Small Molecule–Based Approaches to Adult Stem Cell Therapies

There is considerable interest in the development of stem cell–based strategies for the treatment of a broad range of human diseases, including neurodegenerative, autoimmune, cardiovascular, and musculoskeletal diseases. To date, such regenerative approaches have focused largely on the development of cell transplantation therapies using cells derived from pluripotent embryonic stem cells (ESCs). Although there have been exciting preliminary reports describing the efficacy of ESC-derived replacement therapies, approaches involving ex vivo manipulated ESCs are hindered by issues of mutation, immune rejection, and ethical controversy. An alternative approach involves direct in vivo modulation or ex vivo expansion of endogenous adult stem cell populations using drug-like small molecules. Here we describe chemical approaches to the regulation of somatic stem cell biology that are yielding new biological insights and that may ultimately lead to innovative new medicines.