Dextran Sulfate Sodium Treatment Research Articles

Toll-like receptor 4 deficiency ameliorates experimental ileitis and enteric neuropathy: Involvement of nitrergic and 5-hydroxytryptaminergic neurotransmission.

Inflammatory bowel disease (IBD) patients display genetic polymorphisms in toll-like receptor 4 (TLR4) genes, contributing to dysregulate enteric nervous system (ENS) circuits with increased levels of 5-HT and alteration of the neuroimmune crosstalk. In this study, we investigated the impact of TLR4 signalling on mouse ENS dysfunction caused by dextran sulphate sodium (DSS)-induced ileitis. Male C57BL/6J (wild-type [WT]) and TLR4-/- mice (10 ± 2 weeks old) received 2% DSS in drinking water for 5 days and then were switched to 3-day regular drinking water. Histological analysis and proinflammatory cytokine mRNA levels were assessed in ileal samples. Gut motility was evaluated by changes in transit of a fluorescent-labelled marker and isometric neuromuscular responses of ileal full-thickness segments to receptor and non-receptor-mediated stimuli. Alterations in ENS architecture were assessed by confocal immunohistochemistry in longitudinal muscle-myenteric plexus whole-mount preparations. In WT mice, DSS treatment caused delayed gastrointestinal transit, ileal myenteric neurodegeneration, reactive gliosis and release of proinflammatory cytokines. Enhanced cholinergic and tachykinergic excitatory tone, increased inducible nitric oxide synthase (iNOS)-mediated relaxation, and changes in 5-HT2A and 5-HT3 receptor-mediated responses were observed during ileitis in WT mice. TLR4 deficiency reversed most of the functional and morphological abnormalities. Our results demonstrate that TLR4 activity influences the severity of ileitis, neuroglial plasticity, gut motility, and nitrergic and 5-HTergic neurotransmissions. The neuroimmune interaction between TLR4 and 5-HT observed in our study appears to be a potential pharmacological target to treat ENS dysfunction implicated in IBD onset/progression.

Microbiota translocation following intestinal barrier disruption promotes Mincle-mediated training of myeloid progenitors in the bone marrow.

Impairment of the intestinal barrier allows the systemic translocation of commensal bacteria, inducing a proinflammatory state in the host. Here, we investigated innate immune responses following increased gut permeability upon administration of dextran sulfate sodium (DSS) in mice. We found that Enterococcus faecalis translocated to the bone marrow following DSS treatment and induced trained immunity (TI) hallmarks in bone-marrow-derived mouse macrophages and human monocytes. DSS treatment or heat-killed E.faecalis reprogrammed bone marrow progenitors (BMPs), resulting in enhanced inflammatory responses invitro and invivo and protection against subsequent pathogen infections. The C-type lectin receptor Mincle (Clec4e) was essential for E.faecalis-induced TI in BMPs. Clec4e-/- mice showed impaired TI upon E.faecalis administration and reduced pathology following DSS treatment. Thus, Mincle sensing of E.faecalis induces TI that may have long-term effects on pathologies associated with increased gut permeability.

Chang-Wei-Qing Combined with PD-1 Inhibitor Alleviates Colitis-Associated Colorectal Tumorigenesis by Modulating the Gut Microbiota and Restoring Intestinal Barrier

