Allium tuberosum-derived nanovesicles with anti-inflammatory properties prevent DSS-induced colitis and modify the gut microbiome.

Edible plant-derived nanovesicles (ePDNs) have shown potential as a non-pharmacological option for inflammatory bowel disease (IBD) by maintaining gut health and showing anti-inflammatory effects. However, the effects of Allium tuberosum-derived nanovesicles (ADNs) on colitis have not been studied to date. Here, we extracted exosome-like nanovesicles from Allium tuberosum and investigated whether they have an anti-inflammatory effect in RAW 264.7 cells and colitis mice. The results showed that ADNs reduced the elevated levels of inflammatory factors such as IL-1ß, IL-6, TNF-α, and NF-κB pathway-related proteins as a consequence of lipopolysaccharide (LPS) stimulation in RAW 264.7 cells. Furthermore, our mouse experiments demonstrated that ADNs could ameliorate dextran sulfate sodium (DSS)-induced colitis symptoms (e.g., increased disease activity index score, intestinal permeability, and histological appearance). Additionally, ADNs counteracted DSS-induced colitis by downregulating the expression of serum amyloid A (SAA), IL-1ß, IL-6, and TNF-α and increasing the expression of tight junction proteins (ZO-1 and occludin) and the anti-inflammatory cytokine IL-10. 16S rRNA gene sequencing showed that ADN intervention restored the gut microbial composition, which was similar to that of the DSS non-treated group, by decreasing the ratio of Firmicutes to Bacteroidetes and the relative abundance of Proteobacteria. Furthermore, ADNs induced acetic acid production along with an increase in the abundance of Lactobacillus. Overall, our findings suggest that ADN supplementation has a crucial role in maintaining gut health and is a novel preventive therapy for IBD.

Ambient Particulate Matter Induces In Vitro Toxicity to Intestinal Epithelial Cells without Exacerbating Acute Colitis Induced by Dextran Sodium Sulfate or 2,4,6-Trinitrobenzenesulfonic Acid.

Inflammatory bowel disease (IBD) is an immunologically complex disorder involving genetic, microbial, and environmental risk factors. Its global burden has continued to rise since industrialization, with epidemiological studies suggesting that ambient particulate matter (PM) in air pollution could be a contributing factor. Prior animal studies have shown that oral PM10 exposure promotes intestinal inflammation in a genetic IBD model and that PM2.5 inhalation exposure can increase intestinal levels of pro-inflammatory cytokines. PM10 and PM2.5 include ultrafine particles (UFP), which have an aerodynamic diameter of <0.10 µm and biophysical and biochemical properties that promote toxicity. UFP inhalation, however, has not been previously studied in the context of murine models of IBD. Here, we demonstrated that ambient PM is toxic to cultured Caco-2 intestinal epithelial cells and examined whether UFP inhalation affected acute colitis induced by dextran sodium sulfate and 2,4,6-trinitrobenzenesulfonic acid. C57BL/6J mice were exposed to filtered air (FA) or various types of ambient PM reaerosolized in the ultrafine size range at ~300 µg/m3, 6 h/day, 3-5 days/week, starting 7-10 days before disease induction. No differences in weight change, clinical disease activity, or histology were observed between the PM and FA-exposed groups. In conclusion, UFP inhalation exposure did not exacerbate intestinal inflammation in acute, chemically-induced colitis models.

Urolithin A-mediated augmentation of intestinal barrier function through elevated secretory mucin synthesis.

