Therapeutic Target In Inflammatory Bowel Disease Research Articles

Serum fibroblast growth factor 19 level correlates inversely with clinical and endoscopic activity of inflammatory bowel disease.

Inflammatory bowel disease (IBD), including ulcerative colitis (UC) and Crohn's disease (CD), is a chronic condition with relapsing-remitting course. Diarrhea and abdominal pain are the most common IBD symptoms. Fibroblast growth factor 19 (FGF19) is an endocrine factor that inhibits hepatic bile acid production and may be used as a diagnostic marker for bile acid malabsorption. To assess serum FGF19 levels in active and inactive phases of IBD and find a potential correlation between FGF19 and disease activity. Fasting serum FGF19 levels were measured in 105 IBD patients (47 UC patients, 41 CD patients without previous ileocecal resection (NR-CD), 17 CD patients after ileocecal resection (IR-CD), and 17 control subjects). The disease activity was assessed using clinical, laboratory and endoscopic criteria. Inverse correlations were found between FGF19 level and intensity of diarrhea (in UC), abdominal pain intensity (in UC and IR-CD) and inflammatory markers (in UC and IR-CD). Moreover, FGF19 concentration was inversely correlated with clinical and endoscopic activity indices in UC and CD. Fluctuations in FGF19 level related to clinical and endoscopic activity of UC and CD revealed a clear pattern of higher values in remission than in active disease phases. Fibroblast growth factor 19 may serve as a potential diagnostic biomarker and constitute a new therapeutic target in IBD.

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

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

Endoplasmic reticulum stress is upregulated in inflammatory bowel disease and contributed TLR2 pathway-mediated inflammatory response

Objective Endoplasmic reticulum stress (ERS) and Toll-like receptor 2 (TLR2) signaling play an important role in inflammatory bowel disease (IBD); however, the link between TLR2 and ERS in IBD is unclear. This study investigated whether Thapsigargin (TG) -induced ER protein expression levels contributed to TLR2-mediated inflammatory response. Methods The THP-1 cells were treated with TLR2 agonist (Pam3CSK4), ERS inducer Thapsigargin (TG) or inhibitor (TUDCA). The mRNA expressions of TLR1-TLR10 were detected by qPCR. The production and secretion of inflammatory factors were detected by PCR and ELISA. Immunohistochemistry was used to detect the expressions of GRP78 and TLR2 in the intestinal mucosa of patients with Crohn’s disease (CD). The IBD mouse model was established by TNBS in the modeling group. ERS inhibitor (TUDCA) was used in the treatment group. Results The expression of TLRs was detected via polymerase chain reaction (PCR) in THP-1 cells treated by ERS agonist Thapsigargin (TG). According to the findings, TG could promote TLR2 and TLR5 expression. Subsequently, in TLR2 agonist Pam3CSK4 induced THP-1 cells, TG could lead to increased expression of the inflammatory factors such as TNF-α, IL-1β and IL-8, and ERS inhibitor (TUDCA) could block this effect. However, Pam3CSK4 did not significantly impact the GRP78 and CHOP expression. Based upon the immunohistochemical results, TLR2 and GRP78 expression were significantly increased in the intestinal mucosa of patients with Crohn’s disease (CD). For in vivo experiments, TUDCA displayed the ability to inhibit intestinal mucosal inflammation and reduce GRP78 and TLR2 proteins. Conclusions ERS and TLR2 is upregulated in inflammatory bowel disease, ERS may promote TLR2 pathway-mediated inflammatory response. Moreover, ERS and TLR2 signaling could be novel therapeutic targets for IBD.

Cytokine induced inflammatory bowel disease model using organ-on-a-chip technology

Over 2 million people in North America suffer from inflammatory bowel disease (IBD), a chronic and idiopathic inflammatory condition. While previous research has primarily focused on studying immune cells as a cause and therapeutic target for IBD, recent findings suggest that non-immune cells may also play a crucial role in mediating cytokine and chemokine signaling, and therefore IBD symptoms. In this study, we developed an organ-on-a-chip co-culture model of Caco2 epithelial and HUVEC endothelial cells and induced inflammation using pro-inflammatory cytokines TNF-α and IFN-γ. We tested different concentration ranges and delivery orientations (apical vs. basal) to develop a consistently inducible inflammatory response model. We then measured pro-inflammatory cytokines and chemokines IL-6, IL-8, and CXCL-10, as well as epithelial barrier integrity. Our results indicate that this model 1. induces IBD-like cytokine secretion in non-immune cells and 2. decreases barrier integrity, making it a feasible and reliable model to test the direct actions of potential anti-inflammatory therapeutics on epithelial and endothelial cells.

