Animal Models Of Colitis Research Articles

Preclinical studies of natural flavonoids in inflammatory bowel disease based on macrophages: a systematic review with meta-analysis and network pharmacology.

Flavonoid is a category of bioactive polyphenolic compounds that are extensively distributed in plants with specific pharmacological properties, such as anti-inflammatory and anti-oxidant. Importantly, natural flavonoids have shown the protected function on the dextran sulfate sodium (DSS)-induced colitis in animals and lipopolysaccharides (LPS)-induced inflammatory response in macrophages. The purpose of this systematic review is to explore the efficacy of natural flavonoids in animal models of IBD (inflammatory bowel disease) and potential mechanisms in macrophages by meta-analysis and network pharmacology in preclinical studies. Relevant foundation studies were searched from January 2010 to November 2023 in databases like PubMed, Elsevier ScienceDirect, and Web of Science. Then, OriginPro software was used to extract values from images, and the analysis was performed using Review Manager 5.3. The retrieved data was analyzed according to the fixed-effects model and random-effects model. Subsequently, heterogeneity was evaluated using the I2 statistics. Lastly, network pharmacology was applied to confirm mechanisms of natural flavonoids on IBD. According to the results of meta-analysis, we found the natural flavonoids exhibited powerful therapeutic effects against IBD, which not only reversed colonic shortness (WMD = 1.33, 95% CI (1.07, 1.59), P < 0.00001), but also reduced histological score (SMD = - 2.66, 95% CI (- 3.77, - 1.95), P < 0.00001) between natural flavonoid treatment groups compared with the experimental IBD model. Furthermore, treatment with natural flavonoids decreased the levels of tumor necrosis factor-α (TNF-α) in macrophages. Mechanistically, our summarized data substantiate that natural flavonoids alleviate LPS-induced M1 macrophage polarization, anti-oxidant, anti-inflammatory, maintain intestinal barrier, and inhibit the activation of the NLR family pyrin domain containing 3 (NLRP3) inflammasome in macrophages. Moreover, the results of network pharmacology also support this. This systematic review demonstrated the efficiency of natural flavonoids in treating IBD in preclinical research by meta-analysis and network pharmacology, which offered supporting evidence for clinical trial implementation. However, some limitations remain present, such as technique quality shortage, missed reports on account of negative results, failure to count sample size, and the risk of bias.

Evaluation of the Protective Effect of Hydroalcoholic and Aqueous Extracts of Ulmus minor Leaves on Ulcerative Colitis Induced by Acetic Acid in Rats

Background: Ulcerative colitis (UC) is a chronic inflammatory disease of the large intestine that cannot be cured, but its symptoms can be managed. Objectives: This study aimed to evaluate the protective effects of hydroalcoholic and aqueous extracts of Ulmus minor leaves on UC induced by acetic acid in rats. Methods: Rats were randomly divided into seven groups of five, and 3% acetic acid was used to induce colitis. To assess the protective effect of Ulmus minor leaves, macroscopic, microscopic, and histological evaluations were performed on the different study groups. Results: Macroscopic examinations of both the hydroalcoholic and aqueous extract groups showed that the aqueous extract at a dose of 200 mg/kg provided the best protective effect on colon tissue. Rats treated with hydroalcoholic extracts at doses of 100 mg/kg and 200 mg/kg, as well as those treated with aqueous extract at 100 mg/kg, also showed favorable outcomes compared to the control group, with a significant difference (P &lt; 0.05). Furthermore, among the groups treated with hydroalcoholic and aqueous extracts, the aqueous extract at 200 mg/kg demonstrated the most protective effects based on microscopic and histological evaluations of the colon. Conclusions: The extracts of Ulmus minor leaves demonstrated anti-inflammatory properties in an animal model of colitis. Further studies are required to evaluate their potential therapeutic benefits in patients with UC.

