 ± 1 °C and 60 ± 5% RH in the last 7 d. LTA attenuated the heat stress-induced decreases in body mass and feed intake, and the destruction of intestinal villi and crypt depth; reduced the serum levels of FITC-dextran and D-LA, as well as the DAO activity; and upregulated the colonic tissues of Occludin, Claudin-1, and ZO-1 mRNA and occludin protein expression. The number of goblet cells in the colon tissue of heat-stressed organisms increased in the presence of LTA, and the expression levels of Muc2, Muc4 mRNA, and Muc2 protein were upregulated. LTA increased the abundance of Bifidobacterium and Turicibacter, and decreased the abundance of Enterorhabdus and Desulfovibrio in the intestinal tract of heat-stressed organisms and restored gut microbiota homeostasis. LTA promoted the secretion of IL-4, IL-10, and sIgA and inhibited the secretion of TNF-α and IFN-γ in the colon of heat-stressed organisms. The expressions of Hsf1, Hsp70, Hsph1, TLR4, P38 MAPK, p-P65 NF-κB, MLCK mRNA, and proteins were downregulated by LTA in the colon of heat-stressed organisms. These results suggest that LTA protects the intestinal barrier in heat-stressed organisms by modulating multiple molecular pathways. Therefore, this study provides evidence on how tea-containing LTA treatments could be used to prevent and relieve intestinal problems related to heat stress.

β-Nicotinamide mononucleotide supplementation prolongs the lifespan of prematurely aged mice and protects colon function in ageing mice

Ageing is defined as the degeneration of physiological functions in numerous tissues and organs of an organism, which occurs with age. As we age, the gut undergoes a series of changes and weaknesses that may contribute to overall ageing. Emerging evidence suggests that β-nicotinamide mononucleotide (NMN) plays a role in regulating intestinal function, but there is still a lack of literature on its role in maintaining the colon health of ageing mice. In our research, Zmpste24-/- mice proved that NMN prolonged their life span and delayed senescence. This study was designed to investigate the effects of long-term intervention on regulating colon function in ageing mice. Our results indicated that NMN improved the pathology of intestinal epithelial cells and intestinal permeability by upregulating the expression of intestinal tight junction proteins and the number of goblet cells, increasing the release of anti-inflammatory factors, and increasing beneficial intestinal bacteria. NMN increased the expression of the proteins SIRT1, NMNAT2, and NMNAT3 and decreased the expression of the protein P53. It also regulated the activity of ISCs by increasing Wnt/β-catenin and Lgr5. Our findings also revealed that NMN caused a significant increase in the relative abundance of Akkermansia muciniphila and Bifidobacterium pseudolongum and notable differences in metabolic pathways related to choline metabolism in cancer. In summary, NMN supplementation can delay frailty in old age, aid healthy ageing, and delay gut ageing.

Eugenol Possesses Colitis Protective Effects: Impacts on the TLR4/MyD88/NF-[Formula: see text]B Pathway, Intestinal Epithelial Barrier, and Macrophage Polarization

Eugenol (EU) has been shown to ameliorate experimental colitis due to its anti-oxidant and anti-inflammatory bioactivities. In this study, DSS-induced acute colitis was established and applied to clarify the regulation efficacy of EU on intestinal barrier impairment and macrophage polarization imbalance along with the inflammatory response. Besides, the adjusting effect of EU on macrophages was further investigated in vitro. The results confirmed that EU intervention alleviated DSS-induced colitis through methods such as restraining weight loss and colonic shortening and decreasing DAI scores. Microscopic observation manifested that EU maintained the intestinal barrier integrity in line with the mucus barrier and tight junction protection. Furthermore, EU intervention significantly suppressed the activation of TLR4/MyD88/NF-[Formula: see text]B signaling pathways and pro-inflammatory cytokines gene expressions, while enhancing the expressions of anti-inflammatory cytokines. Simultaneously, WB and FCM analyses of the CD86 and CD206 showed that EU could regulate the DSS-induced macrophage polarization imbalance. Overall, our data further elucidated the mechanism of EU's defensive effect on experimental colitis, which is relevant to the protective efficacy of intestinal barriers, inhibition of oxidative stress and excessive inflammatory response, and reprogramming of macrophage polarization. Hence, this study may facilitate a better understanding of the protective action of the EU against UC.

