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Published on: November 25, 2014
Myelin-associated inhibitors of axon regeneration
Edith M Grados-Munro1, Alyson E Fournier
1Montréal Neurological Institute, McGill University Department of Neurology and Neurosurgery, Montréal, Québec, Canada.
Abstract:
Trauma in the adult mammalian central nervous system (CNS) has devastating clinical consequences due to the failure of injured axons to spontaneously regenerate. Over 20 years ago, pioneering work demonstrated that the non-permissive nature of CNS myelin for axon outgrowth contributes to this regenerative failure. Over the past few years, tremendous progress has been made in our understanding of the inhibitory components of CNS myelin, the axonal receptors that respond to these cues, and the intracellular signaling cascades mediating axon outgrowth inhibition. Several approaches designed to antagonize molecular mediators of axon inhibition have been tested in an effort to promote regenerative growth after CNS injury. These studies have validated the role of many candidate proteins in axon outgrowth inhibition; however, other approaches such as the generation of knockout mice for myelin-associated inhibitors have created new questions in the field.
Insights
Central nervous system (CNS) axon regeneration fails due to inhibitory myelin. Understanding these inhibitors and their receptors advances treatments for CNS injury, though new questions arise.
Area of Science:
- Neuroscience
- Regenerative Medicine
- Cell Biology
Background:
- Adult mammalian central nervous system (CNS) injuries result in permanent deficits because injured axons do not regenerate.
- CNS myelin is a major barrier to axon regeneration, inhibiting outgrowth.
- Recent advances have elucidated inhibitory myelin components, axonal receptors, and intracellular signaling pathways.
Purpose of the Study:
- To review the progress in understanding CNS myelin-associated axon growth inhibition.
- To discuss therapeutic strategies targeting these inhibitory molecules.
- To highlight remaining questions and future research directions.
Main Methods:
- Review of existing literature on CNS regeneration and myelin inhibition.
- Analysis of studies investigating molecular mediators of axon outgrowth.
- Examination of data from genetic models, such as knockout mice.
Main Results:
- Key inhibitory molecules in CNS myelin and their cognate axonal receptors have been identified.
- Signaling cascades mediating growth cone collapse and axon retraction are increasingly understood.
- Therapeutic interventions targeting specific inhibitors show promise but require further optimization.
- Genetic approaches have validated some inhibitors but also introduced new complexities.
Conclusions:
- Significant progress has been made in deciphering the molecular mechanisms underlying the failure of CNS axon regeneration.
- Targeting CNS myelin-derived inhibitors represents a viable therapeutic strategy for promoting recovery after CNS injury.
- Further research is needed to overcome remaining challenges and translate these findings into effective clinical treatments.
