Severity Of Colitis In Mice Research Articles

Effect of Bacillus clausii in attenuating symptoms of DSS-induced ulcerative colitis by modulating NFkB pathway and oxidative stress in mice.

Ulcerative colitis (UC) is a condition characterized by inflammation and ulcer formation in the colon and rectum due to genetic and environmental factors. It is a common condition, with a global prevalence rate exceeding 0.3%. Current treatments have limited efficacy and can cause unwanted side effects, leading to a high recurrence rate and reduced quality of life for patients. This study suggests that Bacillus clausii has a beneficial role in reducing intestinal inflammation and relieving colitis symptoms in mice. The study aimed to examine B. clausii's potential to reduce the progression and pathogenesis of dextran sulphate sodium (DSS)-induced UC. Bacillus clausii was administered to mice as a pre-treatment, post-treatment and adjunct treatment with sulfasalazine for 14 days. The study found that B. clausii effectively reduced the severity of colitis in mice when used preventatively. Administering B. clausii after the onset of colitis also effectively alleviated symptoms. Combining B. clausii with standard sulfasalazine as adjunct therapy was more effective in reducing intestinal inflammation than using a single therapy alone. B. clausii has shown the potential to prevent colon damage and decrease the likelihood and severity of the disease. Immunohistochemistry results revealed a decrease in the expression of pro-inflammatory cytokines such as IL-1β, TNF-α and NFkB in colon tissue. Additionally, mice that received B. clausii showed a significant increase in anti-oxidant levels and improved haematological markers. In conclusion, it must be emphasized that B. clausii possesses the potential to alleviate the symptoms of UC.

Brief Disruption of Circadian Rhythms Alters Intestinal Barrier Integrity and Modulates DSS-Induced Colitis Severity in Mice.

Physiological processes in organisms exhibit circadian rhythms that optimize fitness and anticipate environmental changes. Luminal signals such as food or metabolites synchronize bowel activity, and disruptions in these rhythms are linked to metabolic disorders and gastrointestinal inflammation. To characterize the intrinsic intestinal rhythms and assess disruptions due to continuous darkness or light exposure, C57BL/6 mice were exposed to standard light-dark conditions or continuous light/darkness for 48h, with evaluations at four timepoints. We assessed intestinal morphology, mucus production, nitric oxide levels and permeability. Under standard light: dark cycles, mice showed changes in intestinal morphology consistent with normal tract physiology. Continuous light exposure caused marked alterations in the small intestine´s epithelium and lamina propria, reduced nitric oxide production in the colon, and predominant neutral mucins. Enhanced permeability was indicated by higher FITC-dextran uptake and increased frequency of IgG-coated bacteria. Additionally, the 48h-disruption influenced DSS-induced colitis with attenuation in L:L group, or exacerbation in D:D group, of clinical signs. These findings highlight the critical role of circadian rhythms in gut histoarchitecture and function, demonstrating that short-term disruptions in light-dark cycles can compromise intestinal barrier integrity and impact inflammatory outcomes.

TIPE2 aggravates experimental colitis and disrupts intestinal epithelial barrier integrity by activating JAK2/STAT3/SOCS3 signal pathway

Ulcerative colitis (UC) is a chronic relapsing and progressive inflammatory disease of the colon. TIPE2 is a negative regulator of innate and adaptive immunity that maintains immune homeostasis. We found that TIPE2 was highly expressed in mucosa of mice with colitis. However, the role of TIPE2 in colitis remains unclear. We induced colitis in mice with dextran sulphate sodium (DSS) and treated them with TIPE2, and investigated the inflammatory activity of the colon in vivo by cytokines detection and histopathological analyses. We also measured inflammatory alteration and tight junctions induced by DSS in vitro. The results demonstrated that administration of TIPE2 promoted the severity of colitis in mice and human colon epithelial cells. Furthermore, TIPE2 aggravated intestinal epithelial barrier dysfunction by decreasing the expression of the tight junction proteins Occludin, Claudin-1 and ZO-1. In addition, TIPE2 exacerbated intestinal inflammatory response by inhibiting the expression of SOCS3, remarkably activating JAK2/STAT3 signaling pathway, and increasing the translocation of phosphorylated STAT3 into the nucleus. Silencing of Tipe2 attenuated the DSS-induced activation of JAK2/STAT3, thereby rescuing epithelial inflammatory injury and restoring barrier dysfunction. These results indicate that TIPE2 augments experimental colitis and disrupted the integrity of the intestinal epithelial barrier by activating the JAK2/STAT3/SOCS3 signaling pathway.

