Pathophysiology Of Ulcerative Colitis Research Articles

Potential of using an engineered indole lactic acid producing Escherichia coli Nissle 1917 in a murine model of colitis

The gut microbiome is a significant factor in the pathophysiology of ulcerative colitis (UC), prompting investigations into the use of probiotic therapies to counter gastrointestinal inflammation. However, while much attention has been given to the therapeutic potential of microbes at the species and strain level, the discovery and application of their metabolic products may offer more precise and controlled solutions in battling disease. In this work, we examined the therapeutic potential of indole lactic acid (ILA) to alleviate inflammation in a murine model of colitis. A previously constructed ILA-producing Escherichia coli Nissle 1917 strain (EcN aldh) and its isogenic non-ILA producing counterpart (EcN) were studied in a murine model of Dextran Sodium Sulfate (DSS) induced colitis. The colitic animals suffered from severe colitic symptoms, with no differentiation between the groups in body weight loss and disease activity index. However, three days after cessation of DSS treatment the EcN aldh–treated mice showed signs of reduced intestinal inflammation, as manifested by lower concentrations of fecal lipocalin-2. Additionally, expression analysis of the inflamed tissue revealed distinct effects of the EcN aldh strain on proteins associated with intestinal health, such as TFF3, occludin and IL-1β expression. These results show no impact of EcN or EcN aldh on acute DSS-induced colitis, but suggest that in particular EcN aldh may assist recovery from intestinal inflammation.

Antagomir of miR-31-5p modulates macrophage polarization via the AMPK/SIRT1/NLRP3 signaling pathway to protect against DSS-induced colitis in mice.

Macrophage-driven immune dysfunction of the intestinal mucosa is involved in the pathophysiology of ulcerative colitis (UC). Emerging evidence indicates that there is an elevation in miR-31-5p levels in UC, which is accompanied by a downregulation of adenosine 5'-monophosphate (AMP)-activated protein kinase (AMPK) expression. Nevertheless, the precise influence of miR-31-5p on macrophage polarization and the integrity of the intestinal epithelial barrier in UC remains to be fully elucidated. This study explored the role of miR-31-5p and AMPK in UC through a bioinformatics investigation. It investigated the potential of miR-31-5p antagomir to shift macrophages from pro-inflammatory M1 phenotype to anti-inflammatory M2 phenotype and enhance the intestinal mucosal barrier in DSS-induced UC mice. Additionally, RAW264.7 cells stimulated with LPS were employed to confirm the reversal of miR-31-5p antagomir's therapeutic effect under AMPK inhibition. The findings demonstrated that miR-31-5p antagomir penetrated colonic tissues and ameliorated DSS-induced experimental colitis. Transformation of spleen and mesenteric lymph node macrophages from M1 to M2 type was seen in the DSS+miR-31-5p antagomir group. AMPK/Sirt1 expression increased while NLRP3 expression decreased. Expression of M2-related genes and proteins was enhanced and that of the M1 phenotype suppressed. Tight junction proteins, ZO-1 and occludin, were increased. The therapeutic effects of miR-31-5p antagomir transfection into RAW264.7 cells were repressed when AMPK expression was inhibited. Therefore, our results suggest that suppression of miR-31-5p expression transformed macrophages from M1 to M2, ameliorated inflammation and repaired the intestinal epithelium to alleviate DSS-induced colitis. AMPK/Sirt1/NLRP3 was involved.

Hippocampal and gut AMPK activation attenuates enterocolitis-like symptoms and co-occurring depressive-like behavior in ulcerative colitis model mice: Involvement of brain-gut autophagy

