Dextran Sulfate Sodium-induced Colitis Research Articles

The Hydrophobic Amino Acid-Rich Fish Collagen Peptide Ameliorates Dextran Sulfate Sodium-Induced Ulcerative Colitis in Mice via Repairing the Intestinal Barrier, Regulating Intestinal Flora and AA Metabolism.

The incidence of ulcerative colitis (UC) is increasing annually, but treatment option is limited. Fish collagen peptide (FCP) is a food source collagen peptide that has shown promise in alleviating UC symptoms. However, its impact on the intestinal barrier and intestinal metabolic homeostasis in UC remains unclear. This study aimed to analyze the peptide sequences and absolute amino acid (AA) content of FCP, assessing its effects on UC in mice induced by dextran sulfate sodium (DSS). FCP was examined by liquid chromatography and tandem mass spectrometry (LC-MS/MS) analysis. The 3% DSS was utilized to induce UC in murine models, followed by the assessment of the therapeutic efficacy of FCP. Clinical manifestations of UC mice were meticulously evaluated and scored. Subsequently, samples were procured for histological examination and intestinal epithelial barrier integrity analysis as well as macrogenomic and metabolomic profiling. Here, it shows that abundant peptide sequences and AAs were in FCP, particularly enriched in hydrophobic AAs (HAAs). Furthermore, it was observed that FCP effectively reversed colon shortening and reduced the extent of histological damage. Additionally, FCP suppressed the abnormal expression of inflammatory factors and intestinal barrier proteins and modulated the dysbiosis of gut microbiota toward a balanced state. These alterations led to the activation of intestinal alkaline AA and various AA metabolisms, ultimately contributing to the mitigation of UC symptoms. In summary, the diverse peptide sequences and high AAs in FCP, particularly rich in HAAs, can alleviate DSS-induced UC via preserving intestinal barrier integrity, regulating gut microbiota, and modulating AA metabolism.

Functional analysis of antigen presentation by enteric glial cells during intestinal inflammation.

The Enteric Nervous System is composed of a vastly interconnected network of neurons and glial cells that coordinate to regulate homeostatic gut function including intestinal motility, nutrient sensing, and mucosal barrier immunity. Enteric Glial Cells (EGCs) are a heterogeneous cell population located throughout the gastrointestinal tract and have well described roles in regulating intestinal immune responses. Enteric Glial Cells have been suggested to act as nonconventional antigen presenting cells via the Major Histocompatibility Complex II (MHC II), though this has not been confirmed functionally. Here, we investigate the capability of EGCs to present antigen on MHC I and MHC II using in vitro antigen presentation assays performed with primary murine EGC cultures. We found that EGCs are capable of functional antigen presentation on MHC I, including antigen cross-presentation, but are not capable of functional antigen presentation on MHC II. We also determined EGC cell surface MHC I and MHC II expression levels by flow cytometry during intestinal inflammation during Dextran Sodium Sulfate-induced colitis or acute Toxoplasma gondii infection. We found that EGCs upregulate MHC I during acute T. gondii infection and induce low-level MHC II expression. These findings suggest that EGCs may be important in the regulation of CD8+ T cell responses via MHC I mediated antigen (cross) presentation but may not be relevant for MHC II-mediated antigen presentation.

Poria cocos polysaccharides alleviate dextran sulphate sodium-induced ulcerative colitis in mice by modulating intestinal inflammatory responses and microbial dysbiosis

Poria cocos polysaccharide (PCP), one of the main active components of P. cocos, is extensively used worldwide and exhibits strong pharmacological effects. However, whether PCP can attenuate inflammatory bowel disease remains unclear. In this study, we assessed the effects of PCP supplementation on dextran sulphate sodium (DSS)-induced ulcerative colitis (UC) in mice. We found that PCP supplementation mitigated UC symptoms in DSS-treated mice, as evidenced by reductions in body weight loss, colon length shortening and disease activity index score. Importantly, PCP supplementation enhanced colonic barrier integrity by increasing tight junction protein abundance and exerted anti-inflammatory effects by suppressing nuclear factor-κB (NF-κB) activation in DSS-treated mice. Furthermore, PCP supplementation reversed DSS-induced dysbiosis in colonic microbiota by increasing the colonic abundance of beneficial bacteria (e.g. Akkermansiaceae) and decreasing the colonic abundance of harmful bacteria (e.g. Erysipelotrichaceae) in DSS-treated mice. Although PCP supplementation failed to ameliorate DSS-induced UC in antibiotic-treated mice, faecal microbiota transplantation from PCP-administered mice ameliorated DSS-induced UC in antibiotic-treated mice. In summary, PCP alleviates UC in mice by attenuating intestinal inflammation via the inhibition of NF-κB activation and modulating the intestinal microbiota.

