Atox1 regulates macrophage polarization in intestinal inflammation via ROS-NLRP3 inflammasome pathway.

BACKGROUND: Inflammation and oxidative stress play an important role in the pathophysiology of inflammatory bowel disease (IBD). This study aimed to explore the effects of copper chaperone Antioxidant-1 (Atox1) on macrophages in a mouse model of intestinal inflammation. METHODS: A mouse model of TNBS-induced colitis was established and verified using the disease activity index. Atox1 conditional knockout mice were applied. The proportion of macrophages in colonic lamina propria mononuclear cells and ROS production were analyzed using flow cytometry. Inflammatory cytokines were measured using ELISA. Expression of macrophage M1/M2 polarization markers, p47phox, NLRP3, and Caspase-1 p20 was measured using quantitative RT-PCR and Western blotting. RESULTS: Atox1 expression was up-regulated in colon tissues of TNBS-induced colitis mice. Macrophages isolated from TNBS-induced colitis mice showed M1 polarization and nuclear translocation of Atox1. Inhibiting copper chaperone activity decreased p47phox, ROS production, and M1 polarization induced by CuCl2 in macrophages. TNBS induced up-regulation of inflammatory cytokines, M1 polarization markers, and p47phox expression in mice, an effect which was preempted by Atox1 knockout. Inflammatory cytokines and expression of M1 polarization markers, p47phox, NLRP3, Caspase-1 p20 were also increased in macrophages isolated from TNBS-induced colitis mice. These changes were alleviated in mice with Atox1 knockout. The effects of Atox1 on macrophage polarization were mediated via the ROS-NLRP3 inflammasome pathway. CONCLUSION: Atox1 plays a pro-inflammatory role, promotes M1 polarization of macrophages, and increases the concentrations of pro-inflammatory cytokines in intestinal tissue by regulating the ROS-NLRP3 inflammasome pathway. Atox1 is a potential therapeutic target in IBD.

[Upregulating KLF11 ameliorates intestinal inflammation in mice with 2, 4, 6-trinitrobenesulfonic acid-induced colitis by inhibiting the JAK2/STAT3 signaling pathway].

OBJECTIVE: To investigate the expression level of Kruppel-like transcription factor family member KLF11 in intestinal mucosal tissues of Crohn's disease (CD) and its regulatory effect on intestinal inflammation in CD-like colitis. METHODS: We examined KLF11 expression levels in diseased and normal colon mucosal tissues from 12 CD patients and 12 patients with colorectal cancer using immunofluorescence staining. KLF11 expression was also detected in the colon mucosal tissues of a mouse model of 2, 4, 6-trinitrobenesulfonic acid (TNBS)-induced colitis. A recombinant adenoviral vector was used to upregulate KLF11 expression in the mouse models and the changes in intestinal inflammation was observed. A Caco-2 cell model with stable KLF11 overexpression was constructed by lentiviral infection. The effect of KLF11 overexpression on expressions of JAK2/STAT3 signaling pathway proteins was investigated using immunoblotting in both the mouse and cell models. The mouse models were treated with coumermycin A1, a JAK2/STAT3 signaling pathway agonist, and the changes in intestinal inflammatory responses were observed. RESULTS: The expression level of KLF11 was significantly lowered in both the clinical specimens of diseased colon mucosal tissues and the colon tissues of mice with TNBS-induced colitis (P < 0.05). Adenovirus-mediated upregulation of KLF11 significantly improved intestinal inflammation and reduced the expression levels of inflammatory factors in the intestinal mucosa of the colitis mouse models (P < 0.05). Overexpression of KLF11 significantly inhibited the expression levels of p-JAK2 and p-STAT3 in intestinal mucosal tissues of the mouse models and in Caco-2 cells (P < 0.05). Treatment with coumermycin A1 obviously inhibited the effect of KLF11 upregulation for improving colitis and significantly increased the expression levels of inflammatory factors in the intestinal mucosa of the mouse models (P < 0.05). CONCLUSION: KLF11 is downregulated in the intestinal mucosa in CD, and upregulation of KLF11 can improve intestinal inflammation and reduce the production of inflammatory factors probably by inhibiting the JAK2/STAT3 signaling pathway.

Casearia sylvestris var. lingua (Càmbess.) Eichler leaves aqueous extract improves colon inflammation through mucogenic, antioxidant and anti-inflammatory actions in TNBS- induced IBD rats.

