Neural Cell Identity Markers
What are Neural Cell Markers?
Neurons and glia in neural tissue or cultures are commonly visualized and identified by immunodetection of cell-specific antigenic markers, including transcription factors, enzymes, cytoskeletal proteins, cell surface proteins, and secreted factors. Neural Cell Markers are the key to understanding the diverse world of neurons and glia. Bio-Techne offers a wide range of primary antibodies for precise identification, ELISA Kits for molecule detection, and exclusive tools including bioactive small molecules, caged compounds, and fluorescent probes, for functional exploration.
Neural cell markers allow researchers to:
- Determine neural cell type
- Distinguish neurons from other brain cells (e.g., neurons vs glial)
- Determine neuronal identity (e.g., subtypes)
- Define a neuron’s function (e.g., excitatory vs inhibitory)
- Establish synaptic partners (e.g., pre- and post-synaptic)
Neurons are electrically excitable cells that transmit signals (electrical and chemical) supporting a wide range of functions including cognition, sensory perception and movement. Morphologically, neurons contain four well defined structural compartments including dendrites, soma, axon and synaptic terminal. Morphology and connectivity have traditionally been instrumental in neuronal identification, but detection of molecular markers is key to establishing neuronal identity.
Commonly Used Neuronal Markers
| Immature Neuron Markers | Mature Neuron Markers | Functional Neuron Markers | Synaptic Markers |
|---|---|---|---|
| Doublecortin, NCAM, NeuroD1 | Enolase 2/NSE, NeuN, MAP2*, βIII Tubulin, Neurofilament Light, Neurofilament Medium, Neurofilament Heavy, GAP-43 | ChAT, Tyrosine Hydroxylase, GAD65/GAD67, VGLUT1, VGLUT2, Pet1, SERT | Synaptophysin, Bassoon, PSD-95 |
*In comparison with β-III Tubulin, MAP2 labels more mature neurons.
NCAM: Immature Neuron Marker
(NCAM-1)/CD56 was detected in SH-SY5Y cells with Goat Anti-Human/Mouse NCAM-1/CD56 Polyclonal Antibody (AF2408)(red). Cells were stained with NorthernLights 557-conjugated Donkey Anti-Goat IgG Secondary Antibody (NL001). Phalloidin (green) stained Actin filaments and DAPI (blue) stained the cell nuclei. NCAM-1/CD56 expression was localized to the plasma membrane
GAP-43: Mature Neuron Marker
GAP-43 was detected in a mature retinal ganglion cell with Sheep Polyclonal GAP-43 antibody [NBP1-41123]. Staining shows axon outgrowth.
Functional Neuron Markers: Tyrosine Hydroxylase
Tyrosine Hydroxylase was detected in immersion fixed paraffin-embedded sections of human brain (medulla) using Mouse Anti-Human/Mouse Tyrosine Hydroxylase Monoclonal Antibody (Catalog # MAB7566) at 25 µg/mL overnight at 4 °C. Tissue was stained using the Anti-Mouse HRP-DAB Cell & Tissue Staining Kit (brown; Catalog # CTS002) and counterstained with Hematoxylin (blue; Catalog # 5222). Specific staining was localized to neurons.
Synaptophysin: Synaptic Marker
Synaptophysin was detected in perfusion fixed frozen sections of mouse brain hippocampus with Mouse Anti-Human Synaptophysin Monoclonal Antibody (MAB5555) used at 15 µg/mL (red). Tissue was stained using the NorthernLights™ 557-conjugated Anti-Mouse IgG Secondary Antibody (NL007). Nuclei were counterstained with DAPI (blue). Synaptophysin staining is present in cytoplasm and nuclei.
Neuronal Subtype Markers
Identifying a neuron's subtype is key to understanding its function within a specific network. Single-cell RNA sequencing approaches have facilitated the identification of new subtype specific molecular markers. Learn about molecular markers to facilitate the study of serotonergic neurons, retinal ganglion cells, and sensory (mechanosensitive and nociceptive) neurons.
