Metabolic interactions shape emergent biofilm structures in a conceptual model of gut mucosal bacterial communities.

The gut microbiome plays a major role in human health; however, little is known about the structural arrangement of microbes and factors governing their distribution. In this work, we present an in silico agent-based model (ABM) to conceptually simulate the dynamics of gut mucosal bacterial communities. We explored how various types of metabolic interactions, including competition, neutralism, commensalism, and mutualism, affect community structure, through nutrient consumption and metabolite exchange. Results showed that, across scenarios with different initial species abundances, cross-feeding promotes species coexistence. Morphologically, competition and neutralism resulted in segregation, while mutualism and commensalism fostered high intermixing. In addition, cooperative relations resulted in community properties with little sensitivity to the selective uptake of metabolites produced by the host. Moreover, metabolic interactions strongly influenced colonization success following the invasion of newcomer species. These results provide important insights into the utility of ABM in deciphering complex microbiome patterns.

Moxibustion Regulates the BRG1/Nrf2/HO-1 Pathway by Inhibiting MicroRNA-222-3p to Prevent Oxidative Stress in Intestinal Epithelial Cells in Ulcerative Colitis and Colitis-Associated Colorectal Cancer.

Oxidative stress is crucial in ulcerative colitis (UC) and colitis-associated colorectal cancer (CAC). Intestinal epithelial cells (IECs) are an important component of the intestinal barrier. In previous studies, we have demonstrated that suppressing microRNA-222-3p (miR-222-3p) can protect against oxidative stress in IECs, which ameliorates colonic injuries in UC mice and prevents the conversion of UC to CAC. In this case, we hope to explore whether moxibustion can alleviate UC and CAC by inhibiting miR-222-3p based on mouse models of UC and CAC. After herb-partitioned moxibustion (HPM) intervention, the disease activity index (DAI) and colon macroscopic damage index (CMDI) were significantly reduced in UC mice, and the number and volume of intestinal tumors were decreased considerably in CAC mice. Meanwhile, we found that HPM suppressed miR-222-3p expression and upregulated the mRNA and protein expression of Brahma-related gene 1 (BRG1), nuclear factor erythroid 2-related factor 2 (Nrf2), heme oxygenase-1 (HO-1), while inhibiting Kelch-like ECH-associated protein 1 (Keap1) expression in IECs of UC and CAC mice. With changes in reactive oxygen species (ROS), malondialdehyde (MDA), glutathione peroxidase (GSH-Px), and inflammatory cytokines interleukin (IL)-1ß and tumor necrosis factor (TNF)-α), we verified that HPM protects against oxidative stress and inflammation in IECs of UC and CAC mice. The effect of HPM was inhibited in miR-222-3p overexpression mice, further demonstrating that the protective effect of HPM on UC and CAC mice was through inhibiting miR-222-3p. In summary, HPM regulates the BRG1/Nrf2/HO-1 pathway by inhibiting miR-222-3p to attenuate oxidative stress in IECs in UC and CAC.

Bowel Inflammation and Nutrient Supplementation: Effects of a Fixed Combination of Probiotics, Vitamins, and Herbal Extracts in an In Vitro Model of Intestinal Epithelial Barrier Dysfunction.

The gut microbiota is a very important factor in the state of health of an individual, its alteration implies a situation of "dysbiosis," which can be connected to functional gastrointestinal disorders and pathological conditions, such as Inflammatory Bowel Disease (IBD), Irritable Bowel Syndrome (IBS), Ulcerative Colitis (UC) and Crohn's Disease (CD), and Colorectal Cancer (CRC). In this work, we studied the effect of a food supplement called ENTERO-AD containing a mix of probiotics (Lactobacillus acidophilus LA1, L. reuteri LR92, Bifidobacterium breve Bbr8), Matricaria Chamomilla, and B group vitamins (B1, B2, B6) on intestinal inflammation. The in vitro model used for the study is the Caco-2 cell, a culture derived from human intestinal adenocarcinoma; the inflammatory condition was achieved with treatment with Lipopolysaccharide (LPS) and the association between Tumor necrosis factor α/Interferon γ (TNF-α/IFN-γ) [1,2]. The effect of ENTERO-AD was evaluated by cell viability, measures of Transepithelial Electrical Resistance (TEER), paracellular permeability, and immunofluorescence. Results of the study have shown that ENTERO-AD has a favorable effect on Caco-2 cells in inflammatory conditions. It improves the integrity of Occludin and Zonula Occludens-1 (ZO-1) proteins, leading to an improvement in terms of TEER values and a reduction of paracellular permeability. This evidence underlines the protective effect of ENTERO-AD and its components in intestinal inflammation.

Organization of a cytoskeletal superstructure in the apical domain of intestinal tuft cells.