A CRISPR mediated point‐of‐care assay for the detection of mucosal calprotectin in an animal model of ulcerative colitis

AbstractInflammatory bowel disease (IBD) is a chronic disorder associated with inflammation in the gastrointestinal tract, leading to a range of debilitating symptoms. Fecal calprotectin is an established biomarker for ulcerative colitis (UC), one of the main IBD diseases, which provides indications of the presence and severity of inflammation in the digestive tract. Enzyme‐Linked Immunosorbent Assay (ELISA) as a gold standard approach for fecal calprotectin detection is time‐consuming and impractical in point‐of‐care settings. Moreover, obtaining fecal samples from patients is challenging and inhibits longitudinal monitoring. To address these specific problems, we have developed a novel approach for detecting calprotectin which leverages clustered regularly interspaced short palindromic repeats (CRISPR)/Cas technology. We successfully developed a portable tube‐based CRISPR/Cas assay for point‐of‐care testing of calprotectin. This assay showed a detection range from 1 to 10,000 ng/ml (over 4 log units), using both fluorescent and colorimetric analytical techniques. The established assay was further validated through measurements in mucosal samples obtained in an anesthetised preclinical rodent model of UC, with 2–3 times higher calprotectin concentration detected in UC rat samples compared to that of healthy control animals. This point‐of‐care test may provide a rapid, precise, and user‐friendly approach for the diagnosis and monitoring of IBD through mucosal sample testing.

Zein: Potential biopolymer in inflammatory bowel diseases.

Effectively managing inflammatory bowel disease (IBD) poses difficulties due to its persistent nature and unpredictable episodes of exacerbation. There is encouraging evidence that personalized medication delivery systems can improve therapy efficacy while reducing the negative effects of standard medicines. Zein, a protein produced from corn, has garnered interest as a possible means of delivering drugs for the treatment of IBD. This review delves into Zein-based drug delivery systems, showcasing its biodegradability, controlled release capabilities, and biocompatibility. Studies have shown that Zein-based nanoparticles, microcarriers, and core-shell microparticles have the capacity to increase medication stability, enhance targeting in the intestines, and decrease toxicity in animal models of IBD. The review highlights the promise of Zein in personalized therapy for IBD and urges more study to enhance its clinical use.

Protective effect of freeze-dried extract of Persicaria bistorta Samp. on acetic acid-induced colitis model in rats: Involvement of nitric oxide and opioid system.

Inflammatory bowel disease is a chronic inflammatory disorder accompanied by occasional flare-ups, abdominal pain, and rectal bleeding.Persicaria bistorta Samp. is a medicinal plant repeatedly mentioned in traditional Persian medicine for the treatment of bleeding and tissue damage in different organs, including the intestines. The current study aimed to evaluate the effect of bistort root in an animal model of colitis. Freeze-dried aqueous extract of the plant (PB) was prepared and analyzed using liquid chromatography-mass spectrometry and high-performance liquid chromatography. The anti-inflammatory effect of oral PB (300, 500, and 700mg/kg) was evaluated in acetic acid-induced colitis in Wistar rats compared with negative control and positive control (dexamethasone). The role of nitric oxide (NO), opioid receptors, Toll-like receptors (TLR-4), interleukin (IL)-1β, IL-6, TNF-α, NF-κB, myeloperoxidase, and intestinal tissue damage using immunohistochemistry staining for cyclooxygenase-2 (COX-2) were also assessed. A total of 29 compounds were identified in the extract. The gallic acid content of the extractwas 4.973 ± 1.102mg/g. PB significantly ameliorated the gross morphological damage from 4.66 ± 0.577 in negative control to 1.33 ± 0.56 in PB 700 (p < 0.001). Also, PB 700 lowered the levels of TNF-α (p < 0.01), TLR-4 (p < 0.001), NF-κB (p < 0.0001), IL-1β (p < 0.0001), and IL-6 (p < 0.0001) compared to the negative control. Additionally, while blocking NO and opioid pathways, the therapeutic effect of the extract was not significant, compared to the negative control, suggesting that PB 700 has exerted its therapeutic effect via these two pathways. However, further mechanistic and clinical studies are recommended to confirm PB as a natural treatment for colitis.

Protective role of seleno-amino acid against IBD via ferroptosis inhibition in enteral nutrition therapy

The interplay between intestinal barrier degradation and trace element insufficiency worsens inflammatory bowel disease (IBD). Selenium (se) is essential for glutathione peroxidase 4 (GPX4) synthesis, which protects against intestinal epithelial cell injury in IBD. However, malnutrition and malabsorption limit the availability of dietary selenium. This study investigated the protective effects of naturally occurring seleno-amino acids on the intestinal barrier in an IBD animal model by promoting GPX4 synthesis. L-se-methylselenocystine (seMc) supplementation reversed decreased GPX4 expression levels, alleviated glutathione depletion and scavenged reactive oxygen species invitro. Invivo, enteral nutrition combined with seMc protected the intestinal barrier and alleviated IBD-related symptoms by inhibiting ferroptosis and reversing lipid peroxidation in epithelial cells while reducing immune cell infiltration. Our findings suggest that seleno-amino acid-based nutritional formulations may provide a basis for nutritional support to alleviate complex cycles between intestinal barrier damage and malnutrition in IBD patients.

