Spinal cord regeneration in Xenopus tadpoles proceeds through activation of Sox2-positive cells

Neural Development, 2012 · DOI: 10.1186/1749-8104-7-13 · Published: April 26, 2012

Simple Explanation

Amphibians like Xenopus tadpoles can regenerate their spinal cord after injury, unlike mammals. This study investigates the role of Sox2-positive cells in this regeneration process. The research found that tail amputation in tadpoles leads to an increase in Sox2 levels and proliferation of Sox2+ cells in the spinal cord. Blocking Sox2 function impairs tail regeneration, suggesting its importance. After spinal cord injury, Sox2+ cells migrate to the injury site to help rebuild the spinal cord. Sox2 levels also correlate with the tadpoles' ability to regenerate during different developmental stages.

Study Duration

Not specified

Participants

Xenopus laevis tadpoles at various stages

Evidence Level

Not specified

Key Findings

1
Tail amputation increases Sox2 mRNA and protein levels in the spinal cord, lateral line, and olfactory epithelium, indicating a systemic response to tissue injury.
2
Tail amputation activates proliferation of Sox2+ cells in the spinal cord, with BrdU incorporation studies showing increased cell division in Sox2-positive cells.
3
Overexpression of a dominant-negative form of Sox2 impairs tail regeneration and reduces BrdU incorporation in spinal cord and notochord cells.

Research Summary

This study investigates the role of Sox2+ cells in spinal cord regeneration in Xenopus laevis tadpoles after tail amputation and spinal cord transection. The results demonstrate that spinal cord injury leads to increased levels of Sox2 and proliferation of Sox2+ cells, which contribute to the regeneration process. The study supports a model in which spinal cord damage activates proliferation and/or migration of Sox2+ cells, allowing regeneration of the spinal cord or reconstitution of the ependymal epithelium.

Practical Implications

Understanding Spinal Cord Regeneration

The study provides insights into the cellular and molecular mechanisms involved in spinal cord regeneration in amphibians, which could potentially inform strategies for promoting regeneration in mammals.

Therapeutic Targets

Sox2+ cells and the pathways regulating their activity could be potential therapeutic targets for promoting spinal cord repair after injury.

Loss of Regenerative Capacity

Understanding why regenerative capacity is lost during metamorphosis in Xenopus tadpoles could reveal factors that inhibit regeneration in mammals.

Study Limitations

1
The dominant-negative Sox2 construct used could interfere with the activity of other members of the SoxB1 subfamily, so the specificity of the effects on Sox2 is not fully confirmed.
2
The study does not provide definitive proof of the need for neural progenitors to achieve successful neural tissue regeneration, although it suggests that activation of Sox2+ cells is necessary.
3
The mechanisms underlying the systemic upregulation of sox2 expression levels and activation of Sox2+ cells in response to spinal cord damage are not fully elucidated.

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