Tuesday, October 4, 2011

Cellular transformation may aid in creating tissues

Currently, stem cells are used to artificially create cells of interest, by guiding them towards a certain cellular fate. A molecule, which functions as a modulator of gene transcription, shows that it is possible to convert a cell directly from one type to another, without the need for stem cells. By showing that cells can be directly transformed into other cell types, a feat that was long thought to be only possible in stem cells, scientists have new options to create tissue that can be used for treatment.

In their experiments, certain cells from the blood were transformed from one type to another. For this, a transcription factor called C/EBPα was needed that changes the gene expression of cells: some genes are switched on, while others are switched off. The change in expression pattern seemed to change the cell type, the scientists noted after genetic analysis. Normally, when cells differentiate, they have to be reversed to a primitive stage. From the experiments could be concluded that the typical genes involved with this process, called retrodifferentiation, were absent, which lead to the conclusion that the cells transformed directly, without going back to a more primitive stage.

To create a certain cells, for example neurons, scientists often make use of stem cells. These primitive cells have the capability to differentiate into a wide variety of cells, and we have found several ways to control this process. To make things even easier, it is possible to transform already differentiated adult cells back into stem cells, without the need to harvest them from embryos. However, this process costs a lot of time and effort. Therefore, being able to transform adult cells directly into a desired cell type can make creating tissue easier.

We try making cells and tissues ourselves, because in some cases the body is unable to restore tissue after damage. Neurons from the nervous system are the most famous example. These cells rarely grow back, which makes brain and spinal cord damage often permanent. Patients that suffered from a stroke often find themselves with permanent loss of function, something that could possibly be reversed if we find ways to create and administer the cells that make up the lost tissue.

A lot of experimental therapies involve stem cells, but if the scientists find a way to use their proof of concept for more cell types, it would save a lot of time and hassle to create cells of choice. It might also be safer, as misguided stem cells can transform into something different, which possibly involves tumour formation.

It remains to be seen whether this concept works for all cells. During the experiments, certain blood cells were transformed into another type of cell that resides in the blood. Because they are of the same lineage, they are not as different as a liver cell compared with a brain cell, for example. However, this proof of concept shows direct transformation is possible, and paves the way for new studies that aim to investigate how we can transform more cell types, in order to more easily create the cells and tissues we want for treatment. 

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