Changes in oxidative stress severity and antioxidant potential during muscle atrophy and reloading in mice
Changes in oxidative stress severity and antioxidant potential during muscle atrophy and reloading in mice
复制标题
小鼠肌肉萎缩和重新加载过程中氧化应激严重程度和抗氧化潜力的变化
DOI：
10.1016/j.bbrc.2017.08.048
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发表时间：
2018
影响因子：
--
通讯作者：
Hagiwara H
中科院分区：
文献类型：
--
作者：
Katsuta W;Aihara M;Hirose N. Saito F;Hagiwara H
糖障碍复合物由两个亚基组成：细胞外α-糖障碍和跨膜β-糖障碍，它们在细胞外基质和细胞内细胞骨架之间提供了紧密的联系。先前的研究表明，在各种非肌肉组织中，43 kDa的β-三磷酸甘聚糖被基质金属蛋白酶（MMPs）蛋白水解裂解成30 kDa的片段，而在肌肉中，它被位于三磷酸甘聚糖复合物附近的肌聚糖复合物保护而不被裂解。值得注意的是，在肌糖病（肌糖缺乏型肌营养不良）患者的肌肉中检测到裂解的β-糖营养不良。利用蛋白酶抑制剂进行的体外检测表明，MMP-2和MMP-9都有助于β-三磷酸甘聚糖的裂解。然而，这一点尚未在体内进行研究。方法制备靶向MMP-2、MMP-9和γ-肌聚糖的三敲除（TKO）小鼠，检测在缺乏候选基质金属蛋白酶的情况下，肌聚糖缺乏肌肉中β-肌聚糖的裂解状态。结果不出所料，TKO小鼠的肌肉中出现了β-三磷酸甘聚糖断裂。与γ-肌聚糖单敲除小鼠相比，TKO小鼠的肌肉病理没有改善，反而恶化了。MMP-14基因在TKO小鼠和γ-肌聚糖敲除小鼠中表达上调。体外实验显示MMP-14具有裂解β-糖酐的能力。结论MMP-2和MMP-9的双重靶向作用不能阻止肌糖病变中β-三磷酸腺苷的分裂。因此，参与β-糖异常蛋白裂解的基质金属蛋白酶是多余的，MMP-14可能参与了肌糖病的发病机制。
BackgroundThe dystroglycan complex consists of two subunits: extracellular α-dystroglycan and membrane-spanning β-dystroglycan, which provide a tight link between the extracellular matrix and the intracellular cytoskeleton. Previous studies showed that 43 kDa β-dystroglycan is proteolytically cleaved into the 30 kDa fragment by matrix metalloproteinases (MMPs) in various non-muscle tissues, whereas it is protected from cleavage in muscles by the sarcoglycan complex which resides close to the dystroglycan complex. It is noteworthy that cleaved β-dystroglycan is detected in muscles from patients with sarcoglycanopathy, sarcoglycan-deficient muscular dystrophy.In vitroassays using protease inhibitors suggest that both MMP-2 and MMP-9 contribute to the cleavage of β-dystroglycan. However, this has remained uninvestigatedin vivo.MethodsWe generated triple-knockout (TKO) mice targeting MMP-2, MMP-9 and γ-sarcoglycan to examine the status of β-dystroglycan cleavage in the absence of the candidate matrix metalloproteinases in sarcoglycan-deficient muscles.ResultsUnexpectedly, β-dystroglycan was cleaved in muscles from TKO mice. Muscle pathology was not ameliorated but worsened in TKO mice compared with γ-sarcoglycan single-knockout mice. The gene expression of MMP-14 was up-regulated in TKO mice as well as in γ-sarcoglycan knockout mice.In vitroassay showed MMP-14 is capable to cleave β-dystroglycan.ConclusionsDouble-targeting of MMP-2 and MMP-9 cannot prevent cleavage of β-dystroglycan in sarcoglycanopathy. Thus, matrix metalloproteinases contributing to β-dystroglycan cleavage are redundant, and MMP-14 could participate in the pathogenesis of sarcoglycanopathy.