Comprehensive Pan-Genomic Characterization of Adrenocortical Carcinoma

SummaryWe describe a comprehensive genomic characterization of adrenocortical carcinoma (ACC). Using this dataset, we expand the catalogue of known ACC driver genes to include PRKAR1A, RPL22, TERF2, CCNE1, and NF1. Genome wide DNA copy-number analysis revealed frequent occurrence of massive DNA loss followed by whole-genome doubling (WGD), which was associated with aggressive clinical course, suggesting WGD is a hallmark of disease progression. Corroborating this hypothesis were increased TERT expression, decreased telomere length, and activation of cell-cycle programs. Integrated subtype analysis identified three ACC subtypes with distinct clinical outcome and molecular alterations which could be captured by a 68-CpG probe DNA-methylation signature, proposing a strategy for clinical stratification of patients based on molecular markers

Etude en microscopie de fluorescence à deux photons in vivo de l'intégration multi vibrissale chez le rat

Rats possess an array of long whiskers, they can actively move and which enable them to explore space, localize objects and discriminate textures. Sensory information coming from follicles' mecano receptors where whiskers are inserted goes through mesencephalic and thalamic relays and reaches discrete units, called "barrels", in layer IV of the primary somato-sensory cortex. Then, sensory information spreads to layer II/III of the primary somato-sensory cortex where horizontal connections enable integration of information coming from several whiskers. My work tackles the question of multi whisker integration in the somato-sensory cortex using in vivo two photon microscopy and covers mainly two chapters. I first deal with all the optical developments in two photon microscopy that were realized in order to optimize in vivo recordings of the neuronal activity. Then, I consider the question of multi whisker integration using this technique. I developed an original two photon microscopy set-up which is able to record neuronal activity in layer II/III of the cortex while giving access to the recorded neuronal network architecture. That microscope allows high speed detection of single calcium transiants while requiring low power from the excitation laser. Thus, both photo bleaching and photo toxicity are limited. Furthermore, I identified noise sources during in vivo recordings and implemented appropriate solutions (holding system, image movement correction algorithm...) to reduce or correct these noises in order to be limited only by shot noise. Finally, I evaluated individual cells recordings quality excluding all risk of important contamination by neuropil signal. Using that two photon microscope, I have studied the neuronal responses in layer II/III to different stimulations. First, applying multi-whisker stimulations showing either no or full correlations between the whiskers, I have shown that neurons are spatially segregated depending on their response to these multi-whisker stimuli, this segregation being related to the below barrel organization in layer IV. Then, I have looked at neuronal responses induced by single whisker deflections as a function of two parameters: the stimulus "phase" in the 2D space of preferred stimuli and the stimulus direction in the 2D physical space. I have shown the absence of strong correlation between "phase" and direction tunings.Le rat possède un ensemble de longues vibrisses qu'il peut bouger activement, ce qui lui permet d'explorer l'espace, de localiser les objets et de discriminer des textures. L'information sensorielle provenant des récepteurs périphériques des follicules où s'insèrent les vibrisses atteint, via des relais mésencéphaliques et thalamiques, des modules discrets, appelés " tonneaux ", de la couche IV du cortex somato-sensoriel primaire, puis se propage entre autre à la couche II/III du cortex somato-sensoriel primaire. Dans cette couche, des connexions horizontales permettent l'intégration d'informations provenant de plusieurs vibrisses différentes. Mon travail de thèse s'articule autour de la question de l'intégration multi-vibrissale dans le cortex somato-sensoriel chez le rat et est abordé grâce à la microscopie à deux photons in vivo. Il est partagé principalement en deux chapitres, le premier traitant de l'ensemble des développements optiques en microscopie à deux photons réalisés pour optimiser des enregistrements in vivo de l'activité neuronale, l'autre abordant la question de l'intégration multi-vibrissale au moyen de cette technique. J'ai donc développé un montage de microscopie à deux photons original capable d'enregistrer l'activité neuronale en couche II/III du cortex tout en donnant accès à l'architecture des réseaux enregistrés. Ce microscope permet de détecter à haute cadence des signaux calciques individuels tout en nécessitant une puissance modérée du laser d'excitation, ce qui limite la photo toxicité et le photo blanchiment. J'ai par ailleurs identifié quantitativement les différentes sources de bruits lors des enregistrements in vivo et mis en œuvre des solutions ad hoc (système de contention, algorithme de recalage des images...) pour réduire ou corriger ces bruits afin de n'être plus limité que par le bruit de photon. Enfin, j'ai estimé la qualité des enregistrements des cellules individuelles en excluant tout risque de contamination violente par des signaux collectifs tels que ceux provenant du neuropil. A l'aide de ce microscope, j'ai montré qu'il existe en couches II/III une ségrégation cellulaire selon un comportement globale ou local et que cette ségrégation s'articule au-dessus de l'organisation des tonneaux en couche IV, les cellules globales présentant une densité plus forte au-dessus des septa tandis que les cellules locales sont plus représentées au-dessus des tonneaux. Par ailleurs, au sein de la couche II/III du cortex j'ai mis en évidence l'absence de corrélation forte entre les sélectivités à la phase (dans l'espace 2D des stimuli optimaux mono-vibrisses) et à la direction (dans l'espace 2D physique) et posé les bases d'une étude de l'organisation spatiale de ces différentes sélectivités avec l'ébauche d'une cartographie fonctionnelle

