20 April 2009

Direct reprogramming of cells

Scientists "reprogrammed" cells using RNA
Dmitry Safin, "Kompyulenta" 

A group of researchers from the University of Pennsylvania (USA) turned (reprogrammed") a neuron into an astrocyte by introducing a matrix RNA (mRNA) of the appropriate type into the cell.

"The novelty of this approach is that we did not turn the original cell into a pluripotent one capable of developing in several directions," explains Professor James Eberwine. "We managed to eliminate the intermediate stage." Scientists have called their technology "transcriptome induced phenotype remodeling" (transcriptome induced phenotype remodeling).

The essence of the process is as follows: by phototransfection (this method is used to create holes in the cell membrane that close over time), researchers "transplant" astrocyte mRNA molecules to a neuron, and the number of transferred molecules is approximately twice the number of the original ones (200 thousand versus 100). The picture shows a mouse neuron into which mRNA molecules are transferred (the image was obtained by the authors of the study).

The resulting effect resembles the action of a virus: astrocyte mRNAs that suppress "native" mRNAs begin to be used during translation to synthesize proteins corresponding to the invader cell. The resulting proteins then affect the expression of genes in the nucleus of the neuron, and the astrocyte genes are "turned on".

During the experiment, scientists observed changes in the cell's RNA, its shape and physiology. "Let's put it this way: we got cells similar to astrocytes," says Mr. Eberwine. – They no longer resemble neurons at all, however, they have not yet acquired a characteristic stellate shape; at the same time, a set of proteins and features of physiology are given out in them by astrocytes. We observe the first changes after a week, and these effects persist until the cell dies."

The full version of the report will be published in the journal Proceedings of the National Academy of Sciences.

Prepared based on the materials of PhysOrg.

Portal "Eternal youth" www.vechnayamolodost.ru20.04.2009

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