A Mechanistic Study of Methamphetamine Neurotoxicity: Involvement of HO-1 & MnSO

描述（由申请人提供）：项目摘要：本研究的目标是帮助弥合甲基苯丙胺（MA）神经毒性和有效治疗干预之间的差距。使用D1多巴胺（DA）受体表达神经上皮瘤细胞系（SK-N-MC），缺乏DA转运蛋白，我们已经开发了一种体外系统，模型直接针对MA毒性的突触后神经元。通过利用这个模型，我们将研究新的分子机制参与MA诱导的神经毒性，特别是血红素加氧酶-1（HO-1），活性氮（RNS）和锰超氧化物歧化酶（MnSOD）的贡献。我们推测DA刺激，通过HO-1介导的过程，导致产生RNS和神经元介导的细胞凋亡，通过硝化MnSOD。我们的假设将在以下三个具体目标进行测试：1）测试HO-1表达是否参与RNS的产生，2）测试HO-1的抑制是否减弱DA诱导的神经细胞介导的细胞凋亡，和3）确定MnSOD是否被硝化，以及用一般抗氧化剂或模拟物处理是否减弱DA诱导的硝化和/或神经细胞介导的细胞凋亡。我们将通过研究HO-1和MnSOD的活性来研究降低MA神经毒性的方法，以限制RNS的产生和随后的细胞凋亡。这将使用创新的方法来完成，例如siRNA介导的HO-1表达的敲低，或通过药理学模拟物增加MnSOD催化活性，以及利用先前已证明在其他疾病状态中具有临床相关性的化合物，例如Sn（IV）中卟啉IX。这些发现将有助于开发新的治疗方法，当作为预治疗时，将最大限度地减少对那些与MA成瘾疾病作斗争的人的进一步神经损伤。 公共卫生相关性：甲基苯丙胺是一种特别具有破坏性的药物，因为滥用甲基苯丙胺已被证明会造成局部脑损伤，相当于早期痴呆症患者的脑损伤，而且比精神分裂症患者的脑损伤更严重。为了开发有效的治疗方法来对抗甲基苯丙胺成瘾者的脑损伤，首先必须了解脑损伤是如何发生的。这项研究计划的目的是在分子水平上确定脑细胞内发生了什么，导致它们在接触甲基苯丙胺后死亡。根据这一新发现的信息，科学界将更接近于开发新的有效的甲基苯丙胺毒性治疗方法。

DESCRIPTION (provided by applicant): Project Summary: The goal of this research is to help bridge the gap between methamphetamine (MA) neurotoxicity and effective therapeutic intervention. Using a D1 dopamine (DA) receptor-expressing neuroepithelioma cell line (SK-N-MC) that lacks DA transporters, we have developed an in vitro system that models post-synaptic neurons directly targeted by MA toxicity. By utilizing this model we will study novel molecular mechanisms involved in MA-induced neurotoxicity, in particular the contribution of heme oxygenase-1 (HO-1), reactive nitrogen species (RNS) and manganese superoxide dismutase (MnSOD). We hypothesize that DA stimulation, via a process mediated by HO-1, leads to generation of RNS and mitochondrial-mediated apoptosis through nitration of MnSOD. Our hypothesis will be tested in the following three specific aims: 1) Test whether HO-1 expression is involved in RNS production, 2) Test whether inhibition of HO-1 attenuates DA-induced mitochondrial-mediated apoptosis, and 3) Determine if MnSOD is nitrated and if treatment with a general antioxidant or mimetic attenuates DA-induced nitration and/or mitochondrial-mediated apoptosis. We will investigate ways to decrease MA neurotoxicity through studies aimed at manipulation of HO-1 and MnSOD activity in order to limit RNS production and subsequent apoptosis. This will be done using innovative methods such as siRNA-mediated knock-down of HO-1 expression, or increased MnSOD catalytic activity via pharmacological mimetics as well as utilizing compounds that have previously demonstrated clinical relevance in other disease states, such as Sn (IV) mesoporphyrin IX. These findings will enable the development of new therapeutic approaches that, when given as a pre-treatment, will minimize further neurological damage to those struggling with the disease of MA addiction. PUBLIC HEALTH RELEVANCE: Methamphetamine is a particularly devastating drug as its abuse has been shown to cause localized brain damage equivalent to that seen in patients with early dementia and greater than that seen in those with schizophrenia. In order to develop effective therapeutics to combat the brain damage seen in methamphetamine addicts, it is essential to first understand how the brain damage occurs. This research proposal is aimed at determining, on a molecular level, what happens inside brain cells to cause them to die after being exposed to methamphetamine. In light of this new-found information, the scientific community will be closer to developing new and effective treatments for methamphetamine toxicity.