New insights into the role of STAT3 in IBD

Origin and Function of Monocytes in Inflammatory Bowel Disease

Inflammatory bowel disease (IBD), including Crohn's disease (CD) and ulcerative colitis (UC), is a chronic disease resulting from the interaction of various factors such as social elements, autoimmunity, genetics, and gut microbiota. Alarmingly, recent epidemiological data points to a surging incidence of IBD, underscoring an urgent imperative: to delineate the intricate mechanisms driving its onset. Such insights are paramount, not only for enhancing our comprehension of IBD pathogenesis but also for refining diagnostic and therapeutic paradigms. Monocytes, significant immune cells derived from the bone marrow, serve as precursors to macrophages (Mφs) and dendritic cells (DCs) in the inflammatory response of IBD. Within the IBD milieu, their role is twofold. On the one hand, monocytes are instrumental in precipitating the disease's progression. On the other hand, their differentiated offsprings, namely moMφs and moDCs, are conspicuously mobilized at inflammatory foci, manifesting either pro-inflammatory or anti-inflammatory actions. The phenotypic spectrum of these effector cells, intriguingly, is modulated by variables such as host genetics and the subtleties of the prevailing inflammatory microenvironment. Notwithstanding their significance, a palpable dearth exists in the literature concerning the roles and mechanisms of monocytes in IBD pathogenesis. This review endeavors to bridge this knowledge gap. It offers an exhaustive exploration of monocytes' origin, their developmental trajectory, and their differentiation dynamics during IBD. Furthermore, it delves into the functional ramifications of monocytes and their differentiated progenies throughout IBD's course. Through this lens, we aspire to furnish novel perspectives into IBD's etiology and potential therapeutic strategies.

H2S-Releasing Versatile Montmorillonite Nanoformulation Trilogically Renovates the Gut Microenvironment for Inflammatory Bowel Disease Modulation

Abnormal activation of the intestinal mucosal immune system, resulting from damage to the intestinal mucosal barrier and extensive invasion by pathogens, contributes to the pathogenesis of inflammatory bowel disease (IBD). Current first-line treatments for IBD have limited efficacy and significant side effects. An innovative H2S-releasing montmorillonite nanoformulation (DPs@MMT) capable of remodeling intestinal mucosal immune homeostasis, repairing the mucosal barrier, and modulating gut microbiota is developed by electrostatically adsorbing diallyl trisulfide-loaded peptide dendrimer nanogels (DATS@PDNs, abbreviated as DPs) onto the montmorillonite (MMT) surface. Upon rectal administration, DPs@MMT specifically binds to and covers the damaged mucosa, promoting the accumulation and subsequent internalization of DPs by activated immune cells in the IBD site. DPs release H2S intracellularly in response to glutathione, initiating multiple therapeutic effects. In vitro and in vivo studies have shown that DPs@MMT effectively alleviates colitis by eliminating reactive oxygen species (ROS), inhibiting inflammation, repairing the mucosal barrier, and eradicating pathogens. RNA sequencing revealed that DPs@MMT exerts significant immunoregulatory and mucosal barrier repair effects, by activating pathways such as Nrf2/HO-1, PI3K-AKT, and RAS/MAPK/AP-1, and inhibiting the p38/ERK MAPK, p65 NF-κB, and JAK-STAT3 pathways, as well as glycolysis. 16S rRNA sequencing demonstrated that DPs@MMT remodels the gut microbiota by eliminating pathogens and increasing probiotics. This study develops a promising nanoformulation for IBD management.

Transcriptional landscape of intestinal environment in DSS-induced ulcerative colitis mouse model

Ulcerative colitis (UC) is a chronic inflammatory disease that targets the colon and has seen an increasing prevalence worldwide. In our pursuit of new diagnostic and therapeutic approaches for UC, we undertook a sequencing of colons from UC mouse models. We focused on analyzing their differentially expressed genes (DEGs), enriching pathways, and constructing protein-protein interaction (PPI) and Competing Endogenous RNA (ceRNA) networks. Our analysis highlighted novel DEGs such as Tppp3, Saa3, Cemip, Pappa, and Nr1d1. These DEGs predominantly play roles in pathways like cytokine-mediated signaling, extracellular matrix organization, extracellular structure organization, and external encapsulating structure organization. This suggests that the UC pathogenesis is intricately linked to the interactions between immune and non-immune cells with the extracellular matrix (ECM). To corroborate our findings, we also verified certain DEGs through quantitative real-time PCR. Within the PPI network, nodes like Stat3, Il1b, Mmp3, and Lgals3 emerged as significant and were identified to be involved in the crucial cytokine-mediated signaling pathway, which is central to inflammation. Our ceRNA network analysis further brought to light the role of the Smad7 Long non-coding RNA (lncRNA). Key MicroRNA (miRNAs) in the ceRNA network were pinpointed as mmu-miR-17-5p, mmu-miR-93-5p, mmu-miR-20b-5p, mmu-miR-16-5p, and mmu-miR-106a-5p, while central mRNAs included Egln3, Plagl2, Sema7a, Arrdc3, and Stat3. These insights imply that ceRNA networks are influential in UC progression and could provide further clarity on its pathogenesis. In conclusion, this research deepens our understanding of UC pathogenesis and paves the way for potential new diagnostic and therapeutic methods. Nevertheless, to solidify our findings, additional experiments are essential to confirm the roles and molecular interplay of the identified DEGs in UC.

2'-Fucosyllactose restores the intestinal mucosal barrier in ulcerative colitis by inhibiting STAT3 palmitoylation and phosphorylation

BACKGROUND & AIMS

2'-Fucosyllactose (2'-FL), the primary constituent of human milk oligosaccharides, has been identified as a potential regulator of inflammation in inflammatory bowel disease. Despite this recognition, the specific mechanisms through which 2'-FL alleviates ulcerative colitis (UC) remain ambiguous. This study seeks to investigate the potential anti-inflammatory properties of 2'-FL concerning intestinal inflammation and uncover the associated mechanisms.

METHODS

C57BL/6J mice were orally administered a daily dose of 500 mg/kg 2'-FL for 11 consecutive days, followed by the induction of colitis using 3 % (wt/vol) dextran sulfate sodium (DSS) for the final 6 days. Subsequently, a comprehensive range of techniques, including an Acyl-biotin exchange assay, fluorescein-isothiocyanate-labeled dextran assay, histopathology, ELISA, quantitative real-time PCR, Western blot, immunofluorescence staining, immunohistochemistry staining, Alcian blue-periodic acid schiff staining, TdT-mediated dUTP nick end labeling, transmission electron microscopy, iTRAQ quantitative proteomics, bioinformatics analysis, and the generation of signal transducer and activator of transcription 3 (STAT3) knockout mice, were employed to explore the relevant molecular mechanisms.

RESULTS

Administration of 2'-FL significantly ameliorated DSS-induced colitis in mice and enhanced the integrity of the intestinal mucosal barrier. 2'-FL downregulated the phosphorylation of STAT3 and inhibited STAT3-related signaling pathways in colon tissues, which, in turn, reduced inflammatory responses. Interestingly, knockdown of STAT3 attenuated the protective effects of 2'-FL, highlighting that 2'-FL-mediated inflammatory attenuation is dependent on STAT3 expression. Additionally, 2'-FL could influence STAT3 activation by modulating the palmitoylation and depalmitoylation of STAT3.

CONCLUSIONS

2'-FL promotes the recovery of the intestinal mucosal barrier and suppresses inflammation in ulcerative colitis by inhibiting the palmitoylation and phosphorylation of STAT3.