Patients with inflammatory bowel disease, including ulcerative colitis (UC) and Crohn's disease, have a high incidence of psychiatric disorders, including depression and anxiety. However, the underlying pathogenic mechanism remains unknown. Dextran sulfate sodium (DSS)-treated mice, a model of UC, exhibit depressive-like behavior and reduced adenosine monophosphate-activated protein kinase (AMPK) activity, which regulates various physiological functions in the brain and gut. However, comprehensive studies on UC pathophysiology with co-occurring depression focused on brain-gut AMPK activity are lacking. Therefore, we aimed to investigate whether resveratrol (RES), an AMPK activator, prevented DSS-induced UC-like symptoms and depressive-like behavior. DSS treatment induced UC-like pathology and depressive-like behavior, as assessed via the tail suspension test. Moreover, western blotting and immunohistochemical studies revealed that DSS increased p-p70S6 kinase (Thr389), p62, tumor necrosis factor-α, interleukin (IL)-1β, IL-18, NLR family pyrin domain containing 3 (NLRP3), cleaved caspase-1, cleaved Gasdermin-D (GSDMD), and cleaved caspase-3 expression levels in the rectum and hippocampus, and increased CD40, iNOS, and Kelch-like ECH-associated protein 1 expression levels, and the number of Iba1-positive cells in the hippocampus, and decreased p-AMPK and LC3II/I expression levels, and the number of NF-E2-related factor 2 (Nrf2)-positive cells, and reduced neurogenesis in the hippocampus. These changes were reversed by the RES administration. RES also enhanced PGC1α and SOD1 expression in the hippocampus of DSS-treated male mice. Moreover, NLRP3 staining was observed in the neurons and microglia, and cleaved GSDMD staining in neurons in the hippocampus of DSS-treated mice. Notably, RES prevented UC-like pathology and depressive-like behavior and enhancement of autophagy, decreased rectal and hippocampal inflammatory cytokines and inflammasome, and induced the Nrf2-PGC1α-SOD1 pathway in the hippocampus, resulting in neurogenesis in the hippocampal dentate gyrus. Our findings suggest that brain-gut AMPK activation may be an important therapeutic strategy in patients with UC and depression.

Modulatory Role of Galectin-1 in Ulcerative Colitis with Comorbid Metabolic Syndrome

Abstract Metabolic syndrome (MetS) and ulcerative colitis (UC) are widespread health conditions characterized by chronic, low-grade inflammation. Galectin-1 (Gal-1), an immunomodulatory peptide mainly secreted from adipose tissue, could potentially play a crucial role in mitigating these conditions. This cross-sectional study explores the involvement of Gal-1 in MetS and UC within a cohort of 75 patients, newly diagnosed with UC. The MetS subgroup displayed increased fecal Gal-1 levels compared to those without MetS. Furthermore, Gal-1 showed predominance over pro-inflammatory cytokines, including TNF-α, IL-6, and IL-17, in these subjects. These findings emphasize the potential involvement of Gal-1 in the pathophysiology of UC and MetS, presenting it as a promising diagnostic biomarker and therapeutic target for these conditions.

GRK2 Mediates Macrophage Polarization by Regulating EP4-cAMP-pCREB Signaling in Ulcerative Colitis and the Therapeutic Effect of Paroxetine on Mice with DSS-Induced Colitis.

G protein-coupled receptor kinase 2 (GRK2) is one of the cytosolic enzymes, and GRK2 translocation induces prostaglandin E2 receptor 4 (EP4) over-desensitization and reduces the level of cyclic adenosine monophosphate (cAMP) to regulate macrophage polarization. However, the role of GRK2 in the pathophysiology of ulcerative colitis (UC) remains unclear. In this study, we investigated the role of GRK2 in macrophage polarization in UC, using biopsies from patients, a GRK2 heterozygous mouse model with dextran sulfate sodium (DSS)-induced colitis, and THP-1 cells. The results showed that a high level of prostaglandin E2 (PGE2) stimulated the receptor EP4 and enhanced the transmembrane activity of GRK2 in colonic lamina propria mononuclear cells (LPMCs), resulting in a down-regulation of membrane EP4 expression. Then, the suppression of cAMP-cyclic AMP responsive element-binding (CREB) signal inhibited M2 polarization in UC. Paroxetine is acknowledged as one of the selective serotonin reuptake inhibitors (SSRI), which is also considered as a potent GRK2 inhibitor with a high selectivity for GRK2. We found that paroxetine could alleviate symptoms of DSS-induced colitis in mice by regulating GPCR signaling to affect macrophage polarization. Taken together, the current results show that GRK2 may act as a novel therapeutic target in UC by regulating macrophage polarization, and paroxetine as a GRK2 inhibitor may have therapeutic effect on mice with DSS-induced colitis.

