Reduction of AMP-activated protein kinase alpha2 increases endoplasmic reticulum stress and atherosclerosis in vivo.
Reduction of AMP-activated protein kinase alpha2 increases endoplasmic reticulum stress and atherosclerosis in vivo.
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DOI：
10.1161/circulationaha.109.900928
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发表时间：
2010-02-16
期刊：
影响因子：
37.8
通讯作者：
Zou MH
中科院分区：
文献类型：
--
作者：
Dong Y;Zhang M;Liang B;Xie Z;Zhao Z;Asfa S;Choi HC;Zou MH
异常内质网（ER）应激与包括动脉粥样硬化在内的多种心血管疾病有关。异常ER应激发展的机制知之甚少。本研究旨在探讨腺苷酸活化蛋白激酶（AMPK）功能障碍是否导致异常ER应激和动脉粥样硬化。使用来自AMPK缺陷小鼠的人脐静脉内皮细胞（HUVEC）和小鼠主动脉内皮细胞（MAEC），使用蛋白质印迹法评估ER应激水平。AMPKα2表达降低可显著增加HUVEC的ER应激水平。此外，来自AMPKα2敲除小鼠（AMPKα2−/−）的MAEC具有更高的ER应激标志物表达和细胞内Ca 2+水平增加。这些表型被废除的腺病毒过表达的组成型活性AMPK突变体（Ad-AMPK-CA）或切除肌内质网钙ATP酶（SERCA）。抑制SERCA诱导的内皮细胞中的ER应激。此外，AMPKα表达的减少抑制了SERCA活性。此外，AMPKα2−/−小鼠MAEC中SERCA活性显著降低，同时SERCA氧化增加。这两种表型都被腺病毒过表达的Ad-AMPK-CA所消除。此外，tempol恢复了SERCA活性并降低了氧化的SERCA水平，显著降低了AMPKα2−/−小鼠MAEC中的ER应激水平。最后，口服牛磺熊去氧胆酸（TUDCA）（一种抑制ER应激的化学伴侣）可显著降低LDL受体和AMPKα2缺陷小鼠的ER应激和主动脉病变发展。这些结果表明，AMPK功能作为一个生理抑制ER应激通过维持SERCA活性和细胞内Ca 2+稳态。
Aberrant endoplasmic reticulum (ER) stress is associated with several cardiovascular diseases including atherosclerosis. The mechanism by which aberrant ER stress develops is poorly understood. This study investigated whether dysfunction of AMP-activated protein kinase (AMPK) causes aberrant ER stress and atherosclerosis in vivo. Human umbilical vein endothelial cells (HUVEC) and mouse aortic endothelial cells (MAEC) from AMPK-deficient mice were used to assess the level of ER stress using western blotting. Reduction of AMPKα2 expression significantly increased the level of ER stress in HUVEC. In addition, MAEC from AMPKα2 knockout mice (AMPKα2−/−) had higher expression of markers of ER stress and increased levels of intracellular Ca2+. These phenotypes were abolished by adenovirally overexpressing constitutively active AMPK mutants (Ad-AMPK-CA) or by transfecting sarco-endoplasmic reticulum calcium ATPase (SERCA). Inhibition of SERCA induced ER stress in endothelial cells. Furthermore, reduction of AMPKα expression suppressed SERCA activity. In addition, SERCA activity was significantly reduced concomitantly with increased oxidation of SERCA in MAEC from AMPKα2−/− mice. Both of these phenotypes were abolished by adenovirally overexpressing Ad-AMPK-CA. Furthermore, tempol, which restored SERCA activity and decreased oxidized SERCA levels, markedly reduced the level of ER stress in MAEC from AMPKα2−/− mice. Finally, oral administration of tauroursodeoxycholic acid (TUDCA), a chemical chaperone that inhibits ER stress, significantly reduced both ER stress and aortic lesion development in LDL receptor and AMPKα2 deficient mice. These results suggest that AMPK functions as a physiological suppressor of ER stress by maintaining SERCA activity and intracellular Ca2+ homeostasis.