Antibody targeting TSLP suppresses DSS-induced colitis and activation of the JAK2/STAT5 pathway in mice.

There is currently no safe or effective treatment for inflammatory bowel disease (IBD), which is defined as recurrent and persistent intestinal inflammation. Thymic stromal lymphopoietin (TSLP) has been shown to be associated with the pathogenesis of IBD, and the JAK2/STAT5 signalling pathway has demonstrated much promise as a novel therapeutic target for IBD. In this study, we first evaluated levels of TSLP in dextran sodium sulphate (DSS)-induced IBD mice. Second, we applied tezepelumab, an anti-TSLP monoclonal antibody (20μg per mouse, intraperitoneally), to DSS-induced IBD mice and quantified the signs of histopathological change, intestinal inflammation, and integrity of the mucosal barrier. In addition, the effect of DSS and/or tezepelumab on the phosphorylation of the JAK/STAT pathway was investigated. TSLP expression levels were elevated in DSS-induced IBD mice, whereas TSLP antibody treatment suppressed the pathological features associated with IBD and alleviated intestinal inflammation and mucosal barrier disruption. Moreover, level of phosphorylated JAK2/STAT5 were increased in DSS-induced IBD mice, but were strongly decreased in the presence of tezepelumab. Our findings suggest that targeting TSLP via the JAK2/STAT5 signalling pathway may be an effective approach for the treatment of IBD.

Blocking the Apelin Receptor (APJ) Attenuates TNBS-Induced Colitis in Rats

Objective: The apelinergic system, consisting of apelin, ELABELA, and the apelin receptor (APJ), has a wide range of roles in physiological and pathophysiological processes in tissues. The effects of increased apelin and APJ as an indicator of damage in inflammatory conditions or as a compensatory mechanism are not fully clear in inflammatory bowel disease (IBD). This study was designed to assess the role of APJ in 2,4,6-trinitrobenzene sulfonic acid (TNBS)-induced colitis model. Methods: Colitis in adult male Wistar rats were induced by intrarectally administered TNBS (30 mg b.w. in 50% ethanol). While the control group was treated with only saline to the colon, the TNBS+F13A and F13A groups received the APJ antagonist F13A (30 µg/kg/day, i.v.) for 3 days, starting immediately after TNBS or saline administration, respectively. Results: A decrease in body weight and an increase in colon weight/length ratio and stool consistency score were observed in the TNBS group. TNBS caused an increase in the myeloperoxidase (MPO) activity and the number of proinflammatory cytokines (TNF-α, IL-1β, and IL-6), as well as apelin production, leading to mucosal ulceration, necrosis, and submucosal edema in the colon. While F13A administration to the control did not cause any change in the colon, F13A administration immediately after TNBS greatly reduced the effects of TNBS. Conclusion: APJ is involved in the development of damage in colitis induced by TNBS. F13A reduces the level of damage, inflammatory cell infiltration, and MPO enzyme activity. APJ may be a therapeutic target in IBD.

The NRF2/Keap1 pathway as a therapeutic target in inflammatory bowel disease.

Oxidative stress (OS) is an important pathophysiological mechanism in inflammatory bowel disease (IBD). However, clinical trials investigating compounds directly targeting OS in IBD yielded mixed results. The NRF2 (nuclear factor erythroid 2-related factor 2)/Keap1 (Kelch-like ECH-associated protein 1) pathway orchestrates cellular responses to OS, and dysregulation of this pathway has been implicated in IBD. Activation of the NRF2/Keap1 pathway may enhance antioxidant responses. Although this approach could help to attenuate OS and potentially improve clinical outcomes, an overview of human evidence for modulating the NRF2/Keap1 axis and more recent developments in IBD is lacking. This review explores the NRF2/Keap1 pathway as potential therapeutic target in IBD and presents compounds activating this pathway for future clinical applications.

Emerging roles of host and microbial bioactive lipids in inflammatory bowel diseases.

