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Background & aimsAlterations in microRNA (miRNA) and in the intestinal barrier are putative risk factors for irritable bowel syndrome (IBS). We aimed to identify differentially expressed colonic mucosal miRNAs, their targets in IBS compared to healthy controls (HCs), and putative downstream pathways.MethodsTwenty-nine IBS patients (15 IBS with constipation [IBS-C], 14 IBS with diarrhea [IBS-D]), and 15 age-matched HCs underwent sigmoidoscopy with biopsies. A nCounter array was used to assess biopsy specimen-associated miRNA levels. A false discovery rate (FDR) < 10% was considered significant. Real-time polymerase chain reaction (PCR) was used to validate differentially expressed genes. To assess barrier function, trans-epithelial electrical resistance (TEER) and dextran flux assays were performed on Caco-2 intestinal epithelial cells that were transfected with miRNA-inhibitors or control inhibitors. Protein expression of barrier function associated genes was confirmed using western blots.ResultsFour out of 247 miRNAs tested were differentially expressed in IBS compared to HCs (FDR < 10%). Real-time PCR validation suggested decreased levels of miR-219a-5p and miR-338-3p in IBS (P = .026 and P = .004), and IBS-C (P = .02 and P = .06) vs. HCs as the strongest associations. Inhibition of miR-219a-5p resulted in altered expression of proteasome/barrierfunction genes. Functionally, miR-219a-5p inhibition enhanced the permeability of intestinal epithelial cells as TEER was reduced (25-50%, P < .05) and dextran flux wasincreased (P < .01). Additionally, inhibition of miR-338-3p incells caused alterations in the mitogen-activated protein kinase (MAPK) signaling pathway genes.ConclusionTwomicroRNAs that potentially affect permeability and visceral nociception were identified to be altered in IBS patients. MiR-219a-5p and miR-338-3p potentially alter barrier function and visceral hypersensitivity via neuronal and MAPK signaling and could be therapeutic targets in IBS.

Background & Aims Altered levels and functions of microRNAs (miRs) have been associated with inflammatory bowel diseases (IBDs), although little is known about their roles in pediatric IBD. We investigated whether colonic mucosal miRs are altered in children with ulcerative colitis (UC). Methods We used a library of 316 miRs to identify those that regulate phosphorylation of signal transducer and activator of transcription 3 (STAT3) in NCM460 human colonocytes incubated with interleukin-6. Levels of miR-124 were measured by real-time polymerase chain reaction analysis of colon biopsies from pediatric and adult patients with UC and patients without IBD (controls), and of HCT-116 colonocytes incubated with 5-aza-2′-deoxycytidine (5-AZA). Methylation of the MIR124 promoter was measured by quantitative methylation-specific polymerase chain reaction. Results Levels of phosphorylated STAT3 and the genes it regulates (encoding vascular endothelial growth factor (VEGF), BCL2, BCLXL, and matrix metallopeptidase 9 [MMP9]) were increased in pediatric patients with UC compared with control tissues. Overexpression of miR-124, let-7, miR-125, miR-26, or miR-101 reduced STAT3 phosphorylation by ≥75% in NCM460 cells; miR-124 had the greatest effect. miR-124 was down-regulated specifically in colon tissues from pediatric patients with UC and directly targeted STAT3 messenger RNA (mRNA). Levels of miR-124 were decreased, whereas levels of STAT3 phosphorylation increased in colon tissues from pediatric patients with active UC compared with those with inactive disease. In addition, levels of miR-124 and STAT3 were inversely correlated in mice with experimental colitis. Down-regulation of miR-124 in tissues from children with UC was attributed to hypermethylation of its promoter region. Incubation of HCT-116 colonocytes with 5-AZA up-regulated miR-124 and reduced levels of STAT3 mRNA. Conclusions miR-124 appears to regulate the expression of STAT3. Reduced levels of miR-124 in colon tissues of children with active UC appear to increase expression and activity of STAT3, which could promote inflammation and the pathogenesis of UC in children. © 2013 by the AGA Institute.

Neurotensin promotes inflammation and colon cancer via the neurotensin-1 receptor (NTR1). MicroRNAs (miR) regulate protein synthesis by degrading or preventing translation of mRNAs. We analyzed expression of 365 different microRNAs by human colonic epithelial cells (NCM460) after activation of NTR1.We performed microarray analysis of mRNA expression by neurotensin-stimulated NCM460 cells that overexpressed NTR1. Nuclear factor-κB (NF-κB) binding sites were identified and tumorigenesis was assessed using soft agar assays and xenograft analysis of severe combined immunodeficiency mice. Targets of neurotensin-regulated microRNAs were identified via bioinformatic, real-time polymerase chain reaction, and immunoblot analyses. We analyzed RNA samples from human normal colon and tumor samples.Neurotensin stimulated differential expression of 38 microRNAs, including miR-21 and miR-155, which have been associated with tumor growth and contain NF-κB binding sites. Neurotensin expression increased colony formation by HCT-116 cells. Blocking miR-21 and/or miR-155 prevented colony formation (P.001). In mice, intraperitoneal administration of neurotensin increased the growth rate of HCT-116 xenograft tumors; blocking miR-21 and/or miR-155 slowed this tumor growth. Neurotensin activated Akt in HCT-116 cells; this effect was inhibited by blocking miR-21 and/or miR-155 (P.001). Neurotensin activated AKT through miR-155-mediated suppression of the phosphatase protein phosphatase 2A catalytic subunit alpha (PPP2CA). Levels of phosphatase and tensin homolog (PTEN) and suppressor of cytokine signaling 1 (SOCS1) mRNA, potential targets of miR-21 and miR-155, respectively, were down-regulated by these miRs. Levels of NTR1, miR-21, and miR-155 increased significantly in human colon tumor samples, compared with normal tissues, whereas PPP2CA, SOCS1, and PTEN mRNAs were reduced significantly.NTR1 activation stimulates expression of miR-21 and miR-155 in colonocytes, via Akt and NF-κB, to down-regulate PTEN and SOCS1 and promote growth of tumors in mice. Levels of NTR1, miR-21, and miR-155 increase in human colon tumor samples and correlate with tumor stage.

