The discovery that astrocytes are important for neuronal maturation, or neurogenesis, was reported in the May 2, 2002, issue of the journal Nature by Howard Hughes Medical Institute investigator Charles F. Stevens and colleagues Fred H. Gage and HHMI research associate Hong-jun Song at The Salk Institute.
Neurons are the key information-carrying cells in the central nervous system. All neurons, as well as other types of brain cells, arise from immature neural stem cells, which have the potential to develop into any kind of cell in the central nervous system.
According to Stevens, astrocytes have not traditionally been thought to be involved in neurogenesis. "Astrocytes, so-named because of their starlike shape, are glial cells, a term which is derived from the Latin word for 'glue,'" explained Stevens. "They fill in the space between neurons, and they have long been known to have a supportive role, which includes taking up neurotransmitters released by neurons. They also maintain the extracellular environment with the right concentrations of chemicals to support neurons."
Recently, however, evidence emerged that astrocytes might actually be "instructing" stem cells about which developmental pathway to select, said Stevens. For example, Stevens and his colleagues reported in a previous research article that adult neuronal stem cells proliferated more readily when they were cultured with astrocytes rather than on a layer of fibroblast cells.
Contact: Jim Keeley
Howard Hughes Medical Institute