Mouse Model Of Colitis Research Articles

DOP073 Gli1+ Mesenchymal Cells Drive Intestinal Fibrostenosis by Secreting SMOC2: A Biomarker and Therapeutic Target

Abstract Background Intestinal fibrostenosis in Crohn’s disease (CD) represents a significant clinical challenge, driven by the absence of reliable early biomarkers, limited therapeutic options, and high postoperative recurrence rates, all of which contribute to poor patient outcomes. This study aims to elucidate the role of Gli1+ mesenchymal cells in the pathogenesis of intestinal fibrostenosis and to explore their potential as a novel therapeutic target. Methods CD patients who underwent surgery for intestinal obstruction due to fibrosis were included in this study, and intestinal tissues were collected from both fibrotic and normal sites. Dextrose sodium sulfate (DSS)-induced and 2,4,6-Trinitrobenzenesulfonic acid (TNBS)-induced chronic colitis mouse models and their normal controls were also included. Single-cell RNA sequencing was performed on both human and murine tissues. Gli1-CreERT2; R26-tdTomato mice were generated for lineage tracing. Cell sorting combined with Smart-seq was used to isolate Gli1+ mesenchymal cells, revealing their pathogenic determinants. Results Single-cell RNA sequencing data and immunofluorescence staining from surgical patients revealed an enrichment of Gli1+ mesenchymal cells at fibrotic sites. Lineage tracing of Gli1+ mesenchymal cells demonstrated their proliferation and acquisition of a myofibroblast phenotype following chronic colitis. In vivo ablation of Gli1+ mesenchymal cells attenuated the severity of intestinal fibrosis. Compared to Gli1- cells, Gli1+ mesenchymal cells expressed a distinct gene expression profile, including markers of extracellular matrix (ECM)-related genes and Smoc2 (SPARC Related Modular Calcium Binding 2, encodes an extracellular matrix protein). Elevated Smoc2 expression was confirmed in both human and murine tissues, and Smoc2 knockdown further supported its role in promoting intestinal fibrosis. Mechanistically, Gli1+ mesenchymal cells establish a pro-fibrotic niche through the endocrine and exocrine functions of SMOC2, promoting ECM deposition and the activation of other fibroblasts. Additionally, a predictive and diagnostic model was established by assessing SMOC2 levels in tissue and plasma samples from CD patients with intestinal fibrosis, highlighting its potential as a biomarker for postoperative recurrence and as a therapeutic target. Conclusion Our results demonstrate that Gli1+ mesenchymal cells are key drivers of intestinal fibrostenosis, forming a pro-fibrotic niche through their unique secretion of the SMOC2 protein at fibrotic sites. SMOC2 could therefore be used as a predictive biomarker for postoperative recurrence and as a potential therapeutic target.

P0220 Anti-TNFα, anti-integrin α4β7 and anti-IL23p19 biologic treatment dose optimization in a dextran sodium sulphate (DSS)-induced colitis mouse model

Abstract Background Current immunotherapy for inflammatory bowel disease (IBD) treatment is based on anti-TNFα, anti-integrin α4β7, anti-IL12/IL23 and anti-IL23 antibodies that have demonstrated to be safe and effective. In vivo models are crucial for research with biologics, but the literature on doses of above-mentioned drugs in in vivo IBD models is scarce, highly variable and covers wide ranges. Thus, we aim to find the optimal dose for biologic treatment in a DSS-induced colitis model. Methods C57BL/6 mice were randomized into a control group and treatment groups receiving 3% DSS combined with varying doses of neutralizing antibodies against TNFα, integrin α4β7, and IL-23p19. Treated mice received 3% DSS ad libitum for 5 days and clean water for another 3 additional days (5 + 3 model). Neutralizing antibodies were injected intraperitoneally on days 2 and 5 of the experiment. Doses used for optimization were set for each dose at 100, 250 and 500 μg/mouse for anti-integrin α4β7 and anti-IL23p19 antibodies, and at 10, 25 and 50 μg/mouse for anti-TNFα antibody for covering ranges found in bibliography. Weight loss, fecal consistency and fecal occult blood parameters were measured every day of experiment to elaborate a disease activity index (DAI). Mice were sacrificed at day 8 and the colon was obtained for histological evaluation by H/E staining, and for extraction of lamina propria mononuclear cells (LPMCs). Longitude was also measured. Blood was obtained by intracardiac punction and peripheral blood mononuclear cells (PBMCs) were obtained. Distal and proximal colon sections were fixed in 4% paraformaldehyde and embedded in paraffin. 4 μm sections were hydrated and H/E stained for histological score assessment. Extracted LPMCs and PBMCs were stained for flow cytometry evaluation of inflammation markers. Results Proximal and distal colon of mice treated with two doses of 10 μg/mouse of anti-TNFα, 250 μg/mouse of anti-integrin α4β7 and 100 μg/mouse of anti-IL23p19 showed the greatest tissue conservation and repair (Figure 1). In addition, these groups had less weight loss throughout the experiment as well as a reduced DAI (Figure 2). LPMCs and PBMCs inflammatory markers were also decreased in these groups in comparison with the others. Slight differences were found in 250 and 500 μg/mouse anti-integrin α4β7 treated mice. Conclusion The optimal treatment doses of neutralizing anti-TNFα, anti-integrin α4β7 and anti-IL23p19 antibodies are set at two doses of 10, 250 and 100 μg/mouse respectively for this 5 + 3 model of DSS-induced colitis. By establishing precise dosimetry baselines, our work provides a robust framework for combinatorial therapies, which could unlock novel approaches for IBD treatment.