Chang-Wei-Qing (CWQ) is a widely recognized Traditional Chinese Medicine (TCM) formulation composed of Astragalus, Codonopsis, Atractylodes, Poria, Coix seed, Akebia trifoliata Koidz, Sargentodoxa cuneata, and Vitis quinquangularis Rehd. This formulation has garnered significant interest for its positive effects in mitigating colorectal cancer, and when combined with PD-1, it affects some gut microbiota associated with tumor infiltrating lymphocytes cells. However, the biological rationale underlying the suppression of colitis-associated colorectal cancer (CAC) in AOM/DSS-treated mice by CWQ combined with PD-1 inhibitor remains to be explored. Our aim is to explore the chemopreventive effect of CWQ combined with PD-1 inhibitor on CAC, with a focus on modulating the gut microbiota. A mouse model of CAC was established using azoxymethane (AOM) and dextran sulfate sodium (DSS) treatment. Pathological evaluation of tissue samples included immunohistochemistry and hematoxylin and eosin staining. Intestinal barrier function was assessed by transmission electron microscopy. Fecal microbiota and metabolites were analyzed through 16 S rRNA gene sequencing and liquid chromatography-mass spectrometry, respectively. Mice treated with antibiotics served as models for fecal microbiota transplantation. CWQ combined with PD-1 inhibitor suppressed CAC in AOM/DSS-treated mice. This combined therapy effectively alleviated gut dysbiosis in the CAC model by increasing microbial diversity, enriching probiotic populations such as Limosilactobacillus and Bifidobacterium, and reducing pathogenic bacteria like Desulfovibrio. Additionally, CWQ combined with PD-1 inhibitor downregulated metabolites associated with the NF-kappa B signaling pathway. The combined treatment also significantly improved intestinal barrier function in CAC mice. Transmission electron microscopy of the CWQ combined with PD-1 inhibitor group showed enhanced cellular integrity, a relatively normal mitochondrial structure with intact membranes, and a more abundant, unexpanded endoplasmic reticulum, underscoring the protective effects of this combination on intestinal barrier integrity. Transcriptomic analysis further demonstrated that the combined therapy upregulated genes involved in tight and adherens junctions, while downregulating genes linked to innate immune responses. CWQ combined with PD-1 inhibitor can ameliorate dysbiosis in the AOM/DSS mouse model, with the metabolites of the gut microbiome potentially possessing anti-inflammatory activity. Moreover, CWQ combined with PD-1 inhibitor improves intestinal barrier function, thereby effectively inhibiting the occurrence and development of CAC.

Citrus rhoifolin alleviated DSS-induced acute colitis by activating CEMIP/SLC7A11-mediated cystine uptake and inhibiting epithelial ferroptosis.

Pharmacological inhibition of ferroptosis, a specific form of regulated cell death, has emerged as a promising therapeutic strategy for alleviating symptoms and enhancing endoscopic outcomes in patients suffering from ulcerative colitis. Rhoifolin, a prominent bioactive constituent abundant in the widely consumed fruit Citrus grandis (grapefruit), has garnered attention for its ability to diminish the levels of reactive oxygen species (ROS), which are key inducers of ferroptosis across diverse cellular contexts. In this study, we aimed to investigate whether rhoifolin exerts its beneficial effects on colitis by modulating the process of epithelial ferroptosis. Colitis model was successfully established in C57BL/6 mice through the administration of 2.5% dextran sulfate sodium (DSS) solution for a duration of 9days, which was freely accessible for drinking. RNA sequencing was conducted to delve into the mechanisms underlying the rhoifolin-mediated effects on colitis. To evaluate the impact of rhoifolin on ferroptosis in epithelial cells, several key indicators were measured, including mitochondrial morphology, colonic glutathione (GSH) levels, lipid peroxidation product contents, and ROS levels. The results indicated that rhoifolin exhibited profound anti-colitis properties and effectively curbs ferroptosis in epithelial cells of mice subjected to DSS treatment. The RNA sequencing analysis further revealed that rhoifolin stimulated a remarkable upregulation of colonic cell migration-inducing protein (CEMIP) expression by approximately 2.4-fold in colitis-affected mice. Notably, depletion of CEMIP significantly blocked the rhoifolin-induced increase in the cystine transporter solute carrier family 7 member 11 (SLC7A11, from 1.9-fold to approximately 1.1-fold), as well as the elevation of cystine uptake (from 1.72-fold to 1.2-fold) and glutathione (GSH) biosynthesis (from 2.1-fold to 1.2-fold), and the suppression of epithelial ferroptosis (from 0.51-fold to 0.94-fold) in mice with colitis. Molecular docking investigations have pinpointed crucial amino acid residues within CEMIP, specifically His267, His289, and Phe265, as the primary interaction sites (docking score: -7.8kcal/mol), facilitating the engagement of rhoifolin via hydrogen bonding interactions. Rhoifolin significantly mitigated DSS-induced colitis primarily through inhibiting epithelial ferroptosis. The activation of CEMIP by citrus-derived rhoifolin led to a notable upregulation of SLC7A11 expression, thereby enhanced cystine uptake and facilitated GSH biosynthesis, ultimately suppressed the occurrence of ferroptosis in epithelial cells.