Tuft cells are a rare epithelial cell type that play important roles in sensing and responding to luminal antigens. A defining morphological feature of this lineage is the actin-rich apical "tuft," which contains large fingerlike protrusions. However, details of the cytoskeletal ultrastructure underpinning the tuft, the molecules involved in building this structure, or how it supports tuft cell biology remain unclear. In the context of the small intestine, we found that tuft cell protrusions are supported by long-core bundles that consist of F-actin crosslinked in a parallel and polarized configuration; they also contain a tuft cell-specific complement of actin-binding proteins that exhibit regionalized localization along the bundle axis. Remarkably, in the sub-apical cytoplasm, the array of core actin bundles interdigitates and co-aligns with a highly ordered network of microtubules. The resulting cytoskeletal superstructure is well positioned to support subcellular transport and, in turn, the dynamic sensing functions of the tuft cell that are critical for intestinal homeostasis.

Melatonin Prevents Thioacetamide-Induced Gut Leakiness and Liver Fibrosis Through the Gut-Liver Axis via Modulating Sirt1-Related Deacetylation of Gut Junctional Complex and Hepatic Proteins.

Intestinal barrier dysfunction with high serum endotoxin is common in patients with liver fibrosis, but the mechanisms underlying liver fibrosis remain unclear. Melatonin is a well-recognized antioxidant and an anti-inflammatory agent that benefits multiple organs. However, the beneficial effects of melatonin on gut leakiness-associated liver fibrosis have not been systemically studied. Here, we investigated the protective mechanisms of melatonin against thioacetamide (TAA)-induced gut barrier dysfunction and hepatic fibrosis by focusing on posttranslational protein modifications through the gut-liver axis. Our results showed that gut leakiness markers, including decreased gut tight/adherens junction proteins (TJ/AJs) with increased intestinal deformation, apoptosis, and serum endotoxin, were observed early at 1 week after TAA exposure. Liver injury, apoptosis, and fibrosis were prominent at 2 and 4 weeks. Mechanistically, we found that gut TJ/AJs were hyper-acetylated, followed by ubiquitin-dependent proteolysis, leading to their degradation and gut leakiness. Gut dysbiosis, hepatic protein hyper-acetylation, and SIRT1 downregulation were also observed. Consistently, intestinal Sirt1 deficiency greatly enhanced protein hyper-acetylation, gut leakiness, endotoxemia, and liver fibrosis. Pretreatment with melatonin prevented or improved all these changes in both the gut and liver. Furthermore, melatonin blunted protein acetylation and injury in TAA-exposed T84 human intestinal and AML12 mouse liver cells. Overall, this study demonstrated novel mechanisms by which melatonin prevents gut leakiness and liver fibrosis through the gut-liver axis by attenuating the acetylation of intestinal and hepatic proteins. Thus, melatonin consumption can become a potentially safe supplement for liver fibrosis patients by preventing protein hyper-acetylation and gut leakiness.

Antibiotics damage the colonic mucus barrier in a microbiota-independent manner.

Antibiotic use is a risk factor for development of inflammatory bowel diseases (IBDs). IBDs are characterized by a damaged mucus layer, which does not separate the intestinal epithelium from the microbiota. Here, we hypothesized that antibiotics affect the integrity of the mucus barrier, which allows bacterial penetrance and predisposes to intestinal inflammation. We found that antibiotic treatment led to breakdown of the colonic mucus barrier and penetration of bacteria into the mucus layer. Using fecal microbiota transplant, RNA sequencing followed by machine learning, ex vivo mucus secretion measurements, and antibiotic treatment of germ-free mice, we determined that antibiotics induce endoplasmic reticulum stress in the colon that inhibits colonic mucus secretion in a microbiota-independent manner. This antibiotic-induced mucus secretion flaw led to penetration of bacteria into the colonic mucus layer, translocation of microbial antigens into circulation, and exacerbation of ulcerations in a mouse model of IBD. Thus, antibiotic use might predispose to intestinal inflammation by impeding mucus production.

Vitamin B12 ameliorates gut epithelial injury via modulating the HIF-1 pathway and gut microbiota.

Inflammatory bowel diseases (IBDs) are immune chronic diseases characterized by recurrent episodes, resulting in continuous intestinal barrier damage and intestinal microbiota dysbiosis. Safe strategies aimed at stabilizing and reducing IBDs recurrence have been vigorously pursued. Here, we constructed a recurrent intestinal injury Drosophila model and found that vitamin B12 (VB12), an essential co-factor for organism physiological functions, could effectively protect the intestine and reduce dextran sulfate sodium-induced intestinal barrier disruption. VB12 also alleviated microbial dysbiosis in the Drosophila model and inhibited the growth of gram-negative bacteria. We demonstrated that VB12 could mitigate intestinal damage by activating the hypoxia-inducible factor-1 signaling pathway in injured conditions, which was achieved by regulating the intestinal oxidation. In addition, we also validated the protective effect of VB12 in a murine acute colitis model. In summary, we offer new insights and implications for the potential supportive role of VB12 in the management of recurrent IBDs flare-ups.

