Visualizing the brain's astrocytes

Methods Enzymol. 2019;622:129-151. doi: 10.1016/bs.mie.2019.02.006. Epub 2019 Mar 4.

Abstract

Astrocytes are the most abundant cell type in the brain and are a crucial part of solving its mysteries. Originally assumed to be passive supporting cells, astrocyte's functions are now recognized to include active modulation and information processing at the neural synapse. The full extent of the astrocyte contribution to neural processing remains unknown. This is, in part, due to the lack of methods available for astrocyte identification and analysis. Existing strategies employ genetic tools like the astrocyte specific promoters glial fibrillary acidic protein (GFAP) or Aldh1L1 to create transgenic animals with fluorescently labeled astrocytes. Recently, small molecule targeting moieties have enabled the delivery of bright fluorescent dyes to astrocytes. Here, we review methods for targeting astrocytes, with a focus on a recently developed methylpyridinium targeting moiety's development, chemical synthesis, and elaboration to provide new features like light-based spatiotemporal control of cell labeling.

Keywords: Astrocytes; Brain imaging; Cationic fluorophore; Euroimaging; Glia imaging; Photoactivatable; Small molecules.

MeSH terms

  • Animals
  • Astrocytes / cytology*
  • Astrocytes / ultrastructure
  • Brain / cytology*
  • Brain / ultrastructure
  • Fluorescent Dyes / analysis
  • Glial Fibrillary Acidic Protein / analysis
  • Glial Fibrillary Acidic Protein / genetics
  • Humans
  • Neuroimaging / methods*
  • Oxidoreductases Acting on CH-NH Group Donors / analysis
  • Oxidoreductases Acting on CH-NH Group Donors / genetics
  • Promoter Regions, Genetic
  • Pyridinium Compounds / analysis
  • Staining and Labeling / methods*
  • Zebrafish

Substances

  • Fluorescent Dyes
  • Glial Fibrillary Acidic Protein
  • Pyridinium Compounds
  • Oxidoreductases Acting on CH-NH Group Donors
  • formyltetrahydrofolate dehydrogenase