Constitutive STAT3 activation in intestinal T cells from patients with Crohn's disease

Tetrastigma hemsleyanum polysaccharide ameliorated ulcerative colitis by remodeling intestinal mucosal barrier function via regulating the SOCS1/JAK2/STAT3 pathway

Ulcerative colitis (UC) is characterized by a chronic and protracted course and often leads to a poor prognosis. Patients with this condition often experience postoperative complications, further complicating the management of their condition. Tetrastigma hemsleyanum polysaccharide (THP) has demonstrated considerable potential as a treatment for inflammatory bowel disease. However, its underlying mechanism in the treatment of UC remains unclear. This study systematically and comprehensively investigated the effects of THP on dextran sulfate-induced UC mice and illustrated its specific mechanism of action. The colon and spleen in UC mice were restored after THP treatment. The levels of key markers, such as secretory immunoglobulin A, β-defensin, and mucin-2 were increased, collagen deposition and epithelial cell apoptosis were decreased. Notably, THP administration led to increased levels of Ki67 and tight junction proteins in colon tissue and reduced colon tissue permeability. THP contributed to the restored balance of intestinal flora. Furthermore, THP downregulated the expressions of the proinflammatory cytokines interleukin (IL)-6, tumor necrosis factor (TNF)-α, and IL-17 and promoted those of the regulatory factors forkhead box protein P3. It also exerted anti-inflammatory effects by promoting suppressor of cytokine signaling (SOCS1) expression and inhibiting the Janus kinase 2 (JAK2)/signal transducer and activator of transcription 3 (STAT3) signaling pathway. Our results demonstrated that THP had an efficacy comparable to that of JAK inhibitor in treating UC. In addition, THP might play a role in UC therapy through modulation of the SOCS1/JAK2/STAT3 signaling pathway and remodeling of the intestinal mucosal barrier.

Efficacy and Safety of Upadacitinib Plus Intensive Granulocyte and Monocyte Adsorptive Apheresis as Induction for Intractable Ulcerative Colitis

Monotherapy with a selective Janus kinase (JAK) inhibitor or intensive granulocyte and monocyte adsorptive apheresis (GMA) has been limited to patients with intractable ulcerative colitis (UC). No previous reports have described the efficacy including histopathological evaluations and the safety of combination therapy with upadacitinib (UPA) plus intensive GMA (two sessions per week) for intractable UC showing resistance to conventional agents and adalimumab. This retrospective study evaluated the 10-week clinical and histopathological efficacy of induction combination therapy with UPA plus intensive GMA in patients with intractable UC. Among eight patients (moderate UC, n = 1; severe UC, n = 7) who received combination therapy with UPA plus intensive GMA, 50.0% had achieved clinical remission by 10 weeks. Percentages of patients with histological-endoscopic mucosal improvement and mucosal healing at 10 weeks were 62.5% and 12.5%, respectively. After excluding one patient who discontinued treatment by week 10 because of intolerance for UPA, mean full Mayo score, endoscopic subscore and C-reactive protein concentration at baseline were 11.43 ± 0.37, 3 ± 0 and 1.29 ± 0.70 mg/dL, respectively. Corresponding values at 10 weeks were 2.28 ± 0.77 (P < 0.03), 1.14 ± 0.34 (P < 0.03) and 0.03 ± 0.008 mg/dL (P < 0.05), respectively. Adverse events of herpes zoster, temporary increase in creatinine phosphokinase and anemia were observed in one patient each. One patient discontinued combination therapy at week 4 because of temporary taste abnormality due to UPA. Combination comprising UPA plus intensive GMA appears likely to achieve satisfactory induction of clinical remission and histopathological improvement for patients with intractable UC for whom conventional agents and anti-tumor necrosis factor-α antibody have failed.

Suppressor of cytokine signaling-3 expression and its regulation in relation to inflammation in Chronic Obstructive Pulmonary Disease

Background

The family of Suppressor of Cytokine Signaling (SOCS) acts as a controller of the duration and intensity of cytokine function by negatively regulating the JAK-STAT signaling pathway. SOCS' role in inflammatory diseases in animal models is well demonstrated. However, its role in the development of human disease is still under investigation. SOCS3 plays an important role in tumor development where its downregulation has been implicated in the pathogenesis of various solid tumors such as triple-negative breast cancer.

Aim

The aim of this work was to study (1) the expression of SOCS3 in smokers' lungs and its relation to the degree of inflammation and (2) SOCS3 regulation by microRNA (miRNA) in alveolar-macrophage (AM)-derived extracellular vesicles (EVs) in bronchoalveolar lavage (BAL).

Methods

Group A: 35 smokers' [19 with COPD (SC) and 16 without COPD (S)] and 9 nonsmokers (NS); SOCS3, TNFα in AM, and CD8+ T cells were quantified by immunohistochemistry, in lung tissue. Group B: additional 9 SC, 11 S, and 5 NS; AM-EVs expressing SOCS3 (CD14+SOCS3+) and SOCS3 suppressors miRNA-19a-3p and 221-3p in EVs were quantified by flow cytometry and PCR, in BAL.

Results

The percentage of SOCS3+ AM was higher in SC [68 (6.6-99)%] and S [48 (8-100)%] than in NS [9.6 (1.9-61)%; p = 0.002; p = 0.03] and correlated with % of TNFα+AM (r = 0.48; p = 0.0009) and CD8+ T cells (r = 0.44; p = 0.0029). In BAL, the CD14+SOCS3+ EVs/μL were increased in SC [33 (21-74)] compared to S [16 (8-37); p = 0.03] and NS [9 (7-21); p = 0.003]. Conversely, miRNA-19a-3p and miRNA-221-3p expression were increased in S when compared to SC [19 (2-53) vs. 3 (0.6-8); p = 0.03 and 3 (0.005-9.6) vs. 0.2 (0.08-0.7); p = 0.05].

Conclusions

The suppressor function of SOCS3 in COPD seems to be overridden by other factors and does not follow the animal-model paradigm. Expression of SOCS3 in BAL macrophage-derived EVs might be useful to assess the degree of inflammation and possible progression of COPD. Downregulation of SOCS3, by miRNA, in smokers without COPD might contribute to the risk of developing cancer in these patients.

Repurposing TAK875 as a novel STAT3 inhibitor for treating inflammatory bowel disease

Inflammatory bowel disease (IBD) is a chronic immune-mediated disease associated with a high recurrence rate and an elevated risk of colon cancer. In this study, we screened a bioactive compound library using a luciferase reporter assay and identified the compound TAK875 as a novel inhibitor of signal transducer and activator of transcription 3 (STAT3). Surface plasmon resonance analysis, differential scanning fluorimetry, and isothermal titration calorimetry demonstrated that TAK875 directly bound to recombinant STAT3. TAK875 suppressed the lipopolysaccharide (LPS)-induced release of nitric oxide, inducible nitric oxide synthase, and inflammatory factors in RAW264.7 cells, likely by inhibiting STAT3 phosphorylation. In addition, TAK875 inhibited the differentiation of CD4+ T cells into T-helper 17 cells, which may partially account for its anti-inflammatory effect. TAK875 also alleviated the LPS-induced accumulation of intracellular reactive oxygen species, thus displaying its antioxidant effects. Finally, we demonstrated its satisfactory anti-inflammatory effect in a dextran sulfate sodium-induced mouse model of ulcerative colitis. In conclusion, this study presented TAK875 as a novel STAT3 inhibitor and demonstrated its anti-inflammatory and antioxidant effects both in vitro and in vivo.

Cationic fructan-based pH and intestinal flora dual stimulation nanoparticle with berberine for targeted therapy of IBD

Inflammatory bowel disease (IBD) can cause intestinal microbial imbalance and aggravate intestinal inflammation. Mixed fructan is more easily fermented by colonic microorganisms and can be used as colonic drug delivery materials. Here, we constructed a mixed fructan based nanoparticle with dual targeted stimulation of pH and intestinal flora to effectively deliver berberine for the treatment of ulcerative colitis (UC). The complex of fructan based nanoparticle and berberine (BBRNPs) significantly ameliorated the inflammatory response of sodium dextran sulfate (DSS)-induced colitis in mice by inhibiting the activation of NF-κB/STAT-3 pathway and increasing tight junction protein expression in vivo. Importantly, BBRNPs improved the responsiveness of colitis microbiome and effectively regulated the relative homeostasis of harmful flora Enterobacteriaceae and Escherichia-shigolla, and beneficial flora Ruminococcaceae and Akkermansiaceae. This study provides a promising strategy for the effective treatment of UC and expands the application of branched fructan in pharmaceutics.

