Nerve cells from fibroblasts "three in one"
Skin cells turned into brain cells in one step
At the same time, the researchers managed to bypass the intermediate stage of stem cells.
According to the head of the work, Marius Wernig, "the results obtained and their therapeutic potential brought him and his colleagues into awe."
"We have shown that nerve cells grown from skin cells (fibroblasts) in the mouse brain integrate and produce a protein necessary for the transmission of an electrical signal between neurons. This is important because we use mice as models to study human brain diseases," explains Wernig.
In their experiments, Stanford scientists introduced a virus with three transcription factors (Brn2, Sox2 and FoxG1) into laboratory germ cell lines of mice, the level of which in the precursor cells of nerve cells is quite high. Three weeks later, every tenth skin cell acquired the external and functional signs of a nerve precursor cell.
The researchers confirmed the presence of nerve cell progenitor cells both in vitro ("in vitro") and in vivo (in animals).
In vitro, it has been shown that the same genes are active in transformed cells as in ordinary nerve progenitor cells, and they themselves have the same shape as the progenitor cells. The progenitor cells transformed from skin cells gave rise to different types of nerve cells, in particular, astrocytes and oligodendrocytes.
In experiments with animals, scientists introduced transformed cells into the brains of newborn mice of a special line. These were rodents that could not produce a myelin layer protecting nerve fibers. Ten weeks after the transplant, the new cells differentiated into oligodendrocytes, thanks to which the myelin sheath of nerve fibers necessary for the normal function of the nervous system is formed.
(The figure shows oligodendrocytes in the corpus callosum of the mouse brain. Confocal microscopy with immunofluorescence. Image from the website mdc-berlin.de .)
Neuron progenitor cells, according to experts, can be widely used in biomedical research, since they can be cultured in large quantities for both transplantation and drug screening.
In previous similar experiments, the formation of nervous system cells from skin cells was preceded by the stage of stem cells, or rather, pluripotent cells, which can transform into all types of cells of the body. Nerve cells were obtained by reprogramming skin cells using several transcription factors, among which were those that activate oncogenes.
In order to demonstrate not only the possibility and effectiveness, but also the safety of such a conversion of human skin cells, according to Marius Wernig, "it will take a lot of work."
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01.02.2012