Developmental downregulation of LIS1 expression limits axonal extension and allows axon pruning

Area of Science:

• Neuroscience
• Molecular Biology
• Regenerative Medicine

Background:

• Neuronal regenerative capacity declines significantly with age.
• Intrinsic molecular mechanisms underlying age-dependent regeneration loss are poorly understood.
• Axonal growth downregulation impacts functional recovery after nerve injury.

Purpose of the Study:

• To identify intrinsic molecular factors responsible for reduced axonal extension in aging neurons.
• To investigate the role of LIS1 in age-related decline of neuronal regeneration.
• To explore therapeutic strategies for enhancing nerve repair in mature neurons.

Main Methods:

• Studied dorsal root ganglion (DRG) neurons from mature and young animals.
• Manipulated LIS1 expression using exogenous delivery and calpain inhibition.
• Investigated the interaction between LIS1, CTCF, and GSK-3β.
• Assessed sciatic nerve regeneration in vivo.

Main Results:

• Developmental downregulation of LIS1 causes decreased axonal extension in mature DRG neurons.
• Exogenous LIS1 or calpain inhibition restored axonal extension and promoted sciatic nerve regeneration.
• CTCF suppresses LIS1, leading to GSK-3β accumulation and axonal extension failure.
• Sustained LIS1 inhibited developmental axon pruning.

Conclusions:

• LIS1 downregulation is a key intrinsic factor limiting axonal regeneration in aging neurons.
• LIS1 augmentation offers a potential therapeutic strategy for nerve repair.
• LIS1 regulation balances axonal growth and pruning during neural circuit maturation.