Dextran Sulfate Sodium Administration Research Articles

Variation in the Efficacy of Anti-Ulcerative Colitis Treatments Reveals the Conflict Between Precipitating Compatibility of Traditional Chinese Medicine and Modern Technology: A Case of Scutellaria-Coptis.

Scutellariae and Coptidis compose a classical drug pair applied in clinical practice to dispel heat, dryness, and dampness, and they are also precipitation compatible drug pairs. With modern technology, Scutellaria-Coptis is mostly prepared by decocting its components separately, while in the traditional method, it is predominantly prepared as a combined decoction. The present study investigated the effects and mechanisms of separate and combined application of Scutellaria-Coptis decoction on ulcerative colitis (UC) in mice induced by the administration of dextran sulfate sodium (DSS). Changes in body weight, colon length, and Disease Activity Index scores were also evaluated. Hematoxylin and eosin staining and other methods were used to evaluate the overall condition of animals in each group. Intestinal microflora was analyzed using 16S rRNA sequencing, while colon inflammation and antioxidant capacity were evaluated based on the levels of interleukin-6 (IL-6), IL-10, IL-1β, tumor necrosis factor-α, superoxide dismutase, malondialdehyde, and reduced glutathione. The results revealed that Scutellaria-Coptis significantly relieved colon inflammation in mice, and the combined decoction of Scutellaria-Coptis exerted a significant effect on UC. Notably, the protective effect of Scutellaria-Coptis against colon inflammation was weakened when the antibiotic mixture was partially consumed by the gut microbiota. The results of 16S rRNA sequencing showed that the group treated with combined decoction of Scutellaria-Coptis exhibited a higher intestinal microbial diversity and intestinal flora composition than the separated decoction group. Treatment of mice with UC by administering Scutellaria-Coptis decoction through intestinal flora removal (ABX) and fecal microbial transplantation (FMT) was closely associated with intestinal flora composition. In conclusion, Scutellaria-Coptis can relieve UC with an excellent effect especially when taken as a combined decoction, alleviating colon inflammation incurred by intestinal microbes to a certain extent.

Wear and tear of the intestinal visceral musculature by intrinsic and extrinsic factors.

The gut visceral musculature plays essential roles in not only moving substances through the lumen but also maintaining the function and physiology of the gut. Although the development of the visceral musculature has been studied in multiple model organisms, how it degenerates is poorly understood. Here, we employ the Drosophila midgut as a model to demonstrate that the visceral musculature is disrupted by intrinsic and extrinsic factors, such as aging, feeding, chemical-induced tissue damage, and oncogenic transformation in the epithelium. Notably, we define four prominent visceral musculature disruption phenotypes, which we refer as "sprout," "discontinuity," "furcation," and "crossover" of the longitudinal muscle. Given that the occurrence of these phenotypes is increased during aging and under various stresses, we propose that these phenotypes can be used as quantitative readouts of deterioration of the visceral musculature. Intriguingly, administration of a tissue-damaging chemical dextran sulfate sodium (DSS) induced similar visceral musculature disruption phenotypes in zebrafish larvae, indicating that ingestion of a tissue-damaging chemical can disrupt the visceral musculature in a vertebrate as well. Our study provides insights into the deterioration of the gut visceral musculature and lays a groundwork for investigating the underlying mechanisms in Drosophila as well as other animals.

MiRNA-320 inhibits colitis-associated colorectal cancer by regulating the IL-6R/STAT3 pathway in mice.