5-Methoxytryptophan Alleviates Dextran Sulfate Sodium-Induced Colitis by Inhibiting the Intestinal Epithelial Damage and Inflammatory Response.

Background: Colitis is a refractory intestinal inflammatory disease significantly affecting the quality of a patient's life and increasing the risk of exacerbation. The primary factors leading to colitis encompass infections, insufficient blood flow, and the buildup of collagen as well as white blood cells. Among various available therapeutics, 5-methoxytryptophan (5-MTP) has emerged as one of the protectants by inhibiting inflammatory damage. Nonetheless, there is no report on the role of 5-MTP in the treatment of colitis. Materials and Methods: To verify the anti-inflammatory effect of 5-MTP in vivo, we first constructed mouse model with dextran sulfate sodium-induced colitis. Furthermore, the macrophage infiltration and release of inflammatory factors through western blot (WB) and hematoxylin-eosin staining analyses were examined. Intestinal epithelial cell tight junction damage and apoptosis were investigated by WB analysis, immunofluorescence, and terminal deoxynucleotidyl transferase dUTP nick end labeling staining. Finally, we examined the generation of cellular inflammation and analyzed the influence of 5-MTP on M1 polarization at the cellular level. Results: This study initially confirmed that 5-MTP possessed an excellent therapeutic effect on colitis. 5-MTP inhibits macrophage infiltration and the generation of inflammatory factors. In addition to its effects on immune cells, 5-MTP significantly inhibits intestinal epithelial cell tight junction damage and apoptosis in vivo. Moreover, it inhibits inflammation and M1 polarization response in vitro. Conclusion: 5-MTP counteracts excessive inflammation, thereby preventing intestinal epithelial tight junction damage. In addition, inhibition of apoptosis suggests that 5-MTP may be a potential therapeutic agent for colitis.

Duodenal-Jejunal Bypass Restores Sweet Taste Receptor-Mediated Glucose Sensing and Absorption in Diabetic Rats.

Aim: The aim of the study is to identify the regulatory role of intestinal sweet taste receptors (STRs) and glucose transporters (SGLT1, GLUT2) and gut peptide secretion in duodenal-jejunal bypass (DJB)-ameliorated glycemic control in Type 2 diabetes. Materials and Methods: DJB and sham surgeries were performed in streptozotocin-induced diabetic male rats. The blood GLP-1 and GLP-2 levels were evaluated under feeding and fasting conditions. The expression of STRs (T1R2, T1R3), sweet taste signaling effector (Gα-gustducin), SGLT1, and GLUT2 was detected in the intestinal alimentary limb (A limb), biliopancreatic limb (BP limb), and common limb (C limb). The effects of STR inhibition on glucose control were measured with lactisole. Results: Glucose tolerance was improved in DJB-operated rats compared with the sham group, similar to that of normal control rats, without significant differences in food intake and body weight. The plasma GLP-1 levels of DJB rats were increased under diet-fed condition, and GLP-2 levels were increased after fasting. The villus height and crypt depth were significantly increased in the A limb of DJB-operated rats. In addition, GLP-1 expression was restored in enterocytes. The expression of T1R2, Gα-gustducin, and SGLT1 was elevated in the A limb after DJB, while GLUT2 was downregulated in the A, BP, and C limbs. The localization of GLUT2 was normalized in the three intestinal limbs after DJB. However, the beneficial effects of DJB on glucose control were abolished in the presence of lactisole in vivo. Conclusion: DJB ameliorates glycemic control probably by restoring STR-mediated glucose sensing and absorption with the responses of GLP-1 and GLP-2 to carbohydrate.

Sirtuin 6 inhibits group 3 innate lymphoid cell function and gut immunity by suppressing IL-22 production.

