Metabolic activation of AMP kinase in vascular smooth muscle
Metabolic activation of AMP kinase in vascular smooth muscle
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DOI：
10.1152/japplphysiol.00075.2004
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发表时间：
2005-01-01
影响因子：
3.3
通讯作者：
Hale, CC
中科院分区：
文献类型：
--
作者：
Rubin, LJ;Magliola, L;Hale, CC
AMP激活激酶（AMPK）是一种高度保守的异源三聚体激酶，其作为代谢主开关来协调参与碳水化合物和脂肪代谢的细胞酶，所述碳水化合物和脂肪代谢调节ATP的保存和合成。AMPK在增加AMP与ATP比率的条件下被激活，例如运动和代谢应激。在本研究中，我们探讨AMPK是否在血管平滑肌中表达并被代谢应激激活。用2-脱氧葡萄糖（10 mM）加N-2（N-2-2DG）对剥脱内皮的猪颈动脉段进行代谢挑战。这些血管表现出AMPK活性在1分钟内迅速增加，在20分钟时接近最大值。返回到正常生理盐水时AMPK失活在1分钟内类似于50%，并在5分钟时完全恢复。α（1）和α（2）催化亚基的免疫沉淀，然后对[P] Thr（172）-AMPK进行免疫印迹分析，表明α（1）-AMPK负责所有活动。在颈动脉平滑肌中几乎没有检测到α 2-AMPK。AMPK活性不增加收缩激动剂（内皮素-1）或报告的AMPK激活剂5-氨基咪唑-4-甲酰胺呋喃核糖苷（2 mM），二甲双胍（2 mM），或苯丙氨酸（0.2 mM）。N-2-2DG激活AMPK与内皮素诱导力的快速显著降低以及Akt和Erk 1/2磷酸化的降低相关。这些数据表明AMPK在血管平滑肌中的表达与横纹肌不同，代谢应激后AMPK的激活和失活迅速发生，并与调节平滑肌收缩的信号通路有关
AMP-activated kinase ( AMPK) is a highly conserved heterotrimeric kinase that functions as a metabolic master switch to coordinate cellular enzymes involved in carbohydrate and fat metabolism that regulate ATP conservation and synthesis. AMPK is activated by conditions that increase AMP-to-ATP ratio, such as exercise and metabolic stress. In the present study, we probed whether AMPK was expressed in vascular smooth muscle and would be activated by metabolic stress. Endothelium-denuded porcine carotid artery segments were metabolically challenged with 2-deoxyglucose ( 10 mM) plus N-2 (N-2-2DG). These vessels exhibited a rapid increase in AMPK activity by 1 min that was near maximal by 20 min. AMPK inactivation on return to normal physiological saline was similar to 50% in 1 min and fully recovered by 5 min. Immunoprecipitation of the alpha(1)- and alpha(2)-catalytic subunit followed by immunoblot analysis for [P] Thr(172)-AMPK indicates that alpha(1)-AMPK accounts for all activity. Little if any alpha(2)-AMPK was detected in carotid smooth muscle. AMPK activity was not increased by contractile agonist (endothelin-1) or by the reported AMPK activators 5-aminoimidazole-4- carboxamide ribofuranoside ( 2 mM), metformin ( 2 mM), or phenformin (0.2 mM). AMPK activation by N-2-2DG was associated with a rapid and pronounced reduction in endothelin-induced force and reduced phosphorylation of Akt and Erk 1/2. These data demonstrate that AMPK expression differs in vascular smooth muscle compared with striated muscles and that activation and inactivation after metabolic stress occur rapidly and are associated with signaling pathways that may regulate smooth-muscle contraction