Sivilisaatioiden sodat, kulttuurikamppailut ja antiglobalismi Osa I

Abstract

Allele-specific silencing of mutant huntingtin in rodent brain and human stem cells.

Huntington's disease (HD) is an autosomal dominant neurodegenerative disorder resulting from polyglutamine expansion in the huntingtin (HTT) protein and for which there is no cure. Although suppression of both wild type and mutant HTT expression by RNA interference is a promising therapeutic strategy, a selective silencing of mutant HTT represents the safest approach preserving WT HTT expression and functions. We developed small hairpin RNAs (shRNAs) targeting single nucleotide polymorphisms (SNP) present in the HTT gene to selectively target the disease HTT isoform. Most of these shRNAs silenced, efficiently and selectively, mutant HTT in vitro. Lentiviral-mediated infection with the shRNAs led to selective degradation of mutant HTT mRNA and prevented the apparition of neuropathology in HD rat's striatum expressing mutant HTT containing the various SNPs. In transgenic BACHD mice, the mutant HTT allele was also silenced by this approach, further demonstrating the potential for allele-specific silencing. Finally, the allele-specific silencing of mutant HTT in human embryonic stem cells was accompanied by functional recovery of the vesicular transport of BDNF along microtubules. These findings provide evidence of the therapeutic potential of allele-specific RNA interference for HD.

Mechanistic insights into cytosolic molecular chaperones in protein unfolding and disaggregation