Introduction: Group 3 innate lymphoid cells (ILC3s) are enriched in the intestinal mucosa and play important roles in host defense against infection and inflammatory diseases. Sirtuin 6 (SIRT6) is a nicotinamide adenine dinucleotide (NAD+)- dependent deacetylase and has been shown to control intestinal epithelial cell differentiation and survival. However, the role of SIRT6 in ILC3s remains unknown. Methods: To investigate the role of SIRT6 in gut ILC3s, we generated SIRT6 conditional knockout mice by crossing Rorccre and Sirt6flox/flox mice. Cell number and cytokine production was examined using flow cytometry. Citrobacter rodentium infection and dextran sodium sulfate-induced colitis models were used to determine the role of SIRT6 in gut defense. RT-qPCR, flow cytometry and immunohistochemistry were used to assess the intestinal inflammatory responses. Results: Here we show that SIRT6 inhibits IL-22 expression in intestinal ILC3s in a cell-intrinsic manner. Deletion of SIRT6 in ILC3s does not affect the cell numbers of total ILC3s and subsets, but results in increased IL-22 production. Furthermore, ablation of SIRT6 in ILC3s protects mice against Citrobacter rodentium infection and dextran sodium sulfate-induced colitis. Our results suggest that SIRT6 may play a role in ILC3 function by regulating gut immune responses against bacterial infection and inflammation. Discussion: Our finding provided insight into the relation of epigenetic regulators with IL-22 production and supplied a new perspective for a potential strategy against inflammatory bowel disease.

Role of chemokine receptors in gastrointestinal mucosa.

Chemokine receptors are essential for the immune response in the oral and gut mucosa. The gastrointestinal mucosa is characterized by the presence of immune populations because it is susceptible to inflammatory and infectious diseases, necessitating immune surveillance. Chemokine receptors are expressed on immune cells and play a role in gastrointestinal tissue-homing, although other non-immune cells also express them for various biological functions. CCR9, CXCR3 and CXCR6 play an important role in the T cell response in inflammatory and neoplastic conditions of the gastrointestinal mucosa. However, CXCR6 could also be found in gastric cancer cells, highlighting the different roles of chemokine receptors in different pathologies. On the other hand, CCR4 and CCR8 are critical for Treg migration in gastrointestinal tissues, correlating with poor prognosis in mucosal cancers. Other chemokine receptors are also important in promoting myeloid infiltration with context-dependent roles. Further, CXCR4 and CXCR7 are also present in gastrointestinal tumor cells and are known to stimulate proliferation, migration, and invasion into other tissues, among other pro-tumorigenic functions. Determining the processes underlying mucosal immunity and creating tailored therapeutic approaches for gastrointestinal diseases requires an understanding of the complex interactions that occur between chemokine receptors and their ligands in these mucosal tissues.

Duodenal and colonic mucosal S100A8/A9 (calprotectin) expression is increased and correlates with the severity of select histologic lesions in dogs with chronic inflammatory enteropathy.

BACKGROUND: Calprotectin, a damage-associated molecular pattern protein of the S100/calgranulin family, is a potential marker of gastrointestinal inflammation in dogs and mainly originates from activated macrophages and granulocytes. Increased calprotectin concentrations are reported in feces and serum samples from dogs with chronic inflammatory enteropathy (CIE), but mucosal calprotectin expression has not been extensively investigated in canine CIE. Thus, we aimed to evaluate gastrointestinal mucosal concentrations of calprotectin in 62 dogs (44 dogs with CIE compared to 18 healthy Beagles) using a particle-enhanced turbidimetric immunoassay method. Additionally, we assessed the relationship of gastric, duodenal, jejunal, ileal, and colonic mucosal calprotectin levels with the clinical disease severity (canine clinical inflammatory bowel disease activity index, CIBDAI), histopathologic findings, clinical outcome, and serum albumin concentrations to further evaluate the potential of calprotectin as a biomarker for CIE. RESULTS: Mucosal calprotectin concentrations in dogs with CIE were significantly higher in the duodenum (median: 276.2 µg/g) and colon (median: 298.2 µg/g) compared to healthy controls (median: 94.3 µg/g, P = 0.0039; and median: 112.0 µg/g, P = 0.0061). Similar numerical differences in the ileum and cecum were not statistically significant, and mucosal calprotectin concentrations correlated significantly among the different gastrointestinal segments. Histologic lesion severity was linked to mucosal calprotectin concentrations for inflammatory and structural histology criteria in the duodenum and colon (all P < 0.05). Higher mucosal calprotectin levels in the duodenum and across all segments correlated with lower serum albumin concentrations (both P < 0.05); duodenal mucosal calprotectin concentrations were more than sixfold higher in hypoalbuminemic dogs (median: 1441 µg/g, n = 4) than normoalbuminemic dogs (median: 227 µg/g, n = 40). There was no significant association of mucosal calprotectin levels with CIBDAI scores or individual clinical outcomes. CONCLUSIONS: These results show that duodenal and colonic mucosal calprotectin concentrations are increased in dogs with CIE, providing further supporting evidence for the diagnostic potential of fecal calprotectin (presumably reflecting mucosal) concentrations and in dogs with CIE. Further longitudinal research is needed to assess changes in mucosal calprotectin concentrations with clinical response to treatment vs. mucosal disease remission and to determine the clinical utility of fecal calprotectin concentrations to diagnose and monitor dogs with CIE in clinical practice.

Milk-derived extracellular vesicles enable gut-to-tumor oral delivery of tumor-activated doxorubicin prodrugs.

