Project number 9

Elucidating the Ca2+ code of astrocyte function

Astrocytes are one of the major cell types in the central nervous system. Astrocytes possess many thin processes, which radiate from the cell body and contact neurons or blood vessels. Astrocytes modulate synaptic transmission and blood flow through the release of distinct bioactive molecules (in response to neuronal activity).
A key second messenger in this response is intracellular Ca2+, which increases upon astrocyte activation. To date, most studies have focused on bulk Ca2+ increases in the cytoplasm as a physiological effector. However, whether this represents the whole astrocyte response is questionable. Given the complexity of astrocyte anatomy and function, the potential use of multiple neurotransmitter systems to trigger astrocyte activity, the precise location of Ca2+ release (in relation to Ca2+ sensitive molecular machinery), and duration of the Ca2+ signal, it is likely that there is an intracellular ‘Ca2+ code’ which allows exquisite control over cell function.
Using in vivo imaging in awake behaving mice, our groups have recently found evidence for multiple modes of Ca2+ signaling in primary visual cortex in response to visual stimulation.  The Ca2+ signals generated contain information on both the sensory input and behavioral state of the animal.
We now wish to appoint a highly motivated student, who will work at the interface of both labs (in a roughly 50:50 time split). Taking advantage of access to unique genetic tools for in vivo manipulation of astrocytes (Holt lab) combined with dual color in vivo imaging (to record from both astrocytes and neurons) (Bonin lab), the student will investigate the physiological basis of the astrocytic Ca2+ code and its implications for signal processing in the visual system.

Keywords
astrocyte, in vivo imaging, visual cortex, pharmacology, genetics

Supervisors
Matthew Holt, VIB Center for the Biology of Disease, KU Leuven, Leuven
Vincent Bonin, Neuro-Electronics Research Flanders, Imec, Leuven