Leucine-Enriched Diet Reduces Fecal MPO but Does Not Protect Against DSS Colitis in a Mouse Model of Crohn's Disease-like Ileitis.

Understanding the complex link between inflammation, gut health, and dietary amino acids is becoming increasingly important in the pathophysiology of inflammatory bowel disease (IBD). This study tested the hypothesis that a leucine-rich diet could attenuate inflammation and improve gut health in a mouse model of IBD. Specifically, we investigated the effects of a leucine-rich diet on dextran sulfate sodium (DSS)-induced colitis in germ-free (GF) SAMP1/YitFC (SAMP) mice colonized with human gut microbiota (hGF-SAMP). hGF-SAMP mice were fed one of four different diets: standard mouse diet (CHOW), American diet (AD), leucine-rich AD (AD + AA), or leucine-rich CHOW diet (CH + AA). Body weight, myeloperoxidase (MPO) activity, gut permeability, colonoscopy scores, and histological analysis were measured. Mice on a leucine-rich CHOW diet showed a decrease in fecal MPO prior to DSS treatment as compared to those on a regular diet (p > 0.05); however, after week five, prior to DSS, this effect had diminished. Following DSS treatment, there was no significant difference in gut permeability, fecal MPO activity, or body weight changes between the leucine-supplemented and control groups. These findings suggest that while a leucine-rich diet may transiently affect fecal MPO levels in hGF-SAMP mice, it does not confer protection against DSS-induced colitis symptoms or mitigate inflammation in the long term.

Probiotic and Rice-Derived Compound Combination Mitigates Colitis Severity.

This study investigated the ability of Enterococcus lactis (E. lactis) and Hasawi rice protein lysate (HPL) to suppress colitis induced by dextran sulfate sodium (DSS) in miceColitis is characterized by inflammation of the colon, and exploring potential therapeutic agents could lead to improved management strategies. Male mice were subjected to DSS treatment to induce colitis, followed by supplementation with E. lactis and/or HPL. The study assessed various parameters, including disease activity index (DAI) scores, gut permeability measured using FITC-dextran, and superoxide dismutase (SOD) activity in excised colon tissues from both treated and untreated control groups. E. lactis supplementation significantly alleviated DSS-induced colitis, as evidenced by improved DAI scores and enhanced gut permeability. Notably, E. lactis combined with HPL (0.1 mg/108) exhibited superior tolerance to a 0.5% pancreatin solution compared to E. lactis alone. Both E. lactis and the combination treatment significantly increased SOD activity (5.6 ± 0.23 SOD U/mg protein for E. lactis and 6.7 ± 0.23 SOD U/mg protein for the combination) relative to the Azoxymethane (AOM)/DSS group, suggesting a reduction in oxidative stress. Additionally, pro-inflammatory markers were significantly reduced in the group receiving both E. lactis and HPL compared to the E. lactis-only group. Levels of proteins associated with cell death, such as PCNA, PTEN, VEGF, COX-2, and STAT-3, were significantly decreased by 14.8% to 80% following E. lactis supplementation, with the combination treatment showing the most pronounced effects. These findings suggest E. lactis supplementation may be beneficial for colitis, with HPL potential to enhance its effectiveness.

Thalidomide mitigates Crohn's disease colitis by modulating gut microbiota, metabolites, and regulatory T cell immunity