DNA Methylation of JAK2 Gene in Intestinal Biopsy and Peripheral Blood Samples of Patients with Ulcerative Colitis

Background: Comprised of two main subtypes (Ulcerative Colitis (UC) and Crohn), inflammatory bowel disease is caused by an interaction between genetic and environmental factors. As of the important role of innate immunity and JAK/STAT signaling pathway, the current study was designed to investigate the methylation status JAK2 gene in blood and tissue samples of patients with UC.
 Methods: Genomic DNA was extracted from blood and intestinal biopsy samples of 28 UC patients and 28 controls. After bisulfite DNA conversion, real-time quantitative multiplex methylation specific PCR (QM-MSP) method was applied in order to assess JAK2 promotor methylation status.
 Results: The JAK2 promotor in the intestinal biopsy samples was significantly hypermethylated in UC as the mean of unmethylated DNA was 1.255±1.865 in the patients group, while it was 1.292±4.726 in control group.
 Conclusion: Hypermathylation of JAK2 gene may play a part in pathophysiology of UC which could result in gene silencing.

Reduced abundance of butyric acid-producing bacteria in the ileal mucosa-associated microbiota of ulcerative colitis patients.

Compositional changes in the microbiota are associated with various inflammatory diseases, including ulcerative colitis (UC). Aim: This study aimed to investigate the mucosa-associated microbiota (MAM) in patients with UC and its difference related with disease activity and classification. Brush samples were collected from the terminal ileum and sigmoid colon during endoscopic procedures. The microbiota of samples was profiled using the Illumina MiSeq platform. The V3-V4 regions of the gene encoding 16S rRNA (460 bp) were amplified using PCR. Fifty UC patients and twenty healthy controls were enrolled. UC patients displayed significantly reduced α-diversity in both the ileum and sigmoid colon compared to controls. A difference in β-diversity in the unweighted analysis was observed between the two groups. The abundance of Lactobacillus and Veillonella was significantly higher and that of Butyricicoccus, Ruminococcus and Lachnospiraceae was significantly lower in the ileum of UC patients than in controls. The abundance of Odoribacter in the ileum was significantly lower in left-sided colitis and pancolitis patients than in proctitis patients and lower in patients with highly severe disease activity than with mild disease activity. The reduction in abundance of butyric acid-producing bacteria, especially Odoribacter, in ileal MAM may play an important role in the pathophysiology of UC.

Role of microRNAs in the Pathophysiology of Ulcerative Colitis

Ulcerative colitis (UC) is an intractable disorder characterized by a chronic inflammation of the colon. Studies have identified UC as a multifactorial disorder affected by both genetic and environmental factors; however, the precise mechanism remains unclear. Recent advances in the field of microRNA (miRNA) research have identified an association between this small non-coding RNA in the pathophysiology of UC and altered miRNA expression profiles in patients with UC. Nevertheless, the roles of individual miRNAs are uncertain due to heterogeneity in both research samples and clinical backgrounds. In this review, we focus on miRNA expression in colonic mucosa where inflammation occurs in UC and discuss the potential roles of individual miRNAs in disease development, outlining the pathophysiology of UC.

P278 Type IV collagen formation/degradation ratio predicts response to infliximab induction therapy in patients with Ulcerative Colitis

