Dysregulated expanded endocannabinoid system as therapeutic targets of amyotrophic lateral sclerosis
Amyotrophic lateral sclerosis (ALS) is a devastating neurodegenerative disease characterized by the selective loss of upper and lower motor neurons. ALS patients often manifest systemic metabolic abnormalities such as glucose intolerance. Herein, to elucidate the systemic metabolic changes related to ALS progression, we performed metabolomics analysis on the serum of ALS patients and identified several metabolites associated with the disease progression, including metabolites involved in the expanded endocannabinoid system (ECS). In particular, the levels of N-acyl taurines (NAT) were correlated with the longitudinal change in the revised ALS functional rating scale (ALSFRS-R) rating. In vitro experiments with ALS cell models and in vivo studies with SOD1G93A transgenic mice revealed that PF-04457845, a fatty amide acid hydrolase (FAAH) inhibitor, up-regulated the expanded ECS, particularly the levels of NATs and N-acyl ethanolamine and ameliorates motor neuron degeneration through the regulation of microglial polarization, synapse plasticity, and neuronal development. Our study indicates that dysregulation of the expanded ECS is associated with ALS progression and a target for novel disease-modifying therapies.