P1312 Clickable nanozyme enhances colonization of Saccharomyces boulardii by spatiotemporal guidance for ameliorating inflammatory bowel disease

Abstract Background Compelling evidence indicates that dysregulated in the gut microbiota significantly contribute to the progression and pathogenesis of inflammatory bowel disease (IBD). Probiotic therapeutic interventions aimed at modulating the microbiota offer potential alternative approaches for treating IBD, but currently available probiotics often suffer from low intestinal colonization and limited targeting capability. Methods Here, we developed azido (N3)-modified Prussian blue nanozyme (PB@N3) spatio-temporal guidance enhances the targeted colonization of probiotics to alleviate intestinal inflammation. First, IVIS and Photoacoustic imaging demonstrated clickable PB@N3 targets intestinal inflammation, simultaneously, it scavenges reactive oxygen species (ROS). Subsequently, utilizing click chemistry “N3-DBCO” to spatio-temporally guide targeted colonization of dibenzocyclooctyne (DBCO)-modified Saccharomyces boulardii (S.Br@DBCO). The therapeutic effects of PB@N3 + S.Br@DBCO were verified by using the dextran sulfate sodium (DSS)-induced colitis mice model. Weight loss, fecal conditions, colon length and histopathological changes were monitored. Results PB@N3 targets and anchors to inflamed region. The "click" reaction between PB@N3 and S.Br@DBCO has excellent specificity and efficacy both in vivo and in vitro. Despite the complex physiological environment of IBD, "click" reaction can prolong the retention time of probiotics in the intestine. Dextran sulfate sodium (DSS)-induced colitis mice model, demonstrates that the combination of PB@N3 and S.Br@DBCO effectively enhances the colonization of probiotics, restores intestinal barrier function, and alleviates intestinal inflammation. Conclusion This is the first time that “click” chemistry was employed to combine fungal probiotics and nanozyme. PB@N3 spatio-temporal guidance enhances targeted colonization of S.Br@DBCO provides a promising medical treatment strategy for IBD.

P0174 Enteric glial cells-derived NGF prevents necroptosis of intestinal epithelial cells and alleviates DSS-induced colitis

Abstract Background The maintenance and repair of the intestinal epithelial barrier (IEB) is a multifaceted process that requires the coordinated participation of different cell types within the gastrointestinal tract. Studies have shown that ablation of enteric glial cells (EGCs) can lead to intestinal epithelial cell necrosis and destruction of the IEB. However, the specific role of EGCs in it remains ambiguous. The aim of this study was to elucidate the potential role of EGCs in regulating IEB and intestinal inflammation. Methods In this study，we employed immunofluorescence, western blot, ELISA, and gene expression profiling to assess the expression of GFAP (a marker for EGCs), NGF, and necroptosis-associated proteins in intestinal tissues from IBD patients. In addition, DSS-induced colitis mouse models, in vitro co-culture systems, and transcriptomic analysis were used to explore the effects of EGCs and NGF on IECs necroptosis and inflammation. Results In intestinal tissues of IBD patients, reduced expression of GFAP and S100β suggests damage to EGCs. Additionally, we found that NGF in intestinal tissues primarily originates from EGCs. Diminished NGF secretion due to EGCs damage correlates with increased necroptosis of IECs. Exogenous administration of NGF inhibits DSS-induced necroptosis of IECs and alleviates colonic inflammation. Ablation of EGCs exacerbates necroptosis of IECs, disruption of IEB, and intestinal inflammation following DSS treatment. In vitro co-culture experiments demonstrate that EGCs suppress necroptosis of IECs induced by T/S/Z mix. Further flow cytometry and TEM results confirm that NGF effectively mitigates T/S/Z mix-induced necroptosis of IECs.Transcriptomic sequencing indicated that RNF126 is a downstream target in the NGF signaling pathway, potentially mediating the protective effects of EGCs-derived NGF on IECs. Conclusion Based on the findings from this study, it is evident that EGCs play a crucial role in maintaining intestinal homeostasis through their production of NGF. Reduced NGF secretion from damaged EGCs correlates with increased necroptosis of IECs, exacerbating inflammation in colonic tissues. Exogenous NGF administration effectively attenuates this process, highlighting its therapeutic potential in IBD. Furthermore, transcriptomic analysis identified RNF126 as a downstream mediator in the NGF signaling pathway, its specific role remains speculative and requires further investigation to elucidate its mechanistic involvement in mediating the protective effects of NGF. In conclusion, these findings emphasize the intricate interplay between EGCs, NGF signaling, and IEC survival, pointing towards novel therapeutic strategies targeting this pathway in IBD management.