Abstract Background Up to 50% of patients with ulcerative colitis (UC) do not respond to biological therapies, including TNF-α-antagonists (e.g., infliximab, IFX) and migration inhibitors (e.g., the α4β7-integrin inhibitor vedolizumab, VEDO). Therefore, serological biomarkers that predict therapy response are urgently needed. In this respect, biomarkers of extracellular matrix (ECM) remodeling, including basement membrane (BM) remodeling, and intestinal inflammation may hold promise as these processes play an important role in the pathophysiology of UC. In this study, we aimed to assess the predictive ability of serological biomarkers of ECM turnover and intestinal inflammation with regard to clinical response to IFX and VEDO therapy in patients with UC. Methods Serological biomarkers of collagen formation (PRO-C3, PRO-C4), matrix metalloproteinase (MMP)-mediated collagen degradation (reC1M, C3M, C4M, C4G, C6Ma3) and intestinal inflammation (macrophage activity marker [VICM] and calprotectin degradation fragments [CPa9-HNE]) were measured using neo-epitope solid-phase competitive enzyme-linked immunosorbent assay (ELISA) technology in 80 patients with UC who received either infliximab (IFX, n=26) or vedolizumab (VEDO, n=54) induction therapy. Clinical response to therapy was defined by composite assessment of available Simple Clinical Colitis Activity Index (SCCAI) scores and physician’s global assessments (PGA) derived from clinical records. Logistic regression modelling and receiver operating characteristics (ROC) statistics were used to assess discriminative capacity regarding response to IFX and VEDO. Results Only baseline ratios of type IV collagen formation and degradation (PRO-C4/C4M) were significantly elevated in patients with UC who clinically responded to IFX therapy (P<0.05). In addition, PRO-C4/C4M ratios accurately discriminated responders and non-responders to IFX therapy (area under the curve [AUC]=0.77, P<0.05), also after adjustment for confounding factors (AUC=0.88, P<0.01). Serum VICM levels were elevated in patients not responding to IFX therapy, but did not reach statistical significance (AUC=0.76, P=0.06). None of the biomarkers predicted response to VEDO therapy. Conclusion The baseline ratio of type IV collagen formation/degradation demonstrated high predictive accuracy with regard to response to IFX therapy in patients with UC, which may imply that patients with increased BM formation vs. degradation are more likely to respond. Furthermore, VICM may hold promise as a predictor for non-response to IFX therapy. Serological biomarkers of ECM turnover and intestinal inflammation may aid in predicting response to biological therapy and deserve validation in larger, prospective cohort studies.

Ustekinumab for Ulcerative Colitis

Ustekinumab for Ulcerative Colitis

TRPV Subfamily (TRPV2, TRPV3, TRPV4, TRPV5, and TRPV6) Gene and Protein Expression in Patients with Ulcerative Colitis.

Introduction TRPVs are a group of receptors with a channel activity predominantly permeable to Ca2+. This subfamily is involved in the development of gastrointestinal diseases such as ulcerative colitis (UC). The aim of the study was to characterize the gene and protein expression of the TRPV subfamily in UC patients and controls. Methods We determined by quantitative PCR the gene expression of TRPV2, TRPV3, TRPV4, TRPV5, and TRPV6 in 45 UC patients (29 active UC and 16 remission UC) and 26 noninflamed controls. Protein expression was evaluated in 5 μm thick sections of formalin-fixed, paraffin-embedded tissue from 5 customized severe active UC patients and 5 control surgical specimens. Results TRPV2 gene expression was increased in the control group compared with active UC and remission patients (P = 0.002 and P = 0.05, respectively). TRPV3 gene expression was significantly higher in controls than in active UC patients (P = 0.002). The gene expression of TRPV4 was significantly higher in colonic tissue from patients with remission UC compared with active UC patients (P = 0.05) and controls (P = 0.005). TRPV5 had significantly higher mRNA levels in a control group compared with active UC patients (P = 0.02). The gene expression of TRPV6 was significantly higher in the colonic tissue from patients with active UC compared with the control group (P = 0.05). The protein expression of TRPV2 was upregulated in the mucosa and submucosa from the controls compared with the UC patients (P ≤ 0.003). The protein expression of TRPV3 and TRPV4 was upregulated in all intestinal layers from the controls compared with the UC patients (P < 0.001). TRPV5 was upregulated in the submucosa and serosa from the controls vs. UC patients (P < 0.001). TRPV6 was upregulated in all intestinal layers from the UC patients vs. controls (P ≤ 0.001). Conclusion The TRPV subfamily clearly showed a differential expression in the UC patients compared with the controls, suggesting their role in the pathophysiology of UC.