Maintaining the mucus layer is crucial for the innate immune system. Urolithin A (Uro A) is a gut microbiota-derived metabolite; however, its effect on mucin production as a physical barrier remains unclear. This study aimed to elucidate the protective effects of Uro A on mucin production in the colon. In vivo experiments employing wild-type mice, NF-E2-related factor 2 (Nrf2)-deficient mice, and wild-type mice treated with an aryl hydrocarbon receptor (AhR) antagonist were conducted to investigate the physiological role of Uro A. Additionally, in vitro assays using mucin-producing cells (LS174T) were conducted to assess mucus production following Uro A treatment. We found that Uro A thickened murine colonic mucus via enhanced mucin 2 expression facilitated by Nrf2 and AhR signaling without altering tight junctions. Uro A reduced mucosal permeability in fluorescein isothiocyanate-dextran experiments and alleviated dextran sulfate sodium-induced colitis. Uro A treatment increased short-chain fatty acid-producing bacteria and propionic acid concentration. LS174T cell studies confirmed that Uro A promotes mucus production through the AhR and Nrf2 pathways. In conclusion, the enhanced intestinal mucus secretion induced by Uro A is mediated through the actions of Nrf-2 and AhR, which help maintain intestinal barrier function.

Update: Induction of Inflammatory Bowel Disease in Immunodeficient Mice by Injection of Naïve CD4+ T cells (T Cell Transfer Model of Colitis).

The intestinal inflammation induced by injection of naïve CD4+ T cells into lymphocyte-deficient hosts (more commonly known as the T cell transfer model of colitis) shares many features of idiopathic inflammatory bowel disease (IBD) in humans, such as epithelial cell hyperplasia, crypt abscess formation, and dense lamina propria lymphocyte infiltration. As such, it provides a useful tool for studying mucosal immune regulation as it relates to the pathogenesis and treatment of IBD in humans. In the IBD model described here, colitis is induced in Rag (recombination-activating gene)-deficient mice by reconstitution of these mice with naïve CD4+CD45RBhi T cells through adoptive T cell transfer. Although different recipient hosts of cell transfer can be used, Rag-deficient mice are the best characterized and support studies that are both flexible and reproduceable. As described in the Basic Protocol, in most studies the transferred cells consist of naïve CD4+ T cells (CD45RBhi T cells) derived by fluorescence-activated cell sorting from total CD4+ T cells previously purified using immunomagnetic negative selection beads. In a Support Protocol, methods to characterize colonic disease progression are described, including the monitoring of weight loss and diarrhea and the histological assessment of colon pathology. © 2024 The Author(s). Current Protocols published by Wiley Periodicals LLC. Basic Protocol: Induction of IBD in Rag-deficient mice by the transfer of naïve CD4+CD45RBhi T cells Support Protocol: Monitoring development of colitis.

Therapeutic potential of the secreted Kazal-type serine protease inhibitor SPINK4 in colitis.

Mucus injury associated with goblet cell (GC) depletion constitutes an early event in inflammatory bowel disease (IBD). Using single-cell sequencing to detect critical events in mucus dysfunction, we discover that the Kazal-type serine protease inhibitor SPINK4 is dynamically regulated in colitic intestine in parallel with disease activities. Under chemically induced colitic conditions, the grim status in Spink4-conditional knockout mice is successfully rescued by recombinant murine SPINK4. Notably, its therapeutic potential is synergistic with existing TNF-α inhibitor infliximab in colitis treatment. Mechanistically, SPINK4 promotes GC differentiation using a Kazal-like motif to modulate EGFR-Wnt/ß-catenin and -Hippo pathways. Microbiota-derived diacylated lipoprotein Pam2CSK4 triggers SPINK4 production. We also show that monitoring SPINK4 in circulation is a reliable noninvasive technique to distinguish IBD patients from healthy controls and assess disease activity. Thus, SPINK4 serves as a serologic biomarker of IBD and has therapeutic potential for colitis via intrinsic EGFR activation in intestinal homeostasis.

Weissella paramesenteroides NRIC1542 inhibits dextran sodium sulfate-induced colitis in mice through regulating gut microbiota and SIRT1/NF-κB signaling pathway.