Cellular and molecular organization of the Drosophila foregut

The animal foregut is the first tissue to encounter ingested food, bacteria, and viruses. We characterized the adult Drosophila foregut using transcriptomics to better understand how it triages consumed items for digestion or immune response and manages resources. Cell types were assigned and validated using GFP-tagged and Gal4 reporter lines. Foregut-associated neuroendocrine cells play a major integrative role by coordinating gut activity with nutrition, the microbiome, and circadian cycles; some express clock genes. Multiple epithelial cell types comprise the proventriculus, the central foregut organ that secretes the peritrophic matrix (PM) lining the gut. Analyzing cell types synthesizing individual PM layers revealed abundant mucin production close to enterocytes, similar to the mammalian intestinal mucosa. The esophagus and salivary gland express secreted proteins likely to line the esophageal surface, some of which may generate a foregut commensal niche housing specific gut microbiome species. Overall, our results imply that the foregut coordinates dietary sensing, hormonal regulation, and immunity in a manner that has been conserved during animal evolution.

Small Intestine Bacterial Overgrowth is associated with increased Campylobacter and epithelial injury in duodenal biopsies of Bangladeshi children

Small intestine bacterial overgrowth (SIBO) has been associated with enteric inflammation, linear growth stunting, and neurodevelopmental delays in children from low-income countries. Little is known about the histologic changes or epithelial adherent microbiota associated with SIBO. We sought to describe these relationships in a cohort of impoverished Bangladeshi children. Undernourished 12-18-month-old children underwent both glucose hydrogen breath testing for SIBO and duodenoscopy with biopsy. Biopsy samples were subject to both histological scoring and 16s rRNA sequencing. 118 children were enrolled with 16s sequencing data available on 53. Of 11 histological features, we found that SIBO was associated with one, enterocyte injury in the second part of the duodenum (R = 0.21, p = 0.02). SIBO was also associated with a significant increase in Campylobacter by 16s rRNA analysis (Log 2-fold change of 4.43; adjusted p = 1.9 x 10-6). These findings support the growing body of literature showing an association between SIBO and enteric inflammation and enterocyte injury and further delineate the subgroup of children with environmental enteric dysfunction who have SIBO. Further, they show a novel association between SIBO and Campylobacter. Mechanistic work is needed to understand the relationship between SIBO, enterocyte injury, and Campylobacter.

SLE serum induces altered goblet cell differentiation and leakiness in human intestinal organoids

Human intestinal epithelial cells are the interface between luminal content and basally residing immune cells. They form a tight monolayer that constantly secretes mucus creating a multilayered protective barrier. Alterations in this barrier can lead to increased permeability which is common in systemic lupus erythematosus (SLE) patients. However, it remains unexplored how the barrier is affected. Here, we present an in vitro model specifically designed to examine the effects of SLE on epithelial cells. We utilize human colon organoids that are stimulated with serum from SLE patients. Combining transcriptomic with functional analyses revealed that SLE serum induced an expression profile marked by a reduction of goblet cell markers and changed mucus composition. In addition, organoids exhibited imbalanced cellular composition along with enhanced permeability, altered mitochondrial function, and an interferon gene signature. Similarly, transcriptomic analysis of SLE colon biopsies revealed a downregulation of secretory markers. Our work uncovers a crucial connection between SLE and intestinal homeostasis that might be promoted in vivo through the blood, offering insights into the causal connection of barrier dysfunction and autoimmune diseases.