Rationale: Oral chemotherapy has been emerging as a hopeful therapeutic regimen for the treatment of various cancers because of its high safety and convenience, lower costs, and high patient compliance. Despite the current advancements in nanoparticle-mediated drug delivery, numerous anticancer drugs susceptible to the hostile gastrointestinal (GI) environment exhibit poor permeability across the intestinal epithelium, rendering them ineffective in providing therapeutic benefits. In this paper, we focus on harnessing milk-derived extracellular vesicles (mEVs) for gut-to-tumor oral drug delivery by leveraging their high bioavailability. Methods: The tumor-activated prodrug (a cathepsin B-specific cleavable FRRG peptide and doxorubicin, FDX) is used as a model drug and is complexed with mEVs, resulting in FDX@mEVs. To verify stability in the GI tract, prolonged intestinal retention, and enhanced trans-epithelial transport via neonatal Fc receptor (FcRn)-mediated transcytosis, intestinal transport evaluation is conducted using in vitro intestinal barrier model and mouse model. Results: FDX@mEVs form a stable nanostructure with an average diameter of 131.1 ± 70.5 nm and complexation processes do not affect the inherent properties of FDX. Orally administered FDX@mEVs show significantly improved bioavailability compared to uncomplexed FDX via FcRn-mediated transcytosis of mEVs resulting in increased tumor accumulation of FDX in tumor-bearing mouse model. Conclusions: After oral administration of FDX@mEVs, it is observed that remarkable antitumor efficacy in colon tumor-bearing mice without adverse effects, such as body weight loss, liver/kidney dysfunction, and cardiotoxicity.

Engineered plant-derived extracellular vesicles for targeted regulation and treatment of colitis-associated inflammation.

Rationale: Inflammatory bowel disease (IBD) is a chronic disorder characterized by persistent inflammation of the gastrointestinal tract. Due to the elusive causes and complex mechanisms of this disorder, the development of highly effective therapeutic drugs is crucial. Extracellular vesicles (EVs) are small membrane-bound structures released by cells into the surrounding environment. Recent research has witnessed a substantial surge in the utilization of plant-derived EVs that offer advantages such as high productivity, low production costs, diverse biological functions, and low cytotoxicity. Herein, Red cabbage-derived EVs (Rabex) were investigated and engineered as potential therapeutic agents for IBD. Methods: Rabex was engineered by surface conjugation with hyaluronic acid (t-Rabex) to simultaneously enhance the targeting of intestinal epithelial and immune cells, thereby improving their therapeutic targeting and efficacy. The properties and therapeutic potential of t-Rabex were assessed through both in vitro studies and in vivo experiments, focusing on their capacity to reach the gastrointestinal tract and exert a therapeutic effect compared to unmodified Rabex. Results: Rabex exhibited dual functions, including the suppression of inflammation in macrophages and promotion of colon epithelial cell regeneration, both of which are critical for effective IBD treatment. In vitro and in vivo studies of t-Rabex have demonstrated its superior targeting efficiency to the gastrointestinal tract and therapeutic efficacy compared to Rabex, making it a promising and more effective IBD treatment. Understanding the mechanism of action of t-Rabex in colonic tissues highlighted its anti-inflammatory, antioxidative, and tight-junction maintenance properties. Conclusions: These findings underscore the potential of t-Rabex as a precise therapeutic agent for IBD and shed light on the diverse applications of plant-derived EVs.

Pericentriolar material 1 promotes intestinal inflammation in ulcerative colitis by activating NLRP3/gasdermin D-mediated macrophage pyroptosis.

Excessive proinflammatory cytokine release induced by pyroptosis plays a vital role in intestinal mucosal inflammation in ulcerative colitis (UC). Several pyroptosis-related factors are regulated by the centrosome. Pericentriolar material 1 (PCM1) is a primary component of centriolar satellites that is present as cytoplasmic granules around the centrosome. Our previous study revealed that PCM1 was highly expressed in UC patients, but the role of PCM1 in UC remains unknown. This study aimed to elucidate the role of PCM1 in the development of UC, especially the mechanism in pyroptosis process of UC. Clinical mucosal sample and dextran sulfate sodium (DSS)-induced colitis mouse were used to reveal the association between PCM1 and intestinal inflammation. Intestinal epithelial cell-specific PCM1-knockout mice were constructed to determine the role of PCM1 in colitis. Finally, PCM1 RNA interference and overexpression assays in THP1 cells were employed to study the molecular mechanisms of PCM1 in inflammatory responses and pyroptosis. We found that PCM1 expression was upregulated in the colonic mucosa of UC patients and positively correlated with inflammatory indicators. PCM1 expression was elevated in DSS-induced colitis mice and was reduced after methylprednisolone treatment. In the DSS colitis model, intestinal-specific PCM1-knockout mice exhibited milder intestinal inflammation and lower pyroptosis levels than wild-type mice. In cell level, PCM1 exerted a proinflammatory effect by activating the NLRP3 inflammasome and triggering subsequent gasdermin D-mediated pyroptosis to release IL-1ß and IL-18. In conclusion, PCM1 mediates activation of the NLRP3 inflammasome and gasdermin D-dependent pyroptosis, ultimately accelerating intestinal inflammation in UC. These findings revealed a previously unknown role of PCM1 in initiating intestinal mucosal inflammation and pyroptosis in UC, and this factor is expected to be a regulator in the complex inflammatory network of UC.

