Murine Model Of Experimental Colitis Research Articles

Bacillus subtilis SF106 and Bacillus clausii SF174 spores reduce the inflammation and modulate the gut microbiota in a colitis model.

Chronic intestinal inflammation is associated with strong alterations of the microbial composition of the gut. Probiotic treatments and microbiota-targeting approaches have been considered to reduce the inflammation, improve both gut barrier function as well as overall gastrointestinal health. Here, a murine model of experimental colitis was used to assess the beneficial health effects of Bacillus subtilis SF106 and Bacillus clausii (recently renamed Shouchella clausii) SF174, two spore-forming strains previously characterised in vitro as potential probiotics. Experimental colitis was induced in BALB/c mice by the oral administration of dextran sodium sulphate (DSS) and groups of animals treated with spores of either strain. Spores of both strains reduced the DSS-induced inflammation with spores of B. clausii SF174 more effective than B. subtilis SF106. Spores of both strains remodelled the mouse gut microbiota favouring the presence of beneficial microbes such as members of the Bacteroidetes and Akkermansia genera.

Banana Lectin: A Novel Immunomodulatory Strategy for Mitigating Inflammatory Bowel Disease.

Compared to the general population, patients with inflammatory bowel disease (IBD) are less likely to be vaccinated, putting them at an increased risk of vaccine-preventable illnesses. This risk is further compounded by the immunosuppressive therapies commonly used in IBD management. Therefore, developing new treatments for IBD that maintain immune function is crucial, as successful management can lead to better vaccination outcomes and overall health for these patients. Here, we investigate the potential of recombinant banana lectin (rBanLec) as a supporting therapeutic measure to improve IBD control and possibly increase vaccination rates among IBD patients. By examining the therapeutic efficacy of rBanLec in a murine model of experimental colitis, we aim to lay the foundation for its application in improving vaccination outcomes. After inducing experimental colitis in C57BL/6 and BALB/c mice with 2,4,6-trinitrobenzene sulfonic acid, we treated animals orally with varying doses of rBanLec 0.1-10 µg/mL (0.01-1 µg/dose) during the course of the disease. We assessed the severity of colitis and rBanLec's modulation of the immune response compared to control groups. rBanLec administration resulted in an inverse dose-response reduction in colitis severity (less pronounced weight loss, less shortening of the colon) and an improved recovery profile, highlighting its therapeutic potential. Notably, rBanLec-treated mice exhibited significant modulation of the immune response, favoring anti-inflammatory pathways (primarily reduction in a local [TNFα]/[IL-10]) crucial for effective vaccination. Our findings suggest that rBanLec could mitigate the adverse effects of immunosuppressive therapy on vaccine responsiveness in IBD patients. By improving the underlying immune response, rBanLec may increase the efficacy of vaccinations, offering a dual benefit of disease management and prevention of vaccine-preventable illnesses. Further studies are required to translate these findings into clinical practice.

Ameliorative Effect of Aqueous and Hydroalcoholic Extracts of Scrophularia striata Boiss. on Murine Model of Experimental Colitis.

Scrophularia striata Boiss. (S. striata) is a flowering plant with several therapeutic properties including antiinflammatory, antioxidant, antimicrobial, and wound-healing activity. Regarding the side effects of drugs conventionally used for inflammatory bowel disease (IBD) treatment, we investigated the anticolitis properties of aqueous (SSAE) and hydroalcoholic (SSHE) extracts of S. striata on experimental colitis. The colitis was induced using acetic acid (3%) and 2 h before ulcer induction, each group of rats received orally three doses (150, 300, and 600 mg/kg, p.o.) of SSAE or SSHE for the next 5 days. Dexamethasone (1 mg/kg, i.p.) and mesalazine (100 mg/kg, p.o.) were used as reference drugs. Different parameters including weight of colon/height, ulcer index, total colitis index, levels of myeloperoxidase (MPO) and malondialdehyde (MDA) were investigated. Total phenolic contents were 4.3 ± 0.2 and 7.1 ± 0.4 mg/g equivalent to gallic acid for SSAE and SSHE respectively. Three applied doses of SSHE and the highest dose of SSAE (600 mg/kg) could reduce all the macroscopic and pathologic indices of colitis and the levels of MPO and MDA. Two lesser doses of SSAE (150, 300 mg/kg) however, couldn't diminish the histopathologic features of colitis and the values of MPO and MDA. S. striata, especially SSHE, which also contained more phenolic compounds, had an ameliorating effect on ulcerative colitis and possibly exerts this effect through its antioxidant, antiinflammatory and wound healing properties. Further investigations are required to introduce this plant as a novel alternative herbal drug for colitis treatment.

