Adult neural stem cells and their role in brain pathology.

Stem cells are multipotent cells that can give rise to a differentiated progeny as well as self-renew. The balanced coordination of these two stem cell fates is essential for embryonic development and tissue homeostasis in the adult. Perturbed stem cell function contributes significantly to a variety of pathological conditions, eg impaired self-renewal capacity due to cellular senescence contributes to ageing, and degenerative diseases or impaired stem cell differentiation by oncogenic mutations contribute to cancer formation. This review focuses on the molecular mechanisms involved in regulating the normal function of neural stem cells in the adult mammalian brain and on the involvement of these cells in brain pathology.