Amlexanox targeted inhibition of TBK1 regulates immune cell function to exacerbate DSS-induced inflammatory bowel disease.

Amlexanox (ALX) is a small molecule drug for the treatment of inflammatory, autoimmune, metabolic and tumor diseases. At present, there are no studies on whether ALX has a therapeutic effect on inflammatory bowel disease (IBD). In this study, we used a mouse model of dextran sulfate sodium (DSS)-induced colitis to investigate the effect of ALX targeted inhibition of TBK1 on colitis. We found that the severity of colitis in mice was correlated with TBK1 expression. Notably, although ALX inhibited the activation of the TBK1-NF-κB/TBK1-IRF3 pro-inflammatory signaling pathway, it exacerbated colitis and reduced survival in mice. The results of drug safety experiments ruled out a relationship between this exacerbating effect and drug toxicity. In addition, ELISA results showed that ALX promoted the secretion of IL-1β and IFN-α, and inhibited the production of cytokines IL-6, TNF-α, IL-10, TGF-β and secretory IgA. Flow cytometry results further showed that ALX promoted T cell proliferation, activation and differentiation, and thus played a pro-inflammatory role; Also, ALX inhibited the generation of dendritic cells and the polarization of macrophages to M1 type, thus exerting anti-inflammatory effect. These data suggest that the regulation of ALX on the function of different immune cells is different, so the effect on the inflammatory response is bidirectional. In conclusion, our study demonstrates that simply inhibiting TBK1 in all immune cells is not effective for the treatment of colitis. Further investigation the anti-inflammatory mechanism of ALX on dendritic cells and macrophages may provide a new strategy for the treatment of IBD.

E4BP4 in macrophages induces an anti-inflammatory phenotype that ameliorates the severity of colitis

Macrophages are versatile cells of the innate immune system that work by altering their pro- or anti-inflammatory features. Their dysregulation leads to inflammatory disorders such as inflammatory bowel disease. We show that macrophage-specific upregulation of the clock output gene and transcription factor E4BP4 reduces the severity of colitis in mice. RNA-sequencing and single-cell analyses of macrophages revealed that increased expression of E4BP4 leads to an overall increase in expression of anti-inflammatory genes including Il4ra with a concomitant reduction in pro-inflammatory gene expression. In contrast, knockout of E4BP4 in macrophages leads to increased proinflammatory gene expression and decreased expression of anti-inflammatory genes. ChIP-seq and ATAC-seq analyses further identified Il4ra as a target of E4BP4, which drives anti-inflammatory polarization in macrophages. Together, these results reveal a critical role for E4BP4 in regulating macrophage inflammatory phenotypes and resolving inflammatory bowel diseases.

