Protein Prenylation Constitutes an Endogenous Brake on Axonal Growth

Area of Science:

• Neuroscience
• Molecular Biology
• Pharmacology

Background:

• Suboptimal axonal regeneration hinders recovery from nervous system trauma and neurodegenerative diseases.
• The intrinsic mechanisms governing axon growth are not fully understood.
• Understanding these mechanisms is crucial for developing effective regenerative therapies.

Purpose of the Study:

• To identify small molecules that promote axon outgrowth.
• To investigate the role of the mevalonate-prenylation pathway in regulating axon growth.
• To explore therapeutic strategies for enhancing neuronal regeneration.

Main Methods:

• Screened 50,400 small molecules for axon growth-promoting activity on inhibitory substrata.
• Tested the effects of statins and combined inhibition of protein prenylation enzymes (farnesyltransferase and geranylgeranyl transferase I) on neuronal growth.
• Analyzed PGGT1B levels in motor neurons from amyotrophic lateral sclerosis (ALS) patients.

Main Results:

• Statins were identified as potent promoters of axon outgrowth in both mouse and human neurons, in vitro and in vivo.
• Combined inhibition of farnesyltransferase (PFT) and geranylgeranyl transferase I (PGGT-1) also stimulated axon growth.
• Elevated PGGT1B levels were observed in motor neurons of early-onset ALS patients compared to late-onset patients, suggesting a link to disease progression.

Conclusions:

• The mevalonate-prenylation pathway acts as an endogenous brake on axonal growth.
• Inhibition of this pathway holds potential as a therapeutic strategy to accelerate neuronal regeneration.
• These findings offer a promising avenue for treating nervous system trauma and neurodegenerative conditions.