SIRT2 functions in aging, autophagy, and apoptosis in post-maturation bovine oocytes.
SIRT2 functions in aging, autophagy, and apoptosis in post-maturation bovine oocytes.
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DOI：
10.1016/j.lfs.2019.116639
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发表时间：
2019-09
期刊：
影响因子：
6.1
通讯作者：
Dejun Xu;X. Jiang;Huanshan He;Dingbang Liu;Li Yang-;Huali Chen;Lin Wu;G. Geng;Qingwang Li
中科院分区：
文献类型：
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作者：
Dejun Xu;X. Jiang;Huanshan He;Dingbang Liu;Li Yang-;Huali Chen;Lin Wu;G. Geng;Qingwang Li
SIRT 2参与了卵母细胞的衰老过程，但其在卵母细胞成熟后衰老中的作用尚不完全清楚。本研究的目的是评估SIRT 2在老化卵母细胞中的作用及其机制。主要方法新鲜MII卵母细胞在体外老化，分别用SIRT 2抑制剂（SirReal 2）、自噬激活剂（Rapamycin）和自噬抑制剂（3-Ma）处理24 h。研究了卵母细胞活化、胞质碎裂和纺锤体缺陷、线粒体分布、ROS水平、ATP产生、线粒体膜电位和早期凋亡。Western blotting检测LC 3-II的积累、SQSTM 1的降解和caspase-3的活性。用SirReal 2处理显著增加了卵母细胞活化、胞质碎裂和纺锤体缺陷的速率。特别是，在SirReal 2暴露的卵母细胞中观察到高ROS水平、异常线粒体分布、低ATP产生和Δ Tm丢失。进一步的分析表明，SIRT 2抑制诱导了LC 3-II的积累和SQSTM 1的降解。早期凋亡分析表明，卵母细胞老化伴随着细胞凋亡，SIRT 2抑制可增加老化卵母细胞的凋亡率。重要的是，上调自噬与雷帕霉素可以模拟SIRT 2抑制凋亡的影响，通过增加caspase-3激活，而下调自噬与3-MA可以取消这些影响通过阻断caspase-3 activation.SignificanceOur研究结果表明，SIRT 2失活是细胞衰老的关键机制，和SIRT 2抑制有助于自噬依赖的细胞凋亡后成熟卵母细胞。
AimsSirtuins have been implicated in the aging process, however, the functions of SIRT2 in post-maturation aging of oocytes are not fully understood. The purpose of the present investigation was to assess the roles of SIRT2 in aged oocytes and mechanisms involved.Main methodsThe fresh MII oocytes were aging in vitro, and treated with SIRT2 inhibitor (SirReal2), autophagy activator (Rapamycin), and autophagy inhibitor (3-Ma) for 24 h, respectively. Oocyte activation, cytoplasmic fragmentation, and spindle defects, mitochondrial distribution, ROS levels, ATP production, mitochondrial membrane potential, and early apoptosis were investigated. Western blotting was performed to determine LC3-II accumulation, SQSTM1 degradation, and caspase-3 activity.Key findingsSIRT2 expression gradually decreased in a time-dependent manner during oocyte aging. Treatment with SirReal2 significantly increased the rates of oocyte activation, cytoplasmic fragmentation, and spindle defects. In particular, the high ROS levels, abnormal mitochondrial distribution, low ATP production, and lost ΔΨm were observed in SirReal2-exposed oocytes. Further analysis revealed that LC3-II accumulation and SQSTM1 degradation were induced by SIRT2 inhibition. By performing early apoptosis analysis showed that oocyte aging was accompanied with cellular apoptosis, and SIRT2 inhibition increased apoptosis rates of aged oocytes. Importantly, upregulating autophagy with Rapamycin could mimic the effects of SIRT2 inhibition on apoptosis by increasing caspase-3 activation, whereas downregulating autophagy with 3-MA could abolish those effects by blocking caspase-3 activation.SignificanceOur results suggest that SIRT2 inactivation is a key mechanism underlying of cellular aging, and SIRT2 inhibition contributes to autophagy-dependent cellular apoptosis in post-maturation oocytes.