Alleviative effects of exopolysaccharides from Limosilactobacillus mucosae CCFM1273 against ulcerative colitis via modulation of gut microbiota and inhibition of Fas/Fasl and TLR4/NF-κB pathways

Ulcerative colitis (UC) has become a public health challenge as its global prevalence increases annually. The use of prebiotics in healthcare has grown in recent years. Thus, the present study was designed to explore the alleviating effects and mechanisms of exopolysaccharides (EPS) produced by Limosilactobacillus mucosae CCFM1273 on UC. The results indicated that CCFM1273 EPS mitigated the disease symptoms and colonic pathologic damage in DSS-induced colitis mice. Moreover, CCFM1273 EPS improved the intestinal barrier by restoring goblet cell numbers and MUC2 production, enhancing intercellular junctions, and inhibiting epithelial cell apoptosis. In addition, CCFM1273 EPS inhibited colonic inflammation and oxidative stress. Importantly, CCFM1273 EPS augmented short-chain fatty acid (SCFA) producers, leading to increased levels of SCFAs (especially propionic acid), which inhibited the Fas/Fasl pathway and consequently inhibited epithelial apoptosis, and diminished Gram-negative bacteria, further decreasing lipopolysaccharides (LPS), which suppressed the TLR4/NF-κB pathway and consequently suppressed colonic inflammation, eventually relieving UC in mice. This study provides theoretical support for the use of prebiotics in clinical practice for UC.

Detection of High-Risk Human Papillomavirus Genotypes Among HIV-Infected Women in Four States in Nigeria

Introduction The World Health Organization states that almost all cervical cancer cases are linked to infection with high-risk human papillomaviruses transmitted through sexual contact. Implementing effective surveillance and preventive measures would enable the prevention of most cervical cancer cases, especially in HIV-infected women. Every year, about 12,000 women in Nigeria are diagnosed, with almost 8,000 deaths. HPV cervical cancer testing capacity is low in Nigeria. Testing scale-up and sensitization efforts across health facilities, including cervical tissue sample collection, are needed to reduce the cases of cervical cancer. This study aimed to assess the genotype-specific prevalence of clinically relevant high-risk HPV among women living with HIV in Nigeria. Methods A descriptive, cross-sectional study was conducted among adult HIV-infected women attending health facilities in four Nigerian states. From August to October 2022, cervical tissue was collected into PCR cell media, transported to the Nigerian Institute of Medical Research, and assayed for HPV presence and genotype using the Cobas 6800 System (Roche Diagnostics). Statistical analysis was conducted with Stata 2. Results A total of 4423 cervical swab samples were tested. The ages of women ranged from 18 to 72 years (mean 36.61±8.61). In our study, we found that 16.3% of participants tested positive for HPV. Among the high-risk HPV genotypes detected, HPV16 was present in 1.44% of participants, HPV18 in 1.29%, and other high-risk HPV (OHR-HPV) in 11.35%. Additionally, co-infections were observed, with 0.98% of participants testing positive for both HPV16 and OHR-HPV, 1.12% for HPV18 and OHR-HPV, and 0.12% for HPV16, HPV18, and OHR-HPV concurrently. However, 7.4% of the total results were deemed invalid. Conclusion OHR-HPV is prevalent among HIV-infected women across the north and west geopolitical zones of Nigeria. Policies and interventions geared towards curtailing the incidence of cervical cancer are fervently solicited.

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.

Microbiota-gut-brain axis and its therapeutic applications in neurodegenerative diseases