Natural polysaccharides protect against diet-induced obesity by improving lipid metabolism and regulating the immune system

Unhealthy dietary patterns-induced obesity and obesity-related complications pose a great threat to human health all over the world. Accumulating evidence suggests that the pathophysiology of obesity and obesity-associated metabolic disorders is closely associated with dysregulation of lipid and energy metabolism, and metabolic inflammation. In this review, three potential anti-obesity mechanisms of natural polysaccharides are introduced. Firstly, natural polysaccharides protect against diet-induced obesity directly by improving lipid and cholesterol metabolism. Since the immunity also affects lipid and energy metabolism, natural polysaccharides improve lipid and energy metabolism by regulating host immunity. Moreover, diet-induced mitochondrial dysfunction, prolonged endoplasmic reticulum stress, defective autophagy and microbial dysbiosis can disrupt lipid and/or energy metabolism in a direct and/or inflammation-induced manner. Therefore, natural polysaccharides also improve lipid and energy metabolism and suppress inflammation by alleviating mitochondrial dysfunction and endoplasmic reticulum stress, promoting autophagy and regulating gut microbiota composition. Specifically, this review comprehensively summarizes underlying anti-obesity mechanisms of natural polysaccharides and provides a theoretical basis for the development of functional foods. For the first time, this review elucidates anti-obesity mechanisms of natural polysaccharides from the perspectives of their hypolipidemic, energy-regulating and immune-regulating mechanisms.

Therapeutic Potential of a Small-Molecule STAT3 Inhibitor in a Mouse Model of Colitis

BACKGROUND AND AIMS

Inflammatory bowel disease (IBD) predisposes to colorectal cancer (CRC). In the current studies, we used the dextran sodium sulfate (DSS) murine model of colitis, which is widely used in preclinical studies, to determine the contribution of STAT3 to IBD. STAT3 has two isoforms: (STAT3 α; which has pro-inflammatory and anti-apoptotic functions, and STAT3β; which attenuates the effects of STAT3α). In the current study, we determined the contribution of STAT3 to IBD across all tissues by examining DSS-induced colitis in mice that express only STAT3α and in mice treated with TTI-101, a direct small-molecule inhibitor of both isoforms of STAT3.

METHODS

We examined mortality, weight loss, rectal bleeding, diarrhea, colon shortening, apoptosis of colonic CD4+ T-cells, and colon infiltration with IL-17-producing cells following 7-day administration of DSS (5%) to transgenic STAT3α knock-in (STAT3β-deficient; ΔβΔβ) mice and wild-type (WT) littermate cage control mice. We also examined the effect of TTI-101 on these endpoints in DSS-induced colitis in WT mice.

RESULTS

Each of the clinical manifestations of DSS-induced colitis examined was exacerbated in ΔβΔβ transgenic versus cage-control WT mice. Importantly, TTI-101 treatment of DSS-administered WT mice led to complete attenuation of each of the clinical manifestations and also led to increased apoptosis of colonic CD4+ T cells, reduced colon infiltration with IL-17-producing cells, and down-modulation of colon mRNA levels of STAT3-upregulated genes involved in inflammation, apoptosis resistance, and colorectal cancer metastases.

CONCLUSIONS

Thus, small-molecule targeting of STAT3 may be of benefit in treating IBD and preventing IBD-associated colorectal cancer.

Systematic Review and Meta-analysis of Peripheral Blood DNA Methylation Studies in Inflammatory Bowel Disease

BACKGROUND AND AIMS

Over the past decade, the DNA methylome has been increasingly studied in peripheral blood of inflammatory bowel disease [IBD] patients. However, a comprehensive summary and meta-analysis of peripheral blood leukocyte [PBL] DNA methylation studies has thus far not been conducted. Here, we systematically reviewed all available literature up to February 2022 and summarized the observations by means of meta-analysis.

METHODS

We conducted a systematic search and critical appraisal of IBD-associated DNA methylation studies in PBL using the biomarker-based cross-sectional studies [BIOCROSS] tool. Subsequently, we performed meta-analyses on the summary statistics obtained from epigenome-wide association studies [EWAS] that included patients with Crohn's disease [CD], ulcerative colitis [UC] and/or healthy controls [HC].

RESULTS

Altogether, we included 15 studies for systematic review. Critical appraisal revealed large methodological and outcome heterogeneity between studies. Summary statistics were obtained from four studies based on a cumulative 552 samples [177 CD, 132 UC and 243 HC]. Consistent differential methylation was identified for 256 differentially methylated probes [DMPs; Bonferroni-adjusted p ≤ 0.05] when comparing CD with HC and 103 when comparing UC with HC. Comparing IBD [CD + UC] with HC resulted in 224 DMPs. Importantly, several of the previously identified DMPs, such as VMP1/TMEM49/MIR21 and RPS6KA2, were consistently differentially methylated across all studies.

CONCLUSION

Methodological homogenization of IBD epigenetic studies is needed to allow for easier aggregation and independent validation. Nonetheless, we were able to confirm previous observations. Our results can serve as the basis for future IBD epigenetic biomarker research in PBL.

STAT3 regulation of Mtb-specific T cell function in active pulmonary tuberculosis patients

BACKGROUND

Tuberculosis (TB) remains one of the most serious infectious diseases in the world. Our aim was to investigate the regulatory role of STAT3 and pSTAT3 in the regulation of T cell immunophenotype and cell function.

METHODS

Twenty-five active pulmonary tuberculosis (APTB) patients, 18 latent tuberculosis infection (LTBI) patients, and 20 healthy controls (HCs) enrolled in this study. T cell phenotype and expression of STAT3 and pSTAT3 were detected by flow cytometry.

RESULTS

Compared with HCs, the expression of pSTAT3 in CD4⁺ T and CD8⁺ T cells in peripheral blood of APTB patients was increased, and the expression was higher in pleural effusion. Multifunctional T cells that simultaneously secrete IFN-γ, TNF-α and IL-17A have higher pSTAT3 expression levels. Mtb-specific T cells from APTB patients had a higher cell frequency of the STAT3⁺ pSTAT3⁺ phenotype and a reduced cell frequency of the STAT3⁺ pSTAT3^- phenotype compared with LTBI patients. Mtb-specific T cells with STAT3⁺ pSTAT3⁺ phenotype had higher expression of PD-1 and PD-L1, while cells with STAT3⁺ pSTAT3^- phenotype had higher expression of Bcl-2.

CONCLUSIONS

STAT3 and pSTAT3 in T cells of APTB patients feature in the process of anti-apoptosis and cytokine secretion. At the same time, the higher pSTAT3 may be related to the degree of cell functional exhaustion. The pSTAT3 level of T cells is related to the infection status and may indicate the clinical activity of the disease, which provides a new idea for the clinical identification and treatment of active pulmonary tuberculosis.

REMIT-UC: Real-World Effectiveness and Safety of Tofacitinib for Moderate-to-Severely Active Ulcerative Colitis: A Canadian IBD Research Consortium Multicenter National Cohort Study

INTRODUCTION

We aimed to evaluate the real-world effectiveness and safety of tofacitinib for the treatment of ulcerative colitis (UC).

METHODS

REMIT-UC is a Canadian multicenter cohort study. Standardized data collection was performed on 334 consecutive adult outpatients with UC treated with tofacitinib. The primary outcomes were achievement of clinical and endoscopic remission. Safety outcomes were reported using incidence rates (events/100 patient-years of exposure). A multivariable Cox proportional hazards model was used to evaluate predictors of loss of response after tofacitinib dose de-escalation to 5 mg twice daily (BID).

RESULTS

Clinical remission was achieved by 35.3% (106/300), 36.0% (104/289), and 35.2% (93/264) of patients at weeks 12, 24, and 52, respectively. Endoscopic remission was achieved by 18.5% (15/81), 23.0% (28/122), and 25.7% (35/136) of patients at weeks 12, 24, and 52, respectively. Incidence of serious infections, herpes zoster, and venous thromboembolism were 2.1 [0.9-4.2], 0.5 [0.1-1.9], and 1.1 [0.3-2.7], respectively. Among responders, 44.5% (109/245) lost response during follow-up, which was recaptured in 54.9% (39/71) of patients who re-escalated to 10 mg BID. Patients with a baseline Mayo endoscopic score of 3 (adjusted hazard ratio 3.60 [95% confidence interval: 1.70-7.62]) and prior biologic failure (adjusted hazard ratio 3.89 [95% confidence interval: 1.28-11.86]) were at a higher risk for losing response after dose reduction.

DISCUSSION

One-third of patients with UC treated with tofacitinib achieved clinical remission with few serious adverse events. However, half of patients lost response with de-escalation, which was only partially recaptured with increasing the maintenance dose. Those with negative prognostic factors should be counselled about the risks and benefits of continuing high doses of tofacitinib.