[Changes in the expression of genes related to intestinal fatty acid oxidation and carnitine metabolism in patients with ulcerative colitis].

Objective: To investigate the changes in gene expression related to intestinal fatty acid oxidation and carnitine metabolism in patients with ulcerative colitis (UC). Methods: A retrospective study was conducted involving patients with UC (UC group) and non-UC controls (control group) who underwent routine colonoscopy to exclude polyps at Peking Union Medical College Hospital between January 1, 2018, to December 31, 2023. Colon tissue samples were collected from both groups and RNA was extracted. Real-time fluorescence quantitative polymerase chain reaction technology was used to detect the mRNA expression levels of genes related to fatty acid oxidation and carnitine metabolism and to analyze their correlation with inflammatory gene expression. The expression of genes linked to fatty acid oxidation and carnitine metabolism was analyzed by analyzing the colonic mucosal transcriptome data of UC patients and controls in high-throughput gene expression database (GEO). Immunohistochemistry was used to examine the expression of the carnitine transporter SLC6A14 in the intestinal tissues of both groups at the protein level. Eight-week-old male C57BL/6 mice were selected and divided into a drinking water group (drinkind daily water) and a dextran sodium sulfate (DSS) group (drinking 2.5% DSS solution) with 4 mice in each group. DSS was used to induce an acute colitis model in mice and detect the difference in mRNA expression levels of SLC6A14 and interleukin-6 (IL-6) in the intestinal tissues of the both groups of mice. Results: A total of 22 patients were included in the UC group, with 12 males and 10 females, aged 16-64 (40±12) years. The control group consisted of 10 patients, with 3 males and 7 females, aged 43-72 (64±8) years. The UC group had lower mRNA expression levels of genes related to fatty acid oxidation and transport in the intestine compared to those in the control group, such as CD36 [0.40 (0.27, 0.55) vs 0.93 (0.39, 2.93)], CPT1A [0.39 (0.07, 0.54) vs 0.93 (0.41, 1.71)], CPT1B (0.37±0.36 vs 1.37±0.89), CPT2 [0.36 (0.30, 0.43) vs 1.14 (0.68, 1.34)], CRAT [0.31 (0.25, 0.41) vs 1.06 (0.64, 1.73)], CROT [0.14 (0.10, 0.21) vs 0.95 (0.77, 1.27)] (all P<0.05). The mRNA expression levels of genes related to carnitine transport in the UC group were lower than those in the control group, such as OCTN1 [0.18 (0.10, 0.41) vs 0.83 (0.41, 1.47)], OCTN2 [0.01 (0.00, 0.01) vs 0.47 (0.35, 2.15)] (both P<0.05). The mRNA expression levels of the carnitine transporter gene SLC6A14 in the intestine of UC patients was higher than that of the control group [11.31 (5.34, 23.50) vs 0.78 (0.07, 3.70), P<0.001], and showed a positive correlation with the inflammatory gene IL-6 (r=0.425, 95%CI: 0.076-0.681, P=0.019). Analysis of the GEO database revealed lower expression levels of CD36, CPT1A, CPT2, CRAT and CROT in UC group compared to controls (all P<0.05), while the expression levels of SLC6A14 were higher than those in control group (P<0.05). The protein expression level of SLC6A14 in colon tissue of UC group was higher than that of control group (0.45±0.07 vs 0.30±0.01, P=0.019). The mRNA expression of SLC6A14 in the intestine of DSS group was higher compared to that in the drinking water group (1.83±0.90 vs 0.60±0.10, P=0.035). Conclusion: The expression levels of genes associated with intestinal fatty acid oxidation and carnitine metabolism (CD36, CPT1A, CPT1B, CPT2, CRAT, CROT, OCTN1, and OCTN2) are decreased in UC patients, while the expression level of SLC6A14, a gene capable of transporting both amino acids and carnitine, is increased.

[Effect of Modified Xiaoyao Powder on intestinal barrier and intestinal flora in mice with metabolic associated fatty liver disease based on "gut-liver axis"].