The Wu-Shi-Cha formula protects against ulcerative colitis by orchestrating immunity and microbiota homeostasis

Ethnopharmacological relevanceUlcerative colitis (UC) has become a healthy burden worldwide due to its insidious onset and repetitive relapse, with a rather complex etiology, including inappropriate immune response, dysbiosis, genetic susceptibility, and unhealthy diets. The Wu-Shi-Cha (WSC) formula is a widely utilized drug to protect against gastrointestinal disorders. Aim of the studyThe study aspired to dissect the pertinent mechanisms of the WSC to treat UC. Materials and methodsNetwork pharmacology and weighted gene co-expression network analysis (WGCNA) were performed to predict the targets of WSC in the context of UC and colorectal cancer. Dextran sodium sulfate (DSS) was used to construct murine models of experimental colitis, and the WSC was given to colitis mice for 14 days. Feces and colon samples were subjected to 16S rRNA gene sequencing combined with liquid chromatography-mass spectrometry (LC-MS) and biochemical experiments, respectively. ResultsNetwork pharmacology analysis predicted that the WSC formula could orchestrate inflammation, infection, and tumorigenesis, and WGCNA based on The Cancer Genome Atlas (TCGA) database showed a potent anti-neoplastic effect of the WSC therapy for colorectal cancer. The WSC therapy rescued bursts of pro-inflammatory cytokines and colonic epithelial collapse in DSS-induced colitis mice. Moreover, the high dose of WSC treatment facilitated the alternative activation of peritoneal macrophages (Mφs) and these Mφs were conducive to the survival of intestinal stem cells (ISCs), and the disturbed homeostasis of gut microbiota was re-established after WSC treatment, as evidenced by the decreased colonization of pathological taxa in the fecal samples. ConclusionThe WSC formula suppresses inflammation and re-establishes the homeostasis of gut microbiota, thereby ameliorating colitis progression.

Role of cyclooxygenase pathways in bowel fibrotic remodelling in a murine model of experimental colitis.

Gut fibrosis occurs under chronic inflammation. This study examined the effects of different cyclooxygenase (COX) inhibitors on fibrosis in the inflamed colon. Colitis was induced by 2,4-dinitrobenzenesulfonic acid (DNBS) in albino male Sprague-Dawley rats. After 6, 12 and 18 days, macroscopic and microscopic damage, collagen and elastic fibre content were examined. At day 6, pro-fibrotic factors (collagen I and III, hydroxyproline, fibronectin, matrix metalloproteinase-2 and -9), transforming growth factor-beta (TGF-β) signalling [TGF-β, Ras homolog gene family member A (RhoA), phosphorylated small mother against decapentaplegic (pSMAD)-2 and -6] and peristalsis were assessed, and the effects of indomethacin, SC-560 or celecoxib were tested. Six days after DNBS administration, significant histopathological signs of fibrotic remodelling were observed in rats. At day 6, pro-fibrotic factors were up-regulated and colonic peristalsis was altered. COX inhibitors reversed the histochemical, molecular and functional changes in the fibrotic colon. COX inhibition reduced TGF-β expression, SMAD2 phosphorylation and RhoA, and increased SMAD6 expression. Colonic fibrosis is associated with altered bowel motility and induction of profibrotic factors driven by TGF-β signalling. COX-1 and COX-2 inhibition counteracts this fibrotic remodelling by the modulation of TGF-β/SMAD signalling, mainly via SMAD6 induction and reduction in SMAD2 phosphorylation.

