Gene–gene and gene–environment interactions in ulcerative colitis

Genome-wide association studies (GWAS) have identified at least 133 ulcerative colitis (UC) associated loci. The role of genetic factors in clinical practice is not clearly defined. The relevance of genetic variants to disease pathogenesis is still uncertain because of not characterized gene–gene and gene–environment interactions. We examined the predictive value of combining the 133 UC risk loci with genetic interactions in an ongoing inflammatory bowel disease (IBD) GWAS. The Wellcome Trust Case–Control Consortium (WTCCC) IBD GWAS was used as a replication cohort. We applied logic regression (LR), a novel adaptive regression methodology, to search for high-order interactions. Exploratory genotype correlations with UC sub-phenotypes [extent of disease, need of surgery, age of onset, extra-intestinal manifestations and primary sclerosing cholangitis (PSC)] were conducted. The combination of 133 UC loci yielded good UC risk predictability [area under the curve (AUC) of 0.86]. A higher cumulative allele score predicted higher UC risk. Through LR, several lines of evidence for genetic interactions were identified and successfully replicated in the WTCCC cohort. The genetic interactions combined with the gene-smoking interaction significantly improved predictability in the model (AUC, from 0.86 to 0.89, P = 3.26E?05). Explained UC variance increased from 37 to 42 % after adding the interaction terms. A within case analysis found suggested genetic association with PSC. Our study demonstrates that the LR methodology allows the identification and replication of high-order genetic interactions in UC GWAS datasets. UC risk can be predicted by a 133 loci and improved by adding gene–gene and gene–environment interactions.     

Enalapril inhibits nuclear factor-κB signaling in intestinal epithelial cells and peritoneal macrophages and attenuates experimental colitis in mice

Aims

Enalapril, an angiotensin-converting enzyme (ACE) inhibitor, has pleiotropic effects such as anti-inflammatory effects. This study investigated the effect of enalapril on the nuclear factor-kappa B (NF-κB) pathway and on experimental colitis.

Main methods

The human intestinal epithelial cell (IEC) line COLO 205 and peritoneal macrophages from C57BL/6 wild-type mice and IL-10-deficient (IL-10^−/−) mice were prepared and subsequently stimulated with lipopolysaccharide (LPS) alone or LPS plus enalapril. The effect of enalapril on NF-κB signaling was examined by western blotting to detect IκBα phosphorylation/degradation; an electrophoretic mobility shift assay (EMSA) to assess the DNA binding activity of NF-κB; and ELISAs to qualify IL-8, TNF-α, IL-6, and IL-12 production. In in vivo studies, dextran sulfate sodium (DSS)-induced acute colitis in wild-type mice and chronic colitis in IL-10^−/− mice were treated with or without enalapril. Colitis was quantified by histologic scoring, and the phosphorylation of IκBα in the colonic mucosa was assessed using immunohistochemistry.

Key findings

Enalapril significantly inhibited LPS-induced IκBα phosphorylation/degradation, NF-κB binding activity, and pro-inflammatory cytokine production in both IEC and peritoneal macrophages. The administration of enalapril significantly reduced the severity of colitis, as assessed based on histology in both murine colitis models. Furthermore, in colon tissue, the up-regulation of IκBα phosphorylation with colitis induction was attenuated in enalapril-treated mice.

Significance

Enalapril may block the NF-κB signaling pathway, inhibit the activation of IECs and macrophages, and attenuate experimental murine colitis by down-regulating IκBα phosphorylation. These findings suggest that enalapril is a potential therapeutic agent for inflammatory bowel disease.     