Colitis-associated colorectal cancer (CAC) is a serious complication of inflammatory bowel disease (IBD). microRNA-320 (miRNA-320) promotes intestinal mucosal barrier repair in IBD and inhibits tumor progression. However, the role of miRNA-320 in the progression of CAC remains to be defined. We studied the mechanisms of miRNA-320 in the progression of CAC in mice. CAC was induced in mice (C57BL/B6) by the administration of azoxymethane (AOM) and dextran sulfate sodium (DSS), and the mice were given a lentiviral vector (LV) overexpressing mmu-miRNA-320. The level of miRNA-320 was analyzed by quantitative real-time polymerase chain reaction (qPCR). Colonic inflammation, histological analysis, and tumorigenesis were evaluated. Ki-67 in colonic tissues was examined by immunohistochemistry. B-cell lymphoma-extra large (BCL-xl) and proliferating cell nuclear antigen (PCNA) expression was examined by Western blot. Furthermore, the proliferation, migration, and invasion of colorectal cancer (CRC) cells were evaluated. The levels of interleukin-6 receptor (IL-6R), signal transducer and activator of transcription 3 (STAT3), and phosphorylated-signal transducer and activator of transcription 3 (p-STAT3) were examined by Western blot and qPCR. miRNA-320 was downregulated in CAC mice (0.57±0.13 vs. 1.00±0.12, t=-5.95, P<0.001). miRNA-320 decreased the disease activity index (DAI) scores, improved colonic inflammation, and inhibited tumor formation (tumor number: 8.00±2.90 vs. 13.67±2.73, t=-3.49, P<0.01) in mice with CAC. miRNA-320 suppressed the expression of BCL-xl, PCNA, and Ki-67 (0.38±0.07 vs. 0.69±0.08, t=-7.30, P<0.001). miRNA-320 inhibited colon cancer cell proliferation, migration, and invasion. miRNA-320 significantly inhibited the levels of IL-6R [colon tissue messenger RNA (mRNA): 4.06±1.44 vs. 10.05±1.55, t=-6.94, P<0.001], STAT3, and p-STAT3 in vivo and in vitro. Silencing IL-6R expression partially reversed the IL-6R/STAT3-suppressing and tumor-inhibiting effect of miRNA-320. miRNA-320 inhibits tumorigenesis in mice with CAC by suppressing IL-6R/STAT3 expression, and IL-6R is a target gene of miRNA-320.

Crocetin Prolongs Recovery Period of DSS-Induced Colitis via Altering Intestinal Microbiome and Increasing Intestinal Permeability.

Crocetin is one of the major active constituents of saffron (Crocus sativus L.) which has a reputation for facilitating blood circulation and dispersing blood stasis in traditional Chinese medicine. However, there is little evidence showing the relationship between crocetin intake and the risk of gastrointestinal diseases such as colitis. In order to investigate the effect of crocetin on the regulation of intestinal barrier function and intestinal microbiota composition, mice were treated with crocetin after 3% dextran sulfate sodium (DSS) administration for one week. We found that crocetin intake at 10 mg/kg aggravated colitis in mice, showing increased weight loss and more serious histological abnormalities compared with the DSS group. The 16s rDNA sequencing analysis of the feces samples showed that mice treated with 10 mg/kg crocetin had lower species diversity and richness than those treated with DSS. At the genus level, a higher abundance of Akkermansia and Mediterraneibacter, and a lower abundance of Muribaculaceae, Dubosiella, Paramuribaculum, Parasutterella, Allobaculum, Duncaniella, Candidatus Stoquefichus, and Coriobacteriaceae UCG-002 were observed in the crocetin group. Untargeted metabolomic analyses revealed that crocetin reduced the levels of primary and secondary bile acids such as 12-ketodeoxycholic acid, 7-ketodeoxycholic acid, 3-sulfodeoxycholic acid, 6-ethylchenodeoxycholic acid, chenodeoxycholate, glycochenodeoxycholate-7-sulfate, glycocholate, and sulfolithocholic acid in the colon. In conclusion, crocetin intake disturbed intestinal homeostasis and prolonged recovery of colitis by promoting inflammation and altering gut microbiota composition and its metabolic products in mice. Our findings suggest that patients with gastrointestinal diseases such as inflammatory bowel disease should use crocetin with caution.

Hydroxysafflor yellow A protects against ulcerative colitis via suppressing TLR4/NF-κB signaling pathway.

Hydroxysafflower yellow A (HSYA) protects against acute kidney injury through TLR4/NF-κB pathway. However, the effect and potential mechanism of HSYA in ulcerative colitis (UC) have been rarely reported, which is thus investigated in this research. An in vivo UC model was established by oral administration of 5% dextran sulfate sodium (DSS) in Sprague-Dawley rats. After HSYA treatment, the daily body weight and colon length of rats were measured. Then rat colon tissues, myeloperoxidase (MPO) activity, and the levels of inflammatory cytokines were examined by histopathological examination (HE) staining, immunohistochemistry, ultraviolet spectrophotometry, and enzyme-linked immune sorbent assay (ELISA) respectively. The activated TLR4/NF-κB pathway was detected by Western blot. RAW 264.7 cell viability was detected by MTT assay after lipopolysaccharide (LPS) treatment, and ELISA and Western blot were performed again to investigate the effects of HSYA on LPS-treated cells. DSS administration increased body weight and colon length of rats and induced colon tissue injury. DSS or LPS treatment up-regulated the levels of TNF-α, IL-1β, and IL-6 and activated TLR4/NF-κB pathway of colon tissues and cells, respectively. HSYA partially reversed the above effect of DSS and LPS treatment, and the effects of the drug were improved with the dosage. Taken together, HSYA alleviates UC by suppressing TLR4/NF-κB signaling pathway, which may provide a new insight for the treatment of UC.