The human gastrointestinal tract is populated with a diverse microbial community. The vast genetic and metabolic potential of the gut microbiome underpins its ubiquity in nearly every aspect of human biology, including health maintenance, development, aging, and disease. The advent of new sequencing technologies and culture-independent methods has allowed researchers to move beyond correlative studies toward mechanistic explorations to shed light on microbiome-host interactions. Evidence has unveiled the bidirectional communication between the gut microbiome and the central nervous system, referred to as the "microbiota-gut-brain axis". The microbiota-gut-brain axis represents an important regulator of glial functions, making it an actionable target to ameliorate the development and progression of neurodegenerative diseases. In this review, we discuss the mechanisms of the microbiota-gut-brain axis in neurodegenerative diseases. As the gut microbiome provides essential cues to microglia, astrocytes, and oligodendrocytes, we examine the communications between gut microbiota and these glial cells during healthy states and neurodegenerative diseases. Subsequently, we discuss the mechanisms of the microbiota-gut-brain axis in neurodegenerative diseases using a metabolite-centric approach, while also examining the role of gut microbiota-related neurotransmitters and gut hormones. Next, we examine the potential of targeting the intestinal barrier, blood-brain barrier, meninges, and peripheral immune system to counteract glial dysfunction in neurodegeneration. Finally, we conclude by assessing the pre-clinical and clinical evidence of probiotics, prebiotics, and fecal microbiota transplantation in neurodegenerative diseases. A thorough comprehension of the microbiota-gut-brain axis will foster the development of effective therapeutic interventions for the management of neurodegenerative diseases.

MUC17 is an essential small intestinal glycocalyx component that is disrupted in Crohn's disease

Crohn's disease (CD) is the chronic inflammation of the ileum and colon triggered by bacteria, but insights into molecular perturbations at the bacteria-epithelium interface are limited. We report that membrane mucin MUC17 protects small intestinal enterocytes against commensal and pathogenic bacteria. In non-inflamed CD ileum, reduced MUC17 levels correlated with a compromised glycocalyx, allowing bacterial contact with enterocytes. Muc17 deletion in mice rendered the small intestine prone to atypical infection while maintaining resistance to colitis. The loss of Muc17 resulted in spontaneous deterioration of epithelial homeostasis and extra-intestinal translocation of bacteria. Finally, Muc17-deficient mice harbored specific small intestinal bacterial taxa observed in CD. Our findings highlight MUC17 as an essential line of defense in the small intestine with relevance for early epithelial defects in CD.

Piezo channels in the intestinal tract

The intestine is the largest mechanosensitive organ in the human body whose epithelial cells, smooth muscle cells, neurons and enteroendocrine cells must sense and respond to various mechanical stimuli such as motility, distension, stretch and shear to regulate physiological processes including digestion, absorption, secretion, motility and immunity. Piezo channels are a newly discovered class of mechanosensitive ion channels consisting of two subtypes, Piezo1 and Piezo2. Piezo channels are widely expressed in the intestine and are involved in physiological and pathological processes. The present review summarizes the current research progress on the expression, function and regulation of Piezo channels in the intestine, with the aim of providing a reference for the future development of therapeutic strategies targeting Piezo channels.

Acute gastrointestinal permeability after traumatic brain injury in mice precedes a bloom in Akkermansia muciniphila supported by intestinal hypoxia

Traumatic brain injury (TBI) increases gastrointestinal morbidity and associated mortality. Clinical and preclinical studies implicate gut dysbiosis as a consequence of TBI and an amplifier of brain damage. However, little is known about the association of gut dysbiosis with structural and functional changes of the gastrointestinal tract after an isolated TBI. To assess gastrointestinal dysfunction, mice received a controlled cortical impact or sham brain injury and intestinal permeability was assessed at 4 h, 8 h, 1 d, and 3 d after injury by oral administration of 4 kDa FITC Dextran prior to euthanasia. Quantification of serum fluorescence revealed an acute, short-lived increase in permeability 4 h after TBI. Despite transient intestinal dysfunction, no overt morphological changes were evident in the ileum or colon across timepoints from 4 h to 4 wks post-injury. To elucidate the timeline of microbiome changes after TBI, 16 s gene sequencing was performed on DNA extracted from fecal samples collected prior to and over the first month after TBI. Differential abundance analysis revealed that the phylum Verrucomicrobiota was increased at 1, 2, and 3 d after TBI. The Verrucomicrobiota species was identified by qPCR as Akkermansia muciniphila, an obligate anaerobe that resides in the intestinal mucus bilayer and produces short chain fatty acids (e.g. butyrate) utilized by intestinal epithelial cells. We postulated that TBI promotes intestinal changes favorable for the bloom of A. muciniphila. Consistent with this premise, the relative area of mucus-producing goblet cells in the medial colon was significantly increased at 1 d after injury, while colon hypoxia was significantly increased at 3 d. Our findings reveal acute gastrointestinal functional changes coupled with an increase of beneficial bacteria suggesting a potential compensatory response to systemic stress after TBI.

