Table 1.
Markers of astrocytes
| Molecule/Antigen | Detection Agent/Technique | Properties and Functional Relevance | Reference Nos. |
|---|---|---|---|
| Glial fibrillary acidic protein, GFAP | Monoclonal and polyclonal antibodies | Intermediate filament protein, expressed in many cells outside the nervous system; in the CNS expressed in a subpopulation of astrocytes with substantial region variability. Generally, GFAP expression is upregulated in reactive astroglia. | 477, 715, 1355, 1880 |
| Vimentin | Monoclonal and polyclonal antibodies | Intermediate filament protein; expressed in immature astrocytes, in subpopulations of protoplasmic and fibrous astrocytes, in Bergmann glia, and in tanycytes. Vimentin expression is upregulated in reactive astrocytes. | 394, 597, 1350, 1351, 1568 |
| S100B protein | Monoclonal antibodies | Ca2+-binding proteins, which act as Ca2+ buffers as well as Ca2+ sensors. Antibodies against S100B stain more astrocytes than GFAP in the grey as well as in the white matter. | 444, 1251, 1549 |
| Glutamate transporters: EAAT-1 (GLAST), EAAT-2 (GLT-1) | Monoclonal antibodies | Astroglia-specific glutamate transporters; show regional variability: EAAT1 is predominantly expresed in cerebellum; in other regfions EAAT2 is the main transporter type. | 110, 807, 1570, 1606, 1882 |
| Glutamine synthetase | Monoclonal and polyclonal antibodies | Astroglia-specific enzyme converting ammonia and glutamate into glutamine. Expressed in the majority of astrocytes. Immunostaining reveals full structure of the cell due to cytosolic localization of the enzyme. | 49, 417, 1237, 1920 |
| Aldehyde dehydrogenase 1 family, member L1 (ALDH1L1) | ALDH1L11-specific polyclonal antibody | ALDH1L1 is a key enzyme in folate metabolism contributing to nucleotide biosynthesis and cell division. Proposed as a specific astroglial markers with a reach substantially broader than GFAP. ALDH1L1 expression however changes with age, and it was also detected in a subpopulation of oligodendrocytes. | 275, 1916 |
| Connexins: Cx43, Cx30 | Monoclonal and polyclonal antibodies | Both Cx43 and Cx30 are expressed exclusively in astrocytes; the Cx30 is expressed mostly in grey matter (being particularly concentrated in astroglial endfeet) and is absent in astrocytes from white matter. | 413, 1189 |
| Aquaporin: AQP4 | Monoclonal antibodies | AQP4 in the CNS is expressed exclusively in astrocytes and ependymocytes. In healthy astrocytes, AQP4 is preferentially located in the endfeet and hence stains this structure. | 1184 |
| Transcriptional factor SOX9 | Polyclonal antibodies | Specifically labels nuclei of astrocytes outside the neurogenic niches. | 1701 |