Inflammatory bowel disease (IBD) is a kind of recurrent inflammatory disorder of the intestinal tract. The purpose of this study was to investigate the effects of Weissella paramesenteroides NRIC1542 on colitis in mice. A colitis model was induced by adding 1.5% DSS to sterile distilled water for seven consecutive days. During this process, mice were administered different concentrations of W. paramesenteroides NRIC1542. Colitis was assessed by DAI, colon length and hematoxylin-eosin staining of colon sections. The expressions of NF-κB signaling proteins and the tight junction proteins ZO-1 and occludin were detected by western blotting, and the gut microbiota was analyzed by 16S rDNA. The results showed that W. paramesenteroides NRIC1542 significantly reduced the degree of pathological tissue damage and the levels of TNF-α and IL-1ß in colonic tissue, inhibiting the NF-κB signaling pathway and increasing the expression of SIRT1, ZO-1 and occludin. In addition, W. paramesenteroides NRIC1542 can modulate the structure of the gut microbiota, characterized by increased relative abundance of Muribaculaceae_unclassified, Paraprevotella, Prevotellaceae_UCG_001 and Roseburia, and decrease the relative abundance of Akkermansia and Alloprevotella induced by DSS. The above results suggested that W. paramesenteroides NRIC1542 can protect against DSS-induced colitis in mice through anti-inflammatory, intestinal barrier maintenance and flora modulation.

Body-wide genetic deficiency of poly(ADP-ribose) polymerase 14 sensitizes mice to colitis.

Inflammatory bowel disease (IBD) is a chronic disease of the gastrointestinal tract affecting millions of people. Here, we investigated the expression and functions of poly(ADP-ribose) polymerase 14 (Parp14), an important regulatory protein in immune cells, with an IBD patient cohort as well as two mouse colitis models, that is, IBD-mimicking oral dextran sulfate sodium (DSS) exposure and oral Salmonella infection. Parp14 was expressed in the human colon by cells in the lamina propria, but, in particular, by the epithelial cells with a granular staining pattern in the cytosol. The same expression pattern was evidenced in both mouse models. Parp14-deficiency caused increased rectal bleeding as well as stronger epithelial erosion, Goblet cell loss, and immune cell infiltration in DSS-exposed mice. The absence of Parp14 did not affect the mouse colon bacterial microbiota. Also, the colon leukocyte populations of Parp14-deficient mice were normal. In contrast, bulk tissue RNA-Seq demonstrated that the colon transcriptomes of Parp14-deficient mice were dominated by abnormalities in inflammation and infection responses both prior and after the DSS exposure. Overall, the data indicate that Parp14 has an important role in the maintenance of colon epithelial barrier integrity. The prognostic and predictive biomarker potential of Parp14 in IBD merits further investigation.

Disruption of intestinal oxygen balance in acute colitis alters the gut microbiome.

The juxtaposition of well-oxygenated intestinal colonic tissue with an anerobic luminal environment supports a fundamentally important relationship that is altered in the setting of intestinal injury, a process likely to be relevant to diseases such as inflammatory bowel disease. Herein, using two-color phosphorometry to non-invasively quantify both intestinal tissue and luminal oxygenation in real time, we show that intestinal injury induced by DSS colitis reduces intestinal tissue oxygenation in a spatially defined manner and increases the flux of oxygen from the tissue into the gut lumen. By characterizing the composition of the microbiome in both DSS colitis-affected gut and in a bioreactor containing a stable human fecal community exposed to microaerobic conditions, we provide evidence that the increased flux of oxygen into the gut lumen augments glycan degrading bacterial taxa rich in glycoside hydrolases which are known to inhabit gut mucosal surface. Continued disruption of the intestinal mucus barrier through such a mechanism may play a role in the perpetuation of the intestinal inflammatory process.

Mesenteric lymph nodes: a critical site for the up-regulatory effect of hUC-MSCs on Treg cells by producing TGF-ß1 in colitis treatment.