Fructus ligustri lucidi suppresses inflammation and restores the microbiome profile in murine colitis models

BackgroundUlcerative colitis (UC) is pathologically characterized by an inappropriate immune response to the gut commensal microbes accompanied by persistent epithelial barrier dysfunction, and its progression increases the susceptibility to colitis-associated cancer (CAC), as well as other complications. Fructus ligustri lucidi (FLL) has a long historical application in traditional Chinese medicine due to its various pharmacological effects, including antioxidation and anti-inflammation. The present study aimed to explore the molecular and cellular mechanisms of FLL in treating colitis. MethodsA high-performance liquid chromatography (HPLC) combined with ultraviolet (UV) was performed to validate the quality of FLL; Network pharmacology analysis and weighted gene co-expression network analysis (WGCNA) based on The Cancer Genome Atlas (TCGA) database predicted the therapeutic value of FLL against UC and CAC; 2% dextran sodium sulfate (DSS) was administered to mice to establish murine models of experimental colitis, and FLL was given for the next 14 days at different concentrations; 16S rRNA sequencing and untargeted metabolomics were performed on fecal samples to delineate the alteration in microbiome profile; Western blotting, flow cytometry, and immunocytochemistry experiments were conducted to confirm the predicted cellular mechanisms. ResultsNetwork pharmacology analysis and WGCNA predicted that the targets of the FLL were associated with the progression of UC and the survival of patients with colorectal cancer by regulating tumor necrosis factor (TNF) and IL-17 signaling pathways, immune cell functions, responses to bacterial and reactive oxygen species (ROS), and cell proliferation. In vivo experiments corroborated that the high dose of FLL significantly attenuated the progression of experimental colitis by reversing the weight loss and bloody stool, reconstructing the integrity of colorectal epithelium, and suppressing the concentration of pro-inflammatory cytokines. Moreover, FLL treatment reduced the transition of macrophages (Mφs) to the proinflammatory phenotype and promoted Mφs-regulated wound healing, and suppressed the production of ROS in intestinal organoids (IOs) and crypts. 16S rRNA and untargeted metabolomics showed that the administration of FLL inhibited DSS-caused colonization of the potentially pathogenic gut microorganisms and reversed DSS-influenced metabolic profile. ConclusionFLL is a potent anti-colitis drug by suppressing inflammation and rescuing dysbiosis.

Validation of the Anticolitis Efficacy of the Jian-Wei-Yu-Yang Formula.

Background Inflammatory bowel disease (IBD) is a major cause of morbidity and mortality due to its repetitive remission and relapse. The Jian-Wei-Yu-Yang (JW) formula has a historical application in the clinic to combat gastrointestinal disorders. The investigation aimed to explore the molecular and cellular mechanisms of JW. Methods 2% dextran sodium sulfate (DSS) was diluted in drinking water and given to mice for 5 days to establish murine models of experimental colitis, and different doses of JW solution were administered for 14 days. Network pharmacology analysis and weighted gene co-expression network analysis (WGCNA) were utilized to predict the therapeutic role of JW against experimental colitis and colitis-associated colorectal cancer (CAC). 16S rRNA sequencing and untargeted metabolomics were conducted using murine feces. Western blotting, immunocytochemistry, and wound healing experiments were performed to confirm the molecular mechanisms. Results (1) Liquid chromatography with mass spectrometry was utilized to confirm the validity of the JW formula. The high dose of JW treatment markedly attenuated DSS-induced experimental colitis progression, and the targets were enriched in inflammation, infection, and tumorigenesis. (2) The JW targets were related to the survival probability in patients with colorectal cancer, underlying a potential therapeutic value in CRC intervention. (3) Moreover, the JW therapy successfully rescued the decreased richness and diversity of microbiota, suppressed the potentially pathogenic phenotype of the gut microorganisms, and increased cytochrome P450 activity in murine colitis models. (4) Our in vitro experiments confirmed that the JW treatment suppressed caspase3-dependent pyroptosis, hypoxia-inducible factor 1α (HIF1α), and interleukin-1b (IL-1b) in the colon; facilitated the alternative activation of macrophages (Mφs); and inhibited tumor necrosis factor-α (TNFα)-induced reactive oxygen species (ROS) level in intestinal organoids (IOs). Conclusion The JW capsule attenuated the progression of murine colitis by a prompt resolution of inflammation and bloody stool and by re-establishing a microbiome profile that favors re-epithelization and prevents carcinogenesis.