On the development of a neoantigen vaccine for the prevention of Lynch Syndrome

Lynch Syndrome (LS) is an autosomal dominant genetic condition that causes a high risk of colorectal cancer. The hallmark of LS is genetic instability as a result of mismatch repair (MMR) deficiency, particularly in repetitive low complexity regions called microsatellites (MS). MLH1-/- mice deficient in MMR are prone to developing tumors in the colon, upon oral administration of dextran sodium sulfate (DSS), at a rate of more than 70%. Using this LS mouse model, we found a novel tumor neo-antigen from a deletion mutation of the coding MS in the SENP6 gene that prevented tumorigenesis or hindered tumor growth rate in immunized mice. This was accomplished via high throughput exome sequencing of DSS-induced colorectal tumors in the MLH1-/- mice and predicting the most highly immunogenic mutant gene products processed and presented as antigens in C57BL/6 MHC-I molecules. Throughout our study, we were able to prove the validity of the vaccine by analyzing the colorectal tumors in immunized DSS-treated mice using either our epitope, called Sp6D1, or an unrelated peptide as a negative control. Tumors developed in this context were found to be antigenic and Sp6D1-specific CD8+ tumor infiltrating lymphocytes were detected by flow cytometry and cytotoxic T lymphocytes (CTL) killing assays. Additionally, immunohistochemistry showed that tumor-adjacent tertiary lymphoid organs were a potentially significant source of CD8+ lymphocytes. Altogether, our results indicate that there may be a protective effect to patients carrying LS mutations through the induction of a peptide-specific CTL response from the use of neoepitope vaccination.

Structural Characteristics of Inulin and Microcrystalline Cellulose and Their Effect on Ameliorating Colitis and Altering Colonic Microbiota in Dextran Sodium Sulfate-Induced Colitic Mice.

Several studies have reported that dietary fibers (DFs) from plants may exert beneficial effects on inflammatory bowel disease. In the present study, we investigated the structural differences of soluble DF (inulin) and insoluble DF (microcrystalline cellulose, MCC) and their effects on the intestinal barrier integrity, gut microbiota community, and inflammation response in mice with dextran sodium sulfate (DSS)-induced colitis. Mice were fed for 21 days with diets containing inulin or MCC (2.5 g/kg body weight), and colitis was induced by administration of DSS (4% w/v) in drinking water during the last 8 days of experimentation. The results showed that inulin and MCC differ in morphology and structure. MCC exhibited a smaller particle size, a larger specific surface area, and higher thermal stability than inulin. In addition, both inulin and MCC restored various physical signs (body weight, colon weight and length, disease activity index score, and infiltration of inflammatory cells), gut barrier function (as evidenced by the increased expression of claudin-3, claudin-7, ZO-2, occludin, JAM-2, and MUC-3 and the decreased activity of myeloperoxidase activity), downregulation of mRNA expression of proinflammatory cytokines (caspase-1, NLPR3, TLR4, TNF-α, and IL-1β), and modulation of colon microbiota community. Taken together, the present study demonstrates that DFs differ in morphology and structure and ameliorate DSS-induced colitis in mice by blocking proinflammatory cytokines, reinforcing gut barrier integrity, and modulating gut microbiota. Therefore, DFs, especially inulin, are promising dietary supplements to alleviate intestinal inflammation.

Baccharis dracunculifolia DC Hydroalcoholic Extract Improves Intestinal and Hippocampal Inflammation and Decreases Behavioral Changes of Colitis Mice.

