Musde Passive Stretch-Induced Activation of Skeletal Muscle Satellite Cells

Musde 被动拉伸诱导的骨骼肌卫星细胞激活

基本信息

批准号：
12660299
负责人：
TATSUMI Ryuichi
金额：
$ 2.18万
依托单位：
KYUSHU UNIVERSITY (2001)Hokkaido University (2000)
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2000
资助国家：
日本
起止时间：
2000 至 2001
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-12660299/
关键词：
satellite cell hepatocyte growth factor HGF skeletal muscle hypertrophy activation 筋肥大伸展刺激

项目摘要

Satellite cells are normally quiescent in adult muscle, but they can be responsible for regeneration and work-induced hypertrophy of muscle fibers. Of all the growth factors studies thus far, only hepatocyte growth factor (HGF) has been shown to stimulate quiescent satellite cells to enter the cell cycle (Alien et al., 1995; Tatsumi et al., 1998). HGF protein was localized in the extracellular matrix of uninjured skeletal muscle fibers and shown to be the active agent in a crushed muscle extract. The signaling receptor for HGF is the c-met proto-oncogene, and its message and protein have been found in quiescent satellite cells (Alien et al., 1995; Cornelison ＆ Wold, 1997; Tatsumi et al., 1998). Therefore, a critical aspect of the activation of quiescent satellite cells may be the release of active HGF from its sequestration and presentation to the c- met. The purpose of this study was to determine whether satellite cells could be activated by mechanical stretch in vivo, and to explore … More the possible role of HGF in the activation mechanism.Stretch experiments were conducted in the living animal using our suspension model, which used the weight of the hind portion of 9-month-old S. D. rats to stretch the adductor and gracilis muscles on the inside of the left hind limb suspended for a period of 0.5-2.0 hr. At the end of the stretch period, rats received an ip-injection of BrdU; 16 hr later satellite cells were prepared (>97 % desmin-positive) followed by immunocytochemistry for BrdU at 30 hr post-plating. Depending on the period of stretch, BrdU-labeling and cell yield were increased two and four-fold, respectively, over the contralateral un-stretched leg or control muscle from untreated rats. Also, stretched muscle extract (SME), which was prepared from the 2 hr-stretched tissue by incubating it in PBS, showed active HGF as revealed by immunoblotting, and could activate satellite cells in culture in a dose-dependent manner; the activity of 0.5 mg SME/ml was comparable to that of exogenous HGF and could be neutralized by anti-HGF antibody. Un-stretched muscle extract did not show activating activity. These experiments provide a critical link between mechanical perturbation of skeletal muscle and biochemical signals that result in entry of satellite cells into the cell cycle. At this time, the mechanism of HGF release from muscle fibers has not been established, awaiting further studies. Less

卫星细胞通常在成年肌肉中是静止的，但它们可以负责再生和工作引起的肌肉纤维肥大。在迄今为止的所有生长因子研究中，只有肝细胞生长因子（HGF）被证明可以刺激静止的卫星细胞进入细胞周期（Alien等，1995； Tatsumi等，1998）。 HGF蛋白位于未受伤的骨骼肌纤维的细胞外基质中，并在碎肌提取物中显示为活性剂。 HGF的信号受体是C-MET原始癌基因，其信息和蛋白质已在静态卫星细胞中发现（Alien等，1995; Cornelison＆Wold，1997; Tatsumi等，1998）。因此，静态卫星细胞激活的一个关键方面可能是活性HGF从其隔离和呈现到C-MET的释放。这项研究的目的是确定是否可以通过机械拉伸在体内激活卫星细胞，并探索……更多的HGF在激活机制中的可能作用。伸直实验是使用我们的悬浮悬架模型在活的动物中进行的，我们使用我们的悬架模型，该模型使用了9个月大的S. D. D. D. D. D. D. Ress depder and the Gracilis Muscles nessecles of wewd of theew heff thewewdewews的重量。人力资源在延长期结束时，大鼠接受了BRDU的IP注射； 16小时后，制备了卫星细胞（> 97％的Desmin阳性），然后在盘子后30小时进行免疫细胞化学的BRDU。根据拉伸期，在对侧无牵引力的腿或对照肌肉中，BRDU标记和细胞的产量分别增加了两倍和四倍。同样，拉伸肌肉提取物（SME）是通过在PBS中孵育2小时拉伸组织制备的，该组织通过免疫印迹显示了活性HGF，并且可以以剂量依赖性的方式激活培养物中的卫星细胞； 0.5 mg SME/mL的活性与外源HGF相当，并且可以通过抗HGF抗体中和。未拉伸的肌肉提取物未显示活化活性。这些实验提供了骨骼肌的机械扰动与生化信号之间的关键联系，从而导致卫星细胞进入细胞周期。目前，尚未建立HGF从肌肉纤维中释放的机制，等待进一步的研究。较少的