Differentiation versus plasticity: fixing the fate of undetermined adult stem cells.

Adult mesenchymal stem cells own a considerable plasticity, which enables them to respond to various extra- and intracellular cues and exert, at least partially, various differentiation pathways. Recently, we have shown that multipotent adult stem cells (MASCs) derived from the mouse bone marrow (mBM-MASCs) consist of distinct cell populations that have similar differentiation abilities but differ in the expression of several stem cell markers. Despite their remarkable developmental potential MASCs seem to miss crucial components to complete specific differentiation programs necessary to acquire a fully functional phenotype. A thorough analysis of active and inactive regulatory circuits in multipotent adult stem cells might lead the way to a controlled programming of these cells and rational therapeutic applications.