The hydroalcoholic extract of B. dracunculifolia (HEBD) and its major compound p-coumaric acid were evaluated against the severity of intestinal inflammation and behavioral changes like depressive and anxious behavior in colitis mice. Colitis was induced in Swiss mice by oral dextran sulfate sodium (DSS) administration for five days. The mice received vehicle (10 ml/kg), HEBD (3, 30, or 300 mg/kg), or p-coumaric acid (15 mg/kg) orally, once a day for twelve days. Behavioral tests were performed on the 11th and 12th days after the beginning of the treatments. Moreover, the colon, cortex, and hippocampus were collected to analyze oxidative and inflammatory parameters. The treatment with HEBD (300 mg/Kg), but not p-coumaric acid, showed decreased disease activity index (DAI) values compared to the vehicle group and partially preserved the villi architecture and mucin levels. Furthermore, the HEBD increased the antioxidant defenses in the colon and hippocampus and reduced the myeloperoxidase activity and IL-6 levels in the colon from colitis mice. Colitis mice treated with HEBD did not show depressive-like behavior in the tail suspension test. HEBD reduced colon inflammation, while it maintains antioxidant defenses and mucin levels in this tissue. It may reduce neuropsychiatric comorbidities associated with colitis through its antioxidant effects.

A High-Fat Western Diet Attenuates Intestinal Changes in Mice with DSS-Induced Low-Grade Inflammation

BackgroundA Western diet (WD) is associated with increased inflammation in the large intestine, which is often ascribed to the high dietary fat content. Intestinal inflammation in rodents can be induced by oral administration of dextran sodium sulfate (DSS). However, most studies investigating effects of WD and DSS have not used appropriate low-fat diets (LFDs) as control. ObjectivesTo compare the effects of a WD with those of an LFD on colon health in a DSS-induced low-grade colonic inflammation mouse model. MethodsSix-week-old male C57BL/6JRj mice were fed an LFD (fat = 10.3% energy, n = 24) or a WD (fat = 41.2% energy, n = 24) for 15 wk [Experiment 1 (Exp.1)]. Half the mice on each diet (n = 12) then received 1% DSS in water for 6 d with the remainder (n = 12 in each diet) administered water. Disease activity, proinflammatory genes, inflammatory biomarkers, and fecal microbiota (16S rRNA) were assessed (Exp.1). Follow-up experiments (Exp.2 and Exp.3) were performed to investigate whether fat source (milk or lard; Exp.2) affected outcomes and whether a shift from LFD to WD 1 d prior to 1% DSS exposure caused an immediate effect on DSS-induced inflammation (Exp.3). ResultsIn Exp.1, 1% DSS treatment significantly increased disease score in the LFD group compared with the WD group (2.7 compared with 0.8; P < 0.001). Higher concentrations of fecal lipocalin (11-fold; P < 0.001), proinflammatory gene expression (≤82-fold), and Proteobacteria were observed in LFD-fed mice compared with the WD group. The 2 fat sources in WDs (Exp.2) revealed the same low inflammation in WD+DSS mice compared with LFD+DSS mice. Finally, the switch from LFD to WD just before DSS exposure resulted in reduced colonic inflammation (Exp.3). ConclusionsHerein, WDs (with milk or lard) protected mice against DSS-induced colonic inflammation compared with LFD-fed mice. Whether fat intake induces protective mechanisms against DSS-mediated inflammation or inhibits establishment of the DSS-induced colitis model is unclear.

Convallatoxin inhibits IL-1β production by suppressing zinc finger protein 91 (ZFP91)-mediated pro-IL-1β ubiquitination and caspase-8 inflammasome activity.

ZFP91 positively regulates IL-1β production in macrophages and may be a potential therapeutic target to treat inflammatory-related diseases. We investigated whether this process is modulated by convallatoxin, which is a cardiac glycoside isolated from the traditional Chinese medicinal plant Adonis amurensis Regel et Radde. In vitro, the mechanisms by which convallatoxin inhibits ZFP91-regulated IL-1β expression were investigated using molecular docking, western blotting, RT-PCR, ELISA, immunofluorescence and immunoprecipitation assays.In vivo, mice liver injury was induced by an intraperitoneal injection of D-GalN and LPS, colitis was induced by oral administration of dextran sulfate sodium (DSS) in drinking water and peritonitis was induced by an intraperitoneal injection of alum. We confirmed that convallatoxin inhibited the release of IL-1β by down-regulating ZFP91. Importantly, we found that convallatoxin significantly reduced K63-linked polyubiquitination of pro-IL-1β regulated by ZFP91 and decreased the efficacy of pro-IL-1β cleavage. Moreover, convallatoxin suppressed ZFP91-mediated activation of the non-canonical cysteine-requiring aspartate protease-8 (caspase-8) inflammasome and MAPK signalling pathways in macrophages. Furthermore, we showed that ZFP91 promoted the assembly of the caspase-8 inflammasome complex, whereas convallatoxin treatment reversed this result. Mice in vivo studies further demonstrated that convallatoxin ameliorated D-GalN/LPS-induced liver injury, DSS-induced colitis and alum-induced peritonitis by down-regulating ZFP91. We show for the first time that convallatoxin-mediated inhibition of ZFP91 is an important regulatory event that prevents inappropriate inflammatory responses to maintain immune homeostasis. This mechanism provides new insight for the development of convallatoxin as a novel anti-inflammatory drug targeting ZFP91. This article is part of a themed issue on Inflammation, Repair and Ageing. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v179.9/issuetoc.

