p62/SQSTM1 but not LC3 is accumulated in sarcopenic muscle of mice.
p62/SQSTM1 but not LC3 is accumulated in sarcopenic muscle of mice.
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DOI：
10.1002/jcsm.12045
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发表时间：
2016-05
期刊：
影响因子：
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通讯作者：
Yamaguchi A
中科院分区：
文献类型：
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作者：
Sakuma K;Kinoshita M;Ito Y;Aizawa M;Aoi W;Yamaguchi A
我们研究了自噬信号通路与小鼠的骨质疏松症有关。选用青年(3月龄)和老年(24月龄)C57BL/6J小鼠。利用实时定量聚合酶链式反应、免疫印迹和免疫组织化学显微镜，我们研究了p62/SQSTM1、LC3和Beclin-1在小鼠股四头肌中随年龄的变化。老年小鼠可见明显的纤维萎缩(30%)，并可见大量中央核纤维。胞浆匀浆的Western blotting显示，衰老骨骼肌中p62/SQSTM1和Beclin-1蛋白的含量明显增加。这些蛋白质在核和膜组分中的含量随年龄的变化不明显。免疫荧光标记显示，老年小鼠股四头肌胞浆中p62/SQSTM1阳性纤维比青年小鼠多(老年组为14%，青年组为1%)。在老年肌肉中，p62/SQSTM1阳性纤维明显小于周围p62/SQSTM1阴性纤维。增龄对p62/SQSTM1和Beclin-1的mRNA水平无明显影响，但降低了Lc3的mRNA水平。在老年肌肉中，p62/SQSTM1的免疫反应部位与Beclin-1蛋白相似，但与Lc3不同。小鼠的石棺减少似乎包括自噬信号的明显缺陷。
We investigated the pathway of autophagy signaling linked to sarcopenia of mice. Young adult (3‐month) and aged (24‐ month) C57BL/6J mice were used. Using real‐time PCR, Western blotting, and immunohistochemical microscopy, we evaluated the amounts of p62/SQSTM1, LC3, and Beclin‐1 in the quadriceps muscle change with aging in mice. Marked fiber atrophy (30%) and many fibers with central nuclei were observed in the aged mice. Western blotting using homogenate of the cytosolic fraction clearly showed that the amounts of p62/SQSTM1 and Beclin‐1 proteins were significantly increased in the aged skeletal muscle. The amounts of these proteins in both nuclear and membrane fractions did not change significantly with age. Immunofluorescence labeling indicated that aged mice more frequently possessed p62/SQSTM1‐positive fibers in the cytosol in quadriceps muscle than young ones (aged: 14% vs. young: 1%). In aged muscle, p62/SQSTM1‐positive fibers were significantly smaller than the surrounding p62/SQSTM1‐negative fibers. Aging did not elicit significant changes in the mRNA levels of p62/SQSTM1 and Beclin‐1, but decreased LC3 mRNA level. In aged muscle, the location of p62/SQSTM1 immunoreactivity was similar to that of Beclin‐1 protein, but not LC3. Sarcopenia in mice appears to include a marked defect of autophagy signaling.