BACTERIAL SPHINGOLIPIDS EXACERBATE COLITIS BY INHIBITING ILC3-DERIVED IL-22 PRODUCTION

Abstract Commensal bacteria of the Bacteroidetes phylum are the primary producers of sphingolipids in the gut lumen. These lipids serve dual roles as bacterial virulence factors and regulators of the host mucosal immune system, including regulatory T cells and invariant natural killer T cells (iNKT). Sphingolipid composition is significantly altered in fecal samples of patients with inflammatory bowel disease (IBD). However, the specific mechanisms by which bacterial sphingolipids modulate mucosal homeostasis and regulate intestinal inflammation remain unclear. In this study, we investigated the impact of bacterial sphingolipids on intestinal inflammation by mono-colonizing mice with Bacteroides fragilis strains that either express or lack sphingolipids during DSS-induced colitis. We discovered that B. fragilis sphingolipids exacerbate intestinal inflammation. Mice mono-colonized with B. fragilis lacking sphingolipids exhibited less severe DSS-induced colitis. This amelioration of colitis was associated with increased production of interleukin-22 (IL-22) by innate lymphoid cell type 3 (ILC3). Consistent with the inhibitory effect of sphingolipids on IL-22 production, mice colonized with B. fragilis lacking sphingolipids showed enhanced epithelial STAT3 activity, intestinal cell proliferation, and antimicrobial peptide production following DSS treatment compared to those colonized with B. fragilis producing sphingolipids. Additionally, colitis severity in mice colonized with B. fragilis lacking sphingolipids was exacerbated upon IL-22 blockade. Furthermore, our study reveals that bacterial sphingolipids restrict epithelial IL-18 production following DSS treatment and interfere with IL-22 production by a subset of ILC3 cells expressing both the interleukin-18 receptor (IL-18R) and major histocompatibility complex class II (MHC II). These findings indicate that B. fragilis-derived sphingolipids exacerbate mucosal inflammation by impeding epithelial IL-18 expression, resulting in compromised production of IL-22 by ILC3 cells. Work Model

Minocycline synergizes with corticosteroids in reducing colitis severity in mice via the modulation of pro-inflammatory molecules.

Background: A few studies have highlighted the anti-inflammatory properties of minocycline in reducing colitis severity in mice, but its molecular mechanism is not fully understood. The aim of this study was to determine the anti-inflammatory properties of minocycline and the expression/activity profiles of molecules involved in pro-inflammatory signaling cascades, cytokines, and molecules involved in the apoptotic machinery. The synergistic effect between minocycline and corticosteroids was also evaluated. Methods: The effects of various treatment approaches were determined in mice using the dextran sulfate sodium (DSS) colitis model at gross and microscopic levels. The expression/activity profiles of various pro- or anti-inflammatory molecules were determined using Western blotting and polymerase chain reaction (PCR). Results: Minocycline treatment significantly reduced colitis severity using prophylactic and treatment approaches and produced a synergistic effect with budesonide and methylprednisolone in reducing the active state of colitis. This was mediated in part through reduced colonic expression/activity of pro-inflammatory molecules, cytokines, proteins involved in the apoptotic machinery, and increased expression of the anti-inflammatory cytokine IL-10. Conclusion: Minocycline synergizes with corticosteroids to reduce colitis severity, which could reduce their dose-dependent side effects and treatment cost. The reduction in colitis severity was achieved by modulating the expression/activity profiles of various pro- and anti-inflammatory signaling molecules, cytokines, and molecules involved in the apoptotic machinery.

Effect of minocycline, methyl prednisolone, or combination treatment on the colonic bacterial population in a state of colonic inflammation using the murine dextran sulfate sodium model