Zinc and Inflammatory Bowel Disease: From Clinical Study to Animal Experiment.

Inflammatory bowel disease (IBD) is a chronic inflammatory disease of the gastrointestinal tract (GI) with a high incidence rate globally, and IBD patients are often accompanied by zinc deficiency. This review aims to summarize the potential therapeutic value of zinc supplementation in IBD clinical patients and animal models. Zinc supplementation can relieve the severity of IBD especially in patients with zinc deficiency. The clinical severity of IBD were mainly evaluated through some scoring methods involving clinical performance, endoscopic observation, blood biochemistry, and pathologic biopsy. Through conducting animal experiments, it has been found that zinc plays an important role in alleviating clinical symptoms and improving pathological lesions. In both clinical observation and animal experiment of IBD, the therapeutic mechanisms of zinc interventions have been found to be related to immunomodulation, intestinal epithelial repair, and gut microbiota's balance. Furthermore, the antioxidant activity of zinc was clarified in animal experiment. Appropriate zinc supplementation is beneficial for IBD therapy, and the present evidence highlights that alleviating zinc-deficient status can effectively improve the severity of clinical symptoms in IBD patients and animal models.

Oyster Peptides Ameliorate Dextran Sulfate Sodium-Induced Ulcerative Colitis via Modulating the Gut Microbiota and Inhibiting the TLR4/NF-κB Pathway.

Ulcerative colitis (UC) is an inflammatory bowel disease with an increasing prevalence year over year, and the medications used to treat patients with UC clinically have severe side effects. Oyster peptides (OPs) have anti-inflammatory and antioxidant properties as functional foods that can alleviate a wide range of inflammatory conditions. However, the application of oyster peptides in ulcerative colitis is not well studied. In this work, an animal model of acute colitis was established using 3% dextran sulfate sodium (DSS), and the impact of OP therapy on colitis in mice was examined. Supplementing with OPs prevented DSS-induced colitis from worsening, reduced the expression of oxidative stress and inflammatory markers, and restored the intestinal barrier damage caused by DSS-induced colitis in mice. The 16S rDNA results showed that the OP treatment improved the gut microbiota structure of the UC mice, including increasing microbial diversity, increasing beneficial bacteria, and decreasing harmful bacteria. In the UC mice, the OP therapy decreased the relative abundance of Family_XIII_AD3011_group and Prevotella_9 and increased the relative abundance of Alistipes. In conclusion, OP treatment can inhibit the TLR4/NF-κB pathway and improve the intestinal microbiota in UC mice, which in turn alleviates DSS-induced colitis, providing a reference for the treatment of clinical UC patients.

Therapeutic Prospects of Mesenchymal Stem Cell and Their Derived Exosomes in the Regulation of the Gut Microbiota in Inflammatory Bowel Disease.

Mesenchymal stem cells (MSCs) have shown great potential in the treatment of several inflammatory diseases due to their immunomodulatory ability, which is mediated by exosomes secreted by MSCs (MSC-Exs). The incidence of inflammatory bowel disease (IBD) is increasing globally, but there is currently no long-term effective treatment. As an emerging therapy, MSC-Exs have proven to be effective in alleviating IBD experimentally, and the specific mechanism continues to be explored. The gut microbiota plays an important role in the occurrence and development of IBD, and MSCs and MSC-Exs can effectively regulate gut microbiota in animal models of IBD, but the mechanism involved and whether the outcome can relieve the characteristic dysbiosis necessary to alleviate IBD still needs to be studied. This review provides current evidence on the effective modulation of the gut microbiota by MSC-Exs, offering a basis for further research on the pathogenic mechanism of IBD and MSC-Ex treatments through the improvement of gut microbiota.