Qingchang Wenzhong Decoction Alleviates DSS-Induced Inflammatory Bowel Disease by Inhibiting M1 Macrophage Polarization In Vitro and In Vivo

Background

An imbalance of macrophage M1/M2 polarization significantly influences the pathogenesis of inflammatory bowel disease. Qingchang Wenzhong decoction (QCWZD) has a proven therapeutic effect on patients with inflammatory bowel disease (IBD) and can significantly inhibit the inflammatory response in mice with colitis. However, its effect on macrophages during IBD treatment remains nebulous. Aim of the Study. Explore the mechanism underlying QCWZD effects in a dextran sulfate sodium (DSS)-induced colitis mouse model in vivo and RAW264.7 cell in vitro by observing macrophage polarization dynamics.

Methods

The main active components of QCWZD were determined using high-performance liquid chromatography. Surface marker expression on M1-type macrophages was analyzed using flow cytometry and immunofluorescence. The effect on inducible nitric oxide synthase (iNOS), interleukin-6 (IL-6), and tumor necrosis factor-α (TNF-α) released by M1 type macrophages was determined using ELSA and RT-PCR. The expression of key proteins in the JAK2/STAT3 signaling pathway was analyzed using western blotting. QCWZD cytotoxicity in macrophages was measured using CCK8 and Annexin V-FITC/PI assays.

Results

The main active components of QCWZD were berberine chloride, coptisine chloride, epiberberine chloride, gallic acid, ginsenoside Rg1, ginsenoside Rb1, indigo, indirubin, notoginsenoside R1, palmatine chloride, and 6-curcumin. QCWZD markedly alleviated DSS-induced colitis in mice, as revealed by the rescued weight loss and disease activity index, attenuated the colonic shortening and mucosal injury associated with the inhibition of M1 macrophage polarization and expression of related cytokines, such as IL-6 and TNF-α, in vivo and in vitro. Furthermore, QCWZD decreased the iNOS, JAK2, and STAT3 levels in vivo and in vitro, regulating the JAK2/STAT3 signaling pathway.

Conclusion

QCWZD administration improves intestinal inflammation by inhibiting M1 macrophage polarization. The JAK2/STAT3 signaling pathway may mediate the effects of QCWZD on M1 macrophage polarization in colitis treatment. This study presents a novel macrophage-mediated therapeutic strategy for the treatment of IBD.

Aronia melanocarpa (Michx.) Elliott. attenuates dextran sulfate sodium-induced Inflammatory Bowel Disease via regulation of inflammation-related signaling pathways and modulation of the gut microbiota

ETHNOPHARMACOLOGICAL RELEVANCE

Aronia melanocarpa (Michx.) Elliott. Is one of the most functional berries usually used in the preparation of juice and jams, but it has revealed its ethnopharmacological properties due to their richness in biologically active molecules with pharmaceutical and physiological effects.

AIMS OF THE STUDY

The aim of this study was to assess the antioxidant and anti-inflammatory effects of Aronia melanocarpa ethanol-extract as well as the possible mechanisms of action involved and the modulation of gut microbiota in Dextran Sulfate Sodium (DSS)-induced Inflammatory bowel disease in mice.

MATERIALS AND METHODS

Inflammatory bowel disease (IBD) were induced by DSS in drinking water for 7 days to evaluate the properties of A. melanocarpa ethanol-extract (AME) on the intestinal microflora. AME was administered orally to DSS-induced IBD mice for 21 days. Clinical, inflammatory, histopathological parameters, and different mRNA and proteins involved in its possible mechanism of action were determined as well as gut microbiota analysis via 16S high throughput sequencing.

RESULTS

AME improved clinical symptoms and regulated histopathological parameters, pro- and anti-inflammatory cytokines and oxidative stress factors as well as mRNA and protein expressions of transcription factors involved in maintaining the intestinal barrier integrity. In addition, AME also reversed the DSS-induced intestinal dysbiosis effects promoting the production of cecal short chain fatty acids linked to signaling pathways inhibiting IBD.

CONCLUSION

AME improved intestinal lesions induced by DSS suggesting that A. melanocarpa berries could have significant therapeutic potential against IBD due to their antioxidant and anti-inflammatory capacities as well as their ability to restore the gut microbiota balance.

New insights into IL-6 family cytokines in metabolism, hepatology and gastroenterology

IL-6 family cytokines are defined by the common use of the signal-transducing receptor chain glycoprotein 130 (gp130). Increasing evidence indicates that these cytokines are essential in the regulation of metabolic homeostasis as well as in the pathophysiology of multiple gastrointestinal and liver disorders, thus making them attractive therapeutic targets. Over the past few years, therapies modulating gp130 signalling have grown exponentially in several clinical settings including obesity, cancer and inflammatory bowel disease. A newly engineered gp130 cytokine, IC7Fc, has shown promising preclinical results for the treatment of type 2 diabetes, obesity and liver steatosis. Moreover, drugs that modulate gp130 signalling have shown promise in refractory inflammatory bowel disease in clinical trials. A deeper understanding of the main roles of the IL-6 family of cytokines during homeostatic and pathological conditions, their signalling pathways, sources of production and target cells will be crucial to the development of improved treatments. Here, we review the current state of the role of these cytokines in hepatology and gastroenterology and discuss the progress achieved in translating therapeutics targeting gp130 signalling into clinical practice.

Inhibition of miR-1298-5p attenuates sepsis lung injury by targeting SOCS6

Sepsis is one of the leading causes of morbidity and mortality and a major cause of acute lung injury (ALI). carried by exosomes play a role in a variety of diseases. However,there are not many studies of exosomal miRNAs in sepsis and sepsis lung injury.miR-1298-5p and suppressor of cytokine signaling 6 (SOCS6) were silenced or overexpressed in human bronchial epithelial cells (BEAS-2B). PKH-67 Dye was used to trace exosome endocytosis. Cell permeability was evaluated by measuring trans-epithelial electrical resistance (TEER) and FITC dextran flux. ELISA kits were used for cytokine detection. Quantitative RT-PCR and western blots were used to evaluate gene expression. miR-1298-5p was elevated in exosomes from patients with sepsis lung injury (Sepsis_exo). Treatment of BEAS-2B cells using Sepsis_exo significantly inhibited cell proliferation, and induced cell permeability and inflammatory response. miR-1298-5p directly targeted SOCS6. Overexpressing SOCS6 reversed miR-1298-5p-induced cell permeability and inflammatory response. Inhibition of STAT3 blocked SOCS6-silencing caused significant increase of cell permeability and inflammation. Exosomes isolated from patients of sepsis lung injury increased cell permeability and inflammatory response in BEAS-2B cells through exosomal miR-1298-5p which targeted SOCS6 via STAT3 pathway. The findings highlight the importance of miR-1298-5p/SOCS6/STAT3 axis in sepsis lung injury and provide new insights into therapeutic strategies for sepsis lung injury.

Upregulation of signal transducer and activator of transcription 3 in dogs with chronic inflammatory enteropathies

Background

In inflammatory bowel disease (IBD) in humans, phosphorylated signal transducer and activator of transcription 3 (pSTAT3) is upregulated in mucosal epithelial cells and correlates with clinical severity.

Hypothesis/Objective

To investigate the expression pattern of pSTAT3 in the mucosa of dogs with chronic inflammatory enteropathy (CIE) and explore correlations between its expression and clinical and histopathological severity scoring.

Animals

Twenty‐eight canine CIE patients grouped into food‐responsive enteropathy (FRE;  9), steroid‐responsive enteropathy (SRE;  10), and protein‐losing enteropathy (PLE;  9). Ten healthy beagle dogs served as controls (CO).

Methods

Retrospective case control study. Immunohistochemistry was used to detect pSTAT3 in canine duodenal mucosa samples.

Results

Compared to CO, SRE (P < .001) and PLE (P < .001) dogs had significantly higher pSTAT3 expression in the villus epithelium. The SRE group had a significantly higher expression in the villus lamina propria (VLP) compared to controls (P = .009). In the crypt epithelium (CE), all CIE dogs had significantly higher pSTAT3 expression (FRE, P = .002; SRE, P = .003; PLE, P < .001) compared to CO. In the lamina propria crypt region (CLP), dogs with FRE (P = .04) and SRE (P = .03) had significantly upregulated pSTAT3 compared to controls. A positive correlation was found between canine chronic enteropathy clinical activity index (CCECAI) scoring and pSTAT3 expression for both epithelial (rho = .541; P < .001) and crypt regions (rho = .32; P = .02).

Conclusions and Clinical Importance

pSTAT3 is upregulated in CIE in dogs, correlates with clinical severity, and may be helpful as a clinical marker in dogs with CIE.

