Notch effect steers stem cells into nervous system

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The Notch effect steers stem cells into cells of the nervous system

http://www.news-medical.net/?id=17347

Stem cell scientists at the University of Edinburgh have discovered that Notch,

a protein first discovered more than 80 years ago in the fruit fly, directs

unspecialized embryonic stem cells to become cells of the nervous system.

These unexpected findings pave the way for using lab-grown cells to model

disease and test the effects of new drugs, and are published online this week in

the open-access journal PLoS Biology.

Embryonic stem cells have the potential to make all 200 cell types in the body.

The challenge is to restrain this diversity and uncover the signals that commit

stem cells to a single specialised function. Sally Lowell and her colleagues

have now established that Notch gives embryonic stem cells the critical push

towards becoming cells of the nervous system.

The researchers show that when Notch is activated in embryonic stem cells, up to

90% of the cells in the dish become nerve cells. In any colony of embryonic stem

cells, under normal conditions, many never become cells of the nervous system:

they spontaneously change into other cell types or remain as embryonic stem

cells.

The Notch effect can be observed in both mouse and human embryonic stem cells,

and can be created without any recourse to genetic engineering - all it takes is

the presence of Notch activating signals in the cells that stem cells grow on.

As individual embryonic stem cells become specialised, they communicate with

those around them. Notch is a major means of communication, and has, according

to Dr Lowell, " a domino effect: once it is switched on in a small group of

cells, it sets off a wave of Notch activation in neighbouring cells, directing

them all to become cells of the nervous system. "

This research has far-reaching implications for other aspects of stem cell

research. Dr Lowell adds, " We expect our findings to shed light on how to make

other types of cell, such as muscle or pancreatic cells. If we can identify the

processes that Notch blocks in embryonic stem cells we will have a handle on how

to get them started, and so drive embryonic stem cells to become other types of

cell that are more difficult to grow in the lab " .

Says Professor Austin , leading the Edinburgh team and coordinating the

EuroStemCell consortium, " This discovery gives us another method to generate

pure populations of nerve cells - so important for drug screening, disease

modelling and potential cell therapies. As in stem cell colonies, communication

between EuroStemCell researchers has been crucial to this discovery. Our work

would not have been possible without information and materials from colleagues

in Cambridge, Paris and Stockholm. "

This research was supported by EuroStemCell, the BBSRC, the MRC and The Wellcome

Trust.

http://www.iscr.ed.ac.uk

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