Therapeutic Targets in Inflammatory Bowel Disease: Current and Future

The FOXP3+ Pro-Inflammatory T Cell: A Potential Therapeutic Target in Crohn's Disease

BACKGROUND & AIMS

The incidence of Crohn's disease (CD) continues to increase worldwide. The contribution of CD4+ cell populations remains to be elucidated. We aimed to provide an in-depth transcriptional assessment of CD4+ T cells driving chronic inflammation in CD.

METHODS

We performed single-cell RNA-sequencing in CD4+ T cells isolated from ileal biopsies of patients with CD compared with healthy individuals. Cells underwent clustering analysis, followed by analysis of gene signaling networks. We overlapped our differentially expressed genes with publicly available microarray data sets and performed functional in vitro studies, including an in vitro suppression assay and organoid systems, to model gene expression changes observed in CD regulatory T (Treg) cells and to test predicted therapeutics.

RESULTS

We identified 5 distinct FOXP3+ regulatory Treg subpopulations. Tregs isolated from healthy controls represent the origin of pseudotemporal development into inflammation-associated subtypes. These proinflammatory Tregs displayed a unique responsiveness to tumor necrosis factor-α signaling with impaired suppressive activity in vitro and an elevated cytokine response in an organoid coculture system. As predicted in silico, the histone deacetylase inhibitor vorinostat normalized gene expression patterns, rescuing the suppressive function of FOXP3+ cells in vitro.

CONCLUSIONS

We identified a novel, proinflammatory FOXP3+ T cell subpopulation in patients with CD and developed a pipeline to specifically target these cells using the US Food and Drug Administration-approved drug vorinostat.

Microencapsulation as a Protective Strategy for Sialylated Immunoglobulin G: Efficacy in Alleviating Symptoms of Dextran Sulfate Sodium-Induced Colitis in Mice and Potential Mechanisms

Sialylated immunoglobulin G (IgG) is a vital glycoprotein in breast milk with the ability to promote the growth of Bifidobacterium in gut microbiota and relieve inflammatory bowel disease (IBD) symptoms in vitro. Here, it was found that the microcapsules with sialylated IgG could protect and release sialylated IgG with its structure and function in the intestine. Furthermore, the sialylated IgG microcapsules alleviated the clinical symptoms (body weight, feed quantity, and colon length loss), decreased disease activity index score, suppressed the production of pro-inflammatory cytokines (TNF-α, IL-6, IL-1β, IFN-γ, and MCP-1) and endotoxin (lipopolysaccharide), and enhanced the intestinal mucosal barrier (Claudin1, Muc2, Occludin, and ZO-1) in dextran sulfate sodium (DSS)-induced colitis mice. Additionally, the sialylated IgG microcapsules improved the gut microbiota by increasing the relative abundance of critical microbe Bifidobacterium bifidum and promoted the production of short-chain fatty acids (SCFAs). Correlation analysis indicated that the key microbes were strongly correlated with pro-inflammatory factors, clinical symptoms, tight junction protein, and SCFAs. These findings suggest that the sialylated IgG microcapsules have the potential to be used as a novel therapeutic approach for treating IBD.

Long-term safety of brazikumab in the open-label period of a randomized phase 2a study of patients with Crohn's disease

BACKGROUND

Short-term efficacy and safety of brazikumab (MEDI2070), a human monoclonal antibody and anti-p19 subunit inhibitor of interleukin-23, was demonstrated in a phase 2a trial in patients with moderate-to-severe active Crohn's disease (CD). We report brazikumab long-term safety and tolerability from the open-label period of this phase 2a study.

METHODS

Patients who completed the 12-week, double-blind induction period were eligible for inclusion in an open-label period where all patients received subcutaneous brazikumab (210 mg) every 4 weeks for 100 weeks. Patients had moderate-to-severe active CD and had failed or were intolerant to ≥ 1 anti-tumour necrosis factor alpha (TNFα) agent. Safety assessments included treatment-emergent adverse events (TEAEs); further assessments were pharmacokinetics and immunogenicity.

RESULTS

Of the 104 patients who entered the open-label period, 57 (54.8%) continued to the end of the open-label period and 47 (45.2%) discontinued brazikumab. The most common reasons for discontinuation were lack of response (14.4%), patient decision (12.5%), and TEAEs (11.5%). In total, 44 (84.6%) in the group switching from placebo to brazikumab (placebo/brazikumab) and 43 (82.7%) in the group continuing brazikumab (brazikumab/brazikumab) experienced 1 or more TEAEs. Most TEAEs were mild-to-moderate in severity. Common TEAEs included nasopharyngitis and headache. Numbers of treatment-emergent serious adverse events (TESAEs) were similar between groups. Infections occurred in 40.4% of patients in the placebo/brazikumab group and 50% in the brazikumab/brazikumab group. There were 5 TESAEs of infection, none of which were opportunistic. No major adverse cardiac events, malignancies, or deaths were reported.

CONCLUSIONS

Brazikumab was well tolerated with an acceptable safety profile over a 100-week period in patients with moderate-to-severe active CD who failed or were intolerant to 1 or more anti-TNFα agents.

TRIAL REGISTRATION

NCT01714726; registered October 26, 2012.

