A transcriptomics-based drug repositioning approach to identify drugs with similar activities for the treatment of muscle pathologies in spinal muscular atrophy (SMA) models

Spinal Muscular Atrophy: Current Medications and Re-purposed Drugs

Spinal muscular atrophy (SMA) is an autosomal recessive genetic neuromuscular disorder that is characterized by gradual muscle weakness and atrophy due to the degeneration of alpha motor neurons that are present on the anterior horn of the spinal cord. Despite the comprehensive investigations conducted by global scientists, effective treatments or interventions remain elusive. The time- and resource-intensive nature of the initial stages of drug research underscores the need for alternate strategies like drug repurposing. This review explores the repurposed drugs that have shown some improvement in treating SMA, including branaplam, riluzole, olesoxime, harmine, and prednisolone. The current strategy for medication repurposing, however, lacks systematicity and frequently depends more on serendipitous discoveries than on organized approaches. To speed up the development of successful therapeutic interventions, it is apparent that a methodical approach targeting the molecular origins of SMA is strictly required.

Risk-benefit profile of onasemnogene abeparvovec in older and heavier children with spinal muscular atrophy type 1

Spinal muscular atrophy (SMA) is an autosomal recessive disorder with progressive muscle atrophy and weakness, caused by biallelic mutations in the survival motor neuron 1 (SNM1) gene. Onasemnogene abeparvovec (OA) is an approved gene replacement therapy for patients with SMA. We report on two patients with SMA type 1, weighing 20 kg, previously treated with Nusinersen, who received OA infusion at 7 years of age. To our knowledge, these two patients are the heaviest treated in the real-world and we describe their different courses after gene therapy, including liver impairment requiring long-term steroid treatment and additional immunosuppression, with only transitory improvement in functional outcomes. Our cases illustrate how careful risk-benefit consideration is required in treating older and heavier SMA patients with OA, especially in view of the multiple treatment choices available for older patients with SMA.

The SMN-ribosome interplay: a new opportunity for Spinal Muscular Atrophy therapies

The underlying cause of Spinal Muscular Atrophy (SMA) is in the reduction of survival motor neuron (SMN) protein levels due to mutations in the SMN1 gene. The specific effects of SMN protein loss and the resulting pathological alterations are not fully understood. Given the crucial roles of the SMN protein in snRNP biogenesis and its interactions with ribosomes and translation-related proteins and mRNAs, a decrease in SMN levels below a specific threshold in SMA is expected to affect translational control of gene expression. This review covers both direct and indirect SMN interactions across various translation-related cellular compartments and processes, spanning from ribosome biogenesis to local translation and beyond. Additionally, it aims to outline deficiencies and alterations in translation observed in SMA models and patients, while also discussing the implications of the relationship between SMN protein and the translation machinery within the context of current and future therapies.