ETHNOPHARMACOLOGICAL RELEVANCE: Casearia sylvestris var. lingua (Cambess.) Eichler, a member of the Salicaceae family, holds a prominent place in traditional medicine across various cultures due to its versatile therapeutic properties. Historically, indigenous communities have utilized different parts of the plant, including leaves, bark, and roots, to address a wide array of health conditions. Traditional uses of C. sylvestris var. lingua encompasses the treatment of gastrointestinal disorders, respiratory infections, wound healing, inflammation, and stomach ulcers. Pharmacological studies have demonstrated the plant's antimicrobial, anti-inflammatory, antioxidant, analgesic, gastroprotective, and immunomodulatory effects. This signifies the first scientific validation report for C. sylvestris var. lingua regarding its effectiveness against ulcerative colitis. The report aims to affirm the traditional use of this plant through pre-clinical experiments. AIM OF THE RESEARCH: This work uses an aqueous extract from C. sylvestris var. lingua leaves (AECs) to evaluate the acute anti-ulcerative colitis efficacy in rat and HT-29 (human colorectal cancer cell line) models. METHODS: To determine the secondary metabolites of AECs, liquid chromatography with a diode array detector (LC-DAD) study was carried out. 2,4,6-trinitrobenzenesulfonic acid (TNBS, 30 mg/0.25 mL EtOH 30% v/v) was used as an enema to cause acute colitis. Three days were spent giving the C. sylvestris var. lingua extract orally by gavage at dosages of 3, 30, and 300 mg/kg. The same route was used to deliver distilled water to the vehicle and naïve groups. After the animals were sacrificed on the fourth day, intestinal tissues were taken for histological examination and evaluation of biochemical tests such as those measuring superoxide dismutase (SOD), reduced glutathione (GSH), catalase (CAT), malondialdehyde (MDA), nitrite/nitrate, myeloperoxidase (MPO) activity. Additionally, interleukin 1 beta (IL-1ß), tumor necrosis factor alpha (TNF-α), and interleukin 10 (IL-10), were conducted on the intestinal tissues. Additionally, an MTT assay was used to evaluate the effect of AECs on the viability of HT-29 cells. Additionally, a molecular docking study was carried out to compare some potential target proteins with identified chemicals found in AECs. RESULTS: LC-DAD analysis identified five compounds (caffeic acid, ellagic acid, ferulic acid, gallic acid, and quercetin) in AECs. Pre-administration of AECs (3; 30; 300 mg/kg) and mesalazine (500 mg/kg) reduced macroscopic scores (55%, 47%, 45%, and 52%, p < 0.001) and ulcerated areas (70.3%, 70.5%, 57%, and 56%, p < 0.001), respectively. It also increased SOD, GSH, and CAT activities (p < 0.01), while decreasing MDA (p < 0.001), nitrite/nitrate (p < 0.05), and MPO (p < 0.001) activities compared to the colitis group. Concerning inflammatory markers, significant modulations were observed: AECs (3, 30, and 300 mg/kg) lowered levels of IL-1ß and TNF-α (p < 0.001) and increased IL-10 levels (p < 0.001) compared to the colitis groups. The viability of HT-29 cells was suppressed by AECs with an IC50 of 195.90 ± 0.01 µg/mL (48 h). During the molecular docking analysis, quercetin, gallic acid, ferulic acid, caffeic acid, and ellagic acid demonstrated consistent binding affinities, forming stable interactions with the 3w3l (TLR8) and the 3ds6 (MAPK14) complexes. CONCLUSION: These results imply that the intestinal mucogenic, anti-inflammatory, and antioxidant properties of the C. sylvestris var. lingua leaf extract may be involved in its therapeutic actions for ulcerative colitis. The results of the in silico study point to the possibility of quercetin and ellagic acid interacting with P38 and TLR8, respectively, in a beneficial way.

Potential mitigation of titanium dioxide nanoparticles against 2,4,6-trinitrobenzene sulfonic acid (TNBS)-induced colitis through inhibiting the canonical NF-κB pathway.

Titanium dioxide nanoparticles (TiO2 NPs) have been widely employed in various industry fields, which makes consumers concerned about their health impact. Our previous work displayed that TiO2 NPs participated in the mitigation of TNBS-induced colitis, but the mechanism is still unknown. This work aimed to explore the role of oxidative stress and NF-κB pathway in the effect of TiO2 NPs on TNBS-induced colitis. The results showed that TiO2 NPs administration reduced the DAI score of colitis mice after TNBS enema. TiO2 NPs did not alter oxidative stress status (GSH/GSSG), but repaired the gut dysbacteriosis and inhibited the canonical NF-κB pathway activation in TNBS-induced colitis mice, manifested as a decrease in pathogenic bacteria and an increase in beneficial bacteria, as well as down-regulation of toll-like receptors (TLRs), IKKα, IKKß, p65 and pro-inflammatory cytokines (IL-1ß, IL-6, TNF-α and IFN-γ) in mRNA level, and the increased transcription of anti-inflammatory cytokines (IL-10, TGF-ß, and IL-12), along with the declined protein level of TNF-α in TiO2 NPs treated colitis mice. The present study suggested that oral TiO2 NPs administration inhibited the canonical NF-κB pathway activation by repairing gut dysbacteriosis, which made a predominant role in alleviating colitis. These findings provided a new perspective for exploring the safety of TiO2 NPs.

Magnolin inhibits intestinal epithelial cell apoptosis alleviating Crohn's disease-like colitis by suppressing the PI3K/AKT signalling pathway.