Landscape of sialylation patterns identify biomarkers for diagnosis and prediction of response to anti-TNF therapy in crohn's disease

Crohn's disease (CD), a subtype of inflammatory bowel disease (IBD), causes chronic gastrointestinal tract inflammation. Thirty percent of patients do not respond to anti-tumor necrosis factor (TNF) therapy. Sialylation is involved in the pathogenesis of IBD. We aimed to identify potential biomarkers for diagnosing CD and predicting anti-TNF medication outcomes in CD. Three potential biomarkers (SERPINB2, TFPI2, and SLC9B2) were screened using bioinformatics analysis and machine learning based on sialylation-related genes. Moreover, the combined model of SERPINB2, TFPI2, and SLC9B2 showed excellent diagnostic value in both the training and validation cohorts. Importantly, a Sial-score was constructed based on the expression of SERPINB2, TFPI2, and SLC9B2. The Sial-low group showed a lower level of immune infiltration than the Sial-high group. Anti-TNF therapy was effective for 94.4% of patients in the Sial-low group but only 15.8% in the Sial-high group. The Sial-score had an outstanding ability to predict and distinguish between responders and non-responders. Our comprehensive analysis indicates that SERPINB2, TFPI2, and SLC9B2 play essential roles in pathogenesis and anti-TNF therapy resistance in CD. Furthermore, it may provide novel concepts for customizing treatment for individual patients with CD.

Context-Dependent Regulation of Type17 Immunity by Microbiota at the Intestinal Barrier

T-helper-17 (Th17) cells and related IL-17-producing (type17) lymphocytes are abundant at the epithelial barrier. In response to bacterial and fungal infection, the signature cytokines IL-17A/F and IL-22 mediate the antimicrobial immune response and contribute to wound healing of injured tissues. Despite their protective function, type17 lymphocytes are also responsible for various chronic inflammatory disorders, including inflammatory bowel disease (IBD) and colitis associated cancer (CAC). A deeper understanding of type17 regulatory mechanisms could ultimately lead to the discovery of therapeutic strategies for the treatment of chronic inflammatory disorders and the prevention of cancer. In this review, we discuss the current understanding of the development and function of type17 immune cells at the intestinal barrier, focusing on the impact of microbiota-immune interactions on intestinal barrier homeostasis and disease etiology.

Pharmacogenetic analysis of canonical versus noncanonical pathway of NF-kB in Crohn's disease patients under anti-tumor necrosis factor-α treatment

OBJECTIVES

This study explores the potential of gene polymorphisms in the canonical and noncanonical NF-kB signaling pathway as a prediction biomarker of anti-tumor necrosis factor (TNF)α response in Crohn's patients.

MATERIALS AND METHODS

A total of 109 Greek patients with Crohn's disease (CD) were recruited, and the genotype of TLR2 rs3804099, LTA rs909253, TLR4 rs5030728, and MAP3K14/NIK rs7222094 single nucleotide polymorphisms was investigated for association with response to anti-TNFα therapy. Patient's response to therapy was based on the Crohn's Disease Activity Index, depicting the maximum response within 24 months after initiation of treatment.

RESULTS

Seventy-three patients (66.7%) were classified as responders while 36 as nonresponders (33.3%). Comparing allelic frequencies between responders and nonresponders, the presence of TLR2 rs3804099 T allele was associated with nonresponse (P = 0.003), even after stratification by anti-TNFα drugs (infliximab: P = 0.032, adalimumab: P = 0.026). No other association was identified for the rest of the polymorphisms under study. Haplotype analysis further enhanced the association of rs3804099 T allele with loss of response, even though the results were NS (P = 0.073).

CONCLUSION

Our results suggest that polymorphisms in the canonical NF-kB pathway genes could potentially act as a predictive biomarker of anti-TNFα response in CD.

Mucus-Penetrating Alginate-Chitosan Nanoparticles Loaded with Berberine Hydrochloride for Oral Delivery to the Inflammation Site of Ulcerative Colitis

The rectal enemas of berberine hydrochloride (BH) have emerged as one of the most effective strategies in the clinical treatment of ulcerative colitis (UC). However, oral dosages of BH exhibit a poor anti-inflammatory effect of UC, which may attribute to premature absorption of BH by the upper gastrointestinal tract. Moreover, the thick colonic mucus layer obstructs the penetration of the drug, resulting in low bioavailability to the inflammatory site of the colon. The aim of this study was to develop the mucus-penetrating sodium alginate-chitosan nanoparticles (SA-CS NPs) for oral delivery of BH to the site of colonic ulcer lesions. BH-loaded SA-CS NPs were developed through the ionic gelation method and analyzed for physicochemical characteristics, release performance, penetrability, site retention, and therapeutic efficacy. The results showed that the NPs have a particle size of 257 nm with a negative charge, presenting desired pH-dependent release behavior. The permeation studies elucidated that negatively charged SA-CS NPs had 2.9 times higher mucus penetration ability than positively charged CS NPs. An ex vivo retention study indicated the high retention of BH-SA-CS NPs at the colon site for more than 16 h. In vivo therapeutic effectiveness demonstrated that the prepared NPs could not only alleviate colonic injury by decreasing the disease activity index and colon mucosa damage index, but also improve the immunologic function by decreasing the spleen index. In conclusion, the BH-SA-CS NPs could enhance the mucus permeability and deliver drugs to the colonic inflammation site, providing new insights into improving the therapeutic effect of UC.

