Deviating from the well travelled path: precursor cell migration in the pathological adult mammalian brain

The presence of both neural and glial precursor cells in the adult central nervous system (CNS) and the capacity of these cells to migrate through this mature structure to areas of pathological damage and injury raises hope for the development of new therapeutic strategies to treat brain injury and disease. Although at present time, the compensatory neurogenesis described after various types of brain pathologies appears to be modest, the development of a strategy promoting the directed mobilization and phenotypic induction of endogenous precursor cells to areas of neural cell loss remains of high interest. The development of such a strategy however is currently thwarted by a limited understanding of the process and factors influencing precursor cell migration. In this review, we will discuss the current knowledge around precursor cell migration in the pathological adult brain with particular focus on the response and fate of precursor sub-populations to neural cell loss and the role of the inflammatory system in mediating precursor cell migration. Through this discussion we will identify particular areas in which further detailed research is required in order to expand our current understanding and aid in the eventual development of a novel therapeutic application.