BACKGROUND: Mesenchymal stem cells (MSCs) demonstrate a wide range of therapeutic capabilities in the treatment of inflammatory bowel disease (IBD). The intraperitoneal injection of MSCs has exhibited superior therapeutic efficacy on IBD than intravenous injection. Nevertheless, the precise in vivo distribution of MSCs and their biological consequences following intraperitoneal injection remain inadequately understood. Additional studies are required to explore the correlation between MSCs distribution and their biological effects. METHODS: First, the distribution of human umbilical cord MSCs (hUC-MSCs) and the numbers of Treg and Th17 cells in mesenteric lymph nodes (MLNs) were analyzed after intraperitoneal injection of hUC-MSCs. Subsequently, the investigation focused on the levels of transforming growth factor beta1 (TGF-ß1), a key cytokine to the biology of both Treg and Th17 cells, in tissues of mice with colitis, particularly in MLNs. The study also delved into the impact of hUC-MSCs therapy on Treg cell counts in MLNs, as well as the consequence of TGFB1 knockdown hUC-MSCs on the differentiation of Treg cells and the treatment of IBD. RESULTS: The therapeutic effectiveness of intraperitoneally administered hUC-MSCs in the treatment of colitis was found to be significant, which was closely related to their quick migration to MLNs and secretion of TGF-ß1. The abundance of hUC-MSCs in MLNs of colitis mice is much higher than that in other organs even the inflamed sites of colon. Intraperitoneal injection of hUC-MSCs led to a significant increase in the number of Treg cells and a decrease in Th17 cells especially in MLNs. Furthermore, the concentration of TGF-ß1, the key cytokine for Treg differentiation, were also found to be significantly elevated in MLNs after hUC-MSCs treatment. Knockdown of TGFB1 in hUC-MSCs resulted in a noticeable reduction of Treg cells in MLNs and the eventually failure of hUC-MSCs therapy in colitis. CONCLUSIONS: MLNs may be a critical site for the regulatory effect of hUC-MSCs on Treg/Th17 cells and the therapeutic effect on colitis. TGF-ß1 derived from hUC-MSCs promotes local Treg differentiation in MLNs. This study will provide new ideas for the development of MSC-based therapeutic strategies in IBD patients.

Upregulation of TCPTP in Macrophages Is Involved in IL-35 Mediated Attenuation of Experimental Colitis.

Ulcerative colitis (UC) is a chronic intestinal inflammatory disease with complex etiology. Interleukin-35 (IL-35), as a cytokine with immunomodulatory function, has been shown to have therapeutic effects on UC, but its mechanism is not yet clear. Therefore, we constructed Pichia pastoris stably expressing IL-35 which enables the cytokines to reach the diseased mucosa, and explored whether upregulation of T-cell protein tyrosine phosphatase (TCPTP) in macrophages is involved in the mechanisms of IL-35-mediated attenuation of UC. After the successful construction of engineered bacteria expressing IL-35, a colitis model was successfully induced by giving BALB/c mice a solution containing 3% dextran sulfate sodium (DSS). Mice were treated with Pichia/IL-35, empty plasmid-transformed Pichia (Pichia/0), or PBS by gavage, respectively. The expression of TCPTP in macrophages (RAW264.7, BMDMs) and intestinal tissues after IL-35 treatment was detected. After administration of Pichia/IL-35, the mice showed significant improvement in weight loss, bloody stools, and shortened colon. Colon pathology also showed that the inflammatory condition of mice in the Pichia/IL-35 treatment group was alleviated. Notably, Pichia/IL-35 treatment not only increases local M2 macrophages but also decreases the expression of inflammatory cytokine IL-6 in the colon. With Pichia/IL-35 treatment, the proportion of M1 macrophages, Th17, and Th1 cells in mouse MLNs were markedly decreased, while Tregs were significantly increased. In vitro experiments, IL-35 significantly promoted the expression of TCPTP in macrophages stimulated with LPS. Similarly, the mice in the Pichia/IL-35 group also expressed more TCPTP than that of the untreated group and the Pichia/0 group.

Corrigendum to: Mechanism of HSP90 Inhibitor in the Treatment of DSS-induced Colitis in Mice by Inhibiting MAPK Pathway and Synergistic Effect of Compound Sophorae Decoction.