A method for the inference of cytokine interaction networks

Cell-cell communication is mediated by many soluble mediators, including over 40 cytokines. Cytokines, e.g. TNF, IL1β, IL5, IL6, IL12 and IL23, represent important therapeutic targets in immune-mediated inflammatory diseases (IMIDs), such as inflammatory bowel disease (IBD), psoriasis, asthma, rheumatoid and juvenile arthritis. The identification of cytokines that are causative drivers of, and not just associated with, inflammation is fundamental for selecting therapeutic targets that should be studied in clinical trials. As in vitro models of cytokine interactions provide a simplified framework to study complex in vivo interactions, and can easily be perturbed experimentally, they are key for identifying such targets. We present a method to extract a minimal, weighted cytokine interaction network, given in vitro data on the effects of the blockage of single cytokine receptors on the secretion rate of other cytokines. Existing biological network inference methods typically consider the correlation structure of the underlying dataset, but this can make them poorly suited for highly connected, non-linear cytokine interaction data. Our method uses ordinary differential equation systems to represent cytokine interactions, and efficiently computes the configuration with the lowest Akaike information criterion value for all possible network configurations. It enables us to study indirect cytokine interactions and quantify inhibition effects. The extracted network can also be used to predict the combined effects of inhibiting various cytokines simultaneously. The model equations can easily be adjusted to incorporate more complicated dynamics and accommodate temporal data. We validate our method using synthetic datasets and apply our method to an experimental dataset on the regulation of IL23, a cytokine with therapeutic relevance in psoriasis and IBD. We validate several model predictions against experimental data that were not used for model fitting. In summary, we present a novel method specifically designed to efficiently infer cytokine interaction networks from cytokine perturbation data in the context of IMIDs.

Cytokines are the messenger molecules of the immune system, allowing intercellular communication and mediating effective immune responses. They are an important therapeutic target in immune mediated inflammatory diseases such as inflammatory bowel disease (IBD) and rheumatoid arthritis. Cytokines interact in a tightly regulated network and depending on the context a particular cytokine can be involved in anti-inflammatory or inflammatory activities. In order to determine which cytokines to target in specific disease types and patient subsets, it is critical to study the effects of the inhibition of one or more cytokines on the larger cytokine interaction network. We present a novel method to extract a minimal, weighted network from cytokine interaction data. Existing biological network inference methods typically consider the correlation structure of the underlying dataset and/or make further assumptions of the dataset such as the existence of a small core of regulators. This can make them poorly suited for highly connected, non-linear cytokine interaction data. We validated our method using synthetic data and applied our method to a dataset on the regulation of IL23, a cytokine implicated in IBD pathogenesis. Predictions of the extracted IL23 network were validated using additional experimental data and were used to support the view of the cytokines IL1 and IL23 as promising targets for those patients that fail to respond to TNFα inhibition, the current golden standard in IBD treatment.

Upadacitinib Treatment Improves Symptoms of Bowel Urgency and Abdominal Pain, and Correlates With Quality of Life Improvements in Patients With Moderate to Severe Ulcerative Colitis

BACKGROUND AND AIMS

Bowel urgency and abdominal pain are impactful, yet under-appreciated ulcerative colitis symptoms and not commonly assessed in clinical trials. We evaluated how these symptoms may improve with upadacitinib treatment and correlate with clinical and health-related quality of life [HRQOL] outcomes in the phase 2b U-ACHIEVE study.

METHODS

Patients aged 18-75 years, with moderately to severely active ulcerative colitis, were randomised to receive placebo or upadacitinib (7.5, 15, 30, or 45 mg once daily [QD]). Bowel urgency and abdominal pain were evaluated at baseline and Weeks 2, 4, 6, and 8. Week 8 correlations were evaluated between bowel urgency/abdominal pain with clinical [Mayo subscores and high-sensitivity C-reactive protein and faecal calprotectin measurements] and HRQOL outcomes [Inflammatory Bowel Disease Questionnaire and 36-Item Short Form Health Survey scores].

RESULTS

A greater proportion of patients [n = 250] reported no bowel urgency and less abdominal pain with upadacitinib treatment compared with placebo, with improvements observed as early as 2 weeks. At Week 8, patients receiving the 45-mg QD dose had the greatest improvements versus placebo, with 46% reporting no bowel urgency [vs 9%; p ≤ 0.001] and 38% reporting no abdominal pain [vs 13%; p = 0.015]. At Week 8, moderate correlations were found between bowel urgency or abdominal pain and most clinical and HRQOL outcomes.

CONCLUSIONS

Induction treatment with upadacitinib demonstrated significant reductions in bowel urgency and abdominal pain compared with placebo. These symptoms also correlate to clinical and HRQOL outcomes, supporting their use to monitor disease severity and other treatment outcomes.

Targeting strategies of oral nano-delivery systems for treating inflammatory bowel disease

Inflammatory bowel disease (IBD) is a chronic relapsing inflammatory disorder of gastrointestinal tract with rising incidence. Established treatments of IBD are characterized by significantly adverse effects, insufficient therapeutic efficacy. Employing the oral nano-drug delivery systems for targeted therapy is capable of effectively avoiding systematic absorption and increasing local drug concentration, consequently leading to decreased adverse effects and improved therapeutic outcomes. This review gives a brief profile of pathophysiological considerations in terms of developing disease-directed drug delivery systems, then focuses on mechanisms and strategies of current oral nano-drug delivery systems, including size-, enzyme-, redox-, pH-, ligand-receptor-, mucus-dependent systems, and proposes the future directions of managements for IBD.

Interleukin 10 and interleukin 10 receptor in paediatric inflammatory bowel disease: from bench to bedside lesson

Background

The differences between adults and children in inflammatory bowel disease (IBD) phenotype, severity, complications, co-morbidities, and response to the therapy resulted in the extraction of paediatric IBD. It has been revealed that the substantial role in the development of IBD in children under 6 years of age plays a single genetic mutation (monogenic IBD). On the other hand, in older children and adolescents IBD is usually associated with number of interactions between susceptibility loci (polygenic IBD).