Malvidin alleviates LPS-induced septic intestinal injury through the nuclear factor erythroid 2-related factor 2/reactive oxygen species/NLRP3 inflammasome pathway

Emerging evidence suggests that the gastrointestinal tract plays a crucial role in the pathophysiology of sepsis, a leading cause of mortality among patients admitted to the intensive care unit (ICU). Malvidin, belonging to the flavonoid family of compounds, exhibits a range of capabilities including anti-inflammatory and antioxidant properties. Studies have demonstrated that Malvidin exhibits a dose-dependent effect in mitigating sepsis-induced intestinal injury. The advantageous impact of Malvidin in safeguarding against sepsis-induced intestinal injury is associated with its capacity to counteract oxidative stress, inhibit cellular apoptosis, diminish the secretion of pro-inflammatory cytokines, and regulate the synthesis of inflammasomes. The findings indicate that Malvidin, a natural compound, exhibits protective effects on the gut by activating the nuclear factor erythroid 2-related factor 2/reactive oxygen species/NLRP3 inflammasome pathway. These results have significant implications for potential clinical applications and offer valuable insights into the treatment of sepsis-induced intestinal injury.

Chlorogenic acid protects against intestinal inflammation and injury by inactivating the mtDNA-cGAS-STING signaling pathway in broilers under necrotic enteritis challenge

This study aimed to determine the effects of chlorogenic acid (CGA) on the growth performance, intestinal health, immune response, and mitochondrial DNA (mtDNA)-cyclic GMP-AMP synthase (cGAS)-stimulator of interferon genes (STING) signaling pathway in broilers under necrotic enteritis (NE) challenge. The 180 one-day-old male Cobb 500 broilers with similar body weight of 44.59 ± 1.39 g were randomly allocated into 3 groups. The groups were control diet (Control group), control diet + NE challenge (NE group), and control diet + 500 mg/kg CGA + NE challenge (NE + CGA group), with 6 replicates per treatment. All broilers except the Control group were given sporulated coccidian oocysts (d 14) and Clostridium perfringens (d 19-21) by oral gavage. Our findings showed that CGA improved the growth performance and intestinal morphology in broilers under NE challenge. CGA supplementation elevated the barrier function in broilers under NE challenge, which reflected in the decreased serum concentrations of D-lactate and diamine oxidase, and upregulated jejunal protein expression of occludin. CGA supplementation also improved the immune function, which reflected in the increased concentrations and gene expressions of anti-inflammatory factors, and decreased concentrations and gene expressions of proinflammatory factors. CGA supplementation further enhanced intestinal cell proliferation and differentiation, which manifested in the increased number of goblet cells and positive cells of proliferating cell nuclear antigen on d 28 and 42. Furthermore, CGA supplementation decreased the mtDNA (d 42) and mitochondrial reactive oxygen species levels (d 28 and 42), and increased the mitochondrial membrane potential (d 42) and mitochondrial complex I (d 28 and 42) or III (d 28) activity. Broilers challenged with NE had upregulated jejunal protein expressions of cGAS, phospho-TANK-binding kinase 1, and phospho-interferon regulatory factor 7 compared with the Control group, which were downregulated after CGA supplementation. In conclusion, dietary supplementation CGA could protect against intestinal inflammation and injury by reducing the leakage of mtDNA and inactivating the cGAS-STING signaling pathway in broilers under NE challenge.