BackgroundSeveral reports demonstrated anti-inflammatory properties of minocycline in various inflammatory disorders including colitis. We have experimental evidence suggesting synergistic anti-inflammatory effect of minocycline with methyl prednisolone in reducing colitis severity in mice, but if this effect is in part related to modulating the composition of colonic microbiota is still unknown.Methodsthe effect of vehicle (V), minocycline (M), methyl prednisolone (MP), or combination (C) regimen on the composition of the microbiota of mice in a state of colon inflammation compared to untreated (UT) healthy mice was determined using 16s metagenomic sequencing, and the taxonomic and functional profiles were summarized.ResultsOverall, the bacterial flora from the phylum Firmicutes followed by Bacteroidota were found to be predominant in all the samples. However, the composition of Firmicutes was decreased relatively in all the treatment groups compared to UT group. A relatively higher percentage of Actinobacteriota was observed in the samples from the C group. At the genus level, Muribaculaceae, Bacteroides, Bifidobacterium, and Lactobacillus were found to be predominant in the samples treated with both drugs (C). Whereas “Lachnospiraceae NK4A136 group” and Helicobacter in the M group, and Helicobacter in the MP group were found to be predominant. But, in the UT group, Weissella and Staphylococcus were found to be predominant. Eubacterium siraeum group, Clostridia vadinBB60 group, Erysipelatoclostridium and Anaeroplasma genera were identified to have a significant (FDR p < 0.05) differential abundance in V compared to C and UT groups. While at the species level, the abundance of Helicobacter mastomyrinus, Massiliomicrobiota timonensis and uncultured Anaeroplasma were identified as significantly low in UT, C, and M compared to V group. Functional categories related to amino acid, carbohydrate, and energy metabolism, cell motility and cell cycle control were dominated overall across all the samples. Methane metabolism was identified as an enriched pathway. For the C group, “Colitis (decrease)” was among the significant (p = 1.81E-6) associations based on the host-intrinsic taxon set.ConclusionCombination regimen of minocycline plus methyl prednisolone produces a synergistic anti-inflammatory effect which is part related to alternation in the colonic microbiota composition.

The Transcription Factor RXRα in CD11c+ APCs Regulates Intestinal Immune Homeostasis and Inflammation.

APCs such as dendritic cells and macrophages play a pivotal role in mediating immune tolerance and restoring intestinal immune homeostasis by limiting inflammatory responses against commensal bacteria. However, cell-intrinsic molecular regulators critical for programming intestinal APCs to a regulatory state rather than an inflammatory state are unknown. In this study, we report that the transcription factor retinoid X receptor α (RXRα) signaling in CD11c+ APCs is essential for suppressing intestinal inflammation by imparting an anti-inflammatory phenotype. Using a mouse model of ulcerative colitis, we demonstrated that targeted deletion of RXRα in CD11c+ APCs in mice resulted in the loss of T cell homeostasis with enhanced intestinal inflammation and increased histopathological severity of colonic tissue. This was due to the increased production of proinflammatory cytokines that drive Th1/Th17 responses and decreased expression of immune-regulatory factors that promote regulatory T cell differentiation in the colon. Consistent with these findings, pharmacological activation of the RXRα pathway alleviated colitis severity in mice by suppressing the expression of inflammatory cytokines and limiting Th1/Th17 cell differentiation. These findings identify an essential role for RXRα in APCs in regulating intestinal immune homeostasis and inflammation. Thus, manipulating the RXRα pathway could provide novel opportunities for enhancing regulatory responses and dampening colonic inflammation.

Evaluation of microbial and vancomycin treatments in ulcerative colitis in murine models.

Despite the number of available therapies for ulcerative colitis (UC), severe side effects and high cost has limited their clinical application. Thus, finding new alternative strategies with minimal side effects is inevitable. Therefore, this study aimed to compare the effectiveness of different therapeutic approaches in DSS-induced colitis. Firstly, we designed oral bio-therapeutic products, Live Bacterial Products (LBP), which include a mixture of fecal bacteria strains isolated from healthy mice and prepared by microencapsulation and freeze-dried techniques. Then we investigated the efficiency of 7 days of freeze-dried FMT, LBP, and vancomycin treatments in DSS-induced colitis. Secondly, we compared the effect of 15 days of microbial therapies (freeze-dried powder of FMT and LBP microcapsules) and seven days of oral vancomycin on the severity of colitis in mice. Furthermore, the levels of IL-1β and TNF-α were measured in serum by ELISA, and the fecal microbiota diversity was analyzed by high-throughput sequencing for all mice groups. After seven days of treatments, our results indicated that oral vancomycin reduced the severity of DSS-induced colitis in mice, where weight gain and a decrease in IL-1 β and TNF-α levels were observed in the vancomycin group compared with other treatment groups. While after two weeks of treatment, the LBP microcapsules were able to reduce the severity of colitis. And at the end of the treatment period, weight gain and a decrease in the DAI scores and the levels of IL-1β and TNF-α were noted in the LBP treatment group compared to other treatment groups. By high-throughput sequencing of the 16S rRNA gene, our results showed that while the microcapsules LBP treatment increased the fecal microbial diversity, after vancomycin therapy, most of the fecal microbiota genera and operational taxonomic units (OTUs) were depleted. Our results concluded that treatment duration and preparation methods affect the microbial therapies' efficiency in UC. Furthermore, this study highlighted the negative consequences of oral vancomycin administration on gut health that should be known before using this medication.