Exploring the roles of SPARC as a proinflammatory factor and its potential as a novel therapeutic target against cardiovascular disease.

Cardiovascular disease (CVD) is a leading cause of death worldwide, and the number of patients with CVD continues to increase despite extensive research and developments in this field. Chronic inflammation is a pivotal pathological component of CVD, and unveiling new proinflammatory factors will help devise novel preventive and therapeutic strategies. The extracellular matrix (ECM) not only provides structural support between cells but also contributes to cellular functions. Secreted protein acidic and rich in cysteine (SPARC) is a collagen-binding matricellular protein that is particularly induced during development and tissue remodeling. A proinflammatory role for SPARC has been demonstrated in various animal models, such as in the lipopolysaccharide-induced footpad model and dextran sodium sulfate-induced colitis model. Recent clinical studies reported a positive correlation between elevated plasma SPARC levels and hypertension, obesity, and the inflammatory marker high-sensitive C-reactive protein. In addition, SPARC gene deletion attenuates the cardiac injury induced by aging, myocardial infarction, and pressure load, suggesting that SPARC has deleterious effects on CVD. This review summarizes the regulatory and proinflammatory mechanisms of SPARC on CVD, chronic kidney disease (CKD), and cerebrovascular disease and discusses the rationale behind measuring SPARC as a biomarker of CVD and the effects of inhibition of SPARC in the prevention and treatment of CVD.

Diallyl trisulfide alleviates dextran sulphate sodium-induced colitis in mice by inhibiting NLRP3 inflammasome activation via ROS/Trx-1 pathway.

Diallyl trisulfide (DATS), a sulphur-containing compound isolated from the medicinal food plant garlic, has been previously reported to attenuate experimental colitis induced by either dextran sodium sulphate (DSS) or 2,4,6-trinitrobenzenesulfonic acid (TNBS) in mice; however, the underlying mechanism remains to be identified. In this study, we deciphered the key mechanism by which DATS alleviates ulcerative colitis (UC). We showed that oral administration of DATS for 10 consecutive days greatly restrained the infiltration of macrophages and the pathological changes in colonic tissues of mice with DSS-induced colitis. DATS treatment notably dampened the content of IL-1β and IL-18 and suppressed NLRP3 inflammasome activation in colon. Mechanistically, DATS effectively diminished the generation of ROS in macrophages. The suppressive effect of DATS on the activation of NLRP3 inflammasome and downregulation of IL-18 and IL-1β levels was blunted by xanthine oxidase. Further studies revealed that DATS inhibited NF-κB pathway activation by suppressing the expression of Trx-1, thereby inhibiting NLRP3 inflammasome activation. Trx-1 overexpression and interference in macrophages promoted and diminished NLRP3 inflammasome activation, respectively. In summary, garlic and its main active ingredient DATS have potentials to prevent and treat UC, and DATS functions by inhibiting NLRP3 inflammasome activation via Trx-1/ROS pathway.

Development of interleukin-27 recombinant Lactococcus lactis and its efficacy in treating psoriasis and colitis in mice

Psoriasis and inflammatory bowel disease (IBD) are chronic immune-mediated diseases that adversely affect patients' quality of life. Interleukin (IL)-27 plays an important role in a variety of infectious diseases, autoimmune disorders, and cancers. However, its therapeutic effects in psoriasis and colitis remain underexplored. In this study, we evaluated the therapeutic potential of recombinant Lactococcus lactis (L. lactis) expressing IL-27 (pIL-27) in imiquimod-induced psoriasis and dextran sodium sulfate-induced colitis mouse models. In the psoriasis mouse model, oral administration of pIL-27 significantly reduced skin scaling, mitigated weight loss, lowered psoriasis area and severity index scores, diminished epidermal hyperplasia and inflammatory cell infiltration, and decreased inflammatory cytokine levels. In the colitis mouse model, oral administration of pIL-27 alleviated weight loss, improved disease activity index scores, prevented colon shortening, ameliorated histopathological changes, and decreased inflammatory cytokine levels. Furthermore, recombinant L. lactis expressing IL-27 could modulate the gut microbiota, increasing the amount of beneficial bacteria and reducing harmful bacteria in the intestine, thereby alleviating the progression of psoriasis and colitis. These results suggest the potential of IL-27 as a therapeutic option for treating psoriasis and IBD.

