Tumour necrosis factor superfamily members in the pathogenesis of inflammatory bowel disease

Generally-healthy individuals with aberrant bowel movement frequencies show enrichment for microbially-derived blood metabolites associated with reduced kidney function

Bowel movement frequency (BMF) has been linked to changes in the composition of the human gut microbiome and to many chronic conditions, like metabolic disorders, neurodegenerative diseases, chronic kidney disease (CKD), and other intestinal pathologies like irritable bowel syndrome and inflammatory bowel disease. Lower BMF (constipation) can lead to compromised intestinal barrier integrity and a switch from saccharolytic to proteolytic fermentation within the microbiota, giving rise to microbially-derived toxins that may make their way into circulation and cause damage to organ systems. However, the connections between BMF, gut microbial metabolism, and the early-stage development and progression of chronic disease remain underexplored. Here, we examined the phenotypic impact of BMF variation in a cohort of generally-healthy, community dwelling adults with detailed clinical, lifestyle, and multi-omic data. We showed significant differences in microbially-derived blood plasma metabolites, gut bacterial genera, clinical chemistries, and lifestyle factors across BMF groups that have been linked to inflammation, cardiometabolic health, liver function, and CKD severity and progression. We found that the higher plasma levels of 3-indoxyl sulfate (3-IS), a microbially-derived metabolite associated with constipation, was in turn negatively associated with estimated glomerular filtration rate (eGFR), a measure of kidney function. Causal mediation analysis revealed that the effect of BMF on eGFR was significantly mediated by 3-IS. Finally, we identify self-reported diet, lifestyle, and psychological factors associated with BMF variation, which indicate several common-sense strategies for mitigating constipation and diarrhea. Overall, we suggest that aberrant BMF is an underappreciated risk factor in the development of chronic diseases, even in otherwise healthy populations.

The NF-κB signaling system in the immunopathogenesis of inflammatory bowel disease

Inflammatory bowel disease (IBD) is an idiopathic, chronic condition characterized by episodes of inflammation in the gastrointestinal tract. The nuclear factor κB (NF-κB) system describes a family of dimeric transcription factors. Canonical NF-κB signaling is stimulated by and enhances inflammation, whereas noncanonical NF-κB signaling contributes to immune organogenesis. Dysregulation of NF-κB factors drives various inflammatory pathologies, including IBD. Signals from many immune sensors activate NF-κB subunits in the intestine, which maintain an equilibrium between local microbiota and host responses. Genetic association studies of patients with IBD and preclinical mouse models confirm the importance of the NF-κB system in host defense in the gut. Other studies have investigated the roles of these factors in intestinal barrier function and in inflammatory gut pathologies associated with IBD. NF-κB signaling modulates innate and adaptive immune responses and the production of immunoregulatory proteins, anti-inflammatory cytokines, antimicrobial peptides, and other tolerogenic factors in the intestine. Furthermore, genetic studies have revealed critical cell type-specific roles for NF-κB proteins in intestinal immune homeostasis, inflammation, and restitution that contribute to the etiopathology of IBD-associated manifestations. Here, we summarize our knowledge of the roles of these NF-κB pathways, which are activated in different intestinal cell types by specific ligands, and their cross-talk, in fueling aberrant intestinal inflammation. We argue that an in-depth understanding of aberrant immune signaling mechanisms may hold the key to identifying predictive or prognostic biomarkers and developing better therapeutics against inflammatory gut pathologies.

The Antioxidant Properties of Salvia verbenaca Extract Contribute to Its Intestinal Antiinflammatory Effects in Experimental Colitis in Rats

Inflammatory bowel disease (IBD) is a chronic gastrointestinal inflammation with unpredictable symptom fluctuations. While there is no effective cure for IBD, various treatments aim to manage symptoms and improve the quality of life for affected individuals. In recent years, there has been growing interest in the potential benefits of certain natural plants and herbs in the management of IBD. In this regard, this study aimed to evaluate the immunomodulatory and anti-inflammatory effects of a well-characterized extract of Salvia verbenaca (S. verbenaca) in an experimental model of colitis in rats. Interestingly, the daily administration of S. verbenaca (10 and 25 mg/kg) effectively alleviated colitis symptoms, as evidenced by reduced weight/length ratio and colonic damage. Moreover, it reduced oxidative stress markers (MPO and GSH), decreased pro-inflammatory cytokine expression (Il-6, Il-12a, Il-1β, Il-23, Icam-1, Mcp-1, Cinc-1), and preserved the integrity of the intestinal barrier (Villin, Muc-2, Muc-3). These effects suggest S. verbenaca extract could represent a potential complementary candidate to treat gastrointestinal disorders. Its beneficial actions can be related to its antioxidant properties as well as the downregulation of the immune response, which can result in the improvement in the intestine epithelial barrier.

Sex-oriented perspectives in immunopharmacology

Several immunopharmacological agents are effective in the treatment of cancer and immune-mediated conditions, with a favorable impact on life expectancy and clinical outcomes for a large number of patients. Nevertheless, response variation and undesirable effects of these drugs represent major issues, and overall efficacy remains unpredictable. Males and females show a distinct difference in immune system responses, with females generally mounting stronger responses to a variety of stimuli. Therefore, exploring sex differences in the efficacy and safety of immunopharmacological agents would strengthen the practice of precision medicine. As a pharmacological target highlight, programmed cell death 1 ligand 1 (PD-L1) is the first functionally characterized ligand of the coinhibitory programmed death receptor 1 (PD-1). The PD-L1/PD-1 crosstalk plays an important role in the immune response and is relevant in cancer, infectious and autoimmune disease. Sex differences in the response to immune checkpoint inhibitors are well documented, with male patients responding better than female patients. Similarly, higher efficacy of and adherence to tumor necrosis factor inhibitors in chronic inflammatory conditions including rheumatoid arthritis and Crohn's disease have been reported in male patients. The pharmacological basis of sex-specific responses to immune system modulating drugs is actively investigated in other settings such as stroke and type 1 diabetes. Advances in therapeutics targeting the endothelium could soon be wielded against autoimmunity and metabolic disorders. Based on the established sexual dimorphism in immune-related pathophysiology and disease presentation, sex-specific immunopharmacological protocols should be integrated into clinical guidelines.

Effect of aqueous extract of Trigonellafoenum-graecum L. seeds on Acetic acid- induced Ulcerative colitis in rats

Background: Ulcerative colitis (UC) is an inflammatory bowel disorder affecting the colonic mucosa, characterized by intense inflammation and mucosal damage. The present study aimed to evaluate the protective effect of the Trigonellafoenum-graecum L. (TFG) seeds in acetic acid-induced UC in rats. Materials and Methods: Male rats (n=30) were distributed into 5 groups as normal control, UC, standard, and two test groups. Colitis was induced by acetic acid in all the groups except the normal control group. Normal control and UC group received distilled water, the standard group was administered sulfasalazine at 100mg/kg body weight (bw), and test groups, TFG-I, and TFG-II received TFG seed extract at 500 and 1000 mg/kg bw, respectively. The duration of treatment was 7 days, and colitis was induced on day 8. Animals were sacrificed on day 9 and colonic tissue was dissected and collected for biochemical, molecular, and histological analysis. Results: The disease activity index score in standard, TFG-I, and TFG-II (3.33±0.21, 2.66±0.21, and 3.50±0.22) was significantly lesser (P<0.05) than scores in the UC group (4±0.01). The macroscopic score indicating the intensity of mucosal inflammation was significantly decreased (P≤ 0.01) to4.0±0.25, 3.16±0.30, and 3.83±0.40 in standard, TFG-I, and TFG-II groups, respectively compared to the UC group (4.66±0.21). Similarly, there was a significant reduction (P≤0.05) in histological scores of the standard, TFG-I, TFG-II (3.5±0.34, 1.25±0.34, 3.25±0.34) groups compared to the UC group (4.75±0.34). Biochemical assessment in the standard and test groups showed significant increase (P<0.05) in total protein, reduced glutathione (GSH), catalase (CAT), superoxide dismutase (SOD) levels whereas significant reduction (P<0.01) in malondialdehyde (MDA) levels compared to UC group. The pro-inflammatory cytokine TNF-α levels were significantly decreased (P<0.01) in standard, TFG-I, and TFG-II (-1.75±0.007, -0.27±0.17 and -0.51±0.002) when compared to the UC group (0.20±0.02). Conclusion: The study demonstrates the ability of TFG seeds in reducing the inflammatory and oxidative stress induced mucosal damage in acetic acid-induced UC in rats.

