Dextran Sulfate Sodium Administration Research Articles

HOXD10 regulates intestinal permeability and inhibits inflammation of dextran sulfate sodium-induced ulcerative colitis through the inactivation of the Rho/ROCK/MMPs axis

Abstract Ulcerative colitis (UC) has been identified as a severe inflammatory disease with significantly increased incidence across the world. The detailed role and mechanism of HOXD10 in UC remain unclear. In present study, we found that HOXD10 was lowly expressed in UC samples and was notably decreased by dextran sulfate sodium (DSS) administration. Overexpression of HOXD10 dramatically ameliorated DSS-induced UC symptoms, including the loss of weight, increased disease activity index values, and the shortened colon length. Additionally, terminal-deoxynucleoitidyl transferase mediated nick end labeling and immunohistochemistry staining assays showed that HOXD10 overexpression suppressed cell apoptosis and facilitated proliferation of colon tissues after DSS treatment. Moreover, HOXD10 overexpression obviously suppressed DSS-triggered inflammatory response by decreasing the expression level of TNF-α, IL-6, and IL-1β. Furthermore, overexpression of HOXD10 effectively restored the intestinal permeability, thereby alleviating DSS-induced intestinal barrier dysfunction. Mechanistic study demonstrated that HOXD10 significantly reduced the activities of Rho/ROCK/MMPs axis in colon tissues of mice with UC. In conclusion, this study revealed that HOXD10 might effectively improve DSS-induced UC symptoms by suppressing the activation of Rho/ROCK/MMPs pathway.

NF-κB Inducing Kinase Attenuates Colorectal Cancer by Regulating Noncanonical NF-κB Mediated Colonic Epithelial Cell Regeneration

Dysregulated colonic epithelial cell (CEC) proliferation is a critical feature in the development of colorectal cancer. We show that NF-κB-inducing kinase (NIK) attenuates colorectal cancer through coordinating CEC regeneration/differentiation via noncanonical NF-κB signaling that is unique from canonical NF-κB signaling. Initial studies evaluated crypt morphology/functionality, organoid generation, transcriptome profiles, and the microbiome. Inflammation and inflammation-induced tumorigenesis was initiated in whole-body NIK knockout mice (Nik-/-)and conditional-knockout mice following administration of azoxymethane and dextran sulfate sodium (AOM/DSS). Human transcriptomic data revealed dysregulated noncanonical NF-κB signaling. In vitro studies evaluating Nik-/- crypts and organoids derived from mature, nondividing CECs and colonic stem cells (CSCs) exhibited increased accumulation and stunted growth, respectively. Transcriptomic analysis of Nik-/- cells revealed gene expression signatures associated with altered differentiation-regeneration. When assessed in vivo, Nik-/- mice exhibited more severe colitis with DSS administration and an altered microbiome characterized by increased colitogenic microbiota. In the inflammation-induced tumorigenesis model, we observed both increased tumor burdens and inflammation in mice where NIK is knocked out in CECs (NikΔCEC). Interestingly, this was not recapitulated when NIK was conditionally knocked out in myeloid cells (NikΔMYE). Surprisingly, conditional knockout of the canonical pathway in myeloid cells (RelAΔMYE) revealed decreased tumor burden and inflammation and no significant changes when conditionally knocked out in CECs (RelAΔCEC). Dysregulated noncanonical NF-κB signaling is associated with the development of colorectal cancer in a tissue dependent manner and defines a critical role for NIK in regulating gastrointestinal inflammation and regeneration associated with colorectal cancer.

Myeloid Cell-Derived IL-1 Signaling Damps Neuregulin-1 from Fibroblasts to Suppress Colitis-Induced Early Repair of the Intestinal Epithelium.

Neuregulin-1 (Nrg1, gene symbol: Nrg1), a ligand of the ErbB receptor family, promotes intestinal epithelial cell proliferation and repair. However, the dynamics and accurate derivation of Nrg1 expression during colitis remain unclear. By analyzing the public single-cell RNA-sequencing datasets and employing a dextran sulfate sodium (DSS)-induced colitis model, we investigated the cell source of Nrg1 expression and its potential regulator in the process of epithelial healing. Nrg1 was majorly expressed in stem-like fibroblasts arising early in mouse colon after DSS administration, and Nrg1-Erbb3 signaling was identified as a potential mediator of interaction between stem-like fibroblasts and colonic epithelial cells. During the ongoing colitis phase, a significant infiltration of macrophages and neutrophils secreting IL-1β emerged, accompanied by the rise in stem-like fibroblasts that co-expressed Nrg1 and IL-1 receptor 1. By stimulating intestinal or lung fibroblasts with IL-1β in the context of inflammation, we observed a downregulation of Nrg1 expression. Patients with inflammatory bowel disease also exhibited an increase in NRG1+IL1R1+ fibroblasts and an interaction of NRG1-ERBB between IL1R1+ fibroblasts and colonic epithelial cells. This study reveals a novel potential mechanism for mucosal healing after inflammation-induced epithelial injury, in which inflammatory myeloid cell-derived IL-1β suppresses the early regeneration of intestinal tissue by interfering with the secretion of reparative neuregulin-1 by stem-like fibroblasts.