Osa-miR168a, a Plant miRNA That Survives the Process of In Vivo Food Digestion, Attenuates Dextran Sulfate Sodium-Induced Colitis in Mice by Oral Administration.

Previous studies showed that osa-miR168a, a plant miRNA rich in fruits and vegetables, had cross-kingdom biological effects on immunocytes, silkworms, and rodents. In this study, the effects of miR168a on mouse colitis induced by dextran sulfate sodium (DSS) were investigated. The results showed that miR168a oligomers were resistant during the process of food digestion, ending up with a residual concentration of 67.8 ± 11.2 fM in mouse intestines 4 h after oral gavage. More importantly, direct oral administration of the miRNA to the colitis mice significantly ameliorated the progression of the disease, as evidenced by the reduction in DAI score, histopathological lesions, and proinflammatory cytokines. Repairing intestinal barrier function by promoting the regeneration of TJ proteins and the mucus layer, suppressing oxidative stress and colonic inflammation via modulating Nrf2 and NF-κB signaling pathways, and restoring the imbalanced gut microbiota caused by DSS are proposed mechanisms behind the anticolitis activity of miR168a. This study provided new evidence of the cross-kingdom regulatory effects of dietary miRNAs, suggesting the potential of the plant miRNA for the prevention and treatment of inflammatory bowel diseases.

Acceptable daily intake of aspartame aggravates enteritis pathology and systemic inflammation in colitis mouse model.

In this study, a dextran sodium sulfate-induced ulcerative colitis model in C57BL/6 mice was used to explore the effect of acceptable daily intake (ADI) of aspartame on inflammation in colonic tissues. The effects of aspartame on the inflammatory state of the colon in mice were comprehensively evaluated by comparing the body weight, colon length/colon length index, splenic index, disease activity index (DAI) score, histological activity index (HAI) score, the expression levels of tumor necrosis factor (TNF)-α, interleukin (IL)-1β, IL-6, claudin-3, and occludin, the infiltration characteristics of macrophage and neutrophil and the composition of the gut microbiota in the control group, aspartame group, ulcerative colitis model group, and aspartame + ulcerative colitis group. We demonstrated that, in a mouse model of dextran sulfate-induced ulcerative colitis, ADI of aspartame caused a significant decrease in body weight, colon length/colon length index, DAI scores, and expression levels of the proteins claudin-3 and occludin. Moreover, ADI of aspartame caused an increase in the splenic index, HAI scores, the levels of proinflammatory factors TNF-α, IL-1β, and IL-6 both in intestinal tissue and serum and infiltration of macrophages and neutrophils in colon tissues. These results showed that ADI of aspartame promoted intestinal pathology and systemic inflammation in a mouse model of colitis.

The Therapeutic Effects of Lactic Acid Bacteria Isolated from Spotted Hyena on Dextran Sulfate Sodium-Induced Ulcerative Colitis in Mice.

Inflammatory bowel disease (IBD) is a chronic condition characterized by recurrent episodes and an unclear etiology. Given the limitations of current therapeutic options, which include suboptimal efficacy and significant side effects, there is a pressing need to explore novel treatments. Probiotics derived from diverse species have been identified as a promising approach for managing IBD, owing to their anti-inflammatory properties and their ability to regulate gut flora, among other beneficial effects. In this study, three strains of lactic acid bacteria (LAB) were isolated from the feces of the scavenger spotted hyena (Crocuta crocuta), a scavenging mammal. Based on their capability to survive within and adhere to the gastrointestinal tract, along with their profile of antibiotic resistance, a high-quality strain of Lactobacillus acidophilus (LA) was selected and demonstrated to be safe for mice. Subsequently, the therapeutic efficacy of LA was evaluated using a dextran sulfate sodium (DSS)-induced model of ulcerative colitis in mice. The results indicated that LA restored the disease activity index and improved histopathological lesions in the model group. It also reduced inflammation and oxidative stress and significantly restored the expression of mucins and intestinal tight junction (TJ) proteins (ZO-1, Occludin). Furthermore, LA corrected the DSS-induced disruption of the intestinal flora, leading to a significant decrease in the prevalence of potentially harmful bacterial genera, such as Bacteroides, and an increase in beneficial bacterial genera, including Lactobacillus. In conclusion, Lactobacillus acidophilus LA1, isolated from spotted hyena feces, has potential as a functional supplement for alleviating symptoms of IBD and regulating intestinal flora.