Shaoyao Decoction Inhibits Inflammation and Improves Intestinal Barrier Function in Mice With Dextran Sulfate Sodium-Induced Colitis

Shaoyao decoction (SYD), a classical traditional Chinese medicine formula, is effective for the treatment of inflammatory bowel disease (IBD). This study was designed to investigate the therapeutic effects of SYD on IBD and possible mechanisms. Dextran sulfate sodium (DSS, 3.5%) was used to induce colitis in C57BL/6 mice. Disease phenotypes were investigated based on disease activity index (DAI), colon length, and microscopic and macroscopic scores. Additionally, the presence of proinflammatory cytokines, immune cell infiltrates, intestinal cell proliferation, apoptosis, epithelial permeability, signal transducer and activator of transcription 3 (STAT3), and nuclear factor-κB (NF-κB) signaling, as well as the intestinal mucosal barrier function, were investigated. The administration of SYD significantly ameliorated the clinical signs, suppressed the levels of proinflammatory cytokines, and reduced immune cell infiltrates into colonic tissues of DSS-induced colitis model mice. SYD also significantly reduced the DSS-induced activation of STAT3 and NF-κB signaling. Furthermore, SYD promoted epithelial integrity by regulating epithelial cell apoptosis and epithelial permeability. Finally, we demonstrated that SYD protected the intestinal barrier function by significantly regulating the mucus layer genes Muc1, Muc2, Muc4, and Tff3, as well as the epithelial barrier genes Z O -1 and Occludin. Our results indicate that SYD has a protective effect on DSS-induced colitis, which is attributable to its anti-inflammatory activity and intestinal barrier function-enhancing effects. These results provide valuable insights into the pharmacological actions of SYD for the treatment of IBD.

Posttranslational modifications as therapeutic targets for intestinal disorders

A variety of biological processes are regulated by posttranslational modifications. Posttranslational modifications including phosphorylation, ubiquitination, glycosylation, and proteolytic cleavage, control diverse physiological functions in the gastrointestinal tract. Therefore, a better understanding of their implications in intestinal diseases, including inflammatory bowel disease, irritable bowel syndrome, celiac disease, and colorectal cancer would provide a basis for the identification of novel biomarkers as well as attractive therapeutic targets. Posttranslational modifications can be common denominators, as well as distinct biomarkers, characterizing pathological differences of various intestinal diseases. This review provides experimental evidence that identifies changes in posttranslational modifications from patient samples, primary cells, or cell lines in intestinal disorders, and a summary of carefully selected information on the use of pharmacological modulators of protein modifications as therapeutic options.

Sphingosine-1-phosphate signal transducer and activator of transcription 3 signaling pathway contributes to baicalein-mediated inhibition of dextran sulfate sodium-induced experimental colitis in mice

Background:

Baicalein has been shown to have anti-inflammatory and anti-tumor activities. However, the mechanisms underlying its anti-inflammatory effect on colitis remain unclear.

Methods:

A dextran sodium sulfate (DSS)-induced model of acute colitis was established in BALB/c mice (6–8 weeks old, weighing 18–22 g). Six groups of mice received: (1) water for 10 days (control), n = 6; (2) DSS 4% solution in the drinking water for 7 days, followed by normal water for 3 days, n = 7; (3), (4), and (5) as for group 2 plus baicalein (10, 20, 40 mg/kg) administered once daily starting on day 1, n = 6; and (6) as for (2) plus 5-aminosalicylic acid (50 mg/kg) administered once daily starting on day 1, n = 6. Body weights, stool consistency, and hematochezia were recorded, and the severity of colitis was evaluated using a disease activity index. On day 11, the mice were euthanized, and organs and blood were collected for analysis. Serum inflammatory factors were detected by enzyme-linked immunosorbent assay; CD11b-positive cells were analyzed by immunofluorescence microscopy; expression of retinoic-acid-receptor-related orphan nuclear receptor gamma, sphingosine kinase 1 (SPHK1), and phosphorylated signal transducer and activator of transcription 3 (p-STAT3) was detected by immunohistochemistry; and expression of nucleotide-binding oligomerization domain 2 (NOD2), SPHK1, sphingosine 1-phosphate receptor 1 (S1PR1), total STAT3, and p-STAT3 were detected by western blotting analysis. Inter-group differences were compared using Student's t test.

Results:

Baicalein treatment dose-dependently reduced DSS-induced weight loss (P < 0.01 or P < 0.05), splenomegaly (P < 0.01), and colonic damage, as reflected by amelioration of diarrhea, rectal bleeding, and colonic ulceration, congestion, edema (shown as colon length, P < 0.05 or P < 0.01), and inflammatory cell infiltration. Baicalein also significantly decreased the levels of inflammatory mediators in the serum (P < 0.01) and colon, and significantly inhibited expression of NOD2 SPHK1, S1PR1, and p-STAT3 in the colon (P < 0.05).

Conclusions:

Baicalein treatment ameliorated colitis in mice by inhibiting S1P-STAT3 signaling, suggesting that this flavonoid might be beneficial in the treatment of colitis.

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.

STAT3 Differentially Regulates TLR4-Mediated Inflammatory Responses in Early or Late Phases

Toll-like receptor 4 (TLR4) signaling is an important therapeutic target to manage lipopolysaccharide (LPS)-induced inflammation. The transcription factor signal transducer and activator of transcription 3 (STAT3) has been identified as an important regulator of various immune-related diseases and has generated interest as a therapeutic target. Here, we investigated the time-dependent roles of STAT3 in LPS-stimulated RAW264.7 macrophages. STAT3 inhibition induced expression of the pro-inflammatory genes iNOS and COX-2 at early time points. STAT3 depletion resulted in regulation of nuclear translocation of nuclear factor (NF)-κB subunits p50 and p65 and IκBα/Akt/PI3K signaling. Moreover, we found that one Src family kinase, Lyn kinase, was phosphorylated in STAT3 knockout macrophages. In addition to using pharmacological inhibition of NF-κB, we found out that STAT3KO activation of NF-κB subunit p50 and p65 and expression of iNOS was significantly inhibited; furthermore, Akt tyrosine kinase inhibitors also inhibited iNOS and COX-2 gene expression during early time points of LPS stimulation, demonstrating an NF-κB- Akt-dependent mechanism. On the other hand, iNOS expression was downregulated after prolonged treatment with LPS. Activation of NF-κB signaling was also suppressed, and consequently, nitric oxide (NO) production and cell invasion were repressed. Overall, our data indicate that STAT3 differentially regulates early- and late-phase TLR4-mediated inflammatory responses.

JAK selectivity: more precision less troubles

INTRODUCTION

Janus kinases inhibitors (JAKi) are new small molecules recently introduced in the armamentarium of treatments for Inflammatory Bowel Disease (IBD). Janus Kinases (JAK) are tyrosine kinases that act by linkage with different intracellular receptors, regulating cytokines gene transcription implicated in the inflammatory burden seen in IBD patients.

AREAS COVERED

A comprehensive literature search was performed to retrieve studies on JAKi and IBD to discuss the latest developments and how the selectivity of these drugs is changing the natural course of IBD.

EXPERT OPINION

Available data on efficacy and safety of JAKi in IBD are highly encouraging and because of their selectivity, these drugs might become among the foremost options in the treatment algorithm.

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

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

T-Cell Large Granular Lymphocyte Leukemia in a Patient With Rheumatoid Arthritis

Large granular lymphocyte leukemia (LGL) is a clonal, lymphoproliferative disorder with an indolent disease course. T-cell LGL (T-LGL) is the most common type of LGL driven from T-cell lineage (85%). The coexistence of T-LGL with several types of autoimmune disorders, mostly rheumatoid arthritis (RA), has been reported. Felty’s syndrome (FS) is defined by splenomegaly, low neutrophil count, and destructive arthritis and is usually seen in <1% of patients with RA. About 30% to 40% of patients with FS have been reported to have an expansion of large granulated lymphocytes in the circulation. FS and T-LGL are similar in terms of clinical manifestations, response to immunosuppressive therapy, their smoldering course, and immunogenetic findings, proposing FS and T-LGL with RA might be different aspects of a single disease spectrum. In this article, we present a case with long-standing RA who had never been on DMARD (Disease Modifying Anti-Rheumatic Drugs) treatment found to have constitutional symptoms, neutropenia, and splenomegaly, and the patient was diagnosed with T-LGL.

Anti-inflammatory properties of uvaol on DSS-induced colitis and LPS-stimulated macrophages

Background

Apocynum venetum leaves are used as a kind of phytomedicine and the main ingredient in some traditional Chinese medicine products for the relief of colitis. To understand the bioactive constituents of A. venetum L., we did a phytochemistry study and investigated anti-Inflammatory effects of compounds and explored the underlying mechanisms.