The pharmacological validation of the Xiao-Jian-Zhong formula against ulcerative colitis by network pharmacology integrated with metabolomics

Ethnopharmacological relevanceInflammatory bowel disease (IBD) is pathologically characterized by an immune response accommodative insufficiency and dysbiosis accompanied by persistent epithelial barrier dysfunction, and is divided into ulcerative colitis (UC) and Crohn's disease (CD). Its progression increases the susceptibility to colitis-associated cancer (CAC), as well as other complications. The Xiao-Jian-Zhong (XJZ) formula has a historical application in the clinic to combat gastrointestinal disorders. Aim of the studyThe investigation aimed to explore the molecular and cellular mechanisms of XJZ. Materials and methodsDextran sodium sulfate (DSS) was diluted in drinking water and given to mice for a week to establish murine models of experimental colitis, and the XJZ solution was administered for two weeks. Network pharmacology analysis and weighted gene co-expression network analysis (WGCNA) were utilized to predict the therapeutic role of XJZ against UC and CAC. 16S rRNA sequencing and untargeted metabolomics were conducted utilizing murine feces to examine the changes in the microbiome profile. Biochemical experiments were conducted to confirm the predicted functions. ResultsXJZ treatment markedly attenuated DSS-induced experimental colitis progression, and the targets were enriched in inflammation, infection, and tumorigenesis, predicted by network pharmacology analysis. Based on The Cancer Genome Atlas (TCGA) database, the XJZ-targets were related to the survival probability in patients with colorectal cancer, underlying a potential therapeutic value in cancer intervention. Moreover, the XJZ therapy successfully rescued the decreased richness and diversity of microbiota, suppressed the potentially pathogenic phenotype of the gut microorganisms, and reversed the declined linoleic acid metabolism and increased cytochrome P450 activity in murine colitis models. Our in-vitro experiments confirmed that the XJZ treatment suppressed Caspase1-dependent pyroptosis and increased peroxisome proliferators-activated receptor-γ(PPAR-γ) expression in the colon, facilitated the alternative activation of macrophages (Mφs), inhibited tumor necrosis factor-α (TNFα)-induced reactive oxygen species (ROS) level in intestinal organoids (IOs), thereby favoring the mucosal healing. ConclusionThe XJZ formula is efficacious for colitis by a prompt resolution of inflammation and dysbiosis, and by re-establishing a microbiome profile that favors re-epithelization, and prevents carcinogenesis.

Pharmacological mechanism of Shenlingbaizhu formula against experimental colitis

BackgroundUlcerative colitis (UC) is a type of inflammatory bowel disease (IBD) characterized by an overactive immune response and destruction of the colorectal epithelium with intricate pathological factors. Shenlingbaizhu (SLBZ) formula, included in the Chinese Pharmacopoeia 2020, has been widely utilized to treat UC. PurposeThe present study was designed to uncover the underlying molecular mechanisms of SLBZ formula against UC. MethodsA murine model of experimental colitis was established by orally feeding 2% dextran sodium sulfate (DSS) to mice for 7 days, followed by SLBA treatment for the next 15 days. Network pharmacology analysis was performed to predict the pharmacological mechanisms. High-throughput 16S rRNA sequencing integrated with liquid chromatography-mass spectrometry (LC-MS) was conducted on mouse stool in order to determine alterations in the composition of the intestinal microbiota and metabolites. Western blotting, immunofluorescence, and flow cytometry were performed to examine the anti-inflammatory role of SLBZ. ResultsDSS treatment induced experimental colitis, and this induction was alleviated by SLBZ treatment, as evidenced by rescued pathological symptoms in the experimental colitis mouse groups. Network pharmacology analysis showed that SLBZ-target genes were enriched in pathogen-induced infectious and inflammatory pathways, as well as neoplastic processes. SLBZ administration also modulated the gut microbiota composition and metabolic profiles of experimental colitis mice and alleviated the progression of experimental colitis. We further showed via in-vitro experiments that SLBZ suppressed macrophage (Mφ) transition to pro-inflammatory phenotype (M1), rescued tumor necrosis factor-α (TNFα)-induced pyroptosis of intestinal organoids (IOs), and decreased the recruitment of Mφs by epithelial cells. ConclusionSLBZ formula is an effective treatment for murine colitis and showed a stronger therapeutic capacity than melasazine. The pharmacological mechanisms of SLBZ involve the re-establishment of an anti-inflammatory milieu and healthy microbiome, which favors mucosal healing.

