GEARBOCS: An Adeno Associated Virus Tool forIn VivoGene Editing in Astrocytes

Abstract

AbstractIn the mammalian central nervous system (CNS), astrocytes are indispensable for brain development, function, and health. However, non-invasive tools to study astrocyte biology and functionin vivohave been limited to genetically modified mice. CRISPR/Cas9-based genome engineering enables rapid and precise gene manipulations in the CNS. Here, we developed a non-invasive astrocyte-specific method utilizing a single AAV vector, GEARBOCS (Gene Editing in AstRocytes Based On CRISPR/Cas9 System). We verified GEARBOCS’ specificity to mouse cortical astrocytes and demonstrated its utility for three types of gene manipulations: knockout (KO); tagging (TagIN); and reporter gene knock-in (Gene-TRAP) strategies. We deployed GEARBOCS to determine whether cortical astrocytes express Vamp2 protein. The presence of Vamp2-positive vesicles in cultured astrocytes is well-established, however, Vamp2 protein expression in astrocytesin vivohas proven difficult to ascertain due to its overwhelming abundance in neurons. Using GEARBOCS, we delineated thein vivoastrocytic Vamp2 expression and found that it is required for maintaining excitatory and inhibitory synapse numbers in the visual cortex. GEARBOCS strategy provides fast and efficient means to study astrocyte biologyin vivo.Graphical Abstract (Main Points)•GEARBOCS is a single AAV-based CRISPR tool to target mouse astrocytesin vivo.•GEARBOCS can be used to knockout, tag, or gene-trap genes of interest in astrocytesin vivo.•Using GEARBOCS, we confirmed astrocytes express Vamp2 and found that astrocytic Vamp2 is required for maintenance of excitatory and inhibitory synapse numbersin vivo.