Osteopathic Primary Care Treatment Options for Ulcerative Colitis

Ulcerative colitis is a multifactorial, chronic inflammatory disease of the bowel that can cause physical, social and emotional injury to the patient. While perhaps not always making the initial diagnosis or providing primary treatment, the primary care physician can play a critical role in providing direction and clarity to the overall treatment plan for the patient. In addition, monitoring for complications or side effects of treatment will help maintain the patient’s optimal health.&#x0D; Methods: A literature search using PubMed, NCBI and WorldCat.org was done using the terms ulcerative colitis treatment, psychosocial association of ulcerative colitis, surgical management of ulcerative colitis, epidemiology of ulcerative colitis, the pathophysiology of ulcerative colitis, probiotics in ulcerative colitis, OMT for ulcerative colitis, and diagnosis of ulcerative colitis. A primary date range of 2015-2019 was used with a secondary search extending back to 1985.&#x0D; Discussion: An Osteopathic approach to the treatment of ulcerative colitis will help the patient remain highly functioning and reduce complications of this disease. By being aware of the various pharmaceutical and non-pharmaceutical treatment options available, one can collaborate with the patient to create a treatment plan to minimize morbidity and increase functional days.

P135 MAJOR GENE REGULATORS AFFECTED IN COLON AND BLOOD OF DEXTRAN SODIUM SULFATE ACUTE COLITIS MURINE MODEL

Abstract Background Dextran sulfate sodium (DSS) ulcerative colitis (UC) murine models have long been used for in vivo studies. DSS is a negatively charged polysaccharide with colitogenic properties. Although the mechanisms by which DSS induces intestinal inflammation are not fully understood, there are several good reasons why the DSS chemical colitis model for investigating the immunopathogenesis mechanism of UC is widely used. These include strong phenotypic clinical manifestations which emulate numerous clinical and histopathological features of human UC, ease of use, low mortality rate and high reproducibility. Here, by using high-throughput RNA sequencing analysis we set to investigate the major predicted gene regulators (GRs) affected by differentially expressed genes in the DSS treated UC model in order to obtain regulatory insights into the pathogenic mechanisms of UC development. Methods A DSS-induced mouse model of UC was established. Total RNA from colon tissue and blood of 3 healthy and 3 DSS-treated mice was extracted and sequenced by Illumina HiSeq 4000. Gene expression levels were obtained by mapping and quantification to the annotated mouse genome. Subsequently, differential gene expression analysis between DSS-treated and control mice both in colon and blood was performed. Ingenuity pathway analysis software (IPA®, Qiagen) was used to predict/identify major GRs affected by significantly differentially expressed genes (SDEGs, FC &amp;gt; |2|, p ≤0.05) in both colon and blood. Results Our analysis revealed how many and which major GRs are affected in DSS-treated mice and also the direction of change as compared to healthy (untreated) mice. In colon, 595 activated and 198 inhibited major GRs (p-value of overlap ≤0.05) in relation to ∼ 3180 SDEGs were identified, while in blood, we identified 205 activated and 62 inhibited GRs (in relation to ∼650 SDEGs). Colon and blood share 181 activated and 41 inhibited GRs. Identified GRs include transcription regulators, cytokines, transmembrane receptors and enzymes that mainly contribute to the development of inflammatory/immune responses. In colon and blood, the top 10 activated and inhibited regulators with the highest positive and negative activation z-score with target molecules as well as expression in the datasets are indicated in Figure 1a and 1b, respectively. Conclusion In this study, we analyzed linkage of GRs to SDEGs through coordinated expression and identified potential major regulators that have significant effect on UC pathogenic-related gene expression. These GRs seem to be the key regulators of transcriptomic changes induced by inflammation. These findings expand our molecular understanding of putative new targets that may be important in the pathophysiology of UC and provide biological insights into the observed expression changes between the UC and healthy controls.

P276 Reactivation of Epstein–Barr virus and cytomegalovirus behaves differently in pathophysiology of ulcerative colitis

