Polarisation, an indispensable step in neuron migration

Among the pathologies which affect the brain, there are the infamous Alzheimer’s and Parkinson’s diseases due to degeneration linked to the age of the organ. But disorders can also occur in the brain at the start of life, at the moment when the cerebral cortex is being formed. One class of congenital illness specific to the cerebral cortex is called lissencephaly. In fact, this term describes a set of disorders which have in common a somewhat smooth brain surface. It involves abnormalities linked to the formation of the gyri of the cerebral cortex.  “The main characteristic of these illnesses is a default of neuron migration which results in a problem of multipolar-bipolar conversion of migrating neurons”, indicates Laurent Nguyen. The researcher and his team are interested in the way in which newborn neurons find their definitive place in the cerebral cortex.  “We look at all the stages: proliferation, cell cycle exit of stem cells, the way the neurons migrate and how they settle and differentiate in the pre-existing neuronal networks of the cortex”, explains the scientist (see articles; The double life of neurotransmitters, The migration of cortical interneurons, The migration of neurons under the wing of Elongator, Towards a better understanding of Huntington’s disease). In the context of a new study recently published in Cell Reports (1), the researchers from Liege have studied the mode of migration of projection neurons when the cortex already has a certain level of thickness. “At this stage, the neurons use different modes of migration and in order to do this they have to adapt their shape”, explains Laurent Nguyen.

(1) Volvert, M.-L., Prévot, P.-P., Close, P., Laguesse,S., Pirotte, S., Hemphill, J., Rogister, F., Kruzy, N., Sacheli, R., Moonen, R., Deiters, A., Merkenschlager, M., Chariot, A., Malgrange, B., Godin, J., and Nguyen, L. : MicroRNA Targeting of CoREST Controls Polarization of Migrating Cortical Neurons, Cell Rep (2014) http://dx.doi.org/10.1016/j.celrep.2014.03.075