Neurocentre Magendie

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General informations
25/09/2019






General informations
12/09/2019
Bravo Sybille! (Planar Polarity and Plasticity Team )

Congratulations to our M2 student, Sybille Marchese (Team Montcouquiol/Sans), who has won a doctoral contract at the University of Saint Andrews in Scotland with the young team of Dr Juan Alberto Varela, winner of the prestigious ERC programme (https://risweb.st-andrews.ac.uk/portal/en/persons/juan-alberto-varela(bf1154ef-1d43-41e1-b529-7dd9660cea91).html).

Sybille will use super-resolution imaging techniques to elucidate the extracellular trafficking of protein aggregates (beta-amyloid and alpha-synuclein) in the brain and their direct role in early neurodegeneration.

Good luck Sybille!






Mireille Montcouquiol is the laureate of funding for the highly selective Fondation pour l'Audition created by Franoise Bettencourt Meyers, Jean-Pierre Meyers and the Bettencourt Schueller Foundation. Congrats !!




PhD/HDR defense
17/06/2019 13h30
Stéphanie MAURIAC from Montcouquiol-Sans's lab will give a presentation entitled ...

from Montcouquiol-Sans's lab will give a presentation entitled ...
Date de la soutenance: 17/06/2019 - 13h30
Lieu: Neurocentre Magendie Seminar room


Seminars
15/02/2019 11h30
Isabelle Brunet, Collège de France - Molecular Control of Neuro-Vascular Development

Meeting room: CGFB Seminar room

Invitant : Mireille Montcouquiol (Neurocentre Magendie, Montcouquiol-Sans's lab)

Sympathetic arterial innervation and EphrinaA4/EPHA4 Signaling: Arteries under pressure?
Abstract

Arteries receive a sympathetic innervation which is crucial to control their contraction level. Sympathetic nerves establish „“en passant““ synapses, called neurovascular junctions with arterial smooth muscle cells. Gene expres- sion comparison of non-innervated and innervated arteries revealed that the re- pulsive axon guidance molecule EphrinA4 is surprisingly expressed by arteries ar the onset of innervation (Postnatal day 2 P2). We here investigated the role of EphrinA4 signalization in the development and physiology of arterial innervation in mice. We showed that EphrinA4 is expressed by smooth muscle cells of resistance arteries and identified its receptor EphA4, expressed by sympathetic neurons. Binding and collapse experiments showed that EphrinA4 mediates the collapse of sympathetic growth cones in vitro via EphA4. EphrinA4 KO and EphA4 KO mice exhibited an increased arterial innervation at P2, consistent with a loss of repulsion. We then generated EphA4 flox-TH CRE mice who exhibited the same enhanced arterial innervation at P2 , which remained in adult mice. Increased arterial innervation in EPhA4 flox-TH CRE mice was correlated with a higher number of neurovascular junctions and a modifcation of their structure visible by eletronic microscopy. Measurement of cutaneous blood flow using laser doppler revealed an enhanced vasoconstriction in this mice. Resistivity and pulstility index of ca- rotids calculated from ultrasound views were increased, suggesting enhanced vascular resistivity. Thus EphrinA4 expressed by arterial smooth muscles cells induces collapse of sympathetic growth cones via the receptor EphA4 to refine sympathetic arterial innervation. Impairment of EphrinA4/EphA4 signaling leads to increased arterial innervation, vascular resistance and vasoconstriction. As systemic blood pressure depends on cardiac output but also vascular resistance, we are currently testing if those functional defects could lead to hypertension from sympathetic origin, or at least aggravate pre-existing hypertension.

Selected publications

– Minocha, S., Valloton, D., Brunet, I., Eichmann, A., Hornung, J.-P., Lebrand, C., (2015), NG2 glia are required for vessel network formation during embryonic development. Elife 4.

– Aspalter, I.M., Gordon, E., Dubrac, A., Ragab, A., Narloch, J., Vizán, P., Geudens, I., Collins, R.T., Franco, C.A., Abrahams, C.L., Thurston, G., Fruttiger, M., Rosewell, I., Eichmann, A., Gerhardt, H., (2015). Alk1 and Alk5 inhibition by Nrp1 controls vascular sprouting downstream of Notch. Nat Commun 6, 7264.

– Fortuna, V., Pardanaud, L., Brunet, I., Ola, R., Ristori, E., Santoro, M.M., Nicoli, S., and Eichmann, A. (2015). Vascular Mural Cells Promote Noradrenergic Differentiation of Embryonic Sympathetic Neurons. Cell Rep 11, 1786–1796.

– Rama N., Dubrac A., Mathivet T., Ní Chárthaigh R.-A., Genet G., Cristofaro B., Pibouin-Fragner L., Ma L., Eichmann A. & Chédotal A. (2015), Slit2 signaling through Robo1 and Robo2 is required for retinal neovascularization. Nat. Med. 21, 483–491.



Hottopic
28/11/2018 10h00
Mehdi BHOURI from Montcouquiol-Sans's lab will give a presentation entitled 'Role of the planar cell polarity protein Vangl2 in hippocampal circuits involved in memory.'

Hottopic
31/10/2018 10h00
Jerome EZAN from Montcouquiol-Sans's lab will give a presentation entitled 'Magendie Scientific life: why it is important to register to Hot-topics'

Hottopic
30/05/2018 10h30
Stephanie MAURIAC from Montcouquiol-Sans's lab will give a presentation entitled ' Identification of a common molecular basis leading to hearing deficit and corpus callosum agenesis in a rare disease'.

Hottopic
28/02/2018 10h00
Ana DORREGO-RIVAS from Montcouquiol-Sans's lab will give a presentation entitled "The Axonal Initial Segment (AIS): a hub for cell polarity ?"

PhD/HDR defense
04/12/2017 14h30
Benjamin Robert Benjamin Robert from the Montcouquiol-Sans' lab will defend his Ph.D. thesis entitled « Rôle de la signalisation de la polarité cellulaire planaire dans les processus mnésiques »

Benjamin Robert from the Montcouquiol-Sans' lab will defend his Ph.D. thesis entitled « Rôle de la signalisation de la polarité cellulaire planaire dans les processus mnésiques »
Date de la soutenance: 04/12/2017 - 14h30
Lieu: Neurocentre Magendie Seminar room

Pour plus de détails: http://www.bordeaux-neurocampus.fr/fr/formation-doctorale/these-2017/benjamin-robert.html