Prevention of dextran sulfate sodium (DSS)-induced ulcerative colitis in mice by a synbiotic approach using probiotic and lactulose.

In this research, the synbiotic effects of probiotic Lactiplantibacillus plantarum YW11 and lactulose on intestinal morphology, colon function and immune activity were evaluated in a mouse model of UC induced by dextran sulfate sodium (DSS). The results revealed that L. plantarum YW11 in combination with lactulose decreased the severity of colitis in mice and improved the structure of the colon damaged, as assessed using colon length and disease condition. Moreover, colonic levels of pro-inflammatory cytokines (IL-1β, IL-6, IL-12, TNF-α and IFN-γ) were significantly lower and anti-inflammatory factors (IL-10) were significantly higher following the synbiotic supplementation. The synbiotic also exerted antioxidant effects by up-regulating SOD and CAT levels and down-regulating MDA levels in colon tissue. It could also reduce the relative expression of iNOS mRNA and increase the relative expression of nNOS and eNOS mRNA. Western Blot confirmed the increased expression of c-Kit, IκBα and SCF, and significantly reduced expression of NF-κB protein. Therefore, combination of L. plantarum YW11 and lactulose exerted therapeutic effects mainly through the NF-κB anti-inflammatory pathway, which represented a novel synbiotic approach in the prevention of colonic inflammation.

Bacteroides vulgatusattenuates colitis by inhibiting CD82 and increasing activation of the NLRP3 inflammasome

Abstract Inflammatory bowel disease (IBD), involving Crohn’s disease (CD) and ulcerative colitis (UC), is a worldwide disease. IBD is known as a chronic immune-mediated intestinal inflammation caused by a variety of causes, such as genetic, microbial and environmental factors, but the exact etiology and treatment are unclear and undiscovered. Although the correlation between IBD and gut microbiota dysbiosis has not been fully demonstrated, it has long been hypothesized that changes in the microbiome are responsible for IBD. Thus, we analyzed each microbiome using pyrosequencing of the colon of normal mice and DSS-induced colitis mice, and found that the relative abundance of Bacteroides vulgatus(B. vulgatus) was increased in the colon of DSS-induced colitis mice. Next, we confirmed that B. vulgatusregulates CD82 expression and promotes activation of NLRP3 inflammasome. CD82 binds to NLRP3 and BRCC3, with a higher affinity for BRCC3. This binding mediated degradation of NLRP3 by inhibition BRCC3-dependent K63-specific deubiquitination. Therefore, we verified the difference between DSS-induced colitis in CD82 KO mice and normal mice, and the effect of B. vulgatus on DSS-induced colitis in CD82 KO mice and normal mice. Deficiency of CD82 decreased the severity of colitis in mice with enhancing the level of IL-1β and IL-18. Also, administration of B. vulgatus increased the survival through mediating CD82 expression and activating BRCC-dependent deubiquitination of NLRP3 in mice. Taken together, suppression of CD82 reduced the pathogenesis of colitis with elevating the activation of NLRP3 inflammasome by BRCC-dependent K63 deubiquitination. Additionally, B. vulgatusmay be a novel therapeutic candidate for colitis. This work was supported by the NRF grant funded by the Korea government (MSIP) (2019R1I1A2A01064237).