BACKGROUND AND AIMS: Previous reports have shown that preventing excessive intestinal epithelial cell (IEC) apoptosis is a crucial approach for protecting the intestinal barrier in patients with Crohn's disease (CD). Magnolin (MGL) has various biological activities, including antiapoptotic activities, but its role in CD has largely not been determined. This study investigated how MGL impacts CD-like colitis and the underlying mechanism involved. METHODS: Mice were treated with TNBS to establish a disease model, and these mice were used to assess the therapeutic effects of MGL on CD-like colitis. TNF-α-treated colon organoids were used to evaluate the impact of MGL on intestinal barrier function and IEC apoptosis. Enrichment analysis was performed to examine the potential pathways through which MGL inhibits IEC apoptosis. Finally, rescue experiments showed the mechanism by which MGL suppresses IEC apoptosis. RESULTS: The animal experiments demonstrated that MGL treatment alleviated the weight loss, colon shortening, elevated disease activity index (DAI) scores, increased colitis histological scores and upregulated inflammatory factor expression that were observed in model mice. MGL ameliorated intestinal barrier dysfunction and the loss of tight junction (TJ) proteins (ZO-1 and Claudin-1) by inhibiting IEC apoptosis in both TNBS-treated mice and TNF-α-treated colon organoids. MGL inhibited the PI3K/AKT signalling pathway, thus safeguarding the intestinal barrier and alleviating CD-like colitis in vivo and in vitro. CONCLUSIONS: MGL improves the intestinal barrier integrity and prevents CD-like colitis by inhibiting IEC apoptosis. The potential mechanism of its anti-apoptotic impact on IECs could be associated with the PI3K/AKT pathway, presenting novel approaches and avenues for the clinical management of CD.

Chitin-glucan improves important pathophysiological features of irritable bowel syndrome.

BACKGROUND: Irritable bowel syndrome (IBS) is one of the most frequent and debilitating conditions leading to gastroenterological referrals. However, recommended treatments remain limited, yielding only limited therapeutic gains. Chitin-glucan (CG) is a novel dietary prebiotic classically used in humans at a dosage of 1.5-3.0 g/d and is considered a safe food ingredient by the European Food Safety Authority. To provide an alternative approach to managing patients with IBS, we performed preclinical molecular, cellular, and animal studies to evaluate the role of chitin-glucan in the main pathophysiological mechanisms involved in IBS. AIM: To evaluate the roles of CG in visceral analgesia, intestinal inflammation, barrier function, and to develop computational molecular models. METHODS: Visceral pain was recorded through colorectal distension (CRD) in a model of long-lasting colon hypersensitivity induced by an intra-rectal administration of TNBS [15 milligrams (mg)/kilogram (kg)] in 33 Sprague-Dawley rats. Intracolonic pressure was regularly assessed during the 9 wk-experiment (weeks 0, 3, 5, and 7) in animals receiving CG (n = 14) at a human equivalent dose (HED) of 1.5 g/d or 3.0 g/d and compared to negative control (tap water, n = 11) and positive control (phloroglucinol at 1.5 g/d HED, n = 8) groups. The anti-inflammatory effect of CG was evaluated using clinical and histological scores in 30 C57bl6 male mice with colitis induced by dextran sodium sulfate (DSS) administered in their drinking water during 14 d. HT-29 cells under basal conditions and after stimulation with lipopolysaccharide (LPS) were treated with CG to evaluate changes in pathways related to analgesia (µ-opioid receptor (MOR), cannabinoid receptor 2 (CB2), peroxisome proliferator-activated receptor alpha, inflammation [interleukin (IL)-10, IL-1b, and IL-8] and barrier function [mucin 2-5AC, claudin-2, zonula occludens (ZO)-1, ZO-2] using the real-time PCR method. Molecular modelling of CG, LPS, lipoteichoic acid (LTA), and phospholipomannan (PLM) was developed, and the ability of CG to chelate microbial pathogenic lipids was evaluated by docking and molecular dynamics simulations. Data were expressed as the mean ± SEM. RESULTS: Daily CG orally-administered to rats or mice was well tolerated without including diarrhea, visceral hypersensitivity, or inflammation, as evaluated at histological and molecular levels. In a model of CRD, CG at a dosage of 3 g/d HED significantly decreased visceral pain perception by 14% after 2 wk of administration (P < 0.01) and reduced inflammation intensity by 50%, resulting in complete regeneration of the colonic mucosa in mice with DSS-induced colitis. To better reproduce the characteristics of visceral pain in patients with IBS, we then measured the therapeutic impact of CG in rats with TNBS-induced inflammation to long-lasting visceral hypersensitivity. CG at a dosage of 1.5 g/d HED decreased visceral pain perception by 20% five weeks after colitis induction (P < 0.01). When the CG dosage was increased to 3.0 g/d HED, this analgesic effect surpassed that of the spasmolytic agent phloroglucinol, manifesting more rapidly within 3 wk and leading to a 50% inhibition of pain perception (P < 0.0001). The underlying molecular mechanisms contributing to these analgesic and anti-inflammatory effects of CG involved, at least in part, a significant induction of MOR, CB2 receptor, and IL-10, as well as a significant decrease in pro-inflammatory cytokines IL-1b and IL-8. CG also significantly upregulated barrier-related genes including muc5AC, claudin-2, and ZO-2. Molecular modelling of CG revealed a new property of the molecule as a chelator of microbial pathogenic lipids, sequestering gram-negative LPS and gram-positive LTA bacterial toxins, as well as PLM in fungi at the lowesr energy conformations. CONCLUSION: CG decreased visceral perception and intestinal inflammation through master gene regulation and direct binding of microbial products, suggesting that CG may constitute a new therapeutic strategy for patients with IBS or IBS-like symptoms.

Anti-inflammatory and protective effects of Aripiprazole on TNBS-Induced colitis and associated depression in rats: Role of kynurenine pathway.

