Skeletal Muscle Biopsy Analysis in Reducing Body Myopathy and Other Fhl1-related Disorders

FHL1 mutations have been associated with various disorders that include reducing body myopathy (RBM), Emery-Dreifuss-like muscular dystrophy, isolated hypertrophic cardiomyopathy, and some overlapping conditions. We report a detailed histochemical, immunohistochemical, electron microscopic, and immunoelectron microscopic analyses of muscle biopsies from 18 patients carrying mutations in FHL1: 14 RBM patients (Group 1), 3 Emery-Dreifuss muscular dystrophy patients (Group 2), and 1 patient with hypertrophic cardiomyopathy and muscular hypertrophy (Group 2). Group 1 muscle biopsies consistently showed RBs associated with cytoplasmic bodies. The RBs showed prominent FHL1 immunoreactivity whereas desmin, alpha B-crystallin, and myotilin immunoreactivity surrounded RBs. By electron microscopy, RBs were composed of electron-dense tubulofilamentous material that seemed to spread progressively between the myofibrils and around myonuclei. By immunoelectron microscopy, FHL1 protein was found exclusively inside RBs. Group 2 biopsies showed mild dystrophic abnormalities without RBs; only minor nonspecific myofibrillar abnormalities were observed under electron microscopy. Molecular analysis revealed missense mutations in the second FHL1 LIM domain in Group 1 patients and ins/del or missense mutations within the fourth FHL1 LIM domain in Group 2 patients. Our findings expand the morphologic features of RBM, clearly demonstrate the localization of FHL1 in RBs, and further illustrate major morphologic differences among different FHL1-related myopathies

Intermédiation financière française et intermédiation financière ouest-allemande : perspectives pour une réforme

[eng] What about the french banking nationalization and how has it been turning out ? Had we or have we to expect from it a whole change of the french modern banking ? The question is not interesting since such a recasting is now necessity. The model to be regarded with has to be drawn from german financial institutions.. The purpose of the article lies in explaining why so, after having precised. — the state of the french interbanking connection and the result of it,. — the ways and means of the german banking system,. — and the adequation of the last one to the objects of the french planification.. It is a fact that the west german authorities have succeeded in diverting their credits and bank loans from the factors of the inflation, without having to apply any credit ceilings as it has been done in all other european countries and consequently to bear the perverse effect of it.. But does not the recent cutting out of the credit ceilings involve in a financial reform towards the way suggested ? And has not such a reform already begun with the certificates of deposit more recently instituted in France ?. The author of the published study precises the stake of that plan. He sets up the inventory of the means to be used, of the advantages involved in it and the limits of its own application. [fre] Qu'advient-il ou peut-il advenir de la nationalisation — encore récente — du crédit en France ? Fallait-il ou faut-il en attendre une réforme générale des structures bancaires elles-mêmes ? Peu importe dès lors que la nécessité s'en fait jour ainsi qu'il résulte du bilan de l'intermédiation ouest-allemande et de l'intérêt que présenterait la transposition de celle-ci dans les institutions françaises.. Tel est l'objet de cet article qui consiste à préciser.. • l'état et les conséquences de l'intermédiation française,. • les voies et les moyens de l'intermédiation allemande,. • et l'adéquation de cette dernière aux objectifs de la planification française.. C'est un fait que les autorités ouest-allemande ont réussi à dissocier leur crédit des sources de l'inflation sans avoir jamais eu à recourir au plafonnement du crédit ni à en subir les effets pervers qui ont constitué l'héritage le plus sûr de l'expérience française.. Mais la toute récente suppression du plafonnement des crédits en France n'implique-t-elle pas une réforme du genre de celle suggérée ? Et cette réforme n'est-elle pas déjà commencée à partir de la plus récente encore institution des certificats de dépôt ?. C'est l'inventaire d'une telle orientation, des moyens qu'elle suppose, des avantages qu'elle promet et des limites qu'elle comporte que tente de dresser l'auteur de l'étude publiée.

Therapy for Dominant Inherited Diseases by Allele-Specific RNA Interference: Successes and Pitfalls

International audienceRNA interference (RNAi) is a conserved mechanism for post-transcriptional gene silencing mediated by messenger RNA (mRNA) degradation. RNAi is commonly induced by synthetic siRNA or shRNA which recognizes the targeted mRNA by base pairing and leads to target-mRNA degradation. RNAi may discriminate between two sequences only differing by one nucleotide conferring a high specificity of RNAi for its target mRNA. This property was used to develop a particular therapeutic strategy called “allele-specific-RNA interference” devoted to silence the mutated allele of genes causing dominant inherited diseases without affecting the normal allele. Therapeutic benefit was now demonstrated in cells from patients and animal models, and promising results of the first phase Ib clinical trial using siRNA-based allele-specific therapy were reported in Pachyonychia Congenita, an inherited skin disorder due to dominant mutations in the Keratin 6 gene. Our purpose is to review the successes of this strategy aiming to treat dominant inherited diseases and to highlight the pitfalls to avoid