Thalidomide (THA) is renowned for its potent anti-inflammatory properties. This study aimed to elucidate its underlying mechanisms in the context of Crohn’s disease (CD) development. Mouse colitis models were established by dextran sulfate sodium (DSS) treatment. Fecal microbiota and metabolites were analyzed by metagenomic sequencing and mass spectrometry, respectively. Antibiotic-treated mice served as models for microbiota depletion and transplantation. The expression of Forkhead box P3+ (FOXP3+) Regulatory T cells (Tregs) was measured by flow cytometry and immunohistochemical assay in colitis model and patient cohort. THA inhibited colitis in DSS–treated mice by altering the gut microbiota profile, with an increased abundance of probiotics Bacteroides fragilis (Bf), while pathogenic bacteria were depleted. In addition, THA increased beneficial metabolites bile acids and significantly restored gut barrier function. Transcriptomic profiling revealed that THA inhibited interleukin-17 (IL17), IL1β and cell cycle signaling. Fecal microbiota transplantation from THA-treated mice to microbiota-depleted mice partly recapitulated the effects of THA. Specifically, increased level of gut commensal Bf was observed, correlated with elevated levels of the microbial metabolite 7-Ketolithocholic acid (7-KA) following THA treatment. This microbial metabolite may stable FOXP3 expression by targeting the bile acid receptor farnesol X receptor 1(FXR1) to inhibit autophagy. An interaction between FOXP3 and FXR1 was identified, with binding regions localized to the FOXP3 domain (aa 238-335) and the FXR1 domain (aa 82-222), respectively. Conclusively, THA modulates the gut microbiota and metabolite profiles towards a more beneficial composition, enhances gut barrier function, promotes the differentiation of FOXP3+ Tregs and curbs pro-inflammatory pathways.

Blood pressure alteration associated with abnormal body electrolyte and water balance in colitis mice.

Previous studies reported that there is an association between abnormal body fluid balance and prognosis in colitis patients. However, it remains to be clarified the effects of colitis on characteristics of body electrolytes or water content, including alternation in blood pressure. In this study, we examined the effects of colon injury on body water balance and blood pressure in the dextran sodium sulfate (DSS)-induced colitis mouse model. We evaluated body electrolytes and water content, blood pressure, and urea-associated water conservation in DSS mice. By 5 days after the treatment, DSS mice exhibited diarrhea but relatively maintained body weight and total body sodium, potassium, and water content by increases in water intake and hepatic ureagenesis. On 7 days after DSS treatment, when colitis becomes severe, DSS mice significantly decreased food and water intake, and body weight but significantly increased relative total body sodium, potassium, and water content per dry mass. Notably, DSS induced more total body dry mass loss relative to water loss. These body electrolytes and water accumulation on day 7 were associated with a reduction in urinary osmole excretion and urine volume accompanied by renal urea accumulation. DSS mice significantly increased blood pressure by day 5 and then decreased on day 7. These findings suggest that body electrolyte and fluid imbalance and alternations in blood pressure in colitis vary with the stage and severity of the condition. Assessment and correction of electrolyte and water content at the tissue level would be important to improve the prognosis of colitis.

Lactobacillus johnsonii colonizing in mice intestine contributes to control the gut barrier function via regeneration of the crypt in DSS‐treated mice

AbstractBackgroundUnbalanced gut microbiota is considered to cause dysfunction of the gut barrier function. Lactobacillus johnsonii MG, isolated from mouse feces as gut associating lactobacilli, enhanced gut barrier function in Caco‐2 cells via interaction with JAM‐2 in tight junctions. In this study, the anti‐inflammatory effects of L. johnsonii MG were investigated in a colitis mouse model developed by treating mice with 3% dextran sulfate sodium (DSS) for 9 days.ResultsMG treatment of colitis mice resulted in fast recovery of the body weight and showed significant improvement in the disease activity index and histopathological scores. The histomorphological score increased by DSS treatment was significantly improved in the MG‐treated group. In the intestine, the expression of Ocln, Zo1, Itga6, Lama3, and Jam2 genes, which are involved in tight junction functions, were significantly upregulated in MG‐treated colitis mice. In the microflora analysis, the abundance of Ruminococcaceae, Bacteroides, and Lachnospiraceae were reduced in DSS‐treated mice and recovered by MG treatment.ConclusionWe reported the potential of L. johnsonii MG in the regeneration of crypts and integrity of matrix proteins in the gut of mice with colitis through its association with tight junctions. The experimental results provide new insights into the probiotic effect of tight junction associating L. johnsonii MG.