Dandelion root extracts abolish MAPK pathways to ameliorate experimental mouse ulcerative colitis.

Dextran sodium sulfate (DSS)-triggered ulcerative colitis (UC) model in animals provides a valuable platform to preclinically evaluate the outcome of drug candidates for UC. Dandelion root extracts (DRE) have a therapeutic effect on UC. However, the protective mechanism of DRE against UC remains unknown. To discover the targeting pathway involved in DRE-induced protection against UC. The UC model was developed in C57BL/6 mice by oral administration of DSS. Following DSS exposure, sulfasalazine (SASP), low dose of DRE (DRE-L), moderate dose of DRE (DRE-M), high dose of DRE (DRE-H), and DRE-H plus mitogen-activated protein kinases (MAPK) agonist (DRE-H+MA) were administered to the mice. Colon Mucosal Damage Index (CMDI) and histopathological analysis were used to evaluate the colonic mucosal damage. The cytokine levels were detected using commercial enzyme-linked immunosorbent assay (ELISA) kits. The MAPK pathway activation was determined with western blotting. We found that DRE-H attenuated DSS-triggered colonic mucosal damage. The DSS-induced inflammatory responses and oxidative stress in the bloodstream and colon tissues were dramatically inhibited by DRE-H administration. Also, this plant impaired DSS-provoked phosphorylation levels of extracellular signal-regulated kinases (ERK), c-Jun N-terminal kinases (JNK), p38 mitogen-activated protein kinases (p38), p65, and IκB. More importantly, MAPK agonist, BIM-23A760, removed the protective effect of DRE-H on the bloodstream and colon tissues. The DRE-H is capable of relieving DSS-induced UC, and its mechanism links to the MAPK pathways.

Transplantation of intestinal organoids into a mouse model of colitis.

Intestinal organoids are fundamental in vitro tools that have enabled new research opportunities in intestinal stem cell research. Organoids can also be transplanted in vivo, which enables them to probe stem cell potential and be used for disease modeling and as a preclinical tool in regenerative medicine. Here we describe in detail how to orthotopically transplant epithelial organoids into the colon of recipient mice. In this assay, epithelial injury is initiated at the distal part of colon by the administration of dextran sulfate sodium, and organoids are infused into the luminal space via the anus. The infused organoids subsequently attach to the injured region and rebuild a donor-derived epithelium. The steps for cell infusion can be completed in 10 min. The assay has been applied successfully to organoids derived from both wild-type and genetically altered epithelial cells from adult colonic and small intestinal epithelium, as well as fetal small intestine. This is a versatile protocol, providing the technical basis for transplantation following alternative colonic injury models. It has been used previously for functional assays to probe cellular potential, and formed the basis for the first in-human clinical trial using colonic organoid transplantation therapy for intractable cases of ulcerative colitis.

Dietary Alaska Pollock Protein Attenuates the Experimental Colitis Induced by Dextran Sulfate Sodium via Regulation of Gut Microbiota and Its Metabolites in Mice.

Protein derived from fish has not only nutritional properties but also health-promoting properties. Few studies have examined the effect of dietary Alaska pollock protein (APP) on the anticolitis effect reported to be associated with metabolic syndrome (MetS). This study investigated the effect of APP intake on colitis symptoms, gut microbiota, and its metabolites in the experimental colitis mouse model induced by dextran sulfate sodium (DSS). Male C57BL/6J mice were divided into three groups: (1) DSS-untreated mice fed an American Institute of Nutrition (AIN) 93G diet (protein source is casein), (2) DSS-treated mice fed an AIN93G diet, and (3) DSS-treated mice fed an APP diet. After the mice were fed the diets for 21 days, experimental colitis was induced by three cycles of 2% DSS administration for 5 days followed by washouts over the course of 5 days. APP-reduced body weight loss increased the disease activity index, and elevated spleen weight and alleviated colon length shortening and colonic tissue damage. Furthermore, APP altered the structure and composition of the microbiota and short-chain fatty acids in feces. Since APP intake alleviates experimental colitis induced by DSS administration through alterations in the gut microbiota and its metabolites, we deduced that APP would inhibit MetS progression via colitis suppression.