P0895 The Prognostic Significance of Visceral Adiposity indices in conjunction with Plasma Trace Elements in Newly Diagnosed Crohn's Disease

Abstract Background While imbalances in trace elements are recognized for causing dysfunction in adipose tissue and disease onset and progression of CD, the relationship between the initial status of trace elements and the risk of VAT accumulation in patients with CD remains uncertain. This study aims to investigate the prevalence of trace element deficiencies among newly diagnosed CD patients, explore how these deficiencies relate to VAT accumulation, and examine their implications for disease progression. In particular, we focus on magnesium due to its potential therapeutic effects, evaluating its role in experimental colitis models to assess its impact on inflammation and immune responses. Methods The analysis was based on an inception cohort of 300 patients newly diagnosed with CD between July 2019 and June 2022. Plasma trace element levels were measured at baseline. VAT was evaluated using computed tomography (CT) scans obtained at first diagnosis. Patients were followed for a period of two years to monitor outcomes. Logistic regression analyses were performed for statistical assessment. To elucidate magnesium's therapeutic mechanisms, we employed DSS-induced colitis mouse models and conducted in vitro CD4+ T cell activation experiments. Gut microbiota composition was analyzed using 16S rRNA sequencing. Results Deficiency in iron was most prevalent affecting 25.67% of the patients, with zinc deficiency at a rate of 3.67%. An inverse correlation was observed between magnesium levels and VAT index (β=-0.24, p<0.001). Reduced levels of zinc and magnesium were predictive of adverse clinical outcomes (OR=0.51, p=0.002; OR=0.52, p=0.001) and drug outcomes (OR=0.39, p<0.001; OR=0.57, p=0.004). Further stratified analysis revealed that the protecive effect of magnesium was significant exclusively in patients with a VAT-to-subcutaneous adipose tissue ratio (VAT/SAT) ≥1. Magnesium supplementation attenuated colonic inflammation in DSS-induced colitis mouse model, reduced infiltration of CD4⁺T cells, and enhanced gut microbiota diversity. Notably, there was a significant increase in beneficial bacteria, including butyrate-producing genera such as Intestinimonas, Clostridia_UCG-014, and Paludicola. In vitro studies further demonstrated magnesium's capacity to suppress inflammatory cytokine production by CD4⁺ T cells from patients with CD. Conclusion Disruptions in baseline trace elements correlate with poor outcomes in CD patients. The interaction between trace elements and VAT may impact disease progression. Magnesium's therapeutic effects, mediated through immunomodulation and microbiota regulation, highlight its potential as a therapeutic target for personalized treatment approaches in inflammatory bowel disease.

DOP068 Vedolizumab counteracts Parkinson’s disease-related brain pathology driven by gut-primed IBD T cells

Abstract Background The gut-brain axis has been increasingly recognized as a critical pathway linking Inflammatory Bowel Diseases (IBD) with neurodegenerative diseases. Chronic inflammation resulting from IBD can extend beyond the gut, and epidemiological data have also linked to the increased prevalence of neurodegenerative conditions like Parkinson’s disease (PD). However, the exact mechanisms underlying this interconnection are largely unclear. We therefore investigated how gut-primed T cells from IBD patients may drive neurodegenerative processes seen in PD. Methods Peripheral blood T cells from IBD patients were analyzed for co-expression of gut-homing integrin α4β7 and brain-homing integrin β1. Using gut-specific photoconversion in a Kaede T cell Transfer Colitis mouse model, we assessed the infiltration of gut-primed T cells into the brain tissue. To model and elucidate the interplay of T cells with the brain tissue ex vivo, we developed an innovative three-dimensional co-culture system involving human stem cell-derived Brain Organoids (hBrO) and peripheral blood T cells from IBD patients and controls. Vedolizumab, an anti-α4β7 integrin antibody, was used to assess its potential in blocking T cell accumulation and subsequent neurotoxicity in hBrO cultures. Results Gut-primed T cells from IBD patients co-expressed brain-homing integrins, suggesting that they are able to enter brain tissue. Clear evidence of gut-to-brain T cell trafficking was obtained in the Kaede T cell Transfer Colitis mouse model, confirming the capacity of gut-primed T cells to migrate across the blood-brain barrier under conditions of chronic intestinal inflammation. In the hBrO co-culture model, neurons expressed MAdCAM-1, and MAdCAM-1 expression in neurons was also found in single cell RNA sequencing of postmortem brain tissue. Consistently, α4β7+ IBD T cells accumulated specifically in the vicinity of neurons, leading to neuronal cell death and aSyn aggregation (a hallmark of PD) in hBrO. In line, Vedolizumab treatment reduced IBD T cell accumulation in hBrO and preserved neural cell integrity. Conclusion Our data, for the first time, show a T cell trafficking-driven axis of gut-to-brain communication with pathogenic potential for the central nervous system in the context of IBD. Moreover, our findings suggest that neurotoxic T cell-neuron interaction is mediated by MADCAM1 and α4β7 integrin. Thus, our study reveals a novel pathway, by which IBD T cells may contribute to neurodegeneration, linking chronic gut inflammation to brain tissue pathology and synucleinopathy. Blocking α4β7-mediated T cell-induced neurotoxicity and aSyn pathology presents a potential therapeutic approach for IBD patients at risk of neurodegenerative diseases such as PD.

