Correction to: Use of MFM-20 to monitor SMA types 1 and 2 patients treated with nusinersen.

peer reviewe

Caractérisation moléculaire et biochimique des préphénate et arogénate déshydrogénases d'Arabidopsis thaliana, de synechocystis et de levure

L'arogénate deshydrogénase catalyse la réaction de décarboxylation oxydative de l'arogénate en tyrosine. Malgré l'importance de cette activité enzymatique chez les plantes, aucune arogénate déshydrogénase de plante n'avait été clonée ou purifiée au début de nos travaux. Notre étude a permis l'identification de deux gènes, notés tyrAAT1 et tyrAAT2, codant des arogénate deshydrogènase chez la plante modèle Arabidopsis thaliana. Une étude moléculaire et biochimique a montré que le produit du gène tyrAAT1 est constitué de domaines catalytiques très similaires et actifs séparément. Au contraire, le produit du gène tyrAAT2, comme toutes les préphénate et/ou arogénate deshydrogénases bactériennes actuellement identifiées n'est composé que par un seul domaine catalytique. L'étude de la localisation de ces deux isoformes chez Arabidopsis montre que ces deux gènes codent pour des enzymes plastidiales. Une étude biochimique réalisée à partir des protéines reombinantes TyrAAT1 et TyrAAT2 purifiées montre que les deux protéines possèdent des propriétés biochimiques proches et une étude in planta montre que les gènes tyrAAT1 et tyrAAT2 sont exprimés avec des abondances relatives proches dans tous les tissus étudiés.Une étude biochimique et structurale comparée entre les arogénate deshydrogénases d'Arabidopsis et de Synechocystis et la préphénate deshydrogénase de levure a été entreprise. Cette étude montre des mécanismes de régulation des enzymes différents permettant à ces organismes de mieux répondre aux besoins des cellules en acides aminés aromatiques. L'exploitation des connaissances acquises sur les activités préphénate et arogénate deshydrogénases a permis l'utilisation en transgenèse végétale de la préphénate deshydrogénase de levure afin de rendre les plantes tolérantes à des doses plus élevées en DKN.GRENOBLE1-BU Sciences (384212103) / SudocSudocFranceF

Engineering Plant Shikimate Pathway for Production of Tocotrienol and Improving Herbicide Resistance

Tocochromanols (tocopherols and tocotrienols), collectively known as vitamin E, are essential antioxidant components of both human and animal diets. Because of their potential health benefits, there is a considerable interest in plants with increased or customized vitamin E content. Here, we have explored a new strategy to reach this goal. In plants, phenylalanine is the precursor of a myriad of secondary compounds termed phenylpropanoids. In contrast, much less carbon is incorporated into tyrosine that provides p-hydroxyphenylpyruvate and homogentisate, the aromatic precursors of vitamin E. Therefore, we intended to increase the flux of these two compounds by deriving their synthesis directly at the level of prephenate. This was achieved by the expression of the yeast (Saccharomyces cerevisiae) prephenate dehydrogenase gene in tobacco (Nicotiana tabacum) plants that already overexpress the Arabidopsis p-hydroxyphenylpyruvate dioxygenase coding sequence. A massive accumulation of tocotrienols was observed in leaves. These molecules, which were undetectable in wild-type leaves, became the major forms of vitamin E in the leaves of the transgenic lines. An increased resistance of the transgenic plants toward the herbicidal p-hydroxyphenylpyruvate dioxygenase inhibitor diketonitril was also observed. This work demonstrates that the synthesis of p-hydroxyphenylpyruvate is a limiting step for the accumulation of vitamin E in plants

Tyrosine and Phenylalanine Are Synthesized within the Plastids in Arabidopsis1[W]

While the presence of a complete shikimate pathway within plant plastids is definitively established, the existence of a cytosolic postchorismate portion of the pathway is still debated. This question is alimented by the presence of a chorismate mutase (CM) within the cytosol. Until now, the only known destiny of prephenate, the product of CM, is incorporation into tyrosine (Tyr) and/or phenylalanine (Phe). Therefore, the presence of a cytosolic CM suggests that enzymes involved downstream of CM in Tyr or Phe biosynthesis could be present within the cytosol of plant cells. It was thus of particular interest to clarify the subcellular localization of arogenate dehydrogenases (TYRAs) and arogenate dehydratases (ADTs), which catalyze the ultimate steps in Tyr and Phe biosynthesis, respectively. The aim of this study was to address this question in Arabidopsis (Arabidopsis thaliana) by analysis of the subcellular localization of the two TYRAAts and the six AtADTs. This article excludes the occurrence of a spliced TYRAAt1 transcript encoding a cytosolic TYRA protein. Transient expression analyses of TYRA- and ADT-green fluorescent protein fusions reveal that the two Arabidopsis TYRA proteins and the six ADT proteins are all targeted within the plastid. Accordingly, TYRA and ADT proteins were both immunodetected in the chloroplast soluble protein fraction (stroma) of Arabidopsis. No TYRA or ADT proteins were immunodetected in the cytosol of Arabidopsis cells. Taken together, all our data exclude the possibility of Tyr and/or Phe synthesis within the cytosol, at least in green leaves and Arabidopsis cultured cells

L’évaluation automatisée et ludique de la fonction motrice : le projet Kinect MFM