Effects of Potential Prebiotics from Codium fragile on Intestinal Diseases

This study examined the effects of an extract of the green algae Codium fragile (hereafter referred to as CFE) on dextran sulfate sodium (DSS)-induced colitis. As the administration of CFE increased, the proliferation of Akkermansia muciniphila, which is a key player in metabolic and gastrointestinal disorders, also increased. After CFE administration for 10 weeks, acetic acid was identified as the major metabolite in mouse cecum and β-glucuronidase activity in mouse fecesdecreased. Further, CFE significantly alleviated the acute intestinal injury induced by DSS administration, including DAI score, colon length, and histological score. The experimental group also displayed indications of significantly lower neutrophil activity and inflammation. In conclusion, the protective effect of CFE against DSS colitis suggests its clinical use by IBD patients.

Sedanolide alleviates DSS-induced colitis by modulating the intestinal FXR-SMPD3 pathway in mice

IntroductionInflammatory bowel disease (IBD) is a global disease with limited therapy. It is reported that sedanolide exerts anti-oxidative and anti-inflammatory effects as a natural phthalide, but its effects on IBD remain unclear. ObjectivesIn this study, we investigated the impacts of sedanolide on dextran sodium sulfate (DSS)-induced colitis in mice. MethodsThe mice were administered sedanolide or vehicle followed by DSS administration, after which colitis symptoms, inflammation levels, and intestinal barrier function were evaluated. Transcriptome analysis, 16S rRNA sequencing, and targeted metabolomics analysis of bile acids and lipids were performed. ResultsSedanolide protected mice from DSS-induced colitis, suppressed the inflammation, restored the weakened epithelial barrier, and modified the gut microbiota by decreasing bile salt hydrolase (BSH)-expressing bacteria. The downregulation of BSH activity by sedanolide increased the ratio of conjugated/unconjugated bile acids (BAs), thereby inhibiting the intestinal farnesoid X receptor (FXR) pathway. The roles of the FXR pathway and gut microbiota were verified using an intestinal FXR-specific agonist (fexaramine) and germ-free mice, respectively. Furthermore, we identified the key effector ceramide, which is regulated by sphingomyelin phosphodiesterase 3 (SMPD3). The protective effects of ceramide (d18:1/16:0) against inflammation and the gut barrier were demonstrated in vitro using the human cell line Caco-2. ConclusionSedanolide could reshape the intestinal flora and influence BA composition, thus inhibiting the FXR-SMPD3 pathway to stimulate the synthesis of ceramide, which ultimately alleviated DSS-induced colitis in mice. Overall, our research revealed the protective effects of sedanolide against DSS-induced colitis in mice, which indicated that sedanolide may be a clinical treatment for colitis. Additionally, the key lipid ceramide (d18:1/16:0) was shown to mediate the protective effects of sedanolide, providing new insight into the associations between colitis and lipid metabolites.

Human umbilical cord/placenta mesenchymal stem cell conditioned medium attenuates intestinal fibrosis in vivo and in vitro

