Targeting AMPA Receptor Splicing as a Therapeutic Approach for ALS

靶向 AMPA 受体剪接作为 ALS 的治疗方法

• 批准号: 8110325
• 负责人: GORDON J LUTZ
• 金额: $ 7.7万
• 依托单位: DREXEL UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-06-15 至 2011-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8110325
• 关键词: AMPA Receptors; Affect; Amyotrophic Lateral Sclerosis; Brain; Brain Stem; Calcium; Cannulas; Cells; Cessation of life; Diagnosis; Disease; Dose; Electrophysiology (science); Enhancers; Epilepsy; Familial Amyotrophic Lateral Sclerosis; Glutamates; Human; In Vitro; Ion Channel; Lead; Measures; Mediating; Motor Cortex; Motor Neurons; Mus; Nerve Degeneration; Neurons; Nucleic Acids; Parkinsonian Disorders; Patients; Production; Property; Protein Isoforms; RNA Editing; RNA Splicing; Relative (related person); Resistance; Spinal; Spinal Cord; Stroke; Testing; Therapeutic; Time; Transcript; Traumatic Brain Injury; Variant; base; desensitization; design; drug development; drug discovery; excitotoxicity; in vivo; mRNA Precursor; neuroprotection; novel; novel therapeutics; painful neuropathy; protein expression; public health relevance; response; synaptic function

DESCRIPTION (provided by applicant): Amyotrophic lateral sclerosis (ALS) is characterized by the progressive and selective loss of motor neurons (MNs) in the motor cortex, brainstem, and spinal cord, resulting in death of patients 2-5 years after diagnosis. Glutamate-mediated excitotoxicity in the CNS has been implicated as a major contributor to the manifestation of ALS. It is thought that glutamate-mediated excitotoxicity in ALS is due to diminished capacity of motor neurons to handle excessive Ca2+ influx, which serves as a trigger for neurodegeneration. Therefore, the development of drugs which lower Ca2+ influx associated with excitatory activity in CNS is widely considered as an important focal point in the search for therapeutics for ALS. Ionotropic AMPA receptors are glutamate-activated ion channels that are key regulators of Ca2+ influx and the excitatory state of the CNS. We propose to develop novel steric block nucleic acid agents called antisense oligomers (AOs) that will lead to the production of more desensitizable AMPA receptors. AMPA receptors are pentamers composed of 4 subunits termed GluR1-4, present in various homomeric and heteromeric combinations. Two alternatively spliced variants of all GluRs called "flip" and "flop" are normally expressed in the CNS. The AMPA "flip" variants are more resistant to desentization, whereas the "flop" variants are readily desensitized. Thus, when the flip/flop ratio of GluR1, GluR3 and GluR4 is elevated, the AMPA receptors are resistant to desensitization, and neurons are more excitable and permit greater influx of calcium. In this proposal, we will develop novel AOs that function to specifically lower GluR flip isoform expression, and thus decrease flip/flop ratio. We will evaluate AO efficacy in vitro, including assessment of their functional affects on AMPA currents and also test their efficacy in normal mice after intracerebroventricular (ICV) delivery. We propose that the optimized AOs could lead to a novel therapeutic strategy to treat ALS by increasing GluR subunit-specific AMPA desentization, resulting in neuroprotection. Also, there is evidence that the number of Ca2+-permeable AMPA receptors and the flip/flop ratio may be abnormally high in ALS, further supporting our rationale to develop compounds that increase AMPA channel desensitization. Also, our AOs may be applicable to other disorders where modulating AMPA receptor activity is a focus of current drug discovery, including epilepsy, Parkinsonism, traumatic brain injury, neuropathic pain, and stroke. PUBLIC HEALTH RELEVANCE: We propose to develop and validate compounds called steric block oligomers in pre-clincal studies that could ultimately lead to a novel therapeutic strategy to treat Amyotrophic lateral sclerosis (ALS) in humans, by normalizing synaptic function in spinal motor neurons.

描述（由申请人提供）：肌萎缩性侧索硬化症（ALS）的特征在于运动皮层、脑干和脊髓中运动神经元（MN）的进行性和选择性丧失，导致患者在诊断后2-5年死亡。CNS中谷氨酸介导的兴奋性毒性已被认为是ALS表现的主要贡献者。据认为，ALS中谷氨酸介导的兴奋性毒性是由于运动神经元处理过量Ca 2+内流的能力降低，这是神经变性的触发因素。因此，开发降低CNS中与兴奋性活性相关的Ca 2+内流的药物被广泛认为是ALS治疗剂研究的重要焦点。离子型AMPA受体是谷氨酸激活的离子通道，是Ca 2+内流和CNS兴奋状态的关键调节剂。我们建议开发新的空间位阻核酸试剂称为反义寡聚物（AO），这将导致生产更多的脱敏AMPA受体。AMPA受体是由称为GluR 1 -4的4个亚基组成的五聚体，以各种同源和异源组合存在。所有GluR的两种选择性剪接变体称为“翻转”和“翻转”，通常在中枢神经系统中表达。AMPA“翻转”变体对脱敏更有抵抗力，而“翻转”变体很容易脱敏。因此，当GluR 1、GluR 3和GluR 4的翻转/翻转比率升高时，AMPA受体对脱敏有抵抗力，神经元更易兴奋并允许更多的钙流入。在这个提议中，我们将开发新的AO，其功能是特异性降低GluR翻转亚型表达，从而降低翻转/翻转率。我们将在体外评估AO的疗效，包括评估其对AMPA电流的功能影响，并在脑室内（ICV）给药后在正常小鼠中测试其疗效。我们建议，优化的AO可能会导致一种新的治疗策略，通过增加GluR亚基特异性AMPA desentization，导致神经保护治疗ALS。此外，有证据表明，钙渗透AMPA受体的数量和翻转/翻转比可能在ALS中异常高，进一步支持我们开发增加AMPA通道脱敏的化合物的理论基础。此外，我们的AO可能适用于其他疾病，其中调节AMPA受体活性是当前药物发现的焦点，包括癫痫，帕金森症，创伤性脑损伤，神经性疼痛和中风。 公共卫生相关性：我们建议在临床前研究中开发和验证称为空间阻断低聚物的化合物，这可能最终导致一种新的治疗策略，通过使脊髓运动神经元的突触功能正常化来治疗人类肌萎缩性侧索硬化症（ALS）。