Abstract Background Cytomegalovirus (CMV) and Epstein–Barr virus (EBV) are members of the herpesvirus family. CMV reactivation is often complicated with ulcerative colitis (UC) and is known as one of exacerbation factors. However, the association between EBV reactivation and pathophysiology of UC is still unclear. Methods This study enrolled 116 active UC patients who received colonoscopy between January 2005 and January 2019 in Kyoto University Hospital. 244 biopsy specimens were obtained from inflamed colonic mucosa to assess EVB and CMV reactivation. Viral loads of EBV and CMV in inflamed mucosa were measured by real-time PCR assay. The reactivation of those viruses was defined as DNA quantity more than 10 copies/μg DNA. Clinical severity was assessed by Lichtiger index and defined as follow: 4–8 as mild, 9–12 as moderate, and more than 12 as severe. Endoscopic severity was assessed by Mayo endoscopic score. We examined the correlation between the positivity of each viral reactivation and patients’ characteristics or prognosis of UC. Results (1) Median age, Lichtiger score and Mayo endoscopic score at the time to assess the viral reactivations were 36 years-old, 8, and 3, respectively. (2) EBV and CMV reactivation were observed in 127 samples (52.0%) and 73 samples (29.9%), respectively. There was no correlation between EBV and CMV viral load (correlation coefficient 0.19), although a significant correlation between those viral reactivations was observed in active colonic mucosa of UC patients (p = 0.002). (3) The proportion of EBV reactivation was higher in both clinically and endoscopically severe UC patients compared with those with mild activity. On the other hands, there was no association between CMV reactivation and clinical or endoscopic severity. (4) Multivariate analysis indicated risk factors for EBV reactivation as receiving anti-TNF-α antibodies (odds ratio [OR] 4.2) or calcineurin inhibitors (OR 3.5), and CMV reactivation (OR 2.1), respectively. (5) Multivariate analysis also indicated risks for CMV reactivation as steroid-refractory (OR 4.7) and EBV reactivation (OR 2.0). (6) EBV and CMV reactivation did not affect clinical outcomes including the requirement of colectomy or intensification of immunosuppressive treatments and the incidence of colitis-associated cancer, dysplasia and lymphoproliferative disease. Conclusion Reactivation of EBV or CMV may behave differently in pathophysiology of UC. Further studies are required to clarify the role of EBV reactivation on colonic inflammation in UC patients.

682 Investigating the Pathogenesis of Ulcerative Colitis Through Meta-Analysis of Gene Expression Omnibus Data

INTRODUCTION: Ulcerative colitis (UC) is an inflammatory bowel disease that causes inflammation of the colon and rectum, alongside extra-colonic manifestations. The etiology is unclear but is thought to include such factors as genetic predisposition, immune regulation, microbiome, and environmental triggers. Though strides have been made in treatment, the failure of anti-IL13 drugs demonstrates our limited knowledge of UC pathology. Here we use meta-analysis to dissect UC pathogenesis. METHODS: We employed our STARGEO platform to search Gene Expression Omnibus and performed meta-analysis on 465 colon samples from active UC patients, using 326 healthy colon samples as a control. We then analyzed the signature in Ingenuity Pathway Analysis. RESULTS: Our analysis identified granulocyte adhesion and diapedesis, TREM1 signaling, and communication between innate and adaptive immune cells as top canonical pathways. TNF, IFNγ, and IL1 were top upstream regulators with predicted activation. We noted upregulation of the DUOX/DUOXA2 enzyme system, responsible for generating reactive oxygen species. We also found upregulation of calprotectin S100A8, which defines UC severity, and downregulation of the E3 ubiquitin ligase RNF5 responsible for controlling S100A8 expression. Impaired epithelial integrity was suggested by upregulation of matrix metalloproteinases MMP1 and MMP3 and down regulation of claudin 8. Furthermore, downregulation of aquaporin 8 and guanylin suggests loss of absorption. Upregulation of the amino acid transporter SLC6A14 and aldolase B may represent a compensation for loss of absorptive function. We also found metabolic dysfunction through downregulation of phosphoenolpyruvate carboxykinase 1, and UDP-glucuronosyltransferases UGT1A7/A5/A3. Lastly, we found downregulation of several miRNAs including mir-188, 192, 200a/b, 215, and 320. CONCLUSION: UC pathogenesis represents a multifactorial disease process that remains elusive. Here we suggest several mechanisms that may underpin UC development and susceptibility. In a recent study, inverse expression of RNF5 and S100A8 was found to coincide with UC severity and our results give credence to this correlation. Our results also demonstrate the parts that DUOX/DUOXA2 system and loss of epithelial and metabolic integrity have in UC. Lastly, miRNAs have an emerging role in UC and mimic therapy of the downregulated miRNAs we identified may prove efficacious. These results provide novel insights into UC pathophysiology and potential therapeutic avenues.