Dietary long-chain fatty acids promote colitis by regulating palmitoylation of STAT3 through CD36-mediated endocytosis

The Western diet, characterized by its high content of long-chain fatty acids (LCFAs), is widely recognized as a significant triggering factor for inflammatory bowel disease (IBD). While the link between a high-fat diet and colitis has been observed, the specific effects and mechanisms remain incompletely understood. Our study provides evidence that the diet rich in LCFAs can disrupt the integrity of the intestinal barrier and exacerbate experimental colitis in mice. Mechanistically, LCFAs upregulate the signal transducer and activator of transcription-3 (STAT3) pathway in the inflammatory model, and STAT3 knockout effectively counters the pro-inflammatory effects of LCFAs on colitis. Specifically, palmitic acid (PA), a representative LCFA, enters intestinal epithelial cells via the cluster of differentiation 36 (CD36) pathway and participates in the palmitoylation cycle of STAT3. Inhibiting this cycle using pharmacological inhibitors like 2-Bromopalmitate (2-BP) and ML349, as well as DHHC7 knockdown, has the ability to alleviate inflammation induced by PA. These findings highlight the significant role of dietary LCFAs, especially PA, in the development and progression of IBD. Diet adjustments and targeted modulation offer potential therapeutic strategies for managing this condition. Model of LCFAs involvement in the palmitoylation cycle of STAT3 upon internalization into cells. Following cellular uptake through CD36, LCFAs are converted to palmitoyl-CoA. In the presence of DHHC7, palmitoyl-CoA binds to STAT3 at the C108 site, forming palmitoylated STAT3. Palmitoylation further promotes phosphorylation at the Y705 site of STAT3. Subsequently, palmitoylated STAT3 undergoes depalmitoylation by APT2 and translocates to the nucleus to exert its biological functions.

Clinical Features and Genetic Analysis of Taiwanese Primary Immunodeficiency Patients with Prolonged Diarrhea and Monogenetic Inflammatory Bowel Disease

PURPOSE

Diarrhea lasting longer than 14 days which fails to respond to conventional management is defined as severe and protracted diarrhea and might overlap with inflammatory bowel disease (IBD).

METHODS

The prevalence, associated pathogens, and prognosis of severe and protracted diarrhea without IBD (SD) and with monogenetic IBD (mono-IBD) in primary immunodeficiency patients (PID) were investigated in Taiwan.

RESULTS

A total of 301 patients were enrolled between 2003 and 2022, with predominantly pediatric-onset PID. Of these, 24 PID patients developed the SD phenotype before prophylactic treatment, including Btk (six), IL2RG (four), WASP, CD40L, gp91 (three each), gp47, RAG1 (one each), CVID (two), and SCID (one) without identified mutations. The most detectable pathogens were pseudomonas and salmonella (six each), and all patients improved after approximately 2 weeks of antibiotic and/or IVIG treatments. Six (25.0%) mortalities without HSCT implementation were due to respiratory failure from interstitial pneumonia (3 SCID and 1 CGD), intracranial hemorrhage (WAS), and lymphoma (HIGM). In the mono-IBD group, seventeen patients with mutant TTC7A (2), FOXP3 (2), NEMO (2), XIAP (2), LRBA (1), TTC37 (3), IL10RA (1), STAT1 (1), ZAP70 (1), PIK3CD (1), and PIK3R1 (1) genes failed to respond to aggressive treatments. Nine mono-IBD patients with TTC7A (2), FOXP3 (2), NEMO (2), XIAP (2), and LRBA (1) mutations were fatal in the absence of HSCT. The mono-IBD group had a significantly earlier age of diarrhea onset (1.7 vs 33.3 months, p = 0.0056), a longer TPN duration (34.2 vs 7.0 months, p < 0.0001), a shorter follow-up period (41.6 vs 132.6 months, p = 0.007), and a higher mortality rate (58.9 vs 25.0%, p = 0.012) compared with the SD group.

CONCLUSION

When compared to those with the SD phenotype, the mono-IBD patients had significant early-onset and poor responses to empiric antibiotics, IVIG, and steroids. Anti-inflammatory biologics and suitable HSCT still have the potential to control or even cure the mono-IBD phenotype.

Oxidative stress gene expression, DNA methylation, and gut microbiota interaction trigger Crohn's disease: a multi-omics Mendelian randomization study

BACKGROUND

Oxidative stress (OS) is a key pathophysiological mechanism in Crohn's disease (CD). OS-related genes can be affected by environmental factors, intestinal inflammation, gut microbiota, and epigenetic changes. However, the role of OS as a potential CD etiological factor or triggering factor is unknown, as differentially expressed OS genes in CD can be either a cause or a subsequent change of intestinal inflammation. Herein, we used a multi-omics summary data-based Mendelian randomization (SMR) approach to identify putative causal effects and underlying mechanisms of OS genes in CD.

METHODS

OS-related genes were extracted from the GeneCards database. Intestinal transcriptome datasets were collected from the Gene Expression Omnibus (GEO) database and meta-analyzed to identify differentially expressed genes (DEGs) related to OS in CD. Integration analyses of the largest CD genome-wide association study (GWAS) summaries with expression quantitative trait loci (eQTLs) and DNA methylation QTLs (mQTLs) from the blood were performed using SMR methods to prioritize putative blood OS genes and their regulatory elements associated with CD risk. Up-to-date intestinal eQTLs and fecal microbial QTLs (mbQTLs) were integrated to uncover potential interactions between host OS gene expression and gut microbiota through SMR and colocalization analysis. Two additional Mendelian randomization (MR) methods were used as sensitivity analyses. Putative results were validated in an independent multi-omics cohort from the First Affiliated Hospital of Sun Yat-sen University (FAH-SYS).

RESULTS

A meta-analysis from six datasets identified 438 OS-related DEGs enriched in intestinal enterocytes in CD from 817 OS-related genes. Five genes from blood tissue were prioritized as candidate CD-causal genes using three-step SMR methods: BAD, SHC1, STAT3, MUC1, and GPX3. Furthermore, SMR analysis also identified five putative intestinal genes, three of which were involved in gene-microbiota interactions through colocalization analysis: MUC1, CD40, and PRKAB1. Validation results showed that 88.79% of DEGs were replicated in the FAH-SYS cohort. Associations between pairs of MUC1-Bacillus aciditolerans and PRKAB1-Escherichia coli in the FAH-SYS cohort were consistent with eQTL-mbQTL colocalization.

CONCLUSIONS

This multi-omics integration study highlighted that OS genes causal to CD are regulated by DNA methylation and host-microbiota interactions. This provides evidence for future targeted functional research aimed at developing suitable therapeutic interventions and disease prevention.

Identifying neutrophil-associated subtypes in ulcerative colitis and confirming neutrophils promote colitis-associated colorectal cancer

Background

Ulcerative colitis (UC) is a chronic inflammatory disease of the intestinal mucosa, the incidence of which has increased worldwide. There is still a lack of clear understanding of the pathogenesis of ulcerative colitis that ultimately leads to colitis-associated colorectal cancer.

Method

We download UC transcriptome data from the GEO database and pass the limma package in order to identify differentially expressed genes. Gene Set Enrichment Analysis (GSEA) was used to identify potential biological pathways. We identified immune cells associated with UC by CIBERSORT and Weighted co-expression network analysis (WGCNA). We used validation cohorts and mouse models to verify the expression of the hub genes and the role of neutrophils.

Result

We identified 65 differentially expressed genes in UC samples and healthy controls. GSEA, KEGG, and GO analyses displayed that DEGs were enriched in immune-related pathways. CIBERSORT analysis revealed increased infiltration of neutrophils in UC tissues. The red module, obtained by WGCNA analysis, was considered to be the most relevant module for neutrophils.Based on neutrophil-associated differentially expressed genes, UC patients were classified into two subtypes of neutrophil infiltration. We discovered that the highly neutrophil-infiltrated subtype B of UC patients had a higher risk of developing CAC. Five genes were identified as biomarkers by searching for DEGs between distinct subtypes. Finally, using the mouse model, we determined the expression of these five genes in the control, DSS, and AOM/DSS groups. The degree of neutrophil infiltration in mice and the percentage of MPO and pSTAT3 expression in neutrophils were analyzed by flow cytometry. In the AOM/DSS model, MPO and pSTAT3 expressions were significantly increased.

