Elucidating the Pathogenic Mechanism of Spinal Muscular Atrophy Through the Investigation of UTS2

Background: Spinal muscular atrophy (SMA) is a severe neuromuscular disorder caused by mutations in the survival motor neuron 1 (SMN1) gene, resulting in progressive motor neuron loss and muscle atrophy. The urotensin 2 (UTS2) gene, located on chromosome 9q34.2, plays a significant role in cellular activities such as proliferation, apoptosis, and inflammatory responses. Notably, elevated expression levels of UTS2 have been observed in SMA patients. However, its precise contribution to disease pathogenesis remains unclear. This study aimed to investigate the effects of UTS2, which is overexpressed in SMA patients, in SMA cell models using a UTS2 inhibitor. Methods: We conducted genomic sequencing and bioinformatics analysis on clinical samples to identify proteins highly expressed in association with SMA. Using RNA interference technology, we suppressed SMN1 gene expression in bone marrow mesenchymal stem cells (MSCs) to establish an in vitro cellular model of SMA. To assess the biological consequences of SMN1 gene knockdown, we employed molecular biological techniques such as immunofluorescence, reverse transcription quantitative polymerase chain reaction (RT-qPCR), and western blotting. Furthermore, we treated the SMA cellular model with the urantide UTS2 receptor inhibitor and examined its effects on cell proliferation, apoptosis, and the expression of relevant proteins. Results: UTS2 was successfully identified as a highly expressed protein associated with SMA. A stable MSC model with SMN1 gene knockdown was established. RNA interference (RNAi) technology effectively suppressed SMN1 gene expression, leading to changes in cellular morphology and neuron-specific marker expression. Urantide intervention significantly affected both proliferation and apoptosis in the SMA cell model in a dose-dependent manner. Techniques such as the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, TUNEL fluorescence staining, and flow cytometry analysis revealed that uride decreased cell viability while increasing the proportion of apoptotic cells. Following urantide intervention, there was a notable increase in caspase-3 messenger ribonucleic acid (mRNA) levels, as well as an increase in caspase-3 protein expression, as demonstrated by immunofluorescence analysis. Conclusion: We elucidated the role of the UTS2 gene in an SMA cell model, emphasizing its dysregulation and identifying potential therapeutic targets. Urantide, a UTS2 inhibitor, had significant biological effects on the SMA cell model, indicating that it is a promising therapeutic strategy for SMA. These findings provide valuable insights for advancing drug development and clinical treatment of SMA.