Myogenic and nonmyogenic cells differentially express proteinases, Hsc/Hsp70, and BAG-1 during skeletal muscle regeneration
Myogenic and nonmyogenic cells differentially express proteinases, Hsc/Hsp70, and BAG-1 during skeletal muscle regeneration
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DOI：
10.1152/ajpendo.00331.2002
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发表时间：
2003-07-01
影响因子：
5.1
通讯作者：
Freyssenet, D
中科院分区：
文献类型：
--
作者：
Duguez, S;Le Bihan, MC;Freyssenet, D
骨骼肌在受伤后具有显著的再生能力。为了确定蛋白酶、73-kDa热休克同源蛋白（Hsc70）和应激诱导的72-kDa热休克蛋白（Hsp70） （Hsc/Hsp70）以及bcl -2相关基因产物-1 （BAG-1）的表达变化是否与肌肉组织的重塑反应有关，将雄性Sprague-Dawley大鼠胫骨前肌注射0.75%的布比卡因，并在注射后3、5、7、10、14、21或35天取出（n = 5-7/组）。免疫组化分析显示，再生肌肉中存在成肌细胞（3-7天）、炎症细胞（3-7天）、变性肌纤维（3-7天）、再生肌纤维（5-10天）和生长成熟肌纤维（10-21天）。我们的生化分析记录了蛋白质水解代谢的深刻适应，其特征是基质金属蛋白酶2和9和纤溶酶原激活剂（3-14天），钙蛋白酶1和2（3-7天），组织蛋白酶B和L（3-10天）和蛋白酶体（3-14天）的酶活性显著增加。蛋白酶体活性与增殖细胞核抗原蛋白水平密切相关，提示蛋白酶体在成肌细胞增殖中起关键作用。BAG-1是Hsc/Hsp70在蛋白折叠和蛋白酶体蛋白水解界面的调节辅助因子，其表达模式并未证实蛋白酶体酶活性的变化，提示BAG-1可能促进Hsc/Hsp70的折叠能力等其他功能。总之，在本研究中，肌源性和非肌源性细胞在再生过程中所占比例的相对变化有力地支持了蛋白酶功能的多样性。
Skeletal muscle has a remarkable capacity to regenerate after injury. To determine whether changes in the expression of proteinases, 73-kDa constitutive heat shock cognate protein (Hsc70) and stress-inducible 72-kDa heat shock protein (Hsp70) (Hsc/Hsp70), and Bcl-2-associated gene product-1 (BAG-1) contribute to the remodeling response of muscle tissue, tibialis anterior muscles of male Sprague-Dawley rats were injected with 0.75% bupivacaine and removed at 3, 5, 7, 10, 14, 21, or 35 days postinjection (n = 5-7/group). The immunohistochemical analysis of desmin, alpha-actin, and developmental/neonatal myosin heavy chain expressions indicated the presence of myoblasts (days 3-7), inflammatory cells (days 3-7), degenerating myofibers (days 3-7), regenerating myofibers (days 5-10), and growing mature myofibers (days 10-21) in regenerating muscles. Our biochemical analysis documented profound adaptations in proteolytic metabolism characterized by significant increases in the enzyme activities of matrix metalloproteinases 2 and 9 and plasminogen activators (days 3-14), calpains 1 and 2 (days 3-7), cathepsins B and L (days 3-10), and proteasome (days 3-14). Proteasome activity was strongly correlated with proliferating cell nuclear antigen protein level, suggesting that proteasome played a key role in myoblast proliferation. The expression pattern of BAG-1, a regulatory cofactor of Hsc/Hsp70 at the interface between protein folding and proteasomal proteolysis, did not corroborate the changes in proteasome enzyme activity, suggesting that BAG-1 may promote other functions, such as the folding capacity of Hsc/Hsp70. Altogether, the diversity of functions attributed to proteinases in the present study was strongly supported by the relative changes in the proportion of myogenic and nonmyogenic cells over the time course of regeneration.