Identification of master regulator genes controlling pathogenic CD4+ T cell fate in inflammatory bowel disease through transcriptional network analysis

Inflammatory bowel diseases (IBD) are a group of chronic inflammatory conditions of the gastrointestinal tract associated with multiple pathogenic factors, including dysregulation of the immune response. Effector CD4+ T cells and regulatory CD4+ T cells (Treg) are central players in maintaining the balance between tolerance and inflammation. Interestingly, genetic modifications in these cells have been implicated in regulating the commitment of specific phenotypes and immune functions. However, the transcriptional program controlling the pathogenic behavior of T helper cells in IBD progression is still unknown. In this study, we aimed to find master transcription regulators controlling the pathogenic behavior of effector CD4+ T cells upon gut inflammation. To achieve this goal, we used an animal model of IBD induced by the transfer of naïve CD4+ T cells into recombination-activating gene 1 (Rag1) deficient mice, which are devoid of lymphocytes. As a control, a group of Rag1−/− mice received the transfer of the whole CD4+ T cells population, which includes both effector T cells and Treg. When gut inflammation progressed, we isolated CD4+ T cells from the colonic lamina propria and spleen tissue, and performed bulk RNA-seq. We identified differentially up- and down-regulated genes by comparing samples from both experimental groups. We found 532 differentially expressed genes (DEGs) in the colon and 30 DEGs in the spleen, mostly related to Th1 response, leukocyte migration, and response to cytokines in lamina propria T-cells. We integrated these data into Gene Regulatory Networks to identify Master Regulators, identifying four up-regulated master gene regulators (Lef1, Dnmt1, Mybl2, and Jup) and only one down-regulated master regulator (Foxo3). The altered expression of master regulators observed in the transcriptomic analysis was confirmed by qRT-PCR analysis and found an up-regulation of Lef1 and Mybl2, but without differences on Dnmt1, Jup, and Foxo3. These two master regulators have been involved in T cells function and cell cycle progression, respectively. We identified two master regulator genes associated with the pathogenic behavior of effector CD4+ T cells in an animal model of IBD. These findings provide two new potential molecular targets for treating IBD.

Novel 5-HT7 receptor antagonists modulate intestinal immune responses and reduce severity of colitis.

Inflammatory bowel disease (IBD) encompasses several debilitating chronic gastrointestinal (GI) inflammatory disorders, including Crohn's disease and ulcerative colitis. In both conditions, mucosal inflammation is a key clinical presentation associated with altered serotonin (5-hydroxytryptamine or 5-HT) signaling. This altered 5-HT signaling is also found across various animal models of colitis. Of the 14 known receptor subtypes, 5-HT receptor type 7 (5-HT7) is one of the most recently discovered. We previously reported that blocking 5-HT signaling with either a selective 5-HT7 receptor antagonist (SB-269970) or genetic ablation alleviated intestinal inflammation in murine experimental models of colitis. Here, we developed novel antagonists, namely, MC-170073 and MC-230078, which target 5-HT7 receptors with high selectivity. We also investigated the in vivo efficacy of these antagonists in experimental colitis by using dextran sulfate sodium (DSS) and the transfer of CD4+CD45RBhigh T cells to induce intestinal inflammation. Inhibition of 5-HT7 receptor signaling with the antagonists, MC-170073 and MC-230078, ameliorated intestinal inflammation in both acute and chronic colitis models, which was accompanied by lower histopathological damage and diminished levels of proinflammatory cytokines compared with vehicle-treated controls. Together, the data reveal that the pharmacological inhibition of 5-HT7 receptors by these selective antagonists ameliorates the severity of colitis across various experimental models and may, in the future, serve as a potential treatment option for patients with IBD. In addition, these findings support that 5-HT7 is a viable therapeutic target for IBD.NEW & NOTEWORTHY This study demonstrates that the novel highly selective 5-HT7 receptor antagonists, MC-170073 and MC-230078, significantly alleviated the severity of colitis across models of experimental colitis. These findings suggest that inhibition of 5-HT7 receptor signaling by these new antagonists may serve as an alternative mode of treatment to diminish symptomology in those with inflammatory bowel disease.

Intestinal Barrier Protection by Probiotic Lactobacillus-Associated Indoles in Caco-2 and Enteroids

