Cajal-Retzius Cells

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cell1140 wordssynced 2026-04-02

Cajal-Retzius Cells

<table class="infobox infobox-celltype">
<tr>
<th class="infobox-header" colspan="2">Cajal-Retzius Cells</th>
</tr>
<tr>
<td class="label">Allen Atlas ID</td>
<td><a href="https://portal.brain-map.org/atlases-and-data/rnaseq" target="_blank">CS202210140_3301</a></td>
</tr>
<tr>
<td class="label">Lineage</td>
<td>Neuron > Transient > Cajal-Retzius</td>
</tr>
<tr>
<td class="label">Markers</td>
<td>RELN, CALB1, LHX5, NRP1, ASTN1</td>
</tr>
<tr>
<td class="label">Brain Regions</td>
<td>Cortical marginal zone (Layer 1)</td>
</tr>
<tr>
<td class="label">Disease Vulnerability</td>
<td>Lissencephaly, Schizophrenia</td>
</tr>
</table>

Cajal-Retzius Cells

Introduction

Cajal Retzius Cells is an important component in the neurobiology of neurodegenerative diseases. This page provides detailed information about its structure, function, and role in disease processes.

Overview

Cajal-Retzius Cells are a critical transient population of neurons that play essential roles in cortical development. Named after Santiago Ramón y Cajal and Gustaf Retzius, who first described these cells in the late 19th century, they are among the first neurons generated in the developing cerebral cortex.

...

Cajal-Retzius Cells

Introduction

Cajal Retzius Cells is an important component in the neurobiology of neurodegenerative diseases. This page provides detailed information about its structure, function, and role in disease processes.

Overview

Cajal-Retzius Cells are classified within the Neuron > Transient > Cajal-Retzius lineage and are primarily located in the cortical marginal zone (Layer 1). These cells are transient - they are abundant during embryonic and early postnatal development but largely disappear in adulthood through programmed cell death.

Multi-Taxonomy Classification

Taxonomy Database Cross-References

| Taxonomy | ID | Name / Label |
|----------|----|---------------|
| Cell Ontology (CL) | [CL:0000695](https://www.ebi.ac.uk/ols4/ontologies/cl/classes/http%253A%252F%252Fpurl.obolibrary.org%252Fobo%252FCL_0000695) | Cajal-Retzius cell |

PanglaoDB Marker Cross-References

Unknown (PanglaoDB):

External Database Links

[Cell Ontology (CL:0000695)](https://www.ebi.ac.uk/ols4/ontologies/cl/classes/http%253A%252F%252Fpurl.obolibrary.org%252Fobo%252FCL_0000695)
[OBO Foundry (CL:0000695)](http://purl.obolibrary.org/obo/CL_0000695)
[Allen Brain Cell Atlas](https://portal.brain-map.org/atlases-and-data/bkp/abc-atlas)
[CellxGene Census](https://cellxgene.cziscience.com/)
[Human Cell Atlas](https://www.humancellatlas.org/)
[PanglaoDB](https://panglaodb.se/)

Taxonomy & Classification

| Database | ID | Name | Confidence |
|----------|----|------|------------|
| Cell Ontology | [CL:0000695](https://www.ebi.ac.uk/ols4/ontologies/cl/classes/http%253A%252F%252Fpurl.obolibrary.org%252Fobo%252FCL_0000695) | Cajal-Retzius cell | Exact |

PanglaoDB Marker Cross-References

Unknown (PanglaoDB):

External Database Links

[Cell Ontology (CL:0000695)](https://www.ebi.ac.uk/ols4/ontologies/cl/classes/http%253A%252F%252Fpurl.obolibrary.org%252Fobo%252FCL_0000695)
[OBO Foundry (CL:0000695)](http://purl.obolibrary.org/obo/CL_0000695)
[Allen Brain Cell Atlas](https://portal.brain-map.org/atlases-and-data/bkp/abc-atlas)
[CellxGene Census](https://cellxgene.cziscience.com/)
[PanglaoDB](https://panglaodb.se/)

Historical Discovery

Santiago Ramón y Cajal (1891)

Cajal first described these cells in 1891 as "células de casquete" (cap cells) based on their distinctive morphology with horizontally oriented axons in the marginal zone.

Gustaf Retzius (1894)

Retzius provided detailed anatomical descriptions, coining the term "Cajal-Retzius cells" that persists today.

Morphology and Cellular Properties

Morphological Features

Somatic Location: Horizontally oriented cell bodies in layer 1, just beneath the pial surface
Dendritic Arborization: Vertically oriented dendrites extending toward the pial surface
Axonal Projection: Horizontally running axons that travel long distances within layer 1, forming extensive axonal plexuses
Characteristic Axon Initial Segment: Thick, vertically oriented axon initial segment

Electrophysiological Properties

Cajal-Retzius cells exhibit unique firing properties:

Depolarized Resting Membrane Potential: ~-50 mV
High Input Resistance: 300-500 MΩ
Sodium-Dependent Action Potentials: Generate overshooting action potentials
Spontaneous Firing: Many fire spontaneously in the embryonic cortex
Depolarizing Responses: Typically respond to excitatory inputs with depolarization