A radial map of multi-whisker correlation selectivity in the rat barrel cortex

International audienceIn the barrel cortex, several features of single-whisker stimuli are organized in functionalmaps. The barrel cortex also encodes spatio-temporal correlation patterns of multi-whiskerinputs, but so far the cortical mapping of neurons tuned to such input statistics is unknown.Here we report that layer 2/3 of the rat barrel cortex contains an additional functional mapbased on neuronal tuning to correlated versus uncorrelated multi-whisker stimuli: neuronresponses to uncorrelated multi-whisker stimulation are strongest above barrel centres,whereas neuron responses to correlated and anti-correlated multi-whisker stimulation peakabove the barrel–septal borders, forming rings of multi-whisker synchrony-preferring cells

An interdisciplinary learning experience in neuro-optics.

International audienceHow can a Ph.D. student initially trained as a biologist take part in the development of a multineuronal recording method that requires cross interaction between physics, neurobiology and mathematics? Beyond student training in the laboratory, interdisciplinary research calls for a new style of academic training of young researchers. Here we present an innovative approach to graduate student academic training that fills the need for multidisciplinary knowledge and provides students, in addition, with a deeper understanding of the interdisciplinary approach to scientific research

COPI coat assembly occurs on liquid-disordered domains and the associated membrane deformations are limited by membrane tension.

International audienceCytoplasmic coat proteins are required for cargo selection and budding of tubulovesicular transport intermediates that shuttle between intracellular compartments. To better understand the physical parameters governing coat assembly and coat-induced membrane deformation, we have reconstituted the Arf1-dependent assembly of the COPI coat on giant unilamellar vesicles by using fluorescently labeled Arf1 and coatomer. Membrane recruitment of Arf1-GTP occurs exclusively on disordered lipid domains and does not induce optically visible membrane deformation. In the presence of Arf1-GTP, coatomer self-assembles into weakly curved coats on membranes under high tension, while it induces extensive membrane deformation at low membrane tension. These deformations appear to have a composition different from the parental membrane because they are protected from phase transition. These findings suggest that the COPI coat is adapted to liquid disordered membrane domains where it could promote lipid sorting and that its mechanical effects can be tuned by membrane tension

PKA regulatory subunit 1A inactivating mutation induces serotonin signaling in primary pigmented nodular adrenal disease

International audiencePrimary pigmented nodular adrenocortical disease (PPNAD) is a rare cause of ACTH-independent hypercortisolism. The disease is primarily caused by germline mutations of the protein kinase A (PKA) regulatory subunit 1A (PRKAR1A) gene, which induces constitutive activation of PKA in adrenocortical cells. Hypercortisolism is thought to result from PKA hyperactivity, but PPNAD tissues exhibit features of neuroendocrine differentiation, which may lead to stimulation of steroidogenesis by abnormally expressed neurotransmitters. We hypothesized that serotonin (5-HT) may participate in the pathophysiology of PPNAD-associated hypercortisolism. We show that PPNAD tissues overexpress the 5-HT synthesizing enzyme tryptophan hydroxylase type 2 (Tph2) and the serotonin receptors types 4, 6, and 7, leading to formation of an illicit stimulatory serotonergic loop whose pharmacological inhibition in vitro decreases cortisol production. In the human PPNAD cell line CAR47, the PKA inhibitor H-89 decreases 5-HT4 and 5-HT7 receptor expression. Moreover, in the human adrenocortical cell line H295R, inhibition of PRKAR1A expression increases the expression of Tph2 and 5-HT4/6/7 receptors, an effect that is blocked by H-89. These findings show that the serotonergic process observed in PPNAD tissues results from PKA activation by PRKAR1A mutations. They also suggest that Tph inhibitors may represent efficient treatments of hypercortisolism in patients with PPNAD