Gut-Liver Axis as a Therapeutic Target for Drug-Induced Liver Injury

Drug-induced liver injury (DILI) is a liver disease that remains difficult to predict and diagnose, and the underlying mechanisms are yet to be fully clarified. The gut-liver axis refers to the reciprocal interactions between the gut and the liver, and its homeostasis plays a prominent role in maintaining liver health. It has been recently reported that patients and animals with DILI have a disrupted gut-liver axis, involving altered gut microbiota composition, increased intestinal permeability and lipopolysaccharide translocation, decreased short-chain fatty acids production, and impaired bile acid metabolism homeostasis. The present review will summarize the evidence from both clinical and preclinical studies about the role of the gut-liver axis in the pathogenesis of DILI. Moreover, we will focus attention on the potential therapeutic strategies for DILI based on improving gut-liver axis function, including herbs and phytochemicals, probiotics, fecal microbial transplantation, postbiotics, bile acids, and Farnesoid X receptor agonists.

Dietary supplementation of ark clams protects gut health and modifies gut microbiota in d-galactose-induced aging rats

BACKGROUND

Ark clams, a seafood abundant in various nutrients, are widely consumed worldwide. This study aimed to investigate the protective benefits of two common ark clams in Korea, Scapharca subcrenata (SS) and Tegillarca granosa (TG), on gut health in d-galactose (d-gal)-induced aging rats.

RESULTS

Thirty-two Wistar rats (11 weeks old) were randomly allocated into four groups: a CON group (normal diet + saline intraperitoneal (i.p.) injection), a CD group (normal diet + d-gal i.p. injection), an SS group (normal diet with 5% SS supplementation + d-gal i.p. injection), and a TG group (normal diet with 5% TG supplementation + d-gal i.p. injection). After 12 weeks of treatment, histopathological results showed that gut barrier damage was alleviated in rats of the SS and TG groups, as evidenced by increases in mucus layer thickness and goblet cell numbers. Meanwhile, the two groups supplemented with ark clams showed an evident reduction in oxidative stress biomarkers (malondialdehyde and protein carbonyl content levels in the colon) and an increase in the immune-related factor (immunoglobulin A level in the plasma) in rats. The 16S ribosomal RNA analysis revealed that SS and TG ark clams significantly increased the proliferations of Bacteroidetes at the phylum level and Parabacteroides at the genus level. Additionally, the levels of the three main short-chain fatty acids in the cecal contents were also significantly increased in the SS and TG groups.

CONCLUSION

Our results indicated a potent preventive effect of SS and TG ark clams on d-gal-induced gut injury, suggesting that ark clams may be a promising dietary component for intervening in aging. © 2023 Society of Chemical Industry.

Effects of Helicobacter pylori infection on intestinal microbiota, immunity and colorectal cancer risk

Infecting about half of the world´s population, Helicobacter pylori is one of the most prevalent bacterial infections worldwide and the strongest known risk factor for gastric cancer. Although H. pylori colonizes exclusively the gastric epithelium, the infection has also been associated with various extragastric diseases, including colorectal cancer (CRC). Epidemiological studies reported an almost two-fold increased risk for infected individuals to develop CRC, but only recently, direct causal and functional links between the chronic infection and CRC have been revealed. Besides modulating the host intestinal immune response, H. pylori is thought to increase CRC risk by inducing gut microbiota alterations. It is known that H. pylori infection not only impacts the gastric microbiota at the site of infection but also leads to changes in bacterial colonization in the distal large intestine. Considering that the gut microbiome plays a driving role in CRC, H. pylori infection emerges as a key factor responsible for promoting changes in microbiome signatures that could contribute to tumor development. Within this review, we want to focus on the interplay between H. pylori infection, changes in the intestinal microbiota, and intestinal immunity. In addition, the effects of H. pylori antibiotic eradication therapy will be discussed.