Eucommiae cortex polysaccharides attenuate gut microbiota dysbiosis and neuroinflammation in mice exposed to chronic unpredictable mild stress: Beneficial in ameliorating depressive-like behaviors

BACKGROUND

Chronic stress alters gut microbiota composition, as well as induces inflammatory responses and behavioral deficits. Eucommiae cortex polysaccharides (EPs) have been reported to remodel gut microbiota and ameliorate obesogenic diet-induced systemic low-grade inflammation, but their role in stress-induced behavioral and physiological changes is poorly understood.

METHODS

Male Institute of Cancer Research (ICR) mice were exposed to chronic unpredictable stress (CUMS) for 4 weeks and then supplemented with EPs at a dose of 400 mg/kg once per day for 2 weeks. Behavioral test-specific antidepressant and anxiolytic effects of EPs were assessed in FST, TST, EPM, and OFT. Microbiota composition and inflammation were detected using 16S ribosomal RNA (rRNA) gene sequencing, quantitative RT-PCR, western blot, and immunofluorescence.

RESULTS

We found that EPs ameliorated gut dysbiosis caused by CUMS, as evidenced by increasing the abundance of Lactobacillaceae and suppressing the expansion of the Proteobacteria, thereby mitigating intestinal inflammation and barrier derangement. Importantly, EPs reduced the release of bacterial-derived lipopolysaccharides (LPS, endotoxin) and inhibited the microglia-mediated TLR4/NFκB/MAPK signaling pathway, thereby attenuating the pro-inflammatory response in the hippocampus. These contributed to restoring the rhythm of hippocampal neurogenesis and alleviating behavioral abnormalities in CUMS mice. Correlation analysis showed that the perturbed-gut microbiota was strongly correlated with behavioral abnormalities and neuroinflammation.

LIMITATIONS

This study did not clarify the causal relationship between EPs remodeling the gut microbiota and improved behavior in CUMS mice.

CONCLUSIONS

EPs exert ameliorative effects on CUMS-induced neuroinflammation and depression-like symptoms, which may be strongly related to their beneficial effects on gut microbial composition.

Bromodomain-containing protein 4 (BRD4): a key player in inflammatory bowel disease and potential to inspire epigenetic therapeutics

INTRODUCTION

Inflammatory bowel diseases (IBDs) are debilitating chronic inflammatory disorders with increasing prevalence worldwide. Epigenetic regulator bromodomain-containing protein 4 (BRD4) is critical in controlling gene expression of IBD-associated inflammatory cytokine networks. BRD4 as a promising therapeutic target is also tightly associated with many other diseases, such as airway inflammation and fibrosis, cancers, infectious diseases and central nervous system disorders.

AREAS COVERED

This review briefly summarized the critical role of BRD4 in the pathogenesis of IBDs and the current clinical landscape of developing bromodomain and extra terminal domain (BET) inhibitors. The challenges and opportunities as well as future directions of targeting BRD4 inhibition for potential IBD medications were also discussed.

EXPERT OPINION

Targeting BRD4 with potent and specific inhibitors may offer novel effective therapeutics for IBD patients, particularly those who are refractory to anti-TNFα therapy and IBD-related profibrotic. Developing highly specific BRD4 inhibitors for IBD medications may help erase the drawbacks of most current pan-BET/BRD4 inhibitors, such as off-target effects, poor oral bioavailability, and low gut mucosal absorbance. Novel strategies such as combinatorial therapy, BRD4-based dual inhibitors and proteolysis targeting chimeras (PROTACs) may also have great potential to mitigate side effects and overcome drug resistance during IBD treatment.

Tackling Inflammatory Bowel Diseases: Targeting Proinflammatory Cytokines and Lymphocyte Homing

Inflammatory bowel diseases (IBDs) are characterized by chronic inflammatory disorders that are a result of an abnormal immune response mediated by a cytokine storm and immune cell infiltration. Proinflammatory cytokine therapeutic agents, represented by TNF inhibitors, have developed rapidly over recent years and are promising options for treating IBD. Antagonizing interleukins, interferons, and Janus kinases have demonstrated their respective advantages in clinical trials and are candidates for anti-TNF therapeutic failure. Furthermore, the blockade of lymphocyte homing contributes to the excessive immune response in colitis and ameliorates inflammation and tissue damage. Factors such as integrins, selectins, and chemokines jointly coordinate the accumulation of immune cells in inflammatory regions. This review assembles the major targets and agents currently targeting proinflammatory cytokines and lymphatic trafficking to facilitate subsequent drug development.

Pathway Analysis of Genome Wide Association Studies (GWAS) Data Associated with Male Infertility

Background: Infertility is a common condition affecting approximately 10–20% of the reproductive age population. Idiopathic infertility cases are thought to have a genetic basis, but the underlying causes are largely unknown. However, the genetic basis underlying male infertility in humans is only partially understood. The Purpose of the study is to understand the current state of research on the genetics of male infertility and its association with significant biological mechanisms. Results: We performed an Identify Candidate Causal SNPs and Pathway (ICSN Pathway) analysis using a genome-wide association study (GWAS) dataset, and NCBI-PubMed search which included 632 SNPs in GWAS and 451 SNPs from the PubMed server, respectively. The ICSN Pathway analysis produced three hypothetical biological mechanisms associated with male infertility: (1) rs8084 and rs7192→HLA-DRA→inflammatory pathways and cell adhesion; rs7550231 and rs2234167→TNFRSF14→TNF Receptor Superfamily Member 14→T lymphocyte proliferation and activation; rs1105879 and rs2070959→UGT1A6→UDP glucuronosyltransferase family 1 member A6→Metabolism of Xenobiotics, androgen, estrogen, retinol, and carbohydrates. Conclusions: We believe that our results may be helpful to study the genetic mechanisms of male infertility. Pathway-based methods have been applied to male infertility GWAS datasets to investigate the biological mechanisms and reported some novel male infertility risk pathways. This pathway analysis using GWAS dataset suggests that the biological process related to inflammation and metabolism might contribute to male infertility susceptibility. Our analysis suggests that genetic contribution to male infertility operates through multiple genes affecting common inflammatory diseases interacting in functional pathways.

Characterization of Two TNF-Related Subtypes Predicting Infliximab Therapy Responses in Crohn’s Disease

Background

Anti–tumor necrosis factor (TNF) therapy is widely used to treat Crohn’s disease (CD). Unfortunately, 10%–40% of patients have primary non-response to anti-TNF therapy. TNF family genes play crucial roles in inflammation and immune regulation; however, the effects of TNF family genes on CD remain unclear.

Methods

CD expression profiles were downloaded from the Gene Expression Omnibus database. Unsupervised clustering was then used to identify the gene subtypes in CD based on the expressions of TNF family genes. The features of the gene subtypes were characterized using functional enrichment and immune infiltration analyses, and biomarkers of the gene subtypes were identified.

Results

Patients with CD were divided on the basis of unsupervised clustering into two gene subtypes: immune and metabolic. Gene subtype A was significantly correlated with leukocyte migration and cytokine interactions, whereas gene subtype B was associated with metabolic pathways. Whereas 89.5% of the patients in gene subtype B responded to infliximab, only 16.7% of patients in gene subtype A responded. In addition, a combination of interleukin 1 beta (IL1β), interleukin 6 (IL6), and Toll-like receptor 4 (TLR4) can effectively distinguish between gene subtypes A and B.

Conclusion

Comprehensive analyses of the TNF family genes may reveal the underlying pathogenesis of CD. The classification of subtypes may provide new ideas for the personalized treatment of patients with CD.

MEFV and NLRP3 Inflammasome Expression Is Attributed to Immature Macrophages and Correlates with Serum Inflammatory Proteins in Crohn´s Disease Patients

Inflammasomes are intracellular protein complexes whose activation results in proinflammatory cytokines. Inflammasomes are implicated in Crohn´s disease (CD) pathogenesis, yet the contribution of inflammasomes in intestinal epithelial cells (IECs) versus lamina propria (LP) macrophages is poorly understood. Whether inflammasome expression in intestinal tissue reflects the serum inflammatory protein profile of patients is also not known. We aimed to determine the intestinal cell types where inflammasome expression is increased in CD and if they correlate with the serum protein profile. RT-PCR and NanoString nCounter technology were used to characterize inflammasome gene expression in CD patients and controls. The mucosa, LP and IEC cell fractions and FACS-sorted cells were analyzed. Proximity extension assay with a 92-protein panel was used to determine the serum inflammatory protein profile. Compositional analysis was used to correlate ileum inflammasome gene expression with intestinal mononuclear phagocyte populations. We show that NLRP3 and MEFV inflammasome sensors and downstream effector expression including IL-1β are increased in inflamed mucosa of IBD patients and correlate with disease activity. Inflammasome gene expression increased with the abundance of immature intestinal macrophages, and increased IL-1β released by CD LP cells correlated with immature macrophage frequency. Inflammasome gene expression was also increased in circulating monocytes, the precursors of immature intestinal macrophages. Finally, the serum inflammatory profile of CD patients correlates with ileal expression of genes related to NLRP3 and MEFV inflammasomes. Overall, we show that MEFV and NLRP3 inflammasome expression in CD intestine is attributed to the accumulation of immature macrophages and correlates with serum inflammatory proteins.