Methods

We isolated compounds from ethanol extract of A. venetum L. leaf and detected the most effective compound by NO inhibition assay. We investigated anti-Inflammatory effects on dextran sulfate sodium (DSS)-induced colitis mice and lipopolysaccharide (LPS)-stimulated RAW264.7 cells. The disease activity index was determined by scores of body weight loss, diarrhea and rectal bleeding; histological damage was analyzed by H&E staining; macrophages change in the colon were analyzed by immunohistochemistry (IHC); myeloperoxidase activity was measured by myeloperoxidase assay kits; levels of proinflammatory cytokines were determined by qPCR and ELISA; protein production such as COX-2, iNOS, STAT3 and ERK1/2 were determined by western blotting.

Results

We isolated uvaol from ethanol extract of A. venetum L. leaf and found uvaol has excellent potential of inhibiting NO production. We further found uvaol could attenuate disease activity index (DAI), colon shortening, colon injury, and colonic myeloperoxidase activity in DSS-induced colitis mice. Moreover, uvaol significantly reduces mRNA expression and production of pro-inflammatory cytokines (TNF-α, IL-6, IL-1β, and MCP-1) and infiltration of macrophages in colonic tissues of colitis mice. Studies on LPS challenged murine macrophage RAW246.7 cells also revealed that uvaol reduces mRNA expression and production of pro-inflammatory cytokines and mediators. Mechanically, uvaol inhibits the pro-inflammatory ERK/STAT3 axis in both inflamed colonic tissues and macrophages.

Conclusions

A. venetum leaf contains uvaol and uvaol has potent anti-inflammatory effects on DSS-induced experimental colitis and LPS-stimulated RAW264.7 macrophage cells. These results suggest uvaol is a prospective anti-inflammatory agent for colonic inflammation.

Transcriptional Regulators of T Helper 17 Cell Differentiation in Health and Autoimmune Diseases

T helper (Th) 17 cells are a subtype of CD4 T lymphocytes characterized by the expression of retinoic acid-receptor (RAR)-related orphan receptor (ROR)γt transcription factor, encoded by gene Rorc. These cells are implicated in the pathology of autoimmune inflammatory disorders as well as in the clearance of extracellular infections. The main function of Th17 cells is the production of cytokine called interleukin (IL)-17A. This review highlights recent advances in mechanisms regulating transcription of IL-17A. In particular, we described the lineage defining transcription factor RORγt and other factors that regulate transcription of Il17a or Rorc by interacting with RORγt or by binding their specific DNA regions, which may positively or negatively influence their expression. Moreover, we reported the eventual involvement of those factors in Th17-related diseases, such as multiple sclerosis, rheumatoid arthritis, psoriasis, and Crohn's disease, characterized by an exaggerated Th17 response. Finally, we discussed the potential new therapeutic approaches for Th17-related diseases targeting these transcription factors. The wide knowledge of transcriptional regulators of Th17 cells is crucial for the better understanding of the pathogenic role of these cells and for development of therapeutic strategies aimed at fighting Th17-related diseases.

Combination Therapy With Tofacitinib Plus Intensive Granulocyte and Monocyte Adsorptive Apheresis as Induction Therapy for Refractory Ulcerative Colitis

Background

The use of monotherapy with intensive granulocyte and monocyte adsorptive apheresis (GMA) or a Janus kinase (JAK) inhibitor has been limited to patients with refractory ulcerative colitis (UC). The efficacy and safety of combination therapy with tofacitinib (TOF) plus intensive GMA (two sessions per week) for refractory UC have not been evaluated.

Methods

This retrospective study evaluated the 10-week efficacy of combination therapy with TOF plus intensive GMA in patients with refractory UC.

Results

Of seven patients who received a combination therapy with TOF plus intensive GMA, 71.4% achieved clinical remission at 10 weeks. The percentages of patients with mucosal healing and complete mucosal healing at 10 weeks were 100% and 42.9%, respectively. The mean full Mayo score and endoscopic subscore at baseline were 8.71 ± 0.80 and 2.4 ± 0.2, respectively, and the corresponding values at 10 weeks were 1.57 ± 0.48 and 0.6 ± 0.2 (P < 0.01), respectively. Adverse events of an orolabial herpes and temporary increase in creatinine phosphokinase (CK) and triglyceride were observed in three patients.

Conclusions

Based on these outcomes, combination therapy with TOF plus intensive GMA was well tolerated and may be useful for induction of clinical remission in patients with refractory UC.

Systems biology analysis identifies molecular determinants of chemotherapy-induced diarrhoea

Chemotherapy-induced diarrhoea (CID) is a common dose-limiting adverse event in patients with cancer. Here, we hypothesise that chemotherapy evokes apoptosis in normal gut epithelium, contributes to CID and that patients with increased risk of CID can be identified using a systems model of BCL-2 protein interactions (DR_MOMP) that calculates the sensitivity of cells to undergo apoptosis. Normal adjacent gut epithelium tissue was collected during resection surgery from a cohort of 35 patients with stage II-III colorectal cancer (CRC) who were subsequently treated with capecitabine, XELOX or FOLFOX. Clinical follow-up, type and grade of adverse events during adjuvant chemotherapy were recorded. The level of five BCL-2 proteins required for the calculation of the DR_MOMP score was quantified together with 62 additional signalling proteins related to apoptotic pathways. Odds ratios for the occurrence of diarrhoea were determined using multinomial logistic regression (MLR). Patients treated with capecitabine who had a DR_MOMP score equal or higher than the mean had a significantly lower frequency of diarrhoea significantly compared to patients below the mean. High DR_MOMP scores indicate high apoptosis resistance. No statistical difference was observed in patients treated with XELOX or FOLFOX. Using MLR, we found that levels of apoptosis-related proteins caspase-8, p53 and XIAP statistically interacted with the DR_MOMP stress dose. Markers of MAPK signalling were prognostic for diarrhoea independently of DR_MOMP. In conclusion, apoptosis sensitivity and MAPK signalling status of the adjacent normal gut epithelium of chemotherapy-naïve patients represent promising biomarkers to identify patients with CRC with increased risk of CID.

Innovations in Oral Therapies for Inflammatory Bowel Disease

Prior to the biologic era, the medical management of patients with inflammatory bowel disease (IBD) was dominated by the use of aminosalicylates, corticosteroids, and immunosuppressants. In the past two decades, the advent of biologic agents that target specific components of the immune response has greatly improved the care of patients with Crohn's disease and ulcerative colitis (UC). However, not all patients respond or maintain response to biologic therapy and some patients develop adverse events that necessitate treatment discontinuation. Furthermore, sensitization with formation of anti-drug antibodies is an inherent limitation to administration of monoclonal antibodies. This circumstance has generated renewed interest in the development of novel oral small-molecule drugs (SMDs) that are effective and well tolerated. Several classes of SMDs are currently progressing through the pipeline and offer the promise of oral delivery and high potency. In this review, we summarize different mechanisms of oral drug delivery to the gastrointestinal tract, highlight key findings from phase II and III randomized trials of novel oral SMDs, and discuss how oral SMDs are likely to be integrated into future IBD treatment paradigms. The most advanced development programs currently involve evaluation of compounds blocking Janus kinase (JAK) receptors or modulating sphingosine-1-phosphate (S1P) receptors. Tofacitinib, an oral JAK inhibitor, was recently approved for the treatment of moderate-to-severe UC. Several more selective JAK-1 inhibitors, including filgotinib and upadacitinib, have also shown positive results in phase II studies and are currently enrolling in phase III development programs. Similarly, ozanimod, an S1P1 and S1P5 receptor agonist, has shown early favorable results and is enrolling in phase III trials. As these and other novel oral SMDs come to market, several questions will need to be answered. The cost effectiveness, comparative treatment efficacy, predictors of response, and relative safety of oral SMDs compared to existing therapies will need to be evaluated. Given the modest efficacy rates observed with both biologic therapies and novel SMDs to date, the potential for combination therapy based on a non-sensitizing oral option is promising and may be facilitated by development of organ-specific therapies with pharmacodynamic activity restricted to the gut to minimize systemic toxicity.

