Influence of insulators on transgene expression from integrating and non-integrating lentiviral vectors.

International audienceBACKGROUND: The efficacy and biosafety of lentiviral gene transfer is influenced by the design of the vector. To this end, properties of lentiviral vectors can be modified by using cis-acting elements such as the modification of the U3 region of the LTR, the incorporation of the central flap (cPPT-CTS) element, or post-transcriptional regulatory elements such as the woodchuck post-transcriptional regulatory element (WPRE). Recently, several studies evaluated the influence of the incorporation of insulators into the integrating lentiviral vector genome on transgene expression level and position effects. METHODS: In the present study, the influence of the matrix attachment region (MAR) of the mouse immunoglobulin-κ (Ig-κ) or the chicken lysozyme (ChL) gene was studied on three types of HIV-1-derived lentiviral vectors: self-inactivating (SIN) lentiviral vectors (LV), double-copy lentiviral vectors (DC) and non-integrating lentiviral vectors (NILVs) in different cell types: HeLa, HEK293T, NIH-3T3, Raji, and T Jurkat cell lines and primary neural progenitors. RESULTS AND DISCUSSION: Our results demonstrate that the Ig-κ MAR in the context of LV slightly increases transduction efficiency only in Hela, NIH-3T3 and Jurkat cells. In the context of double-copy lentiviral vectors, the Ig-κ MAR has no effect or even negatively influences transduction efficiency. In the same way, in the context of non-integrating lentiviral vectors, the Ig-κ MAR has no effect or even negatively influences transduction efficiency, except in differentiated primary neural progenitor cells.The ChL MAR in the context of integrating and non-integrating lentiviral vectors shows no effect or a decrease of transgene expression in all tested conditions. CONCLUSIONS: This study demonstrates that MAR sequences not necessarily increase transgene expression and that the effect of these sequences is probably context dependent and/or vector dependent. Thus, this study highlights the importance to consider a MAR sequence in a given context. Moreover, other recent reports pointed out the potential effects of random integration of insulators on the expression level of endogenous genes. Taken together, these results show that the use of an insulator in a vector for gene therapy must be well assessed in the particular therapeutic context that it will be used for, and must be balanced with its potential genotoxic effects

Expanding the clinical spectrum of hereditary fibrosing poikiloderma with tendon contractures, myopathy and pulmonary fibrosis due to <i>FAM111B </i>mutations

BACKGROUND: Hereditary Fibrosing Poikiloderma (HFP) with tendon contractures, myopathy and pulmonary fibrosis (POIKTMP [MIM 615704]) is a very recently described entity of syndromic inherited poikiloderma. Previously by using whole exome sequencing in five families, we identified the causative gene, FAM111B (NM_198947.3), the function of which is still unknown. Our objective in this study was to better define the specific features of POIKTMP through a larger series of patients. METHODS: Clinical and molecular data of two families and eight independent sporadic cases, including six new cases, were collected. RESULTS: Key features consist of: (i) early-onset poikiloderma, hypotrichosis and hypohidrosis; (ii) multiple contractures, in particular triceps surae muscle contractures; (iii) diffuse progressive muscular weakness; (iv) pulmonary fibrosis in adulthood and (v) other features including exocrine pancreatic insufficiency, liver impairment and growth retardation. Muscle magnetic resonance imaging was informative and showed muscle atrophy and fatty infiltration. Histological examination of skeletal muscle revealed extensive fibroadipose tissue infiltration. Microscopy of the skin showed a scleroderma-like aspect with fibrosis and alterations of the elastic network. FAM111B gene analysis identified five different missense variants (two recurrent mutations were found respectively in three and four independent families). All the mutations were predicted to localize in the trypsin-like cysteine/serine peptidase domain of the protein. We suggest gain-of-function or dominant-negative mutations resulting in FAM111B enzymatic activity changes. CONCLUSIONS: HFP with tendon contractures, myopathy and pulmonary fibrosis, is a multisystemic disorder due to autosomal dominant FAM111B mutations. Future functional studies will help in understanding the specific pathological process of this fibrosing disorder

Genetic correlation between amyotrophic lateral sclerosis and schizophrenia

A. Palotie on työryhmän Schizophrenia Working Grp Psychiat jäsen.We have previously shown higher-than-expected rates of schizophrenia in relatives of patients with amyotrophic lateral sclerosis (ALS), suggesting an aetiological relationship between the diseases. Here, we investigate the genetic relationship between ALS and schizophrenia using genome-wide association study data from over 100,000 unique individuals. Using linkage disequilibrium score regression, we estimate the genetic correlation between ALS and schizophrenia to be 14.3% (7.05-21.6; P = 1 x 10(-4)) with schizophrenia polygenic risk scores explaining up to 0.12% of the variance in ALS (P = 8.4 x 10(-7)). A modest increase in comorbidity of ALS and schizophrenia is expected given these findings (odds ratio 1.08-1.26) but this would require very large studies to observe epidemiologically. We identify five potential novel ALS-associated loci using conditional false discovery rate analysis. It is likely that shared neurobiological mechanisms between these two disorders will engender novel hypotheses in future preclinical and clinical studies.Peer reviewe

