In a high-throughput screening of fluorescent molecules, the fluorescent
compound CDr3 stained neural stem cells the most brightly and specifically.
The screening of thousands of fluorescent molecules has revealed a
specific label for neural stem cells
Neural stem cells are the
precursors of cells in the nervous system. As well as being crucial for early
development, they are present throughout life, contributing to flexibility and
repair of the nervous system. As such, they can be used to study the brain, and
may offer new ways of treating neurological disease.
Current techniques for
identifying and labeling live neural stem cells use antibodies to detect
specific cell-surface molecules. Small fluorescent molecules, which are
commonly used to visualize the locations and movements of molecules and cells,
may offer a more convenient and safer alternative.
Young-Tae Chang at the A*STAR
Singapore Bioimaging Consortium and co-workers have now identified a
fluorescent compound that specifically labels neural stem cells by binding to
an intracellular protein1. The molecule, named CDr3, was singled out for its
selective labeling of neural stem cells after testing thousands of fluorescent
compounds from a ’Diversity Oriented Fluorescence Library’, or DOFL.
“A DOFL is a collection of
intrinsically fluorescent low molecular weight compounds which have been
synthesized, purified and characterized in our lab,” says co-author Seong-Wook
Yun. “We have generated more than 10,000 DOFL compounds so far, each with different
chemical and biological properties.”
The researchers narrowed down the
number of potentially useful molecules by assessing how strongly they labeled
stem cells, and finally determined that CDr3 stained them the most selectively
and brightly (see image). They confirmed the specificity of labeling by
incubating CDr3 with different cell types and showing that it only stained
neural stem cells. Growing stem cells in the presence of CDr3 also showed that
it does not affect their survival or division.
A combination of molecular
biology techniques revealed that CDr3 labeled the cells by binding to a neural
stem cell-specific protein called FABP7. This is found inside the cell, unlike
other labeling targets. “Conventionally, live neural stem cells have been
identified by detecting cell surface molecules,” explains Yun. “However, these
molecules are also highly expressed in other types of cells. FABP7 is a
specific intracellular marker of neural stem cells.”
Labeling of neural stem cells
with CDr3 not only allowed them to be identified, but also to be separated from
other types of cells. According to Yun, this is important for practical
applications.
“Detection and isolation of live
neural stem cells from heterogeneous cell populations is a key technology, not
only for basic research but also for the development of cell-based therapeutics
and drug development,” he says.
The A*STAR-affiliated researchers
contributing to this research are from the Singapore Bioimaging Consortium and
the Genome Institute of Singapore
References
- Yun, S.-W., Leong, C., Duanting, Z., Tan, Y. L.,
Lim, L. et al. Neural stem cell specific fluorescent chemical probe binding to
FABP7. Proceedings of the National Academy of Sciences USA 109, 10214–10217
(2012). |article
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