Main body

Until now there have been described about 60 monogenic defects which affect the variety of immune mechanisms in IBD pathogenesis including epithelial barrier, function of neutrophil granulocytes and phagocytes, T- and B-cell selection and activation, immune inhibitory mechanisms, or apoptosis. Il-10 is an anti-inflammatory cytokine which modulates innate and adaptive immunity affecting expression of pro-inflammatory molecules and function of the variety of immune cells. Patients with identified defects in Il-10 pathway manifest with life-threating colitis with perianal lesions which occurs within first months of life. Allogenic hematopoietic stem cell transplantation is curative therapy in children with Il-10 signalling defects.

Conclusion

Clinical awareness of Il-10 signalling defects enables early recognition and prompt management of the disease.

Oxidants in Physiological Processes

A number of diseases and conditions have been associated with prolonged or persistent exposure to non-physiological levels of reactive oxygen species (ROS). Similarly, ROS underproduction due to loss-of-function mutations in superoxide or hydrogen peroxide (H₂O₂)-generating enzymes is a risk factor or causative for certain diseases. However, ROS are required for basic cell functions; in particular the diffusible second messenger H₂O₂ that serves as signaling molecule in redox processes. This activity sets H₂O₂ apart from highly reactive oxygen radicals and influences the approach to drug discovery, clinical utility, and therapeutic intervention. Here we review the chemical and biological fundamentals of ROS with emphasis on H₂O₂ as a signaling conduit and initiator of redox relays and propose an integrated view of physiological versus non-physiological reactive species. Therapeutic interventions that target persistently altered ROS levels should include both selective inhibition of a specific source of primary ROS and careful consideration of a targeted pro-oxidant approach, an avenue that is still underdeveloped. Both strategies require attention to redox dynamics in complex cellular systems, integration of the overall spatiotemporal cellular environment, and target validation to yield effective and safe therapeutics. The only professional primary ROS producers are NADPH oxidases (NOX1-5, DUOX1-2). Many other enzymes, e.g., xanthine oxidase (XO), monoamine oxidases (MAO), lysyl oxidases (LO), lipoxygenase (LOX), and cyclooxygenase (COX), produce superoxide and H₂O₂ secondary to their primary metabolic function. Superoxide is too reactive to disseminate, but H₂O₂ is diffusible, only limited by adjacent PRDXs or GPXs, and can be apically secreted and imported into cells through aquaporin (AQP) channels. H₂O₂ redox signaling includes oxidation of the active site thiol in protein tyrosine phosphatases, which will inhibit their activity and thereby increase tyrosine phosphorylation on target proteins. Essential functions include the oxidative burst by NOX2 as antimicrobial innate immune response; gastrointestinal NOX1 and DUOX2 generating low H₂O₂ concentrations sufficient to trigger antivirulence mechanisms; and thyroidal DUOX2 essential for providing H₂O₂ reduced by TPO to oxidize iodide to an iodinating form which is then attached to tyrosyls in TG. Loss-of-function (LoF) variants in TPO or DUOX2 cause congenital hypothyroidism and LoF variants in the NOX2 complex chronic granulomatous disease.

Recent Advances in Therapeutic Applications of Bisbenzimidazoles

Nitrogen-containing heterocycles are one of the most common structural motifs in approximately 80% of the marketed drugs. Of these, benzimidazoles analogues are known to elicit a wide spectrum of pharmaceutical activities such as anticancer, antibacterial, antiparasitic, antiviral, antifungal as well as chemosensor effect. Based on the benzimidazole core fused heterocyclic compounds, crescent-shaped bisbenzimidazoles were developed which provided an early breakthrough in the sequence-specific DNA recognition. Over the years, a number of functional variations in the bisbenzimidazole core have led to the emergence of their unique properties and established them as versatile ligands against several classes of pathogens. The present review provides an overview of diverse pharmacological activities of the bisbenzimidazole analogues in the past decade with a brief account of its development through the years.

NOD2 deficiency increases retrograde transport of secretory IgA complexes in Crohn's disease

Intestinal microfold cells are the primary pathway for translocation of secretory IgA (SIgA)-pathogen complexes to gut-associated lymphoid tissue. Uptake of SIgA/commensals complexes is important for priming adaptive immunity in the mucosa. This study aims to explore the effect of SIgA retrograde transport of immune complexes in Crohn's disease (CD). Here we report a significant increase of SIgA transport in CD patients with NOD2-mutation compared to CD patients without NOD2 mutation and/or healthy individuals. NOD2 has an effect in the IgA transport through human and mouse M cells by downregulating Dectin-1 and Siglec-5 expression, two receptors involved in retrograde transport. These findings define a mechanism of NOD2-mediated regulation of mucosal responses to intestinal microbiota, which is involved in CD intestinal inflammation and dysbiosis.

Evaluation of Anti-Colitis Effect of KM1608 and Biodistribution of Dehydrocostus Lactone in Mice Using Bioimaging Analysis

Inflammatory bowel disease (IBD) is a chronic relapsing disorder modulated by numerous factors. Recent failures of drugs targeting single factors suggest that multitargeting drugs could be useful for the treatment of IBD. Natural medicines may be an alternative option for the treatment of IBD, owing to the complex nature of the disease. However, most natural medicines have poor in vitro and in vivo translational potential because of inadequate pharmacokinetic study. KM1608, a mixture of the medicinal plants Aucklandia lappa, Terminalia chebula, and Zingiber officinale, was examined for its anti-colitis effects and biodistribution using bioimaging. Dehydrocostus lactone, as a marker compound, was analyzed to assess the biodistribution of KM1608. KM1608 significantly attenuated the disease activity of dextran sodium sulfate-induced colitis in mice and suppressed inflammatory mediators such as myeloperoxidase, proinflammatory cytokines (TNF-α and IL-6), and the Th2-type cytokine IL-4 in the colon. Optical fluorescence imaging revealed that KM1608 was distributed in the intestinal area as a target organ. Collectively, our findings suggest that KM1608 is a potential therapeutic formulation for IBD.

