Monitoring regional astrocyte diversity by cell-type specific proteomic labelingin vivo

Abstract

Astrocytes exhibit regional heterogeneity in morphology, function and molecular composition to support and modulate neuronal function and signaling in a region-specific manner. To characterize regional heterogeneity of astrocytic proteomes of different brain regions we established an Aldh1l1-MetRSL274G mouse line that allows cell-type specific labeling of newly synthesized proteins in vivo and analyzed astrocytic proteins from four different brain regions by mass spectrometry. Identified proteins are specific for astrocytes and show a high overlap with proteins compiled in AstroProt, a newly established database for astrocytic proteins. Gene enrichment analysis reveals high overlap among brain regions, and only subtle changes in abundances of key astrocytic proteins for hippocampus, cortex and striatum. However, the cerebellar proteome stands out with proteins being associated with calcium signaling or bipolar disorder. Subregional differences of translation dynamics in single hippocampal astrocytes indicates distinct subregional heterogeneity and highlights the applicability of our toolbox to study dynamic astrocytic proteomes in vivo.

Advances in proteomic phenotyping of microglia in neurodegeneration

“…Because the BONCAT method only labels newly synthesized proteins, there may be challenges with achieving a desired depth of proteome, however, this feature may be an asset for studying event-related or stimuli-related changes to the proteome. Recently, BONCAT has been successfully applied to astrocytes as well [163]. The extension of the BONCAT method to label and profile microglia, other brain immune cells and glial subtypes has not been reported thus far.…”