The intestinal tract harbors diverse microorganisms, host- and microbiota-derived metabolites, and potentially harmful dietary antigens. The epithelial barrier separates the mucosa, where diverse immune cells exist, from the lumen to avoid excessive immune reactions against microbes and dietary antigens. Inflammatory bowel disease (IBD), such as ulcerative colitis and Crohn's disease, is characterized by a chronic and relapsing disorder of the gastrointestinal tract. Although the precise etiology of IBD is still largely unknown, accumulating evidence suggests that IBD is multifactorial, involving host genetics and microbiota. Alterations in the metabolomic profiles and microbial community are features of IBD. Advances in mass-spectrometry-based lipidomic technologies enable identification of changes in the composition of intestinal lipid species in IBD. Because lipids have a wide range of functions, including signal transduction and cell membrane formation, dysregulation of lipid metabolism drastically affects the physiology of the host and microorganisms. Therefore, a better understanding of the intimate interactions of intestinal lipids with host cells that are implicated in the pathogenesis of intestinal inflammation might aid in the identification of novel biomarkers and therapeutic targets for IBD. This review summarizes the current knowledge on the mechanisms by which host and microbial lipids control and maintain intestinal health and diseases. This article is protected by copyright. All rights reserved.

Blockade of IL-18 signaling downregulates homing of effector CD4+ T cells to the gut mucosa and provides protection from experimental IBD

Abstract The immunological complexity of inflammatory bowel disease (IBD) results in persistent intestinal inflammation in millions of patients. As an epithelial cell-derived cytokine essential in the differentiation of CD4+ T helper cells, interleukin 18 (IL-18) is emerging as a therapeutic target for IBD. When naïve CD4+ T cells are stimulated with IL-18, the production of IFNγ and differentiation of Th1 cells increase. IL18R1−/− CD4+ T cells produce less IFNγ and inflammatory cytokines compared to WT. To examine the viability of targeting IL-18 in vivo, colitis was induced in WT, IL18−/−, and IL18R1−/− mice by DSS. In both knockouts, lower proportions of IFNγ- and IL17-producing CD4+ T cells were observed in the colon along with lesser overall severity relative to WT. To further investigate, we examined the interplay of antigen presenting cells and CD4+ T cells in vitro. IL18R1−/− Th1 cells had decreased α4β7 and GPR15 expression when co-cultured with WT BMDCs. Meanwhile, IL18R1−/− Tregs had decreased IFNγ and CCR9 expression when co-cultured with WT BMDCs that were stimulated with LPS and retinoic acid, suggesting that IL-18 may play a role in the differential gut homing of CD4+ T cell subsets. When CD4+ T cells are transferred to Rag2−/−, mice receiving IL18R1−/− T cells possess significantly lower proportions of α4β7+ Th1 cells while the proportion of Tregs in the colon are increased. Treatment of mice with DSS or Mdr1a−/− colitis with an oral IL-18 inhibitor (20 mg/kg) resulted in decreased Th1 cells and neutrophils, lower histological scores and improved disease severity. From converging data, we deduce that inhibition of IL-18 may alleviate exacerbated immune responses associated with IBD, yielding a favorable therapeutic.

The HIF-prolyl hydroxylases have distinct and non-redundant biological roles in the pathogenesis of colitis-associated cancer

Colitis-associated colorectal cancer (CAC) is a severe complication of inflammatory bowel disease (IBD). HIF-prolyl hydroxylases (PHD1, PHD2, and PHD3) control cellular adaption to hypoxia and are considered promising therapeutic targets in IBD. However, their relevance in the pathogenesis of CAC remains elusive. We induced CAC in Phd1-/-, Phd2+/-, Phd3-/-, and WT mice with azoxymethane (AOM) and dextran sodium sulfate (DSS). Phd1-/- mice were protected against chronic colitis and displayed diminished CAC growth compared to WT mice. In Phd3 -/- mice, colitis activity and CAC growth remained unaltered. In Phd2+/- mice, colitis activity was unaffected, but CAC growth was aggravated. Mechanistically, Phd2 deficiency (i) increased the number of tumor-associated macrophages (TAMs) in AOM/DSS-induced tumors, (ii) promoted the expression of EGFR ligand epiregulin ( Ereg) in macrophages, and (iii) augmented signal transducer and activator of transcription 3 (STAT3) and extracellular signal-regulated kinase 1/2 (ERK1/2) signaling which at least in part contributed to aggravated tumor cell proliferation in colitis-associated tumors. Consistently, Phd2 deficiency in hematopoietic ( Vav:Cre-Phd2f/f) but not in intestinal epithelial cells ( Villin:Cre-Phd2f/f) increased CAC growth. In conclusion, the three different PHD isoenzymes have distinct and non-redundant, either promoting (PHD1), diminishing (PHD2), or neutral effects (PHD3) on CAC growth. KBK received funding from the German Cancer Aid. MJS. received funding from the German Research Foundation (DFG; STR 1570/1-1) and the Braun Foundation (Braun®; BBST-D-18-00018). MSch received funding from the German Federal Ministry of Education and Research (BMBF; 031L0084). JMH received funding from the Heidelberg Stiftung Chirurgie. This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

