Heterogeneity， Formation of Neurosphere， and Re-evaluation of Neurosphere Assay

Abstract: Neural stem cell can be grown in vitro as the free-floating structure known as neurosphere. Based on the conception that neurospheres are the clonal cell clusters of neural stem cells， neurosphere assay has been widely used in neurobiological research for a long time. However， it is reported recently that most cells in neurospheres are not bona fide neural stem cells. Heterogeneity characterizes not only the neurospheres but the neurosphere-forming cells as well. Besides of cell proliferation， cell reaggregation and neurosphere mergence also play their roles in the formation of neurospheres. Moreover， several important molecules take part in the process. Therefore， before therapeutic applications of neurospheres are finally reached， a more complete understanding of neurosphere assay should be needed， as the sensitivity and specificity of the assay should be well re-defined， and the usefulness of the assay has to be re-examined carefully.

CSTR: 32200.14.cjcb.2008.01.0013