Musashi and Plasticity of Xenopus and Axolotl Spinal Cord Ependymal Cells

Frontiers in Cellular Neuroscience, 2018 · DOI: 10.3389/fncel.2018.00045 · Published: February 27, 2018

Regenerative Medicine Neurology Genetics

Simple Explanation

This research investigates how spinal cord cells in amphibians, specifically frogs (Xenopus) and salamanders (Axolotl), respond to injury and regenerate. It focuses on ependymal cells, which line the spinal cord and can act like stem cells. The study examines the role of Musashi (Msi) proteins, which are involved in maintaining stem cell-like properties. The researchers compare how Msi expression changes during different life stages and after spinal cord injury in both frogs and salamanders. The findings suggest that Msi-1 expression is crucial for the ability of ependymal cells to participate in spinal cord regeneration. The researchers also found that a growth factor called EGF can help maintain these cells in a regenerative state.

Study Duration

Not specified

Participants

Xenopus laevis tadpoles, Ambystoma mexicanum (Axolotl) embryos, juveniles, and adults

Evidence Level

Original Research

Key Findings

1
Msi-1 expression is high in regeneration-competent Xenopus tadpoles and is upregulated after injury in adult Axolotls, indicating its importance for spinal cord regeneration.
2
Xenopus Msi-2 has two isoforms, and the presence of a shorter isoform correlates with the loss of regeneration competence.
3
EGF maintains mesenchymal outgrowth in cultures of regeneration-competent Xenopus and injury-responsive adult Axolotl ependymal cells, supporting msi-1 expression and cell proliferation.

Research Summary

This study compares the expression of Musashi (Msi) proteins in the spinal cord ependymal cells of Xenopus laevis and Ambystoma mexicanum at different life stages and during regeneration. The researchers found that Msi-1 expression is associated with regeneration competence in both species. In Xenopus, Msi-1 is highly expressed in the spinal cord of regeneration-competent tadpoles but decreases in non-regenerating stages. In contrast, Msi-1 is absent in intact adult Axolotl spinal cord but is upregulated after injury. The study also identifies a shorter isoform of Xenopus Msi-2 that correlates with the loss of regeneration competence. Furthermore, the researchers demonstrate that epidermal growth factor (EGF) can maintain ependymal cells in a mesenchymal, regenerative state in vitro.

Practical Implications

Understanding Regeneration Mechanisms

Identifying key factors like Msi-1 and EGF can help elucidate the molecular mechanisms underlying spinal cord regeneration in amphibians.

Potential Therapeutic Targets

These findings could potentially lead to the development of new therapeutic strategies for promoting spinal cord repair in mammals, including humans.

Comparative Biology Insights

Comparing regenerative processes in different species and life stages provides valuable insights into the evolution and regulation of regeneration.

Study Limitations

1
The study focuses on two amphibian species, limiting the generalizability of the findings to other organisms.
2
The molecular mechanisms underlying the role of Msi-1 and Msi-2 in regeneration require further investigation.
3
The in vitro findings may not fully reflect the complex in vivo environment of spinal cord regeneration.

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