National audienc

Distal motor function assessments of children with spinal muscular atrophy: the use of a tablets as a part of the proposed kinect-MFM study

International audienceIntroduction: Given the progress of research and management in the neuromuscular diseases, particularly in Spinal Muscular Atrophy (SMA), validated tools are needed to assess patients' motor function. These tools are fundamental in order to improve the understanding of the natural history and to quantify the impact of new therapeutics in these populations. The Motor Function Measure (MFM) is a validated scale for the measurement of functional motor capacities usable in all neuromuscular diseases. Purpose: Clinicians from a neuromuscular diseases reference center (Hospices Civils de Lyon, France) and G-SCOP research team (INP Grenoble, France) were developing the instrumented Kinect-MFM, an automated system to assess SMA patients' motor function using new and low cost technology. By using, these technologies, our objectives were to improve the quality and reproducibility of the MFM by suppressing subjectivity linked to heteroevaluation. Method: The first step of this work was to assess the relevance of the tablet to capture and measure distal motor functions during a MFM test. The second was to compare the scoring of MFM items provided by a therapist with the scoring provided by the system. Results: Three applications were developed on this system to allow the comparison. They show difficulties to reproduce exactly the same conditions than in the current MFM. The size, the sensitivity, the multipoint control and the accuracy of the tablet constitute some challenge we have to take up. Conclusions: the proposed tablet was initially user to control the complete system by the therapist. The complexity of measuring distal functions by the Kinect led us to use this technology to complete the MFM instrumented protocol researchers proposed

L’évaluation automatisée et ludique de la fonction motrice : le projet Kinect MFM

National audienc

The Lived Experience of Pediatric Gene Therapy Clinical Trial in Duchenne Muscular Dystrophy: Exploring Perceptions of Parents and Professionals Using Social Representation Method.

International audienceIn recent decades, medical and scientific advances have led to the development of new therapeutic approaches for Duchenne muscular dystrophy (DMD), including gene therapy (GT), which is currently being evaluated. Recruiting enough children in clinical trials remains a challenge, depending on parental decisions. Numerous studies have already been carried out to understand these decision-making factors. To date, no study in Europe has been conducted among the various stakeholders lived experience in a DMD GT trial. Our qualitative study explored participants' perceptions using a social representation method and compared them. We recruited 42 participants, divided into 2 groups comprising 21 parents and 21 professionals participating in GNT-014, a DMD natural history study. Each participant was interviewed on four questions about clinical trials, GT, and the facilitators and barriers of the clinical trial pathway. A prototypical and categorical analysis was carried out using "Pointe-au-Sel" software to analyze the data quantitatively. This method highlights which perceptions are shared within the same group and brings out the most important and most frequently evoked terms. We exported the data as a superimposed scatterplot of the representations of both groups for each question. We obtained a total of 453 evocations for the parents' group and a total of 611 evocations for the professionals' group. For clinical trial and GT, hope and scientific progress are common to the core of both groups but are not at the same level of representation. Parents evoked human contact as the main facilitator and what their child may undergo and become for barriers. For professionals, the facilitators and barriers are centered on the terms that can influence the proper conduct of the trial. These comparative results imply that the vision of the different stakeholders is not totally shared in trial participation. On the contrary, the term GT may also have an influence on professionals, including caregivers

Is Going Beyond Rasch Analysis Necessary to Assess the Construct Validity of a Motor Function Scale?

International audienceObjectives: Micronutrient supplementation in critically ill adults remains controversial. In the pediatric setting, the impact of oxidative stress on the overall micronutrient status has been poorly explored, due to the limited number of studies and to confounding factors (i.e., malnutrition or extra losses). In order to better understand this phenomenon, we aim to describe micronutrient status, focusing on seven micronutrients, in well-nourished critically ill children presenting with severe oxidative stress. Design: Prospective, transversal, observational, single-center study. Setting: PICU, and anesthesiology department, Lyon, France. Patients: Three groups of patients were clinically defined: severe oxidative stress PICU group (at least two organ dysfunctions), moderate oxidative stress PICU group (single organ dysfunction), and healthy control group (prior to elective surgery); oxidative stress intensity was controlled by measuring plasma levels of glutathione peroxidase and glutathione. Children presenting any former condition leading to micronutrient deficiency were excluded (malnutrition, external losses). Interventions: Plasma levels of selenium, zinc, copper, vitamin A, vitamin E, vitamin C, and β-carotene were measured in PICU oxidative stress conditions and compared with those of healthy children. Measurements and Main Results: Two hundred one patients were enrolled (51, 48, and 102 in severe, moderate, and healthy control groups, respectively). Median age was 7.1 years (interquartile range, 2.1–13.8 yr). There was a significant trend ( p < 0.02) toward plasma level decrease of six micronutrients (selenium, zinc, copper, vitamin E, vitamin C, and β-carotene) while oxidative stress intensity increased. Biological markers of oxidative stress (glutathione peroxidase and glutathione) were in accordance with the clinical definition of the three groups. Conclusions: A multiple micronutrient deficiency or redistribution occurs in critically ill children presenting with severe oxidative stress. These findings will help to better identify children who might benefit from micronutrient supplementation and to design adapted supplementation trials in this particular setting