“Studying the roles of dark microglia in aging and neurodegenerative diseases via cutting-edge electron microscopy,” presentation by Dr. Eve Tremblay, Canada Research Chair (Tier II) in Neurobiology of Aging and Cognition, Associate Professor, Division of Medical Sciences, University of Victoria.
Abstract:
Microglia, which are the brain immune cells, were shown over the last decade to play important beneficial roles, notably in the remodeling of the neuronal circuits that is required for learning, memory and the adaptation to the environment across the lifespan. In my presentation, I will discuss our recent characterization of an ultrastructurally distinct microglial subtype that is predominantly associated with pathological states, using a combination of transmission electron microscopy, array tomography and focused-ion beam scanning electron microscopy with immunostaining and 3D reconstruction. The dark microglia are rare in healthy young adults, but become highly prevalent upon chronic stress, viral infection, aging, and Alzheimer’s disease pathology, where they account for two-thirds of the typical microglial population. These cells are encountered in various brain regions, including the hippocampus, which is important for cognition. Surprisingly, we also found the dark microglia to be very abundant during normal brain development, in the first postnatal weeks when synaptic pruning mainly takes place. The findings indicate that dark microglia could represent a subset of cells that become stressed as a result of their hyperactive involvement with the remodeling of neuronal circuits across development, stress-induced plasticity, aging, and neurodegenerative disease.
Zoom Presentation: Monday June 22, 2020 from 2:30-3:30 pm