Gene transfer engineering for astrocyte-specific silencing in the CNS.

Cell-type-specific gene silencing is critical to understand cell functions in normal and pathological conditions, in particular in the brain where strong cellular heterogeneity exists. Molecular engineering of lentiviral vectors has been widely used to express genes of interest specifically in neurons or astrocytes. However, we show that these strategies are not suitable for astrocyte-specific gene silencing due to the processing of small hairpin RNA (shRNA) in a cell. Here we develop an indirect method based on a tetracycline-regulated system to fully restrict shRNA expression to astrocytes. The combination of Mokola-G envelope pseudotyping, glutamine synthetase promoter and two distinct microRNA target sequences provides a powerful tool for efficient and cell-type-specific gene silencing in the central nervous system. We anticipate our vector will be a potent and versatile system to improve the targeting of cell populations for fundamental as well as therapeutic applications

Lentiviral vectors as tools to understand central nervous system biology in mammalian model organisms

Lentiviruses have been extensively used as gene delivery vectors since the mid-1990s. Usually derived from the human immunodeficiency virus genome, they mediate efficient gene transfer to non-dividing cells, including neurons and glia in the adult mammalian brain. In addition, integration of the recombinant lentiviral construct into the host genome provides permanent expression, including the progeny of dividing neural precursors. In this review, we describe targeted vectors with modified envelope glycoproteins and expression of transgenes under the regulation of cell-selective and inducible promoters. This technology has broad utility to address fundamental questions in neuroscience and we outline how this has been used in rodents and primates. Combining viral tract tracing with immunohistochemistry and confocal or electron microscopy, lentiviral vectors provide a tool to selectively label and trace specific neuronal populations at gross or ultrastructural levels. Additionally, new generation optogenetic technologies can be readily utilized to analyze neuronal circuit and gene functions in the mature mammalian brain. Examples of these applications, limitations of current systems and prospects for future developments to enhance neuroscience knowledge will be reviewed. Finally, we will discuss how these vectors may be translated from gene therapy trials into the clinical setting

Lentiviral vectors in Huntington's disease research and therapy

We describe here the potential of viral-mediated gene transfer for the modeling and treatment of Huntington's disease, focusing in particular on strategies for the tissue-specific targeting of various CNS cells. The protocols described here cover the design of lentiviral vectors, strategies for modifying their tropism, including the use of various envelopes and tissue-specific promoters, and the potential of miRNA to regulate transgene expression

Lentiviral vectors: a powerful tool to target astrocytes in vivo.

The morphological and functional diversity of astrocytes, and their essential contribution in physiological and pathological conditions, are starting to emerge. However, experimental systems to investigate neuron-glia interactions and develop innovative approaches for the treatment of central nervous system (CNS) disorders are still very limited. Fluorescent reporter genes have been used to visualize populations of astrocytes and produce an atlas of gene expression in the brain. Knock-down or knock-out of astrocytic proteins using transgenesis have also been developed, but these techniques remain complex and time-consuming. Viral vectors have been developed to overexpress or silence genes of interest as they can be used for both in vitro and in vivo studies in adult mammalian species. In most cases, high transduction efficiency and long-term transgene expression are observed in neurons but there is limited expression in astrocytes. Several strategies have been developed to shift the tropism of lentiviral vectors (LV) and allow local and controlled gene expression in glial cells. In this review, we describe how modifications of the interaction between the LV envelope glycoprotein and the surface receptor molecules on target cells, or the integration of cell-specific promoters and miRNA post-transcriptional regulatory elements have been used to selectively express transgenes in astrocytes

BMAALS: A French national project searching for a link between amyotrophic lateral sclerosis and the neurotoxic amino acid L-BMAA.

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First cases of calcium pyrophosphate deposition disease after zoledronic acid therapy

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Incidence de la sclérose latérale amyotrophique en limousin (2000–2011) : résultats du premier registre français des cas de SLA (registre FRALIM)

International audienceIntroductionL’incidence européenne de la sclérose latérale amyotrophique (SLA) est environ de 2,5/100 000 personnes-années (PA).ObjectifsÉvaluer l’incidence de la SLA en Limousin, sur une période de 12 ans (2000–2011) au travers d’un registre en population établi dans cette région.MéthodesLes patients vivant en Limousin au diagnostic de SLA selon les critères révisés de El Escorial, ont été inclus. Trois sources ont été utilisées : la base de données de la coordination nationale française des centres experts SLA ; les hôpitaux publics et privés ; les données d’assurance maladie relatives à l’ALD9. L’exhaustivité du registre a été estimée par la méthode capture-recapture. Le traitement des données a été autorisé par le CCTIRS et la CNIL.RésultatsLes incidences brute et standardisée sur la population européenne de 2010, étaient de 3,19/100 000 PA, (IC95 % 2,81–3,56) et 2,58/100 000 PA (IC95 % 2,27–2,89) respectivement. L’âge médian au diagnostic est de 70,8 ans (IQR 63,1-77,1). Le sex-ratio était de 1,3, mais de 1,1 chez les moins de 65 ans, de 1,7 entre 65 et 75 ans et de 1,9 chez les plus de 75 ans. L’exhaustivité du registre a été estimée à 98,4 % (IC95 % 95,6–99,4).DiscussionIl s’agit des résultats du premier registre SLA français. L’incidence brute est la plus élevée rapportée en Europe (et supérieure à celle des États-Unis). L’incidence standardisée fait également partie des plus fortes incidences décrites à ce jour. L’exhaustivité du registre est excellente.ConclusionLe registre constitue un cadre méthodologique fiable pour poursuivre des travaux de recherche dans ce domaine. Une extension géographique de ce registre est en cours

Incidence de la Sclérose Latérale Amyotrophique (SLA) en Limousin (2000-2011) : résultats du premier registre français des cas de SLA (Registre Fralim)

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Population based epidemiology of amyotrophic lateral sclerosis using capture-recapture methodology

Item does not contain fulltextBACKGROUND: Variation in the incidence rate in epidemiological studies on amyotrophic lateral sclerosis (ALS) may be due to a small population size and under ascertainment of patients. The previously reported incidence decline in the elderly and a decrease in the male:female ratio in postmenopausal age groups have yet to be confirmed. METHODS: ALS epidemiology in a large population based register in The Netherlands was studied between 1 January 2006 and 31 December 2009, and applied capture-recapture methodology in separate age and gender groups to adjust for the number of unobserved patients. RESULTS: 1217 incident patients were observed, and a capture-recapture incidence of 2.77 per 100 000 person-years (95% CI 2.63 to 2.91). Prevalence on 31 December 2008 was 10.32 per 100 000 individuals (95% CI 9.78 to 10.86). The incident cohort had a higher median age at onset (63.0 vs 58.1 years) and more bulbar onset patients (30.0% vs 19.1%) compared with the prevalent cohort. Incidence and prevalence peaked in the 70-74 year age group followed by a rapid decline in older age. The male:female ratio in the premenopausal age group (1.91, 95% CI 1.32 to 2.79) was not significantly higher than that in the postmenopausal age group (1.50, 95% CI 1.34 to 1.67). CONCLUSION: The marked difference in patient characteristics between incident and prevalent cohorts underscores the importance of including incident patients when studying susceptibility or disease modifying factors in ALS. The incidence decline in the elderly may suggest that ALS is not merely the result of ageing. Absence of a significant postmenopausal drop in the male:female ratio suggests that the protective role of female sex hormones in ALS is limited