中国神经再生研究(英文版) ›› 2016, Vol. 11 ›› Issue (2): 246-247.doi: 10.4103/1673-5374.177730

• 观点:退行性病与再生 • 上一篇    下一篇

多巴胺能神经元对线粒体毒素的固有高脆弱性:可能有助于帕金森病病因学研究

  

  • 收稿日期:2015-12-08 出版日期:2016-02-15 发布日期:2016-02-15

The inherent high vulnerability of dopaminergic neurons toward mitochondrial toxins may contribute to the etiology of Parkinson’s disease

Kandatege Wimalasena   

  1. Department of Chemistry, Wichita State University, Wichita, KS, USA
  • Received:2015-12-08 Online:2016-02-15 Published:2016-02-15
  • Contact: Kandatege Wimalasena, Ph.D.,Kandatege.wimalasena@wichita.edu.
  • Supported by:

    The studies cited from the author’s laboratory were carried out by his lab members Chamila Kadigamuwa, Viet Le and Sumudu Mapa. The author thanks Nivanthika Wimalasena and Shyamali Wimalasena for critical reading of the paper.

摘要:

尽管研究人员目前对帕金森病多巴胺能神经元退变的确切机制还没有深入了解,但可以确定的是线粒体功能障碍在其中发挥了中心作用。因为损伤的线粒体功能和/或暴露于线粒体毒素如鱼藤酮,百草枯,或MPTP都会导致灵长类和啮齿类动物的脑多巴胺能系统和类似帕金森变性结果加剧增强。实际上,具体的多巴胺能毒素MPTP是帕金森病的主要病因,特别是从灵长类动物和受试者直接和明确的临床和生化证据的可用性相关环境因素研究中得出其是一种最常用的模型。在几十年间,许多实验室集中研究并已引导了MPTP专用性多巴胺能毒性的通用机制。这种机制的突出特点是:(1)亲脂原毒素MPTP能够自由穿过血脑屏障进入大脑;(2)神经胶质细胞的单胺氧化酶-B可转换为终端毒素MPP +;(3)极性处理MPP +可通过有机阳离子-3被挤压转运到胞外空间;(4)突触前多巴胺转运蛋白会专门将其转化为多巴胺能神经元;(5)在多巴胺能神经元中,MPP +积聚在突触小泡和/或线粒体中;(6)线粒体中的MPP +会抑制电子传递链的线粒体复合物-Ⅰ并导致细胞ATP耗竭和过量的ROS产生进而引起细胞凋亡。虽然这种机制得到了普遍认同,但许多最近的研究结果已经开始严重挑战这一观念,即MPP +的具体多巴胺毒性中心法则主要是由于突触前多巴胺转运蛋白的特异性摄取进入多巴胺能神经元的。

Abstract:

Although the exact mechanism(s) of the degeneration of dopaminergic neurons in PD is not well understood, mitochondrial dysfunction is proposed to play a central role. This proposal is strongly strengthened by the findings that compromised mitochondrial functions and/or exposure to mitochondrial toxins such as rotenone, paraquat, or MPTP causes degeneration of the mid brain dopaminergic system and manifest symptoms similar to Parkinson’s in primates and rodents. In fact, the specific dopaminergic toxin MPTP is one of the most commonly used models in the mechanistic studies of environmental factors associated with the etiology of PD, particularly due to the availability of direct and unequivocal clinical and biochemical evidence from human and primate subjects. Several decades of intense studies in many laboratories have led to a general mechanism for thespecific dopaminergic toxicity of MPTP. The salient features of this mechanism are (a) lipophilic pro-toxin MPTP freely crosses the blood brain barrier and enters the brain; (b) in glial cells monoamine oxidase-B converts it to the terminal toxin MPP+; (c) the polar MPP+ is extruded into the extracellular space through organic cation transporter-3; (d) presynaptic dopamine transporter (DAT) takes it upspecifically into dopaminergic neurons; (e) in dopaminergic neurons, MPP+ accumulates in the synaptic vesicles and/or mitochondria; (f) mitochondrial MPP+ inhibits the mitochondrial complex-I of the electron transport chain leading to cellular ATP depletion and excessive ROS production causing apoptotic cell death. Although this mechanism is generally well accepted, numerous recent studies seriously challenge the central dogma of this proposal that the specific dopaminergic toxicity of MPP+ is primarily due to the specific uptake into dopaminergic neurons through presynaptic DAT.