Molecular Markers and Transcriptomic Profile

Primary Markers

RELN (Reelin): The defining secreted protein; crucial for cortical lamination
CALB1 (Calretinin): Calcium-binding protein
LHX5: Lim homeobox transcription factor
NRP1 (Neuropilin-1): Semaphorin receptor
ASTN1 (Astrin 1): Neuronal migration protein

Transcriptomic Signature

Single-cell RNA sequencing from the [Allen Cell Type Atlas](https://portal.brain-map.org/atlases-and-data/rnaseq) reveals:

High expression of Reelin signaling components
Distinct transcription factor profile (LHX5, FOXP2)
Extracellular matrix remodeling genes
Cell adhesion molecules

Developmental Functions

Cajal-Retzius cells serve critical functions during cortical development:

Cortical Lamination

The primary function of Cajal-Retzius cells is to secrete Reelin, which is essential for:

Neuronal Positioning: Guide postmitotic neurons to their correct laminar position

Pyramidal Cell Migration: Control radial migration of pyramidal neuron precursors

Inverted Cortical Architecture: Reelin deficiency leads to inverted cortical layers (lissencephaly)

Synaptogenesis

Provide scaffold for synaptic contacts
Express synaptic adhesion molecules
Guide thalamocortical axon targeting

Neuronal Survival

Secrete neurotrophic factors
Support adjacent neuron survival
Regulate programmed cell death

Normal Function in the Adult Brain

While Cajal-Retzius cells are predominantly transient, residual populations persist in the adult brain:

Layer 1 Interneurons

Small population remains in adult layer 1
Function as modulatory interneurons
May contribute to cortical processing

Role in Plasticity

Express activity-dependent genes
Potential role in adult plasticity
Contribute to Reelin signaling maintenance

Vulnerability in Disease

Lissencephaly

Causal Relationship: Loss of Cajal-Retzius cell function directly causes lissencephaly:

RELN Mutations: Loss of Reelin secretion

RELN Gene Deletions: Chromosomal abnormalities

DCX Mutations: Affect Cajal-Retzius cell migration

Pathological Features

Absent or reduced cortical gyration (smooth brain)
Thick, four-layered cortex
Neuronal migration defects
Severe intellectual disability

Schizophrenia

Evidence for Involvement

Postmortem studies show reduced Reelin expression in schizophrenia
Genetic associations with RELN polymorphisms
Altered Cajal-Retzius cell numbers in prefrontal cortex

Proposed Mechanisms

Reelin Deficiency: Reduced Reelin affects neuronal positioning

Synaptic Abnormalities: Impaired synapse formation

Network Dysconnectivity: Altered cortical circuitry

Other Neurological Conditions

Epilepsy: Altered Reelin signaling
Autism Spectrum Disorder: Reelin polymorphisms associated
Bipolar Disorder: Reelin expression changes

Reelin Signaling Pathway

The Reelin signaling cascade is essential for cortical lamination:

Reelin Secretion: Cajal-Retzius cells secrete Reelin into the extracellular matrix

Receptor Binding: Reelin binds to ApoER2 and VLDLR on target neurons

Dab1 Phosphorylation: Intracellular adaptor protein Dab1 is phosphorylated

Downstream Signaling: Activates PI3K/Akt and MAPK/ERK pathways

Cellular Effects: Controls cytoskeletal organization, migration, and synaptic plasticity

Reeler Mouse

The reeler mouse (RELN-deficient) provides a model system:

Inverted cortical layers
Cerebellar hypoplasia
Motor coordination deficits
Cognitive impairments

Therapeutic Implications

Drug Targets

Reelin agonists: Small molecules enhancing Reelin signaling
HDAC inhibitors: Increase RELN expression
ApoER2/VLDLR modulators: Enhance downstream signaling

Gene Therapy

RELN gene delivery
Cell replacement therapy
Exosome-mediated Reelin delivery

Research Applications

Reeler Mouse Model: Study cortical development
Organoid Systems: Model human cortical lamination
CRISPR Screens: Identify Reelin signaling components

Key Publications

[Cajal-Retzius cells: embryonic organizers of the cortex](https://doi.org/10.1038/s41583-020-0335-5). Nat Rev Neurosci, 2020.

[Reelin in cortical development and disease](https://doi.org/10.1016/j.neuropharm.2020.108214). Neuropharmacology, 2020.

[Molecular anatomy of the developing cerebral cortex](https://doi.org/10.1038/s41586-020-1972-0). Nature, 2020.

External Links

Allen Cell Type Atlas: [https://portal.brain-map.org/atlases-and-data/rnaseq](https://portal.brain-map.org/atlases-and-data/rnaseq)
Allen Human Brain Atlas: [https://human.brain-map.org/](https://human.brain-map.org/)
Reeler Mouse: [Jackson Laboratory](https://www.jax.org/strain:000235)
[Cell Types Index](/cell-types) RELN Gene
Reelin Signaling Pathway
Cortical Development
[Lissencephaly](/diseases/lissencephaly)
S- [Genes Index](/genes)Genes In- [Mechanisms Index](/mechanisms)- Mechanisms Index
--

Background

The study of Cajal Retzius Cells has evolved significantly over the past decades. Research in this area has revealed important insights into the underlying mechanisms of neurodegeneration and continues to drive therapeutic development.

Historical context and key discoveries in this field have shaped our current understanding and will continue to guide future research directions.

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