Conclusions

These findings suggested neutrophils might promote the conversion of UC into CAC. These findings improve our understanding of the pathogenesis of CAC and provide new and more effective insights into the prevention and treatment of CAC.

Comprehensive analysis to identify the influences of SARS-CoV-2 infections to inflammatory bowel disease

Background

Coronavirus disease 2019 (COVID-19) and inflammatory bowel disease (IBD) are both caused by a disordered immune response and have direct and profound impacts on health care services. In this study, we implemented transcriptomic and single-cell analysis to detect common molecular and cellular intersections between COVID-19 and IBD that help understand the linkage of COVID-19 to the IBD patients.

Methods

Four RNA-sequencing datasets (GSE147507, GSE126124, GSE9686 and GSE36807) from Gene Expression Omnibus (GEO) database are extracted to detect mutual differentially expressed genes (DEGs) for IBD patients with the infection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) to find shared pathways, candidate drugs, hub genes and regulatory networks. Two single-cell RNA sequencing (scRNA-eq) datasets (GSE150728, PRJCA003980) are used to analyze the immune characteristics of hub genes and the proportion of immune cell types, so as to find common immune responses between COVID-19 and IBD.

Results

A total of 121 common DEGs were identified among four RNA-seq datasets, and were all involved in the functional enrichment analysis related to inflammation and immune response. Transcription factors-DEGs interactions, miRNAs-DEGs coregulatory networks, and protein-drug interactions were identified based on these datasets. Protein-protein interactions (PPIs) was built and 59 hub genes were identified. Moreover, scRNA-seq of peripheral blood monocyte cells (PBMCs) from COVID-19 patients revealed a significant increase in the proportion of CD14⁺ monocytes, in which 38 of 59 hub genes were highly enriched. These genes, encoding inflammatory cytokines, were also highly expressed in inflammatory macrophages (IMacrophage) of intestinal tissues of IBD patients.

Conclusions

We conclude that COVID-19 may promote the progression of IBD through cytokine storms. The candidate drugs and DEGs-regulated networks may suggest effective therapeutic methods for both COVID-19 and IBD.

From inflammatory bowel disease to colorectal cancer: what's the role of miRNAs?

Inflammatory Bowel Disease (IBD) is a chronic inflammatory disease with relapse and remission periods. Ulcerative colitis and Crohn's disease are two major forms of the disease. IBD imposes a lot of sufferings on the patient and has many consequences; however, the most important is the increased risk of colorectal cancer, especially in patients with Ulcerative colitis. This risk is increased with increasing the duration of disease, thus preventing the progression of IBD to cancer is very important. Therefore, it is necessary to know the details of events contributed to the progression of IBD to cancer. In recent years, the importance of miRNAs as small molecules with 20-22 nucleotides has been recognized in pathophysiology of many diseases, in which IBD and colorectal cancer have not been excluded. As a result, the effectiveness of these small molecules as therapeutic target is hopefully confirmed. This paper has reviewed the related studies and findings about the role of miRNAs in the course of events that promote the progression of IBD to colorectal carcinoma, as well as a review about the effectiveness of some of these miRNAs as therapeutic targets.

Evolution and expression analysis of STAT family members in blunt snout bream (Megalobrama amblycephala)

The Janus kinase/signal transducer and activator of transcription (JAK/STAT) pathway is involved in regulating the body's immunity, cell proliferation, differentiation, and apoptosis. Members of the STAT family have been extensively studied in different mammalian species. However, there are few studies on the STAT family genes in farmed economic fish. In this study, eight STAT genes including STAT1a, STAT1b, STAT2, STAT3, STAT4, STAT5a, STAT5b and STAT6, in blunt snout bream (Megalobrama amblycephala), an economically important fish in China, were identified and characterized. Analyses of gene location, phylogeny and conserved synteny were conducted to infer the evolutionary origin of these STAT family genes. Furthermore, the evolutionary origin model of STATs was constructed based on the 2R hypothesis and teleost genome duplication (TGD) hypothesis, which clarified the evolutionary origin of the eight STATs in blunt snout bream. Besides, expression of the eight STATs was detected in 10 tissues of healthy blunt snout bream, which showed different expression patterns, and all had the highest level in the blood. In addition, expression of the STATs was significantly induced in the spleen, liver, and kidney after infection of Aeromonas hydrophila, suggesting that they play an important role in protecting the host from pathogens. In general, the evolution of cytokine-related genes parallels that of the immune system, which has likely been a main evolutionary driver. Therefore, the evolutionary model of STAT genes, constructed in the non-model organism pioneeringly, may provide some enlightenment for the evolution of the fish STAT family genes and their involvement in the immune function.

Interferon Lambda in the Pathogenesis of Inflammatory Bowel Diseases

Interferon λ (IFN-λ) is critical for host viral defense at mucosal surfaces and stimulates immunomodulatory signals, acting on epithelial cells and few other cell types due to restricted IFN-λ receptor expression. Epithelial cells of the intestine play a critical role in the pathogenesis of Inflammatory Bowel Disease (IBD), and the related type II interferons (IFN-γ) have been extensively studied in the context of IBD. However, a role for IFN-λ in IBD onset and progression remains unclear. Recent investigations of IFN-λ in IBD are beginning to uncover complex and sometimes opposing actions, including pro-healing roles in colonic epithelial tissues and potentiation of epithelial cell death in the small intestine. Additionally, IFN-λ has been shown to act through non-epithelial cell types, such as neutrophils, to protect against excessive inflammation. In most cases IFN-λ demonstrates an ability to coordinate the host antiviral response without inducing collateral hyperinflammation, suggesting that IFN-λ signaling pathways could be a therapeutic target in IBD. This mini review discusses existing data on the role of IFN-λ in the pathogenesis of inflammatory bowel disease, current gaps in the research, and therapeutic potential of modulating the IFN-λ-stimulated response.

PDE9 Inhibitor PF-04447943 Attenuates DSS-Induced Colitis by Suppressing Oxidative Stress, Inflammation, and Regulating T-Cell Polarization

Ulcerative colitis (UC) is a form of inflammatory bowel disease, which manifests as irritation or swelling and sores in the large intestine in a relapsing and remitting manner. In a dextran sulfate sodium sulfate (DSS)-induced UC model in female mice, we found that the levels of cyclic guanosine monophosphate (cGMP) are reduced, while the expression of phosphodiesterase 9A (PDE9A) is highest among all phosphodiesterase (PDEs). Since PDE9 has the highest affinity toward cGMP, we evaluated the selective PDE9 inhibitor PF-04447943 (PF) as a potential candidate for UC treatment. PF has been extensively studies in cognitive function and in sickle cell disease, but not in models for inflammatory bowel disease (IBD). Therefore, we used female C57BL/6 mice treated with 3% DSS alone or co-treated with PF or sulfasalazine (SASP) to study the body weight, colon length, histopathology, and measure superoxide dismutase (SOD), malondialdehyde (MDA), and cGMP level, as well as cytokines such as tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), interleukin-17 (IL-17), interleukin-12/23 (IL-12/23), interleukin-10 (IL-10), and pathways including nuclear factor kappa B (NF-κB), signal transducer and activator of transcription 3 (STAT3), and inflammasome activation. In addition, the number of dendritic cells (DC) and regulatory T cells (Treg cell) was assessed in the spleen, lymph node, and colon using flow cytometry. DSS reduced the number of goblet cells, decreased colon lengths and body weights, all of them were attenuated by PF treatment. It also suppressed the elevated level of inflammatory cytokines and increased level the anti-inflammatory cytokine, IL-10. PF treatment also reduced the DSS-induced inflammation by suppressing oxidative stress, NF-κB, STAT3, and inflammasome activation, by upregulating nuclear factor erythroid 2-related factor 2 (Nrf-2) and its downstream proteins via extracellular signal-regulated kinase (ERK) phosphorylation. Importantly, PF reversed imbalance in Treg/T helper 17 cells (Th17) cells ratio, possibly by regulating dendritic cells and Treg developmental process. In summary, this study shows the protective effect of a PDE9A inhibitor in ulcerative colitis by suppressing oxidative stress and inflammation as well as reversing the Treg/Th17 cells imbalance.