A typographical error appeared in the title of the article "Mechanism of HSP90 Inhibitor in the Treatment of DSS-induced Colitis in Mice by Inhibiting MAPK Pathway and Synergistic Effect of Compound Sophora Decoction", published in Current Pharmaceutical Design, 2022; 28(42): 3456-3468 [1]. Details of the error and a correction are provided below. Original: Mechanism of HSP90 Inhibitor in the Treatment of DSS-induced Colitis in Mice by Inhibiting MAPK Pathway and Synergistic Effect of Compound Sophora Decoction Corrected: Mechanism of HSP90 Inhibitor in the Treatment of DSS-induced Colitis in Mice by Inhibiting MAPK Pathway and Synergistic Effect of Compound Sophorae Decoction We regret the error and apologize to readers. The original article can be found online at: https://www.eurekaselect.com/article/127740.

Ribonuclease 4 functions as an intestinal antimicrobial protein to maintain gut microbiota and metabolite homeostasis.

Antimicrobial proteins contribute to host-microbiota interactions and are associated with inflammatory bowel disease (IBD), but our understanding on antimicrobial protein diversity and functions remains incomplete. Ribonuclease 4 (Rnase4) is a potential antimicrobial protein with no known function in the intestines. Here we find that RNASE4 is expressed in intestinal epithelial cells (IEC) including Paneth and goblet cells, and is detectable in human and mouse stool. Results from Rnase4-deficient mice and recombinant protein suggest that Rnase4 kills Parasutterella to modulate intestinal microbiome, thereby enhancing indoleamine-2,3-dioxygenase 1 (IDO1) expression and subsequently kynurenic and xanthurenic acid production in IECs to reduce colitis susceptibility. Furthermore, deceased RNASE4 levels are observed in the intestinal tissues and stool from patients with IBD, correlating with increased stool Parasutterella. Our results thus implicate Rnase4 as an intestinal antimicrobial protein regulating gut microbiota and metabolite homeostasis, and as a potential diagnostic biomarker and therapeutic target for IBD.

Estrogen deprivation and estrogen receptor α antagonism decrease DSS colitis in female mice.

The association of hormonal contraception with increased risk of inflammatory bowel disease (IBD) observed in females suggests involvement of ovarian hormones, such as estradiol, and the estrogen receptors in the progression of intestinal inflammation. Here, we investigated the effects of prophylactic SERM2 and estradiol supplementation in dextran sulfate sodium-induced colitis using mice with intact ovaries and ovariectomized (OVX) female mice. We found that graded colitis score was threefold reduced in the OVX mice, compared to mice with intact ovaries. Estradiol supplementation, however, aggravated the colitis in OVX mice, increasing the colitis score to a similar level than what was observed in the intact mice. Further, we observed that immune infiltration and gene expression of inflammatory interleukins Il1b, Il6, and Il17a were up to 200-fold increased in estradiol supplemented OVX colitis mice, while a mild but consistent decrease was observed by SERM2 treatment in intact animals. Additionally, cyclo-oxygenase 2 induction was increased in the colon of colitis mice, in correlation with increased serum estradiol levels. Measured antagonist properties of SERM2, together with the other results presented here, indicates an exaggerating role of ERα signaling in colitis. Our results contribute to the knowledge of ovarian hormone effects in colitis and encourage further research on the potential use of ER antagonists in the colon, in order to alleviate inflammation.

Homotherapy for heteropathy: therapeutic effect of Butein in NLRP3-driven diseases.