Gut bacteria generate from dietary tryptophan (trp) indole compounds, which act as potent signaling molecules intricately involved in the regulation of intestinal homeostasis and barrier integrity. Lactobacillus rhamnosus GG (LGG), a widely used probiotic, has demonstrated ability to restore the gut barrier in animal models of colitis and sepsis, as well as in children with irritable bowel syndrome. To investigate the hypothesis that LGG-derived indoles are responsible for its gut barrier-enhancing properties, we fed gnotobiotic mice trp-suffcient and trp-deficient diets. We then monocolonized them with LGG, using PBS gavaged mice as a control, and analyzed the ileal transcriptome by bulk RNA sequencing and both fecal and serum metabolomes by LC-MS. Using our novel bioinformatic tool METRCA, which correlates metabolites and gene networks, we uncovered an unexpected and substantial influence of indole spatial distribution on genes associated with gut integrity: some were significantly positively linked to tight junction (TJ) genes exclusively from the luminal side, some exclusively from the serum, and others from both. Specifically, we identified nine indoles—indole-acetamide (IAM), indole-carboxaldehyde (IAL), indole-3-lactic acid (ILA), indole-3-propionic acid (IPA), indole-3-acrylic acid (IAR), indole-3-carbinol (ICB), indole-acetic acid (IAA), indole-3-acetonitrile (IAN), and indole-3-carboxylic acid (ICA)—that demonstrated the potential to maintain gut barrier function. To assess their impact, we used a high-throughput system that measured permeability through transepithelial electrical resistance (TEER) and FITC-dextran (4 kDa) in polarized Caco-2 cells. By luminally challenging cells with Clostridium diffcile toxins (TOX), we induced barrier disruption to model leaky gut. Intriguingly, when applied luminally, IAA, IAN, ICA, and ILA rescued the TEER of Caco-2 cells exposed to TOX, while IAM, IAL, and ILA were effective when applied basolaterally, suggesting a strong polar component to their barrier repair capacity. FITC transport revealed a significant basolateral rescue effect of IAM and luminal rescue effect of IAA and ICA, indicating that different sets of indoles are required to repair the pore and leak pathways. Furthermore, we confirmed that basolateral IAM rescued FITC permeability and induced increased expression of TJ genes Tjp1 and Ocln in enteroids challenged with lipopolysaccharides. In summary, our research highlights the potential beneficial therapeutic application of certain indoles in repairing disrupted gut barriers. NIHR01-AT010243 (NG, RF), R01DK119198 (NG), NSF 1754783 (RF). This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Exploring the synergistic potential of probiotics and vitamin D to ameliorate acute TNBS-induced colitis in mice

Inflammatory Bowel Disease (IBD), either Crohn’s disease or Ulcerative Colitis, are diseases characterized by chronic inflammation of the gastrointestinal tract, disruption of mucosal barrier, gut dysbiosis and vitamin D deficiency. The use of probiotics or vitamin D supplements have been studied individually in different colitis models to determine their beneficial effects by increasing tight junction proteins such as occludin. However, the synergistic effects of combining these treatments to target tight junction expression are still unknown. Therefore, the objective of this research was to demonstrate the effcacy of probiotics and high dietary vitamin D to ameliorate colonic inflammation by increasing mucosal barrier integrity. We hypothesized that co-administration of a probiotic mixture with vitamin D would reduce colitis-induced inflammation by increasing tight junction expression. For the methodology, male and female C57BL/6 mice were divided into four treatment groups: Colitis+Vehicle (n=10), Colitis+Probiotic (n=10), Colitis+Vitamin D (n=11), Colitis+Probiotic+Vitamin D (n=7). Animals received seven days of pretreatment with Vivomixx probiotics in water, high vitamin D (5IU/g) in food, or both. On day 7, animals were anesthetized lightly, and colitis induction was done by intracolonic administration of 0.1mL of 4mg TNBS in 30% ethanol. Water, food, and body weight were monitored daily. Animals were sacrificed on day ten, the colonic tissue was removed and assessed for inflammation then stained for occludin expression by immunofluorescence, and probiotic colonization was confirmed within fecal samples by RT-PCR amplification of S. Thermophilus gene. Results indicate that all animals decreased weight after colitis induction, but only animals receiving probiotic had a slight recovery by day 10. Animals receiving the probiotic mixture had higher S. Thermophilus expression in fecal samples compared to vehicle (p&lt;0.001) indicating appropriate colonization. A significant reduction in macroscopic damage score (3.92 vs. 7.42, p&lt;0.05) and microscopic score (3.42 vs 7.20, p&lt;0.01) was found in animals with Probiotic+Vitamin D compared to vehicle. Although an increase in occludin expression was observed with probiotic administration it did not reach statistical significance. In conclusion, findings indicate a beneficial effect of combining probiotics and vitamin D on colonic tissue damage in an animal model of acute colitis but this did not impact the tight junction protein occludin. This work was supported by RISE (R25GM082406), G-RISE (T32GM144896), PRI MD Summer Program and Porter Physiology Development Fellowship. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

