Mouse Model Of Colitis Research Articles

Spleen tyrosine kinase aggravates intestinal inflammation through regulating inflammatory responses of macrophage in ulcerative colitis.

Ulcerative colitis (UC) is a persistent chronic, non-specific inflammatory disease, and macrophages play a crucial role in its pathogenesis. Spleen tyrosine kinase (Syk) is strongly associated with the pathogenesis of several inflammatory diseases. However, the role of Syk in the pathogenesis of UC is still obscure. Syk expression was analyzed in peripheral blood mononuclear cells (PBMCs) and colonic tissues of UC patients using quantitative reverse transcription-polymerase chain reaction (qRT-PCR) and immunofluorescence. A public database was used to analyze the expression of selected signature genes of interest in UC patients with different expressions of Syk. R788, a small molecule inhibitor of Syk, was used to treat macrophages from mice. The functions of macrophages were assessed using qRT-PCR, flow cytometry, and fluorescence microscopy. Dextran sodium sulfate (DSS)-induced colitis mice model was established to determine the role of Syk in UC. The Syk levels were markedly increased in PBMCs, colonic tissues, and colonic mucosa lamina propria macrophages from UC patients, and positively related to disease activity. Inhibition of Syk with R788 decreased pro-inflammatory genes expression and increased anti-inflammatory genes expression in peritoneal macrophages and bone marrow macrophages. Blockade of Syk enhanced phagocytosis and bactericidal ability of macrophages. Syk promoted the production of reactive oxygen species of macrophages and M1-type macrophage polarization. Furthermore, inhibition of Syk alleviated intestinal mucosal inflammation in DSS-induced colitis model. Syk plays a vital role in intestinal inflammation by regulating inflammatory responses of macrophages in UC. Targeting Syk may be a promising therapeutic approach for UC.

Adhesive polyelectrolyte coating through UV-triggered polymerization on PLGA particles for enhanced drug delivery to inflammatory intestinal mucosa

Administering medication precisely to the inflamed intestinal sites to treat ulcerative colitis (UC), with minimized side effects, is of urgent need. In UC, the inflammation damaged mucosa contains a large number of amino groups which are positively charged, providing new opportunities for drug delivery system design. Here, we report an oral drug delivery system utilizing the tacrolimus-loaded poly (lactic-co-glycolic acid) (TAC/PLGA) particles with an adhesion coating by in situ UV-triggered polymerization of polyacrylic acid and N-hydroxysuccinimide (PAA-NHS). The negatively charged carboxyl groups effectively interact with the positively charged focal mucosa, and the NHS ester groups form the covalent bonds with the amino groups, thereby synergically enhancing the adhesion of the PLGA particles to the focal mucosa. Our findings reveal that, compared to the naked particles, the PAA-NHS coating increases the adhesion of particles to the inflammatory intestine. In a dextran sulfate sodium-induced acute colitis mouse model, the TAC/PLGA particles with PAA-NHS coating exhibits substantial retention of TAC within the inflammatory intestine, enhancing drug delivery efficiency and therapeutic effects. This approach holds promise for UC management, minimizing systemic side effects and optimizing therapeutic outcomes.Graphical abstract

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

IntroductionUlcerative 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.MethodsThe 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.ResultsPD 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.DiscussionOur 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.

Chemical Composition of Cynanchum auriculatum Royle Ex Wight and Its Potential Role in Ameliorating Colitis.

Cynanchum auriculatum Royle ex Wight, commonly known as "Baishouwu," has been traditionally used in China for its medicinal and dietary benefits. Despite its long history of use, the potential therapeutic effects of C. auriculatum in the treatment of colitis have not been fully investigated. This study aims to evaluate the effects of the water extract of C. auriculatum root on colitis and elucidate its potential mechanisms of action. The water extract of C. auriculatum root (CW) was prepared and characterized using UPLC-Q-TOF-MS, identifying thirty-two distinct compounds, including saponins, organic acids, fatty acid derivatives, and alkaloids. The therapeutic efficacy of CW was assessed in a colitis mouse model. CW significantly alleviated colitis symptoms, evidenced by increased colon length, reduced disease activity indices, and decreased colon tissue damage. CW reduced colonic inflammatory cytokine production and enhanced the expression of tight junction proteins, including claudin-1, occludin, and ZO-1, thereby strengthening intestinal barrier integrity. Additionally, CW modulated the gut microbiota by increasing microbial diversity, promoting beneficial Lactobacillus growth, reducing pathogenic Pseudomonas levels, and enhancing short-chain fatty acid production. The results suggest that CW exhibits significant therapeutic potential in the management of colitis by attenuating inflammation, restoring gut barrier function, and modulating the gut microbiota. These findings provide a basis for further exploration of C. auriculatum as a functional food for prevention and treatment of colitis.

Kuiyangling Enema Alleviates Ulcerative Colitis Mice by Reducing Levels of Intestinal NETs and Promoting HuR/VDR Signaling.