DOP031 Anti-IL-7 receptor plus anti-IL12/23 combination induces complete histological normalization in chronic colitis

Abstract Background The signaling networks perpetuating chronic inflammatory bowel disease remain unclear. Interleukin-7 (IL-7) has been previously reported to trigger the expansion of effector Th17 cells and anti-IL-7 receptor (IL-7R) antagonism to render IL23-differentiated Th17 cells susceptible to apoptosis1. We previously reported that IL-7R pathway is locally dysregulated and over-expressed in the colon mucosa of severe IBD patients and reproducibly associated with unresponsiveness to anti-TNF or anti-α4β7 integrin therapies2. We developed a humanized anti-IL7R lusvertikimab with a good PK/PD and tolerance profile in healthy volunteers3 and recently announced positive phase 2 efficacy results in ulcerative colitis after a 10 week-induction treatment period (randomized placebo-controlled CoTikiS study: NCT04882007). Methods Here, we investigated at preclinical level the additive effect of blocking IL-7R in combination with anti-IL12/23 antagonist antibody in an anti-TNF refractory adoptive T cell transfer chronic colitis mouse model as well as in-vitro on human Th17 cell differentiation in combination with anti-IL23 antibody. Results T cell-recipient mice developed a colitis characterised by the development of diarrhoea and body weight loss with post-mortem examination confirming epithelial hyperplasia and inflammatory cell infiltration into the mucosa. Anti-IL7R monotherapy at this dose was suboptimal in this model. Anti-IL-12/23 blockade in monotherapy was efficient but not enough alone to achieve complete remission at macroscopic and histological level. In contrast, administration of anti-IL-7R in combination with anti-IL12/23 mAb was associated with a strong and significant reduction in all measured colitis symptoms, macroscopic large bowel changes and all histopathological endpoints (hyperplasia, colitis severity, inflammation). When mice were treated in combination, the group was statistically different from the anti-IL12/23 monotherapy group and no statistical difference have been measured with the non-colitis group, illustrating this combination achieved complete remission including at histological mucosal healing. In vitro, we confirmed that IL-7 drives human Th17 differentiation despite IL23 blockade and that combining IL7R and IL23 blockade was efficient to prevent Th17 generation in the presence of both IL7 and IL23. Conclusion Our findings show that anti-IL-7R is well tolerated in combination with anti-IL12/23 mAb in mice and act in synergy to achieve a profound control of chronic colitis and complete histological normalization compared to monotherapy.

DOP123 Linking microbial genes to mucosal metabolites uncovers host-microbial interactions during 5-ASA therapy for ulcerative colitis

Abstract Background The severity of ulcerative colitis (UC) depends on the state of the colon mucosa, where achieving mucosal remission markedly improves patient prognosis and quality of life. The study aimed to characterize essential mucosal metabolites and microbial gene involved in UC remission, and to elucidate the mechanisms by which specific metabolites regulate intestinal homeostasis. Methods An integrated metagenomic and metabolomic analysis was conducted to elucidate the correlation between disease-associated microbes and host mucosal metabolites. Participants included non-UC controls and individuals with UC, comprising the responding group (UCR) and ineffective group (UCA) in 5-ASA treatment. The differential metabolite was further investigated using a DSS-induced colitis mouse model, followed by in vitro experiments to explore the mechanisms. Results The levels of mucosal secondary bile acids were found to have a significant negative association with intestinal inflammation during 5-ASA treatment. Integrated analysis of metagenomics and metabolomics revealed that host mucosal bile acid metabolites were negatively associated with the bile acid synthesis-related genes cbh in microbial genomes. Administration of the secondary bile acid mitigated mucosal inflammation in a colitis model by decreasing the proportion of Th17 and pathogenic Th17 cells. This secondary bile acid functions as an immunomodulatory metabolite, suppressing glycolysis in Th17-polarizing T cells to inhibit the Th17 cell response and modulating the gut microbiota. Conclusion These findings suggest that alterations in microbiome-metabolome interactions are critical for maintaining mucosal homeostasis during UC remission. The specific bile acid acts as an immunomodulatory metabolite, and may represent a potential therapeutic strategy for UC.