The Pharmacological Mechanism of Guchangzhixie Capsule Against Experimental Colitis.

Ulcerative colitis (UC) is the major type of inflammatory bowel disease (IBD) characterized by an overactive immune response and destruction of colorectal epithelium with intricate pathological factors. Guchangzhixie (GCZX) capsule, included in the Chinese Pharmacopoeia 2020, has been widely utilized against UC. However, the underlying molecular mechanisms have not been elucidated. In the present study, a murine model of experimental colitis was established by orally feeding 4% dextran sodium sulfate (DSS) for 5 days and subsequently subjecting to GCZX treatment for another 15 days. Network pharmacology analysis was performed to predict the pertinent mechanisms of GCZX capsule. Cellular experiments examining the functional changes of intestinal organoids (IOs), macrophages (Mφs), and human colon epithelial cell cells (NCM460 cell line) after GCZX therapy were performed. Sequencing of 16S rRNA was conducted on the stools from the mouse model. Liquid chromatography-mass spectrometry (LC–MS) was utilized to detect serum metabolites. As a result, DSS induced experimental colitis, and this induction was alleviated by GCZX treatment, as evidenced by rescued pathological symptoms in UC mouse models, such as rectal bleeding stopping, decreased levels of albumin, interleukin-17, as well as chemokine (C-X-C motif) ligand 1 (CXCL1), and reduction in colon length. Network pharmacology analysis showed that GCZX-target genes were enriched in pathogen-induced infections, inflammatory pathways, as well as neoplastic processes. DSS treatment decreased microbial diversity and led to the accumulation of pathological bacterial, which was reversed by GCZX capsule. PICRUSt2 (Phylogenetic Investigation of Communities by Reconstruction of Unobserved States) based on profiles of microbiota composition demonstrated a decreased incidence of infectious disease and cancers after GCZX therapy. In full accordance with these data, GCZX administration suppressed Mφ transition to pro-inflammatory phenotype, alleviated tumor necrosis factor-α (TNFα)-compromised IOs functions, and decreased the recruitment of Mφs by epithelial cells. We conclude that GCZX capsule is an effective drug for UC and its pharmacological mechanisms involve re-establishing an anti-inflammatory milieu and favoring mucosal healing.

Astragalus polysaccharide prevents ferroptosis in a murine model of experimental colitis and human Caco-2 cells via inhibiting NRF2/HO-1 pathway

Ulcerative colitis (UC) is a relapsing and remitting inflammatory bowel disease (IBD), but current conventional drugs lack efficacy. Astragalus polysaccharide (APS) is an active ingredient of Astragalus membranaceus and has been shown to ameliorate experimental colitis. In the present study, we aimed to investigate how APS affects the ferroptosis of intestinal epithelial cells in dextran sulfate sodium (DSS)-induced experimental colitis in mice. Our data showed that APS administration attenuated total weight loss, colon length shortening, disease activity index (DAI) scores, histological damage, and the expression of inflammatory cytokines in the colon of DSS-challenged mice. Moreover, we observed that treatment with APS obviously inhibited ferroptosis in both DSS-challenged mice and RSL3-stimulated Caco-2 cells, as indicated by the decrease in the expression of ferroptosis-associated genes (PTGS2, FTH, and FTL) and the levels of surrogate ferroptosis markers (MDA, GSH, and iron load). Mechanistically, the inhibitory effects of APS on ferroptosis in DSS-challenged mice and RSL3-stimulated Caco-2 cells were associated with the NRF2/HO-1 pathway. Collectively, our findings identify a new role of APS in preventing ferroptosis in a murine model of experimental colitis and human Caco-2 cells via inhibiting NRF2/HO-1 pathway.