Kuiyangling is a traditional Chinese medicine formula usedfor the treatment of ulcerative colitis, but the specific mechanism remains unclear. Imbalance in NETs regulation is one of the important factors contributing to the onset of ulcerative colitis (UC). The HuR/VDR signaling pathway plays a significant role in restoring the intestinal mucosal barrier in UC. The aim of this study is to explore the mechanism of Kuiyangling in the treatment of ulcerative colitis. A mouse model of ulcerative colitis using 3% DSS water was considered, and model, normal, Kuiyangling medium- (5 g·kg-1) and high-dose (10 g·kg-1), and mesalazine (50 mg·kg-1) groups were created. Measurements of colon length, spleen index, histopathological variances, subcellular structure observations, ROS content, and NET-related proteins (PAD4, MPO, citH3) were obtained through HE staining, electron microscopy, live imaging, and Western blotting assays. Immunohistochemistry and immunofluorescence analyses were conducted to assess the levels of HuR/VDR protein complex, ZO-1, Occludin, Claudin-7, and intestinal NETs. An ELISA kit was utilized to determine cytokine levels, LC-MS was performed to analyze the composition of Kuiyangling, and next-generation sequencing was conducted for detection of the intestinal mucosal transcriptome. Kuiyangling reduced DAI, splenic index, and ROS content; maintained mucosal structure; decreased inflammation; and increased colon length and body mass index. Western blotting indicated that Kuiyangling reduced PAD4,MPO, and citH3 levels. Kuiyangling decreased NETs and increased the expression levels of ZO-1, Occludin, and Claudin-7, as well as up-regulating HuR, VDR, and HuR/VDR proteins. Kuiyangling reduced IL-1β, IL-6, and TNF-α levels while increasing TGF-β, IL-10, and IL-37 levels. Kuiyangling reduced inflammatory response proteins and elevated the levels of anti-inflammatory and intestinal barrier proteins, possibly inhibiting the TNF and oxidative phosphorylation signaling pathways. Kuiyangling enema in treating ulcerative colitis in mice, associated with a reduction in intestinal NETs and enhancement of HuR-mediated intestinal barrier signaling pathways.

Rosavin derived from Rhodiola alleviates colitis in mice through modulation of Th17 differentiation

BackgroundRosavin (RSV) is a naturally occurring compound isolated from Rhodiola species. Although RSV has been reported with pharmacological activities of anti-oxidation, anti-inflammation, anti-stress and immunomodulation, its effect on colitis relieving and the underlying mechanism remains unclear. PurposeThis study aims to investigate whether and how RSV alleviated colitis in mice. Study Design and MethodsThe protective effect of RSV (50, 100, 200 mg/kg, p.o.) was investigated on dextran sulfate sodium (DSS) mediated mouse models of acute and chronic colitis. Alterations in fecal microbiota was evaluated by 16S rRNA sequencing. Pseudo germ-free mice by antibiotics treatment was applied to evaluate the RSV-mediated functional role of gut microbiota on colitis. RNA sequencing was performed to determine RSV-induced colonic response. Primary T cell culture was conducted to see the effect of RSV on Th17 and Treg differentiation. Whole blood assay, dual luciferase reporter assay and molecular docking method were applied to investigate the mechanism and target of RSV in Th17 regulation. ResultsOral RSV significantly relieved DSS-mediated acute and chronic colitis in mice, which recovered body weight loss, reduced disease activity index, alleviated colon injury, inhibited inflammation, suppressed the apoptosis of intestinal epithelia and maintained intestinal barrier function. Moreover, RSV specifically regulated intestinal microbiota by recovering DSS-mediated microbial changes and elevating beneficial microbes of Lactobacillus and Akkermansia. Antibiotics treatment experiment showed that the protective role of RSV was at least partially dependent on gut microbiota; however, in vitro incubation showed that RSV did not directly promote the growth of Lactobacillus and Akkermansia strains. Further analysis showed that RSV-mediated genetic alteration in colon was enriched in lymphocyte regulation. Moreover, RSV regulated the balance of Th17/Treg in colitis mice. Importantly, RSV inhibited the differentiation of Th17 cell in vitro, suppressed the generation of IL-17 by Th17 cells, and downregulated Rorc encoding RORγt and the downstream Il17. RSV significantly inhibited the RORγt transcription activity, and bound to the RORγt ligand binding domain. ConclusionRSV alleviates murine colitis through regulating intestinal immunity. Notably, RSV is identified as a novel Th17 regulator that inhibits RORγt-mediated Th17 differentiation. The results potentiate the Rhodiola-derived chemical as novel anti-colitis agents.

Cannabidiol Alleviates Intestinal Fibrosis in Mice with Ulcerative Colitis by Regulating Transforming Growth Factor Signaling Pathway.