Fluoxetine inhibits NF-κB signaling in intestinal epithelial cells and ameliorates experimental colitis and colitis-associated colon cancer in mice

Although fluoxetine, a selective serotonin reuptake inhibitor, is known to demonstrate anti-inflammatory activity, little information is available on the effect of fluoxetine regarding intestinal inflammation. This study investigates the role of fluoxetine in the attenuation of acute murine colitis by suppression of the NF-κB pathway in intestinal epithelial cells (IEC). Fluoxetine significantly inhibited activated NF-κB signals and the upregulated expression of interleukin-8 (IL-8) in COLO 205 colon epithelial cells stimulated with tumor necrosis factor-α (TNF-α). Pretreatment with fluoxetine attenuated the increased IκB kinase (IKK) and IκBα phosphorylation induced by TNF-α. In a murine model, administration of fluoxetine significantly reduced the severity of dextran sulfate sodium (DSS)-induced colitis, as assessed by the disease activity index, colon length, and histology. In addition, the DSS-induced phospho-IKK activation, myeloperoxidase activity, a parameter of neutrophil accumulation, and the secretion of macrophage-inflammatory protein-2, a mouse homolog of IL-8, were significantly decreased in fluoxetine-pretreated mice. Moreover, fluoxetine significantly attenuated the development of colon cancer in mice inoculated with azoxymethane and DSS. These results indicate that fluoxetine inhibits NF-κB activation in IEC and that it ameliorates DSS-induced acute murine colitis and colitis-associated tumorigenesis, suggesting that fluoxetine is a potential therapeutic agent for the treatment of inflammatory bowel disease.     

Tumor necrosis factor-α and Muc2 mucin play major roles in disease onset and progression in dextran sodium sulphate-induced colitis

The sequential events and the inflammatory mediators that characterize disease onset and progression of ulcerative colitis (UC) are not well known. In this study, we evaluated the early pathologic events in the pathogenesis of colonic ulcers in rats treated with dextran sodium sulfate (DSS). Following a lag phase, day 5 of DSS treatment was found clinically most critical as disease activity index (DAI) exhibited an exponential rise with severe weight loss and rectal bleeding. Surprisingly, on days 1-2, colonic TNF-α expression (70-80-fold) and tissue protein (50-fold) were increased, whereas IL-1β only increased on days 7-9 (60-90-fold). Days 3-6 of DSS treatment were characterized by a prominent down regulation in the expression of regulatory cytokines (40-fold for IL-10 and TGFβ) and mucin genes (15-18 fold for Muc2 and Muc3) concomitant with depletion of goblet cell and adherent mucin. Remarkably, treatment with TNF-α neutralizing antibody markedly altered DSS injury with reduced DAI, restoration of the adherent and goblet cell mucin and IL-1β and mucin gene expression. We conclude that early onset colitis is dependent on TNF-α that preceded depletion of adherent and goblet cell mucin prior to epithelial cell damage and these biomarkers can be used as therapeutic targets for UC.     

Hsp60 and Hsp10 increase in colon mucosa of Crohn’s disease and ulcerative colitis

The purpose of this work was to determine in colon mucosa of Crohn’s disease (CD) and ulcerative colitis (UC) in relapse: a) the levels of the chaperonins Hsp60 and Hsp10; b) the quantity of inflammatory cells; and c) if the levels of chaperonins parallel those of inflammation cells. Twenty cases of CD and UC and twenty normal controls (NC) were studied using immunohistochemistry, Western blotting and immunofluorescence. Immunohistochemically, Hsp60 and Hsp10 were increased in both inflammatory bowel diseases (IBD) compared to NC. These results were confirmed by Western blotting. Hsp60 and Hsp10 occurred in the cytoplasm of epithelial cells in CD and UC but not in NC. Hsp60 and Hsp10 co-localised to epithelial cells of mucosal glands but not always in connective tissue cells of lamina propria, where only Hsp60 or, less often, Hsp10 was found. Cells typical of inflammation were significantly more abundant in CD and UC than in NC. Since chaperonins are key factors in the activation of the immune system leading to inflammation, we propose that they play a central role in the pathogenesis of the two diseases, which, consequently, ought to be studied as chaperonopathies.     

Ursolic acid inhibits nuclear factor-κB signaling in intestinal epithelial cells and macrophages,and attenuates experimental colitis in mice

Aims

Ursolic acid (UA), a natural pentacyclic triterpenoid acid, has been reported to show immunomodulatory activity. This study investigated the effects of UA on nuclear factor-kappa B (NF-κB) signaling in cells and experimental murine colitis.