Diet in the Pathogenesis and Management of Ulcerative Colitis; A Review of Randomized Controlled Dietary Interventions

Epidemiological and experimental studies have suggested that diet is one of the environmental factors that contributes to the onset and pathophysiology of ulcerative colitis. Although many patients suffering from ulcerative colitis attribute their symptoms or disease relapse to dietary factors, only a few well-designed randomized controlled trials have been done to investigate the role of diet in the management of ulcerative colitis. Here, we review the potential mechanisms of the relationship between diet and pathogenesis of ulcerative colitis and summarize randomized controlled dietary interventions that have been conducted in ulcerative colitis patients.

MicroRNA-31 and MicroRNA-155 Are Overexpressed in Ulcerative Colitis and Regulate IL-13 Signaling by Targeting Interleukin 13 Receptor α-1.

Interleukin-13 (IL-13) is an important Type 2 T helper (Th2) cytokine, controlling biological functions in epithelium and has been linked to asthma, atopic dermatitis and ulcerative colitis (UC). Interleukin-13 signals through IL-13 receptor α-1 (IL13RA1 (gene) and IL13Rα1 (protein)), a receptor that can be regulated by microRNAs (miRs). MicroRNAs are small non-coding single-stranded RNAs with a role in several pathologies. However, their relevance in the pathophysiology of UC, a chronic inflammatory condition of the colonic mucosa, is poorly characterised. Here, we determined the expression of IL13Rα1 in UC, its potential regulation by miRs and the subsequent effect on IL-13 signalling. Inflamed mucosa of UC patients showed decreased mRNA and protein expression of IL13RA1 when compared to healthy controls. We show that miR-31 and miR-155 are upregulated in inflamed UC mucosa and that both directly target the 3′ untranslated region of IL13RA1 mRNA. Transfection of miR-31 and miR-155 mimics reduced the expression of IL13RA1 mRNA and protein, and blocked IL-13-dependent phosphorylation of signal transducer and activator of transcription 6 (STAT6) in HT-29 cells, a gut epithelium cell line. Interleukin-13 activation of suppressor of cytokine signaling 1 (SOCS1) and eotaxin-3 (CCL26) expression was also diminished. MicroRNA-31/microRNA-155 mimics also downregulated IL13RA1 in ex vivo human inflamed UC biopsies. We propose that miR-31 and miR-155 have an important role in limiting IL-13 signalling in UC disease.

Insights into the pathophysiology of ulcerative colitis: interleukin-13 modulates STAT6 and p38 MAPK activity in the colon epithelial sodium channel.

Insights into the pathophysiology of ulcerative colitis: interleukin-13 modulates STAT6 and p38 MAPK activity in the colon epithelial sodium channel.

Sphingolipids in neutrophil function and inflammatory responses: Mechanisms and implications for intestinal immunity and inflammation in ulcerative colitis.

Bioactive sphingolipids are regulators of immune cell function and play critical roles in inflammatory conditions including ulcerative colitis. As one of the major forms of inflammatory bowel disease, ulcerative colitis pathophysiology is characterized by an aberrant intestinal inflammatory response that persists causing chronic inflammation and tissue injury. Innate immune cells play an integral role in normal intestinal homeostasis but their dysregulation is thought to contribute to the pathogenesis of ulcerative colitis. In particular, neutrophils are key effector cells and are first line defenders against invading pathogens. While the activity of neutrophils in the intestinal mucosa is required for homeostasis, regulatory mechanisms are equally important to prevent unnecessary activation. In ulcerative colitis, unregulated neutrophil inflammatory mechanisms promote tissue injury and loss of homeostasis. Aberrant neutrophil function represents an early checkpoint in the detrimental cycle of chronic intestinal inflammation; thus, dissecting the mechanisms by which these cells are regulated both before and during disease is essential for understanding the pathogenesis of ulcerative colitis. We present an analysis of the role of sphingolipids in the regulation of neutrophil function and the implication of this relationship in ulcerative colitis.

P019. Informing ulcerative colitis pathophysiology and outcomes through metabolic pofiling

P019. Informing ulcerative colitis pathophysiology and outcomes through metabolic pofiling