Differential pathological changes in colon microenvironments in acute and chronic mouse models of inflammatory bowel disease

ABSTRACT Inflammatory bowel disease is a chronic condition characterized by inflammation of the gastrointestinal tract, resulting from an abnormal immune response to normal stimuli, such as food and intestinal flora. Since the etiology of this disease remains largely unknown, murine models induced by the consumption of dextran-sodium sulfate serve as a pivotal tool for studying colon inflammation. In this study, we employed both acute and chronic colitis mouse models induced by varying durations of dextran-sodium sulfate consumption to investigate the pathological and immunologic characteristics throughout the disease course. During the acute phase, activated innate inflammation marked by M1 macrophage infiltration was prominent. In contrast, the chronic phase was characterized by tissue remodeling, with a significant increase in M2 macrophages and lymphocytes. RNA-sequencing revealed genetic changes in acute and chronic colitis, marked by the maintenance of genomic integrity in the acute phase and extracellular matrix dynamics in the chronic phase. These phase-specific alterations reflect the multifaceted physiological processes involved in the initiation and progression of inflammation in the large intestine, underscoring the necessity for distinct experimental approaches for each phase. The findings demonstrate that the factors shaping the large intestinal immune microenvironment change specifically during the acute and chronic phases of experimental inflammatory bowel disease, highlighting the importance of developing therapeutic strategies that align with the disease course.

Inflammation Targeting-Triggered Healing Hydrogel for In Situ Reconstruction of Colonic Mucosa.

Inflammatory bowel disease (IBD) is characterized by intestinal mucosal damage that exacerbates inflammation and promotes disease recurrence. Although hydrogel-based therapies have shown potential for mucosal repair, challenges remain due to inadequate targeting and low hydrogel density, leading to ongoing infiltration of harmful substances and delayed mucosal healing. In this study, an inflammation-targeting-triggered healing hydrogel (ITTH hydrogel) is developed, composed of polyvinyl alcohol-alginate microgels (PALMs) and a cyclodextrin polymer crosslinker (CPC). This hydrogel specifically targets inflamed colonic sites and crosslinks in situ to form a dense network. The results demonstrate that the ITTH hydrogel adheres effectively to inflamed colonic tissue in both IBD mouse models and human samples. The dense crosslinked network acts like the mucosal barrier, preventing the penetration of detrimental substances such as bacteria and small molecules, thereby protecting the underlying mucosal tissue. Furthermore, the ITTH hydrogel significantly improved therapeutic outcomes in mice with dextran sulfate sodium (DSS)-induced colitis. These findings suggest that the ITTH hydrogel is a promising candidate for in situ reconstruction of colonic mucosa and the treatment of IBD.

Polydatin protects against DSS-induced ulcerative colitis via Nrf2/Slc7a11/Gpx4-dependent inhibition of ferroptosis signalling activation.

Ulcerative colitis (UC), a form of inflammatory irritable bowel disease, is characterized by a recurrent and persistent nonspecific inflammatory response. Polydatin (PD), a natural stilbenoid polyphenol with potent properties, exhibits unexpected beneficial effects beyond its well-documented anti-inflammatory and antioxidant activities. In this study, we presented evidence that PD confers protection against dextran sodium sulfate (DSS)-induced ulcerative colitis. The protective effect of PD on colitis was examined in cultured caco-2 cells and DSS-induced colitis mouse model. Bulk RNA sequencing and differential gene expression analysis were used to investigate the protective mechanism of PD on DSS-induced colitis. Ferroptosis was determined by MDA levels, SOD levels, mitochondrial iron accumulation and ROS production. Ferroptosis-related proteins Slc7a11, Nrf2 and Gpx4 levels were measured by western blot, immunohistochemical and immunofluorescence staining. PD mitigated the DSS-induced increases in pro-inflammatory cytokines (IL-6, TNF-α, and IL-1β), alleviated colon length shortening, reduced morphological damage to the intestinal mucosa, and preserved tight junction proteins (TJ) occludin and Zonula occludens-1 (ZO-1) in both caco-2 cells and murine models of colitis. Mechanistically, PD reversed the reduction of Nrf2, Slc7a11 and Gpx4, the degree of nuclear translocation of Nrf2 induced by DSS in vitro and in vivo significantly. Moreover, the protective effect of PD is attenuated by erastin and resembled that of Fer-1 in caco-2 cells model. Our study suggested that PD protects against DSS-induced ulcerative colitis via Nrf2/Slc7a11/Gpx4-dependent inhibition of ferroptosis signalling activation. Further investigation into the precise mechanisms underlying this phenomenon is warranted. The findings presented herein indicated that PD may serve as a potential therapeutic agent for patients with UC.

Protective role of ABCC drug subfamily resistance transporters (ABCC1-7) in intestinal inflammation.