15-Deoxy-△12,14-Prostaglandin J2 Promotes Resolution of Experimentally Induced Colitis

Uncontrolled macrophage functions cause failure to resolve gut inflammation and has been implicated in the pathogenesis of inflammatory bowel disease (IBD). 15-Deoxy-Δ^12,14-prostaglandin J₂ (15d-PGJ₂), one of endogenous lipid mediators formed from arachidonic acid during the inflammatory process, has been reported to terminate inflammation. However, the pro-resolving effect of 15d-PGJ₂ on intestinal inflammation and underlying molecular mechanisms remain largely unknown. In the present study, we examined the effects of 15d-PGJ₂ on the resolution of dextran sulfate sodium (DSS)-induced murine colitis that mimics human IBD. Pharmacologic inhibition of prostaglandin D synthase (PGDS) responsible for the synthesis of 15d-PGJ₂ hampered resolution of inflammation in the colonic mucosa of mice treated with DSS. Notably, intraperitoneal injection of 15d-PGJ₂ accelerated the resolution of experimentally induced colitis. 15d-PGJ₂ treatment reduced the number of neutrophils and M1 macrophages, while it increased the proportion of M2 macrophages. Moreover, 15d-PGJ₂ treated mice exhibited the significantly reduced proportion of macrophages expressing the pro-inflammatory cytokine, IL-6 with concomitant suppression of STAT3 phosphorylation in the colonic mucosa of mice administered 2.5% DSS in drinking water. Taken together, these findings clearly indicate that 15d-PGJ₂, endogenously generated from arachidonic acid by cyclooxygenase-2 and PGDS activities in inflamed tissue, promotes resolution of intestinal colitis.

Xianglian Pill Suppresses Inflammation and Protects Intestinal Epithelial Barrier by Promoting Autophagy in DSS Induced Ulcerative Colitis Mice

Xianglian pill (XLP) is a typical traditional Chinese herbal medicine prescription composed of Coptidis Rhizoma and Aucklandiae Radix. It has been used to treat gastrointestinal disease for centuries. In the present study, the potential mechanisms of XLP in the treatment of ulcerative colitis (UC) were predicted by integrative pharmacology-based approach. Then, the main compounds of XLP were detected by liquid chromatography-mass spectrometry (LC-MS/MS). Finally, we verified the mechanism of XLP in the treatment of UC in a dextran sulfate sodium (DSS) model. C57BL/6 mice were randomly divided into the control group, DSS group, 5-aminosalicylic acid (5-ASA) group which was used as the positive drug control, XLP low, medium, and high dose group, with 10 mice per group. Except for the control group, acute colitis model was induced in the other mice by administering 3% DSS for consecutive 7 days. Mice in 5-ASA and XLP groups were administered with 5-ASA (50 mg/kg) or XLP (0.8, 1.6, 3.2 g/kg) via oral gavage once per day respectively. Body wight and disease activity index were assay during drug intervention. On day 8, all animals in this experiment were sacrificed and colon tissues were collected for analysis after measurement of the length. The results showed that XLP alleviate DSS -induced acute colitis in mice, including inhibition the secretion of pro-inflammatory cytokines, repairing the dysfunction of intestinal epithelial barrier, enhanced autophagy, and blocked the activation of PI3K/Akt/mTOR pathway. Furthermore, inhibiting autophagy by 3-methyladenine attenuated the protective effects of XLP on colitis. The underlying mechanism may be that Xianglian pill promote autophagy by blocking the activation of PI3K/Akt/mTOR signaling pathway.

The interplay of the inhibitory effect of nifuroxazide on NF-κB/STAT3 signaling attenuates acetic acid-induced ulcerative colitis in rats

Ulcerative colitis (UC) is a disease of increased worldwide prevalence. UC progression is associated with serious complications that leave the patient with considerable health burdens. Nifuroxazide is an oral nitrofuran antibiotic used as antidiarrheal medication. The current study places an emphasis on investigating the potential therapeutic effectiveness of nifuroxazide (10 mg/kg) and (20 mg/kg) against acetic acid (AA)-induced UC. Intra-rectal AA induced a significant colonic injury and impairment of colonic biochemical and functional incidences. Nifuroxazide in a dose-dependent manner significantly corrected UC associated injury. Macroscopic scoring of UC, serum lactate dehydrogenase (LDH) activity, C-reactive protein (CRP) titer, colon malondialdehyde (MDA) and total nitric oxide (NOx) contents significantly declined. Meanwhile, serum total antioxidant capacity (TAC) and colon catalase, superoxide dismutase (SOD) and glutathione transferase (GST) activities and reduced glutathione (GSH) concentration significantly increased in a dose-dependent way. Ultimately, histopathological, immunohistochemical and ultramicroscopic analysis of colon specimen revealed significant improvement. To pinpoint the mechanistic pathway underlying the curative effect of nifuroxazide, colon expression of NF-κB, caspase-3 was evaluated along with STAT-3 activation. Nifuroxazide induced a dose-dependent significant suppression of NF-κB and caspase-3 signaling together with STAT3 signaling. In conclusion; nifuroxazide can be proposed as a therapeutic candidate to attenuate UC and its associated symptoms. The potential underlying mechanism involves suppression of NF-κB/STAT-3/caspase- signaling.

Luteolin ameliorates experimental colitis in mice through ERK-mediated suppression of inflammation, apoptosis and autophagy

Ulcerative colitis (UC) is a chronic inflammatory disease with increasing incidence and prevalence worldwide. Currently used treatments of UC are unsatisfactory, while natural bioactive compounds are considered to be emerging therapeutic agents. Luteolin (Lut) is a natural compound with beneficial effects in a variety of diseases, however, its effect in UC has been poorly studied. In this study we investigated the effect of Lut in posttreatment and cotreatment of dextran sulfate sodium (DSS)-induced experimental colitis in mice. In addition, the role of extracellular signal-regulated kinases 1/2 (ERK1/2) in the mechanism of action of Lut in experimental colitis was investigated using the ERK inhibitor PD0325901. Lut attenuated symptoms of DSS-induced colitis in mice, ameliorated colon tissue damage and reduced inflammation, apoptosis and autophagy. The effect was more pronounced if Lut was administered simultaneously with DSS. The administration of ERK inhibitor exacerbated DSS-induced colitis symptoms and prevented the protective effects of Lut. The results provide new mechanistic details underlying the anti-inflammatory, anti-apoptotic and anti-autophagic effects of Lut through the activation of the ERK signaling pathway. This suggested that Lut can be used as a novel therapeutic candidate in the treatment of UC or could be used as a supplement to existing therapy.

Differential regulation of JAK/STAT-signaling in patients with ulcerative colitis and Crohn’s disease

In 2018, the pan-Janus kinase (JAK) inhibitor tofacitinib was launched for the treatment of ulcerative colitis (UC). Although tofacitinib has proven efficacious in patients with active UC, it failed in patients with Crohn’s disease (CD). This finding strongly hints at a different contribution of JAK signaling in both entities. Here, we review the current knowledge on the interplay between the JAK/signal transducer and activator of transcription (STAT) pathway and inflammatory bowel diseases (IBD). In particular, we provide a detailed overview of the differences and similarities of JAK/STAT-signaling in UC and CD, highlight the impact of the JAK/STAT pathway in experimental colitis models and summarize the published evidence on JAK/STAT-signaling in immune cells of IBD as well as the genetic association between the JAK/STAT pathway and IBD. Finally, we describe novel treatment strategies targeting JAK/STAT inhibition in UC and CD and comment on the limitations and challenges of the new drug class.