Serotonergic Neurons1
| Serotonergic Neurons (R2 5-HT sub-lineage) | Neuronal Subtype Specific Properties | |
|---|---|---|
| R2-1 subtype | Vglut3 low/Thp2/GLI2 high OXTR+ Unresponsive to senktide |
R2 5-HT neurons arise from rhombomere 2 in the embryonic hindbrain and localize to the median raphe |
| R2-2 subtype | Vglut3 high/Thp2/GLI2 low Tacr3+ Unresponsive to oxytocin |
The R2 5-HT sub-lineage is now known to consist of two main subtypes and participates in sensorimotor gating. |
Sensory Neurons2
| Sensory Neuron | Neuronal Subtype Specific Properties | |
|---|---|---|
| NF1 class | NECAB2 |
|
| NF2 class | CALB1 |
|
| NF3 class | FAM19A1 |
|
Retinal Ganglion Cells3
| Retinal Ganglion Cells (RGCs) |
Neuronal Subtype Specific Properties | |
|---|---|---|
| Subtype 34 | Zic1+ high |
|
| Subtype 27 | Runx1+ high |
|
| Subtype 3 | Follistatin+ high |
|
Non-Neuronal Cells
Glial cells are non-neuronal cells found in the central and peripheral nervous system including microglia and macroglia cells. Among these, macroglia cells include astrocytes, oligodendrocytes, ependymal cells, radial glia, Schwann cells and satellite cells. Glial cells function to support a variety of neuronal activities including migration, axonal outgrowth and synaptic activity. Additionally, glial cells provide neurons with trophic and metabolic support and help maintain synaptic homeostasis.
Astrocytes
Astrocytes are the most ubiquitous and diverse of the glial cells, being both functionally and molecularly diverse. Functionally, astrocytes play a role in neurotransmitter clearance, ion homeostasis and in the regulation of synapse number, thereby modulating neuronal activity through different mechanisms. Their molecular diversity is exemplified by the variable expression of key proteins. Three types of astrocyte have been identified, based on expression of transcription factors and cell surface markers, but a greater diversity may exist.
This fluorescent ICC image demonstrates detection of GFAP in immersion-fixed rat astrocytes using 10 µg/mL Sheep Anti-Human GFAP Antigen Affinity-purified Polyclonal Antibody (AF2594) for 3 hours at room temperature (red). Cells were stained with the NorthernLights™ 557-conjugated Anti-Sheep IgG Secondary Antibody (NL010) and counterstained with DAPI (blue).
Oligodendrocytes
Oligodendrocytes provide metabolic support and myelinate neuronal axons in the CNS. Insulating-myelin sheaths are indispensable for fast action potential conduction along the neuronal axon. Oligodendrocytes may be molecularly identified by the expression of various markers including:
This immunohistochemistry image shows detection of MBP in mouse brain slices with Myelin Basic Protein Monoclonal Antibody (2H9) [NBP2-22121]. Mouse brain cryosections were stained with MBP antibody at a dilution of 1:400 and secondary antibody anti-mouse Alexa Fluor 555 IgG. Nuclei were counterstained with DAPI (blue).
Microglia
Microglia are the immune cells of the nervous system. They are macrophages that serve as the first line of immune defence in the CNS, targeting damaged neurons, plaques and infectious agents for phagocytosis. Even in the absence of a trigger or insult to the brain, microglia constantly monitor their surrounding tissues and participate in the maintenance of homeostasis. During development, microglia-derived factors influence neuronal survival, either supporting survival or inducing cell death via apoptosis. Identification of microglia has generally used markers such as CD45 expression, although more recently Cx3cr1 and Tmem119 have been identified as microglia specific markers.
Orthogonal Validation Strategies. Immunohistochemistry-Paraffin demonstrating TMEM119 Antibody (CL8714) [NBP2-76985] staining in human cerebral cortex and liver tissues. Corresponding TMEM119 RNA-seq data are presented for the same tissues. Staining of human cerebral cortex shows moderate to strong membranous positivity in microglia. Staining of human liver shows no positivity in hepatocytes as expected.
Activation of Microglia
Following an insult to the brain, for example by infectious pathogens crossing the blood-brain barrier, microglia transform from a ramified to an amoeboid morphology, which correspond with their inactive and active states, respectively. Upon activation, microglia undergo changes in gene expression that underscore their new functionalities, for example the ability to produce inflammatory substances and phagocytose.
Genes Modulated by LPS-induced Microglia Activation
| Upregulated Genes | LCN2, CCL3, CXCL10, CCL5, IL-1b, TLRr2 |
| Downregulated Genes | TMEM119, OLFM-L3, LTC4S, ADORA3, P2RY12 |
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Okaty, BW et al. (2015) Multi-scale molecular deconstruction of the serotonin neuron system. Neuron 88:774. PMID: 26549332.
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Usoskin, D et al. (2015) Unbiased classification of sensory neuron types by large-scale single-cell RNA sequencing. Nat Neurosci 18:145. PMID: 25420068.
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Rheaume, BA et al. (2018) Single cell transcriptome profiling of retinal ganglion cells identifies cellular subtypes. Nat Commun 9:2759. PMID: 30018341.