A water-soluble arabinoxylan from Chinese liquor distillers' grains: Structural characterization and anti-colitic properties

Chinese liquor distillers' grain (CLDG) is a valuable and abundant by-product from traditional Chinese baijiu production, containing a diverse array of bioactive components that have attracted significant interest. Herein, a water-soluble polysaccharide, DGPS-2B, with a weight-average molecular weight of 37.3 kDa, was isolated from the alkali-extract fraction of CLDG. Methylation and NMR analysis identified that the primary constituents of DGPS-2B are arabinoxylans, with an arabinose-to-xylose ratio of 0.66. In an animal model of colitis, DGPS-2B treatment significantly altered the gut microbiota composition by increasing the SCFA-producing bacteria (e.g., Butyricicoccus) and reducing the mucin-degrading bacteria such as Muribaculaceae. This microbial shift resulted in elevated production of butyrate, acetate, and propionate, which subsequently suppressed NF-κB signaling, decreased the levels of IL-1β, IL-6, and TNFα, and potentially inactivated Notch signaling. These multifaceted effects stimulated mucin 2 production, reduced inflammation and apoptosis in the gut epithelium, and ultimately alleviated colitis symptoms. Collectively, this study not only elucidates the purification and characterization of DGPS-2B from CLDG but also illuminates its anti-colitic properties and the underlying molecular mechanisms. These findings underscore the potential of DGPS-2B as a therapeutic intervention for managing inflammatory bowel disease and emphasize CLDG as a promising source for developing value-added products.

Leaky gut, circulating immune complexes, arthralgia, and arthritis in IBD: coincidence or inevitability?

Most host-microbiota interactions occur within the intestinal barrier, which is essential for separating the intestinal epithelium from toxins, microorganisms, and antigens in the gut lumen. Gut inflammation allows pathogenic bacteria to enter the blood stream, forming immune complexes which may deposit on organs. Despite increased circulating immune complexes (CICs) in patients with inflammatory bowel disease (IBD) and discussions among IBD experts regarding their potential pathogenic role in extra-intestinal manifestations, this phenomenon is overlooked because definitive evidence demonstrating CIC-induced extra-intestinal manifestations in IBD animal models is lacking. However, clinical observations of elevated CICs in newly diagnosed, untreated patients with IBD have reignited research into their potential pathogenic implications. Musculoskeletal symptoms are the most prevalent extra-intestinal IBD manifestations. CICs are pivotal in various arthritis forms, including reactive, rheumatoid, and Lyme arthritis and systemic lupus erythematosus. Research indicates that intestinal barrier restoration during the pre-phase of arthritis could inhibit arthritis development. In the absence of animal models supporting extra-intestinal IBD manifestations, this paper aims to comprehensively explore the relationship between CICs and arthritis onset via a multifaceted analysis to offer a fresh perspective for further investigation and provide novel insights into the interplay between CICs and arthritis development in IBD.

A single-agent fusion of human IL-2 and anti-IL-2 antibody that selectively expands regulatory T cells

The occurrence of many autoimmune diseases takes root on the disrupted balance among Treg cells, Teff cells, etc. Low-dose interleukin-2 (IL-2) cytokine demonstrates promising clinical efficacy in the expansion of Treg cells and the treatment of autoimmune diseases. However, its clinical application is hindered by the small therapeutic index and short half-life. Previous studies have shown that non-covalent complex of human IL-2 and anti-IL-2 antibody biases cytokine activity towards Treg cells and extends IL-2’s half-life. The clinical translation of such complex is non-trivial. In this study, we discover an anti-human IL-2 antibody and engineer a covalently-linked single-agent fusion of human IL-2 and its antibody that selectively expands Treg cells and exhibits superior disease control activity in animal models of ulcerative colitis and systemic lupus erythematosus, with proper safety profile and good developability. These studies pave the road for its clinical development in diverse autoimmune diseases.

