Stem cells self renew, reveals study
Researchers from the EU-funded EuroStemCell project have shown for
the first time that mouse embryonic stem cells are able to self-renew
without the natural culture materials that scientists have so far
used to maintain them and grow stem cell lines. This discovery, which
was recently published in the journal Nature, contradicts previously-
held views and could have wide-ranging implications for stem cell
research.
Mouse embryonic stem]cells can self-replicate without external
instruction implies that they are intrinsically programmed to self-
renew
© Jason Wray (EuroStemCell)
Mouse embryonic stem cells are derived and grown using various
combinations of culture materials such as feeder cells, conditioned
media, hormones and serum extracts. Previously, it was believed that
these materials provided the signals and instructions to stem cells
to maintain their undifferentiated `blank' state. Without these
materials, it was thought that stem cells would specialise to become
whatever type of cell they were prompted to become.
Cells still need to be grown in a culture giving them the sugars and
proteins needed to stay alive. However, the researchers were able to
show that embryonic stem cells produce their own signalling molecules
and that these signals are the key driving force behind
differentiation.
When one of the cells' own signalling molecules, FGF (Fibroblast
Growth Factor) 4, is eliminated or blocked, the cells can remain in
their undifferentiated state indefinitely, the researchers
discovered. They demonstrated this by applying small molecules that
would block the action of FGF4.
`That ES [embryonic stem] cells can self-replicate without external
instruction implies that they are intrinsically programmed to self-
renew. The new culture conditions will help us to understand the
nature of the pluripotent state and how it might be manipulated to
produce specialised cells in the laboratory,' explains, Jason Wray of
the Wellcome Trust Centre for Stem Cell Research, and one of the
authors on the paper.
The research is expected to be useful for the derivation of embryonic
stem cells from other animals.
'We believe the process we discovered in mice may facilitate the
derivation of embryonic stem cells from species like pigs, cows or
other large animals, which have not been done before,' Qi-Long Ying,
the lead author of the paper and now assistant professor of cell and
neurobiology at the University of Southern California (USC). 'If
deriving embryonic stem cells from cows, for instance, is possible,
then perhaps in the future cows might be able to produce milk
containing medicines.'
A better understanding of what controls differentiation in mouse
embryonic stem cells should also allow the work that has so far taken
place only with mouse embryonic stem cells to be replicated in human
embryonic stem cells.
`Last year it was shown that established human `ES' cells are more
similar to mouse `Epi-stem cells', which correspond to a later stage
of development. We have reason to believe that what we have observed
in mice will read across to other mammals and that the new culture
conditions we have established may allow us to transfer our
experience and techniques from animal models to human,' explains
Jason Wray.
The discovery is expected to have major implications for large scale
production of specialised cells, such as brain, heart muscle and
insulin producing cells, for future therapeutic use.
http://ec.europa.
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StemCells subscribers may also be interested in these sites:
Children's Neurobiological Solutions
http://www.CNSfoundation.org/
Cord Blood Registry
http://www.CordBlood.com/at.cgi?a=150123
The CNS Healing Group
http://groups.yahoo.com/group/CNS_Healing
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