GNAI1 and Huntington disease: 18,120,189 Furthermore, by identifying astrocyte Gi-GPCRs as upstream regulators of the molecular changes within HD astrocytes, it was found that chemogenetic activation of the Gi-DREADD hM4Di could restore astrocyte morphology, early aspects of behavioral decline in HD model mice, and fast synaptic excitation onto MSNs in a TSP-1 dependent manner.