BackgroundA significant unmet need in inflammatory bowel disease is the lack of anti-fibrotic agents targeting intestinal fibrosis. This study aimed to investigate the anti-fibrogenic properties and mechanisms of the conditioned medium (CM) from human umbilical cord/placenta-derived mesenchymal stem cells (UC/PL-MSC-CM) in a murine intestinal fibrosis model and human primary intestinal myofibroblasts (HIMFs).MethodsUC/PL-MSC-CM was concentrated 15-fold using a 3 kDa cut-off filter. C57BL/6 mice aged 7 weeks old were randomly assigned to one of four groups: (1) control, (2) dextran sulfate sodium (DSS), (3) DSS + CM (late-phase treatment), and (4) DSS + CM (early-phase treatment). Chronic DSS colitis and intestinal fibrosis was induced by three cycles of DSS administration. One DSS cycle consisted of 7 days of oral DSS administration (1.75%, 2%, and 2.5% DSS), followed by 14 days of drinking water. UC/PL-MSC-CM was intraperitoneally administered in the late phase (from day 50, 10 times) or early phase (from day 29, 10 times) of DSS cycles. HIMFs were treated with TGF-β1 and co-treated with UC/PL-MSC-CM (10% of culture media) in the cellular model.ResultsIn the animal study, UC/PL-MSC-CM reduced submucosa/muscularis propria thickness and collagen deposition, which improved intestinal fibrosis in chronic DSS colitis. The UC/PL-MSC-CM significantly reduced the expressions of procollagen1A1 and α-smooth muscle actin, which DSS significantly elevated. The anti-fibrogenic effect was more apparent in the UC-MSC-CM or early-phase treatment model. The UC/PL-MSC-CM reduced procollagen1A1, fibronectin, and α-smooth muscle actin expression in HIMFs in the cellular model. The UC/PL-MSC-CM downregulated fibrogenesis by suppressing RhoA, MRTF-A, and SRF expression.ConclusionsHuman UC/PL-MSC-CM inhibits TGF-β1-induced fibrogenic activation in HIMFs by blocking the Rho/MRTF/SRF pathway and chronic DSS colitis-induced intestinal fibrosis. Thus, it may be regarded as a novel candidate for stem cell-based therapy of intestinal fibrosis.

An inhibitory immunoreceptor Allergin-1 regulates the intestinal dysbiosis and barrier function in mice.

The intestinal barrier consists of mucosal, epithelial, and immunological barriers and serves as a dynamic interface between the host and its environment. Disruption of the intestinal barrier integrity is a leading cause of various gastrointestinal diseases, such as inflammatory bowel disease. The homeostasis of the intestinal barrier is tightly regulated by crosstalk between gut microbes and the immune system; however, the implication of the immune system on the imbalance of gut microbes that disrupts barrier integrity remains to be fully elucidated. An inhibitory immunoglobulin-like receptor, Allergin-1, is expressed on mast cells and dendritic cells and inhibits Toll-like receptor (TLR)-2 and TLR-4 signaling in these cells. Since TLRs are major sensors of microbiota and are involved in local epithelial homeostasis, we investigated the role of Allergin-1 in maintaining intestinal homeostasis. Allergin-1-deficient (Milr1-/-) mice exhibited more severe dextran sulfate sodium (DSS)-induced colitis than did wild-type (WT) mice. Milr1-/- mice showed an enhanced intestinal permeability than did WT mice even before DSS administration. Treatment of Milr1-/- mice with neomycin, but not ampicillin, restored intestinal barrier integrity. The 16S rRNA gene sequencing analysis demonstrated that Bifidobacterium pseudolongum was the dominant bacteria in Milr1-/- mice after treatment with ampicillin. Although the transfer of B. pseudolongum to germ-free WT mice had no effect on intestinal permeability, its transfer into ampicillin-treated WT mice enhanced intestinal permeability. These results demonstrated that Allergin-1 deficiency enhanced intestinal dysbiosis with expanded B. pseudolongum, which contributes to intestinal barrier dysfunction in collaboration with neomycin-sensitive and ampicillin-resistant microbiota.

A4 DNA HYPOMETHYLATION INHIBITS COLITIS-ASSOCIATED CANCER

Abstract Background Colorectal cancer is the second leading cause of cancer death in Canada. A major risk factor for the development of colorectal cancer is chronic inflammation leading to colitis-associated cancer (CAC). We previously described a CAC mouse model in which tumors arise from DCLK1+ cells following loss of the tumor suppressor adenomatous polyposis coli (APC) and induction of colitis. Interestingly, both colitis and CAC are associated with DNA methylation changes that lead to altered gene expression. Moreover, inhibition of DNA methylation has recently been shown to lead to a viral mimicry response. The effects of DNA methylation on colonic tumorigenesis, however, is not known. Aims Thus, we aim to investigate whether inhibition of DNA methylation leads to a viral mimicry response that inhibits colitis-associated tumorigenesis. Methods We first examined the effects of DNA hypomethylation on CAC, by crossing Dclk1-CreERT2/Apcf/f mice to Dnmt1f/f mice which allowed for knock-out of the DNA methyltransferase enzyme DNMT1 in DCLK1+ cells. Dclk1/Apcf/f/Dnmt1f/f and Dclk1/Apcf/f (control group) mice were administered three doses of tamoxifen followed by 2.5% dextran sodium sulfate (DSS) for five days to induce colitis. Fourteen weeks later, we assessed colonic tumor number and size. In a separate cohort of Dclk1/Apcf/f mice treated with DSS, we compared colonic tumor number in mice treated with six doses of 5-AZA-2’-deoxycytidine (5-AZA) versus vehicle. The effects of 5-AZA and DSS on DNA methylation were assessed using the Infinium Mouse Methylation BeadChip Array on colonic epithelial cells isolated from mice treated with vehicle versus 5-AZA in the presence or absence of colitis. RNA expression of viral transposable elements and type I interferon response related genes were measured as a readout of a viral mimicry response. Lastly, we investigated the mechanism by which DNA hypomethylation affects tumorigenesis by crossing Dclk1/Apcf/f/Dnmt1f/f mice to MAVS knockout mice and examining tumor number following tamoxifen and DSS administration as above. Results Deletion of DNMT1 in DCLK1+ cells or treatment with 5-AZA significantly decreased colonic tumor number and size. Treatment with 5-AZA or DNMT1 loss led to DNA hypomethylation and subsequent upregulation of endogenous retroviral expression. Both 5-AZA treatment and DNMT1 knockout in DCLK1+ cells led to increased expression of type I interferon response genes. Knockout of the type I interferon response related gene, MAVS, reversed the anti-tumor effect observed with DNMT1 loss. Conclusions Our findings demonstrate that DNA hypomethylation by 5-AZA or loss of DNMT1 reduces colitis-associated tumorigenesis through activation of a viral mimicry response. Funding Agencies CAG, CIHRCancer Research Society, Canada Foundation for Innovation, Lawson Health Research Institute

