Reversible CD8 T cell-neuron cross-talk causes aging-dependent neuronal regenerative decline

Area of Science:

• Neuroscience
• Immunology
• Regenerative Medicine

Background:

• Aging is linked to poor axonal regeneration and disability after nerve injuries.
• The mechanisms behind age-related regenerative decline are not fully understood.

Purpose of the Study:

• To investigate the role of T cell signaling in age-dependent decline of axonal regeneration.
• To identify therapeutic targets for enhancing nerve repair in aging individuals.

Main Methods:

• RNA sequencing of mouse sciatic dorsal root ganglia (DRG) before and after sciatic nerve injury (SNI).
• Analysis of T cell signaling pathways, including lymphotoxin, NF-κB, and CXCL13.
• Investigating the recruitment of CXCR5+CD8+ T cells and their effect on axonal regeneration.
• Evaluating the impact of CXCL13 neutralization on neurological recovery.

Main Results:

• Aging mice showed increased T cell signaling in DRG, with elevated CXCL13 expression by neurons.
• CXCL13 attracted CXCR5+CD8+ T cells to injured neurons, which repressed axonal regeneration via caspase 3 activation.
• Neutralizing CXCL13 blocked T cell recruitment and improved nerve regeneration, reversing age-related deficits.

Conclusions:

• Aging-associated axonal injury and poor regeneration involve T cell-neuron cross-talk.
• Targeting the CXCL13 pathway can enhance axonal regeneration and neurological recovery after nerve injury in aging individuals.