Link Protein 1 Is Involved in the Activity-Dependent Modulation of Perineuronal Nets in the Spinal Cord

Area of Science:

• Neuroscience
• Neuroplasticity
• Spinal Cord Injury Research

Background:

• Mature nervous systems balance network stability with experience-dependent plasticity.
• Perineuronal nets (PNNs) regulate this plasticity-stability balance, essential for proper nervous system function.
• Reduced spinal PNNs correlate with maladaptive plasticity post-spinal cord injury (SCI), an effect mitigated by activity-dependent therapies.

Purpose of the Study:

• To investigate the role of cartilage link protein 1 (Crtl1) in activity-dependent modulation of spinal PNNs surrounding motoneurons.
• To assess the impact of Crtl1 on maladaptive plasticity following SCI.

Main Methods:

• Voluntary wheel-running protocol to study activity-dependent PNN modulation in wild-type (WT) and Crtl1 knockout (Crtl1 KO) mice.
• Thoracic spinal cord injury (SCI) induction in WT and Crtl1 KO mice.
• Evaluation of functional outcomes, including hyperreflexia and hyperalgesia, for 35 days post-SCI.

Main Results:

• Voluntary wheel running increased spinal PNNs in WT mice but not in Crtl1 KO mice, indicating Crtl1 mediates activity-dependent PNN modulation.
• Crtl1 KO mice exhibited aberrant spinal PNNs and increased spinal plasticity at baseline.
• Hyperreflexia and hyperalgesia were present in Crtl1 KO mice before SCI and did not worsen post-injury, unlike in WT-injured mice.

Conclusions:

• Cartilage link protein 1 plays a crucial dual role in both the formation and activity-dependent modulation of spinal PNNs.
• Crtl1 is essential for the proper function of PNNs in spinal circuits, particularly in regulating plasticity after SCI.
• Targeting Crtl1 may offer therapeutic strategies for managing maladaptive plasticity and improving outcomes after spinal cord injury.