Molecular and functional features of synucleinopathy-associated astrocytes

Astrocyte (AC) involvement is a common neuropathological feature in human synucleinopathy-associated neurodegeneration. However, our understanding of the in vivo characteristics of reactive ACs in synucleinopathy remained limited. Here we report the transcriptomic and functional features of a unique synucleinopathy-associated AC (SAA) subtype in a mouse model. SAAs share a convergent transcriptomic state across synucleinopathy-laden brain regions, and are at least partially reliant on microglia for their phenotypic maintenance in vivo. Intravital imaging revealed that an upregulation of the excitatory amino acid transporter 2 (EAAT2) in synucleinopathy-affected ACs is associated with depressed neuronal activities. This is potentially mediated via increased AC glutamate uptake, as pharmacological induction of EAAT2 reproduced the same effect. With cross-species comparative analysis, we showed that the core SAA transcriptomic features are present in human aged and synucleinopathy-affected midbrain ACs, while important distinct characteristics also exist. Collectively, our results uncovered complex reactive AC changes that likely play important adaptive roles in synucleinopathy. Mouse brain frontal cortex and midbran two regions from Huα-Syn(A53T) and wildtype mice group(3 mice each group) were acquired to perform scRNAseq.