Response to Anti-α4β7 Blockade in Patients With Ulcerative Colitis Is Associated With Distinct Mucosal Gene Expression Profiles at Baseline

BACKGROUND

Improving treatment outcomes with biological therapy is a demanding current need for patients with inflammatory bowel disease. Discovery of pretreatment prognostic indicators of response may facilitate patient selection and increase long-term remission rates. We aimed to identify baseline mucosal gene expression profiles with predictive value for subsequent response to or failure of treatment with the monoclonal antibody against integrin α4β7, vedolizumab, in patients with active ulcerative colitis (UC).

METHODS

Mucosal expression of 84 immunological and inflammatory genes was quantified in RNA extracted from colonic biopsies before vedolizumab commencement and compared between patients with or without response to treatment. Significantly differentiated genes were further validated in a larger patient cohort and within available public data sets, and their functional profiles were studied accordingly.

RESULTS

In the discovery cohort, we identified 21 genes with a statistically significant differential expression between 54-week responders and nonresponders to vedolizumab. Our validation study allowed us to recognize a "core" mucosal profile that was preserved in both discovery and validation cohorts and in the public database. The applied functional annotation and analysis revealed candidate dysregulated pathways in nonresponders to vedolizumab, including immune cell trafficking, TNF receptor superfamily members mediating noncanonical NF-kB pathway, in addition to interleukin signaling, MyD88 signaling, and toll-like receptors (TLRs) cascade.

CONCLUSIONS

Nonresponse to vedolizumab in UC is associated with specific pretreatment gene-expression mucosal signatures and dysregulation of particular immunological and inflammatory pathways. Baseline mucosal and/or systemic molecular profiling may help in the optimal stratification of patients to receive vedolizumab for active UC.

Gastrointestinal Changes and Alzheimer's Disease

BACKGROUND

There is a well-described mechanism of communication between the brain and gastrointestinal system in which both organs influence the function of the other. This bi-directional communication suggests that disease in either organ may affect function in the other.

OBJECTIVE

To assess whether the evidence supports gastrointestinal system inflammatory or degenerative pathophysiology as a characteristic of Alzheimer's disease (AD).

METHODS

A review of both rodent and human studies implicating gastrointestinal changes in AD was performed.

RESULTS

Numerous studies indicate that AD changes are not unique to the brain but also occur at various levels of the gastrointestinal tract involving both immune and neuronal changes. In addition, it appears that numerous conditions and diseases affecting regions of the tract may communicate to the brain to influence disease.

CONCLUSION

Gastrointestinal changes represent an overlooked aspect of AD, representing a more system influence of this disease.

Targeting Purinergic Receptor P2RX1 Modulates Intestinal Microbiota and Alleviates Inflammation in Colitis

Inflammatory bowel disease (IBD) remains one of the most prevalent gastrointestinal diseases worldwide. Purinergic signaling has emerged as a promising therapeutic target of inflammation-associated diseases. However, little is known about the specific roles of purinergic receptors in IBD. In the present study, expression profile of purinergic receptors was screened in the public Gene Expression Omnibus (GEO) datasets, and we found that expression of P2RX1 was significantly upregulated in inflamed colon tissues. Then, purinergic receptor P2RX1 was genetically ablated in the background of C57BL/6 mice, and dextran sulfate sodium (DSS) was used to induce mice colitis. RNA sequencing results of colon tissues showed that genetic knockout of P2RX1 suppressed the inflammation responses in DSS-induced mice colitis. Flow cytometry indicated that neutrophil infiltration was inhibited in P2RX1 ablated mice. 16S ribosomal DNA sequencing revealed major differences of intestinal microbiota between WT and P2RX1 ablated mice. Functional metagenomics prediction indicated that the indole alkaloid biogenesis pathway was upregulated in P2RX1 gene ablated mice. Further studies revealed that microbiota metabolites (indole alkaloid)-involved aryl hydrocarbon receptor (AhR)/IL-22 axis was associated with the beneficial effects of P2RX1 ablation. Finally, we found that a specific P2RX1 inhibitor succeeded to improve the therapeutic efficiency of anti-TNF-α therapy in DSS-induced mice colitis. Therefore, our study suggests that targeting purinergic receptor P2RX1 may provide novel therapeutic strategy for IBD.

Tilapia head glycolipids protect mice against dextran sulfate sodium-induced colitis by ameliorating the gut barrier and suppressing NF-kappa B signaling pathway

The purpose of this study was to evaluate the relieving effect of tilapia head glycolipids (TH-GLs) on dextran sulfate sodium (DSS)-induced colitis in mice and to further explore its mechanism. Mice were orally administered 3% (w/v) DSS to establish a model of ulcerative colitis (UC), and subsequently treated with TH-GLs or sulfasalazine. In addition, the expression of key targets in the intestinal mucosal barrier and the inflammatory signal pathway were studied by combining immunochemical analysis techniques. The results showed that varying doses of TH-GLs can significantly improve colon lesions caused by DSS, reduce histological scores, increase mucus secretion, extend colon length, increase weight, and inhibit the occurrence of inflammatory cytokines such as tumor necrosis factor-α (TNF-α), interferon-γ (IFN-γ), Interleukin-1β (IL-1β), and Interleukin- 6 (IL-6). Further, studies have shown that TH-GLs increase the secretion of MUC2 and up-regulate the expression of tight junction related proteins, such as ZO-1 and Occludin. In addition, TH-GLs significantly down-regulated the protein expression levels of TNF-α, IKK-β, and nuclear factor-κB (NF-κB). Here, we have elucidated the potential mechanism of TH-GLs in protecting mice with colitis. In general, this study shows that TH-GLs could improve the symptoms of UC by improving the gut barrier and inhibiting inflammatory signals, which provides a scientific basis for future clinical applications.

Soluble ligands as drug targets for treatment of inflammatory bowel disease

Inflammatory bowel disease (IBD), which includes Crohn's disease and ulcerative colitis, is characterized by persistent inflammation in a hereditarily susceptible host. In addition to gastrointestinal symptoms, patients with IBD frequently suffer from extra-intestinal complications such as fibrosis, stenosis or cancer. Mounting evidence supports the targeting of cytokines for effective treatment of IBD. Cytokines can be included in a newly proposed classification "soluble ligands" that has become the third major target of human protein therapeutic drugs after enzymes and receptors. Soluble ligands have potential significance for research and development of anti-IBD drugs. Compared with traditional drug targets for IBD treatment, such as receptors, at least three factors contribute to the increasing importance of soluble ligands as drug targets. Firstly, cytokines are the main soluble ligands and targeting of them has demonstrated efficacy in patients with IBD. Secondly, soluble ligands are more accessible than receptors, which are embedded in the cell membrane and have complex tertiary membrane structures. Lastly, certain potential target proteins that are present in membrane-bound forms can become soluble following cleavage, providing further opportunities for intervention in the treatment of IBD. In this review, 49 drugs targeting 25 distinct ligands have been evaluated, including consideration of the characteristics of the ligands and drugs in respect of IBD treatment. In addition to approved drugs targeting soluble ligands, we have also assessed drugs that are in preclinical research and drugs inhibiting ligand-receptor binding. Some new types of targetable soluble ligands/proteins, such as epoxide hydrolase and p-selectin glycoprotein ligand-1, are also introduced. Targeting soluble ligands not only opens a new field of anti-IBD drug development, but the circulating soluble ligands also provide diagnostic insights for early prediction of treatment response. In conclusion, soluble ligands serve as the third-largest protein target class in medicine, with much potential for the drugs targeting them.

