SMN deficiency contributes to osteoporosis in spinal muscular atrophy by impairing Snap23 meditated muscle-derived extracellular vesicle secretion

作者：Lin W, Sui W, Deng Y, Chen J, Shao X, Huang Z, Wei W, Cheng L, Zhang X, Hu R, Yang J, Li B, Yang J · 发表于：Journal of translational medicine · 年份：2026 · DOI：10.1186/s12967-026-08475-6 · 研究领域：Muscle-bone crosstalk、Muscle-derived extracellular vesicles、Osteoporosis、SNAREs、Spinal muscular atrophy

BACKGROUND: Spinal muscular atrophy (SMA), caused by mutations in survival motor neuron 1 (SMN1), presents with severe muscle atrophy and prevalent osteoporosis. Transcriptomic profiling of patient muscle biopsies revealed enrichment of extracellular vesicle genes, yet the contribution of SMA-EVs to SMA-associated bone loss and their link to SMN deficiency remain undefined. METHODS: Clinical CT/MRI images of SMA and control subjects were acquired to quantify osteoporosis and muscle atrophy. SMA model mice (Smn1hSMN2/hSMN2ROSA26hSMN2/+) were phenotyped at 6 weeks by micro-CT and histology. EVs were isolated from muscles, validated (western blot, transmission electron microscope, nano-flow cytometry, BCA protein assay), and compared between genotypes. DiL-labelled EV biodistribution was tracked in vivo; uptake by BMSCs/BMMs was confirmed by confocal microscopy. Cytotoxicity was assessed by live/dead staining. Dose-response experiments evaluated the osteogenic and anti-osteoclastic activity of SMA-EVs. Comparison of the effects of SMA-EVs and CON-EVs were performed with adequate doses in vitro and in vivo, followed by EV replenishment in SMA mice. Osteogenic and osteoclastogenic gene expression was quantified by qPCR; ALP activity by ELISA. Bone and cell parameters were assessed by HE staining, TRAP staining, COL-1 immunofluorescence staining, and micro-CT. RNA-seq data were validated by Western blot. Lentiviral shRNA and over-expression plasmids were used to generate muscle ce...