Chemogenetic Control of Striatal Astrocytes Improves Parkinsonian Motor Deficits in Mice

Parkinson's disease (PD) is characterized by the degeneration of dopaminergic nigrostriatal inputs, which causes striatal network dysfunction and leads to pronounced motor deficits. Recent evidence highlights astrocytes as a potential local source for striatal neuromodulation. There is substantial evidence for norepinephrine-mediated recruitment of cortical astrocyte activity during movement and locomotion. However, it is unclear how astrocytes in the striatum, a region devoid of norepinephrine neuromodulatory inputs, respond during locomotion. Moreover, it remains unknown how dopamine loss affects striatal astrocyte activity and whether astrocyte activity regulates behavioral deficits in PD. We addressed these questions by performing astrocyte-specific calcium recordings and manipulations using in vivo fiber photometry and chemogenetics. We find that locomotion elicits astrocyte calcium activity over a slower timescale than neurons. Acute pharmacological blockade of dopamine receptors only moderately reduced locomotion-related astrocyte activity. Yet, unilateral dopamine depletion significantly attenuated astrocyte calcium responses. Chemogenetic stimulation of G_i-coupled receptors partially improved this functional astrocyte deficit in dopamine-lesioned mice. In parallel, chemogenetic manipulation restored asymmetrical motor deficits and moderately improved open-field exploratory behavior. Together, our results establish a novel role for functional striatal astrocyte signaling in modulating motor function in PD and highlight non-neuronal targets for potential PD therapeutics.