Dietary polyacetylene falcarinol upregulated intestinal heme oxygenase-1 and modified plasma cytokine profile in late phase lipopolysaccharide-induced acute inflammation in CB57BL/6 mice

Unlike polyphenols, which are widely available in the diet, polyacetylenes are available only from the Apiaceae family vegetables, including carrot, parsnip, fennel, celery, and many herbs (parsley, lovage, etc). The aim of this study was to investigate the hypothesis that polyacetylene falcarinol (FA) reduces intestinal inflammation and examine its similarity of effect to isothiocyanate R-sulforaphane during the late phase of acute inflammation. To this end, 3-month-old male CB57BL/6 mice were fed twice daily for 1 week with 5 mg/kg of FA, sulforaphane, or vehicle before receiving an intraperitoneal injection of 5 mg/kg endotoxin (lipopolysaccharide [LPS]) to induce modest acute inflammation. The expression of intestinal and hepatic heme oxygenase-1 at the mRNA and protein levels, circulating cytokines, as well as intestinal and mesenteric n-6 and n-3 fatty acid lipid mediators was compared 24 hours after LPS administration to examine its effects on the late phase of inflammation. Intestinal nuclear factor (erythroid-derived 2)-like 2 target enzyme heme oxygenase-1 was upregulated 8.42-fold at the mRNA level and 10.7-fold at the protein level by FA-supplemented diet. However, the FA-supplemented diet produced a unique type-2 plasma cytokine skew after LPS treatment. Plasma cytokines interleukin (IL)-4, IL-13, IL-9, and IL-10 were upregulated, reflecting the cytokine profile of reduced type 1 inflammation. A detailed lipidomic analysis of n-6 and n-3 fatty acid pro- and anti-inflammatory pathways in the mesentery and intestinal mucosa showed that FA diet was more similar to the control groups than to other LPS treated groups. In this study, we demonstrated that FA-supplemented diet produced a unique immunomodulatory effect not observed with sulforaphane in late phases of inflammation. These results support the hypothesis that FA may have role as a dietary immunosuppressant in patients with inflammatory gastrointestinal as well as other inflammatory disorders that may be alleviated by increasing consumption of carrot or other FA-containing food sources.

Costunolide improved dextran sulfate sodium-induced acute ulcerative colitis in mice through NF-κB, STAT1/3, and Akt signaling pathways

Costunolide (CTL) is the major sesquiterpene lactone from Radix Aucklandiae, which is widely used on the treatment of gastrointestinal diseases. However, the therapeutic effect of costunolide in ulcerative colitis (UC) is still unknown. Herein, we sought to evaluate the therapeutic effects and underlying mechanisms of costunolide on UC. ICR mice were intraperitoneally administered with costunolide (10 mg/kg) for 10 days. Beginning on the 4th day of drug administration, acute colitis was induced by feeding 4% dextran sulfate sodium (DSS) for additional 7 days. Costunolide markedly attenuated DSS-induced body weight loss, colonic shortening, elevation in disease activity index, and pathological damage of colon, and decreased the number of CD4⁺ T cells in colon tissues. Furthermore, costunolide significantly inhibited myeloperoxidase (MPO) activity and nitric oxide (NO) level in colon tissues in DSS-exposed mice. Meanwhile, costunolide also suppressed DSS-induced expression of induced nitric oxide synthase (iNOS), interleukin-1β (IL-1β), IL-6, tumor necrosis factor-α (TNF-α), and interferon-γ (IFN-γ) in both mRNA and protein levels. Mechanistically, costunolide repressed the phosphorylation of nuclear factor kappa-B (NF-κB) p65 and degradation of inhibitor of NF-κB (IκB), as well as the excessive activation of signal transducers and activators of transcription 1/3 (STAT1/3) and serine/threonine protein kinase Akt (Akt) in colon tissues in DSS-challenged mice. These findings successfully demonstrated that costunolide ameliorated DSS-induced murine acute colitis by suppressing inflammation through inactivation of NF-κB, STAT1/3, and Akt pathways. These results also suggested that costunolide may be a potential therapeutic agent for the treatment of acute UC.

SUMOylation pathway alteration coupled with downregulation of SUMO E2 enzyme at mucosal epithelium modulates inflammation in inflammatory bowel disease

Post-translational modification pathways such as SUMOylation are integral to all cellular processes and tissue homeostasis. We investigated the possible involvement of SUMOylation in the epithelial signalling in Crohn's disease (CD) and ulcerative colitis (UC), the two major forms of inflammatory bowel disease (IBD). Initially in a murine model of IBD, induced by dextran–sulfate–sodium (DSS mice), we observed inflammation accompanied by a lowering of global SUMOylation of colonic epithelium. The observed SUMOylation alteration was due to a decrease in the sole SUMO E2 enzyme (Ubc9). Mass-spectrometric analysis revealed the existence of a distinct SUMOylome (SUMO-conjugated proteome) in DSS mice with alteration of key cellular regulators, including master kinase Akt1. Knocking-down of Ubc9 in epithelial cells resulted in dramatic activation of inflammatory gene expression, a phenomenon that acted via reduction in Akt1 and its SUMOylated form. Importantly, a strong decrease in Ubc9 and Akt1 was also seen in endoscopic biopsy samples (N = 66) of human CD and UC patients. Furthermore, patients with maximum disease indices were always accompanied by severely lowered Ubc9 or SUMOylated-Akt1. Mucosal tissues with severely compromised Ubc9 function displayed higher levels of pro-inflammatory cytokines and compromised wound-healing markers. Thus, our results reveal an important and previously undescribed role for the SUMOylation pathway involving Ubc9 and Akt1 in modulation of epithelial inflammatory signalling in IBD.

Catestatin Regulates Epithelial Cell Dynamics to Improve Intestinal Inflammation

Ulcerative colitis (UC) is characterized by aberrant regulation of tight junctions (TJ), signal transducer and activator of transcription 3 (STAT3), and interleukin (IL)-8/18, which lead to intestinal barrier defects. Catestatin (CST), an enterochromaffin-derived peptide, regulates immune communication and STAT-3 in the inflamed intestine. Here, we investigated the effects of CST during the development of inflammation using human biopsies from patients with active UC, human colonic epithelial cells (Caco2), and an experimental model of UC (dextran sulfate sodium [DSS]-colitis). In UC patients, the protein and mRNA level of CST was significantly decreased. Colonic expression of CST showed a strong positive linear relationship with TJ proteins and STAT3, and a strong negative correlation with IL-8 and IL-18. Intra-rectal administration of CST reduced the severity of experimental colitis, IL-18 colonic levels, maintained TJ proteins and enhanced the phosphorylation of STAT3. CST administration increased proliferation, viability, migration, TJ proteins, and p-STAT3 levels, and reduced IL-8 &amp; IL-18 in LPS- &amp; DSS-induced Caco2 cell epithelial injury, and the presence of STAT-3 inhibitor abolished the beneficial effect of CST. In inflammatory conditions, we conclude that CST could regulate intestinal mucosal dynamic via a potential STAT3-dependent pathway that needs to be further defined. Targeting CST in intestinal epithelial cells (IECs) should be a promising therapeutic approach such as when intestinal epithelial cell homeostasis is compromised in UC patients.

Resveratrol and inflammatory bowel disease

Inflammatory bowel disease (IBD) is a chronic inflammatory disease of the gastrointestinal tract, comprising ulcerative colitis (UC) and Crohn's disease (CD). Progression of IBD leads to long-term impairment of intestinal structure and function. The pathogenesis of IBD is complex, involving environmental, immunological, genetic, microbial, and psychological factors. The conventional therapies and many existing biopharmaceuticals for IBD have limited efficacy or adverse effects. As a promising safe and effective therapy for IBD, resveratrol has been studied widely, as it has shown anti-inflammatory and antioxidant activity. Resveratrol's mechanism of action involves multiple immune responses and signaling pathways; it is absorbed quickly and metabolized into various derivatives. However, the poor water solubility and low bioavailability of resveratrol limit its clinical applications. Further research should attempt to improve the stability and oral bioavailability of resveratrol by modification and various delivery systems.