Main methods

Human intestinal epithelial cells (IECs) COLO 205 and peritoneal macrophages from IL-10-deficient (IL-10^−/−) mice were pretreated with UA and then stimulated with tumor necrosis factor-α (TNF-α) and lipopolysaccharide (LPS), respectively. The expression of pro-inflammatory cytokines was determined by real-time RT-PCR and ELISA. The effect of UA on NF-κB signaling was examined by immunoblot analysis to detect IκBα phosphorylation/degradation and electrophoretic mobility shift assay to assess the DNA binding activity of NF-κB. For in vivo studies, dextran sulfate sodium (DSS)-induced acute colitis in C57BL/6 wild-type mice and chronic colitis in IL-10^−/− mice were treated with or without UA. Colitis was quantified by histopathologic evaluation. Immunohistochemical staining for phosphorylated IκBα was performed in the colonic tissue.

Key findings

UA significantly inhibited the production of pro-inflammatory cytokines, IκBα phosphorylation/degradation and NF-κB DNA binding activity in both IEC and IL-10^−/− peritoneal macrophages stimulated with TNF-α and LPS, respectively. UA significantly reduced the severity of DSS-induced murine colitis, as assessed by the disease activity index, colon length, and histopathology. UA also significantly ameliorated the severity of colitis in IL-10^−/− mice. Furthermore, UA suppressed IκBα phosphorylation in the colonic tissue.

Significance

UA inhibits NF-κB activation in both IECs and macrophages, and attenuates experimental murine colitis. These results suggest that UA is a potential therapeutic agent for inflammatory bowel disease.     

Krüppel-like factor 5 protects against murine colitis and activates JAK-STAT signaling in vivo

Inflammatory bowel disease (IBD), which is characterized by chronic or recurring inflammation of the gastrointestinal tract, affects 1.4 million persons in the United States alone. KLF5, a Krüppel-like factor (KLF) family member, is expressed within the epithelia of the gastrointestinal tract and has been implicated in rapid cell proliferation, migration, and remodeling in a number of tissues. Given these functions, we hypothesized that constitutive Klf5 expression would protect against the development of colitis in vivo. To examine the role of KLF5 in vivo, we used the Villin promoter to target Klf5 to the entire horizontal axis of the small intestine and colon. Villin-Klf5 transgenic mice were born at normal Mendelian ratios and appeared grossly normal to at least 1 year of age. Surprisingly, there were no significant changes in cell proliferation or in the differentiation of any of the intestinal lineages within the duodenum, jejunum, ileum, and colon of Villin-Klf5 mice, compared to littermate controls. However, when Villin-Klf5 mice were treated with dextran sodium sulfate (DSS) to induce colitis, they developed less colonic injury and significantly reduced disease activity scores than littermate controls. The mechanism for this decreased injury may come via JAK-STAT signaling, the activation of which was increased in colonic mucosa of DSS treated Villin-Klf5 mice compared to controls. Thus, KLF5 and its downstream mediators may provide therapeutic targets and disease markers for IBD or other diseases characterized by injury and disruption of intestinal epithelia.     

DNA methylation-associated colonic mucosal immune and defense responses in treatment-na?ve pediatric ulcerative colitis