A254 CANAGLIFLOZIN EXACERBATES CHEMICALLY INDUCED COLITIS WHEN COMBINED WITH A HIGH SUGAR DIET

Abstract Background Consumption of high-sugar diets exacerbates inflammation and hinders the healing process in animal models of acute colitis. Canagliflozin (CANA) is a sodium glucose cotransporter-2 (SGLT2) inhibitor primarily used for the management of type 2 diabetes and cardiovascular disease. CANA has demonstrated the ability to suppress human T cell and macrophage effector function and to improve inflammation in rat colitis models. Based on these findings, we hypothesized that CANA would mitigate the deleterious effects of a high sugar diet in a DSS colitis model through its effects on immune effector cells. Aims The aim of this study was to examine the effects of a high sugar diet and CANA administration on colonic inflammation in an animal model of acute colitis. Methods Adult wild-type male and female 129/SvEv mice were placed on standard chow or a high-sugar diet (HSD) containing 50% sucrose (AIN76A) ± CANA (10mg/kg) gavaged daily (n=4-6 for each group). Following three days on the respective diet, mice received 1.8-2% dextran sodium sulfate (DSS) in their drinking water for 5 days, followed by water alone for 4 days. Disease Activity Index (DAI) was computed daily based on changes in animal weight, stool consistency, and blood in stool. Colonic tissues were evaluated for histological changes, weight-to-length ratio, and cytokine levels using the MesoScale discovery platform. Results Mice on the HSD had increased severity of colitis compared with chow fed mice as evidenced by enhanced DAI, increased weight loss, and increased levels of colonic TNFα (pampersand:003C0.02). Response to CANA treatment was both sex and diet dependent. Contrary to our hypothesis, CANA treatment increased severity of colitis in male mice on the HSD as evidenced by increased DAI and delayed healing with increased enterocyte injury and increased levels of lamina propria neutrophils and lymphocytes. CANA treatment did not exacerbate disease severity in females on the HSD but did delay healing as evidenced by increased lamina propria neutrophils and lymphocytes and worse enterocyte injury. These effects were not observed in mice that were fed standard chow diets with CANA. Conclusions A high-sugar diet significantly exacerbates chemically induced colitis and delays healing. This effect is intensified when combined with CANA, especially in male mice. These findings indicate that effects of SGLT2 inhibitors on colonic inflammation can be modulated by both dietary intake and sex. Funding Agencies CCC

Therapeutic effects of epigallocatechin-3-gallate for inflammatory bowel disease: A preclinical meta-analysis

BackgroundEpigallocatechin-3-gallate (EGCG), the primary active compound in green tea, is recognized for its significant anti-inflammatory properties and potential pharmacological effects on inflammatory bowel disease (IBD). However, comprehensive preclinical evidence supporting the use of EGCG in treating IBD is currently insufficient. PurposeTo evaluate the efficacy of EGCG in animal models of IBD and explore potential underlying mechanisms, serving as a groundwork for future clinical investigations. MethodsA systematic review of pertinent preclinical studies published until September 1, 2023, in databases such as PubMed, Embase, Web of Science, and Cochrane Library was conducted, adhering to stringent quality criteria. The potential mechanisms via which EGCG may address IBD were summarized. STATA v16.0 was used to perform a meta-analysis to assess IBD pathology, inflammation, and indicators of oxidative stress. Additionally, dose-response analysis and machine learning models were utilized to evaluate the dose-effect relationship and determine the optimal dosage of EGCG for IBD treatment. ResultsThe analysis included 19 studies involving 309 animals. The findings suggest that EGCG can ameliorate IBD-related pathology in animals, with a reduction in inflammatory and oxidative stress indicators. These effects were observed through significant changes in histological scores, Disease Activity Index, Colitis Macroscopic Damage Index and colon length; a decrease in markers such as interleukin (IL)-1β, IL-6 and interferon-γ; and alterations in malondialdehyde, superoxide dismutase, glutathione, and catalase levels. Subgroup analysis indicated that the oral administration route of EGCG exhibited superior efficacy over other administration routes. Dose-response analysis and machine learning outcomes highlighted an optimal EGCG dosage range of 32–62 mg/kg/day, with an intervention duration of 4.8–13.6 days. ConclusionsEGCG exhibits positive effects on IBD, particularly when administered at the dose range of 32 – 62 mg/kg/day, primarily attributed to its ability to regulate inflammation and oxidative stress levels.