Novel Mutations of the Tetratricopeptide Repeat Domain 7A Gene and Phenotype/Genotype Comparison

The gastrointestinal tract contains the largest lymphoid organ to react with pathogenic microorganisms and suppress excess inflammation. Patients with primary immunodeficiency diseases (PIDs) can suffer from refractory diarrhea. In this study, we present two siblings who began to suffer from refractory diarrhea with a poor response to aggressive antibiotic and immunosuppressive treatment after surgical release of neonatal intestinal obstruction. Their lymphocyte proliferation was low, but superoxide production and IL-10 signaling were normal. Candidate genetic approach targeted to genes involved in PIDs with inflammatory bowel disease (IBD)-like manifestation was unrevealing. Whole-genome sequencing revealed novel heterozygous mutations Glu75Lys and nucleotide 520–521 CT deletion in the tetratricopeptide repeat domain 7A (TTC7A) gene. A Medline search identified 49 patients with TTC7A mutations, of whom 20 survived. Their phenotypes included both multiple intestinal atresia (MIA) and combined T and/or B immunodeficiency (CID) in 16, both IBD and CID in 14, isolated MIA in 8, MIA, IBD, and CID complex in 8, and isolated IBD in 3. Of these 98 mutant alleles over-through the coding region clustering on exon 2 (40 alleles), exon 7 (12 alleles), and exon 20 (10 alleles), 2 common hotspot mutations were c.211 G>A (p.E71K in exon 2) in 26 alleles and AAGT deletion in exon 7 (+3) in 10 alleles. Kaplan–Meier analysis showed that those with biallelic missense mutations (p = 0.0168), unaffected tetratricopeptide repeat domains (p = 0.0311), and developing autoimmune disorders (p = 0.001) had a relatively better prognosis. Hematopoietic stem cell transplantation (HSCT) restored immunity and seemed to decrease the frequency of infections; however, refractory diarrhea persisted. Clinical improvement was reported upon intestinal and liver transplantation in a child with CID and MIA of unknown genetic etiology. In conclusion, patients with TTC7A mutations presenting with the very early onset of refractory diarrhea had limit improvement by HSCT or/and tailored immunosuppressive therapy in the absence of suitable intestine donors. We suggest that MIA–CID–IBD disorder caused by TTC7A mutations should also be included in the PID classification of “immunodeficiencies affecting cellular and humoral immunity” to allow for prompt recognition and optimal treatment.

A Nationwide Study of Severe and Protracted Diarrhoea in Patients with Primary Immunodeficiency Diseases

Diarrhoea lasting longer than 14 days and failing to respond to conventional management is defined as severe and protracted diarrhoea (SD). In this study, we investigated the prevalence, pathogens and prognosis of SD in primary immunodeficiency diseases (PIDs). Among 246 patients with predominantly paediatric-onset PIDs from 2003–2015, 21 [Btk (six), IL2RG (four), WASP, CD40L, gp91 (three each), gp47, RAG2 (one each)] and five [CVID (four), SCID (one)] without identified mutations had SD before prophylactic treatment. Detectable pathogens included pseudomonas, salmonella (six each), E. coli, cytomegalovirus, coxsackie virus and cryptosporidium (one each), all of whom improved after a mean 17 days of antibiotics and/or IVIG treatment. Seven (7/26; 27.0%) patients died [respiratory failure (four), lymphoma, sepsis and intracranial haemorrhage (one each)]. The patients with WAS, CGD and CD40L and SD had a higher mortality rate than those without. Another five males with mutant XIAP, STAT1, FOXP3 (one each) and STAT3 (two) had undetectable-pathogenic refractory diarrhoea (RD) that persisted >21 days despite aggressive antibiotic/steroid treatment and directly resulted in mortality. For the patients with RD without anti-inflammatory optimization, those with mutant XIAP and FOXP3 died of Crohn’s-like colitis and electrolyte exhaustion in awaiting transplantation, while transplantation cured the STAT1 patient.

Loss of T-cell protein tyrosine phosphatase in the intestinal epithelium promotes local inflammation by increasing colonic stem cell proliferation

T-cell protein tyrosine phosphatase (TC-PTP) has a critical role in the development of the immune system and has been identified as a negative regulator of inflammation. Single-nucleotide polymorphisms in the TC-PTP locus have been associated with increased susceptibility to inflammatory bowel diseases (IBDs) in patients. To further understand how TC-PTP is related to IBDs, we investigated the role of TC-PTP in maintaining the intestinal epithelial barrier using an in vivo genetic approach. Intestinal epithelial cell (IEC)-specific deletion of TC-PTP was achieved in a mouse model at steady state and in the context of dextran sulphate sodium (DSS)-induced colitis. Knockout (KO) of TC-PTP in IECs did not result in an altered intestinal barrier. However, upon DSS treatment, IEC-specific TC-PTP KO mice displayed a more severe colitis phenotype with a corresponding increase in the immune response and inflammatory cytokine profile. The absence of TC-PTP caused an altered turnover of IECs, which is further explained by the role of the tyrosine phosphatase in colonic stem cell (CoSC) proliferation. Our results suggest a novel role for TC-PTP in regulating the homeostasis of CoSC proliferation. This supports the protective function of TC-PTP against IBDs, independently of its previously demonstrated role in intestinal immunity.

Nicotine protects against DSS colitis through regulating microRNA-124 and STAT3

Although it is generally believed that nicotine accounts for the beneficial effect of smoking on ulcerative colitis, the underlying mechanisms remain not well understood. Our previous finding that nicotine inhibits inflammatory responses through inducing miR-124 prompted us to ask whether the miRNA is involved in the protective action of nicotine against UC. Our present study found that miR-124 expression is upregulated in colon tissues from UC patients and DSS colitis mice. Nicotine treatment further augmented miR-124 expression in lymphocytes isolated from human ulcerative colonic mucosa and ulcerative colon tissues from DSS mice, both in infiltrated lymphocytes and epithelial cells. Moreover, knockdown of miR-124 significantly diminished the beneficial effect of nicotine on murine colitis and IL-6-treated Caco-2 colon epithelial cells. Further analysis indicated that nicotine inhibited STAT3 activation in vivo and in IL-6 treated Caco-2 cells and Jurkat human T lymphocytes, in which miR-124 knockdown led to increased activation of STAT3. Blocking STAT3 activity alone is beneficial for DSS colitis and also abolished nicotine's protective effect in this model. These data indicate that nicotine exerts its protective action in UC through inducing miR-124 and inhibiting STAT3, and suggest that the miR-124/STAT3 system is a potential target for the therapeutic intervention of UC.

KEY MESSAGE

Nicotine upregulates miR-124 expression in ulcerative colon tissues and cells. MiR-124 is required for the protective role of nicotine in DSS colitis mice and epithelial cells. The protective effect of nicotine in murine DSS colitis depends on blocking STAT3 activation. MiR-124 mediates the inhibitory role of nicotine on STAT3/p-STAT3. Targeting miR-124 and STAT3 represents a novel approach for treating ulcerative colitis.

Bilberry-derived anthocyanins prevent IFN-γ-induced pro-inflammatory signalling and cytokine secretion in human THP-1 monocytic cells

BACKGROUND/AIMS

Anthocyanins are plant-derived dietary components that are highly abundant, for example, in bilberries. We have previously demonstrated that anthocyanins exert anti-inflammatory properties in mouse colitis models and ameliorate disease activity in ulcerative colitis patients. Here, we studied the molecular mechanisms through which anthocyanin-containing bilberry extract (BE) exerts anti-inflammatory effects in human monocytic THP-1 cells.

