Heterogeneity of Mouse Astrocytes – from Genes to Brain Functions

Astrocytes are one of the main glia populations in all regions of the central nervous system (CNS). Depending on their origin, location and shape, they have been given different names: protoplasmic astrocytes are regarded as the typical form of the grey matter, while fibrous astrocytes are found in white matter. In addition, Bergmann glia are known as the radially-shaped astrocytes of the cerebellum, Müller cells are respective isoforms in the retina and tanycytes are astroglial cells lining the third ventricle. A common feature of all these cells in the different CNS regions is their contact to pre-and postsynaptic neuronal terminals. Such perisynaptic astroglial processes are important detectors of neuronal activity and regulators of synaptic transmitter levels. In addition, the astroglial subtypes have special endfoot structures with contacts to supporting blood vessels. As such astroglia functionally and structurally connect the brain vasculature with neural circuits.

Studies of recent years have shown how specific genes determine regional identity. In particular, transmitter receptors and transcription factors are not only found to be selectively expressed on astroglial cell populations, transcriptomic and epigenomic as well as functional analyses generate a novel emerging view how bidirectional neuron-glia interactions contribute to region-specific brain functions. Focusing on cortical astrocytes and cerebellar Bergmann glia, I will discuss how mouse genetics, physiological and behavioral analysis in combination with molecular approaches at the population level help to understand the most complex organ of our body.