MGE Enhancers to Select for Interneuron Precursors Produced from Human ES Cells

Large numbers of California residents are stricken with severe medical disorders affecting the function of their brain. These include epilepsy, Parkinson’s Disease, Alzheimer’s Disease, Huntington’s Disease, Autism and Schizophrenia. For instance, a recent report from the Center for Disease Control and Prevention [www.cdc.gov/epilepsy/] estimates that 1 out of 100 adults have epilepsy. In California, epilepsy is one of the most common disabling neurological conditions, with approximately 140,000 affected individuals. The annual cost estimates to treat epilepsy range from $12 to $16 billion in the U.S. Currenlty up to one-third of these patients are not receiving adequate treatment, and may benefit from a cell-based transplantation therapy that we are currently exploring with our work in mice. There are now viable experimental approaches to elucidate the genetic and molecular mechanisms that underlie these neuropsychiatric disorders through the generation a stem cells, called iPS cells, from the skin of patients. Scientists are now challenged to develop methods to program iPS cells to become the specific types of brain cells that are most relevant to each specific brain disease. For instance, there is evidence that defects in cortical interneurons contribute to epilepsy, autism and schizophrenia. The experiments proposed in this grant application aim to understand basic mechanisms that underlie the development of cortical interneurons. We are discovering regulatory elements (called enhancers) in the human genome that control gene expression in developing interneurons. Our experiments will help us understand fundamental mechanisms that govern development of these cells. Furthermore, we have designed experiments that harness these enhancers to drive the production of specific subtypes of these cells from human stem cells. This will open the door to making these types of neurons from iPS cells to study human disease, and potentially to the production of these neurons for transplantation into patients whose interneurons are deficient in regulating their brain function. Furthermore, the approach we describe is general and readily applicable to the generation of other brain cells. Thus, the results from these studies will provide essential and novel basic information for understanding and potentially treating severe brain disorders.