A profile of multiple circulating tumor necrosis factor receptors associated with early progressive kidney decline in Type 1 Diabetes is similar to profiles in autoimmune disorders

This study comprehensively evaluated the association between known circulating tumor necrosis factor (TNF) superfamily ligands and receptors and the development of early progressive kidney decline (PKD) leading to end-stage kidney disease (ESKD) in Type 1 diabetes. Participants for the study were from the Macro-Albuminuria Study (198 individuals), and the Micro-Albuminuria Study (148 individuals) of the Joslin Kidney Study. All individuals initially had normal kidney function and were followed for seven-fifteen years to determine the slope of the estimate glomerular filtration rate and to ascertain onset of ESKD. Plasma concentrations of 25 TNF superfamily proteins were measured using proximity extension assay applied in the OLINK proteomics platform. In the both studies risk of early PKD, determined as estimated glomerular filtration rate loss greater than or equal to three ml/min/1.73m2/year, was associated with elevated circulating levels of 13 of 19 TNF receptors examined. In the Macro-Albuminuria Study, we obtained similar findings for risk of progression to ESKD. These receptors comprised: TNF-R1A, -R1B, -R3, -R4, -R6, -R6B, -R7, -R10A, -R10B, -R11A, -R14, -R21, and -R27. Serial measurements showed that circulating levels of these TNF receptors had increased before the onset of PKD. In contrast, none of the six measured TNF ligands showed association with risk of early PKD. Of significance, the disease process that underlies PKD leading to ESKD in Type 1 diabetes has a profile also seen in autoimmune disorders. The mechanisms of this enrichment may be causally related to the development of PKD in Type 1 diabetes and must be investigated further. Thus, some of these receptors may be used as new risk predictors of ESKD.

Standardized Fraction of Turbinaria ornata Alleviates Dextran Sulfate Sodium-Induced Chronic Colitis in C57BL/6 Mice via Upregulation of FOXP3+ Regulatory T Cells

Turbinaria ornata is a tropical brown algae (seaweed) known to have anti-inflammatory properties. In this study, we analyzed T. ornata extract (TOE) using liquid chromatography quadrupole time of flight mass spectrometry (LC-QTOF-MS) and nuclear magnetic resonance (NMR) and evaluated the in vivo efficacy of TOE against dextran sulfate sodium-induced chronic colitis in C57BL/6 mice. The bioactive fraction of TOE was administered orally daily for 6 weeks to mice under different treatments normal, colitis, and colitis + conventional drug (5-aminosalicylic acid, 5-ASA). Regarding clinical manifestation, the disease activity index and colon length of the colitis + TOE group were significantly reduced compared to those of the colitis group. The results of myeloperoxidase activity and histopathological examination showed similar results. Western blot analysis of colon tissues revealed that cyclooxygenase-2, tumor necrosis factor alpha (TNF-α), and phosphorylated signal transducer and activator of transcription-3 (p-STAT3) were significantly decreased in the colitis + 5-ASA group, whereas forkhead box P3 (FOXP3) was increased. qPCR results showed changes in T cell subsets; the administration of TOE upregulated regulatory T cell (Treg) expression, although T helper 17 cell (Th17) expression did not change significantly. Interestingly, the colitis + TOE group showed high levels of both Th1 and Th2 transcription factors, but the secreted cytokine interferon (IFN)-γ and interleukin (IL)-4 remained unchanged and somewhat reduced. Additionally, TNF-α gene expression was significantly reduced in the colitis + TOE group. IL-6 mRNA levels were also decreased, although not significantly. Four compounds were structurally elucidated using 1D- and 2D-NMR spectroscopy, and five compounds were fully identified or tentatively characterized using LC-QTOF-MS. In conclusion, TOE could alleviate chronic colitis via upregulation of Foxp3+ Treg cells and production of the anti-inflammatory cytokine IL-10, which directly inhibits macrophages and pro-inflammatory cytokine synthesis, leading to reduced colitis.

Is Polymorphism in the Apoptosis and Inflammatory Pathway Genes Associated With a Primary Response to Anti-TNF Therapy in Crohn's Disease Patients?

Anti-tumor necrosis factor (TNF) therapy is used for the induction and maintenance of remission in Crohn’s disease (CD) patients. However, primary nonresponders to initial treatment constitute 20%–40% of cases. The causes of this phenomenon are still unknown. In this study, we aimed to determine the genetic predictors of the variable reactions of CD patients to anti-TNF therapy. Using long-range PCR libraries and the next-generation sequencing (NGS) method, we performed broad pharmacogenetic studies including a panel of 23 genes (TNFRSF1A, TNFRSF1B, CASP9, FCGR3A, LTA, TNF, FAS, ADAM17, IL17A, IL6, MMP1, MMP3, S100A8, S100A9, S100A12, TLR2, TLR4, TLR9, CD14, IL23R, IL23, IL1R, and IL1B) in a group of 107 diagnosed and clinically characterized CD patients following anti-TNF therapy. In the studied group, we indicated, in total, 598 single nucleotide variants for all analyzed genomic targets. Twelve patients (11.2%) did not respond to the induction therapy, which was associated with alleles in 11 loci located in FCGR3A (rs7539036, rs6672453, rs373184583, and rs12128686), IL1R (rs2041747), TNFRSF1B (rs5746053), IL1B (rs1071676, rs1143639, rs1143637, and rs1143634), and FAS (rs7896789) genes. After multiple comparison corrections, the results were not statistically significant, however for nonresponders the alleles distribution for those loci presented large differences and specified scheme compared to responders and populations. These findings require further investigation in an independent larger cohort before introducing them for a clinical setting, however, we identified an interesting direction. Polymorphism of the FCGR3A, IL1R, TNFRSF1B, IL1B, and FAS genes could be a predictor of the primary response to anti-TNF therapy in CD patients.

The role of FAS gene variants in inflammatory bowel disease

BACKGROUND/AIMS

The analysis of genes thought to be important in inflammatory bowel disease (IBD) has shown that more than half of IBD-related genes are also associated with other autoimmune diseases. The aim of this study was to detect a possible association between the polymorphisms of the (-670 A/G, -1377 G/A) fFas cell surface death receptor (FAS) gene promoter and susceptibility to IBD in the Turkish population.

MATERIALS AND METHODS

In total, 125 patients with IBD, including 73 ulcerative colitis and 52 Crohn's disease and also 101 healthy controls without any pathological signs of IBD were considered for the study. Real-time polymerase chain reaction technique was used to detect FAS polymorphisms in this study.

RESULTS

The analysis of FAS -670 A/G polymorphism indicated that the frequency of GG genotype was significantly increased in patients compared with controls (p<0.001). Additionally, AG genotype (p<0.001) and A allele (p<0.001) frequencies were higher in controls than in patients. The analysis of FAS -1377 G/A polymorphism revealed that the frequency of AA genotype was meaningfully increased in patients compared with controls (p<0.001). Additionally, GG genotype (p<0.001) and G allele (p<0.001) frequencies were increased in controls when compared with patients.

CONCLUSION

FAS -670A/G GG genotype seemed to be a protective allele against IBD; however, AA genotype and A allele were associated with elevated risk of IBD. In the FAS -1377G/A polymorphism, frequencies of the G allele and GG genotype were observed to be protective against IBD, whereas AA, GA genotypes, and A allele frequency increased in the patient group.

Consumption of a baked corn and bean snack reduced chronic colitis inflammation in CD-1 mice via downregulation of IL-1 receptor, TLR, and TNF-α associated pathways

Ulcerative colitis (UC) is a condition that has been rising in the number of cases around the world. Food products made from natural ingredients such as corn and common bean might serve as alternatives for the treatment of UC. This study aimed to assess the anti-inflammatory effect of the consumption of a baked corn and bean snack (CBS) in an in vivo model of UC using 2% dextran sodium sulfate (DSS) as inductor of colitis. CD-1 mice (45, n = 9/group) were randomly separated into 5 groups, treated for 6-weeks as follows: G1 (basal diet, BD), G2 (2% DSS), G3 (20 g CBS/body weight BW/day + BD), G4 (40 g CBS/BW/day + BD) and G5 (60 g CBS/BW/day + BD). BW, Disease Activity Index (DAI), and feces were collected throughout the treatment. After euthanasia, organs (spleen, liver, and colon) were excised and weighed. Feces were analyzed for β-glucuronidase (β-GLUC) activity and gas-chromatography. The colons were analyzed for histopathology, myeloperoxidase (MPO) activity, and gene analysis. At the end of treatments, among the DSS-induced groups, G3 exhibited the lowest BW losses (11.5%), MPO activity (10.4%) and β-GLUC (8.6%). G4 presented the lowest DAI (0.88), relative spleen weight, and histological inflammation score (p < 0.05). Compared to G2, CBS consumption significantly (p < 0.05) reduced serum TNF-α, IL-10, and MCP-1 levels. The fecal metabolome analysis ranked 9-decenoic acid, decane, and butyric acid as the main contributors of pathways associated with the β-oxidation of fatty acids. G4 showed the highest fecal/cecal contents of short-chain fatty acids among all the DSS-induced groups. For the gene expression, G4 was clustered with G1, showing a differential inhibition of the pro-inflammatory genes Il1r1, Il1a, Tlr4, Tlr2, and Tnfrsf1b. In conclusion, CBS consumption decreased the inflammatory state and reduced the expression of the IL-1 receptor, TLR, and TNF-α-associated pathways in DSS-induced UC in CD-1 mice.