Liensinine alleviates mouse intestinal injury induced by sepsis through inhibition of oxidative stress, inflammation, and cell apoptosis

Sepsis is a clinical syndrome triggered by an imbalanced host response to pathogens that can lead to multiple organ dysfunction. The immune response and barrier function of the gut play an important role in the pathogenesis and progression of sepsis. This study aimed to explore the potential role of natural alkaloid Liensinine in the treatment of intestinal injury caused by sepsis and its possible molecular mechanism. In this study, a mouse model of sepsis was established by injecting LPS to explore the protective effect of Liensinine on intestinal injury in sepsis. The results showed that Liensinine could reduce the intestinal damage caused by LPS and increase the number of goblet cells. Furthermore, it decreased the release of inflammatory cytokines by inhibiting NF-kB phosphorylation and NLRP3 inflammasome synthesis. Liensinine also reduced the oxidative stress and ROS accumulation caused by LPS, and played an anti-oxidative stress role by regulating the Nrf2/keap1 signaling pathway. In addition, Liensinine alleviated the inhibition of intestinal autophagy caused by LPS by inhibiting the PI3K/Akt/mTOR pathway. And then it reduced the excessive apoptosis of intestinal cells. This study provides valuable insights for sepsis prevention and treatment, offering a potential therapeutic candidate to protect against intestinal injury and regulate the inflammatory response in sepsis.

Modulation of Acute Intestinal Inflammation by Dandelion Polysaccharides: An In-Depth Analysis of Antioxidative, Anti-Inflammatory Effects and Gut Microbiota Regulation

Acute colitis is a complex disease that can lead to dysregulation of the gut flora, inducing more complex parenteral diseases. Dandelion polysaccharides (DPSs) may have potential preventive and therapeutic effects on enteritis. In this study, LPS was used to induce enteritis and VC was used as a positive drug control to explore the preventive and therapeutic effects of DPS on enteritis. The results showed that DPS could repair the intestinal barrier, down-regulate the expression of TNF-α, IL-6, IL-1β, and other pro-inflammatory factors, up-regulate the expression of IL-22 anti-inflammatory factor, improve the antioxidant capacity of the body, and improve the structure of intestinal flora. It is proved that DPS can effectively prevent and treat LPS-induced acute enteritis and play a positive role in promoting intestinal health.

Glutamine attenuates bisphenol A-induced intestinal inflammation by regulating gut microbiota and TLR4-p38/MAPK-NF-κB pathway in piglets

Bisphenol A (BPA), as a kind of widely exerted environmental hazardous material, brings toxicity to both humans and animals. This study aimed to investigate the role of glutamine (Gln) in intestinal inflammation and microbiota in BPA-challenged piglets. Thirty-two piglets were randomly divided into four groups according to 2 factors including BPA (0 vs. 0.1%) and Gln (0 vs. 1%) supplemented in basal diet for a 42-day feeding experiment. The results showed BPA exposure impaired piglet growth, induced intestinal inflammation and disturbed microbiota balance. However, dietary Gln supplementation improved the growth performance, while decreasing serum pro-inflammatory cytokine levels in BPA-challenged piglets. In addition, Gln attenuated intestinal mucosal damage and inflammation by normalizing the activation of toll-like receptor 4 (TLR4)-p38/MAPK-nuclear factor-kappa B (NF-κB) pathway caused by BPA. Moreover, dietary Gln supplementation decreased the abundance of Actinobacteriota and Proteobacteria, and attenuated the decreased abundance of Roseburia, Prevotella, Romboutsia and Phascolarctobacterium and the content of short-chain fatty acids in cecum contents caused by BPA exposure. Moreover, there exerted potential relevance between the gut microbiota and pro-inflammatory cytokines and cecal short-chain fatty acids. In conclusion, Gln is critical nutrition for attenuating BPA-induced intestinal inflammation, which is partially mediated by regulating microbial balance and suppressing the TLR4/p38 MAPK/NF-κB signaling.