Increased Muscle Stress-Sensitivity Induced by Selenoprotein N Inactivation in Mouse: A Mammalian Model for SEPN1-Related Myopathy

Selenium is an essential trace element and selenoprotein N (SelN) was the first selenium-containing protein shown to be directly involved in human inherited diseases. Mutations in the SEPN1 gene, encoding SelN, cause a group of muscular disorders characterized by predominant affection of axial muscles. SelN has been shown to participate in calcium and redox homeostasis, but its pathophysiological role in skeletal muscle remains largely unknown. To address SelN function in vivo, we generated a Sepn1-null mouse model by gene targeting. The Sepn1−/− mice had normal growth and lifespan, and were macroscopically indistinguishable from wild-type littermates. Only minor defects were observed in muscle morphology and contractile properties in SelN-deficient mice in basal conditions. However, when subjected to challenging physical exercise and stress conditions (forced swimming test), Sepn1−/− mice developed an obvious phenotype, characterized by limited motility and body rigidity during the swimming session, as well as a progressive curvature of the spine and predominant alteration of paravertebral muscles. This induced phenotype recapitulates the distribution of muscle involvement in patients with SEPN1-Related Myopathy, hence positioning this new animal model as a valuable tool to dissect the role of SelN in muscle function and to characterize the pathophysiological process

Regulation of microRNA biogenesis and turnover by animals and their viruses

Item does not contain fulltextMicroRNAs (miRNAs) are a ubiquitous component of gene regulatory networks that modulate the precise amounts of proteins expressed in a cell. Despite their small size, miRNA genes contain various recognition elements that enable specificity in when, where and to what extent they are expressed. The importance of precise control of miRNA expression is underscored by functional studies in model organisms and by the association between miRNA mis-expression and disease. In the last decade, identification of the pathways by which miRNAs are produced, matured and turned-over has revealed many aspects of their biogenesis that are subject to regulation. Studies in viral systems have revealed a range of mechanisms by which viruses target these pathways through viral proteins or non-coding RNAs in order to regulate cellular gene expression. In parallel, a field of study has evolved around the activation and suppression of antiviral RNA interference (RNAi) by viruses. Virus encoded suppressors of RNAi can impact miRNA biogenesis in cases where miRNA and small interfering RNA pathways converge. Here we review the literature on the mechanisms by which miRNA biogenesis and turnover are regulated in animals and the diverse strategies that viruses use to subvert or inhibit these processes

Which patient-related factors determine self-perceived patient adherence to prescribed dyspepsia medication?

Contains fulltext : 79835.pdf (publisher's version ) (Closed access)Patient adherence to medical treatment for dyspepsia is disappointing, whereas adherence is crucial for a proper evaluation of treatment. This prospective study used elements of the Integrated Change Model and Weiner's Attribution Theory to describe patients' important cognitions and their interrelationships regarding self-perceived adherence to short-term medical treatment for dyspepsia. Patient questionnaires measured the predictors before treatment and self-perceived adherence after treatment. Approximately one-quarter of the patients indicated that they were non-adherent (n = 347). Univariate and multiple linear regression analyses revealed several significant predictors that explained 44% of the variance in self-perceived adherence. Patients with a low educational level, patients who claimed to regularly forget their medication in general, patients with a low self-efficacy or a low intention were less likely to be adherent. These results may indicate targets for interventions designed to improve adherence to medical treatment for dyspepsia. For instance, asking about expected difficulties in taking acid suppressants (e.g. forgetfulness or medication use at weekends) and making action plans to overcome these difficulties (e.g. using reminders) may result in improved adherence rates. Such an approach may reach a substantial number of patients since one in five patients in our study experienced some difficulties in taking medication