Blockade of STAT3 Causes Severe In Vitro and In Vivo Maturation Defects in Intestinal Organoids Derived from Human Embryonic Stem Cells

Human intestinal organoids (hIOs), which resemble the human intestine structurally and physiologically, have emerged as a new modality for the study of the molecular and cellular biology of the intestine in vitro. We recently developed an in vitro maturation technique for generating functional hIOs from human pluripotent stem cells (hPSCs). Here, we investigated the function of STAT3 for inducing in vitro maturation of hIOs. This was accompanied by the tyrosine phosphorylation of STAT3, whereas treatment with pharmacological inhibitors of STAT3 suppressed the phosphorylation of STAT3 and the expression of intestinal maturation markers. We generated and characterized STAT3 knockout (KO) human embryonic stem cell (hESC) lines using CRISPR/Cas9-mediated gene editing. We found that STAT3 KO does not affect the differentiation of hESCs into hIOs but rather affects the in vitro maturation of hIOs. STAT3 KO hIOs displayed immature morphologies with decreased size and reduced budding in hIOs even after in vitro maturation. STAT3 KO hIOs showed markedly different profiles from hIOs matured in vitro and human small intestine. Additionally, STAT3 KO hIOs failed to maintain upon in vivo transplantation. This study reveals a core signaling pathway consisting of STAT3 controlling the in vitro maturation of hIOs derived from hPSCs.

Pharmacology, efficacy and safety of JAK inhibitors in Crohn's disease

Orally bioavailable inhibitors of the tyrosine kinases (TYKs), also referred to as Janus kinases (JAKs), are being evaluated for the treatment of patients with Crohn's disease (CD), ulcerative colitis (UC), and other chronic inflammatory disorders. To date, three JAK inhibitors have been tested in patients with moderate-to-severe CD: tofacitinib (pan-JAK inhibitor), filgotinib (JAK1 inhibitor) and upadacitinib (JAK1 inhibitor). Clinical development of tofacitinib was discontinued in CD because the primary endpoint of clinical remission in the phase II induction and maintenance trials was not met, although outcomes may have been influenced by trial design flaws and a high placebo rate was noted. In contrast, filgotinib did meet its primary endpoint of clinical remission at week 10 in the phase II FITZROY trial, in addition to several other clinically important secondary outcomes, spurring a subsequent larger phase III trial. Following promising results for upadacitinib in its phase II trial, larger phase III trials were also initiated to corroborate the efficacy results. Although JAK inhibitors appear to have an acceptable safety profile, higher rates of infections compared to placebo were noted. Overall, JAK inhibitors constitute a new promising class of drugs, given the efficacy signals observed in pivotal clinical trials in several chronic inflammatory diseases. Here we review the existing evidence on the pharmacology, safety and efficacy of JAK-STAT inhibitors that are currently under investigation for the treatment of patients with CD.

Constitutive STAT3 phosphorylation and IL-6/IL-10 co-expression are associated with impaired T-cell function in tuberculosis patients

T-cells critically contribute to protection against Mycobacterium tuberculosis infection, and impaired T-cell responses can lead to disease progression. Pro-inflammatory and immunosuppressive cytokines affect T-cells, and fine-tuned regulation of cytokine signaling via the Jak/STAT signaling pathways is crucial for appropriate T-cell function. Constitutive STAT3 phosphorylation as a consequence of aberrant cytokine signaling has been described to occur in pathognomonic T-cell responses in inflammatory and autoimmune diseases. We characterized blood samples from tuberculosis patients (n=28) and healthy contacts (n=28) from Ghana for M. tuberculosis-specific T-cell responses, constitutive cytokine production, and SOCS3 and pSTAT3 expression. Lentiviral modulation of primary CD4+ T-cells was performed to determine the effects of SOCS3 on T-cell functions. T-cells from tuberculosis patients expressed higher levels of IL-10 and IL-6 and lower levels of T helper type (TH)17 cytokines after M. tuberculosis-specific stimulation compared to healthy contacts. In addition, tuberculosis patients had higher IL-10 and IL-6 levels in the supernatants of non-stimulated immune cells and plasma samples compared to healthy contacts. Notably, aberrant cytokine expression was accompanied by high constitutive pSTAT3 levels and SOCS3 expression in T-cells. Multivariate analysis identified an IL-6/IL-10 co-expression-based principal component in tuberculosis patients that correlated with high pSTAT3 levels. SOCS3 contributed to a regulatory component, and tuberculosis patients with high SOCS3 expression showed decreased TH1 cytokine expression and impaired IL-2-induced STAT5 phosphorylation. SOCS3 over-expression in primary CD4+ T-cells confirmed the SOCS3 inhibitory function on IL-2-induced STAT5 phosphorylation. We conclude that constitutive pSTAT3 and high SOCS3 expression are influential factors that indicate impaired T-cell functions in tuberculosis patients.

Dysbiosis of the Gut Microbiota on the Inflammatory Background due to Lack of Suppressor of Cytokine Signalling-1 in Mice

Background

Both environmental and genetic factors have been implicated in the induction of autoimmune disease. Therefore, it is important to understand the pathophysiological significance of the gut microbiota and host genetic background that contribute to an autoimmune disease such as inflammatory bowel disease (IBD). We have previously reported that mice deficient for suppressor of cytokine signaling-1 (SOCS1), in which SOCS1 expression was restored in T and B cells on an SOCS1^-/- background (SOCS1^-/-Tg mice), developed systemic autoimmune diseases accompanied by spontaneous colitis.

Methods

To investigate whether the proinflammatory genetic background affects the gut microbiota, we used SOCS1^-/-Tg mice as a model of spontaneous chronic colitis. Fecal samples were collected from SOCS1^-/-Tg mice and SOCS1^+/+Tg (control) mice at 1 and 6 months of age, and the fecal bacterial 16S ribosomal RNA genes were sequenced using the Illumina MiSeq platform.

Results

Gut microbial diversity was significantly reduced and the intestinal bacterial community composition changed in SOCS1^-/-Tg mice in comparison with the control mice. Interestingly, the population of Prevotella species, which is known to be elevated in ulcerative colitis and colorectal cancer patients, was significantly increased in SOCS1^-/-Tg mice regardless of age.

Conclusion

Taken together, these results suggest that the proinflammatory genetic background owing to SOCS1 deficiency causes dysbiosis of the gut microbiota, which in turn generates a procolitogenic environment.

Anti-Colitic Effects of Ethanol Extract of Persea americana Mill. through Suppression of Pro-Inflammatory Mediators via NF-κB/STAT3 Inactivation in Dextran Sulfate Sodium-Induced Colitis Mice

Persea americana Mill, cv. Hass, also known as avocado, has been reported to possess hypolipidemic, anti-diabetic, anti-oxidant, cardioprotective, and photoprotective potencies. However, few studies have reported its anti-colitic effects. In this study, we investigated anti-colitic effects of ethanol extract of P. americana (EEP) in dextran sulfate sodium (DSS)-induced colitic mice and the involved molecular mechanisms. EEP effectively improved clinical signs and histological characteristics of DSS-induced colitis mice. In DSS-exposed colonic tissues, EEP reduced expression levels of inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), and pro-inflammatory cytokines such as interleukin (IL)-6, IL-1β, and tumor necrosis factor (TNF)-α. Moreover, EEP suppressed DSS-induced activation of nuclear factor-kappa B (NF-κB) and signal transducer and activator of transcription 3 (STAT3). Consistent with in vivo results, EEP also suppressed protein and mRNA expression levels of iNOS, COX-2, and pro-inflammatory cytokines via NF-κB and STAT3 inactivation in LPS-induced RAW 264.7 macrophages. Taken together, our data indicate that ethanol extract of avocado may be used as a promising therapeutic against inflammatory bowel diseases by suppressing the NF-κB and STAT3 signaling pathway.

Contribution of STAT3 to Inflammatory and Fibrotic Diseases and Prospects for its Targeting for Treatment

Signal transducer and activator of transcription (STAT) 3 plays a central role in the host response to injury. It is activated rapidly within cells by many cytokines, most notably those in the IL-6 family, leading to pro-proliferative and pro-survival programs that assist the host in regaining homeostasis. With persistent activation, however, chronic inflammation and fibrosis ensue, leading to a number of debilitating diseases. This review summarizes advances in our understanding of the role of STAT3 and its targeting in diseases marked by chronic inflammation and/or fibrosis with a focus on those with the largest unmet medical need.