A199 ALKAL2/ALK AXIS PROMOTE PERSISTENT VISCERAL PAIN

Abstract Background Long-lasting changes in neural pain circuits precipitate the transition from acute to chronic pain in patients living with inflammatory bowel diseases (IBDs). While significant improvement in IBD therapy has been made to reduce inflammation, a large subset of patients continues to suffer throughout quiescent phases of the disease. Peripheral and central mechanisms contribute to the transition from acute to chronic pain during clinical remission. In the search of new treatments, we previously found that targeting the anaplastic lymphoma kinase (ALK) receptor could have therapeutic value for persistent pain conditions. Aims Here we investigated whether ALKAL2 (ALK ligand) /ALK signaling axis regulates chronic visceral pain. Methods We used the post-inflammatory dextran sodium sulfate (DSS) mouse model of colitis as a well-established rodent model of chronic visceral pain, in which animals display increased VHS 5 weeks after DSS administration in the absence of inflammation as described in IBD patients. To assess the role of ALKAL2/ALK signalling in chronic visceral pain, we pharmacologically blocked ALK receptor using clinically available compound Lorlatinib in the postcolitis model. Moreover we genetically depleted ALKAL2 in gut-innervating nociceptors that express the heat sensitive transient receptor potential vanilloid type 1 (TRPV1) channel, using shRNA vectorized in cell type specific Adeno-associated Viruses. Results We showed that ALKAL2 expression was significatively enhanced in lumbosacral (LS) dorsal root ganglia (DRG) sensory neurons in the post-colitis model. In naïve mice, ALKAL2 administration induced visceral hypersensitivity in an ALK dependant manner. In addition, depletion of ALKAL2 in TRPV1 nociceptors or blocking ALK with the clinically available compound Lorlatinib, reversed visceral hypersensitivity in the post-colitis model. Accordingly, phosphorylation of ALK receptor occurring at the LS of the spinal dorsal horn was reduced. Conclusions Overall, these findings provide novel insights into the mechanisms underlying the transition from acute to chronic visceral pain in IBD. Our work could generate a portfolio of clinically available anti-cancer drugs, including Lorlatinib, as novel pain therapeutics. Repurposed ALK inhibitor could facilitate pain management in in individuals with IBD. Funding Agencies CIHR

Transient gestational hypothyroxinemia accelerates and enhances ulcerative colitis-like disorder in the male offspring.