A Dynamic Quantitative Systems Pharmacology Model of Inflammatory Bowel Disease: Part 2 - Application to Current Therapies in Crohn's Disease

Inflammatory bowel disease (IBD) is a heterogeneic disease with a variety of treatments targeting different mechanisms. A multistate, mechanistic, mathematical model of IBD was developed in part 1 of this two-part article series. In this paper, application of the model to predict response of key clinical biomarkers following different treatment options for Crohn's disease was explored. Five therapies, representing four different mechanisms of action, were simulated in the model and longitudinal profiles of key clinical markers, C-reactive protein and fecal calprotectin were compared with clinical observations. Model simulations provided an accurate match with both central tendency and variability observed in biomarker profiles. We also applied the model to predict biomarker and clinical response in an experimental, combination therapy of existing therapeutic options and provide possible mechanistic basis for the increased response. Overall, we present a validated, modular, mechanistic model construct, which can be applied to explore key biomarkers and clinical outcomes in IBD.

The development of colitis in Il10-/- mice is dependent on IL-22

Mice deficient in the IL-10 pathway are the most widely used models of intestinal immunopathology. IL-17A is strongly implicated in gut disease in mice and humans, but conflicting evidence has drawn IL-17's role in the gut into question. IL-22 regulates antimicrobial and repair activities of intestinal epithelial cells (IECs) and is closely associated with IL-17A responses but it's role in chronic disease is uncertain. We report that IL-22, like IL-17A, is aberrantly expressed in colitic Il10-/- mice. While IL-22+ Th17 cells were elevated in the colon, IL-22-producing ILC3s were highly enriched in the small intestines of Il10-/- mice. Remarkably, Il10-/-Il22-/- mice did not develop colitis despite retaining high levels of Th17 cells and remaining colonized with colitogenic Helicobacter spp. Accordant with IL-22-induced IEC proliferation, the epithelia hyperplasia observed in Il10-/- animals was reversed in Il10-/-Il22-/- mice. Also, the high levels of antimicrobial IL-22-target genes, including Reg3g, were normalized in Il10-/-Il22-/- mice. Consistent with a heightened antimicrobial environment, Il10-/- mice had reduced diversity of the fecal microbiome that was reestablished in Il10-/-Il22-/- animals. These data suggest that spontaneous colitis in Il10-/- mice is driven by IL-22 and implicates an underappreciated IL-10/IL-22 axis in regulating intestinal homeostasis.

Bioactive indanes: insight into the bioactivity of indane dimers related to the lead anti-inflammatory molecule PH46A

Objectives

PH46A (1) demonstrates significant anti-inflammatory activity in phenotypic models but its mechanism and site of action have been elusive. Current study focused on the bioactivity of PH46 (2) and related novel indane dimers (6-10) to investigate the impact of changes in substitution and stereochemistry at the C-1 and C-2 positions of the PH46 (2) scaffold.

Methods

Cytotoxicity profiles of compounds were established using THP-1 macrophages and SW480 cells. Effects of the compounds were then evaluated at 10 µm using 5-lipoxygenase (LOX) and 15-LOX enzymes, and 5-LOX binding was evaluated in silico against NDGA, nitric oxide (NO) released from LPS-induced SW480 cells and cytokines in THP-1 macrophages (IL-6, IL-1β, TNF-α and IFN-γ) and in SW480 cells (IL-8).

Key findings

PH46 (2) and 7 cause reduction in NO, inhibition of 5-LOX with high binding energy and no cytotoxicity effects in THP-1 macrophages and SW480 cell lines (up to 50 µm). The cytokine profiling of the series demonstrated inhibition of IL-6 and TNF-α in THP-1 macrophages together with IL-8 in SW480 cells.

Conclusions

The observed profile of cytokine modulation (IL-6/ TNF-α, IL-8) and inhibition of release of NO and 5-LOX may contribute to the in vivo effects demonstrated by indane dimers and PH46A (1) in murine models of colitis.

Inflammatory bowel disease: between genetics and microbiota

Inflammatory bowel disease (IBD) is a chronic relapsing inflammatory disease that can involve any part of the gastrointestinal tract. It includes two main disorders: Crohn's disease (CD) and Ulcerative colitis (UC). CD and UC often share a similar clinical presentation; however, they affect distinct parts of the GI Tract with a different gut wall inflammatory extent. Ultimately, IBD seems to emanate from an uncontrollably continuous inflammatory process arising against the intestinal microbiome in a genetically susceptible individual. It is a multifactorial disease stemming from the impact of both environmental and genetic components on the intestinal microbiome. Furthermore, IBD genetics has gained a lot of attention. Around 200 loci were identified as imparting an increased risk for IBD. Few of them were heavily investigated and determined as highly linked to IBD. These genes, as discussed below, include NOD2, ATG16L1, IRGM, LRRK2, PTPN2, IL23R, Il10, Il10RA, Il10RB, CDH1 and HNF4α among others. Consequently, the incorporation of a genetic panel covering these key genes would markedly enhance the diagnosis and evaluation of IBD.