Diagnostic methods for the measurement of human TNF-alpha in clinical laboratory

Measurement of Tumour Necrosis Factor alpha (TNF-α) in peripheral blood is a useful tool to assess inflammatory responses in a large range of diseases. One of the major challenges for cytokine analysis is the availability of a proper analytical tool with high specificity, accuracy, linearity, precision, stability, and analytical sensitivity. Although available immunoassays are usually robust and reproducible, it is also true that they are not interchangeable. Two ELISA, four flow cytometric bead array (CBA) and four Luminex immunoassays were compared. Correlation between different techniques was almost absent, while some immunoassays based on the same technique showed significant correlation. Among the ten different assays evaluated, just few of them complied with the pre-established acceptance validation criteria. Interestingly, sera and plasma collected from the same healthy donor had significant different reference values. Samples stability was maintained in serum up to one week at four degrees, while plasma was stable only when it was frozen. Since several anti-inflammatory treatments are based on biologics targeting TNF-α (anti-TNF-α antibodies), potential interference with the immunoassays was tested and resulted relevant. This study shows that although each immunoassay presents benefits and drawbacks, just few assays are suitable for the measurement of TNF-α in clinical laboratories, demonstrating that, so far, the measurement of TNF-α in human blood is still not yet harmonised. In addition, we found that false negative results caused by anti-TNF-α treatments should be carefully considered for results interpretation.

Systemic Molecular Mediators of Inflammation Differentiate Between Crohn's Disease and Ulcerative Colitis, Implicating Threshold Levels of IL-10 and Relative Ratios of Pro-inflammatory Cytokines in Therapy

BACKGROUND AND AIMS

Faecal diversion is associated with improvements in Crohn's disease but not ulcerative colitis, indicating that differing mechanisms mediate the diseases. This study aimed to investigate levels of systemic mediators of inflammation, including fibrocytes and cytokines, [1] in patients with Crohn's disease and ulcerative colitis preoperatively compared with healthy controls and [2] in patients with Crohn's disease and ulcerative colitis prior to and following faecal diversion.

METHODS

Blood samples were obtained from healthy individuals and patients with Crohn's disease or ulcerative colitis. Levels of circulating fibrocytes were quantified using flow cytometric analysis and their potential relationship to risk factors of inflammatory bowel disease were determined. Levels of circulating cytokines involved in inflammation and fibrocyte recruitment and differentiation were investigated.

RESULTS

Circulating fibrocytes were elevated in Crohn's disease and ulcerative colitis patients when compared with healthy controls. Smoking, or a history of smoking, was associated with increases in circulating fibrocytes in Crohn's disease, but not ulcerative colitis. Cytokines involved in fibrocyte recruitment were increased in Crohn's disease patients, whereas patients with ulcerative colitis displayed increased levels of pro-inflammatory cytokines. Faecal diversion in Crohn's disease patients resulted in decreased circulating fibrocytes, pro-inflammatory cytokines, and TGF-β1, and increased IL-10, whereas the inverse was observed in ulcerative colitis patients.

CONCLUSIONS

The clinical effect of faecal diversion in Crohn's disease and ulcerative colitis may be explained by differing circulating fibrocyte and cytokine responses. Such differences aid in understanding the disease mechanisms and suggest a new therapeutic strategy for inflammatory bowel disease.

Identification of Epigenetic Methylation Signatures With Clinical Value in Crohn's Disease

INTRODUCTION

DNA methylation is an epigenetic mechanism that regulates gene expression and represents an important link between genotype, environment, and disease. It is a reversible and inheritable mechanism that could offer treatment targets. We aimed to assess the methylation changes on specific genes previously associated with Crohn's disease (CD) and to study their possible associations with the pathology.

METHODS

We included 103 participants and grouped them into 2 cohorts (a first [n = 31] and a second validation [n = 72] cohort), with active CD (aCD) and inactive CD (iCD) and healthy participants (CTR). DNA was obtained from the peripheral blood and analyzed by the Agena platform. The selected genes were catalase (CAT), α-defensin 5 (DEFA5), FasR, FasL, tumor necrosis factor (TNF), TNFRSF1A, TNFRSF1B, PPA2, ABCB1, NOD2, PPARγ, and PKCζ. We used the elastic net algorithm and R software.

RESULTS

We studied 240 CpGs. Sixteen CpGs showed differential methylation profiles among aCD, iCD, and CTR. We selected for validation those with the greatest differences: DEFA5 CpG_11; CpG_13; CAT CpG_31.32; TNF CpG_4, CpG_12; and ABCB1 CpG_21. Our results validated the genes DEFA5 (methylation gain) and TNF (methylation loss) with P values < 0.001. In both cases, the methylation level was maintained and did not change with CD activity (aCD vs iCD). The subanalysis comparison between aCD and iCD showed significant differential methylation profiles in other CpGs: TNF, FAS, ABCB1, CAT, and TNFRS1BF genes.

DISCUSSION

The methylation status of DEFA5 and TNF genes provides a signature biomarker that characterizes patients with CD and supports the possible implication of the environment and the immune system in CD pathogenesis.

Lactobacillus plantarum CAU1055 ameliorates inflammation in lipopolysaccharide-induced RAW264.7 cells and a dextran sulfate sodium-induced colitis animal model

This study aimed to screen lactic acid bacteria (LAB) for their anti-inflammatory activity by using RAW264.7 cells and dextran sulfate sodium (DSS)-induced colitis. In all, 192 LAB strains were isolated from healthy human feces, of which 8 strains showed excellent nitric oxide (NO) inhibitory activity. Peptidoglycan extracts of these 8 LAB strains were subjected to NO assay, Western blot, and ELISA. Among the 8 tested strains, extracts of 4 strains significantly inhibited the production of NO, related enzyme activities such as inducible nitric oxide synthase and cyclooxygenase 2, and key cytokines such as tumor necrosis factor-α and IL-6 in RAW264.7 cells. The 4 strains belonged to Lactobacillus (CAU1054, CAU1055, CAU1064, and CAU1301). Oral administration of the 4 strains inhibited DSS-induced body weight loss, colon shortening, and colon damage in ICR mice. The colon tissue of the mice treated with Lactobacillus plantarum strain CAU1055 had significantly reduced levels of inducible nitric oxide synthase, cyclooxygenase 2, tumor necrosis factor-α, and IL-6. We found that strain CAU1055 could be used as a candidate probiotic strain for the prevention and treatment of inflammatory bowel disease. Further studies are warranted to confirm the mechanisms of interaction between peptidoglycan of L. plantarum strain CAU1055 and upstream cellular signaling mediators.

Genetic Studies of Inflammatory Bowel Disease-Focusing on Asian Patients

The pathogenesis of inflammatory bowel disease (IBD) is not well-understood; however, increased and persistent intestinal inflammation, due to inappropriate immune responses that are caused by interactions between genetic factors, gut microbiota, and environmental factors, are thought to lead to IBD. Various studies have identified more than 240 genetic variants related to IBD. These genetic variants are involved in innate and adaptive immunity, autophagy, defective bacterial handing, interleukin-23 and 10 signaling, and so on. According to several epidemiological and clinical studies, the phenotypes and clinical course of IBD differ between Asians and Europeans. Although the risk loci for IBD typically overlap between Asians and Westerners, genetic heterogeneity has been detected in many loci/genes, such as NOD2/CARD15, TNFSF15 and human leukocyte antigen, contributing to the risk of IBD. Thus, although common pathways exist between Westerners and Asians in the development of IBD, their significance may differ for individual pathways. Although genetic studies are not universally applicable in the clinical field, they may be useful for diagnosing and categorizing IBD, predicting therapeutic responses and toxicity to drugs, and assessing prognosis by risk modeling, thereby enabling precision medicine for individual patients.

Overlapping irritable bowel syndrome and inflammatory bowel disease

The pathogenesis of irritable bowel-type symptoms occurring in patients with inflammatory bowel disease who are in apparent remission continues to generate scientific controversy and the interpretation and management of these symptoms, so distressing to the sufferer, represent major challenges for the clinician. On the one hand, these symptoms often satisfy Rome IV criteria for IBS and their occurrence correlates highly with anxiety, a known trigger for IBS. On the other hand, recent studies have shown that many of these patients exhibit subtle inflammatory changes. These observations beg the question: are these symptoms "true" IBS superimposed on IBD, or an active but subclinical form of IBD? While it is certain that earlier studies failed to detect subclinical inflammation, it is also evident that even with the use of sensitive biomarkers for inflammation, such as calprotectin and lactoferrin backed up by pan-endoscopy and biopsy to exclude ongoing inflammatory activity in its most subtle form, the prevalence of IBS-type symptoms remains higher than expected in the IBD patient. Pending further definition of its etiology and pathology, we coined the term irritable inflammatory bowel syndrome (IIBS) to refer to this phenomenon. Here we explore the risk factors for this entity, sift through clues to its pathogenesis and attempt to provide, albeit bereft of a robust evidence base, an approach to its management.