Inhibition of CD82 improves colitis by increasing NLRP3 deubiquitination by BRCC3

CD82 is a transmembrane protein that is involved in cancer suppression and activates immune cells; however, information on the NLRP3 inflammasome is limited. Herein, we show that although CD82 suppressed the activation of the NLRP3 inflammasome in vivo and in vitro, CD82 deficiency decreased the severity of colitis in mice. Furthermore, two binding partners of CD82, NLRP3 and BRCC3, were identified. CD82 binding to these partners increased the degradation of NLRP3 by blocking BRCC3-dependent K63-specific deubiquitination. Previous studies have shown that CD82-specific bacteria in the colon microbiota called Bacteroides vulgatus (B. vulgatus) regulated the expression of CD82 and promoted the activation of the NLRP3 inflammasome. Accordingly, we observed that B. vulgatus administration increased mouse survival by mediating CD82 expression and activating NLRP3 in mice with colitis. Overall, this study showed that CD82 suppression reduced the pathogenesis of colitis by elevating the activation of the NLRP3 inflammasome through BRCC3-dependent K63 deubiquitination. Based on our findings, we propose that B. vulgatus is a novel therapeutic candidate for colitis.

Histone deacetylase 1 and 3 inhibitors alleviate colon inflammation by inhibiting Th17 cell differentiation.

BackgroundThe etiology of inflammatory bowel disease (IBD), including ulcerative colitis (UC) and Crohn's disease (CD), is not completely clear, but its pathogenesis is closely related to T helper 17 (Th17) cells. Several histone deacetylase (HDAC) inhibitors have been shown to exert potent anti‐inflammatory effects and modulate Th17 cell polarization. Owing to the large variety and broad expression of HDACs, finding specific therapeutic targets for IBD is of clinical importance.MethodsThe proportions of Th17 cells and interleukin (IL)‐17A produced between patients with UC and healthy volunteers were compared. The differentiation of human peripheral blood mononuclear cells (PBMCs) into Th17 cells was induced in vitro. Differentiated Th17 cells were treated with RGFP109 (RG), a selective inhibitor of HDAC1 and 3, to observe its effects on these cells. Subsequently, colitis was induced in mice and treated with RG. The proportion of Th17 cells, the severity of colitis in mice, and colon histopathology and immunohistochemistry were evaluated respectively.ResultsThe proportion of Th17 cells and IL‐17A production was significantly increased in patients with UC than in healthy individuals. RG inhibited the differentiation of human PBMCs into Th17 cells and reduced IL‐17A secretion in vitro. RG‐treated colitis mice had a lower Th17 ratio, mild colon inflammation, and decreased expression of HDAC1 and 3 in the colon.ConclusionsHDAC1 and 3 inhibitors can modulate the differentiation of inflammatory Th17 cells, downregulate IL‐17A levels, and exert anti‐inflammatory effects in experimental colitis mice, indicating that HDAC1 and 3 may be potential therapeutic targets for patients with IBD.

The dephosphorylation of FADD at S191 induces an excessive expansion of TCRαβ+ IELs in the intestinal mucosa.

Intestinal intraepithelial lymphocytes (IELs) play a crucial role in host defence against pathogens in the intestinal mucosa. The development of intestinal IELs is distinct from peripheral T lymphocytes and remains elusive. Fas-associated protein with death domain (FADD) is important for T cell development in the thymus. Here we describe a novel function of FADD in the IEL development. FADD (S191A), a mouse FADD mutant at Ser191 to Ala mimicking constitutively unphosphorylated FADD, promoted a rapid expansion of TCRαβ+ IELs, not TCRγδ+ IELs. Mechanism investigation indicated that the dephosphorylation of FADD was required for cell activation mainly in TCRαβ+ CD8+ T cells. Consistently, FADD (S191A) as dephosphorylated FADD led to a high NF-κB activation in the TCR-dependent cell expansion. In addition, The FADD (S191A)-induced abnormal IEL populations resulted in the increased incidence and severity of colitis in mice. In summary, FADD signalling is involved in the intestinal IEL development and might be a regulator for intestinal mucosal homeostasis.