Inflammatory bowel diseases (IBD) are emerging globally, indicating that environmental factors may be important in their pathogenesis. Colonic mucosal epigenetic changes, such as DNA methylation, can occur in response to the environment and have been implicated in IBD pathology. However, mucosal DNA methylation has not been examined in treatment-naïve patients. We studied DNA methylation in untreated, left sided colonic biopsy specimens using the Infinium HumanMethylation450 BeadChip array. We analyzed 22 control (C) patients, 15 untreated Crohn’s disease (CD) patients, and 9 untreated ulcerative colitis (UC) patients from two cohorts. Samples obtained at the time of clinical remission from two of the treatment-naïve UC patients were also included into the analysis. UC-specific gene expression was interrogated in a subset of adjacent samples (5 C and 5 UC) using the Affymetrix GeneChip PrimeView Human Gene Expression Arrays. Only treatment-naïve UC separated from control. One-hundred-and-twenty genes with significant expression change in UC (> 2-fold, P < 0.05) were associated with differentially methylated regions (DMRs). Epigenetically associated gene expression changes (including gene expression changes in the IFITM1, ITGB2, S100A9, SLPI, SAA1, and STAT3 genes) were linked to colonic mucosal immune and defense responses. These findings underscore the relationship between epigenetic changes and inflammation in pediatric treatment-naïve UC and may have potential etiologic, diagnostic, and therapeutic relevance for IBD.     

Natural flavone tricin exerted anti-inflammatory activity in macrophage via NF-κB pathway and ameliorated acute colitis in mice

BackgroundUlcerative colitis is a subtype of inflammatory bowel disease, characterized by relapsing inflammation in the gastrointestinal tract with limited treatment options. Previous studies suggested that the natural compound tricin, a flavone isolated from rice bran, could suppress chemically-induced colitis in mice, while our recent study also demonstrated the anti-metastatic effect of tricin in colon tumor-bearing mice.Hypothesis/PurposeHere we further investigated the underlying mechanism of the inhibitory effects of tricin on lipopolysaccharides-activated macrophage RAW264.7 cells and explored the efficacy of tricin in acute colitis mouse model induced by 4.5% dextran sulfate sodium (DSS) for 7 days.MethodsTricin (75, 100, and 150 mg/kg) or the positive control drug sulfasalazine (200 mg/kg) were orally administered to mice for 7 days. Stool consistency scores, stool blood scores, and body weight were recorded daily. Disease activity index (DAI) was examined on day 7, and colon tissues were collected for biochemical analyses. The fecal microbiome of colitis mice after tricin treatment was characterized for the first time in this study using 16S rDNA amplicon sequencing.ResultsResults showed that tricin (50 µM) remarkably reduced nitric oxide production in lipopolysaccharides-activated RAW264.7 cells and the anti-inflammatory activity of tricin was shown to act through the NF-κB pathway. Besides, tricin treatment at 150 mg/kg significantly reversed colon length reduction, reduced myeloperoxidase activities and DAI scores, as well as restored the elevated myeloid-derived suppressive cells population in acute colitis mice. The influence from DSS on gut microbiota, such as the increased population of Proteobacteria phylum and Ruminococcaceae family, was shown to be relieved after tricin treatment.ConclusionOur present study firstly demonstrated that tricin ameliorated acute colitis by improving colonic inflammation and modulating gut microbiota profile, which supports the potential therapeutic use of tricin for colitis treatment.     

Effect of COX-2 inhibitor lumiracoxib and the TNF-α antagonist etanercept on TNBS-induced colitis in Wistar rats

Crohn's disease (CD) is associated with gut barrier dysfunction. Besides the baseline barrier defect, a subgroup of patients also expresses an intestinal barrier hyperresponsiveness to nonsteroidal anti-inflammatory drugs. On the other hand, the anti-tumour necrosis factor alpha (TNF-α) treatment has brought benefits to these patients. Thus, this study aimed to evaluate the effect of lumiracoxib, a selective-cyclooxygenase-2 (COX-2) inhibitor, and Etanercept (ETC), a TNF-α antagonist on the 2,4,6-trinitrobenzene sulfonic acid (TNBS)-induced experimental colitis. A total of 47 Wistar rats were randomized into seven groups, as follows: (1) Sham: sham induced-colitis; (2) TNBS: nontreated induced-colitis; (3) Lumiracoxib control; (4) Lumiracoxib-treated induced-colitis; (5) ETC control; (6) ETC-treated induced-colitis; (7) Lumiracoxib-ETC-treated induced-colitis. Rats from groups 6 and 7 presented significant improvement of macroscopic and histopathological damages in the distal colon. The gene expression of COX-2 mRNA, as well of TNF-α mRNA, decreased significantly in groups 6 and 7 compared to the TNBS nontreated and lumiracoxib-treated groups. The treatment only with lumiracoxib did not reduce the inflammation on TNBS-induced experimental colitis. ETC attenuated the damage seen in the colon and reduced the inflammation caused by TNBS. Our results suggest that down-regulation of TNF-α and COX-2 resulted in a decrease in inflammation caused by TNBS and thus provided some protection from the colonic damage caused by TNBS.     

