Mishra Shalini, Kumar Ashish, He Yangen, Su Yixin, Singh Sangeeta, Santos Mark F, Singh Rakesh, Lee Jingyun, Furdui Cristina M, Shively Carol A, Kritchevsky Stephen B, Register Thomas C, Deep Gagan
Department of Internal Medicine-Gerontology and Geriatric Medicine, Wake Forest University School of Medicine, Winston-Salem, NC, USA.
Department of Basic Sciences, College of Osteopathic Medicine, Touro University Nevada, Henderson, NV, USA.
Geroscience. 2024 Dec 10. doi: 10.1007/s11357-024-01439-y.
Age-associated loss of muscle mass and function and subsequent mobility decline define poor health outcomes, reduced quality of life, and mortality risk. The rate and extent of aging-related muscle loss varies across older adults. It is challenging to understand the molecular pathogenesis of mobility decline, as anthropometric and imaging techniques, primarily used in muscle function assessment, do not offer much molecular information. Small extracellular vesicles (sEV) are lipid membrane-bound, nano-sized (≤ 200 nm) vesicles which carry a wide array of biomolecules as their cargo. sEV contain cell/tissue-specific signatures on their surface and can be isolated from biofluids. These properties pose sEV as a minimally invasive means to monitor the functional and biological health of difficult-to-access tissues, establishing them as a promising liquid biopsy tool. Here, we first isolated skeletal muscle-derived sEV (sEV) from the serum of vervet monkeys (16 to < 25 years old) using alpha sarcoglycan (SGCA) as a muscle-specific sEV surface marker. sEV were extensively characterized for size, concentration, purity, and specificity. Further, sEV isolated from young (11-15 years) and old (25-29 years) monkeys' serum were characterized for oxidized proteins by mass spectrometry and miRNAs by small-RNAseq. Notably, the analysis of oxidized proteins indicated perturbation of metabolic pathways, actin cytoskeleton, muscle cytoskeleton regulation, and HIF-1 signaling in older monkeys. Furthermore, small-RNAseq analysis identified differential expression of several miRNAs regulating metabolic pathways, inflammation, and stress signaling. Altogether, these results suggest that it is feasible to isolate sEV and use them to identify molecular biomarkers that reflect the physiological state of muscle tissue.
与年龄相关的肌肉质量和功能丧失以及随之而来的活动能力下降，预示着健康状况不佳、生活质量降低和死亡风险增加。老年人中与衰老相关的肌肉流失的速度和程度各不相同。了解活动能力下降的分子发病机制具有挑战性，因为主要用于肌肉功能评估的人体测量和成像技术并不能提供太多分子信息。小细胞外囊泡（sEV）是脂质膜结合的纳米级（≤200 nm）囊泡，其携带各种各样的生物分子作为其货物。sEV在其表面含有细胞/组织特异性特征，并且可以从生物流体中分离出来。这些特性使sEV成为监测难以获取的组织的功能和生物学健康的微创手段，使其成为一种有前途的液体活检工具。在这里，我们首先使用α-肌聚糖（SGCA）作为肌肉特异性sEV表面标志物，从黑长尾猴（16至<25岁）的血清中分离出骨骼肌来源的sEV。对sEV的大小、浓度、纯度和特异性进行了广泛表征。此外，通过质谱分析从幼年（11 - 15岁）和老年（25 - 29岁）猴子血清中分离出的sEV的氧化蛋白，并通过小RNA测序分析miRNA。值得注意的是，氧化蛋白分析表明老年猴子的代谢途径、肌动蛋白细胞骨架、肌肉细胞骨架调节和HIF-1信号传导受到干扰。此外，小RNA测序分析确定了几种调节代谢途径、炎症和应激信号传导的miRNA的差异表达。总之，这些结果表明，分离sEV并使用它们来鉴定反映肌肉组织生理状态的分子生物标志物是可行的。