BACKGROUND: The prevalence of depression is higher in patients with inflammatory bowel disease (IBD) than in the general population. Inflammatory cytokines and the kynurenine pathway (KP) play important roles in IBD and associated depression. Aripiprazole (ARP), an atypical antipsychotic, shows various anti-inflammatory properties and may be useful in treating major depressive disorder. This study aimed to evaluate the protective effects of ARP on TNBS-induced colitis and subsequent depression in rats, highlighting the role of the KP. MATERIAL AND METHODS: Fifty-six male Wistar rats were used, and all groups except for the normal and sham groups received a single dose of intra-rectal TNBS. Three different doses of ARP and dexamethasone were injected intraperitoneally for two weeks in treatment groups. On the 15th day, behavioral tests were performed to evaluate depressive-like behaviors. Colon ulcer index and histological changes were assessed. The tissue levels of inflammatory cytokines, KP markers, lipopolysaccharide (LPS), nuclear factor-kappa-B (NF-κB), and zonula occludens (ZO-1) were evaluated in the colon and hippocampus. RESULTS: TNBS effectively induced intestinal damages and subsequent depressive-like symptoms in rats. TNBS treatment significantly elevated the intestinal content of inflammatory cytokines and NF-κB expression, dysregulated the KP markers balance in both colon and hippocampus tissues, and increased the serum levels of LPS. However, treatment with ARP for 14 days successfully reversed these alterations, particularly at higher doses. CONCLUSION: ARP could alleviate IBD-induced colon damage and associated depressive-like behaviors mainly via suppressing inflammatory cytokines activity, serum LPS concentration, and affecting the NF-κB/kynurenine pathway.

Complanatuside A ameliorates 2,4,6-trinitrobenzene sulfonic acid-induced colitis in mice by regulating the Th17/Treg balance via the JAK2/STAT3 signaling pathway.

Immunity imbalance of T helper 17 (Th17)/regulatory T (Treg) cells is involved in the pathogenesis of Crohn's disease (CD). Complanatuside A (CA), a flavonol glycoside, exerts anti-inflammatory activities and our study aimed to identify its effect on TNBS-induced colitis and the possible mechanisms. We found that CA alleviated the symptoms of colitis in TNBS mice, as demonstrated by prevented weight loss and colon length shortening, as well as decreased disease activity index scores, inflammatory scores, and levels of proinflammatory factors. Flow cytometry analysis showed that CA markedly reduced the percentage of Th17 cells while increasing the percentage of Treg cells in TNBS mice. Under Th17 cell polarizing conditions, CA inhibited the differentiation of Th17 cells while the Treg cell differentiation was elevated under Treg cell polarizing conditions. Furthermore, it was observed that JAK2 interacted with CA through six hydrogen bonds via molecular docking. The phosphorylation of JAK2/STAT3 was reduced by CA, which might be correlated with the protective effect of CA on colitis. In conclusion, CA reduced the imbalance of Th17/Treg cells by inhibiting the JAK2/STAT3 signaling pathway in TNBS-induced colitis, which may provide novel strategies for CD treatment.

hUC-MSCs therapy for Crohn's disease: efficacy in TNBS-induced colitis in rats and pilot clinical study.

BACKGROUND: The use of mesenchymal stem cells (MSCs) has recently emerged as a promising new therapeutic strategy for many diseases including perianal fistulizing Crohn's disease (CD). Whether hUC-MSCs can promote the healing of luminal ulcer in CD has not been studied so far. METHODS: The model of TNBS-induced colitis in rats was used to confirm the efficacy of hUC-MSCs in the treatment of CD. Then, seventeen CD patients refractory to or unsuitable for currently available therapies were enrolled and received once submucosal local injection through colonoscopy combined with once intravenous drip on the next day. All patients received a 24-week follow-up. Clinical and laboratory assessments were monitored at baseline, week 4, 8, 12, and 24. Endoscopic evaluations were conducted at baseline and week 12. Mucosal specimens were obtained at the margin of lesions by endoscopy biopsies and used for RNA sequencing. Two hUC-MSCs co-culture systems were established in vitro, one with the mucosa specimens and the other with M1 macrophages induced from THP1. The expressions of genes representing inflammation (TNFα, IL-6, and IL-1ß) and intestinal barrier function (ZO1, CLAUDIN1, and CDH1) were tested by RT-PCR. FINDINGS: hUC-MSCs treatment increased body weight and decreased disease activity index (DAI), colon macroscopic damage index (CMDI), and histopathological score (HPS) of rats with TNBS-induced colitis. The results of the clinical study also showed that this mode of hUC-MSCs application was associated with regression of intestinal ulceration. Eight patients (47%) got endoscopic responses (SES-CD improvement of ≥50% from baseline) and three patients (17.65%) got mucosal healing (SES-CD is zero), with a parallel improvement of clinical and laboratory parameters without serious adverse events. RNA sequencing showed hUC-MSCs therapy was associated with an upregulation of transcripts linked to intestinal epithelial barrier integrity and a downregulation of inflammatory signaling pathways in the intestinal mucosa, especially the TNF signaling pathway, IL-17 signaling pathway, and TLR signaling pathway. RNA expression of intestinal epithelial tight junction protein (ZO1, CLAUDIN1, and CDH1), and the RNA expression of major intestinal inflammatory factors in CD (IL-1ß, IL-6, and TNFα, p < 0.001 for all) were improved significantly. Moreover, hUC-MSCs could attenuate the polarization of M1 macrophage induced from THP1, thereby decreasing the mRNA expression of IL-1ß, IL-6, and TNFα significantly (p < 0.05 for all). TSG-6 expression was evaluated in hUC-MSCs culture supernatant after treatment with TNFα, IFNγ, and LPS for 48 h. And hUC-MSCs could inhibit the phosphorylation of JAK/STAT1 in the intestinal mucosa of CD patients. INTERPRETATION: hUC-MSCs transplantation alleviated TNBS-induced colitis in rats. In this pilot clinical study, preliminary data suggested that this approach to administering hUC-MSCs might have potential for clinical efficacy and manageable safety in treating refractory CD, potentially providing hope for better outcomes. No serious adverse events were observed. FUNDING: This work was funded by General Program of National Natural Science Foundation of China (Grant No. 82270639), the Scientific research project of Shanghai Municipal Health Committee (Grant No. 202240001), Specialty Feature Construction Project of Shanghai Pudong New Area Health Commission (Grant No. PWZzb2022-05), Shanghai East Hospital Youth Research and Cultivation Foundation program (Grant No. DFPY2022015), Peak Disciplines (Type IV) of Institutions of Higher Learning in Shanghai, Technology Development Project of Pudong Science, Technology and Economic Commission of Shanghai (Grant No. PKJ2021-Y08), Key Disciplines Group Construction Project of Shanghai Pudong New Area Health Commission (Grant No. PWZxq2022-06), Medical discipline Construction Project of Pudong Health Committee of Shanghai (Grant No. PWYgf2021-02) and National Natural Science Foundation of China (Grant No. 82300604).