Polysaccharides From Chrysanthemum morifolium Ramat Ameliorate Colitis Rats via Regulation of the Metabolic Profiling and NF-κ B/TLR4 and IL-6/JAK2/STAT3 Signaling Pathways

Studies have indicated that Chrysanthemum polysaccharides (CP) could prominently ameliorate colitis rats, but its possible mechanism remains unclear. In this study, the underlying mechanism of CP was explored by the metabolic profiling analysis and correlated signaling pathways. TNBS/ethanol induced colitis was used to investigate the intervention efficacy following oral administration of CP. The levels of cytokines such as TNF-α, IL-6, IFN-γ and IL-1β, and the activities of SOD, MPO, and MDA were determined. We also performed western-blot for p65, TLR4, p-JAK2, and STAT3 protein expression in the colon tissue to probe their mechanisms of correlated signaling pathways. What’s more, the metabolic changes in plasma and urine from colitis rats were investigated based on UPLC-Q-TOF/MS combined with Metabolynx^TM software. The potential biomarkers and metabolic pathways were also tentatively confirmed. The metabolic profiles of plasma and urine were clearly improved in model rats after oral administration of CP. Thirty-two (17 in serum and 15 in urine) potential biomarkers were identified. The endogenous metabolites were mainly involved in linoleic acid, retinol, arachidonic acid, glycerophospholipid and primary bile acid metabolism in plasma, and nicotinate and nicotinamide, ascorbate and aldarate, histidine and β-alanine metabolism in urine. After polysaccharides intervention, these markers turned back to normal level at some extent. Meanwhile, the elevated expression levels of pp65, TLR4, p-STAT3, and p-JAK2 were significantly decreased after treatment. Results suggested that CP would be a potential prebiotics for alleviation of TNBS-induced colitis. The study paved the way for the further exploration of the pathogenesis, early diagnosis and curative drug development of the colitis.

Obstructive Lymphangitis Precedes Colitis in Murine Norovirus-Infected Stat1-Deficient Mice

Murine norovirus (MNV) is an RNA virus that can prove lethal in mice with impaired innate immunity. We found that MNV-4 infection of Stat1-/- mice was not lethal, but produced a 100% penetrant, previously undescribed lymphatic phenotype characterized by chronic-active lymphangitis with hepatitis, splenitis, and chronic cecal and colonic inflammation. Lesion pathogenesis progressed from early ileal enteritis and regional dilated lymphatics to lymphangitis, granulomatous changes in the liver and spleen, and, ultimately, typhlocolitis. Lesion development was neither affected by antibiotics nor reproduced by infection with another enteric RNA virus, rotavirus. MNV-4 infection in Stat1-/- mice decreased expression of vascular endothelial growth factor (Vegf) receptor 3, Vegf-c, and Vegf-d and increased interferon (Ifn)-γ, tumor necrosis factor-α, and inducible nitric oxide synthase. However, anti-IFN-γ and anti-tumor necrosis factor-α antibody treatment did not attenuate the histologic lesions. Studies in Ifnαβγr-/- mice suggested that canonical signaling via interferon receptors did not cause MNV-4-induced disease. Infected Stat1-/- mice had increased STAT3 phosphorylation and expressed many STAT3-regulated genes, consistent with our findings of increased myeloid cell subsets and serum granulocyte colony-stimulating factor, which are also associated with increased STAT3 activity. In conclusion, in Stat1-/- mice, MNV-4 induces lymphatic lesions similar to those seen in Crohn disease as well as hepatitis, splenitis, and typhlocolitis. MNV-4-infected Stat1-/- mice may be a useful model to study mechanistic associations between viral infections, lymphatic dysfunction, and intestinal inflammation in a genetically susceptible host.

Effector T Helper Cell Subsets in Inflammatory Bowel Diseases

The gastrointestinal tract is a site of high immune challenge, as it must maintain a delicate balance between tolerating luminal contents and generating an immune response toward pathogens. CD4⁺ T cells are key in mediating the host protective and homeostatic responses. Yet, CD4⁺ T cells are also known to be the main drivers of inflammatory bowel disease (IBD) when this balance is perturbed. Many subsets of CD4⁺ T cells have been identified as players in perpetuating chronic intestinal inflammation. Over the last few decades, understanding of how each subset of Th cells plays a role has dramatically increased. Simultaneously, this has allowed development of therapeutic innovation targeting specific molecules rather than broad immunosuppressive agents. Here, we review the emerging evidence of how each subset functions in promoting and sustaining the chronic inflammation that characterizes IBD.

Pien Tze Huang ameliorates DSS‑induced colonic inflammation in a mouse colitis model through inhibition of the IL‑6/STAT3 pathway

Interleukin‑6 (IL‑6)/signal transducer and activator of transcription 3 (STAT3) pathway plays essential roles in the development of inflammatory diseases including ulcerative colitis (UC). Therefore, suppression of IL‑6/STAT3 signaling provides a promising therapeutic strategy in UC. Pien Tze Huang (PZH), a well‑known traditional Chinese formula, has been used in China and Southeast Asia for centuries as a folk remedy for various inflammatory diseases. However, the molecular mechanisms of its anti‑inflammatory effects remain to be elucidated. In the present study, we generated a mouse colitis model by using dextran sulfate sodium (DSS) and evaluated the therapeutic efficacy of PZH against UC by observing the clinical manifestations. We found that PZH obviously alleviated DSS‑induced colitis symptoms, including body weight loss, rectal bleeding and stool consistency. In addition, administration of PZH profoundly prevented DSS‑induced colon shortening, and ameliorated colonic histopathological changes such as mucosal ulceration, infiltration of inflammatory cells, crypt distortion and hyperplastic epithelium. Moreover, PZH markedly inhibited the serum level of the inflammatory biomarker serum amylase A (SAA) in UC mice. Furthermore, PZH treatment significantly inhibited DSS‑induced expression of IL‑6 in colon tissues. Finally, the increased phosphorylation level of STAT3, induced either by DSS in experimental mice or by IL‑6 in the differentiated human colorectal carcinoma cells, was significantly suppressed by PZH. These results suggest that the inhibition of IL‑6/STAT3 signaling is a potential mechanism by which PZH is used in the treatment of UC.

Evaluation of interleukin-6 and its soluble receptor components sIL-6R and sgp130 as markers of inflammation in inflammatory bowel diseases

PURPOSE

Interleukin-6 (IL-6) production and signalling are increased in the inflamed mucosa in inflammatory bowel diseases (IBD). As published serum levels of IL-6 and its soluble receptors sIL-6R and sgp130 in IBD are from small cohorts and partly contradictory, we systematically evaluated IL-6, sIL-6R and sgp130 levels as markers of disease activity in Crohn's disease (CD) and ulcerative colitis (UC).

METHODS

Consecutive adult outpatients with confirmed CD or UC were included, and their disease activity and medication were monitored. Serum from 212 CD patients (815 measurements) and 166 UC patients (514 measurements) was analysed, and 100 age-matched healthy blood donors were used as controls.

RESULTS

IL-6 serum levels were significantly elevated in active versus inactive CD and UC, also compared with healthy controls. However, only a fraction of IBD patients showed increased serum IL-6. IL-6 levels ranged up to 32.7 ng/mL in active CD (> 5000-fold higher than in controls), but also up to 6.9 ng/mL in inactive CD. Increases in active UC (up to 195 pg/mL) and inactive UC (up to 27 pg/mL) were less pronounced. Associations between IL-6 serum levels and C-reactive protein concentrations as well as leukocyte and thrombocyte counts were observed. Median sIL-6R and sgp130 levels were only increased by up to 15%, which was considered of no diagnostic significance.

CONCLUSIONS

Only a minority of IBD patients shows elevated IL-6 serum levels. However, in these patients, IL-6 is strongly associated with disease activity. Its soluble receptors sIL-6R and sgp130 do not appear useful as biomarkers in IBD.

Tofacitinib as Induction and Maintenance Therapy for Ulcerative Colitis

BACKGROUND

Tofacitinib, an oral, small-molecule Janus kinase inhibitor, was shown to have potential efficacy as induction therapy for ulcerative colitis in a phase 2 trial. We further evaluated the efficacy of tofacitinib as induction and maintenance therapy.

METHODS

We conducted three phase 3, randomized, double-blind, placebo-controlled trials of tofacitinib therapy in adults with ulcerative colitis. In the OCTAVE Induction 1 and 2 trials, 598 and 541 patients, respectively, who had moderately to severely active ulcerative colitis despite previous conventional therapy or therapy with a tumor necrosis factor antagonist were randomly assigned to receive induction therapy with tofacitinib (10 mg twice daily) or placebo for 8 weeks. The primary end point was remission at 8 weeks. In the OCTAVE Sustain trial, 593 patients who had a clinical response to induction therapy were randomly assigned to receive maintenance therapy with tofacitinib (either 5 mg or 10 mg twice daily) or placebo for 52 weeks. The primary end point was remission at 52 weeks.