AIM: Ulcerative colitis (UC) is a chronic inflammatory disease of the colon and rectum distinguished by relapsing and remitting gastrointestinal and systemic symptoms. Mesalamine (5-aminosalicylic acid; 5-ASA) has proven efficacy in the induction and maintenance of disease remission in patients with mild-to-moderate UC. This phase 1, multicenter, randomized, open-label study (NCT01130844) assessed the pharmacokinetic and safety profiles of 5-ASA and its major metabolite, acetyl-5-ASA (Ac-5-ASA), after administration of once-daily MMX mesalamine to children and adolescents with UC. METHODS: Study participants aged 5-17 years, with a UC diagnosis of ≥3 months were randomized to MMX mesalamine 30, 60, or 100 mg/kg/day (stratified by body weight) for 7 days. To achieve these doses in children, smaller-sized 300 mg and 600 mg tablets were developed for this study to augment the existing approved 1200 mg MMX mesalamine tablet. Patients were administered MMX mesalamine at home on Days 1-4 and on site on Days 5-7 when subjects attended for pharmacokinetic blood and urine sampling and for safety assessments. Plasma and urine concentrations of 5-ASA and Ac-5-ASA were determined by a validated LC/MS/MS assay. Key pharmacokinetic parameters for 5-ASA and Ac-5-ASA included maximum concentration (Cmax,ss), time of Cmax,ss (tmax), area under the curve for one dose interval (AUCss), and renal clearance (CLR), and percent of dose absorbed. RESULTS: A total of 52 patients (30F:22M with mean [standard deviation] age of 13.3 [3.06] years and median [range] time since UC diagnosis of 1.83 [0.2, 9.6] years) were randomized and treated: 21 at 30 mg/kg; 22 at 60 mg/kg; and 9 at 100 mg/kg. Steady state plasma concentrations for 5-ASA and Ac5-ASA were attained by Day 5 for all doses. On Day 7, mean AUCss and Cmax,ss for 5-ASA and Ac-5-ASA increased in a dose proportional manner between 30 and 60 mg/kg/day doses. Mean percentage of 5-ASA absorbed from MMX mesalamine was 29.4%, 27.0%, and 22.1%, for 30, 60, and 100 mg/kg/day doses, respectively. Mean CLR ranged from 5.0-6.5 L/h for 5-ASA and 10.0-16.2 L/h for Ac-5-ASA. The incidence of treatment-emergent adverse events was 19.2% overall. Events were similar among different dose and age groups, with no novel safety signals reported. CONCLUSIONS: The pharmacokinetic profile of 5-ASA and Ac-5ASA in children/adolescents with UC receiving MMX mesalamine across all dose levels was similar to the pharmacokinetic profile in historical adult data. MMX mesalamine was welltolerated at all doses and in all age groups; no new safety signals were identified.

G A A b st ra ct s or constructs overexpressing HA-tagged 14-3-3σ plasmids. 14-3-3σ, Rictor (an mTORC2 protein), MUC2, cleaved Notch1, p-Akt(S473), Akt1 and Akt2 protein expression was determined by Western blotting. Enterocyte differentiation was induced by treatment of HT29 cells with sodium butyrate (NaBT) and assayed by measuring intestinal alkaline phosphatase (IAP) activity, an enterocyte differentiation marker. The expression of the goblet cell differentiation marker MUC2 and the Notch1 target gene HES1 was also determined by RT-PCR. The interaction between Akt andmTORC2was determined by immunoprecipitation followed by Western blot analysis. RESULTS. Knockdown of 14-3-3 σ did not alter basal or NaBT-induced of IAP activity. However, knockdown of 14-3-3 σ significantly increased MUC2 expression associated with the inhibition of Notch1 signaling as shown by decreased cleaved Notch1 protein and decreased HES1 mRNA expression. These results suggested that 14-3-3σ plays an important role in the regulation of goblet cell differentiation without impacting enterocyte differentiation. In addition, overexpression of 14-3-3σ decreased Akt (Ser473) phosphorylation and knockdown of either Akt1 or Akt2 decreased MUC2 expression. Moreover, overexpression of 14-3-3σ decreased the interaction between Akt and mTORC2. These results suggest that 14-3-3σmay regulate Akt activity through the inhibition of mTORC2-mediated Akt (Ser473) phosphorylation. CONCLUSIONS. Our results suggest a role for 14-3-3σ in goblet cell differentiation through the alteration of TSC2, Notch and Akt signaling pathways. Importantly, our data demonstrate that 14-3-3 σ regulation of Akt phosphorylation is mediated through the altered interaction between mTORC2 and Akt.