Sclareol protected against intestinal barrier dysfunction ameliorating Crohn's disease-like colitis via Nrf2/NF-B/MLCK signalling.

BACKGROUND: Inflammation-induced intestinal barrier dysfunction is not only a pathological feature of Crohn's disease (CD) but also an important therapeutic target. Sclareol (SCL) is a nontoxic natural plant compound with anti-inflammatory effect, but its role in CD has not been established. METHODS: In vivo studies of mice with TNBS-induced colitis were carried out to evaluate the effects of SCL on CD-like colitis and intestinal barrier function. In vitro, a TNF-α-induced colonic organoid model was established to test the direct effect of SCL on inflammation-induced intestinal barrier injure and inflammatory response. The Nrf2/NF-κB/MLCK signalling was analysed to explore the mechanism of SCL. RESULTS: In vivo, SCL largely alleviated the colitis in TNBS mice, as evidenced by improvements in the weight loss, colitis symptoms, endoscopic score, macroscopic histological score, and histological inflammation score. Moreover, SCL significantly improved intestinal barrier dysfunction, manifested as reduced intestinal permeability and decreased intestinal bacterial translocation in TNBS mice. Importantly, SCL antagonised the intestinal mucosal inflammation while protecting tight junctions in TNBS mice. In vitro, SCL largely depressed pro-inflammatory cytokines levels and improved intestinal epithelial permeability in a TNF-α-induced colonic organoid model. In the context of CD, the protective effects of SCL against inflammation and intestinal barrier damage are at least partially results from the Nrf2 signalling activation and the NF-κB/MLCK signalling inhibition. CONCLUSIONS: SCL improved intestinal barrier dysfunction and alleviated CD-like colitis, possibly through modulation of Nrf2/NF-κB/MLCK signalling. In view of SCL's safety profile, there is hope that it will be useful in the clinic.

Gut bacteria exacerbates TNBS-induced colitis and kidney injury through oxidative stress.

Gut microbiota has been implicated in the initiation and progression of various diseases; however, the underlying mechanisms remain elusive and effective therapeutic strategies are scarce. In this study, we investigated the role and mechanisms of gut microbiota in TNBS-induced colitis and its associated kidney injury while evaluating the potential of dietary protein as a therapeutic intervention. The intrarectal administration of TNBS induced colitis in mice, concurrently with kidney damage. Interestingly, this effect was absent when TNBS was administered intraperitoneally, indicating a potential role of gut microbiota. Depletion of gut bacteria with antibiotics significantly attenuated the severity of TNBS-induced inflammation, oxidative damage, and tissue injury in the colon and kidneys. Mechanistic investigations using cultured colon epithelial cells and bone-marrow macrophages unveiled that TNBS induced cell oxidation, inflammation and injury, which was amplified by the bacterial component LPS and mitigated by thiol antioxidants. Importantly, in vivo administration of thiol-rich whey protein entirely prevented TNBS-induced colonic and kidney injury. Our findings suggest that gut bacteria significantly contribute to the initiation and progression of colitis and associated kidney injury, potentially through mechanisms involving LPS-induced exaggeration of oxidative cellular damage. Furthermore, our research highlights the potential of dietary thiol antioxidants as preventive and therapeutic interventions.

Protective effect of sucrose esters from cape gooseberry (Physalis peruviana L.) in TNBS-induced colitis.