Gestational hypothyroxinemia (HTX) is a condition that occurs frequently at the beginning of pregnancy, and it correlates with cognitive impairment, autism, and attentional deficit in the offspring. Evidence in animal models suggests that gestational HTX can increase the susceptibility of the offspring to develop strong inflammation in immune-mediated inflammatory diseases. Ulcerative colitis (UC) is a frequent inflammatory bowel disease with unknown causes. Therefore, the intensity of ulcerative colitis-like disorder (UCLD) and the cellular and molecular factors involved in proinflammatory or anti-inflammatory responses were analyzed in the offspring gestated in HTX (HTX-offspring) and compared with the offspring gestated in euthyroidism (Control-offspring). Gestational HTX was induced by the administration of 2-mercapto-1-methylimidazole in drinking water to pregnant mice during E10-E14. The HTX-offspring were induced with UCLD by the acute administration of dextran sodium sulfate (DSS). The score of UCLD symptomatology was registered every day, and colon histopathology, immune cells, and molecular factors involved in the inflammatory or anti-inflammatory response were analyzed on day 6 of DSS treatment. The HTX-offspring displayed earlier UCLD pathological symptoms compared with the Control-offspring. After 6 days of DSS treatment, the HTX-offspring almost doubled the score of the Control-offspring. The histopathological analyses of the colon samples showed signs of inflammation at the distal and medial colon for both the HTX-offspring and Control-offspring. However, significantly more inflammatory features were detected in the proximal colon of the HTX-offspring induced with UCLD compared with the Control-offspring induced with UCLD. Significantly reduced mRNA contents encoding for protective molecules like glutamate-cysteine ligase catalytic subunit (GCLC) and mucin-2 (MUC-2) were found in the colon of the HTX-offspring as compared with the Control-offspring. Higher percentages of Th17 lymphocytes were detected in the colon tissues of the HTX-offspring induced or not with UCLD as compared with the Control-offspring. Gestational HTX accelerates the onset and increases the intensity of UCLD in the offspring. The low expression of MUC-2 and GCLC together with high levels of Th17 Lymphocytes in the colon tissue suggests that the HTX-offspring has molecular and cellular features that favor inflammation and tissue damage. These results are important evidence to be aware of the impact of gestational HTX as a risk factor for UCLD development in offspring.

Effectiveness of probiotic- and fish oil-loaded water-in-oil-in-water (W1/O/W2) emulsions at alleviating ulcerative colitis.

Ulcerative colitis (UC) is a common chronic inflammatory disease that causes serious harm to human health. Probiotics have the effect of improving UC. This study evaluated the preventative potential of water-in-oil-in-water (W1/O/W2) emulsions containing both probiotics and fish oil on UC and associated anxiety-like behavior using a mice model. UC model was established in mice by administering dextran sulfate sodium salt (DSS). Free probiotics, probiotic-loaded emulsions, or fish oil and probiotic co-loaded emulsions were then orally administered to the mice. Various bioassays, histological studies, 16s rDNA gene sequencing, and behavioral experiments were conducted to assess changes in the intestinal environment, microbiota, and anxiety-like behavior of the mice. The fish oil and probiotic co-loaded emulsions significantly reduced the inflammatory response by enhancing tight junction protein secretion (ZO-1, Occludin, and Claudin-1), inhibiting pro-inflammatory factors (TNF-α, and IL-1β), and promoting short-chain fatty acids (SCFAs) production. These emulsions also modified the gut microbiota by promoting beneficial bacteria and suppressing pathogenic bacteria, thereby restoring a balanced gut microbiota. Notably, the emulsions containing both probiotics and fish oil also ameliorated anxiety-like behavior in the mice. The co-delivery of probiotics and fish oil using W1/O/W2 emulsions has shown significant promise in relieving UC and its associated anxiety-like behavior. These findings provide novel insights into the development of advanced therapeutic strategies for treating UC.

Monoclonal Antibody Against Mature Interleukin-18 Ameliorates Colitis in Mice and Improves Epithelial Barrier Function.

Antitumor necrosis factor (TNF)-α antibodies have improved the outcome of inflammatory bowel disease (IBD); but half of patients remain unresponsive to treatment. Interleukin-18 (IL-18) gene polymorphism is associated with resistance to anti-TNF-α antibodies, but therapies targeting IL-18 have not been clinically applied. Only the mature protein is biologically active, and we aimed to investigate whether specific inhibition of mature IL-18 using a monoclonal antibody (mAb) against a neoepitope of caspase-cleaved mature IL-18 could be an innovative treatment for IBD. The expression of precursor and mature IL-18 in patients with UC was examined. Colitis was induced in C57/BL6 mice by administering dextran sulfate sodium (DSS), followed by injection with anti-IL-18 neoepitope mAb. Colon tissues were collected and subjected to histological analysis, immunohistochemistry, immunoblotting, and quantitative polymerase chain reaction. Colon epithelial permeability and microbiota composition were analyzed. Mature IL-18 expression was elevated in colon tissues of patients with active ulcerative colitis. Administration of anti-IL-18 neoepitope mAb ameliorated acute and chronic DSS-induced colitis; reduced interferon-γ, TNF-α, and chemokine (CXC motif) ligand-2 production and epithelial cell permeability; promoted goblet cell function; and altered the intestinal microbiome composition. The suppressive effect of anti-IL-18 neoepitope mAb was superior to that of anti-whole IL-18 mAb. Furthermore, combination therapy with anti-TNF-α Ab suppressed acute and chronic colitis additively by suppressing cytokine expressions and reducing cell permeability by upregulating claudin1 and occludin expression. Anti-IL-18 neoepitope mAb ameliorates acute and chronic colitis, suggesting that this mAb will be an innovative therapeutic option for IBD.