Human β-Defensin 2 Mediated Immune Modulation as Treatment for Experimental Colitis

Defensins represents an integral part of the innate immune system serving to ward off potential pathogens and to protect the intestinal barrier from microbial encroachment. In addition to their antimicrobial activities, defensins in general, and human β-defensin 2 (hBD2) in particular, also exhibit immunomodulatory capabilities. In this report, we assessed the therapeutic efficacy of systemically administered recombinant hBD2 to ameliorate intestinal inflammation in three distinct animal models of inflammatory bowel disease; i.e., chemically induced mucosal injury (DSS), loss of mucosal tolerance (TNBS), and T-cell transfer into immunodeficient recipient mice. Treatment efficacy was confirmed in all tested models, where systemically administered hBD2 mitigated inflammation, improved disease activity index, and hindered colitis-induced body weight loss on par with anti-TNF-α and steroids. Treatment of lipopolysaccharide (LPS)-activated human peripheral blood mononuclear cells with rhBD2 confirmed the immunomodulatory capacity in the circulatory compartment. Subsequent analyzes revealed dendritic cells (DCs) as the main target population. Suppression of LPS-induced inflammation was dependent on chemokine receptor 2 (CCR2) expression. Mechanistically, hBD2 engaged with CCR2 on its DC target cell to decrease NF-κB, and increase CREB phosphorylation, hence curbing inflammation. To our knowledge, this is the first study showing in vivo efficacy of a systemically administered defensin in experimental disease.

Engineered E. coli Nissle 1917 for the delivery of matrix-tethered therapeutic domains to the gut

Mucosal healing plays a critical role in combatting the effects of inflammatory bowel disease, fistulae and ulcers. While most treatments for such diseases focus on systemically delivered anti-inflammatory drugs, often leading to detrimental side effects, mucosal healing agents that target the gut epithelium are underexplored. We genetically engineer Escherichia coli Nissle 1917 (EcN) to create fibrous matrices that promote gut epithelial integrity in situ. These matrices consist of curli nanofibers displaying trefoil factors (TFFs), known to promote intestinal barrier function and epithelial restitution. We confirm that engineered EcN can secrete the curli-fused TFFs in vitro and in vivo, and is non-pathogenic. We observe enhanced protective effects of engineered EcN against dextran sodium sulfate-induced colitis in mice, associated with mucosal healing and immunomodulation. This work lays a foundation for the development of a platform in which the in situ production of therapeutic protein matrices from beneficial bacteria can be exploited.

Single-Cell Analysis of Crohn's Disease Lesions Identifies a Pathogenic Cellular Module Associated with Resistance to Anti-TNF Therapy

Clinical benefits of cytokine blockade in ileal Crohn's disease (iCD) are limited to a subset of patients. Here, we applied single-cell technologies to iCD lesions to address whether cellular heterogeneity contributes to treatment resistance. We found that a subset of patients expressed a unique cellular module in inflamed tissues that consisted of IgG plasma cells, inflammatory mononuclear phagocytes, activated T cells, and stromal cells, which we named the GIMATS module. Analysis of ligand-receptor interaction pairs identified a distinct network connectivity that likely drives the GIMATS module. Strikingly, the GIMATS module was also present in a subset of patients in four independent iCD cohorts (n = 441), and its presence at diagnosis correlated with failure to achieve durable corticosteroid-free remission upon anti-TNF therapy. These results emphasize the limitations of current diagnostic assays and the potential for single-cell mapping tools to identify novel biomarkers of treatment response and tailored therapeutic opportunities.

Impact of pain associated with the subcutaneous administration of adalimumab

BACKGROUND

There is limited information regarding the impact of patients' perception of injection pain on adherence to treatments, specifically in inflammatory bowel disease (IBD) patients. Therefore, we aimed to determine the impact of the pain associated with the subcutaneous administration of adalimumab in patients with IBD treated with the old formulation and the new low-volume/citrate-free formulation.

METHODS

A specifically-designed questionnaire was completed by 76 patients with IBD, who started treatment with adalimumab before the availability of the low-volume/citrate-free formulation and were switched to this new formulation. Intensity of pain was measured by using visual analog scales (VAS).

RESULTS

A total of 62 patients (82%) experienced injection-related pain with the initial formulation. The perception of pain was associated with a decreased adherence to the treatment (37%), an increase in pre-administration anxiety (25%) or, as a consequence, the patient required someone else to carry out the injection (21%). Younger age was the only factor associated with pain perception. After switching to the new formulation, perception of pain persisted only in 2 patients (3%). Among those who felt pain with the initial formulation, pre-administration anxiety disappeared in 44%; 32% and 42% stated that the new formulation eased adherence and self-administration.

CONCLUSIONS

The perception of pain related to the subcutaneous administration of therapy negatively impacts on treatment adherence in IBD patients. Improved formulations for subcutaneous administration of drugs can positively impact patients' convenience and adherence.

Ileal Gene Expression Data from Crohn's Disease Small Bowel Resections Indicate Distinct Clinical Subgroups

BACKGROUND AND AIMS

Heterogeneity in Crohn's disease [CD] provides a challenge for the development of effective therapies. Our goal was to define a unique molecular signature for severe, refractory CD to enable precision therapy approaches to disease treatment and to facilitate earlier intervention in complicated disease.

METHODS

We analysed clinical metadata, genetics, and transcriptomics from uninvolved ileal tissue from CD patients who underwent a single small bowel resection. We determined transcriptional risk scores, cellular signatures, and mechanistic pathways that define patient subsets in refractory CD.