No association between the SOCS-1 −1478CA/del polymorphism and ulcerative colitis in Turkish subjects

Suppressor of cytokine signaling (SOCS)-1 is an essential regulator of many cytokine signaling pathways, including those upregulated in the inflamed colonic mucosa of patients with ulcerative colitis. We sought to investigate whether the functional SOCS-1 ?1478CA>del polymorphism is associated with UC susceptibility and its disease phenotype in a Turkish clinical sample. A total of 104 subjects were enrolled in a case–control study (52 UC cases and 52 controls). The SOCS-1 ?1478CA>del polymorphism was genotyped using a polymerase chain reaction-restriction fragment length polymorphism (PCR–RFLP) method. The odds ratio of the del allele for UC relative to the CA allele was not significant (OR = 1.04, 95 % CI 0.59–1.82, P = 0.88). These results did not change after adjustment for age and sex in multivariable regression analysis (OR = 1.07, 95 % CI 0.42–1.69, P = 0.73). When the SOCS-1 ?1478CA>del polymorphism was analyzed among UC patients according to continuous disease and non-continuous disease, the del allele was not associated with disease recurrence (OR = 1.56, 95 % CI 0.78–4.56, P = 0.83). Furthermore, when we divided UC patients into two groups according to a previous history of colectomy, we found no significant effect of the del allele (OR = 1.94, 95 % CI 0.55–5.61, P = 0.91). Taken together, these findings suggest that SOCS-1 ?1478CA>del polymorphism does not contribute to UC susceptibility and its disease phenotype in Turkish subjects.     

Induction of TGF-β and IL-10 production in dendritic cells using astilbin to inhibit dextran sulfate sodium-induced colitis

Astilbin, a major bioactive compound from Rhizoma smilacis glabrae, has been reported to possess anti-inflammatory properties. Our study first evaluated astilbin on dextran sulfate sodium (DSS)-induced acute colitis in mice. By intraperitoneal injection of astilbin, the severity of colitis was attenuated, and the serum levels of IL-10 and TGF-β were increased. Using flow cytometry, a higher number of IL-10⁺ dendritic cells (DCs) and TGF-β⁺ DCs and a lower number of CD86⁺ DCs, IL-12 p40⁺ DCs, and IL-1β⁺ DCs were detected in the spleen of mice with colitis after astilbin treatment. The administration of astilbin also resulted in the upregulation of CD103⁺ expression in colonic DCs. In a coculture system, murine bone marrow-derived DCs pretreated with astilbin resulted in an enhanced production of CD4⁺CD25⁺Foxp3⁺ T cells. The results of this study show that astilbin could be a candidate drug for inflammatory bowel disease by mediating the regulatory functions of DCs.     

Spatiotemporal regulation of galectin-1-induced T-cell death in lamina propria from Crohn’s disease and ulcerative colitis patients