BACKGROUND: Aberrant inflammatory responses drive the initiation and progression of various diseases, and hyperactivation of NLRP3 inflammasome is a key pathogenetic mechanism. Pharmacological inhibitors of NLRP3 represent a potential therapy for treating these diseases but are not yet clinically available. The natural product butein has excellent anti-inflammatory activity, but its potential mechanisms remain to be investigated. In this study, we aimed to evaluate the ability of butein to block NLRP3 inflammasome activation and the ameliorative effects of butein on NLRP3-driven diseases. METHODS: Lipopolysaccharide (LPS)-primed bone-marrow-derived macrophages were pretreated with butein and various inflammasome stimuli. Intracellular potassium levels, ASC oligomerization and reactive oxygen species production were also detected to evaluate the regulatory mechanisms of butein. Moreover, mouse models of LPS-induced peritonitis, dextran sodium sulfate-induced colitis, and high-fat diet-induced non-alcoholic steatohepatitis were used to test whether butein has protective effects on these NLRP3-driven diseases. RESULTS: Butein blocks NLRP3 inflammasome activation in mouse macrophages by inhibiting ASC oligomerization, suppressing reactive oxygen species production, and upregulating the expression of the antioxidant pathway nuclear factor erythroid 2-related factor 2 (Nrf2). Importantly, in vivo experiments demonstrated that butein administration has a significant protective effect on the mouse models of LPS-induced peritonitis, dextran sodium sulfate-induced colitis, and high-fat diet-induced non-alcoholic steatohepatitis. CONCLUSION: Our study illustrates the connotation of homotherapy for heteropathy, i.e., the application of butein to broaden therapeutic approaches and treat multiple inflammatory diseases driven by NLRP3.

Neuroimmune response and oxidative stress in the prefrontal cortex mediate seizure susceptibility in experimental colitis in male mice.

Inflammatory bowel disease (IBD) is a chronic gastrointestinal disorder. Oxidative stress and inflammatory responses have a vital role in the pathophysiology of IBD as well as seizure. IBD is associated with extraintestinal manifestations. This study aimed to explore the relationship between colitis and susceptibility to seizures, with a focus on the roles of neuroinflammation and oxidative stress in acetic acid-induced colitis in mice. Forty male Naval Medical Research Institute mice were divided into four groups: control, colitis, pentylenetetrazole (PTZ), and colitis + PTZ. Colitis was induced by intrarectal administration of acetic acid, and seizures were induced by intravenous injection of PTZ 7 days postcolitis induction. Following the measurement of latency to seizure, the mice were killed, and their colons and prefrontal cortex (PFC) were dissected. Gene expression of inflammatory markers including interleukin-1ß, tumor necrosis factor-alpha, NOD-like receptor protein 3, and toll-like receptor 4, as well as total antioxidant capacity (TAC), malondialdehyde (MDA), and nitrite levels were measured in the colon and PFC. Histopathological evaluations were performed on the colon samples. Data were analyzed by t-test or one-way variance analysis. Colitis decreased latency to seizure, increased gene expression of inflammatory markers, and altered levels of MDA, nitrite, and TAC in both the colon and PFC. Simultaneous induction of colitis and seizure exacerbated the neuroimmune response and oxidative stress in the PFC and colon. Results concluded that neuroinflammation and oxidative stress in the PFC at least partially mediate the comorbid decrease in seizure latency in mice with colitis.

Matrine Ameliorates DSS-Induced Colitis by Suppressing Inflammation, Modulating Oxidative Stress and Remodeling the Gut Microbiota.

Matrine (MT) possesses anti-inflammatory, anti-allergic and antioxidative properties. However, the impact and underlying mechanisms of matrine on colitis are unclear. The purpose of this research was to examine the protective impact and regulatory mechanism of matrine on dextran sulfate sodium (DSS)-induced ulcerative colitis (UC) in mice. MT alleviated DSS-induced UC by inhibiting weight loss, relieving colon shortening and reducing the disease activity index (DAI). Moreover, DSS-induced intestinal injury and the number of goblet cells were reversed by MT, as were alterations in the expression of zonula occludens-1 (ZO-1) and occludin in colon. Simultaneously, matrine not only effectively restored DSS-induced oxidative stress in colonic tissues but also reduced the production of inflammatory cytokines. Furthermore, MT could treat colitis mice by regulating the regulatory T cell (Treg)/T helper 17 (Th17) cell imbalance. We observed further evidence that MT alleviated the decrease in intestinal flora diversity, reduced the proportion of Firmicutes and Bacteroidetes, decreased the proportion of Proteobacteria and increased the relative abundance of Lactobacillus and Akkermansia in colitis mice. In conclusion, these results suggest that MT may mitigate DSS-induced colitis by enhancing the colon barrier integrity, reducing the Treg/Th17 cell imbalance, inhibiting intestinal inflammation, modulating oxidative stress and regulating the gut microbiota. These findings provide strong evidence for the development and application of MT as a dietary treatment for UC.

