Shah, Nirao M. and Anderson, David J. (1997) Integration of multiple instructive cues by neural crest stem cells reveals cell-intrinsic biases in relative growth factor responsiveness. Proceedings of the National Academy of Sciences of the United States of America, 94 (21). pp. 11369-11374. ISSN 0027-8424 http://resolver.caltech.edu/CaltechAUTHORS:SHApnas97
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Growth factors can influence lineage determination of neural crest stem cells (NCSCs) in an instructive manner, in vitro. Because NCSCs are likely exposed to multiple signals in vivo, these findings raise the question of how stem cells would integrate such combined influences. Bone morphogenetic protein 2 (BMP2) promotes neuronal differentiation and glial growth factor 2 (GGF2) promotes glial differentiation; if NCSCs are exposed to saturating concentrations of both factors, BMP2 appears dominant. By contrast, if the cells are exposed to saturating concentrations of both BMP2 and transforming growth factor ß1 (which promotes smooth muscle differentiation), the two factors appear codominant. Sequential addition experiments indicate that NCSCs require 48-96 hrs in GGF2 before they commit to a glial fate, whereas the cells commit to a smooth muscle fate within 24 hr in transforming growth factor ß1. The delayed response to GGF2 does not reflect a lack of functional receptors; however, because the growth factor induces rapid mitogen-activated protein kinase phosphorylation in naive cells. Furthermore, GGF2 can attenuate induction of the neurogenic transcription factor mammalian achaete-scute homolog 1, by low doses of BMP2. This short-term antineurogenic influence of GGF2 is not sufficient for glial lineage commitment, however. These data imply that NCSCs exhibit cell-intrinsic biases in the timing and relative dosage sensitivity of their responses to instructive factors that influence the outcome of lineage decisions in the presence of multiple factors. The relative delay in glial lineage commitment, moreover, apparently reflects successive short-term and longer-term actions of GGF2. Such a delay may help to explain why glia normally differentiate after neurons, in vivo.
|Additional Information:||© 1997 by the National Academy of Sciences. Communicated by Melvin I. Simon, California Institute of Technology, Pasadena, CA, August 5, 1997 (received for review June 18, 1997). We thank Scott Fraser, Paul Sternberg, Kai Zinn, Paul Patterson, Sean Morrison, and Ron McKay for helpful suggestions and comments on an early version of the manuscript. This work was supported by the National Institutes of Health and a grant from the Muscular Dystrophy Association. D.J.A. is an Investigator of the Howard Hughes Medical Institute. The publication costs of this article were defrayed in part by page charge payment. This article must therefore be hereby marked "advertisement" in accordance with 18 U.S.C. §1734 solely to indicate this fact.|
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|Deposited By:||Tony Diaz|
|Deposited On:||27 Mar 2008|
|Last Modified:||26 Dec 2012 09:54|
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