Project description:Given that the striatum is a large, multifunctional nucleus, we next aimed to understand where astrocyte subtypes exist in the striatum at a single-cell resolution using MERFISH. We reproducibly identified the seven astrocyte subtypes, some of which were dorsal (A1, A7), medial (A3, A6) or ventral dominant (A4).
Project description:Astrocytes tile the central nervous system, but their functions in neural microcircuits in vivo and their roles in mammalian behavior remain incompletely defined. We used 2-photon laser scanning microscopy (2PLSM), electrophysiology, MINIscopes, RNA-seq and a new genetic approach to characterize the effects of reduced striatal astrocyte Ca2+ signaling in vivo. In wild type mice, reducing striatal astrocyte Ca2+-dependent signaling increased repetitive self-grooming behaviors by altering medium spiny neuron (MSN) activity. The mechanism involved astrocyte-mediated neuromodulation mediated by ambient GABA and was corrected by blocking astrocyte GABA transporter 3 (GAT-3). Furthermore, in a mouse model of Huntington’s disease, dysregulation of GABA and astrocyte Ca2+ signaling accompanied excessive self-grooming, which was relieved by blocking GAT-3. Assessments with RNA-seq revealed astrocyte genes and pathways regulated by Ca2+ signaling in a cell autonomous and non-cell autonomous manner, including Rab11a, a regulator of GAT-3 functional expression. Thus, striatal astrocytes contribute to neuromodulation controlling obsessive-compulsive-like behavior in mice.
Project description:Astrocytes tile the central nervous system, but their functions in neural microcircuits in vivo and their roles in mammalian behavior remain incompletely defined. We used 2-photon laser scanning microscopy (2PLSM), electrophysiology, MINIscopes, RNA-seq and a new genetic approach to characterize the effects of reduced striatal astrocyte Ca2+ signaling in vivo. In wild type mice, reducing striatal astrocyte Ca2+-dependent signaling increased repetitive self-grooming behaviors by altering medium spiny neuron (MSN) activity. The mechanism involved astrocyte-mediated neuromodulation mediated by ambient GABA and was corrected by blocking astrocyte GABA transporter 3 (GAT-3). Furthermore, in a mouse model of Huntington’s disease, dysregulation of GABA and astrocyte Ca2+ signaling accompanied excessive self-grooming, which was relieved by blocking GAT-3. Assessments with RNA-seq revealed astrocyte genes and pathways regulated by Ca2+ signaling in a cell autonomous and non-cell autonomous manner, including Rab11a, a regulator of GAT-3 functional expression. Thus, striatal astrocytes contribute to neuromodulation controlling obsessive-compulsive-like behavior in mice.
Project description:The Khakh laboratory used astrocyte selective AAVs expressing Rpl22-HA and hM4Di, a Gi DREADD, in the striatum. Mice recieved either 1 mg/kg CNO or vehicle to compare striatal astrocyte transcriptomes with and without Gi-GPCR signaling activation.