TL1A Promotes Fibrogenesis in Colonic Fibroblasts via the TGF-ß1/Smad3 Signaling Pathway.

OBJECTIVE: Intestinal fibrosis is a refractory complication of inflammatory bowel disease (IBD). Tumor necrosis factor ligand-related molecule-1A (TL1A) is important for IBD-related intestinal fibrosis in a dextran sodium sulfate (DSS)-induced experimental colitis model. This study aimed to explore the effects of TL1A on human colonic fibroblasts. METHODS: A trinitrobenzene sulfonic acid (TNBS)-induced experimental colitis model of LCK-CD2-TL1A-GFP transgenic (Tg) or wild-type (WT) mice was established to determine the effect and mechanism of TL1A on intestinal fibrosis. The human colonic fibroblast CCD-18Co cell line was treated concurrently with TL1A and human peripheral blood mononuclear cell (PBMC) supernatant. The proliferation and activation of CCD-18Co cells were detected by BrdU assays, flow cytometry, immunocytochemistry and Western blotting. Collagen metabolism was tested by Western blotting and real-time quantitative polymerase chain reaction (RT-qPCR). RESULTS: The level of collagen metabolism in the TNBS+ethyl alcohol (EtOH)/Tg group was greater than that in the TNBS+EtOH/WT group. Transforming growth factor-ß1 (TGF-ß1) and p-Smad3 in the TNBS+EtOH/Tg group were upregulated as compared with those in the TNBS+EtOH/WT group. The proliferation of CCD-18Co cells was promoted by the addition of human PBMC supernatant supplemented with 20 ng/mL TL1A, and the addition of human PBMC supernatant and TL1A increased CCD-18Co proliferation by 24.4% at 24 h. TL1A promoted cell activation and increased the levels of COL1A2, COL3A1, and TIMP-1 in CCD-18Co cells. Treatment of CCD-18Co cells with TL1A increased the expression of TGF-ß1 and p-Smad3. CONCLUSION: TL1A promotes TGF-ß1-mediated intestinal fibroblast activation, proliferation, and collagen deposition and is likely related to an increase in the TGF-ß1/Smad3 signaling pathway.

Gut microbiota and D-ribose mediate the anti-colitic effect of punicalagin in DSS-treated mice.

Background: Inflammatory bowel disease (IBD) is an increasing health burden worldwide. Punicalagin, a bioactive component rich in pomegranate rind, has been shown to attenuate chemical or bacteria-induced experimental colitis in mice, but whether punicalagin exerts its function through modulating gut microbiota and metabolites remains unexplored. Results: Punicalagin (100 mg per kg per day) administered orally to mice alleviated dextran-sodium sulfate (DSS)-induced colitis. Gut microbiota analyzed by 16S rRNA sequencing showed that punicalagin altered gut microbiota by increasing the Lachnospiraceae_NK4A136_group and Bifidobacterium abundance. To evaluate the effect of punicalagin-modulated microbiota and its metabolites in colitis mice, we transplanted fecal microbiota and sterile fecal filtrate (SFF) to mice treated with oral antibiotics. The results of fecal microbiota transplantation (FMT) demonstrated that punicalagin's anti-colitic effect is transferable by transplanting punicalagin-modulated gut microbiota and its metabolites. Additionally, we discovered that punicalagin-modulated sterile fecal filtrate also exhibits anti-colitis effects, as evidenced by improved intestinal barrier integrity and decreased inflammation. Subsequently, fecal metabolites were analyzed using liquid chromatography-mass spectrometry (LC-MS). The analysis revealed that punicalagin significantly increased the level of D-ribose. In vitro experiments showed that D-ribose has both anti-inflammatory and antioxidant properties. Furthermore, D-ribose significantly mitigated DSS-induced colitis symptoms in mice. Conclusions: Overall, this study demonstrated that gut microbiota and its metabolites partly mediate the protective effect of punicalagin against DSS-induced colitis in mice. D-ribose is a key metabolite that contributes to the anti-colitic effect of punicalagin in mice.