Dynamin 2 and human diseases

International audienceDynamin 2 (DNM2) mutations cause autosomal dominant centronuclear myopathy (CNM), a rare form of congenital myopathy, and intermediate and axonal forms of Charcot-Marie-Tooth disease (CMT), a peripheral neuropathy. DNM2 is a large GTPase mainly involved in membrane trafficking through its function in the formation and release of nascent vesicles from biological membranes. DNM2 participates in clathrin-dependent and clathrin-independent endocytosis and intracellular membrane trafficking (from endosomes and Golgi apparatus). Recent studies have also implicated DNM2 in exocytosis. DNM2 belongs to the machinery responsible for the formation of vesicles and regulates the cytoskeleton providing intracellular vesicle transport. In addition, DNM2 tightly interacts with, and is involved in the regulation of actin and microtubule networks, independent from membrane trafficking processes. We summarize here the molecular, biochemical and functional data on DNM2 and discuss the possible pathophysiological mechanisms via which DNM2 mutations can lead to two distinct neuromuscular disorders

Reprogramming the Dynamin 2 mRNA by Spliceosome-mediated RNA Trans-splicing

Dynamin 2 (DNM2) is a large GTPase, ubiquitously expressed, involved in membrane trafficking and regulation of actin and microtubule cytoskeletons. DNM2 mutations cause autosomal dominant centronuclear myopathy which is a rare congenital myopathy characterized by skeletal muscle weakness and histopathological features including nuclear centralization in absence of regeneration. No curative treatment is currently available for the DNM2-related autosomal dominant centronuclear myopathy. In order to develop therapeutic strategy, we evaluated here the potential of Spliceosome-Mediated RNA Trans-splicing technology to reprogram the Dnm2-mRNA in vitro and in vivo in mice. We show that classical 3′-trans-splicing strategy cannot be considered as accurate therapeutic strategy regarding toxicity of the pre-trans-splicing molecules leading to low rate of trans-splicing in vivo. Thus, we tested alternative strategies devoted to prevent this toxicity and enhance frequency of trans-splicing events. We succeeded to overcome the toxicity through a 5′-trans-splicing strategy which also allows detection of trans-splicing events at mRNA and protein levels in vitro and in vivo. These results suggest that the Spliceosome-Mediated RNA Trans-splicing strategy may be used to reprogram mutated Dnm2-mRNA but highlight the potential toxicity linked to the molecular tools which have to be carefully investigated during preclinical development

Nuclear defects in skeletal muscle from a Dynamin 2-linked centronuclear myopathy mouse model

Abstract Dynamin 2 (DNM2) is a key protein of the endocytosis and intracellular membrane trafficking machinery. Mutations in the DNM2 gene cause autosomal dominant centronuclear myopathy (CNM) and a knock-in mouse model expressing the most frequent human DNM2 mutation in CNM (Knock In-Dnm2 R465W/+) develops a myopathy sharing similarities with human disease. Using isolated muscle fibres from Knock In-Dnm2 R465W/+ mice, we investigated number, spatial distribution and morphology of myonuclei. We showed a reduction of nuclear number from 20 weeks of age in Tibialis anterior muscle from heterozygous mice. This reduction is associated with a decrease in the satellite cell content in heterozygous muscles. The concomitant reduction of myonuclei number and cross-section area in the heterozygous fibres contributes to largely maintain myonuclear density and volume of myonuclear domain. Moreover, we identified signs of impaired spatial nuclear distribution including alteration of distance from myonuclei to their nearest neighbours and change in orientation of the nuclei. This study highlights reduction of number of myonuclei, a key regulator of the myofiber size, as a new pathomechanism underlying muscle atrophy in the dominant centronuclear myopathy. In addition, this study opens a new line of investigation which could prove particularly important on satellite cells in dominant centronuclear myopathy

A new Centronuclear Myopathy phenotype due to a novel Dynamin 2 mutation

International audienc

A novel mutation in the dynamin 2 gene in a Charcot-Marie-Tooth type 2 patient: Clinical and pathological findings

International audienceMutations in dynamin 2 (DNM2) have been associated with autosomal dominant centronuclear myopathy, dominant intermediate Charcot-Marie-Tooth (CMT) type B and CMT2. Here, we report a novel DNM2 mutation in the Pleckstrin homology domain of DNM2 (p.K559del) in a patient with an axonal length-dependent sensorimotor polyneuropathy predominantly affecting the lower limbs. Neuropathy is associated with congenital cataracts, ophthalmoparesis, ptosis and neutropenia. There was no evidence of a skeletal myopathy on EMG or muscle biopsy. We suggest that this constellation of clinical features can help the diagnosis and selection of patients for direct DNM2 genetic analysis