The Photoreceptor Cell-Specific Nuclear Receptor Gene (PNR ) Accounts for Retinitis Pigmentosa in the Crypto-Jews from Portugal (Marranos), Survivors from the Spanish Inquisition

The last Crypto-Jews (Marranos) are the survivors of Spanish Jews who were persecuted in the late fifteenth century, escaped to Portugal and were forced to convert to save their lives. Isolated groups still exist in mountainous areas such as Belmonte in the Beira-Baixa province of Portugal. We report here the genetic study of a highly consanguineous endogamic population of Crypto-Jews of Belmonte affected with autosomal recessive retinitis pigmentosa (RP). A genome-wide search for homozygosity allowed us to localize the disease gene to chromosome 15q22-q24 (Zmax=2.95 at θ=0 at the D15S131 locus). Interestingly, the photoreceptor cell-specific nuclear receptor (PNR) gene, the expression of which is restricted to the outer nuclear layer of retinal photoreceptor cells, was found to map to the YAC contig encompassing the disease locus. A search for mutations allowed us to ascribe the RP of Crypto-Jews of Belmonte to a homozygous missense mutation in the PNR gene. Preliminary haplotype studies support the view that this mutation is relatively ancient but probably occurred after the population settled in Belmonte

Cone rod dystrophies

Cone rod dystrophies (CRDs) (prevalence 1/40,000) are inherited retinal dystrophies that belong to the group of pigmentary retinopathies. CRDs are characterized by retinal pigment deposits visible on fundus examination, predominantly localized to the macular region. In contrast to typical retinitis pigmentosa (RP), also called the rod cone dystrophies (RCDs) resulting from the primary loss in rod photoreceptors and later followed by the secondary loss in cone photoreceptors, CRDs reflect the opposite sequence of events. CRD is characterized by primary cone involvement, or, sometimes, by concomitant loss of both cones and rods that explains the predominant symptoms of CRDs: decreased visual acuity, color vision defects, photoaversion and decreased sensitivity in the central visual field, later followed by progressive loss in peripheral vision and night blindness. The clinical course of CRDs is generally more severe and rapid than that of RCDs, leading to earlier legal blindness and disability. At end stage, however, CRDs do not differ from RCDs. CRDs are most frequently non syndromic, but they may also be part of several syndromes, such as Bardet Biedl syndrome and Spinocerebellar Ataxia Type 7 (SCA7). Non syndromic CRDs are genetically heterogeneous (ten cloned genes and three loci have been identified so far). The four major causative genes involved in the pathogenesis of CRDs are ABCA4 (which causes Stargardt disease and also 30 to 60% of autosomal recessive CRDs), CRX and GUCY2D (which are responsible for many reported cases of autosomal dominant CRDs), and RPGR (which causes about 2/3 of X-linked RP and also an undetermined percentage of X-linked CRDs). It is likely that highly deleterious mutations in genes that otherwise cause RP or macular dystrophy may also lead to CRDs. The diagnosis of CRDs is based on clinical history, fundus examination and electroretinogram. Molecular diagnosis can be made for some genes, genetic counseling is always advised. Currently, there is no therapy that stops the evolution of the disease or restores the vision, and the visual prognosis is poor. Management aims at slowing down the degenerative process, treating the complications and helping patients to cope with the social and psychological impact of blindness

A novel locus (CORD12) for autosomal dominant cone-rod dystrophy on chromosome 2q24.2-2q33.1

<p>Abstract</p> <p>Background</p> <p>Rod-cone dystrophy, also known as retinitis pigmentosa (RP), and cone-rod dystrophy (CRD) are degenerative retinal dystrophies leading to blindness. To identify new genes responsible for these diseases, we have studied one large non consanguineous French family with autosomal dominant (ad) CRD.</p> <p>Methods</p> <p>Family members underwent detailed ophthalmological examination. Linkage analysis using microsatellite markers and a whole-genome SNP analysis with the use of Affymetrix 250 K SNP chips were performed. Five candidate genes within the candidate region were screened for mutations by direct sequencing.</p> <p>Results</p> <p>We first excluded the involvement of known adRP and adCRD genes in the family by genotyping and linkage analysis. Then, we undertook a whole-genome scan on 22 individuals in the family. The analysis revealed a 41.3-Mb locus on position 2q24.2-2q33.1. This locus was confirmed by linkage analysis with specific markers of this region. The maximum LOD score was 2.86 at θ = 0 for this locus. Five candidate genes, <it>CERKL</it>, <it>BBS5, KLHL23, NEUROD1</it>, and <it>SF3B1 </it>within this locus, were not mutated.</p> <p>Conclusion</p> <p>A novel locus for adCRD, named <it>CORD12</it>, has been mapped to chromosome 2q24.2-2q33.1 in a non consanguineous French family.</p

Leber Congenital Amaurosis: Comprehensive Survey of the Genetic Heterogeneity, Refinement of the Clinical Definition, and Genotype-Phenotype Correlations as a Strategy for Molecular Diagnosis