PD-1 through Asparaginyl Endopeptidase Regulates Foxp3 Stability in Induced Regulatory T Cells

CD4+ T cell differentiation into multiple T helper lineages is critical for optimal adaptive immune responses. Lineage instability has been attributed to Tregs and Th17 cells but Th1 cells are acclaimed for their functional stability. In this report, we investigated the intrinsic mechanism by which PD-1 signaling imparted regulatory phenotype to Foxp3+ Th1 cells (denoted as Tbet+ iTregPDL1 cells). Tbet+iTregPDL1 cells were capable of preventing autoimmunity and alloimmunity in murine models of experimental colitis and experimental graft versus host disease (GvHD). PDL-1 binding to PD-1 imparted regulatory function to Tbet+iTregPDL1 cells by specifically down regulating the endo-lysosomal protease asparaginase endopeptidase (AEP). AEP cleaved Foxp3 in control Tbet+ iTregs and iTreg cells resulting in Foxp3 degradation. Blocking AEP, by knockdown and selective inhibitor, enhanced Foxp3 stability and regulatory function in Tbet+ iTreg cells. In addition, Aep-/- iTregs significantly inhibited GvHD and maintained Foxp3. Of note, PD-1 mediated Foxp3 maintenance in Tbet+ Th1 cells was significantly operational in tumor infiltrating lymphocytes. Collectively, this report has identified a novel intrinsic function for PD-1 in converting Th1 cells into Tregs through an intrinsic proteolytic pathway. DisclosuresNo relevant conflicts of interest to declare.

Echinochrome A Reduces Colitis in Mice and Induces In Vitro Generation of Regulatory Immune Cells.

Echinochrome A (Ech A), a natural pigment extracted from sea urchins, is the active ingredient of a marine-derived pharmaceutical called ‘histochrome’. Since it exhibits several biological activities including anti-oxidative and anti-inflammatory effects, it has been applied to the management of cardiac injury and ocular degenerative disorders in Russia and its protective role has been studied for other pathologic conditions. In the present study, we sought to investigate the therapeutic potential of Ech A for inflammatory bowel disease (IBD) using a murine model of experimental colitis. We found that intravenous injection of Ech A significantly prevented body weight loss and subsequent lethality in colitis-induced mice. Interestingly, T cell proliferation was significantly inhibited upon Ech A treatment in vitro. During the helper T (Th) cell differentiation process, Ech A stimulated the generation regulatory T (Treg) cells that modulate the inflammatory response and immune homeostasis. Moreover, Ech A treatment suppressed the in vitro activation of pro-inflammatory M1 type macrophages, while inducing the production of M2 type macrophages that promote the resolution of inflammation and initiate tissue repair. Based on these results, we suggest that Ech A could provide a beneficial impact on IBD by correcting the imbalance in the intestinal immune system.

Endoscopic Transplantation of Mesenchymal Stem Cell Sheets in Experimental Colitis in Rats

Owing to the recent progress in regenerative medicine technology, clinical trials that harnessed the regeneration and immune modulation potentiality of stem cells for treating IBD have shown promising results. We investigated the feasibility and utility of intraluminal endoscopic transplantation of rat MSC sheets in murine models of experimental colitis for targeted delivery of stem cells to lesions. We isolated adipose-derived mesenchymal stem cells (AD-MSC) and bone marrow-derived mesenchymal stem cells (BM-MSC) from EGFP-transgenic rats and fabricated the cells in sheet forms using temperature-responsive culture dishes. The MSC sheets were endoscopically transplanted to the inflamed area in electrocoagulation and DNBS colitis model. The effect of the transplantation was verified using endoscopic scoring and histological analysis. In the electrocoagulation model, the AD-MSC group showed significantly decreased ulcer size in the transplanted regions. In the DNBS colitis model, the AD-MSC group showed decreased inflammation and colitis in the transplanted regions. Histologic analysis showed that the MSC sheets had successfully attached to the inflamed mucosa in both the electrocoagulation and DNBS colitis model. Our results show that endoscopic transplantation of MSC sheets could be a new effective mode of stem cell therapy for IBD treatment.