Polystyrene nanobeads exacerbate chronic colitis in mice involving in oxidative stress and hepatic lipid metabolism

BackgroundNanoplastics (NPs) are omnipresent in our lives as a new type of pollution with a tiny size. It can enter organisms from the environment, accumulate in the body, and be passed down the food chain. Inflammatory bowel disease (IBD) is a nonspecific intestinal inflammatory disease that is recurrent and prevalent in the population. Given that the intestinal features of colitis may affect the behavior and toxicity of NPs, it is imperative to clarify the risk and toxicity mechanisms of NPs in colitis models.Methods and resultsIn this study, mice were subjected to three cycles of 5-day dextran sulfate sodium (DSS) exposures, with a break of 7 to 11 days between each cycle. After the first cycle of DSS exposure, the mice were fed gavagely with water containing 100 nm polystyrene nanobeads (PS-NPs, at concentrations of 1 mg/kg·BW, 5 mg/kg·BW and 25 mg/kg·BW, respectively) for 28 consecutive days. The results demonstrated that cyclic administration of DSS induced chronic inflammation in mice, while the standard drug “5-aminosalicylic acid (5-ASA)” treatment partially improved colitis manifestations. PS-NPs exacerbated intestinal inflammation in mice with chronic colitis by activating the MAPK signaling pathway. Furthermore, PS-NPs aggravated inflammation, oxidative stress, as well as hepatic lipid metabolism disturbance in the liver of mice with chronic colitis.ConclusionPS-NPs exacerbate intestinal inflammation and injury in mice with chronic colitis. This finding highlights chronically ill populations’ susceptibility to environmental hazards, which urgent more research and risk assessment studies.

Dihydromyricetin alleviates inflammatory bowel disease associated intestinal fibrosis by inducing autophagy through the PI3K/AKT/mTOR signaling pathway.

Intestinal fibrosis is a common complication of inflammatory bowel disease and is characterized by tissue stiffening and luminal narrowing. Dihydromyricetin (DHM) can alleviate liver fibrosis and renal interstitial fibrosis by inducing autophagy. However, whether DHM can alleviate intestinal fibrosis remains unclear. This study is aimed at evaluating the role and mechanism of action of DHM in inflammatory bowel disease-associated intestinal fibrosis. Mice were administered dextran sulfate sodium (DSS) in drinking water to induce inflammatory bowel disease-associated intestinal fibrosis. HE staining, qPCR, and Western blotting were used to analyze colon inflammation. Masson's trichrome staining, qPCR, Western blotting, and immunofluorescence staining were used to evaluate the severity of fibrosis. Transmission electron microscopy and Western blotting were used to assess the activation of autophagosomes. The human colonic fibroblast line CCD-18Co was cultured in the presence of TGF-β1 to develop a fibrotic phenotype. Immunofluorescence staining, Western blotting, and qPCR were used to assess the alteration of fibrosis markers and used to investigate whether DHM-induced autophagy was involved in the inactivation of CCD-18Co cells. Additionally, the role of the PI3K/AKT/mTOR pathway was investigated. DHM alleviated intestinal inflammation and inhibited the progression of intestinal fibrosis. Additionally, DHM induced the activation of autophagy, thereby alleviating intestinal fibrosis, and downregulated the PI3K/AKT/mTOR signaling pathway in vitro. Overall, this study demonstrated that DHM can inhibit the progression of intestinal fibrosis and activation of colonic fibroblasts by inducing autophagy through the PI3K/AKT/mTOR signaling pathway, thereby playing a preventive and therapeutic role in intestinal fibrosis.