P003 MicroRNAs as biomarkers in Inflammatory Bowel Disease unclassified (IBDU) patient samples may predict the development from IBDU to Crohn’s Disease or Ulcerative Colitis

Abstract Background Differential diagnosis in Inflammatory Bowel Disease (IBD) is challenging; typically, discriminating Crohn’s Disease (CD) from Ulcerative Colitis (UC) among IBD unclassified (IBDU) patients is a diagnostic encounter in cases where the inflammatory lesions are restricted to the colon. MicroRNAs are found to be involved in the pathogenesis and are also evaluated as diagnostic biomarkers and therapeutic targets in IBD. Methods We obtained formalin fixed paraffin embedded (FFPE) colonic mucosal biopsies of 35 IBDU patients (including adults and children), and 8 IBD (4 CD and 4 UC) patients who were classified into CD or UC collected from the diagnostic endoscopy. Based on the patient charts, The IBDU samples were reclassified into CDs or UC or remained as IBDU after minimum 3 years clinical follow up, ie. 12 IBDU patients were reclassified as CD (IBDU-CD) and 15 IBDU patients as UC (IBDU-UC). Eight IBDU patients remained as IBDU. MicroRNA profiling was performed on all samples using Affymatrix GeneChip miRNA Arrays. Arrays were processed using pd.mirna.4.0 and oligo packages in R and were analysed using LIMMA package. Results We found that miR-3176 and miR-182-5p were upregulated in IBDU-CD and miR-671-5p, miR-668-5p, miR-4793-3p, and mir-6776 were upregulated in IBDU-UC with p values of less than 0.05 and 1< log [fold change] <-1 for all 6 microRNAs. Higher mucosal expression levels of miR-3176 and miR-182-5p in IBDU-CD samples compared to IBDU-UC samples, resulted in an area under the curve (AUC) of 0.87 (95% confidence interval (CI), 0.71 – 1.00) and 0.81 (CI, 0.63 – 1.00), respectively, in discriminating IBDU-CD from IBDU-UC. On the other hand, miR-3176 and miR-182-5p had AUCs of 0.69 (CI, 0.25-1.00) and 0.69 (CI, 0.21-1.00), respectively, in discriminating CD and UC. MicroRNA miR-671-5p had a higher AUC of 0.81 (CI, 0.48 - 1.00) for discriminating CDs and UCs, whereas in discriminating IBDU-CD and IBDU-UC, the AUC was only 0.64 (CI, 0.42 – 0.87). Conclusion We conclude that differential microRNA expression among IBDU patients can predict the development of IBDU to CD and IBDU to UC, and that the microRNA expression profile of IBDU patients differ from patients classified as CD or UC at time of diagnosis. Our findings suggest that IBDUs may have different pathogenic mechanisms for IBDU-CDs and IBDU-UCs.

Apelin expression is downregulated in T cells in a murine model of chronic colitis