Under optimal non-physiological conditions of low concentrations and low temperatures, proteins may spontaneously fold to the native state, as all the information for folding lies in the amino acid sequence of the polypeptide. However, under conditions of stress or high protein crowding as inside cells, a polypeptide may misfold and enter an aggregation pathway resulting in the formation of misfolded conformers and fibrils, which can be toxic and lead to neurodegenerative illnesses, such as Alzheimer's, Parkinson's or Huntington's diseases and aging in general. To avert and revert protein misfolding and aggregation, cells have evolved a set of proteins called molecular chaperones. Here, I focussed on the human cytosolic chaperones Hsp70 (DnaK) and HspllO, and co-chaperone Hsp40 (DnaJ), and the chaperonin CCT (GroEL). The cytosolic molecular chaperones Hsp70s/Hspll0s and the chaperonins are highly upregulated in bacterial and human cells under different stresses and are involved both in the prevention and the reversion of protein misfolding and aggregation. Hsp70 works in collaboration with Hsp40 to reactivate misfolded or aggregated proteins in a strict ATP dependent manner. Chaperonins (CCT and GroEL) also unfold and reactivate stably misfolded proteins but we found that it needed to use the energy of ATP hydrolysis in order to evict over- sticky misfolded intermediates that inhibited the unfoldase catalytic sites. Ill In this study, we initially characterized a particular type of inactive misfolded monomeric luciferase and rhodanese species that were obtained by repeated cycles of freeze-thawing (FT). These stable misfolded monomeric conformers (FT-luciferase and FT-rhodanese) had exposed hydrophobic residues and were enriched with wrong ß-sheet structures (Chapter 2). Using FT-luciferase as substrate, we found that the Hsp70 orthologs, called HspllO (Sse in yeast), acted similarly to Hsp70 as were bona fide ATP- fuelled polypeptide unfoldases and was much more than a mere nucleotide exchange factor, as generally thought. Moreover, we found that HspllO collaborated with Hsp70 in the disaggregation of stable protein aggregates in which Hsp70 and HspllO acted as equal partners that synergistically combined their individual ATP-consuming polypeptide unfoldase activities to reactivate the misfolded/aggregated proteins (Chapter 3). Using FT-rhodanese as substrate, we found that chaperonins (GroEL and CCT) could catalytically reactivate misfolded rhodanese monomers in the absence of ATP. Also, our results suggested that encaging of an unfolding polypeptide inside the GroEL cavity under a GroES cap was not an obligatory step as generally thought (Chapter 4). Further, we investigated the role of Hsp40, a J-protein co-chaperone of Hsp70, in targeting misfolded polypeptides substrates onto Hsp70 for unfolding. We found that even a large excess of monomeric unfolded a-synuclein did not inhibit DnaJ, whereas, in contrast, stable misfolded a-synuclein oligomers strongly inhibited the DnaK-mediated chaperone reaction by way of sequestering the DnaJ co-chaperone. This work revealed that DnaJ could specifically distinguish, and bind potentially toxic stably aggregated species, such as soluble a-synuclein oligomers involved in Parkinson's disease, and with the help of DnaK and ATP convert them into from harmless natively unfolded a-synuclein monomers (chapter 5). Finally, our meta-analysis of microarray data of plant and animal tissues treated with various chemicals and abiotic stresses, revealed possible co-expressions between core chaperone machineries and their co-chaperone regulators. It clearly showed that protein misfolding in the cytosol elicits a different response, consisting of upregulating the synthesis mainly of cytosolic chaperones, from protein misfolding in the endoplasmic reticulum (ER) that elicited a typical unfolded protein response (UPR), consisting of upregulating the synthesis mainly of ER chaperones. We proposed that drugs that best mimicked heat or UPR stress at increasing the chaperone load in the cytoplasm or ER respectively, may prove effective at combating protein misfolding diseases and aging (Chapter 6).  - Dans les conditions optimales de basse concentration et de basse température, les protéines vont spontanément adopter un repliement natif car toutes les informations nécessaires se trouvent dans la séquence des acides aminés du polypeptide. En revanche, dans des conditions de stress ou de forte concentration des protéines comme à l'intérieur d'une cellule, un polypeptide peu mal se replier et entrer dans un processus d'agrégation conduisant à la formation de conformères et de fibrilles qui peuvent être toxiques et causer des maladies neurodégénératives comme la maladie d'Alzheimer, la maladie de Parkinson ou la chorée de Huntington. Afin d'empêcher ou de rectifier le mauvais repliement des protéines, les cellules ont développé des protéines appelées chaperonnes. Dans ce travail, je me suis intéressé aux chaperonnes cytosoliques Hsp70 (DnaK) et HspllO, la co-chaperones Hsp40 (DnaJ), le complexe CCT/TRiC et GroEL. Chez les bactéries et les humains, les chaperonnes cytosoliques Hsp70s/Hspl 10s et les « chaperonines» sont fortement activées par différentes conditions de stress et sont toutes impliquées dans la prévention et la correction du mauvais repliement des protéines et de leur agrégation. Hsp70 collabore avec Hsp40 pour réactiver les protéines agrégées ou mal repliées et leur action nécessite de 1ATP. Les chaperonines (GroEL) déplient et réactivent aussi les protéines mal repliées de façon stable mais nous avons trouvé qu'elles utilisent l'ATP pour libérer les intermédiaires collant et mal repliés du site catalytique de dépliage. Nous avons initialement caractérisé un type particulier de formes stables de luciférase et de rhodanese monomériques mal repliées obtenues après plusieurs cycles de congélation / décongélation répétés (FT). Ces monomères exposaient des résidus hydrophobiques et étaient plus riches en feuillets ß anormaux. Ils pouvaient cependant être réactivés par les chaperonnes Hsp70+Hsp40 (DnaK+DnaJ) et de l'ATP, ou par Hsp60 (GroEL) sans ATP (Chapitre 2). En utilisant la FT-Luciferase comme substrat nous avons trouvé que HspllO (un orthologue de Hsp70) était une authentique dépliase, dépendante strictement de l'ATP. De plus, nous avons trouvé que HspllO collaborait avec Hsp70 dans la désagrégation d'agrégats stables de protéines en combinant leurs activités dépliase consommatrice d'ATP (Chapitre 3). En utilisant la FT-rhodanese, nous avons trouvé que les chaperonines (GroEL et CCT) pouvaient réactiver catalytiquement des monomères mal repliés en absence d'ATP. Nos résultats suggérèrent également que la capture d'un polypeptide en cours de dépliement dans la cavité de GroEL et sous un couvercle du complexe GroES ne serait pas une étape obligatoire du mécanisme, comme il est communément accepté dans la littérature (Chapitre 4). De plus, nous avons étudié le rôle de Hsp40, une co-chaperones de Hsp70, dans l'adressage de substrats polypeptidiques mal repliés vers Hsp70. Ce travail a révélé que DnaJ pouvait différencier et lier des polypeptide mal repliés (toxiques), comme des oligomères d'a-synucléine dans la maladie de Parkinson, et clairement les différencier des monomères inoffensifs d'a-synucléine (Chapitre 5). Finalement une méta-analyse de données de microarrays de tissus végétaux et animaux traités avec différents stress chimiques et abiotiques a révélé une possible co-expression de la machinerie des chaperonnes et des régulateurs de co- chaperonne. Cette meta-analyse montre aussi clairement que le mauvais repliement des protéines dans le cytosol entraîne la synthèse de chaperonnes principalement cytosoliques alors que le mauvais repliement de protéines dans le réticulum endoplasmique (ER) entraine une réponse typique de dépliement (UPR) qui consiste principalement en la synthèse de chaperonnes localisées dans l'ER. Nous émettons l'hypothèse que les drogues qui reproduisent le mieux les stress de chaleur ou les stress UPR pourraient se montrer efficaces dans la lutte contre le mauvais repliement des protéines et le vieillissement (Chapitre 6).

