Role of Astrocytes in Sculpting Neuronal Circuits in the Drosophila CNS: A Dissertation

The nervous system is composed of neurons and glia. Glial cells have been neglected and thought to have only a supportive role in the nervous system, even though ~60% of the mammalian brain is composed of glia. Yet, in recent years, it has been shown that glial cells have several important functions during the development, maintenance and function of the nervous system. Glial cells regulate both pre and post mitotic neuronal survival during normal development and maintenance of the nervous system as well as after injury, are necessary for axon guidance, proper axon fasciculation, and myelination during development, promote synapse formation, regulate ion balance in the extracellular space, are required for normal synaptic function, and have immune functions in the brain. Although glia have crucial roles in nervous system development and function, there are still much unknown about the underlying molecular mechanisms in glial development, function and glial-neuronal communication. Drosophila offers great opportunity to study glial biology, with its simple yet sophisticated and stereotypic nervous system. Glial cells in flies show great complexity similar to the mammalian nervous system, and many cellular and molecular functions are conserved between flies and mammals. In this study, I use Drosophila as a model organism to study the function of one subtype of glia: astrocytes. The role of astrocytes in synapse formation, function and maintenance has been a focus of study. However, their role in engulfment and clearance of neuronal debris during development remains unexplored.