Anemone chinensis Bunge aqueous enema alleviates dextran sulfate sodium-induced colitis via inhibition of inflammation and regulation of the colonic mucosal microbiota

Ethnopharmacological relevanceAlthough the incidence of ulcerative colitis (UC) increases every year, there is still a lack of satisfactory treatment options. Anemone chinensis Bunge (AB), a traditional Chinese herb, is a potent compound that can be prepared as a decoction, and then administered as an enema to relieve UC symptoms. However, the therapeutic effect and mechanisms of aqueous AB on UC are still unknown.Aim of the study: This study investigates the potential therapeutic value and mechanism of AB aqueous enema for UC. Materials and methodsFirst, the practical components in aqueous AB were extracted and identified by UPLC-MS/MS. Second, the potential active targets and target genes related to UC were predicted, mapped, and analyzed by network pharmacology. Then, the effects of AB aqueous enema on UC were assessed using the dextran sulfate sodium (DSS)-induced colitis model with mice. Finally, the level of inflammation, the expression level of proteins associated with the colonic mucosal barrier, and the microbiota associated with the intestinal mucosal were investigated. ResultsFourteen active ingredients in AB were identified. The network pharmacology-based analysis demonstrated that the active ingredients possibly affected ten key targets, such as IL-6, TNF, and PTGS2. They are also related to the tight junction proteins ZO-1, occludin, and claudin-1.Furthermore, mice treated with DSS developed severe mucosal colitis. AB aqueous enema decreased the disease activity index (DAI), significantly inhibited colonic damage, and greatly decreased colon length shortening (p < 0.05).AB also significantly restored tight junction proteins and the associated mucin proteins mucin-2 (MUC2) and mucin-3A (MUC3A). In addition, the diversity of the gut microbiota after administration of DSS was significantly decreased. However, the diversity was entirely restored after AB treatment. Recovery of the abundance of colonic mucosal bacteria, especially Lactobacillus reuteri and Lactobacillus gasseri, occurred at the species level after AB treatment. In vitro, AB can be utilized by the two bacteria, especially under glucose deficiency. ConclusionsOur study demonstrated that the AB aqueous enema alleviated colitis by restoring intestinal barrier proteins and regulating the gut microbiota.

Protective Effect of Probiotics Isolated from Traditional Fermented Tea Leaves (Miang) from Northern Thailand and Role of Synbiotics in Ameliorating Experimental Ulcerative Colitis in Mice.

This study aimed to investigate the protective effect of probiotics and synbiotics from traditional Thai fermented tea leaves (Miang) on dextran sulfate sodium (DSS)-induced colitis in mice, in comparison to sulfasalazine. C57BL/6 mice were treated with probiotics L. pentosus A14-6, CMY46 and synbiotics, L. pentosus A14-6 combined with XOS, and L. pentosus CMY46 combined with GOS for 21 days. Colitis was induced with 2% DSS administration for seven days during the last seven days of the experimental period. The positive group was treated with sulfasalazine. At the end of the experiment, clinical symptoms, pathohistological changes, intestinal barrier integrity, and inflammatory markers were analyzed. The probiotics and synbiotics from Miang ameliorated DSS-induced colitis by protecting body weight loss, decreasing disease activity index, restoring the colon length, and reducing pathohistological damages. Furthermore, treatment with probiotics and synbiotics improved intestinal barrier integrity, accompanied by lowing colonic and systemic inflammation. In addition, synbiotics CMY46 combined with GOS remarkedly elevated the expression of IL-10. These results suggested that synbiotics isolated from Miang had more effectiveness than sulfasalazine. Thereby, they could represent a novel potential natural agent against colonic inflammation.