The striatal long noncoding RNA Abhd11os is neuroprotective against an N-terminal fragment of mutant huntingtin in vivo.

A large number of gene products that are enriched in the striatum have ill-defined functions, although they may have key roles in age-dependent neurodegenerative diseases affecting the striatum, especially Huntington disease (HD). In the present study, we focused on Abhd11os, (called ABHD11-AS1 in human) which is a putative long noncoding RNA (lncRNA) whose expression is enriched in the mouse striatum. We confirm that despite the presence of 2 small open reading frames (ORFs) in its sequence, Abhd11os is not translated into a detectable peptide in living cells. We demonstrate that Abhd11os levels are markedly reduced in different mouse models of HD. We performed in vivo experiments in mice using lentiviral vectors encoding either Abhd11os or a small hairpin RNA targeting Abhd11os. Results show that Abhd11os overexpression produces neuroprotection against an N-terminal fragment of mutant huntingtin, whereas Abhd11os knockdown is protoxic. These novel results indicate that the loss lncRNA Abhd11os likely contribute to striatal vulnerability in HD. Our study emphasizes that lncRNA may play crucial roles in neurodegenerative diseases.

Longitudinal study of informed consent in innovative therapy research: experience and provisional recommendations from a multicenter trial of intracerebral grafting.

BACKGROUND: There is an urgent need to assess and improve the consent process in clinical trials of innovative therapies for neurodegenerative disorders. METHODS: We performed a longitudinal study of the consent of Huntington's disease patients during the Multicenter Fetal Cell Intracerebral Grafting Trial in Huntington's Disease (MIG-HD) in France and Belgium. Patients and their proxies completed a consent questionnaire at inclusion, before signing the consent form and after one year of follow-up, before randomization and transplantation. The questionnaire explored understanding of the protocol, satisfaction with the information delivered, reasons for participating in the trial and expectations regarding the transplant. Forty-six Huntington's disease patients and 27 proxies completed the questionnaire at inclusion, and 27 Huntington's disease patients and 16 proxies one year later. RESULTS: The comprehension score was high and similar for Huntington's disease patients and proxies at inclusion (72.6% vs 77.8%; P > 0.1) but only decreased in HD patients after one year. The information satisfaction score was high (73.5% vs 66.5%; P > 0.1) and correlated with understanding in both patients and proxies. The motivation and expectation profiles were similar in patients and proxies and remained unchanged after one year. CONCLUSIONS: Cognitively impaired patients with Huntington's disease were capable of consenting to participation in this trial. This consent procedure has presumably strengthened their understanding and should be proposed before signing the consent form in future gene or cell therapy trials for neurodegenerative disorders. Because of the potential cognitive decline, proxies should be designated as provisional surrogate decision-makers, even in competent patients.

The Role of Trade in the Structural Transformations of South Korea and the United Kingdom

[cat] El comerç internacional en béns agrícoles té el potencial d'accelerar la transformació estructural dels països amb baixa productivitat agrícola perquè els dóna la possiblitat d'importar aliments. L'objectiu d'aquest article és estudiar l'importància del comerç internacional en aquest context a través dels exemples de Corea del Sud i el Regne Unit. Per fer l'anàlisi, introdueixo comerç internacional en un model de creixement neoclàssicc amb dos sectors, agricultura i no-agricultura. Una característica clau del model és la baixa elasticitat-ingrés del bé agrícola.

The Role of Trade in the Structural Transformations of South Korea and the United Kingdom

[cat] El comerç internacional en béns agrícoles té el potencial d'accelerar la transformació estructural dels països amb baixa productivitat agrícola perquè els dóna la possiblitat d'importar aliments. L'objectiu d'aquest article és estudiar l'importància del comerç internacional en aquest context a través dels exemples de Corea del Sud i el Regne Unit. Per fer l'anàlisi, introdueixo comerç internacional en un model de creixement neoclàssicc amb dos sectors, agricultura i no-agricultura. Una característica clau del model és la baixa elasticitat-ingrés del bé agrícola.

Early Recurrence and Cerebral Bleeding in Patients With Acute Ischemic Stroke and Atrial Fibrillation: effect of Anticoagulation and Its Timing: the RAF Study.

