How stem cells can support the cortex
Why is this important? The cerebral cortex is the most complex structure of our brain. And nerve cells (or neurons) which are precisely the target of most neurological and psychiatric diseases such as epilepsy, stroke, Alzheimer's disease or schizophrenia. Knowing how the machine of the cortex and how it is constructed and could be repaired is the key to the development of advanced treatment of these diseases.
Led by Pierre Vanderhaeghen, FNRS researcher at the Institute for Interdisciplinary Research in Human and Molecular Biology, Free University of Brussels, a team of European researchers has observed for the first time the internal mechanism of a cell strain that evolves neuron in the cortex. And how to inject a new brain to try to help them work better!
This discovery was made in two stages. Phase One: Nicolas Gaspard, an aspirant FNRS team discovered that embryonic stem cells (cells "multipotent" from the early embryo and can almost serve as a "universal replacement parts" in the body) can be transformed into neurons in the cortex by a spontaneous mechanism surprisingly simple and effective, summarizing much of the complex development of the cerebral cortex but in cell culture dishes, the famous petri dishes in laboratories. These neurons, although generated entirely outside the brain, without any connection with the rest of the body of the mice are fully functional and resemble in all respects with native cortical neurons. "It's a surprise to see that the cell appears to have in it all genetic resources to develop and she chooses to become a priority cell cortex, focused vision, "explains Pierre Vanderhaeghen. It undermines the view that stem cell evolves in a certain direction under the influence of the body. "
Although differentiating themselves in an environment neutral and basic food consists of basic cellular and insulin, these neurons develop a wide range of capabilities, but correspond mainly to visual and limbic regions of the brain. The limbic system consists of a set of regions (cortical and subcortical) brain involved in memory and emotions such as fear or pleasure, and affecting the endocrine and autonomic nervous system.
But the discovery does not stop there. Phase two: with the help of Dr. Afsaneh Gaillard (University of Poitiers), the researchers then transplanted these neurons into the brains of mice. Surprise: the grafted neurons and are able to connect with the host brain to form specific neural circuits of the cortex. One month after transplantation, the transplanted cells compared with the neurons of origin has found that most new neurons were connected with many parts of the brains of mice such as the striatum, thalamus and other cortical regions, thus reproducing the functional characteristics of different layers of the cortex. The researchers also found that the period of differentiation before transplantation had an influence on the brain area preferentially connected by neurons from stem cells, exactly as in the developing cortex or neurons targeting different regions are produced at times different.
Undoubtedly, this research jointly with others, who have such permits to produce neurons from skin cells of a patient opens the door to better treatments of brain diseases.