Apelin (APL), an endogenous ligand for APJ, has been reported to be upregulated in a murine model of acute colitis induced by sodium dextran sulfate, as well as inflammatory bowel diseases (IBD) in humans. However, the mechanisms and functions of APL/APJ axis in the pathogenesis of IBD are unclear. We herein analyzed CD4+ T cells to determine the functions of APL in a murine model of chronic colitis induced in Rag deficient mice (Rag−/−). In colonic tissues of wild-type mice (WT), we found that APL was expressed especially in the lamina propria lymphocytes, where CD4+ T cells are dominant, rather than the epithelial cells. Unexpectedly, the APL expression was rather downregulated in the colonic tissue of the chronic colitis group compared to the control groups (Rag−/− before colitis induction and WT). The APL expression was downregulated when naïve T cells were differentiated into effecter T cells. A lack of APL resulted in decreased naïve T cells and increased effecter T cells in secondary lymphoid organs. A synthetic APL peptide, [Pyr1]-APL-13, increased IL-10 and decreased IFN-γ productions by effecter T cells. Administration of [Pyr1]-APL-13 improved survival rate in association with lessened colitis severity and decreased pro-inflammatory cytokine production. This is the first report showing immunological function of APL specifically on T cells, and these results indicate that APL/APJ axis may be a novel therapeutic target for IBD.

Mitotic spindle positioning protein (MISP) deficiency exacerbates dextran sulfate sodium (DSS)-induced colitis in mice.

Inflammatory bowel disease (IBD) is classified into two types: Crohn's disease and ulcerative colitis. In IBD, the imbalance between the pro-inflammatory and anti-inflammatory cytokines prevents recovery from the inflammatory state, resulting in chronic inflammation in the colon. The mitotic spindle positioning protein (MISP) is localized to the apical membrane in the colon. In this study, we observed increased expression of MISP in the intestinal epithelial cells in dextran sulfate sodium (DSS)-induced colitis in mice. MISP-deficient mice receiving DSS showed significant exacerbation of colitis (e.g., weight loss, loss of the crypts). The intestinal epithelial cells of the MISP-deficient mice showed a trend towards decreased cell proliferation after DSS treatment. Reverse transcription followed by quantitative polymerase chain reaction revealed that the expression levels of Tgfb1, an anti-inflammatory cytokine, were significantly reduced in the colon of MISP-deficient mice compared with the wild-type mice regardless of DSS treatment. These findings indicate that MISP may play a role in the recovery of the colon after inflammation through its anti-inflammatory and proliferative activities, suggesting that MISP may be a new therapeutic target for IBD.

Insilco prediction of the role of the FriZZled5 gene in colorectal cancer

IntroductionIn this study, we aimed to elucidate the crosstalk between the Wnt/β-catenin signaling pathway and colorectal cancer (CRC) associated with inflammatory bowel disease (IBD) using a bioinformatics analysis of putative common biomarkers and a systems biology approach. Materials and methodsThe following criteria were used to search the GEO and ArrayExpress databases for terms related to CRC and IBD: 1. The dataset containing the transcriptomic data, and 2. Untreated samples by medications or drugs. A total of 42 datasets were selected for additional analysis. The GEO2R identified the differentially expressed genes. The genes involved in the Wnt signaling pathway were extracted from the KEGG database. Enrichment analysis and miRNA target prediction were conducted through the ToppGene online tool. ResultsIn CRC datasets, there were 1168 up- and 998 down-regulated probes, whereas, in IBD datasets, there were 256 up- and 200 down-regulated probes. There were 65 upregulated and 57 downregulated genes shared by CRC and IBD. According to KEGG, there were 166 genes in the Wnt pathway. FriZZled5 (FZD5) was a down-regulated gene in both CRC and IBD, as determined by the intersection of CRC- and IBD-related DEGs with the Wnt pathway. It was also demonstrated that miR-191, miR-885-5p, miR-378a-3p, and miR-396-3p affect the FriZZled5 gene expression. ConclusionIt is possible that increased expression of miR-191 and miR-885-5p, or decreased expression of miR-378a -3p and miR396-3, in IBD and CRC results in decreased expression of the FZD5 gene. Based on the function of this gene, FZD5 may be a potential therapeutic target in IBD that progresses to CRC.

Plasminogen Activator Inhibitor-1 Potentiates Neutrophil Infiltration and Tissue Injury in Colitis.