METHODS

THP-1 cells were pre-incubated with BE 20 min prior to TNF-α or IFN-γ (100 ng/ml each) stimulation. Signalling protein activation was studied by Western blotting, mRNA expression by quantitative PCR and cytokine secretion by ELISA.

RESULTS

IFN-γ-induced phosphorylation of STAT1 and STAT3 was significantly reduced by BE co-treatment. Consequently, levels of mRNA expression and/or cytokine secretion of MCP-1, IL-6, TNF-α, ICAM-1, and T-bet were lower with BE co-treatment. In contrast, BE enhanced TNF-α-mediated p65-NF-κB phosphorylation but reduced ERK1/2 phosphorylation. BE co-treatment further increased TNF-α-induced mRNA expression and secretion of NF-κB target genes, such as IL-6, IL-8, and MCP-1, while mRNA levels of ICAM-1 were reduced.

CONCLUSIONS

BE co-treatment reduced IFN-γ-induced signal protein activation, pro-inflammatory gene expression, and cytokine secretion, whereas it enhanced TNF-α-induced responses. These findings suggest a distinct role for anthocyanins in modulating inflammatory responses that need to be further studied to fully understand anthocyanin-mediated effects.

6-Mercaptopurine reduces macrophage activation and gut epithelium proliferation through inhibition of GTPase Rac1

BACKGROUND

Inflammatory bowel disease is characterized by chronic intestinal inflammation. Azathioprine and its metabolite 6-mercaptopurine (6-MP) are effective immunosuppressive drugs that are widely used in patients with inflammatory bowel disease. However, established understanding of their immunosuppressive mechanism is limited. Azathioprine and 6-MP have been shown to affect small GTPase Rac1 in T cells and endothelial cells, whereas the effect on macrophages and gut epithelial cells is unknown.

METHODS

Macrophages (RAW cells) and gut epithelial cells (Caco-2 cells) were activated by cytokines and the effect on Rac1 signaling was assessed in the presence or absence of 6-MP.

RESULTS

Rac1 is activated in macrophages and epithelial cells, and treatment with 6-MP resulted in Rac1 inhibition. In macrophages, interferon-γ induced downstream signaling through c-Jun-N-terminal Kinase (JNK) resulting in inducible nitric oxide synthase (iNOS) expression. iNOS expression was reduced by 6-MP in a Rac1-dependent manner. In epithelial cells, 6-MP efficiently inhibited tumor necrosis factor-α-induced expression of the chemokines CCL2 and interleukin-8, although only interleukin-8 expression was inhibited in a Rac1-dependent manner. In addition, activation of the transcription factor STAT3 was suppressed in a Rac1-dependent fashion by 6-MP, resulting in reduced proliferation of the epithelial cells due to diminished cyclin D1 expression.

CONCLUSIONS

These data demonstrate that 6-MP affects macrophages and gut epithelial cells beneficially, in addition to T cells and endothelial cells. Furthermore, mechanistic insight is provided to support development of Rac1-specific inhibitors for clinical use in inflammatory bowel disease.

Oral treatment with SEW2871, a sphingosine-1-phosphate type 1 receptor agonist, ameliorates experimental colitis in interleukin-10 gene deficient mice

SEW2871, a selective sphingosine-1-phosphate type 1 receptor (S1P1) agonist, has been shown to be effective in protecting kidneys against ischaemia-reperfusion injury by reducing CD4(+) T cell infiltration in mice. However, the effects of SEW2871 on colitis remain unclear. The aim of this study was to investigate the effects of SEW2871 on established colitis in interleukin (IL)-10 gene-deficient (IL-10(-/-)) mice, a murine model of Crohn's disease (CD). SEW2871 was administered by gavage at a dose of 20 mg/kg/day for 2 weeks to IL-10(-/-) mice. Severity of colitis, serum amyloid A, tissue myeloperoxidase (MPO), T cells in blood and colon lamina propria (LP) and proinflammatory cytokine productions were evaluated. Furthermore, the phospho-signal transducer and activator of transcription (STAT)-3 (p-STAT-3) expression in lymphocytes isolated from colon LP was also assessed. The 2-week administration of SEW2871 ameliorated established colitis in IL-10(-/-) mice, associated with a reduction of serum amyloid A concentration, a decreased colon MPO concentration, a depletion of the peripheral CD4(+) CD45(+) T cells and a reduction of the homing of T cells into colon LP. Moreover, typical cytokines of T helper type 1 (Th1) and Th17 cells and p-STAT-3 expression were also suppressed by SEW2871 treatment. SEW2871 treatment ameliorates established experimental colitis in IL-10(-/-) mice, which may provide a new therapeutic approach for human CD therapy.

Association between STAT3 gene polymorphisms and Crohn's disease susceptibility: a case-control study in a Chinese Han population

Background

Crohn’s disease (CD) is an immune-related disease with genetic predisposition. This study aimed to investigate the association of three polymorphisms in the signal transducer and activator of transcription 3 (STAT3) gene with CD risk in a Chinese population.

Methods

We conducted a hospital-based case–control study involving 232 CD patients and 272 controls. Genotyping was performed using polymerase chain reaction with sequence-specific primer method. Statistical analyses were conducted using logistic regression and genotype risk scoring.

Results

Significant differences were found between patients and controls in allele/genotype distributions of rs744166 (Pallele = 0.0008; Pgenotype = 0.003) and allele distributions of rs4796793 (P = 0.03). The risk for CD associated with the rs744166-A mutant allele decreased by 37% [95% confidence interval (CI): 0.48–0.83] under the additive model, 39% (95% CI: 0.43–0.81) under the dominant model and 57% (95% CI: 0.24–0.77) under the recessive model. Carriers of the rs4796793-G mutant allele exhibited 25% (95% CI: 0.58–0.98; P = 0.03) and 47% (95% CI: 0.30–0.95) decreased risks of developing CD under the additive and recessive models, respectively.

Conclusions

STAT3 rs744166 and rs4796793 polymorphisms may be associated with CD occurrence and used as a predictive factor of CD in Chinese Han populations.

Virtual Slides

The virtual slide(s) for this article can be found here: http://diagnosticpathology.slidepath.com/webViewer.php?snapshotId=1297687014

Systematic identification of core transcription factors mediating dysregulated links bridging inflammatory bowel diseases and colorectal cancer

Accumulating evidence shows a tight link between inflammation and cancer. However, comprehensive identification of pivotal transcription factors (i.e., core TFs) mediating the dysregulated links remains challenging, mainly due to a lack of samples that can effectively reflect the connections between inflammation and tumorigenesis. Here, we constructed a series of TF-mediated regulatory networks from a large compendium of expression profiling of normal colonic tissues, inflammatory bowel diseases (IBDs) and colorectal cancer (CRC), which contains 1201 samples in total, and then proposed a network-based approach to characterize potential links bridging inflammation and cancer. For this purpose, we computed significantly dysregulated relationships between inflammation and their linked cancer networks, and then 24 core TFs with their dysregulated genes were identified. Collectively, our approach provides us with quite important insight into inflammation-associated tumorigenesis in colorectal cancer, which could also be applied to identify functionally dysregulated relationships mediating the links between other different disease phenotypes.

Transcriptomics to study the effect of a Mediterranean-inspired diet on inflammation in Crohn's disease patients

Background

Inflammation is an essential immune response; however, chronic inflammation results in disease including Crohn's disease. Therefore, reducing the inflammation can yield a significant health benefit, and one way to achieve this is through diet. We developed a Mediterranean-inspired anti-inflammatory diet and used this diet in a 6-week intervention in a Crohn's disease population. We examined changes in inflammation and also in the gut microbiota. We compared the results of established biomarkers, C-reactive protein and the micronuclei assay, of inflammation with results from a transcriptomic approach.