Abstract Tu022: Gut-derived bacterial metabolites promote cardiac inflammation, leading to heart failure in murine model of DSS-induced colitis

Background: Inflammatory Bowel Disease (IBD) affects millions of people all over the world. This has been known to contribute to several other comorbidities. Recently, impaired gut-barrier permeability has been known to contribute to cardiovascular diseases in IBD patients. However, the precise mechanisms remain unclear. In this study, we propose that bacterial metabolites, like peptidoglycan, may play a role in promoting cardiac inflammation and ultimately leading to heart failure in mice following colitis. Methods: We induced colitis in C57 black mice with DSS (dextran sodium sulfate) treatment. Further, we collected fecal sample for 16s rRNA analysis to evaluate microbial flora. Additionally, heart and intestine tissues were collected to determine inflammatory genes expression (qPCR), immune cell infiltration (FACS), and intestinal permeability (WB and immunohistochemistry). Blood was collected to quantify the circulating peptidoglycan (PGN) level. The effect of PGN on NFkB inflammatory pathways was evaluated in macrophages. Results: Echo-data showed cardiac dysfunction in DSS mice. Masson’s trichrome staining showed deteriorated intestinal villi, while western blot data indicated decreased Occludin and increased PV-1 level, suggesting a leaky gut in DSS treated mice. Comparative analysis of 16s rRNA sequencing data showed significantly altered Firmicutes/Bacteroidetes ratio in DSS treated mice as compared to control mice. Moreover, plasma PGN level was significantly increased 3 weeks following DSS treatment. Real-time gene expression data of pro-inflammatory cytokines (TNFα) and fibrosis associated genes (col1α1, fibronectin) were increased in DSS mice heart. Increased CD68 expression in the immunostaining data of DSS mice heart suggests the recruitment of inflammatory macrophages. At the molecular level, CDK9 expression was significantly increased in macrophage following PGN treatment, which ultimately leads to an increase in NFkB signaling. Finally, CDK9 inhibition attenuated PGN-induced NFkB signaling. Conclusion: Together, our study suggests that colitis-induced gut leakage leads to CDK9-mediated NFκB upregulation, contributing to cardiac inflammation. Ongoing research will shed light on the underlying molecular mechanisms of cardiovascular dysfunction.

Potential of using an engineered indole lactic acid producing Escherichia coli Nissle 1917 in a murine model of colitis

The gut microbiome is a significant factor in the pathophysiology of ulcerative colitis (UC), prompting investigations into the use of probiotic therapies to counter gastrointestinal inflammation. However, while much attention has been given to the therapeutic potential of microbes at the species and strain level, the discovery and application of their metabolic products may offer more precise and controlled solutions in battling disease. In this work, we examined the therapeutic potential of indole lactic acid (ILA) to alleviate inflammation in a murine model of colitis. A previously constructed ILA-producing Escherichia coli Nissle 1917 strain (EcN aldh) and its isogenic non-ILA producing counterpart (EcN) were studied in a murine model of Dextran Sodium Sulfate (DSS) induced colitis. The colitic animals suffered from severe colitic symptoms, with no differentiation between the groups in body weight loss and disease activity index. However, three days after cessation of DSS treatment the EcN aldh–treated mice showed signs of reduced intestinal inflammation, as manifested by lower concentrations of fecal lipocalin-2. Additionally, expression analysis of the inflamed tissue revealed distinct effects of the EcN aldh strain on proteins associated with intestinal health, such as TFF3, occludin and IL-1β expression. These results show no impact of EcN or EcN aldh on acute DSS-induced colitis, but suggest that in particular EcN aldh may assist recovery from intestinal inflammation.

Iron regulatory protein 2 contributes to antimicrobial immunity by preserving lysosomal function in macrophages

Colorectal cancer and Crohn's disease patients develop pyogenic liver abscesses due to failures of immune cells to fight off bacterial infections. Here, we show that mice lacking iron regulatory protein 2 (Irp2), globally (Irp2-/-) or myeloid cell lineage (Lysozyme 2 promoter-driven, LysM)-specifically (Irp2ΔLysM), are highly susceptible to liver abscesses when the intestinal tissue was injured with dextran sodium sulfate treatment. Further studies demonstrated that Irp2 is required for lysosomal acidification and biogenesis, both of which are crucial for bacterial clearance. In Irp2-deficient liver tissue or macrophages, the nuclear location of transcription factor EB (Tfeb) was remarkably reduced, leading to the downregulation of Tfeb target genes that encode critical components for lysosomal biogenesis. Tfeb mislocalization was reversed by hypoxia-inducible factor 2 inhibitor PT2385 and, independently, through inhibition of lactic acid production. These experimental findings were confirmed clinically in patients with Crohn's disease and through bioinformatic searches in databases from Crohn's disease or ulcerative colitis biopsies showing loss of IRP2 and transcription factor EB (TFEB)-dependent lysosomal gene expression. Overall, our study highlights a mechanism whereby Irp2 supports nuclear translocation of Tfeb and lysosomal function, preserving macrophage antimicrobial activity and protecting the liver against invading bacteria during intestinal inflammation.