Phytotherapy is an attractive strategy to treat inflammatory bowel disease (IBD) that could be especially useful in developing countries. We previously demonstrated the intestinal anti-inflammatory effect of the total ethereal extract from the Physalis peruviana (Cape gooseberry) calyces in TNBS-induced colitis. This work investigates the therapeutic potential of Peruviose A and B, two sucrose esters that constitute the major metabolites of its calyces. The effect of the Peruvioses A and B mixture on TNBS-induced colitis was studied after 3 (preventive) and 15-days (therapy set-up) of colitis induction in rats. Colonic inflammation was assessed by measuring macroscopic/histologic damage, MPO activity, and biochemical changes. Additionally, LPS-stimulated RAW 264.7 macrophages were treated with test compounds to determine the effect on cytokine imbalance in these cells. Peruvioses mixture ameliorated TNBS-induced colitis in acute (preventive) or established (therapeutic) settings. Although 3-day treatment with compounds did not produce a potent effect, it was sufficient to significantly reduce the extent/severity of tissue damage and the microscopic disturbances. Beneficial effects in the therapy set-up were substantially higher and involved the inhibition of pro-inflammatory enzymes (iNOS, COX-2), cytokines (TNF-α, IL-1ß, and IL-6), as well as epithelial regeneration with restoration of goblet cells numbers and expression of MUC-2 and TFF-3. Consistently, LPS-induced RAW 264.7 cells produced less NO, PGE2, TNF-α, IL-6, and MCP-1. These effects might be related to the inhibition of the NF-κB signaling pathway. Our results suggest that sucrose esters from P. peruviana calyces, non-edible waste from fruit production, might be useful as an alternative IBD treatment.

Quercetin Attenuates Endoplasmic Reticulum Stress and Apoptosis in TNBS-Induced Colitis by Inhibiting the Glucose Regulatory Protein 78 Activation.

Background: The inflammatory bowel diseases (IBD) are significantly influenced by apoptosis and endoplasmic reticulum (ER) stress. Aims: To investigate the effects of quercetin on ER stress-mediated apoptosis in a trinitrobenzene sulfonic acid (TNBS) induced experimental IBD model. Study Design: In vivo animal experimental study. Methods: To demonstrate the effect of quercetin in an experimental colitis model, Control, TNBS, and TNBS+quercetin groups were created with 24 Wistar Albino rats. Colitis was induced by intrarectal administration of 25 mg TNBS. In the TNBS+quercetin group, intragastrically 100 mg/kg quercetin was given for 7 days, immediately after colitis induction. In the TNBS-induced experimental IBD model, we evaluated the effects of quercetin on colonic epithelial cell apoptosis, oxidative stress, ER stress, the mitogen-activated protein kinase c-Jun N-terminal kinase, and the nuclear factor kappa B immunoreactivities, the levels of myeloperoxidase and tumor necrosis factor-α, the disease activity index with colonic histopathologic changes. Results: TNBS administration induced an elevated level of disease activity and oxidative stress indices, inflammation markers, and an increase in the immunoreactivities of nuclear factor kappa B and the mitogen-activated protein kinase c-Jun N-terminal kinase in the colon of the colitis group. Glucose regulatory protein 78, caspase-12 immunoreactivities, and epithelial cell apoptosis also were shown in the colon. However, quercetin improved TNBS-induced histopathological alterations, apoptosis, inflammation, oxidative stress, and ER stress. Conclusion: This study suggests that quercetin has a regulatory effect on ER stress-mediated apoptosis, and thus may be beneficial in treating IBD.

Phyllanthus emblica L. polysaccharides ameliorate colitis via microbiota modulation and dual inhibition of the RAGE/NF-κB and MAPKs signaling pathways in rats.

Pharmacological treatments for colitis have limited efficacy and side effects. Plant polysaccharides improve colitis by modulating the gut microbiota. However, the specific benefits of Phyllanthus emblica L. polysaccharides (PEPs) in colitis remain unclear. Therefore, this study aimed to assess the physical characteristics and health advantages of PEP in rats subjected to 2,4,6-trinitrobenzene sulfonic acid (TNBS) treatment. The results showed that PEP (1.226 × 103 kDa) was an α-acidic pyran heteropolysaccharide rich in galactose and galacturonic acid. Prefeeding rats with PEP significantly decreased the levels of NO, MDA, proinflammatory cytokines (IL-6, IL-1ß, TNF-α), apoptosis, and the activities of mucinase and ß-glucuronidase. These changes were accompanied by increases in the levels of anti-inflammatory cytokines (IL-4, IL-10) and antioxidant enzymes (SOD, catalase, GPx) in colitis rats. Mechanistically, PEP suppressed the abundance of inflammatory-related bacteria (Bacteroides, Intestinimonas, and Parabacteroides) while promoting the growth of short-chain fatty acid (SCFA)-producing bacteria (Romboutsia, Clostridium_sensu_stricto_1, and Lactobacillus), along with an increase in SCFA secretion. SCFAs may engage with the GPR43 receptor and inhibit downstream HDAC3, consequently downregulating the activation of the RAGE/NF-κB and MAPK pathways. In conclusion, PEP demonstrated preventive effects through its antioxidant, anti-inflammatory, and microbiota modulation properties, thereby ameliorating TNBS-induced colitis in rats.

Transient receptor potential melastatin 2 is involved in trinitrobenzene sulfonic acid-induced acute and chronic colitis-associated fibrosis progression in mice.