Sex Differences in Response to TNF-Inhibiting Drugs in Patients With Spondyloarthropathies or Inflammatory Bowel Diseases

Spondyloarthritis (SpA) and inflammatory bowel diseases (IBD) are chronic inflammatory diseases characterized by an aberrant immune response and inflammation with a key role for TNF in their pathogenesis. Accordingly, TNF-inhibiting therapy (TNFi) has dramatically improved the management of these diseases. However, about 30% of patients discontinue TNFi for lack of response, loss of response, and side effects and/or adverse events. Thus, the possibility to identify in advance those patients who will have a good response to TNFi would be extremely beneficial. The aim of this study was to investigate differences between males and females with either SpA or IBD in response to TNFi molecules, i.e., infliximab (IFX) and adalimumab (ADA), considering the reasons for TNFi withdraw. Data of 594 patients, 349 with IBD (M/F: 194/155) and 245 with SpA (M/F: 123/122), previously unexposed to TNFi, were collected. In the IBD group, the rate of female patients discontinuing ADA was significantly higher than that of male patients (p = 0.03). No difference emerged according to the distribution of reason for discontinuation. Otherwise, a similar discontinuation rate between female and male patients receiving IFX therapy was observed. In the SpA group, the overall discontinuation rate was not different between males and females both for ADA and IFX. However, in patients treated with ADA, males interrupted therapy more frequently than females due to lack of response (p = 0.03). In conclusion, the assessment of sex differences in TNFi response could help physicians personalize the therapeutic approach in a sex-oriented perspective.

The TNF Family of Ligands and Receptors: Communication Modules in the Immune System and Beyond

The tumor necrosis factor (TNF) and TNF receptor (TNFR) superfamilies (TNFSF/TNFRSF) include 19 ligands and 29 receptors that play important roles in the modulation of cellular functions. The communication pathways mediated by TNFSF/TNFRSF are essential for numerous developmental, homeostatic, and stimulus-responsive processes in vivo. TNFSF/TNFRSF members regulate cellular differentiation, survival, and programmed death, but their most critical functions pertain to the immune system. Both innate and adaptive immune cells are controlled by TNFSF/TNFRSF members in a manner that is crucial for the coordination of various mechanisms driving either co-stimulation or co-inhibition of the immune response. Dysregulation of these same signaling pathways has been implicated in inflammatory and autoimmune diseases, highlighting the importance of their tight regulation. Investigation of the control of TNFSF/TNFRSF activities has led to the development of therapeutics with the potential to reduce chronic inflammation or promote anti-tumor immunity. The study of TNFSF/TNFRSF proteins has exploded over the last 30 yr, but there remains a need to better understand the fundamental mechanisms underlying the molecular pathways they mediate to design more effective anti-inflammatory and anti-cancer therapies.

Distinct Expression Patterns of Two Tumor Necrosis Factor Superfamily Member 15 Gene Isoforms in Human Colon Cancer

BACKGROUND

Tumor necrosis factor superfamily member 15 (TNFSF15) gene is involved in development of several cancers. It encodes two proteins: tumor necrosis factor ligand-related molecule 1A (TL1A) and vascular endothelial growth inhibitor 192 (VEGI-192). The main receptor for TL1A is death receptor 3 (DR3).

AIMS

We investigated expression of TL1A, VEGI-192, and DR3 transcripts in different stages of colon cancer and compared them with survival of patients. We also aimed to reveal possible effects of microsatellite instability (MSI) and selected TNFSF15 single-nucleotide polymorphisms (SNPs) on expression of this gene.

METHODS

Forty-five healthy individuals and 95 colon cancer patients were included in the study. Expression of VEGI-192, TL1A, and DR3 was measured by quantitative PCR. SNP and MSI analyses were performed on DNA isolated from normal or cancer tissue.

RESULTS

Expression of VEGI-192 and TL1A was elevated in colon cancer, although the level of VEGI-192 decreased, while the level of TL1A increased with the progression of cancer. Patients with low expression of TL1A and/or high expression of VEGI-192 in tumor-transformed tissue showed longer survival. DR3 expression was decreased in the cancer, but it did not change with the tumor progression. Alleles T of rs6478108 and G of rs6478109 SNPs were associated with elevated expression of the TNFSF15 gene. There was no relation between the MSI status and TNFSF15 expression levels.

CONCLUSIONS

Expression of the TNFSF15 gene isoforms was associated with the progression of colon cancer. Levels of TL1A and VEGI-192 transcripts can be considered as independent prognostic factors for colon cancer.

Critical Role of Tumor Necrosis Factor Signaling in Mesenchymal Stem Cell-Based Therapy for Autoimmune and Inflammatory Diseases

Mesenchymal stem cells (MSCs) have been broadly used as a therapy for autoimmune disease in both animal models and clinical trials. MSCs inhibit T effector cells and many other immune cells, while activating regulatory T cells, thus reducing the production of pro-inflammatory cytokines, including tumor necrosis factor (TNF), and repressing inflammation. TNF can modify the MSC effects via two TNF receptors, i.e., TNFR1 in general mediates pro-inflammatory effects and TNFR2 mediates anti-inflammatory effects. In the central nervous system, TNF signaling plays a dual role, which enhances inflammation via TNFR1 on immune cells while providing cytoprotection via TNFR2 on neural cells. In addition, the soluble form of TNFR1 and membrane-bound TNF also participate in the regulation to fine-tune the functions of target cells. Other factors that impact TNF signaling and MSC functions include the gender of the host, disease course, cytokine concentrations, and the length of treatment time. This review will introduce the fascinating progress in this aspect of research and discuss remaining questions and future perspectives.

TNF-α exerts potent anti-rotavirus effects via the activation of classical NF-κB pathway

Active virus-host interactions determine the outcome of pathogen invasions. It has been shown that in isolated dendritic cells (DCs), rotavirus can induce the expression of tumor necrosis factor α (TNF-α), a vital cytokine mediating host immune responses. However, the role of TNF-α in rotavirus infection is unknown. In this study, we demonstrated that TNF-α has potent anti-rotavirus effects, independent of type I interferon production. Blocking of TNF-α by infliximab, a clinically available TNFα antibody, totally abrogated this effect. Mechanistic studies revealed that the anti-rotavirus effect of TNF-α was achieved by NFκB-regulated genes via the activation of classical nuclear factor κB (NF-κB) signaling. Our study reveals the pivotal role and the mechanism-of-actions of TNF-α in the host defense against rotavirus. Thus, this knowledge may contribute to the better understanding of the complexity of rotavirus-host interactions.

Smad nuclear interacting protein 1 (SNIP1) inhibits intestinal inflammation through regulation of epithelial barrier function

Smad nuclear interacting protein 1 (SNIP1) has been implicated in the pathogenesis of inflammatory bowel disease (IBD). However, the mechanisms involved are still largely unknown. Our results demonstrated that SNIP1 was markedly decreased in intestinal epithelial cells (IEC) from IBD patients compared with healthy controls. Impaired expression of SNIP1 caused a significant decrease of transepithelial electrical resistance but an increase of fluorescein isothiocyanate-dextran flux in Caco-2 monolayers, whereas overexpression of SNIP1 reversed such effects. Overexpression of SNIP1 also inhibited the activity of NF-κB p65 and proinflammatory cytokine production (e.g., TNF-α, IL-1β, and IL-8) by IEC. Importantly, supplementation of exogenous SNIP1 significantly ameliorated intestinal mucosal inflammation in experimental colitis, characterized by less-severe intestinal epithelial barrier damage and decreased proinflammatory cytokine production. Our data thus demonstrated a novel mechanism whereby SNIP1 regulates intestinal inflammation through modulating intestinal epithelial barrier function. Targeting SNIP1 may provide a therapeutic approach for the treatment of IBD.