Attenuation by Zhiqiao neohesperidin on dextran sulfate sodium-induced colitis in mice through inhibition of the TLR4/NF-κB pathway

Ulcerative colitis is a chronic inflammatory disease closely associated with immune dysregulation. Zhiqiao (Fructus aurantii), the nearly mature fruit of Citrus aurantium L., is widely used in traditional dietary therapy for intestinal health. Here, we extracted and purified neohesperidin from Zhiqiao and explored its alleviative effects on dextran sulfate sodium-induced colitis and related inflammatory pathways in mice. The results showed that neohesperidin administration significantly ameliorated symptoms of colitis and reduced the accumulation of inflammatory cytokines in mouse tissues and serum. Decreases in the TLR4, MyD88, and NF-κB p65 mRNA expression levels indicated that activity of the TLR4/NF-κB signaling pathway was downregulated. Molecular docking results showed that neohesperidin occupies the lipopolysaccharide-binding pocket of MD-2 and binds to the interacting surface of TLR4/MD-2 and that of the subsequently formed homodimer, thereby disrupting recognition of inflammatory ligands by the TLR4-mediated pathway. Neohesperidin holds promise for the adjunctive treatment of ulcerative colitis.

Staphylea bumalda Alleviates Dextran Sulfate Sodium-Induced Ulcerative Colitis in Mice by Regulating Inflammatory Cytokines, Oxidative Stress, and Maintaining Gut Homeostasis.

Staphylea bumalda is a rare medicine and edible shrub native to the temperate regions of Asia, possessing significant medicinal potential. In this study, the components of S. bumalda tender leaves and buds extract (SBE) were analyzed and identified by HPLC and LC/MS method, and the safety of SBE was evaluated through mouse acute toxicity models. The protective effects of SBE on dextran sulfate sodium (DSS)-induced ulcerative colitis (UC) in mice were investigated in terms of inflammatory factor levels, oxidative stress, and gut microorganisms. Results showed that hyperoside, kaempferol-3-O-rutinoside, isorhoifolin, and rutin were the main components of the extract, and SBE demonstrated good safety in experimental mice. SBE could alleviate weight losing, disease activity index (DAI) raising, and colon shortening in mice. Pathological section results showed that the inflammatory cell infiltration decreased significantly, and the number of goblet cells increased significantly in the SBE group. After SBE treatment, interleukin-6 (IL-6), interleukin-1β (IL-1β), and tumor necrosis factor-α (TNF-α) levels in serum were significantly decreased, and the levels of myeloperoxidase (MPO) and nitric oxide (NO) in colon tissues were significantly decreased. SBE inhibited gut inflammation by increasing Lactobacillus. In summary, SBE played a therapeutic role in UC mice by relieving colon injury, reducing inflammatory factor levels, and maintaining gut flora homeostasis. SBE is expected to become an auxiliary means to participate in the prevention and treatment of UC.

Scutellarein ameliorates dextran sulfate sodium-induced ulcerative colitis by inhibiting colonic epithelial cell proinflammation and barrier disruption.