Inflammatory bowel disease (IBD), including Crohn’s disease (CD) and ulcerative colitis (UC), is characterized by chronic, relapsing intestinal inflammation. Galectin-1 (Gal-1) is an endogenous lectin with key pro-resolving roles, including induction of T-cell apoptosis and secretion of immunosuppressive cytokines. Despite considerable progress, the relevance of Gal-1-induced T-cell death in inflamed tissue from human IBD patients has not been ascertained. Intestinal biopsies and surgical specimens from control patients (n?=?52) and patients with active or inactive IBD (n?=?97) were studied. Gal-1 expression was studied by RT-qPCR, immunoblotting, ELISA and immunohistochemistry. Gal-1-specific ligands and Gal-1-induced apoptosis of lamina propria (LP) T-cells were determined by TUNEL and flow cytometry. We found a transient expression of asialo core 1-O-glycans in LP T-cells from inflamed areas (p?<?0.05) as revealed by flow cytometry using peanut agglutinin (PNA) binding and assessing dysregulation of the core-2 β 1-6-N-acetylglucosaminyltransferase 1 (C2GNT1), an enzyme responsible for elongation of core 2 O-glycans. Consequently, Gal-1 binding was attenuated in CD3⁺CD4⁺ and CD3⁺CD8⁺ LP T-cells isolated from inflamed sites (p?<?0.05). Incubation with recombinant Gal-1 induced apoptosis of LP CD3⁺ T-cells isolated from control subjects and non-inflamed areas of IBD patients (p?<?0.05), but not from inflamed areas. In conclusion, our findings showed that transient regulation of the O-glycan profile during inflammation modulates Gal-1 binding and LP T-cell survival in IBD patients.

     

Alterations in lipid,amino acid,and energy metabolism distinguish Crohn’s disease from ulcerative colitis and control subjects by serum metabolomic profiling

Introduction

Biomarkers are needed in inflammatory bowel disease (IBD) to help define disease activity and identify underlying pathogenic mechanisms. We hypothesized that serum metabolomics, which produces unique metabolite profiles, can aid in this search.

Objectives

The aim of this study was to characterize serum metabolomic profiles in patients with IBD, and to assess for differences between patients with ulcerative colitis (UC), Crohn’s disease (CD), and non-IBD subjects.

Methods

Serum samples from 20 UC, 20 CD, and 20 non-IBD control subjects were obtained along with patient characteristics, including medication use and clinical disease activity. Non-targeted metabolomic profiling was performed using ultra-high performance liquid chromatography/mass spectrometry (UPLC-MS/MS) optimized for basic or acidic species and hydrophilic interaction liquid chromatography (HILIC/UPLC-MS/MS).

Results

In total, 671 metabolites were identified. Comparing IBD and control subjects revealed 173 significantly altered metabolites (27 increased and 146 decreased). The majority of the alterations occurred in lipid-, amino acid-, and energy-related metabolites. Comparing only CD and control subjects revealed 286 significantly altered metabolites (54 increased and 232 decreased), whereas comparing UC and control subjects revealed only five significantly altered metabolites (all decreased). Hierarchal clustering using significant metabolites separated CD from UC and control subjects.

Conclusions

We demonstrate that a number of lipid-, amino acid-, and tricarboxylic acid cycle-related metabolites were significantly altered in IBD patients, more specifically in CD. Therefore, alterations in lipid and amino acid metabolism and energy homeostasis may play a key role in the pathogenesis of CD.

     

Iridoid glycosides fraction of Folium syringae leaves modulates NF-κB signal pathway and intestinal epithelial cells apoptosis in experimental colitis

Background and Aims

Iridoid glycosides (IG), the major active fraction of F. syringae leaves has been demonstrated to have strong anti-inflammatory properties to ulcerative colitis (UC) in our previous study. The aim of this study was to investigate whether IG modulates the inflammatory response in experimental colitis at the level of NF-κB signal pathway and epithelial cell apoptosis.

Methods

UC in rats was induced by administration with dextran sulfate sodium (DSS) in drinking water. The inflammatory damage was assessed by disease activity index (DAI), macroscopic findings, histology and myeloperoxidase (MPO) activity. The effect of IG on pro-inflammatory cytokines TNF-α, IL-8, COX-2 and regulatory peptide TGF-β1 was measured. Epithelial cell apoptosis and the protein and mRNA expressions of Fas/FasL, Bcl-2/Bax, caspase-3, NF-κB p65, IκBα, p-IκBα and IKKβ were detected by TUNEL method, immunohistochemistry, Western blotting and real-time quantitative PCR, respectively.