Crohn's disease, a chronic and recurrent gastrointestinal disease, frequently causes intestinal fibrosis. Transient receptor potential melastatin 2 (TRPM2), a non-selective cation channel, is activated by reactive oxygen species. This study investigated the role of TRPM2 in acute colitis and chronic colitis-associated fibrosis progression. Acute colitis and chronic colitis-associated fibrosis were induced in TRPM2-deficient (TRPM2KO) and wild-type (WT) mice through single and repeated intrarectal injections of 2,4,6-trinitrobenzene sulfonic acid (TNBS). Bone marrow-derived macrophages (BMDMs) from WT and TRPM2KO mice were stimulated using H2O2. In WT mice, a single TNBS injection induced acute colitis with upregulated inflammatory cytokines/chemokines and Th1/Th17-related cytokines, while repeated TNBS injections induced chronic colitis-associated fibrosis with upregulation of fibrogenic factors and Th2-related cytokines. Acute colitis and chronic colitis-associated fibrosis with cytokines/chemokine upregulation and fibrogenic factors were considerably suppressed in TRPM2KO mice. Treating BMDMs with H2O2 increased cytokine/chemokine expression and JNK, ERK, and p38 phosphorylation; however, these responses were significantly less in TRPM2KO than in WT mice. These findings suggest that TRPM2 contributes to acute colitis progression via Th1/Th17-mediated immune responses. Furthermore, TRPM2 may be directly involved in colitis-associated fibrosis induction, likely due to the regulation of Th2/TGF-ß1-mediated fibrogenesis in addition to a consequence of acute colitis progression.

Shaoyao decoction alleviates TNBS-induced ulcerative colitis by decreasing inflammation and balancing the homeostasis of Th17/Treg cells.

BACKGROUND: Ulcerative colitis (UC) is a persistent and non-specific inflammatory condition that mainly affects the bowels and has challenging treatment. UC has a growing incidence and significantly affects the well-being of patients. Many medications used to treat UC can disrupt the metabolism and immune system homeostasis, frequently leading to significant adverse effects. Hence, exploring alternative therapies, such as traditional Chinese medicine and probiotics, has recently emerged as a primary research hotspot owing to their safety. Although the therapeutic mechanism of Shaoyao decoction has not been clarified, it has demonstrated a beneficial clinical effect on UC. AIM: This study aimed to assess the effect of Shaoyao decoction on a rat model of UC and investigate its underlying mechanisms. METHODS: The rat model of UC was induced by 2,4,6-trinitrobenzenesulfonic acid (TNBS). The extent of damage to the intestines was assessed using the disease activity index (DAI), colonic mucosa damage index (CMDI), and histological scores. Immunohistochemistry was employed to detect the tissue levels of interleukin (IL)-17, transforming growth factor (TGF)-ß1, and IL-10. Additionally, the proportion of Th17 and Treg cells was detected using flow cytometry. In colon tissue, the levels of forkhead box (Fox)p3, RAR-related orphan receptor (ROR)γt, IL-6, p-STAT3, and STAT3 proteins were quantified by Western blotting. RESULTS: Treatment with Shaoyao decoction enhanced the overall health of rats and reduced colonic damage. Additionally, Shaoyao decoction significantly alleviated the severity of DAI, CMDI, and HS. The proportion of Th17 cells was reduced, and the proportion of Treg cells was increased by Shaoyao decoction. The expression of IL-17 and RORγt was suppressed by Shaoyao decoction, while the expression of IL-10, TGF-ß1, and Foxp3 was increased. The expression of IL-6, p-STAT3, and STAT3 was decreased by Shaoyao decoction. CONCLUSION: The Shaoyao decoction alleviates the symptoms of TNBS-induced UC by decreasing inflammation and mitigating intestinal damage while preserving the balance between Th17 and Treg. Shaoyao decoction modulates the IL-6/STAT3 axis, thereby regulating the balance between Th17 and Treg cells.

Human umbilical cord mesenchymal stem cells alleviated TNBS-induced colitis in mice by restoring the balance of intestinal microbes and immunoregulation.

AIMS: Human umbilical cord mesenchymal stem cells (HUMSCs) have been documented to be effective for several immune disorders including inflammatory bowel diseases (IBD). However, it remains unclear how HUMSCs function in regulating immune responses and intestinal flora in the trinitrobenzene sulfonic acid (TNBS)-induced IBD model. MATERIALS AND METHODS: We assessed the regulatory effects of HUMSCs on the gut microbiota, T lymphocyte subpopulations and related immune cytokines in the TNBS-induced IBD model. The mice were divided into the normal, TNBS, and HUMSC-treated groups. The effect of HUMSCs was evaluated by Hematoxylin and Eosin (H&E) staining, fluorescence-activated cell sorting (FACS), and enzyme-linked immunosorbent assay (ELISA) analyses. Metagenomics Illumina sequencing was conducted for fecal samples. KEY FINDINGS: We demonstrated that the disease symptoms and pathological changes in the colon tissues of TNBS-induced colitis mice were dramatically ameliorated by HUMSCs, which improved the gut microbiota and rebalanced the immune system, increasing the abundance of healthy bacteria (such as Lactobacillus murinus and Lactobacillus johnsonii), the Firmicutes/Bacteroidetes ratio, and the proportion of Tregs; the Th1/Th17 ratio was decreased. Consistently, the expression levels of IFN-γ and IL-17 were significantly decreased, and transforming growth factor-ß1 (TGF-ß1) levels were significantly increased in the plasma of colitis mice HUMSC injection. SIGNIFICANCE: Our experiment revealed that HUMSCs mitigate acute colitis by regulating the rebalance of Th1/Th17/Treg cells and related cytokines and remodeling the gut microbiota, providing potential future therapeutic targets in IBD.

