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For the first time ever, researchers have
shown how a neuronal precursor progressively acquires functional characteristics
to become a true neuron. This research, led by the team of Pierre-Marie
Lledo, research director at the CNRS and head of the "Olfactory Memory
and Perception" Unit of the Institut Pasteur (affiliated with the
CNRS), in partnership with the research team led by Arturo Alvarez-Buylla
of the University of California in San Francisco, was initially published
on the Nature Neuroscience WEB site on April 21, 2003. This research should
contribute to the development of new treatment strategies.
We have very recently learned that stem
cells are capable of producing new neurons in adults. A cell proliferation
zone located at the very center of the brain continually generates immature
neurons. These young cells migrate over long distances (several centimeters
in humans), at very high speed (100 µm/hour), thanks to a "chain"
cell migration process, before reaching their target tissues.
Even if considerable progress has been made on
the procedures for producing immature neurons, research has yet to be
done on the maturation stages, functional consequences and means of integration
of the arrival of newborn neurons. Researchers at the CNRS/Institut Pasteur
and the University of California followed the evolution in mice of neurons
born in the subventricular zone bordering on the cerebral ventricles and
migrating toward the olfactory bulb, the first brain relay of the olfactory
signal, where young cells progressively differentiate into neurons. Approximately
two weeks are required for a new cell to reach the olfactory bulb and
to integrate itself into the existing network. Researchers have shown
that the brain's ability to produce new neurons is related to unique mechanisms
adapted to the adult brain, very different from embryonic processes. Moreover,
they have demonstrated that newly produced neurons are not only capable
of integrating themselves into a pre-existing network but also and above
all, that they confer new properties on this same neuron network.
"This research has increased our knowledge
of the regenerative functions and mechanisms of the central nervous system.
At the therapeutic level, this research offers new possibilities aimed
at transplanting or rerouting newly formed neurons in the brain from the
areas in which they originate. Many questions obviously need to be answered.
How does a newborn neuron cell migrate and find its target? How does it
choose its future cellular role", says Pierre-Marie Lledo. These
are just some of the questions that researchers are trying to answer at
this time.
For more information: http://www.nature.com/neuro/
"Becoming a new neuron in the
adult olfactory bulb". Nature Neuroscience. May 2003.
Researcher
contact:
Pierre-Marie Lledo
Tel: +33 1 45 68 88 03
E-mail: pmlledo@pasteur.fr
Press Contacts:
CNRS:
Martine Hasler
Tel: +33 1 44 96 46 35
E-mail: martine.hasler@cnrs-dir.fr
Institut Pasteur: Press Office
Tel: +33 1 45 68 81 46
E-mail: presse@pasteur.fr
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