COLLAGEN AND STRETCH MODULATE AUTOCRINE SECRETION OF INSULIN-LIKE GROWTH-FACTOR-I AND INSULIN-LIKE GROWTH-FACTOR BINDING-PROTEINS FROM DIFFERENTIATED SKELETAL-MUSCLE CELLS
COLLAGEN AND STRETCH MODULATE AUTOCRINE SECRETION OF INSULIN-LIKE GROWTH-FACTOR-I AND INSULIN-LIKE GROWTH-FACTOR BINDING-PROTEINS FROM DIFFERENTIATED SKELETAL-MUSCLE CELLS
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DOI：
10.1074/jbc.270.5.2099
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发表时间：
1995-02-03
影响因子：
4.8
通讯作者：
VANDENBURGH, HH
中科院分区：
文献类型：
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作者：
PERRONE, CE;FENWICKSMITH, D;VANDENBURGH, HH
拉伸诱导的骨骼肌生长可能涉及胰岛素样生长因子-1(IGF-1)的自分泌增加。由于IGF-1是骨骼肌肥大的有效生长因子，并且拉伸在体内提高了IGF-1mRNA的水平。在分化的禽胸肌骨骼肌细胞的组织培养中，纳摩尔浓度的外源IGF-1在机械拉伸但不是静态培养中刺激生长，这些培养物每天释放高达100pg的内源性IGF-1/µg蛋白质，以及三种主要的IGF结合蛋白31，36和43千道尔顿(KDa)，肌纤维和成纤维细胞同时分泌IGF-1，反复拉伸/松弛分化的骨骼肌细胞在启动机械活动后的前4小时刺激IGF-1的急性释放，但在24-72小时内不引起IGF-1或其结合蛋白的长期分泌增加。与拉伸相反，改变拉伸的强度和频率对IGF-1的长期外流没有影响。将分化后的肌细胞包埋在I型胶原基质中，24-72h后IGF-1长期外流增加2-5倍，IGF结合蛋白的释放也增加2-5倍，因此，细胞外基质蛋白I型胶原和拉伸都刺激IGF-1的自分泌，但随着时间动力学的不同，这种内源性生长因子可能对骨骼肌纤维对这两种外部刺激的生长反应起重要作用。
Stretch-induced skeletal muscle growth may involve increased autocrine secretion of insulin-like growth factor-1 (IGF-1) since IGF-1 is a potent growth factor for skeletal muscle hypertrophy, and stretch elevates IGF-1 mRNA levels in vivo, In tissue cultures of differentiated avian pectoralis skeletal muscle cells, nanomolar concentrations of exogenous IGF-1 stimulated growth in mechanically stretched but not static cultures, These cultures released up to 100 pg of endogenously produced IGF-1/mu g of protein/day, as well as three major IGF binding proteins of 31, 36, and 43 kilodaltons (kDa), IGF-1 was secreted from both myofibers and fibroblasts coexisting in the muscle cultures, Repetitive stretch/relaxation of the differentiated skeletal muscle cells stimulated the acute release of IGF-1 during the first 4 h after initiating mechanical activity, but caused no increase in the long-term secretion over 24-72 h of IGF-1, or its binding proteins, Varying the intensity and frequency of stretch had no effect on the long-term efflux of IGF-1, In contrast to stretch, embedding the differentiated muscle cells in a three-dimensional collagen (Type I) matrix resulted in a 2-5-fold increase in long-term IGF-1 efflux over 24-72 h, Collagen also caused a 2-5-fold increase in the release of the IGF binding proteins, Thus, both the extracellular matrix protein type I collagen and stretch stimulate the autocrine secretion of IGF-1, but with different time kinetics, This endogenously produced growth factor may be important for the growth response of skeletal myofibers to both types of external stimuli.