The mechanism underlying inflammatory bowel disease (IBD) remains unclear. We aimed to identify early diagnostic biomarkers and understand their roles in the pathogenesis of IBD. Methods: We identified plasminogen activator inhibitor-1 (PAI-1) as a potential key gene that is upregulated in IBD based on published transcriptomic datasets. To further determine the role of PAI-1 in disease pathogenesis, we induced colitis in wild-type (WT) and PAI-1 knockout (KO) mice by administering dextran sulfate sodium (DSS). We used an RNA array of genes and 16S rRNA sequencing of the microbiome to analyze PAI-1 function. The colon and serum PAI-1 levels in humans were further evaluated for their diagnostic value. Results: PAI-1 expression was significantly increased in patients and DSS-induced WT mice but reduced in PAI-1 KO mice. These changes were associated with significantly decreased neutrophil infiltration in colonic tissues. The RNA array revealed that the CXC chemokines CXCL1 and CXCL5 and their common receptor CXCR2 were among the most significantly different genes between the PAI-1 KO mice with DSS-induced colitis and the WT mice. Mechanistically, PAI-1 deficiency led to blunted activation of the NF-κB pathway in the colon epithelium. The gut microbiome was altered in the PAI-1 KO mice, which showed enriched abundances of short-chain fatty acid-producing genera and diminished abundances of pathogenic genera. Receiver operating characteristic (ROC) curve analysis revealed the diagnostic value of PAI-1. Conclusions: Our data suggest a previously unknown function of PAI-1 inducing neutrophil-mediated chemokine expression by activating the NF-κB pathway and affecting the function of the gut microbiome. PAI-1 could be a potential diagnostic biomarker and a therapeutic target in IBD.

The role of NOD2 in intestinal immune response and microbiota modulation: A therapeutic target in inflammatory bowel disease.

As an intracellular pattern recognition receptor (PPR), the nucleotide-binding oligomerization domain-containing protein 2 (NOD2) triggers a cascade of immune responses. Previous studies of NOD2 regarding inflammatory bowel disease (IBD) mainly focused on the relevance of NOD2 mutations and loss within the disease onset and progression. With increasing research, more studies are exploring other functional roles and clinical applications of NOD2. In this review, we discuss the role of NOD2 in intestinal immune response and microbiota modulation in IBD and explore its clinical potential as a therapeutic target for IBD.

The HIF-prolyl hydroxylases have distinct and nonredundant roles in colitis-associated cancer.

Colitis-associated colorectal cancer (CAC) is a severe complication of inflammatory bowel disease (IBD). HIF-prolyl hydroxylases (PHD1, PHD2, and PHD3) control cellular adaptation to hypoxia and are considered promising therapeutic targets in IBD. However, their relevance in the pathogenesis of CAC remains elusive. We induced CAC in Phd1-/-, Phd2+/-, Phd3-/-, and WT mice with azoxymethane (AOM) and dextran sodium sulfate (DSS). Phd1-/- mice were protected against chronic colitis and displayed diminished CAC growth compared with WT mice. In Phd3-/- mice, colitis activity and CAC growth remained unaltered. In Phd2+/- mice, colitis activity was unaffected, but CAC growth was aggravated. Mechanistically, Phd2 deficiency (i) increased the number of tumor-associated macrophages in AOM/DSS-induced tumors, (ii) promoted the expression of EGFR ligand epiregulin in macrophages, and (iii) augmented the signal transducer and activator of transcription 3 and extracellular signal-regulated kinase 1/2 signaling, which at least in part contributed to aggravated tumor cell proliferation in colitis-associated tumors. Consistently, Phd2 deficiency in hematopoietic (Vav:Cre-Phd2fl/fl) but not in intestinal epithelial cells (Villin:Cre-Phd2fl/fl) increased CAC growth. In conclusion, the 3 different PHD isoenzymes have distinct and nonredundant effects, promoting (PHD1), diminishing (PHD2), or neutral (PHD3), on CAC growth.

Pep27 Mutant Immunization Inhibits Caspase-14 Expression to Alleviate Inflammatory Bowel Disease via Treg Upregulation.