An Apple a Day Keeps the Doctor Away: The Effect of a Low-Fat, High-Fiber Diet on Quality of Life, Inflammation, and Dysbiosis in Patients With Ulcerative Colitis

An Apple a Day Keeps the Doctor Away: The Effect of a Low-Fat, High-Fiber Diet on Quality of Life, Inflammation, and Dysbiosis in Patients With Ulcerative Colitis

The novel piperazino-enaminone JOAB-40 reduced colitis severity in mice via inhibition tumor necrosis factor-α and interleukin-1β

Brief introductionThe synthetic compound enaminone E121 has an established role as a potent anti-tussive, bronchodilator and anti-inflammatory agent in asthma, cough, and colitis induced animal models. The addition of an N-alkylated piperazine motif to the terminal end of E121 lead to the generation of various analogues such as JOAB-40. JOAB-40 was shown to be more potent than the lead compound E121 in inhibiting the expression of the chemokine receptor CCR2, ERK1/2 phosphorylation, and the release of pro-inflammatory cytokines in vitro. Main objective of the studyWe hypothesize that JOAB-40 is more potent than the lead compound E121 in reducing colitis severity in mice in part through inhibiting the release of TNFα and IL-1β. MethodsColitis was induced by dextran sulfate sodium (DSS) administration using prophylactic and treatment approaches. The severity of the inflammation was determined by the gross (macroscopic) and histological (microscopic) assessments. The levels of TNFα, IL-1β, and IL-10 release in response to lipopolysaccharide (LPS) stimulation from the adherent murine macrophage cell line J774.2 in vitro, and the circulating levels of TNFα in vivo was measured by ELISA-based technique. Significant findings from the studyE121 administration (1–60 mg/kg) in mice with established colitis (treatment approach) did not reduce colitis severity. On the other hand, JOAB-40 administration significantly reduced colitis severity in mice when administered using two approaches; a) prophylactic (given along colitis induction), and b) treatment (given after colitis was established) with doses as low as 10 mg/kg. The degree of inhibition of TNFα and IL-1β (but not IL-10) release from J774.2 cell line in response to LPS stimulation was more potent with JOAB-40 than E121. This was also observed in vivo in regards to the circulating levels of TNFα. Relevant contribution to knowledgeOur results indicate that JOAB-40 is more potent than E121 in reducing colitis severity in mice and may be a promising future therapeutic target for the management of inflammatory bowel disease (IBD).

Macrophages Compensate for Loss of Protein Tyrosine Phosphatase N2 in Dendritic Cells to Protect from Elevated Colitis.

Protein tyrosine phosphatase nonreceptor type 2 (PTPN2) plays a critical role in the pathogenesis of inflammatory bowel diseases (IBD). Mice lacking PTPN2 in dendritic cells (DCs) develop skin and liver inflammation by the age of 22 weeks due to a generalized loss of tolerance leading to uncontrolled immune responses. The effect of DC-specific PTPN2 loss on intestinal health, however, is unknown. The aim of this study was to investigate the DC-specific role of PTPN2 in the intestine during colitis development. PTPN2fl/flxCD11cCre mice were subjected to acute and chronic DSS colitis as well as T cell transfer colitis. Lamina propria immune cell populations were analyzed using flow cytometry. DC-specific PTPN2 deletion promoted infiltration of B and T lymphocytes, macrophages, and DCs into the lamina propria of unchallenged mice and elevated Th1 abundance during acute DSS colitis, suggesting an important role for PTPN2 in DCs in maintaining intestinal immune cell homeostasis. Surprisingly, those immune cell alterations did not translate into increased colitis susceptibility in acute and chronic DSS-induced colitis or T cell transfer colitis models. However, macrophage depletion by clodronate caused enhanced colitis severity in mice with a DC-specific loss of PTPN2. Loss of PTPN2 in DCs affects the composition of lamina propria lymphocytes, resulting in increased infiltration of innate and adaptive immune cells. However, this did not result in an elevated colitis phenotype, likely because increased infiltration of macrophages in the intestine upon loss of PTPN2 loss in DCs can compensate for the inflammatory effect of PTPN2-deficient DCs.