Effects of oligosaccharides on performance, intestinal morphology, microbiota and immune reactions in laying hens challenged with dextran sodium sulfate

The aim of this study was to determine the effect of oligosaccharide extract from bamboo shoot (BOS) on the performance, intestinal morphology, microbiota and immune reaction of laying hens challenged with dextran sodium sulfate (DSS). Thirty-two White Leghorn hens (480 days old) were divided into 4 groups (8 hens each) with similar mean body weights: C (basal diet), D (basal diet + DSS), B (5 g/kg BOS diet), and BD (5 g/kg BOS diet + DSS). They were administered a single oral dose of 4 mL of distilled water/kg body weight with or without 0.45 g of DSS for 7 consecutive days from the 14th d to the 21st d of the experiment. The important findings were that (1) The egg yolk ratio was decreased by DSS treatment, but it was improved by BOS treatment, which also increased the egg shell ratio. (2) The diversity of intestinal microbiota and relative abundance of 4 bacteria genera were increased by BOS treatment. (3) Intestinal morphology was not affected by DSS and BOS, but the leukocytes accumulation in the liver was increased by DSS treatment and suppressed by BOS treatment. (4) Dietary BOS treatment influenced the mRNA expression of Th-1 and Treg cytokines in the liver and Th-17 cytokines in both intestine and liver of laying hens. These results suggest that BOS may enhance egg quality, Th-1 and Th-17 immune function without causing tissue damage under normal condition, and may suppress the excessive inflammatory responses during inflammation.

Role of Olive Leaf Extract, Mesenchymal Stem Cells or Low Radiation Dose in Alleviating Hepatic Injury in Rats.

This study was conducted to determine the efficacy of mesenchymal stem cells (MSCs) or low-dose gamma radiation (LDR) on liver injury compared to the effect of olive leaf extract as a hepatoprotective agent. Rats were allocated into six groups; group I served as the negative control. Group II received 5% dextran sodium sulfate (DSS) in its drinking water for 1 week. Group III was injected with a single dose of 1 × 106 bone marrow-derived mesenchymal stem cells (BM-MSCs) intravenously. Group IV was treated as in group III after 5% DSS treatment. Group V was given 5% DSS, followed by olive leaf extract (OLE) (1000mg/ kg, oral). Group VI: 5% DSS for 1 week, then was exposed to low-dose gamma radiation (LDR) (0.05Gy). Rats treated with OLE, BM-MSCs, or exposed to LDR exerted significant alleviation in all hepatic biomarkers, significant enhancements in oxidative stress parameters, and improvements in inflammatory biomarkers Interleukin-1 beta (IL-1β) and Interferon gamma (INF-γ) hepatic contents compared with those of the DSS group. Histological pictures emphasized the biochemical findings. BM-MSCs might be a valuable therapeutic approach to overcome hepatic injury. Exposure to LDR provided protective mechanisms that allow the body to survive better.

BPOZ-2-deficient mice exhibit aggravated inflammation-associated tissue damage after acute dextran sodium sulfate or diethylnitrosamine exposure

An excessive inflammatory response plays an important role in pathological tissue damage associated with pathogen infection and tumorigenesis. Blood POZ-containing gene type 2 (BPOZ-2), an adaptor protein for the E3 ubiquitin ligase scaffold protein CUL3, is a negative regulator of the inflammatory response. In this study, we investigated the pathophysiological functions of BPOZ-2 in dextran sodium sulfate (DSS)-induced colon injury and diethylnitrosamine (DEN)-induced liver damage. Our results indicated that BPOZ-2 deficiency increased IL-1β induction after DSS and DEN treatment. In addition, BPOZ-2-deficient mice were more susceptible to DSS-induced colitis. Notably, BPOZ-2 deficiency aggravated DEN-induced acute liver injury. These results revealed that BPOZ-2 protected against pathological tissue damage with a dysregulated inflammatory response.