Inflammatory bowel disease (IBD) is a highly prevalent gut inflammatory disorder. Complicated clinical outcomes prolong the use of conventional therapy and often lead to compromised immunity followed by adverse events and high relapse rates. Thus, a profound medical intervention is required. Previously, intranasal immunization of pneumococcal pep27 mutant (Δpep27) exhibited long-lasting protection against immune-related disorders. System biology analysis has predicted an inverse correlation between Δpep27 immunization and gastroenteritis. Recently, we established that Δpep27-elicited Tregs repressed Wnt5a expression and enhanced barrier integrity, suggesting the restoration of immunological tolerance. Therefore, we evaluated whether Δpep27 can alleviate IBD. Δpep27 dose-dependent response was analyzed in dextran sulfate sodium-induced mice using transcriptome analysis. Pro- and anti-inflammatory signatures were cross-correlated by quantitative PCR and western blot analyses. To address the hierarchy regulating the activity of caspase-14, an undefined marker in IBD, and regulatory T cells (Tregs), antibody-based neutralization studies were conducted. Fecal microbiome profiles were analyzed by 16S rRNA pyrosequencing. Δpep27 significantly attenuated dextran sulfate sodium-induced oxidative stress parameters, proinflammatory cytokines, caspase-14 expression level, and upregulated tight junction, anti-inflammatory genes IL-10 and TGF-β1 via upregulation of Tregs to restore healthy gut microbiota. Neutralization studies unveiled that ∆pep27 had a remedial effect via Treg upregulation. Caspase-14, being an important mediator in the pathogenesis of IBD, can be an alternate therapeutic target in IBD. ∆pep27-increased Tregs repressed caspase-14 expression and reversed gut microbial dysbiosis, aiding to re-establish immunological tolerance.

Compositional changes in fecal microbiota associated with clinical phenotypes and prognosis in Korean patients with inflammatory bowel disease.

The fecal microbiota of Korean patients with inflammatory bowel disease (IBD) was investigated with respect to disease phenotypes and taxonomic biomarkers for diagnosis and prognosis of IBD. Fecal samples from 70 ulcerative colitis (UC) patients, 39 Crohn's disease (CD) patients, and 100 healthy control individuals (HC) were collected. The fecal samples were amplified via polymerase chain reaction and sequenced using Illumina MiSeq. The relationships between fecal bacteria and clinical phenotypes were analyzed using the EzBioCloud database and 16S microbiome pipeline. The alpha-diversity of fecal bacteria was significantly lower in UC and CD (P<0.05) compared to that in HC. Bacterial community compositions in UC and CD were significantly different from that of HC according to Bray-Curtis dissimilarities, and there was also a difference between community composition in UC and CD (P=0.01). In UC, alpha-diversity was further decreased when the disease was more severe and the extent of disease was greater, and community composition significantly differed depending on the extent of the disease. We identified 9 biomarkers of severity and 6 biomarkers of the extent of UC. We also identified 5 biomarkers of active disease and 3 biomarkers of ileocolonic involvement in CD. Lachnospiraceae and Ruminococcus gnavus were biomarkers for better prognosis in CD. The fecal microbiota profiles of IBD patients were different from those of HC, and several bacterial taxa may be used as biomarkers to determine disease phenotypes and prognosis. These data may also help discover new therapeutic targets for IBD.

Inverse-agonist (SMM-189) suppresses colitis by inducing endogenous cannabinoids and attenuating Th17, neutrophils, natural killer cells

Abstract The cause of inflammatory bowel disease (IBD), including Crohn’s disease (CD) and ulcerative colitis (UC), are multi-factorial and include activated immune cells, chronic inflammation, genetics, and environmental exposure. It is well known that endocannabinoids mediate protection against intestinal inflammation and other autoimmune diseases. However, the effect of cannabinoid receptors induction by inverse-agonist during experimental colitis has not been investigated. Here, we investigate the activation of the cannabinoid receptor-2 (CB2) by SMM-189, a potent CB2 inverse agonist, on the inhibition of dextran sodium sulfate (DSS) induced colitis. In the present study, we found that SMM-189 effectively attenuated the overall clinical score, reversed colitis-associated pathogenesis, increased body weight and colon length while increasing the expression of CB2 receptors and protein kinase A (PKA) in the colon lamina propria (LPs). We also measured a decrease in the percentage and number of Th17 cells in the spleen, mesenteric lymph nodes (MLNs), and LPs treated with SMM-189 compared to DSS controls. Similarly, the percentage and number of natural killer T (NKT) cells and neutrophils are decreased after SMM-189 treatment. SMM-189 also induces the myeloid-derived suppressor cells (MDSCs) during chronic colitis progression as compared to DSS alone. These findings suggest that SMM-189 ameliorates experimental colitis by inducing CB2 receptors and PKA in the LPs, MDSCs and reduces Th17, NKT cells, and neutrophils from the spleen and LPs. Taken together, these data support the idea that the CB2 inverse agonists, such as SMM-189, may be developed as a novel therapeutic target for IBD. Supported by NIH grant R01 AI140405