Biologic-Induced Infections in Inflammatory Bowel Disease: The TNF-α Antagonists

Objective: To review the mechanism and association of infectious risk among the tumor-necrosis factor α (TNF-α) antagonists used in inflammatory bowel disease. Data Sources: A PubMed literature search was performed using the following search terms: infliximab, adalimumab, certolizumab, golimumab, inflammatory bowel disease, crohn’s, ulcerative colitis, adverse effects, adverse events, safety, and infection. Study Selection and Data Extraction: Meta-analyses and cohort studies with outcomes pertaining to quantitative infectious risk were reviewed. Case reports and case series describing association between TNF-α inhibitors and infection were also reviewed. Data Synthesis: A total of 7 recent meta-analyses of randomized trials demonstrate inconclusive association of infection with TNF-α antagonists. Registry data suggest that medications carry an independent risk of opportunistic infections. Risk factors for infection include older age, malnutrition, diabetes, and possibly combination therapy. Reported infections vary widely but include intracellular and granulomatous bacteria, viruses, and fungi. Conclusion: TNF-α antagonists are associated with an increased risk of opportunistic infection, although this risk has not been demonstrated conclusively in randomized controlled trials. Knowledge of concomitant risk factors, mechanism of infectious risk, and available treatment options can improve patient care in the clinical setting.

Procalcitonin in inflammatory bowel disease: Drawbacks and opportunities

The measurement of procalcitonin has recently become a mainstay for the diagnosis and therapeutic management of severe bacterial infections, especially those sustained by Gram-negative bacteria. Therefore, the aim of this article is to provide a narrative overview on the potential role of procalcitonin measurement in patients with inflammatory bowel disease (IBD). According to the available scientific literature, the clinical significance of procalcitonin for diagnosing IBD or monitoring disease activity remains elusive, and its association with disease severity is confined to a limited number of case-control studies, with low sample size. Nevertheless, literature data also suggests that a supranormal procalcitonin serum concentration (i.e., > 0.5 ng/mL) may reflect the presence of a number of infective complications in IBD, especially bacterial enterocolitis, bacterial gastroenteritis, intraabdominal abscess, postsurgical infection and sepsis. Rather than for diagnosing or assessing disease activity, the measurement of this biomarker may hence retain practical clinical significance for early prediction, timely diagnosis and therapeutic monitoring of many IBD-associated infections and complications.

Comparative Network Analysis of Patients with Non-Small Cell Lung Cancer and Smokers for Representing Potential Therapeutic Targets

Cigarette smoking is the leading cause of lung cancer worldwide. In this study, we evaluated the serum autoantibody (AAb) repertoires of non-small cell lung cancer (NSCLC) patients and smokers (SM), leading to the identification of overactivated pathways and hubs involved in the pathogenesis of NSCLC. Surface- and solution-phase biopanning were performed on immunoglobulin G purified from the sera of NSCLC and SM groups. In total, 20 NSCLC- and 12 SM-specific peptides were detected, which were used to generate NSCLC and SM protein datasets. NSCLC- and SM-related proteins were visualized using STRING and Gephi, and their modules were analyzed using Enrichr. By integrating the overrepresented pathways such as pathways in cancer, epithelial growth factor receptor, c-Met, interleukin-4 (IL-4) and IL-6 signaling pathways, along with a set of proteins (e.g. phospholipase D (PLD), IL-4 receptor, IL-17 receptor, laminins, collagens, and mucins) into the PLD pathway and inflammatory cytokines network as the most critical events in both groups, two super networks were made to elucidate new aspects of NSCLC pathogenesis and to determine the influence of cigarette smoking on tumour formation. Taken together, assessment of the AAb repertoires using a systems biology approach can delineate the hidden events involved in various disorders.

Colitis Is Effectively Ameliorated by (±)-8-Acetonyl-dihydrocoptisine via the XBP1-NF-κB Pathway

Ulcerative colitis (UC) is a recurrent, chronic intestinal disease. Available treatments for UC are poor effective and/or cause severe adverse events. X-box binding protein 1 (XBP1) and nuclear factor-κB (NF-κB) have been reported to play important roles in UC. Specifically, deletion or downregulation of XBP1 leads to spontaneous enteritis and results in imbalanced secretion of NF-κB and other proinflammatory cytokines. (±)-8-acetonyl-dihydrocoptisine, i.e., (±)-8-ADC, is a monomer semi-synthesized from coptisine. In vitro, (±)-8-ADC activated the transcriptional activity of XBP1, inhibited expression of NF-κB, and reduced production of proinflammatory cytokines, such as tumor necrosis factor alpha (TNF-α) and interleukin-1 beta (IL-1β), in lipopolysaccharide-stimulated IEC6 cells. Therefore, silencing XBP1 would reduce the inhibition effect of (±)-8-ADC on NF-κB expression and the cytokines secretion in vitro. In a dextran sulfate sodium-induced colitis mouse model, oral administration of (±)-8-ADC ameliorated weight loss and colon contracture, and decreased the average disease activity index score and pathological damage. Simultaneously, (±)-8-ADC also increased XBP1 expression, and decreased NF-κB expression and secretion of myeloperoxidase, TNF-α, IL-6 and IL-1β in the colon. Therefore, (±)-8-ADC may ameliorate UC via the XBP1-NF-κB pathway and should be considered as a therapeutic candidate for UC.

Genetic polymorphisms predict response to anti-tumor necrosis factor treatment in Crohn’s disease

AIM

To investigate genetic factors that might help define which Crohn’s disease (CD) patients are likely to benefit from anti-tumor necrosis factor (TNF) therapy.

METHODS

This was a prospective cohort study. Patients were recruited from a university digestive disease practice database. We included CD patients who received anti-TNF therapy, had available medical records (with information on treatment duration and efficacy) and who consented to participation. Patients with allergic reactions were excluded. Patients were grouped as ever-responders or non-responders. Genomic DNA was extracted from peripheral blood, and 7 single nucleotide polymorphisms (SNPs) were assessed. The main outcome measure (following exposure to the drug) was response to therapy. The patient genotypes were assessed as the predictors of outcome. Possible confounders and effect modifiers included age, gender, race, and socioeconomic status disease, as well as disease characteristics (such as Montreal criteria).

RESULTS

121 patients were included. Twenty-one were non-responders, and 100 were ever-responders. Fas ligand SNP (rs763110) genotype frequencies, TNF gene -308 SNP (rs1800629) genotype frequencies, and their combination, were significantly different between groups on multivariable analysis controlling for Montreal disease behavior and perianal disease. The odds of a patient with a Fas ligand CC genotype being a non-responder were four-fold higher as compared to a TC or TT genotype (P = 0.009, OR = 4.30, 95%CI: 1.45-12.80). The presence of the A (minor) TNF gene -308 allele correlated with three-fold higher odds of being a non-responder (P = 0.049, OR = 2.88, 95%CI: 1.01-8.22). Patients with the combination of the Fas ligand CC genotype and the TNF -308 A allele had nearly five-fold higher odds of being a non-responder (P = 0.015, OR = 4.76, 95%CI: 1.35-16.77). No difference was seen for the remaining SNPs.

CONCLUSION

The Fas-ligand SNP and TNF gene -308 SNP are associated with anti-TNF treatment response in CD and may help select patients likely to benefit from therapy.

Altered Cytokine Expression and Barrier Properties after In Vitro Infection of Porcine Epithelial Cells with Enterotoxigenic Escherichia coli and Probiotic Enterococcus faecium

The aim of the present study was to elucidate the effects of the probiotic feed additive Enterococcus faecium NCIMB 10415 (E. faecium) on porcine jejunal epithelial cells (IPEC-J2) during an in vitro challenge with enterotoxigenic Escherichia coli (ETEC). Cells were incubated with E. faecium, ETEC, or both, and the effects on barrier function and structure and intra- and intercellular signaling were determined. Coincubation with E. faecium abolished the ETEC-induced decrease in transepithelial resistance (R_t) (p ≤ 0.05). No differences were seen in the expression levels of the intercellular connecting tight junction proteins examined. However, for the first time, a reorganization of the monolayer was observed in ETEC-infected cells but not in coincubated cells. ETEC induced an increase in cytotoxicity that was prevented by coincubation (p ≤ 0.05), whereas apoptosis rates were not affected by bacterial treatment. ETEC increased the mRNA expression and release of proinflammatory cytokines TNF-α, IL-1α, and IL-6 which could be prevented by coincubation for TNF-α mRNA expression and IL-6 protein (p ≤ 0.05). Likewise, cAMP concentrations elevated by ETEC were reduced in coincubated cells (p ≤ 0.05). These findings indicate a protective effect of the probiotic E. faecium on inflammatory responses during infection with ETEC.

