Regulation of the energy sensor AMP-activated protein kinase in the kidney by dietary salt intake and osmolality
Regulation of the energy sensor AMP-activated protein kinase in the kidney by dietary salt intake and osmolality
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DOI：
10.1152/ajprenal.00190.2004
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发表时间：
2005-03-01
影响因子：
4.2
通讯作者：
Power, DA
中科院分区：
文献类型：
--
作者：
Fraser, S;Mount, P;Power, DA
AMP激活的蛋白激酶(AMPK)是细胞能量代谢的关键控制者。我们研究了盐处理对其在肾脏中的表达和调控。免疫沉淀和免疫印迹显示，肾脏中存在α催化亚基，与β(2)亚基和伽马(1)或伽马(2)亚基有关。免疫组织化学染色显示，激活的AMPK表达于Henle环皮质粗大升支的顶面，包括致密黄斑和部分远端曲管。激活的AMPK也表达于皮质和髓质集合管的基底外侧表面以及远曲小管的某些部分。在接受高盐饮食的动物中，AMPK活性增加了25%，这在pThr(172)的Western blotting中得到了证实。低盐饮食与AMPKα亚单位水平降低有关，该亚单位在苏氨酸(172)上高度磷酸化。令人惊讶的是，低盐和高盐介质都瞬时激活了致密斑细胞系MMDD1中的AMPK，这一影响是由于渗透压的变化，而不是Na+或Cl-浓度的变化。因此，这项研究证明了体内高盐和低盐摄入量对AMPK的调节，并表明该激酶在肾脏内渗透压变化的反应中发挥了作用。
The AMP-activated protein kinase (AMPK) is a key controller of cellular energy metabolism. We studied its expression and regulation by salt handling in the kidney. Immunoprecipitation and Western blots of protein lysates from hole rat kidney using subunit-specific antibodies showed that alpha-catalytic subunit is expressed in the kidney, associated with the beta(2)- and either gamma(1)- or gamma(2)-subunits. Activated AMPK, detected by immunohistochemical staining for phospho-Thr(172) AMPK (pThr(172)), was expressed on the apical surface of the cortical thick ascending limb of the loop of Henle, including the macula densa, and some parts of the distal convoluted tubule. Activated AMPK was also expressed on the basolateral surface of the cortical and medullary collecting ducts as well as some portions of the distal convoluted tubules. AMPK activity was increased by 25% in animals receiving a high-salt diet, and this was confirmed by Western blotting for pThr(172). Low-salt diets were associated with reduced levels of the a-subunit of AMPK, which was highly phosphorylated on Thr(172). Surprisingly, both low- and high-salt media transiently activated AMPK in the macula densa cell line MMDD1, an effect due to changes in osmolality, rather than Na+ or Cl- concentration. This study, therefore, demonstrates regulation of AMPK by both a high- and a low-salt intake in vivo and suggests a role for the kinase in the response to changes in osmolality within the kidney.