This study explores the effects and mechanisms of Modified Xiaoyao Powder on the intestinal barrier and intestinal flora in mice with metabolic associated fatty liver disease(MAFLD) based on the " gut-liver axis". Sixty male C57BL/6 mice were randomly divided into the normal group, model group, bifidobacterium tetrad tablet group(SQ), and Modified Xiaoyao Powder groups with low,medium and high doses(XL, XM, XH), with 10 mice in each group. All the mice were administrated with a high-fat diet to build the MAFLD model except the normal group and then treated with related drugs for 12 weeks. Body mass, liver wet weight, and liver index were detected. Serum aspartate aminotransferase(AST), alanine aminotransferase(ALT), total cholesterol(TC), triacylglycerol(TG), low density lipoprotein cholesterol(LDL-C), high density lipoprotein cholesterol(HDL-C), and lipopolysaccharide(LPS)levels were detected using the biochemical kits. The contents of tumor necrosis factor-α(TNF-α) and interleukin(IL-6) in the liver were tested simultaneously. The morphological changes of the liver and intestine were observed using hematoxylin-eosin(HE) staining and oil red O staining. The goblet cells in the ileum were detected by periodic acid Schiff and alcian blue stain(AB-PAS) staining.The expression of zonula occludens-1(ZO-1), recombinant occludin(occludin), and recombinant claudin 1(claudin-1) in ileum and colon were detected by immunohistochemistry and Western blot. The changes of intestinal flora in mice were analyzed by 16S rRNA gene sequencing. The results showed that compared with the normal group, body weight, liver wet weight and liver index in the model group increased. The contents of TC, TG, ALT, AST, LDL-C, and LPS in the serum of the model group increased, while HDL-C decreased. Meanwhile, the contents of TNF-α and IL-6 in liver tissue increased and liver lipid accumulation increased, indicating successful model induction. Compared with the model group, body weight, liver wet weight, and liver index were decreased in XM,XH groups and SQ group. Serum levels of TC, TG, LDL-C, ALT and AST in XM group and SQ group were significantly decreased,and HDL-C levels were increased. The levels of IL-6, TNF-α in liver tissue and serum LPS in the XL, XM groups and SQ group were significantly decreased. The protein expression of claudin-1, occludin and ZO-1 in XL, XM groups and SQ group were increased. The analysis of intestinal flora showed that compared with the model group, Modified Xiaoyao Powder with a medium dose could significantly improve the richness and diversity of intestinal flora in mice. At the phylum level, the Firmicutes/Bacteroidetes(F/B) ratio decreased; at the genus level, Lactobacillus, Brautella, Bacteroides, and Ackermannia increased, while Prevotella, Desulfovibrio and Turicibacter decreased. The main differential species were Odorbacteraceaeae and Peptostreptococcaceae. In conclusion, Modified Xiaoyao Powder could inhibit inflammation, regulate intestinal flora homeostasis, and promote the repair of the intestinal mucosal barrier in mice with MAFLD.

[Effect of Sijunzi Decoction on intestinal barrier of type 2 diabetic mice].

This study aims to explore the improvement effect of Sijunzi Decoction on intestinal barrier in diabetic mice. A type 2 diabetes mellitus(T2DM) model was established in C57BL/6J mice by feeding them with high-sugar and high-fat diet combined with streptozotocin(STZ). The T2DM mice were randomly divided into a control group, a T2DM group, a donepezil(DON) group, a rosiglitazone(RGZ) group, and Sijunzi Decoction groups(7. 5, 15, and 30 g·kg~(-1)), and orally administered for six weeks. The body weight and fasting plasma glucose(FBG) of mice were recorded. Fasting plasma insulin(FINS) and insulin resistance index(HOMA-IR) were observed to assess insulin resistance(IR). Intestinal flora and levels of serotonin(5-HT), lipopolysaccharide(LPS), and short-chain fatty acids(SCFAs) in serum were analyzed. Changes in colonic structure and tight junction proteins occludin, claudin-1,and ZO-1 were observed through HE staining and immunohistochemistry. Spontaneous alternation test was conducted to observe the effect on spatial memory ability. Compared with the results in the control group, FBG and HOMA-IR in the T2DM group were significantly increased(P< 0. 01); species richness index(Sobs index), Shannon diversity index(Shannon index), and species abundance estimate index(Chao index) were decreased; LPS was significantly increased(P< 0. 001), while the levels of 5-HT,SCFAs, occludin, claudin-1, and ZO-1 were significantly decreased(P< 0. 01), indicating impaired colonic barrier function;spontaneous alternation accuracy was significantly decreased(P<0. 05). After 6 weeks of Sijunzi Decoction treatment, compared with the results in the T2DM group, FBG and HOMA-IR in the Sijunzi Decoction 15 g·kg~(-1) group were significantly decreased(P<0. 01);Sobs index, Shannon index, and Chao index were increased; LPS was significantly decreased(P<0. 01), while the levels of 5-HT,SCFAs, occludin, claudin-1, and ZO-1 were significantly increased(P< 0. 05), indicating improved colonic barrier function;spontaneous alternation accuracy was increased(P<0. 001). In conclusion, Sijunzi Decoction has the effect of improving intestinal barrier in diabetic mice.

