Huiling Wang

Pro-inflammatory miR-223 mediates the cross-talk between the IL23 pathway and the intestinal barrier in inflammatory bowel disease.

BackgroundThe IL23/Th17 pathway is essential for the onset of inflammatory bowel disease (IBD), yet the specific mechanism by which this pathway initiates the disease remains unknown. In this study, we identify the mechanisms that mediate cross-talk between the IL23 pathway and the intestinal barrier in IBD.ResultsThe downstream targets of the IL23 pathway were identified by RNA array profiling and confirmed by immunohistochemical staining. The role of miRNAs that interact with IL23 was explored in mice with TNBS-induced colitis. Claudin-8 (CLDN8), a multigene family protein that constitutes the backbone of tight junctions, was identified as a novel target of IL23 in IBD. CLDN8 was significantly downregulated in IBD patients with inflamed colonic mucosa, and in trinitrobenzene sulphonic acid (TNBS) induced colitis in mice. Therapeutic treatment of colitis in mice using an IL23 antibody restored CLDN8 abundance, in parallel with recovery from colitis. In addition, we identify miR-223 as a novel mediator of the crosstalk between the IL23 signal pathway and CLDN8 in the development of IBD. MiR-223 was upregulated in IBD, and its activity was regulated through the IL23 pathway. Antagomir inhibition of miR-223 reactivated CLDN8 and improved a number of signs associated with TNBS-induced colitis in mice.ConclusionsOur study characterizes a new mechanistic pathway in IBD, in which miR-223 interacts with the IL23 pathway by targeting CLDN8. Strategies designed to disrupt this interaction may provide novel therapeutic agents for the management of IBD.

Circulating MicroRNA223 is a New Biomarker for Inflammatory Bowel Disease

Abstract Endoscopy is an important tool in screening and monitoring inflammatory bowel disease (IBD); however, it is invasive, costly, and associated with risks to the patients. Recently, circulating microRNAs (miRNAs) have emerged as promising noninvasive biomarkers. We proposed that the expression of serum microRNA223 (miR-223) could be a biomarker for IBD. Studies were conducted using serum samples from 100 patients with IBD (50 with Crohns disease [CD] and 50 with ulcerative colitis [UC]) and 50 healthy controls. The expression of serum miR-223 was measured by quantitative reverse transcription-polymerase chain reaction. The clinical disease activity was assessed by measurement of the Crohns disease activity index for CD and the Mayo score for UC. Endoscopies were performed and graded according to the simple endoscopic score for CD and the ulcerative colitis endoscopic index of severity scores for UC. Blood samples for the measurement of high-sensitivity C-reactive protein (hs-CRP) and erythrocyte sedimentation rate (ESR) were taken within 1 week before or after endoscopy. Serum miR-223 expression increased 2.2 times in patients with CD and 2.8 times in patients with UC compared with the control group. Most importantly, the level of serum miR-223 was correlated with several indicators of disease activity both in CD and UC. Serum miR-223 demonstrated a higher Spearman r value than ESR and hs-CRP in detecting the disease activity of patients with IBD. Serum miR-223 might be a promising biomarker for monitoring disease activity in IBD patients.

E3 Ubiquitin ligase RNF183 Is a Novel Regulator in Inflammatory Bowel Disease.

BACKGROUND AND AIMS Specific members of the RING finger [RNF] protein family serve as E3 ubiquitin ligases and play important roles in the regulation of inflammation. However, their roles in the pathogenesis of inflammatory bowel disease [IBD] have not been explored. METHODS Genomic microarray of inflamed colon samples from Crohns disease [CD] patients was performed to identify potential up-regulated genes. Expression of the identified highly up-regulated RNF183 gene was subsequently examined by quantitative reverse transcription polymerase chain reaction [qRT-PCR], western blotting and immunohistochemistry of the intestinal tissues of IBD patients and the colons of trinitrobenzene sulphonic acid [TNBS]-induced colitic mice. RNF183-mediated interaction with the NF-κB pathway and ubiquitination of IκBα were examined by siRNA, plasmid transfection, and immunoprecipitation. The miRNA predicted to target RNF183 was explored and its role in the RNF183/ NF-κB pathway was investigated. RESULTS RNF183 was up-regulated in intestinal epithelial cells in IBD patients and in colitic mice. RNF183 promoted intestinal inflammation via the activation of the NF-κB pathway by increasing the ubiquitination and degradation of IκBα. Computational analysis identified putative binding of miR-7 to RNF183. Transfection of intestinal cells with a miR-7 mimic or inhibitor confirmed its negative regulatory effect on RNF183 expression and ubiquitination of IκBα. miR-7 was down-regulated in inflamed colon tissues of IBD patients and colitic mice. CONCLUSIONS RNF183, which is negatively regulated by miR-7, is a novel regulator promoting intestinal inflammation by increasing the ubiquitination and degradation of IκBα, thereby inducing NF-κB activation. The interaction between RNF183-mediated ubiquitination and miRNA may be an important novel epigenetic mechanism in the pathogenesis of IBD.

Enterohepatic Helicobacter Species as a Potential Causative Factor in Inflammatory Bowel Disease: A Meta-Analysis.