BACKGROUND AND PURPOSE: The best time for administering anticoagulation therapy in acute cardioembolic stroke remains unclear. This prospective cohort study of patients with acute stroke and atrial fibrillation, evaluated (1) the risk of recurrent ischemic event and severe bleeding; (2) the risk factors for recurrence and bleeding; and (3) the risks of recurrence and bleeding associated with anticoagulant therapy and its starting time after the acute stroke. METHODS: The primary outcome of this multicenter study was the composite of stroke, transient ischemic attack, symptomatic systemic embolism, symptomatic cerebral bleeding and major extracranial bleeding within 90 days from acute stroke. RESULTS: Of the 1029 patients enrolled, 123 had 128 events (12.6%): 77 (7.6%) ischemic stroke or transient ischemic attack or systemic embolism, 37 (3.6%) symptomatic cerebral bleeding, and 14 (1.4%) major extracranial bleeding. At 90 days, 50% of the patients were either deceased or disabled (modified Rankin score ≥3), and 10.9% were deceased. High CHA2DS2-VASc score, high National Institutes of Health Stroke Scale, large ischemic lesion and type of anticoagulant were predictive factors for primary study outcome. At adjusted Cox regression analysis, initiating anticoagulants 4 to 14 days from stroke onset was associated with a significant reduction in primary study outcome, compared with initiating treatment before 4 or after 14 days: hazard ratio 0.53 (95% confidence interval 0.30-0.93). About 7% of the patients treated with oral anticoagulants alone had an outcome event compared with 16.8% and 12.3% of the patients treated with low molecular weight heparins alone or followed by oral anticoagulants, respectively (P=0.003). CONCLUSIONS: Acute stroke in atrial fibrillation patients is associated with high rates of ischemic recurrence and major bleeding at 90 days. This study has observed that high CHA2DS2-VASc score, high National Institutes of Health Stroke Scale, large ischemic lesions, and type of anticoagulant administered each independently led to a greater risk of recurrence and bleedings. Also, data showed that the best time for initiating anticoagulation treatment for secondary stroke prevention is 4 to 14 days from stroke onset. Moreover, patients treated with oral anticoagulants alone had better outcomes compared with patients treated with low molecular weight heparins alone or before oral anticoagulants.

Dominant-Negative Effects of Adult-Onset Huntingtin Mutations Alter the Division of Human Embryonic Stem Cells-Derived Neural Cells.

Mutations of the huntingtin protein (HTT) gene underlie both adult-onset and juvenile forms of Huntington's disease (HD). HTT modulates mitotic spindle orientation and cell fate in mouse cortical progenitors from the ventricular zone. Using human embryonic stem cells (hESC) characterized as carrying mutations associated with adult-onset disease during pre-implantation genetic diagnosis, we investigated the influence of human HTT and of an adult-onset HD mutation on mitotic spindle orientation in human neural stem cells (NSCs) derived from hESCs. The RNAi-mediated silencing of both HTT alleles in neural stem cells derived from hESCs disrupted spindle orientation and led to the mislocalization of dynein, the p150Glued subunit of dynactin and the large nuclear mitotic apparatus (NuMA) protein. We also investigated the effect of the adult-onset HD mutation on the role of HTT during spindle orientation in NSCs derived from HD-hESCs. By combining SNP-targeting allele-specific silencing and gain-of-function approaches, we showed that a 46-glutamine expansion in human HTT was sufficient for a dominant-negative effect on spindle orientation and changes in the distribution within the spindle pole and the cell cortex of dynein, p150Glued and NuMA in neural cells. Thus, neural derivatives of disease-specific human pluripotent stem cells constitute a relevant biological resource for exploring the impact of adult-onset HD mutations of the HTT gene on the division of neural progenitors, with potential applications in HD drug discovery targeting HTT-dynein-p150Glued complex interactions.

Per què França lidera la recerca científica pública?

A la llista Top 100 Global Innovators 2011 trobem 40 companyies dels Estats Units, 27 del Japó, 11 de França, 6 de Suècia, 4 d'Alemanya, 4 de Corea del Sud, 4 dels Països Baixos, 3 de Suïssa i 1 de Liechtenstein. Els Estats Units lideren la llista, hi ha més empreses asiàtiques que europees i cap de la Xina, que és líder en quantitat de patents però no en influència i qualitat

A ética na história do aconselhamento genético: um desafio à educação médica

O aconselhamento genético é uma prática que surgiu nos Estados Unidos na década de 1940 e tem se difundido ao redor do mundo com a crescente popularização da informação genética e a profissionalização da genética na saúde pública. É por meio de sessões de aconselhamento que as pessoas são informadas sobre os resultados de testes genéticos e recebem orientações sobre probabilidades, riscos e possibilidades de doenças genéticas. Trata-se de uma prática profissional que combina saúde, assistência e educação. Este ensaio descreve o surgimento e o desenvolvimento da prática de aconselhamento genético e apresenta alguns de seus desafios éticos.

Universum vai pluriversum : vanha kiista uudesta maailmanjärjestyksestä

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