Facilitation of colonic T cell immune responses is associated with an exacerbation of dextran sodium sulfate\u2013induced colitis in mice lacking microsomal prostaglandin E synthase-1

BackgroundMicrosomal prostaglandin E synthase-1 (mPGES-1) is a key enzyme that acts downstream of cyclooxygenase and plays a major role in inflammation by converting prostaglandin (PG) H2 to PGE2. The present study investigated the effect of genetic deletion of mPGES-1 on the development of immunologic responses to experimental colitis induced by dextran sodium sulfate (DSS), a well-established model of inflammatory bowel disease (IBD).MethodsColitis was induced in mice lacking mPGES-1 (mPGES-1−/− mice) and wild-type (WT) mice by administering DSS for 7 days. Colitis was assessed by body weight loss, diarrhea, fecal bleeding, and histological features. The colonic expression of mPGES-1 was determined by real-time PCR, western blotting, and immunohistochemistry. The impact of mPGES-1 deficiency on T cell immunity was determined by flow cytometry and T cell depletion in vivo.ResultsAfter administration of DSS, mPGES-1−/− mice exhibited more severe weight loss, diarrhea, and fecal bleeding than WT mice. Histological analysis further showed significant exacerbation of colonic inflammation in mPGES-1−/− mice. In WT mice, the colonic expression of mPGES-1 was highly induced on both mRNA and protein levels and colonic PGE2 increased significantly after DSS administration. Additionally, mPGES-1 protein was localized in the colonic mucosal epithelium and infiltrated inflammatory cells in underlying connective tissues and the lamina propria. The abnormalities consistent with colitis in mPGES-1−/− mice were associated with higher expression of colonic T-helper (Th)17 and Th1 cytokines, including interleukin 17A and interferon-γ. Furthermore, lack of mPGES-1 increased the numbers of Th17 and Th1 cells in the lamina propria mononuclear cells within the colon, even though the number of suppressive regulatory T cells also increased. CD4+ T cell depletion effectively reduced symptoms of colitis as well as colonic expression of Th17 and Th1 cytokines in mPGES-1−/− mice, suggesting the requirement of CD4+ T cells in the exacerbation of DSS-induced colitis under mPGES-1 deficiency.ConclusionsThese results demonstrate that mPGES-1 is the main enzyme responsible for colonic PGE2 production and deficiency of mPGES-1 facilitates the development of colitis by affecting the development of colonic T cell–mediated immunity. mPGES-1 might therefore impact both the intestinal inflammation and T cell–mediated immunity associated with IBD.

MyD88 Mediates Colitis- and RANKL-Induced Microfold Cell Differentiation.

Intestinal microfold (M) cells are critical for sampling antigens in the gut and initiating the intestinal mucosal immune response. In this study, we found that the oral administration of dextran sulfate sodium (DSS) and Salmonella infection induced colitis. In the process, the expression levels of M cell differentiation-related genes were synchronized with the kinetics of pro-inflammatory cytokines. Compared to wild-type (WT) mice, MyD88−/− mice exhibited significantly lower expression levels of M cell differentiation-related genes. However, DSS induced colitis in MyD88−/− mice but failed to promote the transcription of M cell differentiation related genes. Furthermore, the receptor activator of the Nuclear Factor-κB ligand (RANKL) upregulated the transcription of M cell differentiation related genes in murine intestinal organoids prepared from both WT and MyD88−/− mice. Meanwhile, fewer changes in M cell differentiation related genes were found in MyD88−/− mice as compared to WT mice. Hence, we concluded that myeloid differentiation factor 88 (MyD88) is an essential molecule for colitis- and RANKL-related differentiation of M cells.

Recombinant protein Schistosoma japonicum-derived molecule attenuates dextran sulfate sodium-induced colitis by inhibiting miRNA-217-5p to alleviate apoptosis.

BACKGROUNDInflammatory bowel disease (IBD) affects millions of people worldwide and has emerged as a growing problem in industrialized nations. The lack of therapeutic targets has limited the treatment of IBD. Studies found that parasitic nematode infections can ameliorate clinical and experimental colitis. Our previous study found that rSj16, a 16-kDa secreted protein of Schistosoma japonicum produced by Escherichia coli, has protective effects on dextran sulfate sodium (DSS)-induced colitis in mice. Apoptosis is an important factor in the pathogenesis of colitis. However, it is not clear whether the effect of rSj16 on colitis is related to apoptosis.AIMTo investigate whether the protective effects of rSj16 on colitis is related to apoptosis and its mechanism.METHODS In-vivo , colitis was induced by DSS. The severity of colitis was assessed. WB was used to detect the changes of apoptosis-related genes in colon tissues. Q-PCR was used to detect the changes of miRNA-217-5p and HNF1B. In-vitro, WB was used to detect the changes of apoptosis-related genes in intestinal epithelial cells. TUNNEL staining and flow cytometry were used to detect cell apoptosis.RESULTSrSj16 attenuates clinical activity in DSS-induced colitis mice. TUNNEL staining and WB results showed that apoptosis was increased in colon tissue after treatment with DSS, and the apoptosis of colon tissue was significantly reduced after treatment with rSj16. Compared with normal mice, the expression of miR-217-5p was increased in colon tissue of DSS-induced colitis mice. In addition, the miR-217-5p target gene hnf1b was decreased after administration of DSS. After treatment with rSj16, the expression of miR-217-5p was decreased and the expression of HNF1B was increased compared with the DSS-treated group. When Etoposide was used in combination with miR-217-5p mimic on MODE-K cells, the expression of cleaved-Caspase-3 and Bax was increased, and Bcl-2 was decreased compared with only Etoposide treatment, the expression of HNF1B was significantly reduced, suggesting that miR-217-5p acts as a pro-apoptotic in colon epithelial cells and down-regulates the target gene hnf1b. After rSj16 administration in MODE-K cells, miR-217-5p expression was significantly decreased, HNF1B expression was increased, and apoptosis was reduced.CONCLUSIONThe protective effects of rSj16 on colitis is related to apoptosis and miRNA-217-5p may be a further target for therapeutic intervention against IBD.

