Abstract
DNA-based therapeutics have revolutionized the treatment gap for rare inherited conditions by providing precise strategies targeting the root cause of disease. Inherited neuropathies, known as Charcot-Marie-Tooth (CMT) disease, are one of the most common rare Mendelian disease groups in neurology. CMT is characterized by heterogenous genetic etiology and clinical subphenotypes. Axonal forms of CMT (CMT2) are defined by axonal degeneration, trafficking impairments, and insult to the lower motor neurons. Point mutations in NEFL are responsible for CMT2E, with a serine substitution (p.N98S) being one of the most common pathogenic variants. A precise mechanism responsible for axonal degeneration in CMT2EN98S has yet to be described, however, aberrant axonal NF-L distribution and accumulation has been observed. No current disease mitigating treatment exist. However, recent progress in antisense oligonucleotide (ASO) treatment strategies provide a viable answer. Knockdown ASOs mechanistically function through ribonuclease-mediated clearance of targeted RNA transcripts via hybridizing of a short DNA sequence with a chemically engineered backbone. Here we elucidate pathomechanistic changes contributing to variant specific molecular phenotypes in CMT2E using a patient-derived induced pluripotent stem cell (iPSC)-motor neuron model. Using an ASO treatment strategy targeting the heterozygous gain-of-function p.N98S variant, we aimed to resolve molecular phenotypic changes observed in the patient-derived iPSC-induced motor neuron model. To determine ASO therapeutic potential, we used well established and emerging biomarkers of peripheral nervous system axonal degeneration as well as hallmark molecular phenotypic changes in CMT2E in-vitro systems. Our findings have demonstrated a significant decrease in clinically relevant biomarkers, presenting the first potential treatment strategy for an otherwise untreatable inherited disorder.