Astrocyte Development and Heterogeneity

Cold Spring Harb Perspect Biol, 2015 · DOI: 10.1101/cshperspect.a020362 · Published: January 1, 2015

Simple Explanation

Astrocytes, once thought to be homogeneous, are now recognized as a diverse population with regional differences in the brain. This heterogeneity could explain how the CNS retains embryonic positional information into adulthood. Neural stem cells (NSCs) in the V-SVZ region of the brain retain regional properties, generating specific subtypes of interneurons. This positional identity is determined by transcription factors expressed early in development and maintained postnatally. Astrocytes in the spinal cord are allocated regionally according to a segmental template, influencing the development and maintenance of the sensorimotor circuit. Ventral astrocytes, for example, play a role in motor neuron axon orientation and synaptogenesis.

Study Duration

Not specified

Participants

Not specified

Evidence Level

Review

Key Findings

1
Adult V-SVZ astrocytes are regionally specified NSCs, with different regions generating specific subtypes of olfactory bulb interneurons, indicating a mosaic organization.
2
Astrocytes in the spinal cord are regionally allocated according to a segmental template, with limited migration from their domains of origin.
3
Ventral astrocytes in the spinal cord play crucial roles in the maintenance of motor neuron axon orientation, synaptogenesis, and alpha-motor neuron survival, mediated by Sema3a.

Research Summary

Astrocytes, the most abundant cell types in the mammalian brain, are now recognized as a functionally diverse population, challenging the notion of homogeneity. Regional and temporal factors contribute to the heterogeneity of both neural stem cells (NSCs) and astrocytes, influencing the development of diverse neuronal and glial subpopulations. The regional investment of astrocytes in the CNS suggests the existence of “astromeres,” regionally specialized astrocytes tailored for the support of local neuronal subtypes and neural circuit formation and function.

Practical Implications

Understanding Brain Organization

Astrocytes' diversity will provide fundamental clues to understand regional brain organization and function.

Therapeutic Targets

A better understanding of astrocyte heterogeneity may provide insights for treating neurological disorders.

Neural Circuit Formation

Regional astrocyte functions are important for neuronal circuit formation and maintenance.

Study Limitations

1
Limited literature on heterogeneity of astrocytes.
2
Functional correlates of morphological and molecular subtypes have not been clearly shown.
3
Difficulty in manipulating astrocyte function in a cell-type and region-specific manner.

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