Monitoring regional astrocyte diversity by cell type‐specific proteomic labeling in vivo. Issue 3 (19th November 2022)

• Record Type: Journal Article
• Authors: Prabhakar, Priyadharshini; Pielot, Rainer; Landgraf, Peter; Wissing, Josef; Bayrhammer, Anne; van Ham, Marco; Gundelfinger, Eckart D.; Jänsch, Lothar; Dieterich, Daniela C.; Müller, Anke
• Is Part Of: Glia. Volume 71:Issue 3(2023)
• Page Start: 682
• Page End: 703
• Publication Date: 2022-11-19
• Subjects: astrocytic proteome -- AstroProt -- cell type‐specific -- heterogeneity -- metabolic labeling -- MetRSL274G; Neuroglia -- Periodicals; Neurology -- Periodicals; 611.0188
• DOI: 10.1002/glia.24304
• Languages: English
• ISSNs: 0894-1491

Abstract

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 inducible Aldh1l1‐methionyl‐tRNA‐synthetase L274G (MetRS L274G ) mouse line that allows astrocyte‐specific metabolic labeling of newly synthesized proteins by azidonorleucine (ANL) in vivo and subsequent isolation of tagged proteins by click chemistry. We analyzed astrocytic proteins from four different brain regions by mass spectrometry. The induced expression of MetRS L274G is restricted to astrocytes and identified proteins show a high overlap with proteins compiled in "AstroProt, " a newly established database for astrocytic proteins. Gene enrichment analysis reveals a high similarity among brain regions with subtle differences in enriched biological processes and in abundances of key astrocytic proteins for hippocampus, cortex and striatum. However, the cerebellar proteome stands out with proteins being highly associated with the calcium signaling pathway or with bipolar disorder. Subregional analysis of single astrocyte TAMRA intensities in hippocampal layers indicates distinct subregional heterogeneity of astrocytes and highlights the applicability of our toolbox to study differences of astrocytic proteomes in vivo. Main Points: In vivo metabolic labeling enables astrocyte‐specific proteome analysis in four brain regions by LC–MS/MS. Biological processes or key astrocytic proteins show subtle variances between brain regions and region‐specific disease associations.