HOXD10 regulates intestinal permeability and inhibits inflammation of dextran sulfate sodium-induced ulcerative colitis through the inactivation of the Rho/ROCK/MMPs axis

Abstract Ulcerative colitis (UC) has been identified as a severe inflammatory disease with significantly increased incidence across the world. The detailed role and mechanism of HOXD10 in UC remain unclear. In present study, we found that HOXD10 was lowly expressed in UC samples and was notably decreased by dextran sulfate sodium (DSS) administration. Overexpression of HOXD10 dramatically ameliorated DSS-induced UC symptoms, including the loss of weight, increased disease activity index values, and the shortened colon length. Additionally, terminal-deoxynucleoitidyl transferase mediated nick end labeling and immunohistochemistry staining assays showed that HOXD10 overexpression suppressed cell apoptosis and facilitated proliferation of colon tissues after DSS treatment. Moreover, HOXD10 overexpression obviously suppressed DSS-triggered inflammatory response by decreasing the expression level of TNF-α, IL-6, and IL-1β. Furthermore, overexpression of HOXD10 effectively restored the intestinal permeability, thereby alleviating DSS-induced intestinal barrier dysfunction. Mechanistic study demonstrated that HOXD10 significantly reduced the activities of Rho/ROCK/MMPs axis in colon tissues of mice with UC. In conclusion, this study revealed that HOXD10 might effectively improve DSS-induced UC symptoms by suppressing the activation of Rho/ROCK/MMPs pathway.

Kumquat pomace removal of free polyphenol alleviates induced acute enteritis and restores gut microbiota in dextran sodium sulphate‐treated mice

AbstractKumquat pomace non‐extractable polyphenols (KNEP), which contains celobiotics and has anti‐inflammatory and antioxidant effects, are one of the main components in kumquats. We aimed to determine the preventive and inhibitory effects of KNEP on dextran sodium sulphate (DSS)‐induced inflammatory bowel disease (IBD). The disease activity index (DAI) score, H&E staining, high‐throughput sequencing technology, quantitative analysis, ELISA, and western blotting were used to explore the effect of KNEP in an IBD mouse model. The DAI score and H&E staining results showed that compared with the DSS treatment group, the DAI and pathological status of IBD in the DSS + 3% KNEP (low‐dose) and DSS + 6% KNEP (high‐dose) intervention groups were significantly improved. High‐throughput sequencing showed that the composition of the intestinal flora was restored under KNEP, and the abundance of pathogenic bacteria decreased and that of beneficial bacteria increased. Quantitative analysis of short‐chain fatty acids (SCFAs) showed that the SCFAs content in the cecum of IBD mice increased in a dose‐dependent manner. ELISA results showed that KNEP at different doses could inhibit the expression of TNF‐α, IL‐1β, IFN‐γ, and other inflammatory factors, and that 6% KNEP had the most potent inhibitory effect. Western blotting results showed that KNEP inhibited the expression of TLR4, NF‐κB, and NLRP3 in the colon of mice with DSS‐induced colitis in a dose‐dependent manner. These results indicate that KNEP can significantly improve DSS‐induced acute colitis in mice, and the higher the KNEP content, the more pronounced the improvement in IBD.

Cucurbitacin E Alleviates Colonic Barrier Function Impairment and Inflammation Response and Improves Microbial Composition on Experimental Colitis Models.

