Press review
Carvalho et al in Elife - January 2020

Vangl2 acts at the interface between actin and N-cadherin to modulate mammalian neuronal outgrowth. Steve Dos-Santos Carvalho, Maite M Moreau, Yeri Esther Hien, Michael Garcia, Nathalie Aubailly, Deborah J Henderson, Vincent Studer, Nathalie Sans, Olivier Thoumine, Mireille Montcouquiol. eLife. 2020-01-07. 9.

Here, we show that an early deletion of vangl2 in neuronal progenitors of the forebrain leads to the spatially restricted deficit of only two commissural axon bundles. Mechanistically, we show that the absence of vangl2 leads to an increase in axonal outgrowth due to a reduced turnover of N-cadherin, and a better coupling between the adhesion molecule and the dynamic actin flow in the growth cone. Our results support a model in which Vangl2 acts as a regulator of membrane protein endocytosis and junctional remodeling during growth cone exploration, thereby modulating its outgrowth.

This study benefited from a close collaboration between the groups of Montcouquiol/Sans (Neurocentre Magendie), O. Thoumine (IINS), and V. Studer (IINS), funded by the Labex BRAIN (project PCP Compass).

mTORC1 and CB1 receptor signaling regulate excitatory glutamatergic inputs onto the hypothalamic paraventricular nucleus in response to energy availability

Wilfrid Mazier, Nicolas Saucisse, Vincent Simon, Astrid Cannich, Giovanni Marsicano, Federico Massa & Daniela Cota

CB1 receptors in the anterior piriform cortex control odor preference memory
Geoffrey Terral1,2, Arnau Busquets-Garcia1,2, Marjorie Varilh1,2, Svein Achicallende3,4, Astrid Cannich1,2, Luigi Bellocchio1,2, Itziar Bonilla-Del Río3,4, Federico Massa1,2, Nagore Puente3,4, Edgar Soria-Gomez1,2,3,4,5, Pedro Grandes3,4, Guillaume Ferreira2,6,* & Giovanni Marsicano1,2,*

The work of the Frick team was featured at a recent Simon's Foundation workshop exploring atypical sensory experience in autism

Collaboration Team Beyeler in Nature:
Dopamine modulates medial prefrontal cortex (mPFC) activity to mediate diverse behavioural functions. However, the precise circuit computations remain unknown. One potentially unifying model by which dopamine may underlie a diversity of functions is by modulating the signal-to-noise ratio in subpopulations of mPFC neurons. Here we demonstrate that dopamine increases the signal-to-noise ratio of responses to aversive stimuli in mPFC neurons projecting to the dorsal periaqueductal grey (dPAG). This data highlight how dopamine in the mPFC can selectively route sensory information to specific downstream circuits, representing a potential circuit mechanism for valence processing.

Interview de Nora Abrous, Directeur de recherche à l'Inserm au Neurocentre Magendie à Bordeaux. Elle est notamment spécialiste en neurobiologie du développement, mémoire et système de mémoire, vieillissement cérébral, apprentissage, vulnérabilité et addictions. Elle dirige l'équipe "Neurogenèse et physiopathologie".
Émission autour du cerveau, de la mémoire et du vieillissement sur France Bleu

Team “Neurogenesis and pathophysiology”. Neurocentre Magendie / Bordeaux Neurocampus:

The dentate gyrus (DG) of the hippocampus is one of the few mammalian brain structures where neurogenesis is maintained throughout the lifetime of individuals. Indeed the dentate granule cells (GCs), the main neuronal cell type in the DG, are generated via several distinct phases occurring during late embryogenesis, the early postnatal life, the juvenile period and throughout adulthood. Because of this continuous addition of new cells, the DG appears as a heterogeneous structure composed of different populations of granule neurons. Whether these different populations have similar or distinct structural and functional properties is still a matter of debate. Surprisingly, although most dentate GCs are generated during development, little was known about their properties compared to adult-born neurons. Nevertheless, it was generally admitted that these populations are morphologically indistinguishable once mature. However a detailed and extensive analysis of developmentally-born neurons was lacking for proper comparison.

In this study, we used in vivo electroporation to label dentate GCs generated in mouse embryos (E14.5) or in neonates (P0) and followed their morphological development up to 6 months after birth. Importantly, we highlight for the first time major morphological differences with GCs born during the juvenile period (P21) or during adulthood (P84). Importantly, we also identified different morphological parameters that can be used to predict the birthdate of granule neurons in adult brain sections. In addition, our data indicate that two other poorly studied populations of GCs in the DG, the semilunar and hilar granule cells are generated during the embryonic and the neonatal periods respectively. Thus, our findings provide new insights into the development of the different populations of granule neurons in the DG and open new questions regarding their function in the brain. Indeed, the dendritic tree determines the amount and specificity of inputs a neuron receives and is involved in sophisticated signal processing and neural computation. Consequently, mature dentate GCs born at embryonic, neonatal or adult stages might contribute differently to hippocampal function. Future analyses of the inputs and functional properties of the different populations of GCs using in vivo electroporation might help to address this controversial question.(Pictures : Thomas Kerloch, Nora Abrous, Emilie Pacary)

Dentate Granule Neurons Generated During Perinatal Life Display Distinct Morphological Features Compared With Later-Born Neurons in the Mouse Hippocampus. Thomas Kerloch, Solène Clavreul, Adeline Goron, Djoher Nora Abrous, Emilie Pacary. Cereb Cortex. 2018 Sep 12. doi: 10.1093/cercor/bhy224.

Busquets-Garcia A, Oliveira da Cruz J, Terral G, Pagano Zottola AC, Soria-Gómez E, Contini A, Martin H, Redon B, Varilh M, Ioannidou C, Drago F, Massa F, Fioramonti X, Trifilieff P, Ferreira G*, Marsicano G* (2018).Hippocampal CB1 receptors control incidental associations. Neuron

The team of Ian Wickersham at MIT developped a new generation of non toxic rabies vectors. Anna Beyeler was part of the team showing that neurons were still functioning normally up to four months after infection. In this new construct the gene coding for the polymerase necessary for transcribing viral genes was deleted. Without this gene, the virus becomes less harmful and infected cells can survive much longer.

Dix ans pour mettre au point une gélule qui peut changer la vie de beaucoup d'addicts, une vie qui peut tourner au cauchemar.
C'est un travail d'équipe au long cours qui a ses racines à Bordeaux. Au cours de ses recherches sur les effets du canabis, l'équipe du Neurocentre Magendie a découvert que sa prise entraîne la production dans le cerveau d’une molécule appelée prégnénolone. Elle a pour effet naturel de défendre l’organisme contre les effets de cette drogue. Une solution pour soigner l'addiction au cannabis. Impossible de l'utiliser en tant que telle, elle ne s'y prête pas. Les chercheurs, fédérés autour de Pier-Vincenzo Piazza, directeur de recherche Inserm, ont donc trouver la parade...