Brain development, repair and ageing

BDRA studies mechanisms underlying the development, repair and ageing of the brain, using cerebellar and hippocampal models in vivo and in vitro, to address fundamental biological bases of these phenomena and to explore clinical applications.

We are studying genes and signaling pathways that allow selective synapse stabilization during olivocerebellar development and promote appropriate post-lesion repair. We also examine the formation, maintenance and disruption of homeostatic synaptic plasticity, which is necessary to maintain functional stability in neural circuits while allowing their flexibility. Finally, we investigate the roles of different proteins associated with Alzheimer’s disease to understand early hippocampal synaptic dysfunction during this age-related pathology.

In addition we are applying our understanding of neural circuit function, stability and repair to develop translational approachs. First we are building on our expertise in non-invasive psychomotor and rTMS brain stimulation to optimize maintenance, protection and repair of synaptic circuits in the damaged or ageing brain. Second, we are applying a new complete test of cognitive function, in particular episodic memory, to ageing patients in order to provide earlier diagnosis of cognitive dysfunction, thus allowing early therapeutic intervention.

The team’s multidisciplinary approach, from molecules to behavior and bench to the clinic, expands the Unit’s research fields into the evolution of accumulating synaptic dysfunction with time and the potential for its repair.

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BDRA studies mechanisms underlying the development, repair and ageing of the brain, using cerebellar and hippocampal models to address the biological bases of these phenomena and to explore clinical applications.

Our interest in synaptic maturation and function includes the genes and signalling paths permitting selective synapse stabilisation during olivocerebellar development and repair, mechanisms underlying the establishment and loss of homeostatic plasticity as well as causes of early hippocampal synaptic dysfunction in Alzheimer’s disease.

We are applying knowledge gained from these fundamental studies to develop translational approaches. First, we examine the potential for non-invasive psychomotor and magnetic brain stimulation to optimize maintenance, protection and repair of synaptic circuits in the damaged or ageing brain. Second, we are evaluating a new complete test of cognitive function for aged patients in order to provide earlier diagnosis of minimal cognitive decline and thus early therapeutic intervention.

The team’s multidisciplinary approach, from molecules to behaviour and bench to the clinic, expands the Unit’s research fields into the evolution of accumulating synaptic dysfunction with time and the potential for its repair.

Highlights

Key results within our domain of neuronal and synaptic function throughout life, include:

  • 1) Within the olivocerebellar projection, developmental synaptogenesis and selective stabilization permanently alters each synaptic partner to block their capacity to recapitulate development.
  • 2) BDNF-induced olivocerebellar repair in the maturing animal confers recovery of motor and navigation tasks; this repair is increased by psychomotor activity.
  • 3) Accumulating cognitive dysfunction with age, in the form of spatial learning deficit, directly correlates with deficits in maintaining hippocampal LTP.
  • 4) Over-expression or mutation of presenilin-1 (PS1) perturbs the establishment and maintenance of LTP in young adult mice; this impairment increases during aging, in association with dendritic spine abnormalities and learning impairment.
  • 5) ROR is a key transcription factor in the process of neuroageing. Haploinsufficiency of ROR is associated with premature PC death in the cerebellum due to early reduction of circulating sex steroids.
  • 6) In addition to neurons, ROR is expressed in astrocytes, through which it finely controls cytokine interleukin-6 expression and promotes neuronal survival following hypoxia.

Future directions

  • 1)The team will build on its achievements in the field of neural circuit repair to further characterise important mechanisms.In addition to evaluating the role of several candidate genes in this process, we will undertake transcriptome analysis of reinnervating and target tissue to find novel molecules and make in silico searches to identify new targets regulated by these candidate genes.
  • 2)We will also examine the impact of non-invasive brain stimulation paradigms on synaptic homeostasis and dendritic integration of afferent data in order to understand effects on whole network function.
  • 3)To deepen the links between fundamental biology and clinical age-related neurological problems, we add to our mouse studies on synaptic dysfunction in Alzheimer’s disease the roles of 2 potentially treatable components: (a) the roles of different glia in neuroinflammation underlying Alzheimer’s pathology; and (b) the role of sleep dysfunction especially SOAS (Sleep Obstructive Apneas Syndrome) in disease progression in mice and in Human through the patients cohorts of DHU FAST.

Collaborations

  • Borsello, Tiziana, International, Institute M. Negri, Milano, Italy
  • Harvey, Alan, International; School of anatomy and Human Biology, University of Western Australia
  • Mattick, John S, International, University of Queensland, Australia
  • Mattson, Mark P, International, National Institute on Aging, Baltimore MD, USA
  • Rodger, Jenny, International, Experimental and Regenerative Neurosciences, Uni Western Australia.
  • Sugihara, Izumi, International, University of Tokyo, Japan
  • Vogel, Michael,International, University of Maryland, Baltimore, USA.
  • Bailly, Yannick, National ; CNRS & Université de Strasbourg
  • Gressens, Pierre, Local, Inserm Hopital R. Debré Paris
  • Tedgui, Alain, Local, INSERM & HEGP hospital Paris
  • Dusart, Isabelle, Local, UMR8246
  • Di Gregorio, David, Local, Institut Pasteur, Paris