Cucurbitacins, which are found in a variety of medicinal plants, vegetables and fruits, were known for their diverse pharmacological and biological activities, including anticancer, anti-oxidative and anti-inflammatory effects. Cucurbitacin E, one of the major cucurbitacins, was recently proved to inhibit inflammatory response. To explore the therapeutic effects of cucurbitacin E on colitis and the underlying mechanisms, male mice drunk water containing 2.5% dextran sulfate sodium (DSS) to establish colitis model and administrated with cucurbitacin E during and after DSS treatment. The disease activity index was scored and colonic histological damage was observed. Intestinal tight junction and inflammatory response were determined. 16S rRNA and transcriptome sequencing were performed to analyze gut microbiota composition and gene expression, respectively. We found that cucurbitacin E alleviated DSS-induced body weight loss and impaired colonic morphology. Cucurbitacin E decreased the expression of inflammatory cytokines and cell apoptosis, and maintained barrier function. Additionally, cucurbitacin E retrieved DSS-induced alterations in the bacterial community composition. Furthermore, a variety of differentially expressed genes (DEGs) caused by cucurbitacin E were enriched in several pathways including the NFκB and TNF signaling pathways as well as in Th17 cell differentiation. There was a close relationship between DEGs and bacteria such as Escherichia-Shigella and Muribaculaceae. Our results revealed that cucurbitacin E may exert protective effects on colitis via modulating inflammatory response, microbiota composition and host gene expression. Our study supports the therapeutic potential of cucurbitacin E in colitis and indicates that gut microbes are potentially therapeutic targets.

Aryl hydrocarbon receptor ligand supplementation impacts colitis-associated depressive-like behavior

Abstract Colitis is an inflammatory bowel disease (IBD) with increased incidences of depression in patients. The mechanisms that define this comorbidity remain poorly understood. Our lab previously showed supplementation with indole-3-carbinol (I3C), an aryl hydrocarbon receptor (AhR) ligand, can reduce disease severity in models of colitis. We aimed to determine the behavioral impact I3C supplementation has on colitis-induced depression via alterations in the gut metabolome. Colitis was induced in using the dextran sodium sulfate (DSS) method and treatment groups were given a regimen of 40 mg/kg I3C as previously reported. Untargeted metabolomic studies revealed quinolinic acid (QA), a metabolite produced by the kynurenine (KYN) pathway and linked to depression, was found to be significantly reduced in I3C-treated mice when compared to colitis controls. To determine the effects of I3C and QA modulation on depressive-like behavior, colitis mice were treated with either I3C or an inhibitor of a major enzyme involved in QA production. Depressive-like behavior was measured using the Tail Suspension Test (TST) method, along with evaluation of neural biomarkers of depression (dopamine, BDNF, GFAP) and stabilization of the blood brain barrier (BBB). Results showed I3C reduced depressive-like behavior and altered select biomarkers associated with depression. These studies provide evidence that AhR can be a potential therapeutic target for both colitis and colitis-associated depression.

Curcumin-mediated alleviation of dextran-induced leaky gut in Drosophila melanogaster.

Aging is commonly characterized by a decline in the physiological functioning of the body organs, with one hallmark being the impairment of intestinal function, leading to increased intestinal permeability known as leaky gut. The aim of this study was to investigate the potential of curcumin to prevent the development of leaky gut in Drosophila melanogaster utilizing the smurf fly method. In this study, flies aged 3-5 days underwent a 10-day dextran sulfate sodium (DSS) treatment to induce intestinal permeability, followed by a smurf assay using brilliant blue dye and locomotor testing the next day. Flies displaying the smurf phenotype were divided into four groups: untreated control and curcumin-treated (10 μM, 50 μM, and 250 μM). After 21 days of treatment, flies were reassessed for the smurf phenotype and underwent locomotor testing. On day 23, flies were subjected to RT-qPCR analysis. By inducing increased intestinal permeability through the administration of DSS, a higher proportion of flies exhibiting the smurf phenotype and a reduced survival rate in the DSS-treated group were observed. Such phenotypes were reversed, decreased number of flies displaying the smurf phenotype and improved fly survival, upon the incorporation of curcumin in the fly food at concentrations of 10, 50, and 250 μM. Subsequent molecular analysis revealed upregulated expression of sod1, cat, and pepck genes, while no significant changes were observed in the expression of sod2, indy, and srl genes following treatment with curcumin at high concentration. Overall, our findings provide insight into the potential effect of curcumin to alleviate the phenotypical features associated with DSS-induced leaky gut, possibly via the selective regulation of aging-related genes.