Nicotinamide Phosphoribosyltransferase Protects Against Ischemic Stroke Through SIRT1-Dependent Adenosine Monophosphate-Activated Kinase Pathway
Nicotinamide Phosphoribosyltransferase Protects Against Ischemic Stroke Through SIRT1-Dependent Adenosine Monophosphate-Activated Kinase Pathway
复制标题
DOI：
10.1002/ana.22236
复制
发表时间：
2011-02-01
影响因子：
11.2
通讯作者：
Miao, Chao-Yu
中科院分区：
文献类型：
--
作者：
Wang, Pei;Xu, Tian-Ying;Miao, Chao-Yu
目的：卒中是导致死亡和残疾的主要原因。烟酰胺磷酸核糖转移酶（Nampt）是哺乳动物烟酰胺腺嘌呤二核苷酸（NAD）（+）生物合成中的限速酶，并影响细胞命运的决定。然而，Nampt在大脑和卒中中的作用仍有待研究。
方法：我们利用慢病毒介导的Nampt过表达和敲低来调控Nampt的表达，并在体内和体外探讨Nampt对神经元在缺血应激下存活的影响。我们还使用了腺苷酸活化激酶 -α2（AMPKα2）和沉默信息调节因子2同源蛋白1（SIRT1）基因敲除小鼠来研究Nampt神经保护的潜在机制。
结果：一种高度特异性的Nampt抑制剂FK866对Nampt的抑制加重了实验性脑缺血大鼠的脑梗死，而局部脑组织中Nampt的过表达以及Nampt的酶促产物烟酰胺单核苷酸（NMN）减轻了缺血诱导的脑损伤。Nampt的过表达和敲低通过AMPK途径调节神经元的存活。在AMPKα2（-/-）神经元中，Nampt的神经保护作用消失。在神经元中，Nampt正向调节NAD（+）水平，从而控制SIRT1的活性。SIRT1与丝氨酸/苏氨酸激酶11（LKB1）（AMPK的一种上游激酶）共沉淀，并促进神经元中LKB1的去乙酰化。在SIRT1（-/-）神经元中，Nampt诱导的LKB1去乙酰化和AMPK激活消失。相反，Ca2 +/钙调蛋白依赖性蛋白激酶激酶 -β（CaMKK -β）（AMPK的另一种上游激酶）不参与Nampt的神经保护作用。更重要的是，在SIRT1（+/-）和AMPKα2（-/-）小鼠中，Nampt过表达诱导的神经保护作用消失。
解释：我们的研究结果表明，Nampt通过依赖SIRT1的AMPK途径挽救神经元免于死亡，从而对缺血性卒中起到保护作用，并提示Nampt是卒中的一个新的治疗靶点。《神经病学年鉴》2011年；69：360 - 374
Objective: Stroke is a leading cause of mortality and disability. Nicotinamide phosphoribosyltransferase (Nampt) is the rate-limiting enzyme in mammalian nicotinamide adenine dinucleotide (NAD)(+) biosynthesis and contributes to cell fate decisions. However, the role of Nampt in brain and stroke remains to be investigated.Methods: We used lentivirus-mediated Nampt overexpression and knockdown to manipulate Nampt expression and explore the effects of Nampt in neuronal survival on ischemic stress both in vivo and in vitro. We also used adenosine monophosphate (AMP)-activated kinase-alpha 2 (AMPK alpha 2) and silent mating type information regulation 2 homolog 1 (SIRT1) knockout mice to investigate the underlying mechanisms of Nampt neuroprotection.Results: Nampt inhibition by a highly-specific Nampt inhibitor, FK866, aggravated brain infarction in experimentally cerebral ischemia rats, whereas Nampt overexpression in local brain and Nampt enzymatic product nicotinamide mononucleotide (NMN) reduced ischemia-induced cerebral injuries. Nampt overexpression and knockdown regulated neuron survival via the AMPK pathway. Neuroprotection of Nampt was abolished in AMPK alpha 2(-/-) neurons. In neurons, Nampt positively modulated NAD(+) levels and thereby controlled SIRT1 activity. SIRT1 coprecipitated with serine/threonine kinase 11 (LKB1), an upstream kinase of AMPK, and promoted LKB1 deacetylation in neurons. Nampt-induced LKB1 deacetylation and AMPK activation disappeared in SIRT1(-/-) neurons. In contrast, Ca2+/calmodulin-dependent protein kinase kinase-beta (CaMKK-beta), another upstream kinase of AMPK, was not involved in the neuroprotection of Nampt. More important, Nampt overexpression-induced neuroprotection was abolished in SIRT1(+/-) and AMPK alpha 2(-/-) mice.Interpretation: Our findings reveal that Nampt protects against ischemic stroke through rescuing neurons from death via the SIRT1-dependent AMPK pathway and indicate that Nampt is a new therapeutic target for stroke. ANN NEUROL 2011;69:360-374