Year 1

Overall, our biggest breakthrough this year has been the identification of a link among the sugars on the cell surface, a label free electrical measure reflecting the type of mature cell the stem cells will become (membrane capacitance), and stem cell fate potential, or the ability of the cell to form a particular type of mature cell. Stem cells generate mature, functional cells after proteins on the cell surface interact with cues from the environment encountered during development or after transplantation. Thus, these cell surface proteins are critical for directing transplanted stem cells to form the appropriate types of cells to treat injury or disease. A key modification regulating cell surface proteins is glycosylation, which is the addition of sugars onto proteins and has not been well studied in neural stem cells. Our project focuses on a major unsolved problem in the neural stem cell field: do different proteins coated with sugars on the surfaces of cells in this lineage (neuron precursors, NPs and astrocyte precursors, APs) determine what types of mature cells will form? We hypothesize key players directing cellular decisions are glycosylated proteins controlling how precursors respond to extracellular cues. This year on the project, we found a particular glycosylation pathway that adds highly branched sugars regulates cell surface properties and controls the decision to form either a neuron or an astrocyte. In the next year of the project, we will explore this pathway further and perform experiments to identify the proteins on the cell surface important for determining the formation of either mature neurons or astrocytes. By answering these questions, we will better understand the regulation of NPs and APs, which will improve the use of these cells to treat brain and spinal cord diseases and injuries.