Response of Astrocyte Subpopulations Following Spinal Cord Injury

Cells, 2022 · DOI: 10.3390/cells11040721 · Published: February 18, 2022

Simple Explanation

This study investigates how different types of astrocytes, which are support cells in the spinal cord, respond to spinal cord injury (SCI). The researchers focused on whether SCI causes changes in the distribution of these astrocyte types, particularly one type known for promoting synapse formation. The study also examined whether SCI changes the expression of genes related to synapse formation within these different astrocyte populations. They used flow cytometry and RNAscope to analyze astrocyte populations. The researchers compared spinal cord tissue from mice with SCI to that of uninjured mice. They also confirmed that these astrocyte subpopulations are present in the human spinal cord, suggesting a potential conservation across species.

Study Duration

6 weeks

Participants

Male and female adult mice between 3 and 9 months of age

Evidence Level

Not specified

Key Findings

1
Astrocyte subpopulation distribution in the spinal cord did not change to a selectively synaptogenic phenotype following mouse cervical hemisection-type SCI.
2
Spinal cord astrocytes expressed synapse formation-associated genes to a similar degree across subpopulations, as well as in an unchanged manner between uninjured and SCI conditions.
3
Astrocyte subpopulations are also present in the human spinal cord in a similar distribution as mouse, suggesting possible conservation of spinal cord astrocyte heterogeneity across species.

Research Summary

This study examined the response of astrocyte subpopulations to spinal cord injury (SCI) in mice. The researchers investigated whether SCI induces changes in astrocyte subpopulation distribution and expression of synapse formation-associated genes. The findings showed that SCI did not cause a significant shift toward a synaptogenic astrocyte phenotype or alter the expression of synapse-related genes within specific astrocyte subpopulations. The proportion of the synaptogenic Population C remained low. The study also confirmed that similar astrocyte subpopulations exist in the human spinal cord, suggesting evolutionary conservation. These findings contribute to understanding astrocyte heterogeneity and its role in SCI.

Practical Implications

Understanding Astrocyte Roles

The study sheds light on the complex roles of astrocytes in the context of spinal cord injury, indicating that simply shifting astrocyte populations may not be a sufficient strategy to promote synapse formation and recovery.

Therapeutic Strategies

The development of novel approaches to shift the distribution of the endogenous astrocyte makeup selectively toward a particular subpopulation (s) and/or the exogenous delivery of a particular subpopulation represent potentially promising therapeutic strategies.

Conserved Heterogeneity

The conservation of astrocyte subpopulations in human spinal cord suggests the potential for translating findings from animal models to human therapies, although further research is needed to confirm functional similarities.

Study Limitations

1
The study only analyzed a long-term time point, it is possible that during the earlier phases after SCI there are signiﬁcant alterations in astrocyte subpopulation distribution and/or in the expression of genes such that those involved in regulating synapse formation.
2
There is a possibility that astrocytes characterized into subpopulations by other classiﬁcation schemes might yield different results, such that, for example, distinct populations may differentially increase or decrease expression of synapse-associated genes after damage.
3
Although we identified astrocytes of the same subpopulations in human spinal cord tissues based on histological analysis of differential expression of a cell surface marker panel, it still remains unclear whether these human spinal cord astrocytes possess the same functional characteristics

Your Feedback

Was this summary helpful?

Back to Spinal Cord Injury