Scutellarein (Scu) is a natural occurring flavonoid found in multiple traditional Chinese medicines such as Oroxylum indicum (L.) Kurz and Scutellaria baicalensis, with various pharmacological activities including anti-inflammation, anti-oxidation and myocardial protection. Here, we investigated the therapeutic efficacy of Scu on ulcerative colitis (UC) and the underlying mechanism. Efficacy of Scu on UC was evaluated in dextran sulfate sodium (DSS) induced colitis mouse model. Inflammation in colonic tissues was assessed by myeloperoxidase activity assay and RT-qPCR. Barrier proteins expression was examined using immunostaining and Western blot. IL-1β-treated HT-29 cells was used for mechanical investigation. Gavage of Scu significantly decreased the DAI score, improved colon shortening, ameliorated the pathological score in DSS-treated mice with better efficacy than the positive drug, 5-aminosalicylic acid. Scu also inhibited the expression levels of cytokines (Il-1β, Tnf-α, Il-1α, Il-6, and Cxcl1) as well as barrier proteins (E-cadherin, Occludin, and ZO-1) in colon tissues of DSS mice. In intestinal epithelial HT-29 cells, Scu attenuated the IL-1β-downregulated expression levels of E-cadherin, occludin, and ZO-1, while reduced IL-1β-upregulated IL-6 and IL-8 mRNA levels. Moreover, Scu inhibited the phosphorylation and nuclear translocation of NF-κB and suppression of NF-κB phosphorylation abolished IL-1β-disrupted epithelial barrier integrity and IL-1β-upregulated proinflammatory mediators expression in HT-29 cells. These data demonstrate that Scu is an efficacious therapeutic agent to treat UC. Inhibition of inflammatory responses and maintenance of epithelial barrier integrity through NF-κB signaling pathway underlines Scu therapeutic effect on UC.

Phage cocktail inhibits inflammation and protects the integrity of the intestinal barrier in dextran sulfate sodium-induced colitis mice model

Ulcerative colitis (UC) is an inflammatory bowel disease characterized by abdominal pain, diarrhea, and rectal bleeding. This study aims to explore the protective effects of a phage cocktail (108 PFU/mL of Clostridium perfringens phage, 108 PFU/mL of Escherichia coli phage, and 108 PFU/mL of Salmonella phage) on a mouse colitis model induced by dextran sulfate sodium (DSS) and its potential toxic effects on normal mice. The results demonstrate that the phage cocktail significantly alleviates clinical symptoms in mice, reduces colon shortening, weight loss, and colonic pathological damage. Furthermore, the phage cocktail markedly suppresses the inflammatory response and safeguards intestinal barrier integrity in the colonic tissues of the mouse colitis model. Preliminary investigation of the toxic effects of the phage cocktail in mice indicates that continuous administration for 14 days does not yield statistically significant differences in hematological and blood biochemical parameters, and specific pathological changes are absent in histopathological examination results. The aforementioned findings suggest that the phage cocktail exhibits anti-inflammatory and intestinal barrier protective effects in the mouse colitis model, and it does not exert significant toxic side effects on mice.

The reverse transsulfuration pathway affects the colonic microbiota and contributes to colitis in mice

Cystathionine γ-lyase (CTH) is a critical enzyme in the reverse transsulfuration pathway, the major route for the metabolism of sulfur-containing amino acids, notably converting cystathionine to cysteine. We reported that CTH supports gastritis induced by the pathogen Helicobacter pylori. Herein our aim was to investigate the role of CTH in colonic inflammation. First, we found that CTH is induced in the colon mucosa in mice with dextran sulfate sodium-induced colitis. Expression of CTH was completely absent in the colon of Cth–/– mice. We observed that clinical and histological parameters are ameliorated in Cth-deficient mice compared to wild-type animals. However, Cth deletion had no effect on tumorigenesis and the level of dysplasia in mice treated with azoxymethane-DSS, as a reliable model of colitis-associated carcinogenesis. Mechanistically, we determined that the deletion of the gene Slc7a11 encoding for solute carrier family 7 member 11, the transporter of the anionic form of cysteine, does not affect DSS colitis. Lastly, we found that the richness and diversity of the fecal microbiota were significantly increased in Cth–/– mice compared to both WT and Slc7a11–/– mice. In conclusion, our data suggest that the enzyme CTH represents a target for clinical intervention in patients with inflammatory bowel disease, potentially by beneficially reshaping the composition of the gut microbiota.

Solid-State Fermentation of Wheat Bran with Clostridium butyricum: Impact on Microstructure, Nutrient Release, Antioxidant Capacity, and Alleviation of Ulcerative Colitis in Mice.

