SMA-miRs: miR-181a-5p, -324-5p, -451a are overexpressed in spinal muscular atrophy skeletal muscle and serum samples

Emanuela Abiusi, Paola Infante, Cinzia Cagnoli, Ludovica Lospinoso Severini, Marika Pane, Giorgia Coratti, Maria Carmela Pera, Adele D'Amico, Federica Diano, Agnese Novelli, Serena Spartano, Stefania Fiori (+16 others)
2021 eLife  
Background:Spinal muscular atrophy (SMA) is a neuromuscular disorder characterized by the degeneration of the second motor-neuron. The phenotype ranges from very severe to very mild forms. All patients have the homozygous loss of the SMN1 gene and a variable number of SMN2 (generally two-to-four copies), inversely related with the severity. The amazing results of the available treatments have made compelling the need of prognostic biomarkers to predict the progression trajectories of patients.
more » ... eside the SMN2 products, few other biomarkers have been evaluated so far, including some miRs.Methods:We performed whole miRNome analysis of muscle samples of patients and controls (14 biopsies and 9 cultures). The levels of muscle differentially expressed miRs were evaluated in serum samples (51 patients and 37 controls) and integrated with SMN2 copies, SMN2-full length transcript levels in blood and age (SMA-score). Results:Over 100 miRs were differentially expressed in SMA muscle; three of them (HSA-miR-181a-5p, -324-5p, -451a; SMA-miRs) were significantly up-regulated in serum of patients. The severity predicted by the SMA-score was related with that of the clinical classification at a correlation coefficient of 0.87 (p<10-5).Conclusions:miRNome analyses suggest the primary involvement of skeletal muscle in SMA pathogenesis; the SMA-miRs are likely actively released in the blood flow, even if their function and target cells require to be elucidated. The accuracy of the SMA-score needs to be verified in replicative studies: if confirmed, its use could be crucial for the routine prognostic assessment, also in pre-symptomatic patients. Funding:Telethon Italia (grant # GGP12116).
doi:10.7554/elife.68054 pmid:34542403 pmcid:PMC8486378 fatcat:7in7o2oprbhsnmp4gm6g67kwju