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:MERFISH data from two young and two old WT C57BL/6J mouse livers, using a custom 500-gene panel targeted at aging and cancer-associated genes.
Project description:Microglia adopt various spatially resolved gene and functional profiles in amyloidosis mice, for example the relative enrichment of DAMs proximal to plaques. To spatially resolve these transcriptional changes and identify microglial populations responsive to TREM2 small molecule agonism, multiplexed error-robust fluorescence in situ hybridization (MERFISH) was conducted on sagittal brain sections from VG-3909–treated 5xFAD;hTREM2 mice, 12 hours post-oral dosing. Simultaneous immunostaining using an anti-amyloid antibody enabled spatial correlation of microglial transcriptomes with amyloid plaque localization. The custom MERFISH panel comprised 500 genes, included cell-type markers and microglia-focused genes.
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.