Neohesperidin Dihydrochalcone Ameliorates Experimental Colitis via Anti-Inflammatory, Antioxidative, and Antiapoptosis Effects.

Neohesperidin dihydrochalcone (NHDC) is a citrus-originated, seminatural sweetener. There is no investigation concerning the effect of NHDC on ulcerative colitis. The purpose of this study was to determine the therapeutic and protective effects of NHDC in Wistar Albino rats. NHDC was given for 7 days after or before colitis induction. The results showed that NHDC significantly reduced the interleukin-6 (IL-6), interleukin-10 (IL-10), transforming growth factor-ß1 (TGF-ß1), tumor necrosis factor-α (TNF-α), and interferon-γ (IFN-γ) levels. Catalase levels did not show a significant difference between the groups. NHDC provided a remarkable decrease in the expression levels of cyclooxygenase-2 (COX-2), myeloperoxidase (MPO), malondialdehyde (MDA), 8-hydroxy-2'-deoxyguanosine (8-OHdG), and nuclear factor kappa B (NF-κB). Total antioxidant status (TAS) levels were significantly elevated in NHDC treatment groups, while total oxidant status (TOS) and oxidative stress index (OSI) levels were significantly decreased. NHDC provided remarkable improvement in histological symptoms such as epithelial erosion, edema, mucosal necrosis, inflammatory cell infiltration, and hemorrhage. Also, caspase-3 expression levels were statistically decreased in NHDC treatment groups. The results indicated that NHDC might be a protection or alternative treatment for ulcerative colitis.

Ginkgetin improved experimental colitis by inhibiting intestinal epithelial cell apoptosis through EGFR/PI3K/AKT signaling.

Excessive apoptosis of intestinal epithelial cells leads to intestinal barrier dysfunction, which is not only one of the pathological features of inflammatory bowel disease (IBD) but also a therapeutic target. A natural plant extract, Ginkgetin (GK), has been reported to have anti-apoptotic activity, but its role in IBD is unknown. This study aimed to explore whether GK has anti-colitis effects and related mechanisms. An experimental colitis model induced by dextran sulfate sodium (DSS) was established, and GK was found to relieve colitis in DSS-induced mice as evidenced by improvements in weight loss, colon shortening, Disease Activity Index (DAI), macroscopic and tissue scores, and proinflammatory mediators. In addition, in DSS mice and TNF-α-induced colonic organoids, GK protected the intestinal barrier and inhibited intestinal epithelial cell apoptosis, by improving permeability and inhibiting the number of apoptotic cells and the expression of key apoptotic regulators (cleaved caspase 3, Bax and Bcl-2). The underlying mechanism of GK's protective effect was explored by bioinformatics, rescue experiments and molecular docking, and it was found that GK might directly target and activate EGFR, thereby interfering with PI3K/AKT signaling to inhibit apoptosis of intestinal epithelial cells in vivo and in vitro. In conclusion, GK inhibited intestinal epithelial apoptosis in mice with experimental colitis, at least in part, by activating EGFR and interfering with PI3K/AKT activation, explaining the underlying mechanism for ameliorating colitis, which may provide new options for the treatment of IBD.

Orally administrated liquid metal agents for inflammation-targeted alleviation of inflammatory bowel diseases.

Rapid drug clearance and off-target effects of therapeutic drugs can induce low bioavailability and systemic side effects and gravely restrict the therapeutic effects of inflammatory bowel diseases (IBDs). Here, we propose an amplifying targeting strategy based on orally administered gallium (Ga)-based liquid metal (LM) nano-agents to efficiently eliminate reactive oxygen and nitrogen species (RONS) and modulate the dysregulated microbiome for remission of IBDs. Taking advantage of the favorable adhesive activity and coordination ability of polyphenol structure, epigallocatechin gallate (EGCG) is applied to encapsulate LM to construct the formulations (LM-EGCG). After adhering to the inflamed tissue, EGCG not only eliminates RONS but also captures the dissociated Ga to form EGCG-Ga complexes for enhancive accumulation. The detained composites protect the intestinal barrier and modulate gut microbiota for restoring the disordered enteral microenvironment, thereby relieving IBDs. Unexpectedly, LM-EGCG markedly decreases the Escherichia_Shigella populations while augmenting the abundance of Akkermansia and Bifidobacterium, resulting in favorable therapeutic effects against the dextran sulfate sodium-induced colitis.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

CRIg+ macrophages deficiency enhanced inflammation damage in IBD due to gut extracellular vesicles containing microbial DNA.

Gut microbiota-derived extracellular vesicles (mEVs) are reported to regulate inflammatory response by delivering bacterial products into host cells. The complement receptor of the immunoglobulin superfamily macrophages (CRIg+ Mφ) could clear invading bacteria and their derivatives. Here, we investigate the role of CRIg+ Mφ and the mechanism by which mEVs regulate intestinal inflammation. We found that it is exacerbated in IBD patients and colitis mice by mEVs' leakage from disturbed gut microbiota, enriching microbial DNA in the intestinal mucosa. CRIg+ Mφ significantly decrease in IBD patients, allowing the spread of mEVs into the mucosa. The microbial DNA within mEVs is the key trigger for inflammation and barrier function damage. The cGAS/STING pathway is crucial in mEVs-mediated inflammatory injury. Blocking cGAS/STING signaling effectively alleviates inflammation caused by mEVs leakage and CRIg+ Mφ deficiency. Microbial DNA-containing mEVs, along with CRIg+ Mφ deficiency, stimulate inflammation in IBD, with the cGAS/STING pathway playing a crucial role.

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.

Interfacial-engineered living drugs with "ON/OFF" switching for oral delivery.

Living drugs offer a new frontier in medicine, paving the way for personalized and potentially curative treatments. A customized living drug generally requires specialized technologies for highly effective and selective delivery to lesion locations. In this study, we explored an interfacial engineering method for living drugs by wrapping them with a "stealth coating", achieving "ON/OFF" switching of the communications between probiotics and the gastrointesinal (GI) tract. This maximized the bioactivity of living drugs following oral administration to exempt acidic insults and then significantly improved the retention through the gastrointestinal tract. With the notable ability to improve oral availability, the interfacial-engineered living drugs represent remarkable effects for enhanced oral delivery and treatment efficacy in the dextran sulfate sodium (DSS)-induced acute colitis model. We believe that this work has the potential to revolutionize medicine by precisely targeting and increasing curative activity in the future of disease treatment.

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.