Neurotoxic versus neuroprotective astrocytes: is it that simple?

Reactive astrocytes are commonly divided into two categories, A1 and A2, based on transcriptomics. In this classification, A1 astrocytes show a neurotoxic phenotype, whereas A2 astrocytes demonstrate neuroprotective properties. Carole Escartin, PhD, Centre National de la Recherche Scientifique, Université Paris Saclay, Fontenay-aux-roses, France, highlights the limitations of this binary division, given the morphological, molecular, and functional heterogeneity of reactive astrocytes demonstrated in recent research. Studies at the single cell level have shown that reactive astrocytes do not fall into two fixed categories but can take on many context-dependent states and are highly plastic. For this reason, a recently published consensus statement from over 80 experts advocates for astrocyte research to include assessment of multiple molecular and functional parameters. As of yet, it is unclear if fixed categories of astrocytes exist and if so, how to define them. This interview took place at the Alzheimer's Association International Conference (AAIC) 2022 in San Diego, CA.