Astrocytes Contribute to Motor Neuron Degeneration in ALS via the TRAIL-DR5 Signaling Pathway.

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disorder characterized by the degeneration of both upper and lower motor neurons. The mechanisms underlying the selective degeneration of motor neurons in ALS remain poorly understood, underscoring the need for further investigation into the factors driving this process. In this study, we utilized ALS mouse models and an in vitro NSC34 motor neuron cell line expressing the SOD1G93A mutation to identify a novel pathogenic mechanism wherein astrocyte-secreted Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) binds to Death Receptor 5 (DR5)on motor neurons, leading to caspase-8 activation and subsequent neuronal death. Blocking DR5 with neutralizing antibodies significantly attenuated TRAIL-induced motor neuron death. These findings provide the first evidence that TRAIL may serve as a potential therapeutic target in ALS, offering new insights into the mechanisms of motor neuron degeneration in this disease.