Communicated by Jean-Claude Kaplan Leber congenital amaurosis (LCA) is the earliest and most severe form of all inherited retinal dystrophies, responsible for congenital blindness. Disease-associated mutations have been hitherto reported in seven genes. These genes are all expressed preferentially in the photoreceptor cells or the retinal pigment epithelium but they are involved in strikingly different physiologic pathways resulting in an unforeseeable physiopathologic variety. This wide genetic and physiologic heterogeneity that could largely increase in the coming years, hinders the molecular diagnosis in LCA patients. The genotyping is, however, required to establish genetically defined subgroups of patients ready for therapy. Here, we report a comprehensive mutational analysis of the all known genes in 179 unrelated LCA patients, including 52 familial and 127 sporadic (27/127 consanguineous) cases. Mutations were identified in 47.5% patients. GUCY2D appeared to account for most LCA cases of our series (21.2%), followed by CRB1 (10%), RPE65 (6.1%), RPGRIP1 (4.5%), AIPL1 (3.4%), TULP1 (1.7%), and CRX (0.6%). The clinical history of all patients with mutations was carefully revisited to search for phenotype variations. Sound genotype-phenotype correlations were found that allowed us to divide patients into two main groups. The first one includes patients whose symptoms fit the traditional definition of LCA, i.e., congenital or very early cone-rod dystrophy, while the second group gathers patients affected with severe yet progressive rodcone dystrophy. Besides, objective ophthalmologic data allowed us to subdivide each group into two subtypes. Based on these findings, we have drawn decisional flowcharts directing the molecular analysis of LCA genes in a given case. These flowcharts will hopefully lighten the heavy task of genotyping new patients but only if one has access to the most precise clinical history since birth

Loss of the Metalloprotease ADAM9 Leads to Cone-Rod Dystrophy in Humans and Retinal Degeneration in Mice

Cone-rod dystrophy (CRD) is an inherited progressive retinal dystrophy affecting the function of cone and rod photoreceptors. By autozygosity mapping, we identified null mutations in the ADAM metallopeptidase domain 9 (ADAM9) gene in four consanguineous families with recessively inherited early-onset CRD. We also found reduced photoreceptor responses in Adam9 knockout mice, previously reported to be asymptomatic. In 12-month-old knockout mice, photoreceptors appear normal, but the apical processes of the retinal pigment epithelium (RPE) cells are disorganized and contact between photoreceptor outer segments (POSs) and the RPE apical surface is compromised. In 20-month-old mice, there is clear evidence of progressive retinal degeneration with disorganized POS and thinning of the outer nuclear layer (ONL) in addition to the anomaly at the POS-RPE junction. RPE basal deposits and macrophages were also apparent in older mice. These findings therefore not only identify ADAM9 as a CRD gene but also identify a form of pathology wherein retinal disease first manifests at the POS-RPE junction

A Human TREK-1/HEK Cell Line: A Highly Efficient Screening Tool for Drug Development in Neurological Diseases

TREK-1 potassium channels are involved in a number of physiopathological processes such as neuroprotection, pain and depression. Molecules able to open or to block these channels can be clinically important. Having a cell model for screening such molecules is of particular interest. Here, we describe the development of the first available cell line that constituvely expresses the TREK-1 channel. The TREK-1 channel expressed by the h-TREK-1/HEK cell line has conserved all its modulation properties. It is opened by stretch, pH, polyunsaturated fatty acids and by the neuroprotective molecule, riluzole and it is blocked by spadin or fluoxetine. We also demonstrate that the h-TREK-1/HEK cell line is protected against ischemia by using the oxygen-glucose deprivation model

Effects of chronic phthalate exposure on sexual and cognitive behaviors in adult male mice