Onion bulb extract can both reverse and prevent colitis in mice via inhibition of pro-inflammatory signaling molecules and neutrophil activity.

Onion is one of the most commonly used plants in the traditional medicine for the treatment of various diseases. We recently demonstrated the anti-inflammatory properties of onion bulb extract (OBE) in reducing colitis severity in mice when administered at the same time of colitis induction. However, whether onion can reverse established colitis or even prevent its development has not been investigated. To test 1. whether OBE can reduce colitis severity when given either before (preventative approach) or after (treatment approach) colitis induction and if so, 2. what are the mechanisms by which onion can achieve these effects. Colitis was induced by dextran sulfate sodium (DSS) administration using treatment and preventative approaches. The severity of the inflammation was determined by the gross and histological assessments. The colonic level/activity of pro-inflammatory molecules and immune cell markers was assessed by immunofluorescence and western blotting analysis. In vitro neutrophil superoxide release and survival was assessed by chemilumenecense and Annexin-V/7AAD assays respectively. OBE treatment significantly reduced colitis severity in both approaches, the colonic expression/activity profile of pro-inflammatory molecules, inhibited WKYMVm-induced superoxide release, and increased spontaneous apoptosis of neutrophils in vitro. OBE can be used as an effective option in the prevention and/or the treatment of established colitis.

Creatine Transporter, Reduced in Colon Tissues From Patients With Inflammatory Bowel Diseases, Regulates Energy Balance in Intestinal Epithelial Cells, Epithelial Integrity, and Barrier Function

Patients with inflammatory bowel diseases (IBDs) have intestinal barrier dysfunction. Creatine regulates energy distribution within cells and reduces the severity of colitis in mice. We studied the functions of the creatine transporter solute carrier family 6 member 8 (SLC6A8, also called CRT) in intestinal epithelial cells (IECs) and mice, and we measured levels in mucosal biopsies from patients with IBD. Colon biopsy specimens from patients with IBD (30 with Crohn's disease and 27 with ulcerative colitis) and 30 patients without IBD (control individuals) and colon tissues from mice (with and without disruption of Crt) were analyzed by immunofluorescence, immunoblots, and/or quantitative reverse-transcription polymerase chain reaction (qRT-PCR). CRT was knocked down or overexpressed in T84 cells, which were analyzed by immunofluorescence, immunoblots, high-performance liquid chromatography (to measure creatine levels), qRT-PCR, transepithelial electrical resistance, barrier function, actin localization, wound healing, mitochondrial oxygen consumption, and glycolysis extracellular acidification rate assays. Organoids from colon cells of CRT-knockout mice and control mice were analyzed by qRT-PCR, immunoblot, and transepithelial electrical resistance. CRT localized around tight junctions (TJs) of T84 IECs. In analyses of IECs with CRT knockdown or overexpression, we found that CRT regulates intracellular creatine, barrier formation, and wound healing. CRT-knockout organoids also had diminished barrier formation. In the absence of adequate creatine, IECs transition toward a stressed, glycolysis-predominant form of metabolism; this resulted in leaky TJs and mislocalization of actin and TJ proteins. Colon tissues from patients with IBD had reduced levels of CRT messenger RNA compared with those from control individuals. In an analysis of IEC cell lines and colonoids derived from CRT-knockout mice, we found that CRT regulates energy balance in IECs and thereby epithelial integrity and barrier function. Mucosal biopsy specimens from patients with ulcerative colitis and inactive Crohn's disease have lower levels of CRT, which might contribute to the reduced barrier function observed in patients with IBD.