Intralingual and Intrapleural AAV Gene Therapy Prolongs Survival in a SOD1 ALS Mouse Model

Abstract

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease that results in death from respiratory failure. No cure exists for this devastating disease, but therapy that directly targets the respiratory system has the potential to prolong survival and improve quality of life in some cases of ALS. The objective of this study was to enhance breathing and prolong survival by suppressing superoxide dismutase 1 (SOD1) expression in respiratory motor neurons using adeno-associated virus (AAV) expressing an artificial microRNA targeting the SOD1 gene. AAV-miR SOD1 was injected in the tongue and intrapleural space of SOD1 G93A mice, and repetitive respiratory and behavioral measurements were performed until the end stage. Robust silencing of SOD1 was observed in the diaphragm and tongue as well as systemically. Silencing of SOD1 prolonged survival by approximately 50 days, and it delayed weight loss and limb weakness in treated animals compared to untreated controls. Histologically, there was preservation of the neuromuscular junctions in the diaphragm as well as the number of axons in the phrenic and hypoglossal nerves. Although SOD1 suppression improved breathing and prolonged survival, it did not ameliorate the restrictive lung phenotype. Suppression of SOD1 expression in motor neurons that underlie respiratory function prolongs survival and enhances breathing until the end stage in SOD1 G93A ALS mice.

Beyond the Traditional Clinical Trials for Amyotrophic Lateral Sclerosis and The Future Impact of Gene Therapy

“…Indeed, differences between fast and slow IT injection of viral vector in SOD1-G93A mice were analysed and it was demonstrated that the slower one enhances transduction of spinal cord and therapeutic efficacy [ 85 ]. Alternative delivery routes of administration are also investigated, such as a combination of intralingual and intrapleural injections [ 86 ].…”

Gene delivery to the hypoglossal motor system: preclinical studies and translational potential

“…Intralingual vector delivery effectively drives gene and protein expression in the tongue [32,[45][46][47] and can reverse tongue muscle histopathology in neuromuscular disease [45][46][47]. Pompe disease is a neuromuscular disorder associated with mutations in a single gene (acid alpha glucosidase or GAA), macroglossia, dysphagia, and dysarthria [48].…”

Current Status of microRNA-Based Therapeutic Approaches in Neurodegenerative Disorders

“…Furthermore, treatment delayed weight loss and limb weakness. Despite the therapy succeeding in improving breathing and survival, it failed to amend the restrictive lung phenotype [ 110 ]. Although we consider the AAV with artificial miRNAs targeting SOD1 systems to show promising outcomes, we need to keep track of it for the next few years.…”