Les phtalates sont des perturbateurs endocriniens fréquemment détectés dans l’environnement en raison de leur utilisation intensive dans la fabrication et le traitement de nombreux produits, ce qui provoque une large contamination environnementale et humaine. L’exposition chronique à l’âge adulte au DEHP seul à des faibles doses comprises dans la fenêtre d’exposition environnementale induit des altérations du comportement sexuel. Cette vulnérabilité est associée à une sous-expression du récepteur des androgènes (AR) dans le circuit neural impliqué dans la régulation du comportement sexuel, mais aussi dans l’hippocampe. L’hippocampe est une structure sensible aux androgènes avec une modulation par de la testostérone via l’AR de comportements cognitifs. Ce projet de thèse s’est donc intéressé aux effets et mécanismes de l’exposition chronique de souris mâles adultes au DEHP seul ou en mélange de phtalates sur le comportement sexuel et l’apprentissage et mémoire. L’exposition au DEHP seul ou en mélange de phtalates altère le comportement sexuel avec une diminution de l’émission des vocalisations ultrasonores, de l’attractivité des mâles ou de leur urine et du comportement copulatoire. Des perturbations de comportements hippocampe-dépendants comme la mémoire spatiale et temporelle ont été également observées. De manière intéressante, ces altérations comportementales ont été associées à des modifications de la plasticité synaptique structurale et fonctionnelle avec une diminution de la densité des épines dendritiques et des niveaux protéiques de marqueurs pré- et postsynaptiques dans l’aire préoptique, région clé du comportement sexuel, et dans les régions CA1 et CA2/3 de l’hippocampe impliquées dans les processus d’apprentissage et de mémoire. L’ensemble des résultats obtenus associés à des analyses métabolomiques réalisées par nos collaborateurs ont permis de proposer un « Adverse Outcome Pathway » pour les effets de l’exposition adulte aux phtalates sur le système nerveux central mâle.Phthalates are endocrine disruptors frequently detected in the environment due to their extensive use in the manufacture and processing of many products, resulting in widespread environmental and human contamination. Chronic adult exposure to DEHP alone at low doses within the environmental exposure window induces alterations in sexual behavior. This vulnerability is associated with under-expression of the androgen receptor (AR) in the neural circuitry involved in the regulation of sexual behavior, but also in the hippocampus. The hippocampus is an androgen-sensitive structure with modulation by testosterone via the AR of cognitive behaviors. This thesis project therefore investigated the effects and mechanisms of chronic exposure of adult male mice to DEHP alone or in a mixture of phthalates on sexual behavior and learning and memory. Exposure to DEHP alone or in a mixture of phthalates alters sexual behavior with a decrease in the emission of ultrasonic vocalizations, the attractiveness of males or their urine and copulatory behavior. Disruptions in hippocampal-dependent behaviors such as spatial and temporal memory were also observed. Interestingly, these behavioral alterations were associated with changes in structural and functional synaptic plasticity with a decrease in the density of dendritic spines and protein levels of pre- and postsynaptic markers in the preoptic area, a key region for sexual behavior, and in the CA1 and CA2/3 regions of the hippocampus involved in learning and memory processes. All the results obtained associated with metabolomic analyses carried out by our collaborators allowed us to propose an "Adverse Outcome Pathway" for the effects of adult exposure to phthalates on the male central nervous system

Etude inter-tissu et inter-espèce des mécanismes d'action cellulaires et membranaires cardiaques de substances antiarythmiques K+- bloquantes sur tissu sain et en conditions d'ischémie-reperfusion

Le mode d'action des médicaments antiarythmiques de classe III consiste en un blocage des canaux potassiques responsables de la repolarisation du potentiel d'action dans les cellules myocardiques. Ces médicaments se sont révélés efficaces dans le traitement des fibrillations auriculaires. Cependant, leur utilisation est retreinte du fait de leurs propriétés proarythmiques. En effet, ces substances peuvent être à l'origine d'arythmies létales : les torsade-de-pointes dont le mécanisme initiateur correspond, au moins en partie, en l'apparition de postdépolarisations précoces. Le but du travail ici présenté, a été de caractériser cinq médicaments antiarythmiques de classe III capables de bloquer les courants Ikr et/ou Iks en terme de potentialité.1) proarythmique sur un modèle d'induction de postdépolarisations précoces dans les fibres de Purkinje cardiaques isolées de lapin.2) antiarythmique sur un modèle in vitro de myocarde ventriculaire de cobaye soumis à un phénomène d'ischémie-reperfusion.Nous avons ainsi montré que des bloqueurs spécifiques du courant Ikr le dofetilide et le d-sotalol induisent une prolongation importante de la durée du potentiel d'action des fibres de Purkinje de lapin et de l'endocarde ventriculaire de cobaye. Cet effet confère à ce type de substance un risque élevé d'induction de postdépolarisations précoces mais également une efficacité notable dans le traitement des arythmies ventriculaires induites par l'ischémie et la reperfusion. Les bloqueurs spécifiques du courant Iks, le chromanol 293B et le HMR 1556, sont dépourvus d'effets sur le potentiel d'action des fibres de Purkinje de lapin tandis qu'ils allongent modérément la repolarisation des cellules endocardiques de cobaye. Il en résulte un risque proarythmique nul mais également une absence d'effet cardioprotecteur au cours de l'ischémie-reperfusion dans le modèle utilisé. Enfin, l'azimilide, dont la particularité est de bloquer à la fois les courants Ikr et Iks, allonge de façon importante la durée du potentiel d'action dans les deux préparations cellulaires étudiées, du fait de son aptitude à réduire l'amplitude d'Ikr. Ce médicament s'est révélé associé, au cours de notre étude, à un risque proarythmique non négligeable. L'azimilide a également présenté des effets variables au cours de l'ischémie-reperfusion : il prévient l'apparition des arythmies ventriculaires liées à la reperfusion myocardique mais reste sans effet au cours de l'ischémie.CAEN-BU Médecine pharmacie (141182102) / SudocSudocFranceF

Les pieux maritimes du pont Vasco da Gama

Les pieux maritimes du pont Vasco da Gama constituaient un de ses enjeux techniques principaux pour le groupement d’entreprises NOVAPONTE (piloté par Campenon Bernard SGE), qui avait pris à son compte les aléas de fondations. Quelques chiffres en témoignent :– 8 km d’estuaire à franchir, soumis à l’action de la marée ;– 860 pieux de 1,70 à 2,20 m de diamètre pour des capacités portantes supérieures à 3 000 t sous séisme, fondés jusqu’à – 85 m sous le niveau moyen du fleuve ;– des cadences de production moyennes de deux pieux battus et un pieu foré par jour