About the speaker:

J. Heller is a neurobiochemist. He obtained his PhD in 2015 from the University of Cambridge, UK, before moving to the Queen Square Institute of Neurology at University College London, UK, as a Research Associate to work with Prof Dmitri Rusakov. In 2018, Dr Heller joined the Royal College of Surgeons in Ireland and the SFI Research Centre FutureNeuro as a Marie Skłodowska-Curie Fellow. In December 2020, Dr Heller started his research group in the School of Biotechnology, Dublin City University, Ireland. Current research interests in the group are focused on using SMLM to understand how astrocytes change in disease and how these cells can be targeted as novel therapeutic intervention to treat neurological and neuropsychiatric diseases.

Abstract:

Astrocytes play an active role in shaping and maintaining neuronal circuits. In addition to their long-established role in extracellular potassium buffering and glutamate uptake, these cells can also regulate the activity of local synaptic circuits through secretion and clearance of neurotransmitters. Whilst the molecular signal exchange between astroglia and synapses occurs in a highly heterogeneous microenvironment on the nanoscale, the spatial subcellular distribution of the underlying molecular machineries remains poorly understood.

We have therefore employed SMLM to visualise the 3D positions of neurotransmitter receptors and transporters in astrocytes. We localised cytoskeletal proteins as well as clusters of receptors and transporters in astrocytic and neuronal membranes in fixed cultured cells and in brain slices. Moreover, we assessed the positional relationship between synapses and astroglial receptors and transporters through multi-colour imaging. We determined that astroglial coverage of excitatory synapses is altered in different conditions compatible with long-term synaptic potentiation and depression, providing further evidence for the role of astrocytes in shaping synaptic transmission.