Dynamic alterations in metabolomics and transcriptomics associated with intestinal fibrosis in a 2,4,6-trinitrobenzene sulfonic acid-induced murine model.

BACKGROUND & AIMS: Intestinal fibrosis is a common and severe complication of inflammatory bowel disease without clear pathogenesis. Abnormal expression of host genes and metabolic perturbations might associate with the onset of intestinal fibrosis. In this study, we aimed to investigate the relationship between the development of intestinal fibrosis and the dynamic alterations in both fecal metabolites and host gene expression. METHODS: We induced intestinal fibrosis in a murine model using 2,4,6-trinitrobenzene sulfonic acid (TNBS). TNBS-treated or control mice were sacrificed after 4 and 6 weeks of intervention; alterations in colonic genes and fecal metabolites were determined by transcriptomics and metabolomics, respectively. Differential, tendency, enrichment, and correlation analyses were performed to assess the relationship between host genes and fecal metabolites. RESULTS: RNA-sequencing analysis revealed that 679 differential genes with enduring changes were mainly enriched in immune response-related signaling pathways and metabolism-related biological processes. Among them, 15 lipid metabolism-related genes were closely related to the development of intestinal fibrosis. Moreover, the fecal metabolic profile was significantly altered during intestinal fibrosis development, especially the lipid metabolites. Particularly, dynamic perturbations in lipids were strongly associated with alterations in lipid metabolism-related genes expression. Additionally, six dynamically altered metabolites might serve as biomarkers to identify colitis-related intestinal fibrosis in the murine model. CONCLUSIONS: Intestinal fibrosis in colitis mice might be related to dynamic changes in gene expression and metabolites. These findings could provide new insights into the pathogenesis of intestinal fibrosis.

Mechanism by which oleracein E alleviates TNBS-induced ulcerative colitis.

OBJECTIVE: This study aimed to investigate the effect of oleracein E (OE) in improving 2,4,6-trinitrobenzene sulfonic acid (TNBS)-induced ulcerative colitis (UC). METHODS: Lipopolysaccharide (LPS) was used to induce a UC cell model, and TNBS was used to induce a UC rat model. ELISA was performed to assess the levels of inflammatory factors (IL-1ß, TNF-α, and IL-6). Moreover, the activities of catalase (CAT), myeloperoxidase (MPO), and malonaldehyde (MDA) were detected by kits. Western blotting was performed to assess related proteins of the Nrf2/HO-1 signaling pathway, tight junction protein (ZO-1, Occludin, and claudin-2) expression levels, and apoptosis-related proteins (Bcl2, Bax, and cleaved caspase 3). Flow cytometry was used to analyze ROS levels. The morphology of colon tissues and the apoptosis of cells were detected by HE and TUNEL staining, respectively. RESULTS: OE significantly increased the activity of CAT and decreased the activity of MPO in LPS-induced Caco-2 cells and TNBS-induced UC rats. However, the levels of IL-1ß, IL-6, and TNF-α were markedly reduced both in vivo and in vitro. In addition, OE significantly increased the levels of Nrf2/HO-1 signaling pathway-related proteins and tight junction proteins and inhibited cell apoptosis. HE staining showed that OE significantly decreased the severity of acute TNBS-induced colitis in rats. CONCLUSION: OE may exert a regulatory effect on ameliorating intestinal barrier injury and reducing inflammation and oxidative stress levels by activating the Nrf2/HO-1 pathway.

Lactic Acid Bacteria Isolated from Human Breast Milk Improve Colitis Induced by 2,4,6-Trinitrobenzene Sulfonic Acid by Inhibiting NF-κB Signaling in Mice.

Inflammatory bowel disease (IBD), a chronic inflammatory disease, results from dysregulation of the immune responses. Some lactic acid bacteria (LAB), including Lactobacillus, alleviate IBD through immunomodulation. In this study, the anti-colitis effect of LAB isolated from human breast milk was investigated in a mouse model induced acute colitis with 2,4,6-trinitrobenzene sulfonic acid (TNBS). TNBS remarkably increased weight loss, colon shortening, and colonic mucosal proliferation, as well as the expression levels of inflammatory cytokines, including tumor necrosis factor-alpha (TNF-α) and interleukin (IL)-1ß. Oral administration of LAB isolated from human breast milk resulted in a reduction in TNBS-induced colon shortening, as well as induced cyclooxygenase (COX)-2, nitric oxide synthase (iNOS), nuclear factor-kappa B (NF-κB). In addition, LAB suppressed inflammatory cytokines such as TNF-α, IL-6, and IL-1ß, and thus showed an effect of suppressing the level of inflammation induced by TNBS. Furthermore, LAB alleviated gut microbiota dysbiosis, and inhibited intestinal permeability by increasing the expression of intestinal tight junction protein including ZO-1. Collectively, these results suggest that LAB isolated from human breast milk can be used as a functional food for colitis treatment by regulating NF-κB signaling, gut microbiota and increasing expression of intestinal tight junction protein.