GPR15 in colon cancer development and anti-tumor immune responses

IntroductionThe chemoattractant receptor, G protein-coupled receptor 15 (GPR15), promotes colon homing of T cells in health and colitis. GPR15 function in colon cancer is largely unexplored, motivating our current studies.MethodsIn human study, immune cells were isolated from tumor tissues and healthy surgical tumor margins (STM), and their proportions as well as expression of GPR15 was analyzed by flow cytometry. In mouse studies, colon cancer was induced in GPR15-deficient (KO) and GPR15-suficient (Het) mice using azoxymethane (AOM) and dextran sulfate sodium (DSS) solution in drinking water. Serial endoscopy was performed in mice to monitor and visualize the distal region of colon. Mice were euthanized 10 weeks after the initial DSS administration, and the colon length and the number of polyps were recorded. Next, we identified the effects of GPR15L on established tumors in the MC38-colorectal cancer (CRC) mouse model. Immune cells were isolated from the mice colons or tumors and assessed by flow cytometry.ResultsOur analysis of human CRC tissue revealed a significant reduction in GPR15+ immune cell frequencies in tumors compared to ‘tumor-free’ surgical margins. Similarly, our data analysis using The Cancer Genome Atlas (TCGA) indicated that lower GPR15 expression is associated with poor survival in human colon cancer. In the AOM/DSS colitis-associated colon cancer model, we observed increased colonic polyps and lower survival in Gpr15+-KO compared to Gpr15-Het mice. Analysis of immune cell infiltrates in the colonic polyps showed significantly decreased CD8+ T cells and increased IL-17+ CD4+ and IL-17+ CD8+ T cells in Gpr15-KO than in Het mice. Consistent with a protective role of GPR15, administration of GPR15L to established tumors in the MC38-CRC model increased CD45+ cell infiltration, enhanced TNFa expression on CD4+ and CD8+ T cells at the tumor site and dramatically reduced tumor burden.DiscussionOur findings highlight an important, unidentified role of the GPR15-GPR15L axis in promoting a tumor-suppressive immune microenvironment and unveils a novel, colon-specific therapeutic target for CRC.

Therapeutic potential of a synthetic dual JAK1/TYK2 inhibitor in inflammatory bowel disease

Inflammatory bowel disease (IBD) is a chronic and incurable disease with an increasing incidence rate and low mortality rate. Selectively inhibiting JAK1 and TYK2 has been proposed as a strategy to enhance the efficacy of such inhibitors while minimizing the potential side effects on other JAK isoforms. Our previous studies identified small molecule 18 as a JAK1/TYK2 inhibitor with high selectivity and a new structure. Specifically, the IC50 of 18 at the kinase level reached 39 nM and 21 nM for JAK1 and TYK2, respectively, with 10-fold selectivity over both JAK2 and JAK3. In in vitro studies, 18 dose-dependently inhibited cytokine-induced STAT phosphorylation downstream of the JAK1 and TYK2 signaling pathway. In pharmacokinetic experiments, 18 demonstrated an oral bioavailability of 59.82%, making it a promising candidate for further in vivo studies. Using two mouse models of acute ulcerative colitis (UC) induced by the administration of dextran sulfate sodium (DSS) or oxazolone (OXA), 18 dose-dependently showed a better therapeutic effect than the positive control drug tofacitinib. Additionally, after long-term administration for 32 days, 18 displayed low toxicity to mice and a high safety profile. Taken together, these findings suggest that 18 is a JAK1/TYK2 dual inhibitor with therapeutic effects superior to those of tofacitinib in the treatment of IBD. Moreover, 18 is also a suitable clinical candidate for further investigation in diseases with strong involvement from interferon and/or IL-12/IL-23 in their pathogenesis. This study confirmed the therapeutic effect and long-term safety of inhibiting JAK1 and TYK2 to treat IBD.

Therapeutic Effects of Zymomonas mobilis on Experimental DSS-Induced Colitis Mouse Model.

Zymomonas mobilis, a Gram-negative bacteria observed in some popular beverages, is considered safe and has been studied for its potential therapeutic benefits. In this study, we explored its effects on the inflammatory process, tissue integrity, differential gene expression, and microbiota composition in an experimental dextran sulfate sodium (DSS)-induced colitis model in mice. As a result, Z. mobilis alleviated the symptoms caused by DSS administration, as indicated by reduced weight loss, disease activity index, a significant reduction in the colon weight/length ratio, and histopathological improvement. Also, Z. mobilis could restore the mucosal barrier as well as increase the expression of Muc3 and Ocln genes. An analysis of 16S rRNA sequences showed that Z. mobilis alters gut microbiota, increasing Akkermansia muciniphila abundance and decreasing Escherichia coli. Furthermore, Z. mobilis seems to be involved in potentiating a regulatory phenotype by inducing immunomodulatory genes like Tgfb, Il5, Il10, and Foxp3 and reducing the relative mRNA expression of proinflammatory cytokines TNF, Il6, and Il17. Our data suggest that Z. mobilis could alleviate disease progression and be considered a possible probiotic adjuvant for pathologies of the bowel.

Inflammatory Bowel Disease Increases the Severity of Myocardial Infarction after Acute Ischemia-Reperfusion Injury in Mice.