THE FUNCTION OF THE CYSTATHIONINE-GAMMA-LYASE/HYDROGEN SULFIDE AXIS IN THE PATHOGENESIS OF ULCERATIVE COLITIS

Abstract INTRODUCTION Current combination therapies in ulcerative colitis (UC) target different inflammatory cascades, including tumor necrosis factor-alpha (TNF-alpha) signaling. However, most patients do not achieve long-term remission, suggesting that the molecular pathophysiology of UC is still poorly understood. Endogenously produced hydrogen sulfide (H2S) has emerged as a critical physiological mediator of gastrointestinal homeostasis, limiting mucosal inflammation and promoting tissue healing in response to epithelial injury. Inhibition of cystathionine-gamma-lyase (CSE)-dependent H2S production in animal models of UC has been shown to exacerbate colitis and delay tissue repair. Our research group has strong evidence revealing that the CSE/H2S axis regulates TNF-alpha signaling in colonic epithelial cells. Therefore, we hypothesize that decreased CSE/H2S pathway activity in colonic mucosa cells leads to dysregulation of TNF-alpha signaling and uncontrolled inflammatory/immune responses with aberrant wound repair mechanisms contributing to the pathogenesis of UC. RESULTS We found a significant decrease in CSE mRNA and protein expression in colonic biopsies from patients with UC. Using a preclinical animal model of epithelium injury-induced chronic colitis (DSS), we confirmed a sustained downregulation of CSE, as well as upregulation of TNF-alpha and tumor necrosis receptor 2 expressions in colonic mucosa samples. Treatment with the slow-releasing H2S-donor GYY4137 significantly reduced the severity of DSS-induced inflammation and improved mucosal integrity and restitution responses. In epithelial cell and colonoid cultures, the inhibition of CSE-dependent H2S synthesis decreased the activation of extracellular-signal-regulated-kinase-1/2 (ERK1/2), increased IL-6 and TNF-alpha mRNA levels and suppressed basic and TNF-alpha–mediated colonocyte migration. CONCLUSION These studies demonstrate that CSE regulates mucosal TNF-alpha signaling, pro- and anti-inflammatory responses as well as colonic epithelial repair. Adding the H2S donor GYY4137 reduces inflammation, suggesting the restoration of normal TNF-alpha signaling function. Acknowledgments: KM is supported by the DoD Career Development Award (W81XWH2010641) and ACS Research Scholar Grant (RSG–21–027–01–CSM).

P082 Downregulated apelin expression in T cells in the setting of Chronic Colitis

Abstract Background APJ is a G protein-coupled receptor and was originally found as an orphan receptor. Isolation of apelin (APL) from the alimentary tract was found to be the endogenous ligand for APJ. It has been reported that APL is upregulated in the colonic tissues of a murine model of acute colitis induced by dextran sodium sulfate (DSS), and thus it may be suggested to be associated with the pathogenesis of inflammatory bowel diseases (IBD) in humans. However, the mechanism and function of APL in the context of IBD are still not understood. Here, we analyzed APL expression in an animal model of chronic colitis to define its function in the pathogenesis of IBD. Methods Each cell type in the colonic tissue, including epithelial cells and lamina propria lymphocytes, were first isolated from wild type C57BL6 mice (WT) to assess APL expression. Next, naïve T cells isolated from WT were adoptively transferred into Rag deficient mice (Rag-/-) to induce chronic colitis, and then APL expression was measured either in the colonic tissue or in the isolated splenic and colonic CD4+ T cells from these T cell-reconstituted Rag-/- to compare with those of WT or Rag-/- without colitis. In addition, WT naïve T cells were differentiated into either Th1, Th2 or Th17 in vitro to analyze APL expression. Finally, the Rag-/- receiving naïve T cells were administered a synthetic APL peptide, APL-13, to assess the severity of colitis. Results Semi-quantitative PCR (qPCR) revealed that CD4+ T cells express relatively higher level of APL compared to other cell types including the epithelial cells in colonic tissue from WT. However, APL expression in the colonic tissues from the Rag-/- induced chronic colitis was unexpectedly downregulated compared to control groups without colitis; this is not consistent with the previous report using acute DSS colitis model. Subsequently, qPCR revealed significantly decreased APL expression in the splenic and colonic T cells from Rag-/- induced colitis compared to that of WT. APL expressions in the effecter T cells in vivo and all of the differentiated T cells in vitro were also significantly downregulated compared to naïve T cells and non-differentiated control T cells, respectively. Given these results, APL-13 was injected into the Rag-/- that underwent T cell reconstitution to antagonize the APL downregulation. This resulted in reduced severity of colitis compared to that of vehicle control-injected group. Conclusion These results suggest that T cells can be one of the major sources of APL in colonic tissues, and APL downregulation in effecter T cells may lead to the development of chronic colitis. In addition, this study also suggests that APL may be a novel therapeutic target for IBD.