The ABCC subfamily contains thirteen members. Nine of these transporters are called multidrug resistance proteins (MRPs). The MRPs have been associated with developing ulcerative colitis (UC). This study aimed to evaluate the ABCC expression in UC patients and its role in a dextran sulfate sodium (DSS)-induced colitis mice model under 5-aminosalicylates or methylprednisolone treatment and compared with control without inflammation. DSS-induced colitis mice were treated with 5-aminosalicylates (50mg/kg 24h) or methylprednisolone (2mg/kg 24h). Human rectal biopsies were obtained from UC patients. The abcc-relative mRNA levels and protein expression were determined by RT-PCR and immunohistochemistry. abcc4, abcc5, and abcc6 mRNA levels were significantly increased in DSS-induced colitis compared to the other groups. The 5-aminosalicylate treatment dramatically increased the abcc2 and abcc3 mRNA levels vs. control. Methylprednisolone treatment increased abcc1 vs. DSS-induced colitis and colitis treated with 5-aminosalicylate. Immunohistochemical analysis revealed down-regulation of ABCC1/ABCC2/ABCC5/ABCC7 in mice colitis vs. control. Treatment with 5-aminosalicylate restored ABCC5 levels, while methylprednisolone restored ABCC2/ABCC5/ABCC7 in colitis mice at similar control levels. Relative mRNA levels of mrp1-5 were increased in active UC patients vs. control. ABCC2/ABCC4/ABCC7 were conspicuously expressed in the mucosa of 5-aminosalicylate and/or methylprednisolone-treated UC patients, while ABCC2/ABCC4/ABCC5/ABCC7 in submucosa, ABCC1/ABCC5/ABCC7 in muscular, and ABCC1/ABCC4/ABCC5/ABCC7 in serosa were expressed vs. controls. This is the first report about the differential up-regulation of the ABCC subfamily gene and protein expression in DSS-induced colitis under aminosalicylates or methylprednisolone treatment.

MAPK signaling mediated intestinal inflammation induced by endoplasmic reticulum stress and NOD2.

Endoplasmic reticulum (ER) stress is crucially involved in inflammatory bowel disease (IBD), but the mechanisms remain incompletely understood. This study aimed to elucidate how ER stress promotes inflammation in IBD. ER stress marker Grp78 and NOD2 in colon tissues of Crohn's disease (CD) patients and IBD model mice were detected by immunohistochemical analysis. THP-1 cells were exposed to ER stress and the expression of NOD2 and inflammatory cytokines was detected by PCR. We found that ER stress markers Grp78 and NOD2 were upregulated in intestinal tissues of CD patients and in THP-1 cells exposed to ER stress. ER stress inhibitor reduced Grp78 and NOD2 expression in colitis model mice and alleviated colitis. ER stress inducer cooperated with NOD2 ligand MDP to upregulate TNF-α, IL-8 and IL-1β, and activate MAPK signaling in THP-1 cells. Moreover, inhibitors of MAPK signaling led to the downregulation of IL-1β, IL-8 and TNF-α in THP-1 cells stimulated by ER stress inducer and MDP. In conclusion, ER stress upregulates NOD2 and promotes inflammation in IBD, at least partially due to the activation of MAPK pathway.

A Nitrate/Nitrite Biosensor Designed with an Antiterminator for In Vivo Diagnosis of Colitis Based on Bacteroides thetaiotaomicron.

Bacteroides thetaiotaomicron is a common microorganism in the human gut that has been linked to health benefits. Furthermore, it is an emerging synthetic biology chassis with the potential to be modified into diagnostic or therapeutic engineered probiotics. However, the absence of biological components limits its further applications. In this study, we developed an antiterminator microbial whole-cell biosensor (MWCB) based on B. thetaiotaomicron. The antiterminator-based element allows the chassis to detect colitis in mice by responding to nitrate and nitrite in an inflammatory environment. In particular, the nitrate/nitrite-inducible promoter was obtained by combining the constitutive promoter with the inducible terminator. Subsequently, the promoter and RBS were replaced to optimize a sensitive and specific response to nitrate/nitrite. A preliminary in vitro assessment was conducted to ascertain the functionality of the biosensor. Its in vivo sensing ability was evaluated in a chemically induced mouse model of ulcerative colitis (UC). The results demonstrated that the MWCB exhibited a robust response to colitis, with a notable positive correlation between the intensity of the response and the level of inflammation. This novel sensing element may provide a new avenue for the development of components for unconventional chassis, like B. thetaiotaomicron. It will also facilitate the development of engineered probiotics based on B. thetaiotaomicron, thereby providing patients with a wider range of medical treatment options.

The Effect of the Size of Gold Nanoparticle Contrast Agents on CT Imaging of the Gastrointestinal Tract and Inflammatory Bowel Disease.

