Ion Channel Transporter Interactions

离子通道转运体相互作用

• 批准号: 10713968
• 负责人: Geoffrey W Abbott
• 金额: $ 35.98万
• 依托单位: UNIVERSITY OF CALIFORNIA-IRVINE
• 依托单位国家: 美国
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-02-01 至 2024-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10713968
• 关键词: Affinity; Aging; Alzheimer' s Disease; Alzheimer' s disease brain; Alzheimer' s disease model; Alzheimer' s disease pathology; Alzheimer' s disease patient; Amino Acid Transporter; Amyloid beta-Protein; Axon; Biochemical; Blood; Brain; Brain region; Cell physiology; Cells; Chinese Hamster Ovary Cell; Choroid Plexus Epithelium; Cognitive deficits; Complex; Coupled; Data; Disease model; Drug Targeting; Enzymes; Family; Feedback; Genetic; Goals; Homeostasis; Human; In Vitro; Ion Channel; Laboratories; Link; Lipids; Metabolism; Mus; Neurodegenerative Disorders; Neurofibrillary Tangles; Neurons; Neurotransmitters; Oxidative Stress; Pathogenesis; Pathology; Phosphatidylinositol 4,5-Diphosphate; Phosphatidylinositols; Population; Potassium; Process; Protein Isoforms; Proteins; Protons; Ranvier' s Nodes; Reporting; Role; Signal Transduction; Signaling Molecule; Sodium; Testing; Thiamine; Thiamine Deficiency; Thiamine Pyrophosphate; Work; Xenopus oocyte; abeta accumulation; amyloid precursor protein processing; brain tissue; glucose metabolism; in vivo; member; mitochondrial dysfunction; mouse model; myoinositol; nervous system disorder; novel; response; solute; tau Proteins; voltage

ABSTRACT Alzheimer’s disease (AD) is a neurodegenerative disorder that is increasingly prevalent in our aging populations around the world. AD is characterized by the accumulation of Amyloid-β peptide (Aβ)-containing plaques, neurofibrillary tangles, and also worsening cognitive deficits. Compelling evidence suggests that thiamine homeostasis may also be changed in AD. Reduction in thiamine diphosphate (TDP) levels and abnormal functioning of TDP-dependent key enzymes in glucose metabolism occur in the blood and brains of AD patients. Thiamine deficiency exacerbates plaque formation and alters the metabolism of Amyloid Precursor Protein Processing (APP) and/or Aβ in mouse models of AD; many thiamine-dependent processes are diminished in the brains of AD patients. We previously discovered physical interaction of voltage-gated potassium (Kv) channels with various solute transporters. We and other groups have since reported a variety of Kv channel-transporter interactions, both in vitro and in vivo, but their potential role in AD has not been established, neither have complexes of Kv channels with thiamine transporters been reported. We believe that Kv channel-transporter complexes form crucial signaling hubs facilitating tight control over highly dynamic cellular processes, and that their disruption, as we and others have shown, is associated with neurological diseases, and potentially AD. Here, building on recent preliminary data suggestive of interactions between neuronal KCNQ channels and thiamine transporters, we aim to test the hypothesis that KCNQ and/or KCNA Kv channels form reciprocally regulating complexes with the human thiamine transporters THTR-1 and/or THTR-2, which are high-affinity transporters that concentrate thiamine in cells via a downhill proton gradient. We recently demonstrated that brains of AD patients as well as those of 5XFAD (AD model) mice express significantly reduced levels of THTR-1 – building on prior work that demonstrated that thiamine homeostasis is altered in AD, and thiamine deficiency exacerbates AD pathology. In addition, we also found that various Kv channels, including KCNQ2/3, form complexes and co-localize in nodes of Ranvier with the APP early cleavage product C99, altering channel function and in the case of KCNQ2/3 causing channel inhibition. Given these links, we hypothesize that KCNA and KCNQ channels can form physical complexes with thiamine transporters THTR-1 and/or THTR-2 and thus regulate one another’s function, and we will study how they change in AD. In two Specific Aims we will first investigate in vitro existence and functional consequences of channel-transporter complex formation between KCNA, KCNQ Kv channel α subunits and thiamine transporters THTR-1 and/or THTR-2. Next, we will investigate possible changes in expression of neuronal KCNA and KCNQ channel isoforms, and their complex formation with thiamine transporters THTR-1 and/or THTR-2 in different regions of the brains of AD patients and a mouse model of the disease. At the conclusion of this project, we will have established novel channel-transporter complexes and determined whether they are altered or have the potential for a role in the pathogenesis of AD.

抽象的 阿尔茨海默病 (AD) 是一种神经退行性疾病，在老龄化人群中越来越普遍 在世界范围内，AD 的特点是含有淀粉样蛋白-β 肽 (Aβ) 的斑块的积累， 令人信服的证据表明，硫胺素会导致神经原纤维缠结，并导致认知缺陷恶化。 AD 中的体内平衡也可能发生改变，二磷酸硫胺素 (TDP) 水平降低并出现异常。 AD 患者的血液和大脑中存在葡萄糖代谢中 TDP 依赖性关键酶的功能。 硫胺素缺乏会恶化斑块形成并改变淀粉样前体蛋白的代谢 AD 小鼠模型中的加工 (APP) 和/或 Aβ；在 我们之前发现了电压门控钾 (Kv) 通道的物理相互作用。 我们和其他小组已经报道了各种 Kv 通道转运蛋白。 体外和体内的相互作用，但它们在 AD 中的潜在作用尚未确定，也没有确定 Kv 通道与硫胺素转运蛋白的复合物已被报道。 复合物形成关键的信号中枢，促进对高度动态的细胞过程的严格控制，并且 正如我们和其他人所表明的，它们的破坏与神经系统疾病以及潜在的 AD 相关。 在这里，基于最近的初步数据表明神经 KCNQ 通道和 硫胺素转运蛋白，我们的目的是检验 KCNQ 和/或 KCNA Kv 通道相互形成的假设 与人硫胺素转运蛋白 THTR-1 和/或 THTR-2 的调节复合物，具有高亲和力 我们最近证明了通过下坡质子梯度将硫胺素浓缩在细胞中的转运蛋白。 AD 患者以及 5XFAD（AD 模型）小鼠的大脑表达的 THTR-1 – 以先前的工作为基础，证明 AD 中硫胺素稳态发生改变，并且硫胺素 此外，我们还发现各种 Kv 通道，包括 KCNQ2/3， 与 APP 早期裂解产物 C99 形成复合物并共定位于 Ranvier 节点，改变通道 功能，并且在 KCNQ2/3 导致通道抑制的情况下，鉴于这些链接，我们捕获了 KCNA。 KCNQ 通道可以与硫胺素转运蛋白 THTR-1 和/或 THTR-2 形成物理复合物，从而 调节彼此的功能，我们将首先研究它们在 AD 中如何变化。 研究通道-转运蛋白复合物形成的体外存在及其功能后果 KCNA、KCNQ Kv 通道 α 亚基和硫胺素转运蛋白 THTR-1 和/或 THTR-2 接下来，我们将进行研究。 神经 KCNA 和 KCNQ 通道亚型表达的可能变化及其复杂的形成 AD 患者和小鼠大脑不同区域的硫胺素转运蛋白 THTR-1 和/或 THTR-2 在这个项目结束时，我们将建立新的通道转运蛋白。 复合物，并确定它们是否被改变或可能在 AD 的发病机制中发挥作用。