Song Jia, Yang Mengmeng, Xia Longqing, Wang Liming, Wang Kewei, Xiang Yingyue, Cheng Jun, Chen Jun, Liu Jidong, Zhao Ruxing, Liu Fuqiang, Sun Zheng, Hou Xinguo, Zang Nan, Chen Li
Department of Endocrinology and Metabolism, Qilu Hospital of Shandong University, Jinan, Shandong, China.
Department of Clinical Laboratory, Shandong Engineering & Technology Research Center for Tumor Marker Detection, The Second Hospital of Shandong University, Jinan, Shandong, China.
J Cachexia Sarcopenia Muscle. 2025 Feb;16(1):e13717. doi: 10.1002/jcsm.13717.
Muscle atrophy is associated with Type 2 diabetes mellitus, which reduces the quality of life and lacks effective treatment strategies. Previously, it was determined that human umbilical cord mesenchymal stromal cell (hucMSC)-derived exosomes (EXOs) ameliorate diabetes-induced muscle atrophy. However, the systemic application of EXOs is less selective for diseased tissues, which reduces their efficacy and safety associated with their nonspecific biological distribution in vivo. Therefore, improving exosomal targeting is imperative. In this study, a skeletal muscle-specific aptamer (Apt) was used to explore the effects of Apt-functionalized EXOs derived from hucMSCs in diabetes-associated muscle atrophy and its specific mechanisms.
Diabetic db/db mice and C2C12 myotubes were used to explore the effects of MSC-EXOs or Apt-EXOs in alleviating muscle atrophy. Grip strength, muscle weight and muscle fibre cross-sectional area (CSA) were used to evaluate skeletal muscle strength and muscle mass. Western blot analysis of muscle atrophy signalling, including MuRF1 and Atrogin 1 and the mitochondrial complex and Seahorse analysis were performed to investigate the underlying mechanisms of MSC-EXOs or Apt-EXOs on muscle atrophy.
MSC-EXOs increased grip strength (p = 0.0002) and muscle mass (p = 0.0044 for tibialis anterior (TA) muscle, p = 0.002 for soleus (SO) muscle) in db/db mice. It also increased the CSA of muscle fibres (p = 0.0011 for all fibres, p = 0.0036 for slow muscle fibres and p = 0.0089 for fast muscle fibres) and the percentage of slow-to-fast muscle fibres (p = 0.0109). However, Atrogin 1 (p = 0.0455) and MuRF1 expression (p = 0.0168) was reduced. MSC-EXOs activated SIRT1/FoxO1/3a signalling and enhanced mitochondrial function in db/db mice and C2C12 myotubes. SIRT1 knockdown decreased the beneficial antiatrophic effects of MSC-EXOs. Additionally, Apt conjugation increased the effect of MSC-EXOs on muscle atrophy and myofiber-type transition (p = 0.0133 for grip strength, p = 0.0124 for TA muscle weight, p = 0.0008 for SO muscle weight, p < 0.0001 for CSA of all muscle fibres, p = 0.0198 for CSA of slow muscle fibres, p = 0.0213 for CSA of fast muscle fibres, p = 0.011 for percentage of slow-fast muscle fibres, p = 0.0141 for Atrogin 1 expression and p = 0.005 for MuRF1 expression).
The results suggest that hucMSC-derived exosomes ameliorate diabetes-associated muscle atrophy by enhancing SIRT1/FoxO1/3a-mediated mitochondrial function and that Apt conjugation strengthens the effects of MSC-EXOs on muscle atrophy. These findings demonstrate the therapeutic potential of muscle-targeted MSC-EXOs for the treatment of muscle atrophy.
肌肉萎缩与2型糖尿病相关，这降低了生活质量且缺乏有效的治疗策略。此前已确定人脐带间充质基质细胞（hucMSC）衍生的外泌体（EXOs）可改善糖尿病诱导的肌肉萎缩。然而，外泌体的全身应用对患病组织的选择性较低，这降低了其疗效以及与体内非特异性生物分布相关的安全性。因此，改善外泌体靶向性势在必行。在本研究中，使用骨骼肌特异性适配体（Apt）来探究hucMSC来源的Apt功能化外泌体对糖尿病相关肌肉萎缩的影响及其具体机制。
使用糖尿病db/db小鼠和C2C12肌管来探究间充质干细胞外泌体（MSC-EXOs）或Apt-EXOs在减轻肌肉萎缩方面的作用。握力、肌肉重量和肌纤维横截面积（CSA）用于评估骨骼肌力量和肌肉质量。对包括MuRF1和Atrogin 1在内的肌肉萎缩信号通路进行蛋白质印迹分析以及线粒体复合物分析和海马分析，以研究MSC-EXOs或Apt-EXOs对肌肉萎缩的潜在作用机制。
MSC-EXOs增加了db/db小鼠的握力（p = 0.0002）和肌肉质量（胫前肌（TA）p = 0.0044，比目鱼肌（SO）p = 0.002）。它还增加了肌纤维的CSA（所有纤维p = 0.0011，慢肌纤维p = 0.0036，快肌纤维p = 0.0089）以及慢肌纤维向快肌纤维的百分比（p = 0.0109）。然而，Atrogin 1（p = 0.0455）和MuRF1表达（p = 0.0168）降低。MSC-EXOs激活了db/db小鼠和C2C12肌管中的SIRT1/FoxO1/3a信号通路并增强了线粒体功能。SIRT1基因敲低降低了MSC-EXOs的有益抗萎缩作用。此外，Apt偶联增强了MSC-EXOs对肌肉萎缩和肌纤维类型转变的作用（握力p = 0.0133，TA肌肉重量p = 0.0124，SO肌肉重量p = 0.0008，所有肌纤维CSA p < 0.0001，慢肌纤维CSA p = 0.0198，快肌纤维CSA p = 0.0213，慢-快肌纤维百分比p = 0.011，Atrogin 1表达p = 0.0141，MuRF1表达p = 0.005）。
结果表明，hucMSC来源的外泌体通过增强SIRT1/FoxO1/3a介导的线粒体功能来改善糖尿病相关的肌肉萎缩，并且Apt偶联增强了MSC-EXOs对肌肉萎缩的作用。这些发现证明了肌肉靶向的MSC-EXOs在治疗肌肉萎缩方面的治疗潜力。
