Abundant Expression of Guidance and Synaptogenic Molecules in the Injured Spinal Cord

PLoS ONE, 2014 · DOI: 10.1371/journal.pone.0088449 · Published: February 11, 2014

Spinal Cord Injury Regenerative Medicine Neurology

Simple Explanation

Following spinal cord injury, new axonal connections can form, particularly in the corticospinal tract (CST). These connections can create detour circuits around the injury site, potentially aiding in functional recovery. The formation and stabilization of these new synaptic contacts are not fully understood. This study explores the expression of guidance and synaptogenic molecules in the cervical spinal cord of healthy and spinal cord-injured mice. The researchers focused on specific interneuron populations: C3–C4 short propriospinal neurons (SPSN), C3–C5 long propriospinal neurons (LPSN), and glycinergic neurons, examining the presence of molecules like slits, semaphorins, synCAMs, neuroligins, and ephrins.

Study Duration

Not specified

Participants

Adult mice between 6 and 12 weeks of age

Evidence Level

Not specified

Key Findings

1
Most of the guidance and synaptogenic molecules studied are present not only in the developing CNS but also in the adult CNS.
2
Some molecules, such as slits, Sema7a, SynCAM4, and NL1, are preferentially expressed in propriospinal neurons compared to glycinergic neurons.
3
The expression pattern of these molecules appears stable over time and is largely unaffected by a thoracic hemisection.

Research Summary

This study investigates the expression of guidance and synaptogenic molecules in the cervical spinal cord of mice, both healthy and with spinal cord injuries, focusing on interneuron populations. The findings reveal that many of these molecules, crucial for neuronal circuit formation during development, are also present in the adult CNS, suggesting their involvement in axonal connection remodeling after injury. While most molecules showed uniform expression, some were preferentially expressed in propriospinal neurons. The overall expression pattern remained stable over time, even after spinal cord injury.

Practical Implications

Understanding Molecular Cues

The identification of specific guidance and synaptogenic molecules present in the adult spinal cord provides potential targets for therapeutic interventions.

Targeted Therapies

The preferential expression of certain molecules in propriospinal neurons suggests opportunities for developing targeted therapies to promote detour circuit formation.

Future Research

Further studies are needed to define the precise roles of these molecules in circuit formation and maturation after injury, potentially leading to new therapeutic approaches.

Study Limitations

1
The study primarily focuses on membrane-bound molecules in the cervical spinal cord remote from the lesion site.
2
The study acknowledges that gene expression changes are magnified at the lesion site and that the effects remote from the lesion site might be more moderate.
3
The study can only show that mRNAs are expressed in the neuronal cell body and assumes that functional receptors are present on growing CST axons.

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