This study investigated the effects of solid-state fermentation with Clostridium butyricum on the microstructure of wheat bran, the release of dietary fiber and phenolic compounds, and antioxidant capacity. Compared with unfermented wheat bran, insoluble dietary fiber and phytic acid content decreased, whereas soluble dietary fiber and water-extractable arabinoxylan content increased in C. butyricum culture. Because of the increased release of phenolic compounds, such as ferulic acid and apigenin, and organic acids, such as isobutyric acid, the antioxidant capacity of the culture was considerably improved. Furthermore, the culture of C. butyricum treated with dextran sulfate sodium-induced ulcerative colitis in mice enhanced the expression of intestinal mucus and tight-junction proteins, modulating the gut microbiota structure, increasing the levels of short-chain fatty acids in the intestine, and restoring the essential functions of the gut microbiota. These anti-inflammatory effects stemmed from the combined action of various effective components.

ChiA: a major player in the virulence of Crohn’s disease-associated adherent and invasive Escherichia coli (AIEC)

ABSTRACT We investigated the role of ChiA and its associated polymorphisms in the interaction between Crohn’s disease (CD)-associated adherent-invasive Escherichia coli (AIEC) and intestinal mucosa. We observed a higher abundance of chiA among the metagenome of CD patients compared to healthy subjects. In dextran sulfate sodium-induced colitis mice model, AIEC-LF82∆chiA colonization was reduced in ileal, colonic and fecal samples compared to wild-type LF82. The binding of ChiA to recombinant human CHI3L1 or mucus was higher with the pathogenic polymorphism. The strength of ChiA-mucin interaction was 300-fold stronger than ChiA-rhCHI3L1. ChiA was able to degrade mucin to promote its growth and enabled LF82 to get closer to epithelial cells. The pathogenic polymorphism of ChiA had a stronger impact on mucus degradation than on the binding capability of AIEC to adhere to the intestinal epithelium. We observed that ChiA could favor an efficient bacterial invasion of intestinal crypts, and that ChiA, especially its pathogenic polymorphism, gives LF82 an advantage to uptake within Peyer’s patches, macrophages and mesenteric lymph nodes. All together, these data support the role of ChiA in the virulence of AIEC and show that it could be a promising target to reduce AIEC colonization in patients with CD.

Bromodomain-Containing 4 Is a Positive Regulator of Interleukin-34 Production in the Gut.

Experimental evidence suggests that, in the inflamed gut of inflammatory bowel disease (IBD) patients, interleukin-34 (IL-34) triggers detrimental signaling pathways. Factors/mechanisms regulating IL-34 production in IBD remain poorly characterized. Bromodomain-containing 4 (BRD4), a transcriptional and epigenetic regulator, is over-expressed in IBD, and studies in cancer cells suggest that BRD4 might positively control IL-34 expression. This study aimed to assess whether, in IBD, BRD4 regulates IL-34 expression. In IBD, there was an up-regulation of both IL-34 and BRD4 compared to the controls, and the two proteins co-localized in both lamina propria mononuclear cells (LPMCs) and epithelial cells. Flow cytometry analysis of CD45+ LPMCs confirmed that the percentages of IL-34- and BRD4-co-expressing cells were significantly higher in IBD than in the controls and showed that more than 80% of the IL-34-positive CD45-LPMCs expressed BRD4. IL-34 and BRD4 were mainly expressed by T cells and macrophages. IL-34 expression was reduced in IBD LPMCs transfected with BRD4 antisense oligonucleotide and in the colons of mice with dextran sulfate sodium-induced colitis treated with JQ1, a pharmacological inhibitor of BRD4. These data indicate that BRD4 is a positive regulator of IL-34 in IBD, further supporting the pathogenic role of BRD4 in IBD-associated mucosal inflammation.

N-terminomics profiling of naïve and inflamed murine colon reveals proteolytic signatures of legumain.

Legumain is a cysteine protease broadly associated with inflammation. It has been reported to cleave and activate protease-activated receptor 2 to provoke pain associated with oral cancer. Outside of gastric and colon cancer, little has been reported on the roles of legumain within the gastrointestinal tract. Using a legumain-selective activity-based probe, LE28, we report that legumain is activated within colonocytes and macrophages of the murine colon, and that it is upregulated in models of acute experimental colitis. We demonstrated that loss of legumain activity in colonocytes, either through pharmacological inhibition or gene deletion, had no impact on epithelial permeability in vitro. Moreover, legumain inhibition or deletion had no obvious impacts on symptoms or histological features associated with dextran sulfate sodium-induced colitis, suggesting its proteolytic activity is dispensable for colitis initiation. To gain insight into potential functions of legumain within the colon, we performed field asymmetric waveform ion mobility spectrometry-facilitated quantitative proteomics and N-terminomics analyses on naïve and inflamed colon tissue from wild-type and legumain-deficient mice. We identified 16 altered cleavage sites with an asparaginyl endopeptidase signature that may be direct substrates of legumain and a further 16 cleavage sites that may be indirectly mediated by legumain. We also analyzed changes in protein abundance and proteolytic events broadly associated with colitis in the gut, which permitted comparison to recent analyses on mucosal biopsies from patients with inflammatory bowel disease. Collectively, these results shed light on potential functions of legumain and highlight its potential roles in the transition from inflammation to colorectal cancer.