RESULTS

Within refractory CD, we found three CD patient subgroups [CD1, CD2, and CD3]. Compared with CD1, CD3 was enriched for subjects with increased disease recurrence after first surgery [OR = 6.78, p = 0.04], enhanced occurrence of second surgery [OR = 5.07, p = 0.016], and presence of perianal CD [OR = 3.61, p = 0.036]. The proportion of patients with recurrence-free survival was smaller in CD3 than in CD1 (p = 0.02, median survival time [months] in CD1 = 10 and CD3 = 6). Overlaying differential gene expression between CD1 and CD3 on CD subgroup-associated genetic polymorphisms identified 174 genes representing both genetic and biological differences between the CD subgroups. Pathway analyses using this unique gene signature indicated eukaryotic initiation factor 2 [eIF2] and cyclic adenosine monophosphate [cAMP] signalling to be dominant pathways associated with CD3. Furthermore, the severe, refractory subset, CD3, was associated with a higher transcriptional risk score and enriched with eosinophil and natural killer T [NKT] cell gene signatures.

CONCLUSION

We characterized a subset of severe, refractory CD patients who may need more aggressive treatment after first resection and who are likely to benefit from targeted therapy based on their genotype and tissue gene expression signature.

Mass cytometry reveals systemic and local immune signatures that distinguish inflammatory bowel diseases

Inflammatory bowel disease (IBD) includes Crohn's disease and ulcerative colitis. Each disease is characterized by a diverse set of potential manifestations, which determine patients' disease phenotype. Current understanding of phenotype determinants is limited, despite increasing prevalence and healthcare costs. Diagnosis and monitoring of disease requires invasive procedures, such as endoscopy and tissue biopsy. Here we report signatures of heterogeneity between disease diagnoses and phenotypes. Using mass cytometry, we analyze leukocyte subsets, characterize their function(s), and examine gut-homing molecule expression in blood and intestinal tissue from healthy and/or IBD subjects. Some signatures persist in IBD despite remission, and many signatures are highly represented by leukocytes that express gut trafficking molecules. Moreover, distinct systemic and local immune signatures suggest patterns of cell localization in disease. Our findings highlight the importance of gut tropic leukocytes in circulation and reveal that blood-based immune signatures differentiate clinically relevant subsets of IBD.

Pathologic up-regulation of TNFSF15–TNFRSF25 axis sustains endothelial dysfunction in unprovoked venous thromboembolism

Aims

The pathogenetic mechanisms underlying unprovoked venous thromboembolism (uVTE) are largely unknown. In this study, we investigated the molecular mechanisms involved in uVTE pathogenesis by using ex vivo expanded endothelial colony-forming cells (ECFCs), which represent a valuable non-invasive tool for the assessment of endothelial function.

Methods and results

We isolated and expanded ECFCs from the peripheral blood of uVTE patients and observed that these cells underwent earlier senescence and showed lower growth rate compared with ECFCs obtained from healthy donors. Through microarray expression profiling, we demonstrated that 2905 genes were differentially expressed between patients and controls. Among them, the anti-angiogenic cytokine TNF superfamily member 15 (TNFSF15) and its death-receptor TNFRSF25 were up-regulated in uVTE ECFCs, and this finding was validated by RT-qPCR. TNFSF15 up-regulation was confirmed at the protein level in ECFC supernatants, and the in vivo relevance of these findings was further corroborated by demonstrating that also the plasmatic levels of TNFSF15 are increased in uVTE patients. After proving that exogenous TNFSF15 exerts pro-apoptotic and anti-proliferative activity on control ECFCs, we demonstrated through blocking experiments that TNFSF15 up-regulation contributes to impaired survival and proliferation of uVTE ECFCs.

Conclusion

By providing evidence that TNFSF15 impairs ECFC functions crucial to endothelial repair, and that uVTE patients have increased TNFSF15 levels both ex vivo and in vivo, the results of this study suggest that pathologic up-regulation of TNFSF15–TNFRSF25 axis may contribute to uVTE pathogenesis, and may represent the target for novel therapeutic strategies aimed at preventing recurrences in uVTE patients.

Interleukin-1β-induced IRAK1 ubiquitination is required for TH-GM-CSF cell differentiation in T cell-mediated inflammation

Accumulating evidence suggests granulocyte macrophage-colony stimulating factor (GM-CSF) can function as an inflammatory mediator, but whether GM-CSF-producing CD4⁺ T cells (T_H-GM-CSF) are a distinct T helper cell subset is lacking. Herein we demonstrate that interleukin (IL)-1β exclusively drives differentiation of naïve CD4⁺ T cells into T_H-GM-CSF cells via inducing ubiquitination of IL-1 receptor-associated kinase 1 (IRAK1) and subsequent activation of the transcription factor NF-kappaB (NF-κB), independent of RAR-related orphan receptor gamma (RORγt) required for T_H17 differentiation. In vivo, T_H-GM-CSF cells are present in murine Citrobacter Rodentium infections and mediate colitis following adoptive transfer of CD4⁺ T cells into Rag1^-/- mice via GM-CSF-induced macrophage activation. The T_H-GM-CSF cell phenotype is stable and distinct from the T_H17 genetic program, but IL-1β can convert pre-formed T_H17 cells into T_H-GM-CSF cells, thereby accounting for previously reported associations between IL-17 and GM-CSF. Together, our results newly identify IL-1β/NF-κB-dependent T_H-GM-CSF cells as a unique T helper cell subset and highlight the importance of CD4⁺ T cell-derived GM-CSF induced macrophage activation as a previously undescribed T cell effector mechanism.

Cross-Talk Between Antigen Presenting Cells and T Cells Impacts Intestinal Homeostasis, Bacterial Infections, and Tumorigenesis

Innate immunity is maintained in part by antigen presenting cells (APCs) including dendritic cells, macrophages, and B cells. APCs interact with T cells to link innate and adaptive immune responses. By displaying bacterial and tumorigenic antigens on their surface via major histocompatibility complexes, APCs can directly influence the differentiation of T cells. Likewise, T cell activation, differentiation, and effector functions are modulated by APCs utilizing multiple mechanisms. The objective of this review is to describe how APCs interact with and influence the activation of T cells to maintain innate immunity during exposure to microbial infection and malignant cells. How bacteria and cancer cells take advantage of some of these interactions for their own benefit will also be discussed. While this review will cover a broad range of topics, a general focus will be held around pathogens, cancers, and interactions that typically occur within the gastrointestinal tract.

