Neural Circuit-Specialized Astrocytes: Transcriptomic, Proteomic, Morphological, and Functional Evidence

Astrocytes are ubiquitous in the brain and are widely held to be largely identical. However, this view has not been fully tested, and the possibility that astrocytes are neural circuit specialized remains largely unexplored. Here, we used multiple integrated approaches, including RNA sequencing (RNA-seq), mass spectrometry, electrophysiology, immunohistochemistry, serial block-face-scanning electron microscopy, morphological reconstructions, pharmacogenetics, and diffusible dye, calcium, and glutamate imaging, to directly compare adult striatal and hippocampal astrocytes under identical conditions. We found significant differences in electrophysiological properties, Ca2+ signaling, morphology, and astrocyte-synapse proximity between striatal and hippocampal astrocytes. Unbiased evaluation of actively translated RNA and proteomic data confirmed significant astrocyte diversity between hippocampal and striatal circuits. We thus report core astrocyte properties, reveal evidence for specialized astrocytes within neural circuits, and provide new, integrated database resources and approaches to explore astrocyte diversity and function throughout the adult brain. [Display omitted] •Multiple approaches were used to assess astrocyte diversity in two neural circuits•Physiological and anatomical studies showed evidence for astrocyte functional diversity•RNA-seq, proteomic, and cell marker analyses confirmed diversity•Evidence is provided for brain neural-circuit-specialized astrocytes The Khakh lab used state-of-the-art optical, anatomical, electrophysiological, transcriptomic, and proteomic approaches to explore astrocyte similarities and differences in two neural circuits. Candid evaluation of the data across ten approaches provided not only strong evidence for astrocyte diversity but also an experimental workflow to explore astrocyte diversity across the brain.