AbstractThe Helicobacter species in the gut microbiota comprise Helicobacter pylori (H pylori) and enterohepatic Helicobacter species (EHS), which can colonize the intestinal mucosa. However, it is unclear whether EHS are associated with inflammatory bowel disease (IBD). Therefore, we conducted this meta-analysis to examine the association between EHS and IBD.PubMed, Scopus, Cochrane Library, and Web of Science databases, as well as abstracts from conference proceedings were searched to identify studies that used polymerase chain reaction to detect Helicobacter species in intestinal samples from patients with IBD.After screening, we carefully reviewed 20 of the 2955 identified studies, and performed a meta-analysis of the findings from 14 studies (11 adult studies and 3 pediatric studies) using STATA v12.0. These studies evaluated 1407 individuals, including 433 patients with Crohns disease, 306 patients with ulcerative colitis, and 668 controls. The prevalence of Helicobacter species was higher among the patients with IBD, compared to that among the controls, which corresponded to a pooled risk ratio (RR) of 1.59 (95% confidence interval [CI]: 1.12–2.27). The RRs for adult and pediatric patients with IBD were 1.61 (95% CI: 1.03–2.52) and 1.76 (95% CI: 1.17–2.64), respectively. Compared to the controls, the patients with IBD tended to have a higher prevalence of EHS in the intestinal mucosa (RR: 2.01, 95% CI: 1.36–2.98), although the prevalence of H pylori was not significantly higher (RR: 1.22, 95% CI: 0.77–1.95). Compared to the controls, the RRs for EHS in patients with Crohns disease and ulcerative colitis were 1.72 (95% CI: 1.20–2.47) and 3.27 (95% CI: 0.93–11.44), respectively.It appears that EHS was associated with IBD, while intestinal H pylori infection was not significantly associated with IBD. Further studies are needed to determine the involvement of EHS in the microbiological etiology of IBD.

Pediatric Colonoscopy in South China: A 12-Year Experience in a Tertiary Center

Objective To investigate: 1) the demographics and clinical characteristics, 2) the findings, and 3) the safety and effectiveness in a cohort of Chinese pediatric patients undergoing colonoscopy. Methods The study participants were consecutive patients aged ≤14 years old that underwent their first colonoscopy in the endoscopy center at the First Affiliated Hospital, Sun Yat-sen University between Jan. 1, 2001 and Dec. 31, 2012. Demographic, clinical, endoscopic, and pathological findings were collected. Results The cohort consisted of 322 patients, including 218 boys (67.7%) and 104 girls (32.3%). The median age was 8.0 years old and ranged from 9 months to 14 years old. Hematochezia (48.8%) and abdominal pain/discomfort (41.3%) were the most common presentations preceding pediatric colonoscopy. The caecal intubation success rate was 96.3%. No serious complications occurred during the procedures. A total of 227 patients (70.5%) received a positive diagnosis under endoscopy, including 138 patients with polyps and 53 patients with inflammatory bowel disease (IBD). Among the patients with polyps, 71.0% were juvenile polyps. Comparisons between years 2001–2006 and 2007–2012 showed that the IBD detection rate increased significantly (4.6% vs. 22.4%, P<0.001), while the opposite occurred for the polyp detection rate (73.1% vs. 27.6%, P<0.001). Conclusion Colonoscopy in pediatric patients is a safe and effective procedure. Polyps are the primary finding during colonoscopy. In South China there has been an increase in pediatric patients diagnosed with IBD over the past decade. However, a large epidemiological study is needed to confirm our findings.

TNFAIP6 is a potential biomarker of disease activity in inflammatory bowel disease.

AIM Ideal biomarkers are needed for evaluating the activity of inflammatory bowel disease (IBD). We aimed to investigate the value of TNFAIP6 as a biomarker. MATERIALS & METHODS Inflamed colonic samples and serum samples were collected from patients with Crohns disease (CD), patients with ulcerative colitis (UC), and normal controls. SPSS 18.0 was used for statistical analysis. RESULTS Serum TNFAIP6 was higher in IBD patients than in normal controls and correlated with the inflammatory indicators. Compared with active patients, TNFAIP6 was decreased in both CD and UC patients in remission. Furthermore, TNFAIP6 concentrations consistent with TNF-α level, correlated well with disease location and extent of both CD and UC. CONCLUSION Serum TNFAIP6 may be a promising biomarker for evaluating the disease activity of IBD, demonstrating the diagnostic value in disease location differentiation.

Cytokine IL9 Triggers the Pathogenesis of Inflammatory Bowel Disease Through the miR21-CLDN8 Pathway

Background Cytokine interleukin-9 (IL9) plays an essential role in the pathogenesis of inflammatory bowel disease. However, the molecular mechanism underlying the IL9 pathway remains unknown. Here, we initiate a series of studies to characterize the essential components of this pathway. Methods The expression of IL9 in colon biopsies from Crohns disease (CD) and controls were examined by quantitative polymerase chain reaction, immunoblot, and immunohistochemistry. The trinitrobenzene sulfonic acid (TNBS)-induced colitis model was used to verify the therapeutic efficiency of anti-IL9 mAb. Bioinformatics analysis was performed to predict putative candidate microRNAs that mediate the crosstalk between the IL9 proinflammatory signal and the downstream target gene in intestinal barrier function. Caco-2, NCM460, and SW480 cells were used to assess the specific pathway in vitro. Results We demonstrated the proinflammatory role of IL9 in the colonic mucosa of patients with CD. The junction complex protein Claudin 8 (CLDN8) was identified as a critical downstream component of the IL9 inflammatory cascade. Anti-IL9 treatment alleviated TNBS-induced colitis by restoring CLDN8 levels in the colonic mucosa. Notably, we characterized miR21 as a critical player that mediates the crosstalk between the proinflammatory IL9 and the downstream CLDN8 in both in vitro and in vivo models. Conclusions Our results, for the first time, uncover a critical role of miR21 and CLDN8 in the complex network that IL9 regulates the intestinal epithelium barrier in the pathogenesis of CD. Interventional blockade of the IL9-miR21-CLDN8 pathway could be a novel therapeutic approach for the management of CD.