(1) Background: Increased risk of myocardial infarction (MI) has been linked to several inflammatory conditions, including inflammatory bowel disease (IBD). However, the relationship between IBD and MI remains unclear. Here, we implemented an original mouse model combining IBD and MI to determine IBD's impact on MI severity and the link between the two diseases. (2) Methods: An IBD model was established by dextran sulfate sodium (DSS) administration in drinking water, alone or with oral C. albicans (Ca) gavage. IBD severity was assessed by clinical/histological scores and intestinal/systemic inflammatory biomarker measurement. Mice were subjected to myocardial ischemia-reperfusion (IR), and MI severity was assessed by quantifying infarct size (IS) and serum cardiac troponin I (cTnI) levels. (3) Results: IBD mice exhibited elevated fecal lipocalin 2 (Lcn2) and IL-6 levels. DSS mice exhibited almost two-fold increase in IS compared to controls, with serum cTnI levels strongly correlated with IS. Ca inoculation tended to worsen DSS-induced systemic inflammation and IR injury, an observation which is not statistically significant. (4) Conclusions: This is the first proof-of-concept study demonstrating the impact of IBD on MI severity and suggesting mechanistic aspects involved in the IBD-MI connection. Our findings could pave the way for MI therapeutic approaches based on identified IBD-induced inflammatory mediators.

Fermented rice bran supplementation attenuates colonic injury through modulating intestinal aryl hydrocarbon receptor and innate lymphoid cells in mice with dextran sodium sulfate-induced acute colitis

This study investigated the effects of fermented rice bran (FRB) on modulating intestinal aryl hydrocarbon receptor (AhR) expression, innate lymphoid cell (ILC)3 populations, the fecal microbiota distribution, and their associations with dextran sodium sulfate (DSS)-induced acute colitis. C57BL/6 mice were assigned to four groups: 1) NC group, normal mice fed the AIN-93M diet; 2) FRB group, normal mice fed a diet supplemented with 5% FRB; 3) NCD group, DSS-treated mice fed AIN-93M; 4) FRBD group, DSS-treated mice fed a 5% FRB-supplemented diet. DSS was administered for 5 d and followed by 5 d for recovery. At the end of the experiment, mice were sacrificed. Their blood and intestinal tissues were collected. Results showed that there were no differences in colonic biological parameters and function between the NC and FRB groups. Similar fecal microbiota diversity was noted between these two groups. Compared to the non-DSS-treated groups, DSS administration led to increased intestinal permeability, enhanced inflammatory cytokine production and disease severity, whereas tight junctions and AhR, interleukin (IL)-22 expressions were downregulated, and the ILC3 population had decreased. Also, gut microbiota diversity differs from the non-DSS-treated groups and more detrimental bacterial populations exist when compared to the FRBD group. FRB supplementation in DSS-treated mice attenuated fecal microbial dysbiosis, decreased intestinal permeability, improved the barrier integrity, upregulated AhR and IL-22 expression, maintained the ILC3 population, and pathologically mitigated colonic injury. These findings suggest enhanced ILC3- and AhR-mediated functions may be partly responsible for the anti-colitis effects of FRB supplementation in DSS-induced colitis.

In vitro antibacterial effects of Broussonetia papyrifera leaf extract and its anti-colitis in DSS-treated mice.

Recently, the hybrid Broussonetia papyrifera (BP) has been extensively cultivated and predominantly utilized in ruminants because of its high protein and bioactive compound content. In the present study, the effects of an ethanolic extract of BP leaves (BPE, 200 mg/kg) on mitigating 2% dextran sodium sulfate (DSS)-induced intestinal inflammation in mice were evaluated. BPE is rich in flavonoids, polyphenols, and polysaccharides, and displays potent antioxidant and antibacterial activities against pathogenic strains such as Clostridium perfringens, Salmonella Typhimurium, and Salmonella enterica subsp. enterica in vitro. In a mouse study, oral administration of DSS resulted in weight loss, incidence of diarrhea, enlargement of the liver and spleen, impaired colonic morphology, downregulation of both gene and protein expression related to intestinal antioxidant (Nrf2) and barrier function (ZO-1), decreased diversity of colonic microbiota, and 218 differentially altered colonic metabolites; however, co-treatment with BPE did not restore these modified aspects except for the liver index and colonic bacterial diversity. The singular treatment with BPE did not manifest evident side effects in normal mice but induced a mild occurrence of diarrhea and a notable alteration in the colonic metabolite profile. Moreover, a single BPE administration augmented the abundance of the commensal beneficial bacteria Faecalibaculum and Akkermansia genera. Overall, the extract of BP leaves did not demonstrate the anticipated effectiveness in alleviating DSS-induced intestinal inflammation.