Apoptosis, Dysbiosis and Expression of Inflammatory Cytokines are Sequential Events in the Development of 5-Fluorouracil-Induced Intestinal Mucositis in Mice

The chemotherapeutic agent 5-fluorouracil (5-FU) causes intestinal mucositis with severe diarrhoea, but the pathogenesis is not fully understood. In this study, we investigated the pathogenic effects of 5-FU in mice, focusing on apoptosis, enterobacteria and inflammatory cytokines. Repeated administration of 5-FU caused severe intestinal mucositis on day 6, accompanied by diarrhoea and body-weight loss. TNF-α expression increased 1 day after exposure to the drug, and spiked a second time on day 4, at which point myeloperoxidase activity and IL-1β expression also increased. Apoptotic cells were observed in intestinal crypts only on day 1. 5-FU also induced dysbiosis, notably decreasing the abundance of intestinal Firmicutes while increasing the abundance of Bacteroidetes and Verrucomicrobia. Twice-daily co-administration of oral antibiotics significantly reduced the severity of intestinal mucositis and dysbiosis, and blocked the increase in myeloperoxidase activity and cytokine expression on day 6, without affecting apoptosis and TNF-α up-regulation on day 1. In cultured colonic epithelial cells, exposure to 5-FU also up-regulated TNF-α expression. Collectively, the data suggest that crypt apoptosis, dysbiosis and expression of inflammatory cytokines are sequential events in the development of intestinal mucositis after exposure to 5-FU. In particular, 5-FU appears to directly induce apoptosis via TNF-α and to suppress intestinal cell proliferation, thereby resulting in degradation of the epithelial barrier, as well as in secondary inflammation mediated by inflammatory cytokines.

Activation of muscarinic receptors prevents TNF-α-mediated intestinal epithelial barrier disruption through p38 MAPK

Intestinal epithelial cells form a tight barrier to act as selective physical barriers, repelling hostile substances. Tumor necrosis factor-α (TNF-α) is a well characterized pro-inflammatory cytokine which can compromise intestinal barrier function and the suppression of TNF-α function is important for treatment of inflammatory bowel disease (IBD). In this study, we investigated the contribution of G-protein-coupled receptor (GPCR)-induced signalling pathways to the maintenance of epithelial barrier function. We first demonstrated the existence of functional muscarinic M3 and histamine H1 receptors in colonic epithelial cell HT-29/B6. As we previously reported, muscarinic M3 receptor prevented TNF-α-induced barrier disruption through acceleration of TNF receptor (TNFR) shedding which is carried out by TNF-α converting enzyme (TACE). M3 receptor-mediated suppression of TNF-α function depends on Gα_q/11 protein, however, histamine H1 receptor could not ameliorate TNF-α function, while which could induce Gα_q/11 dependent intracellular Ca²⁺ mobilization. We found that p38 MAPK was predominantly phosphorylated by M3 receptor through Gα_q/11 protein, whereas H1 receptor barely upregulated the phosphorylation. Inhibition of p38 MAPK abolished M3 receptor-mediated TNFR shedding and suppression of TNF-α-induced NF-κB signalling. The p38 MAPK was also involved in TACE- mediated EGFR transactivation followed by ERK1/2 phosphorylation. These results indicate that not H1 but M3 receptor-induced activation of p38 MAPK might contribute to the maintenance of epithelial barrier function through down-regulation of TNF-α signalling and activation of EGFR.

A pathogenic role for T cell-derived IL-22BP in inflammatory bowel disease

Intestinal inflammation can impair mucosal healing, thereby establishing a vicious cycle leading to chronic inflammatory bowel disease (IBD). However, the signaling networks driving chronic inflammation remain unclear. Here we report that CD4⁺ T cells isolated from patients with IBD produce high levels of interleukin-22 binding protein (IL-22BP), the endogenous inhibitor of the tissue-protective cytokine IL-22. Using mouse models, we demonstrate that IBD development requires T cell-derived IL-22BP. Lastly, intestinal CD4⁺ T cells isolated from IBD patients responsive to treatment with antibodies against tumor necrosis factor-α (anti-TNF-α), the most effective known IBD therapy, exhibited reduced amounts of IL-22BP expression but still expressed IL-22. Our findings suggest that anti-TNF-α therapy may act at least in part by suppressing IL-22BP and point toward a more specific potential therapy for IBD.

TWEAK is not elevated in patients with newly diagnosed inflammatory bowel disease

OBJECTIVE

Tumor necrosis factor-like weak inducer of apoptosis (TWEAK) may be involved in the pathogenesis of inflammatory bowel disease. The aim was to investigate if TWEAK may reflect disease activity in inflammatory bowel disease.

MATERIALS AND METHODS

In this cohort study, 139 consecutive patients with newly diagnosed and previously untreated inflammatory bowel disease - 95 with ulcerative colitis (UC) and 44 with Crohn's disease (CD) - underwent colonoscopy. Disease activity was assessed by the Mayo score and the Mayo endoscopic score (MES) for UC, or the Simple Endoscopic Score (SES) for CD. Serum C-reactive protein (CRP) and fecal calprotectin were measured in IBD patients, as were plasma TWEAK levels in patients and 85 healthy subjects. Associations between TWEAK levels and disease activity markers were explored.

RESULTS

In the total IBD group, the median (interquartile range) TWEAK level was 430 pg/ml (109-6570), in UC 502 pg/ml (109-4547) and in CD patients 352 pg/ml (101-9179), respectively. Healthy subjects had a median (IQR) TWEAK of 307 pg/ml (63-3492). There were no significant differences in TWEAK levels between the total IBD group and healthy control subjects, nor between UC and CD, or between UC/CD and healthy subjects. Furthermore, we found no significant associations between Mayo scores, MES-UC, SES-CD, CRP, and fecal calprotectin with plasma TWEAK levels.

CONCLUSIONS

Plasma TWEAK levels do not reflect disease activity or the grade of inflammation in patients with newly diagnosed inflammatory bowel disease. NCT01551563.

Well-differentiated adenocarcinoma associated with ulcerative colitis

Objectives:

Adenocarcinoma is known to be associated with ulcerative colitis, but the diagnosis is sometimes challenging, both clinically and pathologically.

Methods and Results:

We present a case of extremely well-differentiated adenocarcinoma associated with ulcerative colitis, in which preoperative diagnosis was not possible. Glands in biopsy specimens showed a serrated appearance that looked like low-grade dysplasia or regenerative mucosa. After an operation due to severe symptoms of stenosis, carcinoma was diagnosed. Tumor cells, especially in invasive glands, tended to show stronger immunoreactivity against anti-CK7, TNF-α and Aurora B antibodies compared to cells of mucosal lesion. Interestingly, CD44v6, one of the adhesion molecules, was less expressed in invasive glands, while those glands exhibited stronger expression of a disintegrin and metalloproteinase 17 (ADAM 17), one of the sheddases that cleaves an extracellular domain of CD44.

Conclusions:

These observations appear interesting to consider the pathogenesis and to diagnose extremely well-differentiated adenocarcinoma in ulcerative colitis, although further investigation is needed.

Identification of Candidate Genes Related to Inflammatory Bowel Disease Using Minimum Redundancy Maximum Relevance, Incremental Feature Selection, and the Shortest-Path Approach

Identification of disease genes is a hot topic in biomedicine and genomics. However, it is a challenging problem because of the complexity of diseases. Inflammatory bowel disease (IBD) is an idiopathic disease caused by a dysregulated immune response to host intestinal microflora. It has been proven to be associated with the development of intestinal malignancies. Although the specific pathological characteristics and genetic background of IBD have been partially revealed, it is still an overdetermined disease and the blueprint of all genetic variants still needs to be improved. In this study, a novel computational method was built to identify genes related to IBD. Samples from two subtypes of IBD (ulcerative colitis and Crohn's disease) and normal samples were employed. By analyzing the gene expression profiles of these samples using minimum redundancy maximum relevance and incremental feature selection, 21 genes were obtained that could effectively distinguish samples from the two subtypes of IBD and the normal samples. Then, the shortest-path approach was used to search for an additional 20 genes in a large network constructed using protein-protein interactions based on the above-mentioned 21 genes. Analyses of the 41 genes obtained indicate that they are closely associated with this disease.

Genetic variation in IBD: progress, clues to pathogenesis and possible clinical utility

Epidemiological and clinical studies have suggested that the pathogenesis of inflammatory bowel disease (IBD) is strongly influenced by genetic predisposition. Beyond the limitations of linkage analysis, multiple genome-wide association studies, their meta-analyses, and targeted genotyping array techniques have broadened our understanding of the genetic architecture of IBD. Currently, over 200 single nucleotide polymorphisms are known to be associated with susceptibility to IBD and through functional analysis of genes and loci, a substantial proportion of pathophysiologic mechanisms have been revealed. However, because only a modest fraction of predicted heritability can be explained by known genes/loci, additional strategies are needed including the identification of rare variants with large effect sizes to help explain the missing heritability. Considerable progress is also being made on applying outcomes of genetic research in diagnostics, classification, prognostics, and the development of new therapeutics of IBD.