Ulcerative colitis (UC) is a chronic inflammatory bowel disease (IBD). CT imaging with contrast agents is commonly used for visualizing the gastrointestinal (GI) tract in UC patients. Contrast agents that provide enhanced imaging performance are highly valuable in this field. Recent studies have made significant progress in developing better contrast agents for imaging the gastrointestinal tract using nanoparticles. However, the impact of nanoparticle size on this application remains unexplored. Gold nanoparticles (AuNPs) serve as an ideal model to investigate the effect of nanoparticle size on imaging of the gastrointestinal tract due to their controllable synthesis across a broad size range. In this study, we synthesized AuNPs with core sizes ranging from 5 to 75 nm to examine the effect of the size in this setting. AuNPs were coated with poly(ethylene glycol) (PEG) to enhance stability and biocompatibility. In vitro tests show that gold nanoparticles are cytocompatible with macrophage cells (∼100% cell viability) and remain stable under acidic conditions, with no significant size changes over time. Phantom imaging studies using a clinical CT scanner indicated that there was no effect of nanoparticle size on CT contrast production, as previously demonstrated. In vivo imaging using a mouse model of acute colitis revealed a strong contrast generation throughout the GI tract for all agents tested. For the most part, in vivo contrast was independent of AuNP size, although AuNP outperformed iopamidol (a clinically approved control agent). In addition, differences in attenuation trends were observed between healthy and colitis mice. We also observed almost complete clearance at 24 h of all formulations tested (less than 0.7% ID/g was retained), supporting their value as a model platform for studying nanoparticle behavior in imaging. In conclusion, this study highlights the potential of nanoparticles as effective contrast agents for CT imaging of the gastrointestinal tract (GIT) in the UC. Further systemic research is needed to explore contrast agents that can specifically image disease processes in this disease setting.

Luteolin Alleviates Ulcerative Colitis in Mice by Modulating Gut Microbiota and Plasma Metabolism.

Ulcerative colitis (UC) is a chronic and easily recurrent inflammatory bowel disease. The gut microbiota and plasma metabolites play pivotal roles in the development and progression of UC. Therefore, therapeutic strategies targeting the intestinal flora or plasma metabolites offer promising avenues for the treatment of UC. Luteolin (Lut), originating from a variety of vegetables and fruits, has attracted attention for its potent anti-inflammatory properties and potential to modulate intestinal flora. The therapeutic efficacy of Lut was evaluated in an established dextran sodium sulfate (DSS)-induced colitis mice model. The clinical symptoms were analyzed, and biological samples were collected for microscopic examination and the evaluation of the epithelial barrier function, microbiome, and metabolomics. The findings revealed that Lut administration at a dose of 25 mg/kg significantly ameliorated systemic UC symptoms in mice, effectively reduced the systemic inflammatory response, and significantly repaired colonic barrier function. Furthermore, Lut supplementation mitigated gut microbiota dysbiosis in a UC murine model, increasing the abundance of Muribaculaceae, Rikenella, and Prevotellaceae while decreasing Escherichia_Shigella and Bacteroides levels. These alterations in gut microbiota also influenced plasma metabolism, significantly increasing phosphatidylcholine (PC), 6'-Deamino- 6'-hydroxyneomycin C, and gamma-L-glutamyl-butyrosine B levels and decreasing Motapizone and Arachidoyl-Ethanolamide (AEA) levels. This study reveals that Lut supplementation modulates intestinal inflammation by restoring the gut microbiota community structure, thereby altering the synthesis of inflammation-related metabolites. Lut is a potential nutritional supplement with anti-inflammatory properties and offers a novel alternative for UC intervention and mitigation. In addition, further studies are needed to ascertain whether specific microbial communities or metabolites can mediate the recovery from UC.

Polymerization of dietary fructans differentially affects interactions among intestinal microbiota of colitis mice.

The intestinal microbiota plays a critical role in maintaining human health and can be modulated by dietary interventions and lifestyle choices. Fructans, a dietary carbohydrate, are selectively utilized by the intestinal microbiota to confer health benefits. However, the specific effects of different fructan types on microbial changes and functions remain incompletely understood. Here, we investigated how the intestinal microbiota responds to fructans with varying degrees of polymerization in the context of gut dysbiosis. Both low molecular weight fructo-oligosaccharides and high molecular weight levan suppressed intestinal inflammation in a colitis mouse model, mitigating intestinal fibrosis and dysbiosis. Although both the effects of fructo-oligosaccharides and levan are microbiota-dependent, distinct modulation patterns of the intestinal microbiota were observed based on the molecular weight of the fructans. Levan had a more pronounced and persistent impact on gut microbiota compared to fructo-oligosaccharides. Levan particularly promoted the abundance of Dubosiella newyorkensis, which exhibited preventive effects against colitis. Our findings highlight the importance of polymerization levels of dietary fructans in microbiota alterations and identify Dubosiella newyorkensis as a potential probiotic for treating inflammatory diseases.

Helminth extracellular vesicles co-opt host monocytes to drive T cell anergy.

