Phd in CLINICAL EXPERIMENTAL NEUROSCIENCE AND PSYCHIATRY

Thesis title: Approccio terapeutico mirato con SOD1-ASO nella SLA da mutazione del gene SOD1: dal modello murino alla pratica clinica

Introduction: amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease characterized by motor neuron degeneration, leading to death within 3–5 years. In SOD1G93A transgenic mouse model, the neuromuscular junction represents the first site of degeneration, suggesting a primary role of muscle in disease pathogenesis, supporting the “dying back” theory. Aim of the study: the aim of the study is to evaluate the therapeutic effects of SOD1-ASO in the SOD1G93A mutated mouse model through intrathecal, systemic, and combined systemic + intrathecal administration, and to analyze the effect of Tofersen on patients affected by SOD1-mutated ALS (ALS-SOD1), both clinically and through the study of serum and cerebrospinal fluid parameters. Materials and methods: in 33 SOD1G93A mice, SOD1-ASO was administered at presymptomatic and symptomatic stages of the disease, evaluating functional, muscular and molecular parameters. In the clinical study, 23 patients affected by ALS were monitored with clinical, neurophysiological, respiratory parameters, and serum/cerebrospinal fluid levels of neurofilament light chain (NfL). Results: in mice, SOD1-ASO significantly improved strength, weight and mobility (p < 0.05), reduced transcripts of SOD1, Atrogin-1, MuRF-1, and denervation markers (p < 0.05) at the muscular level, and increased muscle cross-sectional area (p < 0.001), with greater effects observed in early and combined treatments. In ALS-SOD1 patients treated with Tofersen, ALSFRS-R and MRC functional scores were more stable compared to fast progressors and slow progressors. NfL levels in ALS-SOD1 subjects decreased significantly over time, more rapidly in cerebrospinal fluid and subsequently in serum (p < 0.001). Fast progressors showed significantly higher serum NfL concentrations compared to ALS-SOD1 slow progressors (p = 0.003). Conclusions: the results of this study demonstrate that treatment with SOD1-ASO has a significant therapeutic effect both in the SOD1G93A mouse model, with greater impact when administered early and in combination, and in ALS-SOD1 patients treated with Tofersen. The dual central and peripheral effect, evidenced by functional improvement and modulation of atrophy and denervation markers, suggests a synergistic action on motor neurons and skeletal muscle. The reduction of neurofilament levels in treated subjects confirms the neuroprotective effect and supports its use as a biomarker of therapeutic response. Overall, the data underline the importance of early intervention timing and open the way for future studies aimed at optimizing the systemic administration, to reduce side effects related to intrathecal administration improving long-term tolerability.