RESULTS

In the OCTAVE Induction 1 trial, remission at 8 weeks occurred in 18.5% of the patients in the tofacitinib group versus 8.2% in the placebo group (P=0.007); in the OCTAVE Induction 2 trial, remission occurred in 16.6% versus 3.6% (P<0.001). In the OCTAVE Sustain trial, remission at 52 weeks occurred in 34.3% of the patients in the 5-mg tofacitinib group and 40.6% in the 10-mg tofacitinib group versus 11.1% in the placebo group (P<0.001 for both comparisons with placebo). In the OCTAVE Induction 1 and 2 trials, the rates of overall infection and serious infection were higher with tofacitinib than with placebo. In the OCTAVE Sustain trial, the rate of serious infection was similar across the three treatment groups, and the rates of overall infection and herpes zoster infection were higher with tofacitinib than with placebo. Across all three trials, adjudicated nonmelanoma skin cancer occurred in five patients who received tofacitinib and in one who received placebo, and adjudicated cardiovascular events occurred in five who received tofacitinib and in none who received placebo; as compared with placebo, tofacitinib was associated with increased lipid levels.

CONCLUSIONS

In patients with moderately to severely active ulcerative colitis, tofacitinib was more effective as induction and maintenance therapy than placebo. (Funded by Pfizer; OCTAVE Induction 1, OCTAVE Induction 2, and OCTAVE Sustain ClinicalTrials.gov numbers, NCT01465763 , NCT01458951 , and NCT01458574 , respectively.).

Regulation of human intestinal T-cell responses by type 1 interferon-STAT1 signaling is disrupted in inflammatory bowel disease

Type 1 interferon (IFN-1) promotes regulatory T-cell function to suppress inflammation in the mouse intestine, but little is known about IFN-1 in the human gut. We therefore assessed the influence of IFN-1 on CD4+ T-cells isolated from human colon tissue obtained from healthy controls or patients with inflammatory bowel disease (IBD). Immunofluorescent imaging revealed constitutive expression of IFNβ in human intestinal tissue, and colonic T-cells were responsive to exogenous IFN-1 as assessed by phosphorylation of signal transduction and activator of transcription 1 (pSTAT1) and induction of interferon stimulated genes (ISGs). Unlike their blood counterparts, intestinal T-cells from non-inflamed regions of IBD colon displayed enhanced responsiveness to IFN-1, increased frequency of pSTAT1+ cells, and greater induction of ISGs upon IFN-1 exposure in vitro. In healthy tissue, antibody neutralization of IFNβ selectively reduced T-cell production of the pro-regulatory cytokine interleukin-10 (IL-10) and increased IFNγ synthesis. In contrast, neutralization of IFNβ in IBD tissue cultures increased the frequency of T-cells producing inflammatory cytokines but did not alter IL-10 expression. These data support a role for endogenous IFN-1 as a context-dependent modulator of T-cell function that promotes regulatory activity in healthy human intestine, but indicate that the IFN-1/STAT1 pathway is dysregulated in inflammatory bowel disease.

The Features of Fecal and Ileal Mucosa-Associated Microbiota in Dairy Calves during Early Infection with Mycobacterium avium Subspecies paratuberculosis

Current diagnostic tests for Johne's disease (JD), a chronic granulomatous inflammation of the gastrointestinal tract of ruminants caused by Mycobacterium avium subspecies paratuberculosis (MAP), lack the sensitivity to identify infected animals at early (asymptomatic) stages of the disease. The objective was to determine the pattern of MAP-associated dysbiosis of intestinal microbiota as a potential biomarker for early detection of infected cattle. To that end, genomic DNA was extracted from ileal mucosa and fecal samples collected from 28 MAP-positive and five control calves. High-throughput Illumina sequencing of the V4 hypervariable region of the 16S rRNA gene was used for community profiling of ileal mucosa-associated (MAM) or fecal microbiota. The PERMANOVA analysis of unweighted UniFrac distances revealed distinct clustering of ileal MAM (P = 0.049) and fecal microbiota (P = 0.068) in MAP-infected vs. control cattle. Microbiota profile of MAP-infected animals was further investigated by linear discriminant analysis effective size (LEfSe); several bacterial taxa within the phylum Proteobacteria were overrepresented in ileal MAM of control calves. Moreover, based on reconstructed metagenomes (PICRUSt) of ileal MAM, functional pathways associated with MAP infection were inferred. Enrichment of lysine and histidine metabolism pathways, and underrepresentation of glutathione metabolism and leucine and isoleucine degradation pathways in MAP-infected calves suggested potential contributions of ileal MAM in development of intestinal inflammation. Finally, simultaneous overrepresentation of families Planococcaceae and Paraprevotellaceae, as well as underrepresentation of genera Faecalibacterium and Akkermansia in the fecal microbiota of infected cattle, served as potential biomarker for identifying infected cattle during subclinical stages of JD. Collectively, based on compositional and functional shifts in intestinal microbiota of infected cattle, we inferred that this dynamic network of microorganisms had an active role in intestinal homeostasis.

Corticotropin-Releasing Hormone Receptor 2 Signaling Promotes Mucosal Repair Responses after Colitis

The corticotropin-releasing hormone family mediates functional responses in many organs, including the intestine. Activation of corticotropin-releasing hormone receptor 2 (CRHR2) in the colonic mucosa promotes inflammation during acute colitis but inhibits inflammation during chronic colitis. We hypothesized that specific modulation of CRHR2 signaling in the colonic mucosa can promote restoration of the epithelium through stimulation of cell proliferative, migratory, and wound healing responses. Mucosal repair was assessed after dextran sodium sulfate (DSS)-induced colitis in mice receiving intracolonic injections of a CRHR2 antagonist or vehicle and in Crhr2(-/-) mice. Histologic damage, cytokine expression, terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling, and Ki-67 immunoreactivity were evaluated. Cell viability, proliferation, and migration were compared between parental and CRHR2-overexpressing colonic epithelial cells. Protein lysates were processed for phosphoprotein assays and a wound healing assay performed in vitro. Administration of a CRHR2 antagonist after DSS-induced colitis increased disease activity, delayed healing, and decreased epithelial cell proliferation in vivo. Colons from these mice also showed increased apoptosis and proinflammatory cytokine expression. Compared with controls, Crhr2(-/-) mice showed increased mortality in the DSS healing protocol. CRHR2-overexpressing cells had increased proliferation and migration compared with parental cells. Wound healing and signal transducer and activator of transcription 3 activity were elevated in CRHR2-overexpressing cells after urocortin 2 and IL-6 treatment, suggesting advanced healing progression. Our results suggest that selective CRHR2 activation may provide a targeted approach to enhance mucosal repair pathways after colitis.

The phosphatase DUSP2 controls the activity of the transcription activator STAT3 and regulates TH17 differentiation

Deregulation of the TH17 subset of helper T cells is closely linked with immunological disorders and inflammatory diseases. However, the mechanism by which TH17 cells are regulated remains elusive. Here we found that the phosphatase DUSP2 (PAC1) negatively regulated the development of TH17 cells. DUSP2 was directly associated with the signal transducer and transcription activator STAT3 and attenuated its activity through dephosphorylation of STAT3 at Tyr705 and Ser727. DUSP2-deficient mice exhibited severe susceptibility to experimental colitis, with enhanced differentiation of TH17 cells and secretion of proinflammatory cytokines. In clinical patients with ulcerative colitis, DUSP2 was downregulated by DNA methylation and was not induced during T cell activation. Our data demonstrate that DUSP2 is a true STAT3 phosphatase that modulates the development of TH17 cells in the autoimmune response and inflammation.

Allicin Alleviates Dextran Sodium Sulfate- (DSS-) Induced Ulcerative Colitis in BALB/c Mice

The objective of this study is to evaluate the effect of allicin (10 mg/kg body weight, orally) in an experimental murine model of UC by administering 2.5% dextran sodium sulfate (DSS) in drinking water to BALB/c mice. DSS-induced mice presented reduced body weight, which was improved by allicin administration. We noted increases in CD68 expression, myeloperoxidase (MPO) activities, and Malonaldehyde (MDA) and mRNA levels of proinflammatory cytokines, such as tumor necrosis factor- (TNF-) α, interleukin- (IL-) 1β, IL-6, and IL-17, and decrease in the activities of enzymic antioxidants such as superoxide dismutase (SOD), Catalase (CAT), Glutathione reductase (GR), and Glutathione peroxidase (GPx) in DSS-induced mice. However, allicin treatment significantly decreased CD68, MPO, MDA, and proinflammatory cytokines and increased the enzymic antioxidants significantly (P < 0.05). In addition, allicin was capable of reducing the activation and nuclear accumulation of signal transducer and activator of transcription 3 (STAT3), thereby preventing degradation of the inhibitory protein IκB and inducing inhibition of the nuclear translocation of nuclear factor (NF)-κB-p65 in the colonic mucosa. These findings suggest that allicin exerts clinically useful anti-inflammatory effects mediated through the suppression of the NF-κB and IL-6/p-STAT3^Y705 pathways.