PD-1 Inhibitory Receptor Downregulates Asparaginyl Endopeptidase and Maintains Foxp3 Transcription Factor Stability in Induced Regulatory T Cells

CD4+ Tcell differentiation into multiple T helper (Th) cell lineages is critical for optimal adaptive immune responses. This report identifies an intrinsic mechanism by which programmed death-1 receptor (PD-1) signaling imparted regulatory phenotype to Foxp3+ Th1 cells (denoted as Tbet+iTregPDL1 cells) and inducible regulatory T (iTreg) cells. Tbet+iTregPDL1 cells prevented inflammation in murine models of experimental colitis and experimental graft versus host disease (GvHD). Programmed death ligand-1 (PDL-1) binding to PD-1 imparted regulatory function to Tbet+iTregPDL1 cells and iTreg cells by specifically downregulating endo-lysosomal protease asparaginyl endopeptidase (AEP). AEP regulated Foxp3 stability and blocking AEP imparted regulatory function in Tbet+iTreg cells. Also, Aep-/- iTreg cells significantly inhibited GvHD and maintained Foxp3 expression. PD-1-mediated Foxp3 maintenance in Tbet+ Th1 cells occurred both in tumor infiltrating lymphocytes (TILs) and during chronic viral infection. Collectively, this report has identified an intrinsic function for PD-1 in maintaining Foxp3 through proteolytic pathway.

Inflamed site-specific drug delivery system based on the interaction of human serum albumin nanoparticles with myeloperoxidase in a murine model of experimental colitis

To develop a new strategy for inflamed site-specific drug delivery in the colon for the treatment of ulcerative colitis (UC), we leveraged on the interaction between myeloperoxidase (MPO) and human serum albumin (HSA) and prepared nanoparticles (HSA NPs) conjugated with 5-aminosalicylic acid (5-ASA). The 5-ASA-HSA NPs (nine molecules of 5-ASA per HSA molecule) were uniform particles with an average particle size of 190 nm, a zeta potential of -−11.8 mV, and a polydispersity index of 0.35. This was considered a suitable particle characteristic to pass through the mucus layer and accumulate into the mucosa. The specific interaction between the 5-ASA-HSA NPs and MPO was observed using quartz crystal microbalance analysis in vitro. In addition, the 5-ASA-HSA NPs group containing one thousandth of the dose of the 5-ASA (75 μg/kg) showed significantly lower disease activity index values and colon weight/length ratios in UC model mice as similar to large amount of neat 5-ASA group (75 mg/kg), indicating that the therapeutic effect of the 5-ASA-HSA NP formulation was confirmed in vivo. Microscopic images of tissue sections of colon extracted from UC model mice demonstrated that HSA NPs and MPO were both localized in the colon, and this specific interaction between HSA NPs and MPO would be involved the in the therapeutic effect in vivo. Furthermore, in the 5-ASA and 5-ASA-HSA NPs groups, some inflammatory damage was observed in the colon, but the degree of damage was mild compared with the control and HSA NPs groups, suggesting mucosal repair and replacement with fibrous granulation tissue had occurred. Therefore, these data demonstrated that an HSA NP formulation has the potential to specifically deliver 5-ASA to an inflamed site where MPO is highly expressed.

Vinegar Treatment Prevents the Development of Murine Experimental Colitis via Inhibition of Inflammation and Apoptosis.

