17β-Estradiol Induces Mitophagy Upregulation to Protect Chondrocytes via the SIRT1-Mediated AMPK/mTOR Signaling Pathway.
17β-Estradiol Induces Mitophagy Upregulation to Protect Chondrocytes via the SIRT1-Mediated AMPK/mTOR Signaling Pathway.
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17β-雌二醇通过SIRT1介导的AMPK/mTOR信号通路诱导线粒体自噬上调，从而保护软骨细胞。
DOI：
10.3389/fendo.2020.615250
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发表时间：
2020
影响因子：
5.2
通讯作者：
Guo L
中科院分区：
文献类型：
--
作者：
Mei R;Lou P;You G;Jiang T;Yu X;Guo L
越来越多的证据表明，雌激素，尤其是17β-雌二醇（17β-E2），与关节软骨代谢紊乱和绝经后骨关节炎（OA）有关。SIRT1、AMPK和mTOR被认为是关键的有丝分裂调节因子。近年来的研究表明，线粒体自噬对OA有保护作用，但分子机制尚不清楚。本研究旨在探讨17β-E2通过SIRT1介导的amp活化蛋白激酶(AMPK)/哺乳动物雷帕霉素（mTOR）信号通路对SIRT1表达的影响，以及17β-E2诱导线粒体自噬上调对软骨细胞的保护作用。分别用不同浓度的17β-E2 （0 M、1 × 10-9 M、1 × 10-8 M和1 × 10-7 M）处理ATDC5软骨细胞24小时，或在用17β-E2 （1 × 10-7 M）处理前，用或不加NAM （SIRT1抑制剂）、化合物C （AMPK抑制剂）和S1842 （mTOR抑制剂）预处理30分钟。实时荧光定量PCR、Western blotting和共聚焦免疫荧光染色检测SIRT1的表达。透射电镜观察细胞内的丝裂体，Western blotting检测AMPK/mTOR信号通路。Western blot检测有丝分裂相关蛋白p-AMPK、p-mTOR、p-JNK、p-p38。采用MTT法和5-溴-2′-脱氧尿苷（BrdU）法测定软骨细胞活力和增殖情况。这些实验独立重复3次。研究发现，17β-E2增加SIRT1、p-AMPK和线粒体自噬相关蛋白的表达水平，但降低p-mTOR的表达，进而诱导软骨细胞线粒体自噬上调。透射电镜下观察到17β- e2处理的软骨细胞线粒体自噬体增多。此外，17β-E2通过SIRT1的高表达和AMPK/mTOR信号通路的激活，提高了细胞活力和增殖能力。然而，SIRT1抑制剂烟酰胺（NAM）和AMPK抑制剂化合物C阻断了17β-E2的有益作用。总之，本研究新颖地证明了17β-E2通过sirt1介导的AMPK/mTOR信号通路诱导线粒体自噬上调以保护软骨细胞。
Increasing evidence reveals that estrogen, especially 17β-estradiol (17β-E2), is associated with articular cartilage metabolism disorder and postmenopausal osteoarthritis (OA). SIRT1, AMPK, and mTOR are regarded as critical mitophagy regulators. Recent studies have shown that mitophagy displays a protective effect against OA, but the molecular mechanism is not well known. This study aimed to investigate the effect of 17β-E2 on Sirtuin-1 (SIRT1) expression and the induction of mitophagy upregulation by 17β-E2 via the SIRT1-mediated AMP-activated protein kinase (AMPK)/mammalian target of the rapamycin (mTOR) signaling pathway to protect chondrocytes. ATDC5 chondrocytes were treated with different concentrations of 17β-E2 (0 M, 1 × 10-9 M, 1 × 10-8 M, and 1 × 10-7 M) for 24 h or pretreatment with or without NAM (SIRT1 inhibitor), Compound C (AMPK inhibitor) and S1842 (mTOR inhibitor) for 30 min prior to treatment with 17β-E2 (1 × 10-7 M) for 24 in each groups. Expression of SIRT1 was evaluated by real-time PCR, Western blotting and confocal immunofluorescence staining. Then, the mitophagosomes in cells were observed under a transmission electron microscopy (TEM), and the AMPK/mTOR signaling pathway was detected by Western blotting. The mitophagy-related proteins, p-AMPK, p-mTOR, p-JNK, and p-p38 were also identified by Western blot analysis. The chondrocytes viability and proliferation were determined by MTT and 5-Bromo-2’-deoxyuridine (BrdU) assay. These experiments were independently repeated 3 times The study found that 17β-E2 increased the expression level of SIRT1, p-AMPK, and mitophagy-related proteins but decreased p-mTOR expression, and then induced mitophagy upregulation in chondrocytes. More mitochondrial autophagosomes were observed in 17β-E2-treated chondrocytes under a transmission electron microscope. Also, 17β-E2 improved cell viability and proliferation with the higher expression of SIRT1 and activation of the AMPK/mTOR signaling pathway. However, SIRT1 inhibitor nicotinamide (NAM) and AMPK inhibitor Compound C blocked the beneficial effect of 17β-E2. In summary, this study was novel in demonstrating that 17β-E2 induced mitophagy upregulation to protect chondrocytes via the SIRT1-mediated AMPK/mTOR signaling pathway.
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影响因子：
--
作者：
Lee CH;Su SC;Chiang CF;Chien CY;Hsu CC;Yu TY;Huang SM;Shieh YS;Kao HW;Tsai CS;Hung YJ;Lin CY
通讯作者：
Lin CY
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影响因子：
13.3
作者：
Hu X;Lu Z;Yu S;Reilly J;Liu F;Jia D;Qin Y;Han S;Liu X;Qu Z;Lv Y;Li J;Huang Y;Jiang T;Jia H;Wang Q;Liu J;Shu X;Tang Z;Liu M
通讯作者：
Liu M
影响因子：
5
作者：
Dai, Chongshan;Ciccotosto, Giuseppe D.;Xiao, Xilong
通讯作者：
Xiao, Xilong
影响因子：
4.6
作者：
Jochems, C.;Islander, U.;Carlsten, H.
通讯作者：
Carlsten, H.
影响因子：
6
作者：
Khan, Mehtab;Ullah, Rahat;Kim, Myeong Ok
通讯作者：
Kim, Myeong Ok