PRECLINICAL STUDIES INVESTIGATING NOVEL TARGETS FOR THE TREATMENT OF AMYOTROPHIC LATERAL SCLEROSIS (ALS)

Amyotrophic Lateral Sclerosis (ALS) is a fatal neurodegenerative disorder characterized by the progressive loss of motor neurons with no effective treatments. ALS pathology is multifaceted, involving protein aggregation, excitotoxicity, and synaptopathy. This project provides a preclinical investigation of ML4-10, a novel compound provided by Macquarie University that has demonstrated long-term neuroprotective effects, including improved motor function and grip strength in ALS mouse models. The primary objective of this study is to elucidate the acute, short-term effects of ML4-10 on motor neuron networks. Using whole-cell patch-clamp electrophysiology, we recorded the electrical properties of spinal cord motor neurons from wild-type (C57BL/6J) mice in the presence and absence of 1.5 µM ML4-10. We focused on two primary parameters: intrinsic excitability and presynaptic inputs. To assess intrinsic excitability, frequency-current (F-I) relationships were analysed via current-clamp recordings. No significant differences in the F-I relationship were observed following ML4-10 application, suggesting that its short-term mechanism does not involve the direct modulation of intrinsic neuronal excitability. However, voltage-clamp recordings revealed a consistent decline in the frequency of both mixed and inhibitory postsynaptic currents (PSCs). This indicates that ML4-10 reduces the total synaptic input received by motor neurons. To determine whether this reduction stems from decreased presynaptic neuronal activity or changes at the synaptic level, our ongoing experiments are utilizing tetrodotoxin (TTX) to isolate action potential-independent synaptic events. By providing a comprehensive electrophysiological characterization, this research aims to validate ML4-10 as a therapeutic candidate and establish the mechanistic foundation for its potential in treating ALS.