This study investigated the preventive effects of vinegar and acetic acid (the active component of vinegar) on ulcerative colitis (UC) in mice. Vinegar (5% v/v) or acetic acid (0.3% w/v) treatment significantly reduced the disease activity index and histopathological scores, attenuated body weight loss, and shortened the colon length in a murine experimental colitis model induced by dextran sulfate sodium (DSS). Further mechanistic analysis showed that vinegar inhibited inflammation through suppressing Th1 and Th17 responses, the NLRP3 inflammasome, and MAPK signaling activation. Vinegar also inhibited endoplasmic reticulum (ER) stress-mediated apoptosis in the colitis mouse model. Surprisingly, pretreatment with vinegar for 28 days before DSS induction increased levels of the commensal lactic acid-producing or acetic acid-producing bacteria, including Lactobacillus, Bifidobacteria, and Enterococcus faecalis, whereas decreased Escherichia coli levels were found in the feces of mice. These results suggest that vinegar supplementation might provide a new dietary strategy for the prevention of UC.

Current understanding concerning intestinal stem cells.

In mammals, the intestinal epithelium is a tissue that contains two distinct pools of stem cells: active intestinal stem cells and reserve intestinal stem cells. The former are located in the crypt basement membrane and are responsible for maintaining epithelial homeostasis under intact conditions, whereas the latter exhibit the capacity to facilitate epithelial regeneration after injury. These two pools of cells can convert into each other, maintaining their quantitative balance. In terms of the active intestinal stem cells, their development into functional epithelium is precisely controlled by the following signaling pathways: Wnt/β-catenin, Ras/Raf/Mek/Erk/MAPK, Notch and BMP/Smad. However, mutations in some of the key regulator genes associated with these signaling pathways, such as APC, Kras and Smad4, are also highly associated with gut malformations. At this point, clarifying the biological characteristics of intestinal stem cells will increase the feasibility of preventing or treating some intestinal diseases, such as colorectal cancer. Moreover, as preclinical data demonstrate the therapeutic effects of colon stem cells on murine models of experimental colitis, the prospects of stem cell-based regenerative treatments for ulcerous lesions in the gastrointestinal tract will be improved all the same.

Diagnostic imaging advances in murine models of colitis.

Inflammatory bowel diseases (IBD) such as Crohn's disease and ulcerative colitis are chronic-remittent inflammatory disorders of the gastrointestinal tract still evoking challenging clinical diagnostic and therapeutic situations. Murine models of experimental colitis are a vital component of research into human IBD concerning questions of its complex pathogenesis or the evaluation of potential new drugs. To monitor the course of colitis, to the present day, classical parameters like histological tissue alterations or analysis of mucosal cytokine/chemokine expression often require euthanasia of animals. Recent advances mean revolutionary non-invasive imaging techniques for in vivo murine colitis diagnostics are increasingly available. These novel and emerging imaging techniques not only allow direct visualization of intestinal inflammation, but also enable molecular imaging and targeting of specific alterations of the inflamed murine mucosa. For the first time, in vivo imaging techniques allow for longitudinal examinations and evaluation of intra-individual therapeutic response. This review discusses the latest developments in the different fields of ultrasound, molecularly targeted contrast agent ultrasound, fluorescence endoscopy, confocal laser endomicroscopy as well as tomographic imaging with magnetic resonance imaging, computed tomography and fluorescence-mediated tomography, discussing their individual limitations and potential future diagnostic applications in the management of human patients with IBD.

Induction of Murine Intestinal Inflammation by Adoptive Transfer of Effector CD4+ CD45RB high T Cells into Immunodeficient Mice.

There are many different animal models available for studying the pathogenesis of human inflammatory bowel diseases (IBD), each with its own advantages and disadvantages. We describe here an experimental colitis model that is initiated by adoptive transfer of syngeneic splenic CD4(+)CD45RB(high) T cells into T and B cell deficient recipient mice. The CD4(+)CD45RB(high) T cell population that largely consists of naïve effector cells is capable of inducing chronic intestinal inflammation, closely resembling key aspects of human IBD. This method can be manipulated to study aspects of disease onset and progression. Additionally it can be used to study the function of innate, adaptive, and regulatory immune cell populations, and the role of environmental exposures, i.e., the microbiota, in intestinal inflammation. In this article we illustrate the methodology for inducing colitis with a step-by-step protocol. This includes a video demonstration of key technical aspects required to successfully develop this murine model of experimental colitis for research purposes.