miR-16 and miR-103 impact 5-HT4 receptor signalling and correlate with symptom profile in irritable bowel syndrome.

Irritable bowel syndrome (IBS) is a gut-brain disorder involving alterations in intestinal sensitivity and motility. Serotonin 5-HT4 receptors are promising candidates in IBS pathophysiology since they regulate gut motor function and stool consistency, and targeted 5-HT4R selective drug intervention has been proven beneficial in subgroups of patients. We identified a single nucleotide polymorphism (SNP) (rs201253747) c.*61 T > C within the 5-HT4 receptor gene HTR4 to be predominantly present in diarrhoea-IBS patients (IBS-D). It affects a binding site for the miR-16 family and miR-103/miR-107 within the isoforms HTR4b/i and putatively impairs HTR4 expression. Subsequent miRNA-profiling revealed downregulation of miR-16 and miR-103 in the jejunum of IBS-D patients correlating with symptoms. In vitro assays confirmed expression regulation via three 3'UTR binding sites. The novel isoform HTR4b_2 lacking two of the three miRNA binding sites escapes miR-16/103/107 regulation in SNP carriers. We provide the first evidence that HTR4 expression is fine-tuned by miRNAs, and that this regulation is impaired either by the SNP c.*61 T > C or by diminished levels of miR-16 and miR-103 suggesting that HTR4 might be involved in the development of IBS-D.

Performance of Serum microRNAs -122, -192 and -21 as Biomarkers in Patients with Non-Alcoholic Steatohepatitis.

OBJECTIVES: Liver biopsies are the current gold standard in non-alcoholic steatohepatitis (NASH) diagnosis. Their invasive nature, however, still carries an increased risk for patients' health. The development of non-invasive diagnostic tools to differentiate between bland steatosis (NAFL) and NASH remains crucial. The aim of this study is the evaluation of investigated circulating microRNAs in combination with new targets in order to optimize the discrimination of NASH patients by non-invasive serum biomarkers. METHODS: Serum profiles of four microRNAs were evaluated in two cohorts consisting of 137 NAFLD patients and 61 healthy controls. In a binary logistic regression model microRNAs of relevance were detected. Correlation of microRNA appearance with known biomarkers like ALT and CK18-Asp396 was evaluated. A simplified scoring model was developed, combining the levels of microRNA in circulation and CK18-Asp396 fragments. Receiver operating characteristics were used to evaluate the potential of discriminating NASH. RESULTS: The new finding of our study is the different profile of circulating miR-21 in NASH patients (p<0.0001). Also, it validates recently published results of miR-122 and miR-192 to be differentially regulated in NAFL and NASH. Combined microRNA expression profiles with CK18-Asp396 fragment level scoring model had a higher potential of NASH prediction compared to other risk biomarkers (AUROC = 0.83, 95% CI = 0.754-0.908; p<0.001). Evaluation of score model for NAFL (Score = 0) and NASH (Score = 4) had shown high rates of sensitivity (91%) and specificity (83%). CONCLUSIONS: Our study defines candidates for a combined model of miRNAs and CK18-Asp396 levels relevant as a promising expansion for diagnosis and in turn treatment of NASH.

Impact of genetic SLC28 transporter and ITPA variants on ribavirin serum level, hemoglobin drop and therapeutic response in patients with HCV infection.

BACKGROUND & AIMS: In the last decade, pegylated interferon-α (PegIFN-α) plus ribavirin (RBV) was the standard treatment of chronic hepatitis C for genotype 1, and it remains the standard for genotypes 2 and 3. Recent studies reported associations between RBV-induced anemia and genetic polymorphisms of concentrative nucleoside transporters such as CNT3 (encoded by SLC28A3) and inosine triphosphatase (encoded by ITPA). We aimed at studying genetic determinants of RBV kinetics, efficacy and treatment-associated anemia. METHODS: We included 216 patients from two Swiss study cohorts (61% HCV genotype 1, 39% genotypes 2 or 3). Patients were analyzed for SLC28A2 single nucleotide polymorphism (SNP) rs11854484, SLC28A3 rs56350726, and SLC28A3 rs10868138 as well as ITPA SNPs rs1127354 and rs7270101, and followed for treatment-associated hemoglobin changes and sustained virological response (SVR). In 67 patients, RBV serum levels were additionally measured during treatment. RESULTS: Patients with SLC28A2 rs11854484 genotype TT had higher dosage- and body weight-adjusted RBV levels than those with genotypes TC or CC (p=0.02 and p=0.06 at weeks 4 and 8, respectively). ITPA SNP rs1127354 was associated with hemoglobin drop ≥3 g/dl during treatment, in genotype (relative risk (RR)=2.1, 95% CI 1.3-3.5) as well as allelic analyses (RR=2.0, 95%CI 1.2-3.4). SLC28A3 rs56350726 was associated with SVR in genotype (RR=2.2; 95% CI 1.1-4.3) as well as allelic analyses (RR=2.0, 95% CI 1.1-3.4). CONCLUSIONS: The newly identified association between RBV serum levels and SLC28A2 rs11854484 genotype, as well as the replicated association of ITPA and SLC28A3 genetic polymorphisms with RBV-induced anemia and treatment response, may support individualized treatment of chronic hepatitis C and warrant further investigation in larger studies.