La Restauration revisitée - Les formes de la protestation - Une histoire de l'Etat

La présente livraison reflète la vitalité actuelle de l’histoire politique du xixe siècle. Sans viser la cohérence propre à un numéro thématique ni un improbable état des lieux, elle traduit néanmoins quelques lignes de force très contemporaines : le rejet d’une clôture sur la seule « vie politique », l’approche au « ras du sol » des processus de politisation, attentive à la parole des acteurs, le décloisonnement des spécialités par l’approche culturelle du politique, l’émergence du secret comme objet majeur d’enquête historique (des sociétés secrètes à l’« État secret »), et la relecture à nouveaux frais de champs aussi classiques que l’histoire parlementaire

Un siècle de sites funéraires de la Grande Guerre

Les pertes inouïes de la Grande Guerre ont entraîné la généralisation de pratiques embryonnaires auparavant : individualisation des sépultures, construction de monuments commémoratifs, multiplication des rites. Des chercheurs de nombreux pays étudient les traces de cette rupture majeure, encore largement visible dans les paysages. Tombes, cénotaphes, nécropoles, monuments et mémoriaux en représentent le témoignage matériel et culturel. Anthropologues, historiens, archéologues, spécialistes du tourisme de mémoire, retracent comment a été remémorée ce que l’on croyait être la vision du monde des disparus, du sacrifice au pacifisme. La comparaison internationale et diachronique, de la Seconde Guerre mondiale au génocide du Rwanda, donne toute leur importance à ces sites, au moment où ceux du front occidental belge et français sont candidats à entrer au patrimoine mondial de l’UNESCO. Ces témoins des consciences traversées par le malheur des guerres sont l’espoir de la réconciliation humaniste

Positive impact of genetic test on the management and outcome of patients with paraganglioma and/or pheochromocytoma

International audienceOC5.1Positive impact of genetic test on the management and outcome of patients with paraganglioma and/or pheochromocytomaContextParagangliomas and pheochromocytomas (PPGL) are rare neuroendocrine tumors, characterized by a strong genetic component. Indeed, up to 40% of patients carry a germline mutation in a PPGL susceptibility gene. In accordance with the international recommendations, genotyping of PPGL susceptibility genes is therefore proposed to all patients with PPGL, but it has actually never beenshown whether the identification of a germline mutation in one PPGL susceptibility gene changes the outcome of mutation-carriers.ObjectiveOur objective was to evaluate how a positive genetic test impacts the management and outcome of propositus patients with PPGL carrying a germline mutation in one of the four major PPGL susceptibility genes (SDHB, SDHD, SDHC and VHL).DesignWe performed a multicentric retrospective study on 221 propositus carrying a SDHB, SDHD, SDHC or VHL germline mutation and followed in 24 French clinical centers of the Group of Endocrine Tumors and/or the COMETE network. Patients were divided into two groups: Genetic patients, who were informed of their genetic status within the year following the first PPGL diagnosis, and Historic patients who only benefited from the genetic test several years after initial PPGL diagnosis.ResultsCompared to Historic patients, Genetic patients had a better follow-up, with a higher number of examinations and a reduced number of patients lost to follow-up (9.6% versus 72%). During follow-up, smaller (18.7 mm versus 27.6, PZ0.0128) new PPGL and metastases as well as lower metastatic spread were observed in Genetic patients. Importantly, these differences were reversed in the Historic cohort after genetic testing. Genetic patients who developed metachronous metastases had a better 5-year survival than Historic ones (PZ0.0127).ConclusionAltogether our study clearly shows the positive impact of the identification of an SDHx or VHL mutation in the management, clinical outcome and survival of patients with PPGL. It reveals, for the first time, the clinical benefits of the practice of oncogenetics for patients with a rare cancer and strongly strengthens the recommendations of the Endocrine Society to consider PPGL genetic testingin all patients affected by PPGL.DOI: 10.1530/endoabs.63.OC5.