Identification of New Potential Therapies for Colitis Amelioration Using an Appendicitis-Appendectomy Model

The appendix contains copious lymphoid tissue and is constantly exposed to gut flora. Appendicitis followed by appendectomy (AA), when done at a young age, prevents or significantly ameliorates inflammatory bowel diseases (IBDs) in later life. Inflammatory bowel disease comprises Crohn's disease and ulcerative colitis. Our unique murine AA model is the only existing experimental model of AA. Herein, the appendiceal pathology closely resembles the pathological features of human appendicitis. Our AA model protects against experimental colitis in an age-, bacteria- and antigen-dependent manner. Appendicitis-appendectomy performed in the most proximal colon curbs T helper 17 (Th17) cell activity, diminishes autophagy, modulates interferon activity-associated molecules, and suppresses endothelin vasoactivity-mediated immunopathology in the most distal colon. These changes induced by AA contribute to limiting colitis pathology. Manipulating and modulating various aspects of these pathways, pathophysiology, and molecular interactions will assist the development of novel therapeutic options to manage IBD. Competitive inhibition of the Th17 cell recruitment factor CCL20 or the chemokine CCL17 with antibodies, combinatorial peptides, or small molecules may limit colitic pathology. The chemokines CCL5 and CXCL11 could be investigated as potential therapies. Inhibition of the autophagy-associated molecules VPS15, LAMP2, LC3A, XBP1, or ULK1 may decrease colitic pathology. Curtailing endothelin-activity may decrease colitic impact. The antiproliferative, immunomodulatory molecules IFIT1, IFIT2, IFIT3, and IFI44 may have direct therapeutic value in ameliorating colitis. The molecules IRF4, IRF8, IRF2BP1, IFRD1, and IFRD2 are potentially good target molecules to competitively inhibit towards curbing colitis.

Preparation of Herbal Formulation for Inflammatory Bowel Disease Based on In Vitro Screening and In Vivo Evaluation in a Mouse Model of Experimental Colitis

Many medicinal plants have been used traditionally in East Asia for the treatment of gastrointestinal disease and inflammation. The aim of this study was to evaluate the anti-inflammatory activity of 350 extracts (175 water extracts and 175 ethanol extracts) from 71 single plants, 97 mixtures of two plants, and seven formulations based on traditional medicine, to find herbal formulations to treat inflammatory bowel disease (IBD). In the in vitro screening, nitric oxide (NO), tumor necrosis factor (TNF)-α, and interleukin (IL)-6 levels were determined in LPS-treated RAW264.7 cells and the TNF-α induced monocyte-epithelial cell adhesion assay was used for the evaluation of the anti-inflammatory activity of the compounds. Dextran sulfate sodium (DSS)-induced colitis model and 2,4,6-trinitrobenzene sulfonic acid (TNBS)-induced colitis model were used to evaluate the therapeutic effect against IBD of the samples selected from the in vitro screening. KM1608, composed of Zingiber officinale, Terminalia chebula and Aucklandia lappa, was prepared based on the screening experiments. The oral administration of KM1608 significantly attenuated the severity of colitis symptoms, such as weight loss, diarrhea, and rectal bleeding, in TNBS-induced colitis. In addition, inflammatory mediators, such as myeloperoxidase, TNF-α, and IL-6 levels decreased in the lysate of colon tissues treated with KM1608. Collectively, KM1608 ameliorated colitis through the regulation of inflammatory responses within the colon, which indicated that KM1608 had potential for the treatment of IBD.

Nanoparticle-Based Oral Drug Delivery Systems Targeting the Colon for Treatment of Ulcerative Colitis

10.1093/ibd/izy123_video1izy123.video15786481867001.

Loss of acid ceramidase in myeloid cells suppresses intestinal neutrophil recruitment

Bioactive sphingolipids are modulators of immune processes and their metabolism is often dysregulated in ulcerative colitis, a major category of inflammatory bowel disease (IBD). While multiple axes of sphingolipid metabolism have been investigated to delineate mechanisms regulating ulcerative colitis, the role of acid ceramidase (AC) in intestinal inflammation is yet to be characterized. Here we demonstrate that AC expression is elevated selectively in the inflammatory infiltrate in human and murine colitis. To probe for mechanistic insight into how AC up-regulation can impact intestinal inflammation, we investigated the selective loss of AC expression in the myeloid population. Using a model of intestinal epithelial injury, we demonstrate that myeloid AC conditional knockout mice exhibit impairment of neutrophil recruitment to the colon mucosa as a result of defective cytokine and chemokine production. Furthermore, the loss of myeloid AC protects from tumor incidence in colitis-associated cancer (CAC) and inhibits the expansion of neutrophils and granulocytic myeloid-derived suppressor cells in the tumor microenvironment. Collectively, our results demonstrate a tissue-specific role for AC in regulating neutrophilic inflammation and cytokine production. We demonstrate novel mechanisms of how granulocytes are recruited to the colon that may have therapeutic potential in intestinal inflammation, IBD, and CAC.-Espaillat, M. P., Snider, A. J., Qiu, Z., Channer, B., Coant, N., Schuchman, E. H., Kew, R. R., Sheridan, B. S., Hannun, Y. A., Obeid, L. M. Loss of acid ceramidase in myeloid cells suppresses intestinal neutrophil recruitment.