Oxymatrine alleviates NSAID-associated small bowel mucosal injury by regulating MIP-1/CCR1 signalling and gut microbiota.

Oxymatrine (OMT) as a quinazine alkaloid extracted from matrine has been shown to exhibit anti-inflammatory and anti-tumour effects. However, the protective mechanism of OMT on NSAID-associated small bowel mucosal injury remains unreported. We found that OMT could improve the clinical symptoms and pathological inflammation scoring, reduce the secretion of proinflammatory cytokines IL-1ß, IL-6 and TNF-α and cell apoptosis, promote cell proliferation and protect intestinal mucosal barrier as compared with the Diclofenac Sodium (DS) group. Further RNA-seq and KEGG analysis uncovered that the differentially expressed genes between DS and control groups were mainly enriched in immune regulation, of which MIP-1γ and its receptor CCR1 expression were validated to be repressed by OMTH. MAPK/NF-κB as the MIP-1 upstream signalling was also inactivated by OMT treatment. In this study, OMT regulated gut microbiota. Venn diagrams visualized and identified 1163 shared OTUs between DS group and OMTH group. The results showed that the α diversity index in the DS group was lower than that in the OMTH group, indicating that the complexity of the flora was reduced in the intestinal inflammatory state. ß diversity mainly includes Principal Component Analysis (PCA) and Principal Co-ordinates Analysis (PCoA). The differences between groups can be observed through PCA. The more similar the composition of the flora, the closer the samples are. We found that the difference was smaller in the DS group than in the OMTH group. The results of PcoA showed that the sample similarity between OMTH groups was the highest. Moreover, gut microbiota analysis unveiled that the abundances of Ruminococcus 1, Oscillibacter and Prevotellaceae at the genus level as well as Lactobacillus SP-L-Yj at the species level were increased in OMTH group as compared with the DS group but the abundance of Allobaculum, Ruminococceos-UCG-005, Ruminococceos-NK4A214 and Clostridium associated with DS-induced small bowel mucosal injury could be decreased by OMTH. MIP-1α and CCR1 were upregulated in human small bowel injury samples as compared with the normal ileal mucosa tissues. In conclusion, our findings demonstrated that OMT could alleviate NSAID-associated small bowel mucosal injury by inhibiting MIP-1γ/CCR1 signalling and regulating gut microbiota.

Mitigation effects of plant carbon black on intestinal morphology, inflammation, antioxidant status, and microbiota in piglets challenged with deoxynivalenol.

Introduction: Plant carbon black (PCB) is a new feed additive for zearalenone adsorption in China. However, information regarding whether PCB can effectively absorb deoxynivalenol (DON) is limited. Methods: To explore this research gap, the present study examined the adsorption effectiveness of DON by PCB using a phosphate buffer, artificial gastric juice, and artificial intestinal juice. In a 21-day in vivo trial, 48 male piglets were randomly assigned to four treatment groups: (1) uncontaminated basal diet (CTR), (2) basal diet supplemented with 1 mg/kg PCB(PCB), (3) 2.3 mg/kg DON-contaminated diet (DON), and (4) 2.3 mg/kg DON-contaminated diet supplemented with 0.1% PCB (DON+PCB). Results: When DON concentration was 1 µg/mL, the adsorption rate of PCB on DON in phosphate buffer systems (pH 2.0 and 6.0) and the artificial gastric and intestinal juices were 100%, 100%, 71.46%, and 77.20%, respectively. In the in vivo trial, the DON group significantly increased the DON+deepoxy-deoxynivalenol (DOM-1) content in serum as well as the inflammation cytokine proteins (interleukin-6, interleukin-8, and tumor necrosis factor-α) and mRNA expression of interleukin-6 and longchain acyl-CoA synthetase 4 in the jejunum and ileum. It decreased the villus height, goblet cells, mucosal thickness, and mRNA expression of Claudin-1 compared to the CTR group. In addition, DON decreased the Shannon and Simpson indices; reduced the relative abundances of Firmicutes, Lactobacillus, Candidatus_Saccharimonas, and Ruminococcus; and increased the relative abundances of Terrisporobacter and Clostridium_sensu_stricto_1 in the cecal content. Discussion: In conclusion, these results suggest that PCB showed high adsorption efficacy on DON in vitro, and exhibit the protective effects against various intestinal toxicity manifestations in DON-challenged piglets.