Cu,Zn,I-Doped Carbon Dots with Boosted Triple Antioxidant Nanozyme Activity for Treatment of DSS-Induced Colitis.

Nanozyme-mediated antioxidative therapy is a promising star for treating a myriad of important diseases through eliminating excessive reactive oxygen species (ROS) such as O2·- and H2O2, a critical mechanism for inflammatory bowel disease (IBD). This work provides a high biocompatibility iodine-copper-zinc covalent doped carbon dots (Cu,Zn,I-CDs) with the catalase (CAT)-, superoxide dismutase (SOD)- and glutathione peroxidase (GPx)-like catalytic activities for treating ulcerative colitis (UC) by scavenging overproduced ROS. We found that I dopant aids in counteracting the positive charge at Cu,Zn dopants brought on by low pH, enabling Cu,Zn,I-CDs to process strong triple antioxidant nanozyme activities rather than Cu,Zn-CDs. Vitro experiments displayed that the Cu,Zn,I-CDs could scavenge the excessive ROS to protect cellular against oxidative stress and reduce the expression of proinflammatory cytokines, such as TNF-α, IL-1ß, and IL-6. In sodium dextran sulfate (DSS)-induced colitis mice models, Cu,Zn,I-CDs with excellent biocompatibility could effectively relieve the inflammation of the colon, containing the reduction of the colon length, the damaged epithelium, the infiltration of inflammatory cells, and upregulation of antioxidant genes. Therefore, the therapy of Cu,Zn,I-CD antioxidant nanozymes is an effective approach and provides a novel strategy for UC treatment.

Circadian rhythm disruption-mediated downregulation of Bmal1 exacerbates DSS-induced colitis by impairing intestinal barrier.

Background: Circadian rhythm disruption (CRD) is thought to increase the risk of inflammatory bowel disease. The deletion of Bmal1, a core transcription factor, leads to a complete loss of the circadian rhythm and exacerbates the severity of dextran sodium sulfate (DSS)-induced colitis in mice. However, the underlying mechanisms by which CRD and Bmal1 mediate IBD are still unclear. Methods: We used a CRD mouse model, a mouse colitis model, and an in vitro model of colonic epithelial cell monolayers. We also knocked down and overexpressed Bmal1 in Caco-2 cells by transfecting lentivirus in vitro. The collected colon tissue and treated cells were assessed and analyzed using immunohistochemistry, immunofluorescence staining, quantitative reverse transcription-polymerase chain reaction, western blot, flow cytometry, transmission electron microscopy, and terminal deoxynucleotidyl transferase-mediated dUTP nick-end labelling staining. Results: We found that CRD mice with downregulated Bmal1 expression were more sensitive to DSS-induced colitis and had more severely impaired intestinal barrier function than wild-type mice. Bmal1-/- mice exhibited more severe colitis, accompanied by decreased tight junction protein levels and increased apoptosis of intestinal epithelial cells compared with wild-type mice, which were alleviated by using the autophagy agonist rapamycin. Bmal1 overexpression attenuated Lipopolysaccharide-induced apoptosis of intestinal epithelial cells and impaired intestinal epithelial cells barrier function in vitro, while inhibition of autophagy reversed this protective effect. Conclusion: This study suggests that CRD leads to the downregulation of Bmal1 expression in the colon, which may exacerbate DSS-induced colitis in mice, and that Bmal1 may serve as a novel target for treating inflammatory bowel disease.