Results

Data showed that being on our diet for 6 weeks was able to reduce the established biomarkers of inflammation. However, using transcriptomics, we observed significant changes in gene expression. Although no single gene stood out, the cumulative effect of small changes in many genes combined to have a beneficial effect. Data also showed that our diet resulted in a trend of normalising the microbiota.

Conclusions

This study showed that our Mediterranean-inspired diet appeared to benefit the health of people with Crohn's disease. Our participants showed a trend for reduced markers of inflammation and normalising of the microbiota. The significant changes in gene expression after 6 weeks highlighted the increased sensitivity of using transcriptomics when compared to the established biomarkers and open up a new era of dietary intervention studies.

Why interleukin-10 supplementation does not work in Crohn’s disease patients

Inflammatory bowel diseases (IBD) such as Crohn’s disease (CD) or ulcerative colitis are chronic intestinal disorders, which are on the increase in “Westernised” countries. IBD can be caused by both genetic and environmental factors. Interleukin-10 (IL-10) is an immunoregulatory cytokine that has been identified as being involved in several diseases including IBD. Studies have shown that polymorphisms in the promoter region reduce serum levels of IL-10 and this reduction has been associated with some forms of IBD. Mouse models have shown promising results with IL-10 supplementation, as such IL-10 supplementation has been touted as being a possible alternative treatment for CD in humans. Clinical trials have shown that recombinant human IL-10 is safe and well tolerated up to a dose of 8 μg/kg. However, to date, the results of the clinical trials have been disappointing. Although CD activity was reduced as measured by the CD activity index, IL-10 supplementation did not result in significantly reduced remission rates or clinical improvements when compared to placebo. This review discusses why IL-10 supplementation is not effective in CD patients currently and what can be addressed to potentially make IL-10 supplementation a more viable treatment option in the future. Based on the current research we conclude that IL-10 supplementation is not a one size fits all treatment and if the correct population of patients is chosen then IL-10 supplementation could be of benefit.

Involvement of JAK/STAT signaling in the pathogenesis of inflammatory bowel disease

The Janus kinase/signal transducer and activator of transcription (JAK/STAT) pathway constitute the fulcrum in many vital cellular processes, including cell growth, differentiation, proliferation, and regulatory immune functions. Various cytokines, growth factors, and protein tyrosine kinases communicate through the JAK/STAT pathway and regulate the transcription of numerous genes. In addition to their critical roles in a plethora of key cellular activities, the JAK/STAT signaling pathways also have been implicated in the pathogenesis of several diseases, including inflammatory bowel disease (IBD), especially since a JAK inhibitor recently has been shown to be effective in the treatment of ulcerative colitis. The aim of this review is to highlight the recent findings on the regulatory mechanism of JAK/STAT signaling pathways and to reveal the evolving comprehension of their interface which might be of interest for clinicians involved in IBD therapy. Further, it is described how these signaling pathways have been exploited for the development of promising novel JAK inhibitors with anti-inflammatory effects verified in clinical trials.

Increased suppressor of cytokine signaling-3 expression predicts mucosal relapse in ulcerative colitis

BACKGROUND

Most biomarkers predicting mucosal relapse of ulcerative colitis (UC) patients in clinical remission represent low levels of mucosal inflammation. Since SOCS3 expression may increase the vulnerability of intestinal epithelial cells (IECs) to various insults, we investigated whether its expression predicts mucosal relapse in UC patients in clinical remission without any signs of mucosal inflammation.

METHODS

UC patients (n = 32) in clinical, endoscopic, and histological remission were followed up for 9 years. IEC expression of SOCS3, p-STAT3, and p-STAT1 were assessed with biopsies from the baseline colonoscopy, last colonoscopy before relapse, and colonoscopy at relapse. Clinical data, endoscopy, and histology reports were collected from patient charts.

RESULTS

Twenty-six (81%) patients had histological relapse, 19 (59%) developed an endoscopic relapse, and 17 (53%) had a clinical relapse during follow-up. SOCS3 expression at first colonoscopy during remission correlated with shorter time to histological, endoscopic, and clinical relapse. SOCS3 expression was increased at the last colonoscopy before relapse, approaching relapse levels, whereas p-STAT3 expression was low during the entire remission. A positive correlation between IEC SOCS3 and its inducer p-STAT1 was shown.

CONCLUSIONS

SOCS3 IEC expression during remission may be useful in predicting mucosal relapse in patients without any signs of mucosal inflammation. These data strengthen our hypothesis that SOCS3 contributes to enhanced vulnerability of IEC during remission. Thus, SOCS3 levels during remission may function as a therapeutic target for clinical monitoring and early induction of mucosal healing.

Beneficial effect of shikonin on experimental colitis induced by dextran sulfate sodium in BALB/c mice

The naphthoquinone shikonin, a major component of the root of Lithospermum erythrorhizon, now is studied as an anti-inflammatory agent in the treatment of ulcerative colitis (UC). Acute UC was induced in Balb/C mice by oral administration of 5% dextran sodium sulfate (DSS). The disease activity index was evaluated, and a histologic study was carried out. Orally administered shikonin reduces induced UC in a dose-dependent manner, preventing the shortening of the colorectum and decreasing weight loss by 5% while improving the appearance of feces and preventing bloody stools. The disease activity index score was much lower in shikonin-treated mice than in the colitic group, as well as the myeloperoxidase activity. The expression of cyclooxygenase-2 was reduced by 75%, activation of NF-κB was reduced by 44%, and that of pSTAT-3 by 47%, as well as TNF-α, IL-1β, and IL-6 production. Similar results were obtained in primary macrophages culture. This is the first report of shikonin's ability to attenuate acute UC induced by DSS. Shikonin acts by blocking the activation of two major targets: NF-κB and STAT-3, and thus constitutes a promising potential therapeutic agent for the management of the inflammatory bowel disease.

STAT1, STAT6 and adenosine 3',5'-cyclic monophosphate (cAMP) signaling drive SOCS3 expression in inactive ulcerative colitis

Ulcerative colitis (UC) is a chronic disease associated with long periods of quiescent disease followed by fulminant exacerbation. Imminent relapse in UC is associated with high mucosal expression of suppressor of cytokine signaling 3 (SOCS3); hence, knowledge of the mechanisms driving mucosal SOCS3 expression may provide important clues as to rational therapy. Thus, here we aim to characterize the molecular forces driving SOCS3 expression in the mucosal compartment, focusing on druggable pathways. The colon epithelial cell line Caco-2 was stimulated with interferon (IFN)-γ, interleukin (IL)-4 or prostaglandin E(2) (PGE(2)) to allow correlations between SOCS3 expression with signal transducer and activator of transcription 1 (STAT1), STAT6 and adenosine 3',5'-cyclic monophosphate (cAMP) signaling, respectively. The physiological relevance of the findings obtained was assessed by immunohistochemical staining for the activated forms of STAT1, STAT6, protein kinase A (PKA)-Cγ and cAMP response element-binding protein (CREB) in biopsies from inactive UC patients and controls. Stimulation with IFN-γ, IL-4 or PGE(2) induced activation of STAT1, STAT6 and cAMP, respectively, in colonic cells, without any signs of concomitant STAT3 activation. Forced activation of all these signaling pathways was sufficient for SOCS3 expression. Biopsies from patients with inactive UC showed significant increase of phosphorylated STAT1 (p-STAT1) (p < 0.0001), p-STAT6 (p = 0.0001), p-PKA-Cγ (p = 0.0003) and p-CREB (p = 0.0025) expression compared with controls. STAT3-independent SOCS3 induction in inactive UC involves multiple proinflammatory signaling pathways and contradicts the usefulness of pathway-specific antiinflammatory drugs for preventing relapse. Our findings suggest that broad-spectrum antiinflammatory drugs are essential to counteract increases in SOCS3 expression and exacerbation of disease. Our results highlight the multifactorial nature of the factors that cause exacerbation in UC.