Results

IG significantly ameliorated macroscopic damage and histological changes, reduced the activity of MPO, and strongly inhibited epithelial cell apoptosis. Moreover, IG markedly depressed TNF-α, IL-8, COX-2 and TGF-β1 levels in the colon tissues in a dose-dependent manner. Furthermore, IG significantly blocked of NF-κB signaling by inhibiting IκBα phosphorylation/degradation and IKKβ activity, down-regulated the protein and mRNA expressions of Fas/FasL, Bax and caspase-3, and activated Bcl-2 in intestinal epithelial cells.

Conclusions

These results demonstrated for the first time that IG possessed marked protective effects on experimental colitis through inhibition of epithelial cell apoptosis and blockade of NF-κB signal pathway.     

Altered angiogenic balance in ulcerative colitis: a key to impaired healing?

Angiogenesis is an essential component of ulcer healing since it assures delivery of oxygen and nutrients to the healing site. Previous studies demonstrated increased serum and tissue levels of vascular endothelial growth factor (VEGF, the most potent angiogenic growth factor) in patients with active ulcerative colitis (UC) and animal models of UC. However, there is no explanation why the healing of UC-related mucosal injury is impaired despite increased expression of VEGF. Expression of angiogenesis inhibitors, angiostatin and/or endostatin, in UC has not been determined before. We examined expression of VEGF, angiostatin, and endostatin in two models of experimental UC. The results revealed that in addition to increased VEGF, both endostatin and angiostatin levels were markedly (2-3-folds) increased in colonic mucosa at early stage of experimental UC. This is the first demonstration that colitis triggers increase in angiostatin and endostatin levels. The results may explain why mucosal lesions heal slowly despite increased VEGF levels, and may provide a novel and mechanistic insight into UC.     

β-Sitosterol improves experimental colitis in mice with a target against pathogenic bacteria

In this article, we aim to examine the novel effects of β-sitosterol on murine experimental colitis. β-Sitosterol significantly reduces the weight loss, colon length, and alleviated microscopic appearances of colitis induced by dextran sulfate sodium. This compound also decreases the levels of TNF-α, IL-6, and IL-1β in intestinal tissue of mice with experimental colitis in a concentration-dependent manner. β-Sitosterol treatment to intestinal epithelial cells significantly increases expression of antimicrobial peptides and reduces survival of intracellular Salmonella typhimurium. These results showed the multiple effects of β-sitosterol against pathogenic bacteria for a novel approach to the treatment of colonic inflammation.     

Identifying candidate genes for discrimination of ulcerative colitis and Crohn’s disease

In this study we aimed to screen effective biomarkers for differential diagnosis of ulcerative colitis (UC) and Crohn’s disease (CD). By using the gene expression profile dataset GSE24287 including 47 ileal CD, 27 UC and 25 non-inflammatory bowel diseases control downloaded from Gene Expression Omnibus database, we identified the differentially expressed genes (DEGs) between UC patients and controls as well as between CD patients and controls (|log₂FC(fold change)| > 1 and p < 0.05). Then Gene Ontology (GO) functional enrichment analyses were performed for these DEGs in two groups, followed by the construction of weight PPI (protein–protein interaction) networks. Subnets enriched for the PPIs and differentially expressed genes were constructed based on the weight PPI networks. The overlapping genes between the genes in the top 10 subnets with smallest p value and the DEGs were selected as the candidate genes of disease. A total of 75 DEGs were identified in UC group and 87 ones in CD group. There were 69 and 57 specific DEGs in CD group and UC group, respectively. The DEGs in CD group were mainly enriched in “inflammatory response” and “defense response”, while the most significantly enriched GO terms in UC group were “anion transport” and “chemotaxis”. FOS and SOCS3 were identified as candidate genes for CD and other three genes HELB, ZBTB16 and FAM107A were candidate genes for UC. In conclusion, there were distinct genetic alterations between UC and CD. The candidate genes identified in current study may be used as biomarkers for differential diagnosis of CD and UC.