7 Neurospheres

Abstract

Neural stem cells (NSCs) are ideal candidates to study fundamental cell biological and developmental questions under defined experimental conditions and to lay the foundation for cell-based therapies for neurological diseases. Somatic stem cells, such as NSCs, are primordial cells that generate all major cell types of a given organ during development, maintain homeostasis and integrity throughout life, and may initiate repair following injury. Stem cells have to make decisions as to whether they generate identical daughter cells by symmetric cell division or give rise to a more differentiated progeny by asymmetric cell division. It is conceivable to believe that NSCs and the regulation of their function (cell autonomous as well as non-cell autonomous) are complex and precisely controlled. In addition, since rapid phenotype changes are in the nature of stem cells, this adds another dimension of challenge to the work with NSCs. Therefore, the successful culture, controlled expansion, and ex vivo manipulation of bona fide stem cells are still ambitious tasks that necessitate continued improvement as our knowledge about stem cell biology increases. Better control and understanding of cell growth and the conditions that promote this growth, as well as differentiation of NSCs, are crucial elements before large-scale applications of stem cell therapy can be moved to the clinic.

Traditionally, because of the difficulties in growing neuronal cells, the NSC field has emerged from studies with immortalized cell lines. These cell lines were derived from spontaneously occurring tumors or were immortalized by genetic manipulation and introduction of oncogenes into neuronal...