Développement de vecteurs lentiviraux non-intégratifs en vue du transfert de gènes dans le système nerveux central

PARIS7-Bibliothèque centrale (751132105) / SudocSudocFranceF

Etude de la régulation de l'expression des gènes imbriqués codant la choline acétyltransferase et le transporteur vésiculaire de l'acétylcholine chez le rat

PARIS-BIUSJ-Thèses (751052125) / SudocPARIS-BIUSJ-Physique recherche (751052113) / SudocSudocFranceF

Un nouveau modèle pour étudier la physiopathologie des chondrodysplasies liées à la FGFR3

FGFR3 (Fibroblast Growth Factor Receptor 3) est responsable d'une famille de chondrodysplasies de sévérité variable regroupant l'hypochondroplasie, forme modérée, l'achondroplasie, nanisme le plus fréquent et le nanisme thanatophore, forme sévère. Afin de comprendre les conséquences des mutations activatrices sur le développement squelettique, un nouveau modèle murin a été généré exprimant une mutation de nanisme thanatophore. Les souris mutantes présentent un nanisme sévère évolutif avec des os longs courts et trapus, une plaque de croissance désorganisée et un retard d'ossification épiphysaire. De plus, des anomalies de l'épithélium sensoriel de la cochlée ont été mises en évidence et sont responsables d'une surdité chez la souris mutante. Parallèlement, une étude a été réalisée chez l'humain montrant également un retard d'âge osseux et une surdité neurosensorielle dans l'achondroplasie. Ces résultats confirment le rôle primordial de FGFR3 dans l'ossification enchondrale et l'audition.FGFR3 (Fibroblast Growth Factor Receptor 3) cause several chondrodysplasias, including hypochondroplasia, mild phenotype, achondroplasia, most common form of human dwarfism, and thanatophoric dysplasia, severe dwarfism. To investigate the role of activating FGFR3 mutation in skeletal development, we introduced fgfrS mutation in mouse genome corresponding to the thanatophoric dysplasia. The mutant mice displayed severe dwarfism with shortened long bones, growth plate disturbed and secondary ossification center delayed. In addition, the mutant mice exhibited mild deafness with defect in epithelial sensory cells of the inner ear. At the same time, a human study was performed: a bone age delay and a sensorineural hearing loss were also observed in achondroplasia patients. Our results demonstrate the crucial role of FGFRS in endochondral ossification and auditory system.PARIS5-BU Méd.Cochin (751142101) / SudocSudocFranceF

Genetic and floral variation in two colosely related Jumella spp. (Orchidaceae) in Mascarene Islands

International audienceno abstrac

Marine aerosol distribution and variability over the pristine Southern Indian Ocean

International audienceThis paper presents an 8-year (2005–2012 inclusive) study of the marine aerosol distribution and variability over the Southern Indian Ocean, precisely in the areaa {10° S−40° S ; 50° E−110° E} which has been identified as one of the most pristine regions of the globe. A large dataset consisting of satellite data (POLDER, CALIOP), AERONET measurements at Saint-Denis (French Réunion Island) and model reanalysis (MACC), has been used. In spite of a positive bias of about 0.05 between the AOD (aerosol optical depth) given by POLDER and MACC on one hand and the AOD measured by AERONET on the other, consistent results for aerosol distribution and variability over the area considered have been obtained. First, aerosols are mainly confined below 2 km asl (above sea level) and are dominated by sea salt, especially in the center of the area of interest, with ≤ AOD 0. 1. This zone is the most pristine and is associated with the position of the Mascarene anticyclone. There, the direct radiative effect is assessed around − 9 W m^-2 at the top of the atmosphere and probability density functions of the AODs are leptokurtic lognormal functions without any significant seasonal variation. It is also suggested that the Madden-Jullian oscillation impacts sea salt emissions in the northern part of the area considered by modifying the state of the ocean surface. Finally, this area is surrounded in the northeast and the southwest by seasonal Australian and South African intrusions AOD > 0. 1); throughout the year, the ITCZ seems to limit continental contaminations from Asia. Due to the long period of time considered (almost a decade), this paper completes and strengthens results of studies based on observations performed during previous specific field campaigns