Cordycepin mitigates dextran sulfate sodium-induced colitis through improving gut microbiota composition and modulating Th1/Th2 and Th17/Treg balance

BackgroundImbalances in Th1/Th2 and Th17/Treg immune axes, coupled with disruptions in the gut microbiota (GM), play a pivotal role in the pathogenesis of inflammatory bowel disease (IBD). Cordycepin, a natural anti-inflammatory compound, holds promise in mitigating IBD by rebalancing these immune axes in conjunction with modulating the GM. The aim of this experiment is to investigate the potential of cordycepin in mitigating enteritis and elucidate the underlying mechanisms associated with its ameliorative effects on enteritis. MethodsOn the day of inducing experimental colitis with Dextran Sulfate Sodium (DSS), mice in the DSS + Cordycepin and Cordycepin groups received 50 mg/kg/day Cordycepin via intra-gastric administration (i.g.) for seven consecutive days, respectively. Mice in the DSS and control groups were treated with equal volumes of saline. On day 8, all mice were euthanized under pentobarbital sodium anesthesia. ResultsIn a DSS-induced colitis mouse model, Cordycepin treatment led to a significant reduction in the disease activity index (DAI), splenic weight, and colonic pathological injury while simultaneously improving body weight and colonic length. Furthermore, it positively impacted GM composition, resulting in decreased Th1 and Th17 cells, alongside an increase in Th2 and Treg cells. The contents of the mouse colon were extracted for microbial community analysis. Mouse blood was prepared into a single-cell suspension, and flow cytometry was used to assess the expressio of Treg, Th17, Th1, and Th2 immune cells. ConclusionsThese results underscored the effective intervention of cordycepin in ameliorating DSS-induced colitis by harmonizing the interplay between GM and immune homeostasis.

Dietary Dihydroquercetin Alleviated Colitis via the Short-Chain Fatty Acids/miR-10a-5p/PI3K-Akt Signaling Pathway.

Gut microbiota provides an important insight into clarifying the mechanism of active substances with low bioavailability, but its specific action mechanism varied case by case and remained unclear. Dihydroquercetin (DHQ) is a bioactive flavonoid with low bioavailability, which showed beneficial effects on colitis alleviation and gut microbiota modulation. Herein, we aimed to explore the microbiota-dependent anticolitis mechanism of DHQ in sight of gut microbiota metabolites and their interactions with microRNAs (miRNAs). Dietary supplementation of DHQ alleviated dextran sulfate sodium-induced colitis phenotypes and improved gut microbiota dysbiosis. Fecal microbiota transplantation further revealed that the anticolitis activity of DHQ was mediated by gut microbiota. To clarify how the modulated gut microbiota alleviated colitis in mice, the tandem analyses of the microbiome and targeted metabolome were performed, and altered profiles of metabolite short-chain fatty acids (SCFAs) and bile acids and their producers were observed in DHQ-treated mice. In addition, SCFA treatment showed anticolitis activity compared to that of bile acids, along with the specific inhibition on the phosphoinositide-3-kinase (PI3K)-protein kinase B (Akt) pathway. Subsequently, the colonic miRNA profile of mice receiving SCFA treatment was sequenced, and a differentially expressed miR-10a-5p was identified. Both prediction analysis and dual-luciferase reporter assay indicated that miR-10a-5p directly bind to the 3'-untranslated regions of gene pik3ca, inhibit the PI3K-Akt pathway activation, and lead to colitis alleviation. Together, we proposed that gut microbiota mediated the anticolitis activity of DHQ through the SCFAs/miR-10a-5p/PI3K-Akt axis, and it provided a novel insight into clarifying the microbiota-dependent mechanism via the interaction between metabolites and miRNAs.