The aim of this study is to investigate the protective effect of Cannabidiol (CBD) on DSS-induced colitis in C57BL/6 mice and its related pathways. A mouse model of ulcerative colitis (US) was induced by DSS. Enzyme-linked immunosorbent assay (ELISA), quantitative reverse transcription polymerase-chain reaction (qRT-PCR), Western blot (WB) and immunofluorescence (IF) were used to identify the key factors involved in inflammatory response, oxidative stress and intestinal fibrosis. In addition, we transfected si-RNA into CCD-18Co cells. The research suggests that CBD significantly improves intestinal inflammation by up-regulating the nuclear factor erythroid 2-related factor 2 (Nrf2) expression, inhibiting the classical Nuclear Factor kappa-light-chain-enhancer of activated B cells (NF-κb) pathway, and inhibiting the release of IL-6 (Interleukin), IL-1β, Tumor Necrosis Factor-α (TNF-α) and other factors. At the same time, CBD plays an antioxidant role by regulating Nrf2/ HO-1 (Heme Oxygenase-1) pathway and activating HO-1 activity. On the other hand, CBD may regulate Transforming growth factor beta (TGF-β)/SMADs signaling pathway by inhibiting the expression of TGF-β1, thereby inhibiting the expression of α-SMA, Collagen1, TIMP1 and other factors, thus playing an anti-fibrotic role. Notably, when Nrf2 is inhibited or lacking, CBD loses the above protective effect against DSS-induced colon injury. CBD affects the classical NF-κb pathway, Nrf2/ Heme Oxygenase-1 (HO-1) pathway, and Transforming growth factor beta (TGF-β)/SMAD pathway by regulating Nrf2, thereby reducing colonic inflammation and oxidative stress and improving the progression of colonic fibrosis.

Longitudinal single-cell RNA sequencing reveals a heterogeneous response of plasma cells to colonic inflammation.

A comprehensive understanding of the dynamic changes in plasma cells (PCs) during inflammation remains elusive. In this study, we analyzed the distinct responses of PCs across different phases of inflammation in a dextran sodium sulfate (DSS)-induced mouse colitis model. Six-week-old male C57BL/6 mice were treated with 2.2% DSS in distilled water for 5days to induce colitis, and colonic tissues were collected at the peak of inflammation, during recovery, and at the end of the recovery phase. Single-cell RNA sequencing was performed to investigate temporal changes in the gut immune environment. PCs were categorized into six subsets, with Ube2c+PCs displaying notable alterations during various inflammatory phases. Genes such as Pycard, Gpx1, Lgals3, and Chchd10 were significantly expressed in Ube2c+PCs and appeared critical in resolving DSS-induced inflammation. Transcription factors (TFs), including Atf4, Cebpg, Jund, and Klf6, exhibited high regulatory activity in Ube2c+PCs across inflammatory stages. Additionally, we identified an interaction between Chchd10 and C1qbp in PCs, which stabilized C1qbp, reduced reactive oxygen species (ROS) production, and potentially enhanced PC survival and function under inflammatory conditions. This study highlights dynamic quasi-temporal gene expression and TF regulation in PCs during colitis, providing insights for future PC-targeted immunotherapy research.

Heat-killed Lacticaseibacillus paracasei 6235 is more effective than live on DSS-induced colitis via modulation of intestinal microbiota and MAPK/NF-κB signaling pathways.

This study compared the protective effects of both live Lacticaseibacillus paracasei 6235 (LLP 6235) and heat-killed Lacticaseibacillus paracasei 6235 (HK-LP 6235) on ulcerative colitis. Using a dextran sulfate sodium (DSS)-induced colitis mouse model, we evaluated physiological state, colon tissue integrity, inflammatory factors, tight junction (TJ) proteins, and intestinal microbiota variations. The findings demonstrated that both LLP 6235 and HK-LP 6235 have the capacity to mitigate colitis damage, enhance TJ protein levels, and restore colon morphology. In addition, these interventions modulated the intestinal inflammatory response by inhibiting pro-inflammatory factors and upregulating anti-inflammatory factors through the mitogen-activated protein kinase (MAPK) and nuclear factor kappa B (NF-κB) signaling pathways. Moreover, treatment with LLP 6235 and HK-LP 6235 significantly altered intestinal microbiota diversity, increased the relative abundance of beneficial bacteria, and regulated the short-chain fatty acid (SCFA) levels. Spearman correlation analysis revealed a strong association between TJ proteins, SCFAs, intestinal microbiota, and inflammatory response, suggesting that LLP 6235 and HK-LP 6235 may provide an effective approach to colitis prevention. In conclusion, LLP 6235 and HK-LP 6235 have similar abilities; furthermore, HK-LP 6235 modulated the intestinal microbiota through lipid metabolic pathways, resulting in a greater improvement. Moreover, considering the high stability and safety of prebiotics and their wide applicability, HK-LP 6235 is recommended for use as a modulator of intestinal inflammatory diseases.