Hybridase activity of human ribonuclease-1 revealed by a real-time fluorometric assay

Human ribonuclease-1 (hRNase-1) is an extracellular enzyme found in exocrine pancreas, blood, milk, saliva, urine and seminal plasma, which has been implicated in digestion of dietary RNA and in antiviral host defense. The enzyme is characterized by a high catalytic activity toward both single-stranded and double-stranded RNA. In this study, we explored the possibility that hRNase-1 may also be provided with a ribonuclease H activity, i.e. be able to digest the RNA component of RNA:DNA hybrids. For this purpose, we developed an accurate and sensitive real-time RNase H assay based on a fluorogenic substrate made of a 12 nt 5′-fluorescein-labeled RNA hybridized to a complementary 3′-quencher-modified DNA. Under physiological-like conditions, hRNase-1 was found to cleave the RNA:DNA hybrid very efficiently, as expressed by a k(cat)/K(m) of 330 000 M(−1) s(−1), a value that is over 180-fold higher than that obtained with the homologous bovine RNase A and only 8-fold lower than that measured with Escherichia coli RNase H. The kinetic characterization of hRNase-1 showed that its hybridase activity is maximal at neutral pH, increases with lowering ionic strength and is fully inhibited by the cytosolic RNase inhibitor. Overall, the reported data widen our knowledge of the enzymatic properties of hRNase-1 and provide new elements for the comprehension of its biological function

miRNAs as serum biomarkers for Duchenne muscular dystrophy

Dystrophin absence in Duchenne muscular dystrophy (DMD) causes severe muscle degeneration. We describe that, as consequence of fibre damage, specific muscle-miRNAs are released in to the bloodstream of DMD patients and their levels correlate with the severity of the disease. The same miRNAs are abundant also in the blood of mdx mice and recover to wild-type levels in animals ‘cured’ through exon skipping. Even though creatine kinase (CK) blood levels have been utilized as diagnostic markers of several neuromuscular diseases, including DMD, we demonstrate that they correlate less well with the disease severity. Although the analysis of a larger number of patients should allow to obtain more refined correlations with the different stages of disease progression, we propose that miR-1, miR-133, and miR-206 are new and valuable biomarkers for the diagnosis of DMD and possibly also for monitoring the outcomes of therapeutic interventions in humans. Despite many different DMD therapeutic approaches are now entering clinical trials, a unifying method for assessing the benefit of different treatments is still lacking

Nutrition and IBD: Malnutrition and/or Sarcopenia? A Practical Guide

Malnutrition is a major complication of inflammatory bowel disease (IBD). This mini review is focusing on main determinants of malnutrition in IBD, the most important components of malnutrition, including lean mass loss and sarcopenia, as an emerging problem. Each one of these components needs to be well considered in a correct nutritional evaluation of an IBD patient in order to build a correct multidisciplinary approach. The review is then focusing on possible instrumental and clinical armamentarium for the nutritional evaluation

26th Annual Computational Neuroscience Meeting (CNS*2017): Part 3 - Meeting Abstracts - Antwerp, Belgium. 15–20 July 2017

This work was produced as part of the activities of FAPESP Research,\ud Disseminations and Innovation Center for Neuromathematics (grant\ud 2013/07699-0, S. Paulo Research Foundation). NLK is supported by a\ud FAPESP postdoctoral fellowship (grant 2016/03855-5). ACR is partially\ud supported by a CNPq fellowship (grant 306251/2014-0)

L'Acquedotto Ostiense. Ricostruzione dell'antico percorso tra immagini iconografiche e rinvenimenti archeologici

Agli inizi degli anni '90 del XX secolo, nella zona in prossimità del Casale di Malafede, sono stati rinvenuti e portati alla luce in più punti le strutture di due condutture che correvano uniti e in direzione parallela, considerati appartenenti all'antico acquedotto Ostiense che riforniva la città di Ostia. Dai diversi rinvenimenti archeologici, avvenuti nel corso degli anni, é stato possibile stabilire la presenza di una complessa rete di approvvigionamento idrico che, alimentata dall'acquedotto Ostiense a partire dal fosso di Malafede, era funzionale sia all'uso agricolo sia a quello residenziale di tutto il territorio fino all' antica città di Ostia. Oggi tracce dell'antico acquedotto si possono scorgere lungo la via Ostiense, all'interno degli scavi dell'antica città di Ostia e nel circuito murario del Borgo rinascimentale, in cui vennero inglobate alcune arcate ancora oggi visibili sul lato orientale. Mediante l'analisi di fonti iconografiche, archivistiche e documentali, e rinvenimenti archeologici è possibile ricostruire il percorso dell'antico acquedotto e le interazioni con il tessuto urbano limitrofo

Michaelis–Menten plot for cleavage of the double-helical substrate by hRNase-1

<p><b>Copyright information:</b></p><p>Taken from "Hybridase activity of human ribonuclease-1 revealed by a real-time fluorometric assay"</p><p>Nucleic Acids Research 2006;34(10):2906-2913.</p><p>Published online 31 May 2006</p><p>PMCID:PMC1474055.</p><p>© The Author 2006. Published by Oxford University Press. All rights reserved</p> Assays were performed as detailed in , except that substrate concentration was 20–400 nM and enzyme concentration was 0.14–1.4 nM

MiR-31 modulates dystrophin expression: New implications for Duchenne muscular dystrophy therapy

Duchenne muscular dystrophy (DMD)--which is caused by mutations in the dystrophin gene-is one of the most severe myopathies. Among therapeutic strategies, exon skipping allows the rescue of dystrophin synthesis through the production of a shorter but functional messenger RNA. Here, we report the identification of a microRNA--miR-31--that represses dystrophin expression by targeting its 3' untranslated region. In human DMD myoblasts treated with exon skipping, we demonstrate that miR-31 inhibition increases dystrophin rescue. These results indicate that interfering with miR-31 activity can provide an ameliorating strategy for those DMD therapies that are aimed at efficiently recovering dystrophin synthesis

Association between hypermethylated tumor and paired surgical margins in head and neck squamous cell carcinomas

Abstract Purpose: Surgical margin status is reported to be a relevant prognostic factor in head and neck squamous cell carcinoma (HNSCC), associated with a high risk of local recurrence. This study examines whether gene-promoter hypermethylation could be detected in HNSCC surgical margins with no histologic evidence of malignancy, and if so, whether it reflects epigenetic events of primary tumors. Experimental Design: Promoter methylation status of MGMT, p16, and DAP-K genes was evaluated by methylation-specific PCR in 20 primary HNSCC tumors. Histopathologically negative surgical margins of hypermethylated tumors were collected, and their methylation status compared with the primary tumor status. Results: Promoter hypermethylation in at least one of the three tested genes was detected in 65% (13 of 20) of tumors. MGMT was hypermethylated in 50% (10 of 20), DAP-K in 45% (9 of 20), and p16 in 20% (4 of 20) of tumors. Methylation status was analyzed in 35 margins from 11 of 13 patients showing promoter hypermethylation in the tumor tissue. Identical methylation events were seen for at least one gene in primary tumor and surgical margins in 9 of 11 cases (82%). Association was found for gene-specific hypermethylation status in tumors and paired surgical margins, and gene-specific concordance was 63% for MGMT (κ = 0.24), 90% for DAP-K (κ = 0.74), and 90% for p16 (κ = 0.79). Conclusions: Our results support the hypothesis that detection of gene promoter hypermethylation in HNSCC tumor cells–free surgical margins may be a helpful biomarker to identify molecularly altered fields in areas adjacent to the tumor