Inactivated AMPK-α2 promotes the progression of diabetic brain damage by Cdk5 phosphorylation at Thr485 site
Inactivated AMPK-α2 promotes the progression of diabetic brain damage by Cdk5 phosphorylation at Thr485 site
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灭活的 AMPK-α2 通过 Thr485 位点的 Cdk5 磷酸化促进糖尿病脑损伤的进展
DOI：
10.1016/j.biochi.2019.11.010
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发表时间：
2020-01-01
期刊：
影响因子：
3.9
通讯作者：
Li, Xian-Hui
中科院分区：
文献类型：
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作者：
Li, Yan;Xiang, Qiong;Li, Xian-Hui
糖尿病患者脑能量代谢的变化，包括胰岛素抵抗增加和线粒体功能障碍，与糖尿病相关的神经退行性变密切相关，并与早期认知障碍有关。本研究的目的是检测细胞周期蛋白依赖性激酶5（Cdk 5）调控的特异性磷酸化Thr 485-AMP激活蛋白激酶（AMPK-α 2）是否发挥AMPK-α 2的抑制作用，这可能与糖尿病脑损伤的加速发展有关。在这里，我们使用GK大鼠，2型糖尿病的动物模型，在体内研究和进行体外激酶测定，高糖治疗，磷酸化突变和蛋白表达的HEK-293 T和HT-22细胞系。在体外，结果表明，鼠野生型AMPK-α 2在（S/T）PX（K/H/R）磷酸化共有序列处被Cdk 5磷酸化，这与AMPK-α 2活性降低相关。令人惊讶的是，AMPK-α 2中Thr 485突变为丙氨酸导致Cdk 5效应消失，表明Thr 485磷酸化对Cdk 5抑制AMPK-α 2至关重要。此外，这些改变AMPK-α 2-磷酸化和活性诱导的Cdk 5是特定的Thr 485。GK大鼠AMPK-α 2磷酸化Thr 485的增加导致AMPK-α 2活性降低，这与神经元凋亡有关。在高糖处理后，与AMPK-α 2（WT）相比，AMPK-α 2（T485 A）HT-22细胞的存活率降低。GK大鼠和HT-22细胞中p-CREB、SNAP 25、synaptophysin和synapsin-1表达下调。同时，用特异性Cdk 5抑制剂（roscovitine）或抗糖尿病AMPK-α 2（-）抑制剂（二甲双胍）预处理可以恢复神经元蛋白表达的改变。我们的研究结果表明，Cdk 5介导的磷酸化的AMPK-α 2的Thr 485可能参与糖尿病脑损伤的发病机制。(C)2019 Elsevier B. V.和法国生物化学与生物分子学会（SFBBM）。All rights reserved.
Changes in brain energy metabolism in diabetes mellitus, including increased insulin resistance and mitochondrial dysfunction, are critically involved in diabetes-related neurodegeneration, and associate with early cognitive impairment as well. The aim of this study is to detect the specific phosphorylated-Thr485- AMP-activated protein kinase (AMPK-alpha 2), regulated by cyclin-dependent kinase 5 (Cdk5) paly the inhibitory functional role of AMPK-alpha 2, Which is maybe the link to the accelerated diabetic brain damage progression. Here, we used GK rats, the type 2 diabetic animal model for in vivo studies and performed In vitro kinase assay, high glucose treatment, -phosphorylated mutation and protein expression in both HEK-293T and HT-22 cell lines. In vitro, the results show that murine wild-type AMPK-alpha 2 was phosphorylated by Cdk5 at a (S/T)PX(K/H/R) phosphorylation consensus sequence, which was associated with decreased AMPK-alpha 2 activity. Surprisingly, mutation of Thr485 to alanine in AMPK-alpha 2 results in the abolished Cdk5 effects, demonstrating that Thr485-phosphorylation is critical to AMPK-alpha 2 inhibition by Cdk5. In addition, these alterations in AMPK-alpha 2-phosphorylation and -activity induced by Cdk5 is specific at Thr485. Furthermore, in GK rats, the increased phosphorylated- Thr 485 of AMPK-alpha 2 results in the decreased AMPK-alpha 2 activity, which is correlated with the apoptosis of neurons in hippocamps. After high glucose treatment, the decreased survival showed in AMPK-alpha 2(T485A) HT-22 cells compared to AMPK-alpha 2(WT). The down-regulated of p-CREB, SNAP25, synaptophysin as well as synapsin-1were shown in both GK rats and HT-22 cell line. Meanwhile, pre-treated with either the specific Cdk5-inhibitor (roscovitine) or the antidiabetic AMPK-alpha 2(-)inhibitor (metformin) could restore the alterations in neuronal protein expression. Our results suggest that Cdk5-mediated phosphorylated- Thr485 in AMPK-alpha 2 may be involved in the pathogenesis of diabetic brain damage. (C) 2019 Elsevier B.V. and Societe Francaise de Biochimie et Biologie Moleculaire (SFBBM). All rights reserved.