Parasitic helminths secrete extracellular vesicles (EVs) into their host tissues to modulate immune responses, but the underlying mechanisms are poorly understood. We demonstrate that Ascaris EVs are efficiently internalised by monocytes in human peripheral blood mononuclear cells and increase the percentage of classical monocytes. Furthermore, EV treatment of monocytes induced a novel anti-inflammatory phenotype characterised by CD14+, CD16-, CC chemokine receptor 2 (CCR2-) and programmed death-ligand 1 (PD-L1)+ cells. In addition, Ascaris EVs induced T cell anergy in a monocyte-dependent mechanism. Targeting professional phagocytes to induce both direct and indirect pathways of immune modulation presents a highly novel and efficient mechanism of EV-mediated host-parasite communication. Intra-peritoneal administration of EVs induced protection against gut inflammation in the dextran sodium sulphate model of colitis in mice. Ascaris EVs were shown to affect circulating immune cells and protect against gut inflammation; this highlights their potential as a subject for further investigation in inflammatory conditions driven by dysregulated immune responses. However, their clinical translation would require further studies and careful consideration of ethical implications.

Protective effects and mechanisms of extracts of Gleditsia sinensis Lam. Thorn on DSS-induced colitis in mice.

Inflammatory Bowel Disease (IBD), encompassing Ulcerative Colitis (UC) and Crohn's Disease (CD), stems from a multifaceted interaction of hereditary, immunological, ecological, and microbial elements. Current treatments have limitations, necessitating new therapeutic approaches. This study investigates the safeguarding impacts and fundamental processes of extracts of Gleditsia sinensis Lam. thorn (EGST) in a dextran sulfate sodium (DSS)-induced colitis model in mice. A total of 180g of dried EGST were prepared, and untargeted metabolomic profiling using high-resolution liquid chromatography electrospray ionization orbitrap mass spectrometry (HR-LC-ESI-Orbitrap-MS) identified 930 compounds. UC model mice were administered 3% DSS for 7d, followed by EGST treatment. The analysis encompassed physiological and pathological evaluations, serum cytokine ELISA, gut microbiota (GM) metagenomic sequencing, GC-MS metabolomics, mRNA sequencing, and Western Blot. EGST markedly mitigated colitis symptoms, evidenced by reduced weight loss, lower DAI scores, and less colon shortening. It also decreased levels of pro-inflammatory cytokines (TNF-α, IL-6, IL-1β) while boosting IL-10. Histological examination revealed diminished tissue damage, restoration of crypts, and reduced inflammation, with barrier integrity maintained via upregulation of occludin and ZO-1. Metagenomic sequencing demonstrated that EGST modulated the GM, enhancing the levels of Firmicutes and Bacteroidetes while reducing the levels of Proteobacteria and Verrucomicrobia. Metabolomic analysis indicated that EGST influenced critical pathways, including those involving D-amino acids, glutathione, cysteine, and methionine metabolism. Furthermore, mRNA sequencing identified 2625 differentially expressed genes (DEGs), comprising 1729 with increased and 896 with decreased expression, and highlighted EGST's impact on the PPARγ/AMPK/NF-κB pathway. Overall, EGST mitigates DSS-induced colitis through modulation of GM, metabolic profiles, and gene expression, suggesting its promise as a naturally derived treatment for colitis.

Diverse domains of raspberry pectin: critical determinants for protecting against IBDs.

Inflammatory bowel diseases (IBDs), including Crohn's disease (CD) and ulcerative colitis (UC), are chronic conditions characterized by periods of intestinal inflammation and have become global diseases. Dietary pectins have shown protective effects on IBD models. However, the development of pectin-based diet intervention for IBD individuals requires knowledge of both the bioactive structural patterns and the mechanisms underlying diet-microbiota-host interactions. Here, dextran sulfate sodium (DSS) induced colitis mice were fed with different pectins with various domain compositions, including AG, P37, P55 and P85, in order to understand why different structural patterns function differently on colitis mouse models. The structural diversity of pectin manifests in the different percentages of the homogalacturonan (HG) backbone, Ara sidechains, and Gal sidechains. AG comprises only neutral sugar chains consisting of 14% Ara and 86% Gal, and P85 is a commercial HG pectin mainly composed of 85% HG. P37 and P55 were isolated from raspberry pulps with different domain ratios (P37 = 37% HG + 22% Ara + 32% Gal; P55 = 55% HG + 16% Ara + 18% Gal). Compared to the monotonous structure of AG and P85, the domain-diverse pectins P37 and P55 show superior protective effects against colitis through inhibiting the proliferation of the mucin-consuming bacteria and the pro-inflammatory microorganisms, potentiating the MUC2 expression and the mucus layer and regulating the gut-spleen axis. The HG structure promoted the proliferation of the mucin-degrading microbiota and potentiated mucus erosion. AG enhanced the mucus thickness but increased the growth of the pro-inflammatory microbiota. Our study revealed that the specific domain composition of pectic fibers was a key factor on which the diet-induced alterations in the gut microbiota and the intestinal barrier function highly depended.