Dextran sulfate sodium-induced colitis in C57BL/6J mice increases their susceptibility to chronic unpredictable mild stress that induces depressive-like behavior

AimsIn patients with colitis, the high comorbidity of depressive disorders is well-known, but the detailed mechanisms remain unresolved. In this study, we examined whether colitis induced by dextran sulfate sodium (DSS) increased the susceptibility to chronic unpredictable mild stress (CUMS) in C57BL/6J mice with resilience to CUMS. Main methodsTo induce experimental colitis and depressive-like behaviors, male 7-weeks old C57BL/6J mice were administered ad libitum 1% DSS solution for 11 days, and subjected to various mild stressors in a chronic, inevitable and unpredictable way according to a random schedule for 21 days, respectively. Key findingsIn naïve mice exposed to CUMS, their immobility times in a forced swim (FS) test were almost equal to those in control mice. The DSS administration to naïve mice induced colitis without depressive-like behavior, and at 18 days after termination of the DSS administration, the colitis had recovered to control levels, while altered diversity and composition of bacterial genera such as Bacteroides spp., Alistipes spp., etc., were found in the gut microbiota. Exposure of mice with DSS-induced colitis to CUMS (DSS + CUMS) significantly increased the immobility times in the FS test. In the gut microbiota of DSS + CUMS mice, the alteration profile of the relative abundance of bacterial genera differed from in the DSS ones. SignificanceThese findings indicate that mice with colitis exhibit increased susceptibility to psychological stress, resulting in induction of depressive-like behavior, and this might be due, at least in part, to altered characteristics of the gut microbiota.

Candida tropicalis Infection Modulates the Gut Microbiome and Confers Enhanced Susceptibility to Colitis in Mice.

Background & AimsWe previously showed that abundance of Candida tropicalis is significantly greater in Crohn’s disease patients compared with first-degree relatives without Crohn’s disease. The aim of this study was to determine the effects and mechanisms of action of C tropicalis infection on intestinal inflammation and injury in mice.MethodsC57BL/6 mice were inoculated with C tropicalis, and colitis was induced by administration of dextran sodium sulfate in drinking water. Disease severity and intestinal permeability subsequently were evaluated by endoscopy, histology, quantitative reverse-transcription polymerase chain reaction, as well as 16S ribosomal RNA and NanoString analyses (NanoString Technologies, Seattle, WA).ResultsInfected mice showed more severe colitis, with alterations in gut mucosal helper T cells (Th)1 and Th17 cytokine expression, and an increased frequency of mesenteric lymph node–derived group 2 innate lymphoid cells compared with uninfected controls. Gut microbiome composition, including changes in the mucin-degrading bacteria, Akkermansia muciniphila and Ruminococcus gnavus, was altered significantly, as was expression of several genes affecting intestinal epithelial homeostasis in isolated colonoids, after C tropicalis infection compared with uninfected controls. In line with these findings, fecal microbiome transplantation of germ-free recipient mice using infected vs uninfected donors showed altered expression of several tight-junction proteins and increased susceptibility to dextran sodium sulfate–induced colitis.ConclusionsC tropicalis induces dysbiosis that involves changes in the presence of mucin-degrading bacteria, leading to altered tight junction protein expression with increased intestinal permeability and followed by induction of robust Th1/Th17 responses, which ultimately lead to an accelerated proinflammatory phenotype in experimental colitic mice.