Grant: CIHR Fellowship

Astrocytes are nervous system cells that carry out many functions such as coordinating brain development, regulating the activity of neural circuits, and repairing the brain when it is damaged. Astrocytes are involved in every disease that affects the brain. Understanding astrocyte biology could therefore lead to the development of new treatments for a wide variety of diseases. Evidence from gene expression profiling suggests the existence of multiple subpopulations of astrocytes. However, a major question that has proven difficult to answer is whether subpopulations of astrocytes perform distinct functions. To answer this question, we have developed new tools that make use of genetic differences in astrocyte subpopulations to allow us to experimentally study them in mice. Since astrocytes have many functions, and some of them are only apparent in certain contexts, I will use these new tools to study the unique functions of astrocyte subpopulations in three contexts: brain development, normal function, and repair. In mice, I will selectively eliminate certain astrocyte subpopulations across these contexts to reveal if they have distinct functions. First, I will examine if astrocyte subpopulations contribute differently to brain development, as measured by the formation of synaptic connections and the formation of blood vessel networks. Next, I will determine if astrocyte subpopulations have different roles in regulating brain circuit function or behaviour. Finally, I will examine the roles of astrocyte subpopulations in repairing the brain and helping to recover lost functions after stroke. By defining the unique functions of astrocyte subpopulations, this research will improve our fundamental understanding of the brain's most common glial cell type. Moreover, these findings may provide insights into how we can better treat disease. For example, we might learn that promoting the function of one astrocyte subpopulation can improve recovery from stroke.