Role of ryanodine receptor dysfunction after spinal cord injury

兰尼碱受体功能障碍在脊髓损伤后的作用

• 批准号: 9751868
• 负责人: Helen M Bramlett
• 金额: --
• 依托单位: JAMES J PETERS VA MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-10-01 至 2021-09-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9751868
• 关键词: Affect; Aging; American; Animal Model; Area; Atrophic; Behavioral; Binding; Calcium; Collaborations; Contusions; Coupling; Data; Deterioration; Disseminated Malignant Neoplasm; Dissociation; Drug usage; Fatigue; Fiber; Force of Gravity; Functional disorder; Gait; Hand; Hindlimb; Impairment; Individual; Injury; Intervention; Knock-out; Knowledge; Lead; Lesion; Link; Locomotion; Longevity; Modeling; Motor; Motor Neurons; Mus; Muscle; Muscle Contraction; Muscle Weakness; Muscle function; NADH oxidase; Outcome; Oxides; Paralysed; Pharmaceutical Preparations; Pharmacologic Substance; Pharmacology; Physiological; Production; Quality of Care; Quality of life; Reactive Oxygen Species; Recovery of Function; Rehabilitation therapy; Research Personnel; Resistance; Role; Ryanodine Receptor Calcium Release Channel; Ryanodine Receptors; Sarcoplasmic Reticulum; Skeletal Muscle; Source; Spinal Cord; Spinal Cord Contusions; Spinal Cord transection injury; Spinal cord injury; Testing; Thoracic spinal cord structure; Time; Ursidae Family; Veterans; Weight; Work; arm; disability; effective therapy; experience; experimental study; gait examination; improved; improved functioning; inhibitor/antagonist; muscle strength; neuromuscular function; novel; oxidation; prevent; response; small molecule; treatment effect

Muscles paralyzed by spinal cord injury (SCI) atrophy extensively, are weaker, fatigue more quickly and generate lower specific tension (force produced per unit of cross-sectional area), such that they generate less force in response to maximal motor neuron activation. For individuals with motor-incomplete lesions, interventions that improve specific force and/or fatigue resistance would be obvious opportunities to improve function. A newly recognized cause of impaired specific force production is oxidation/nitrosylation of ryanodine receptors (RyR) which results in dissociation of calstabin and spontaneous opening of RyR thereby impairing RyR gating; the ultimate physiological effect of RyR dysfunction is diminished force of muscle contraction and lower muscle endurance. Small molecules such as S107 bind oxidized/nitrosylated RyR and improve specific force by as much as 50%. Our preliminary data demonstrates extensive oxidation/nitrosylation of RyR in muscle after SCI thus implicating RyR dysfunction in reduced specific force production and endurance of paralyzed muscle after SCI. These changes in RyR are associated with increased expression of NADH oxidase 4 (Nox4) which is a potent source of reactive oxygen species (ROS) that has been linked to RyR. A direct link between Nox4 and oxidation/nitrosylation of RyR is supported by findings that binding of Nox4 to RyR is also increased in muscle after SCI. The overarching objectives of this application are to test the possibility that administration of S107 or a Nox4 inhibitor after SCI will improve skeletal muscle specific tension and endurance, and hence function, and to investigate the role of Nox4 in oxidation/nitrosylation of RyR in skeletal muscle after SCI. Aim 1. To determine the role of elevated Nox4 expression in the oxidation/nitrosylation of RyR in muscle after spinal cord transection. Hypothesis: oxidation/nitrosylation of RyR after SCI results from increased expression and activity of Nox4. Approach. Aim 1A. We will compare SCI and sham-operated groups over time after a spinal cord transection at various times between 1 and 56 days after SCI. We will examine the temporal relationships between oxidation/nitrosylation of RyR and dissociation of calstabin from RyR with changes in Nox4 expression. Aim 1B: Effects of a conditional knockout of Nox4 in skeletal muscle on muscle strength, specific force, fatigue, RyR oxidation after SCI will be determined. Aim 1C: We will compare muscle force production, specific force, fatigue, RyR oxidation/nitrosylation and binding of RyR to calstabin between spinal cord transected mice treated with a Nox4 inhibitor or vehicle. Aim 2) To test the effects of S107 on muscle force production and RyR-calstabin binding interactions after spinal cord transection. Hypothesis: administration of S107 will improve muscle specific force and endurance and increase calstabin binding to RyR but will not alter RyR oxidation/nitrosylation. Approach: We will compare muscle specific force, endurance, binding of calstabin to RyR, and RyR oxidation/nitrosylation between SCI groups administered S107 or vehicle. Aim 3. To A) determine whether S107 or a Nox4 inhibitor improves functional recovery after a contusion SCI. Hypothesis: S107 or a Nox4 inhibitor improves functional recovery in a graded contusion model of mid-thoracic SCI in mice. Approach: Following a mild, moderate or severe contusion spinal cord injury, mice will be treated with the most effective drug (either S107 or GKT137831) from Aims 1 and 2 or vehicle. Effects of the treatment on locomotor function and gait will be determined. Expected Outcomes and Benefits to Veterans. Knowledge gained from such studies may result in new pharmacologic or rehabilitation treatments to improve function after SCI.

脊髓损伤瘫痪（SCI）萎缩的肌肉广泛弱，疲劳更快，并且 产生较低的特异性张力（每单位横截面区域产生的力），以使它们产生 对最大运动神经元激活的响应力较小。对于患有运动损伤的个体， 改善特定力和/或抗疲劳抗性的干预措施将是改善的明显机会 功能。特异性产生受损的新认识的原因是氧化/亚硝基化的 Ryanodine受体（RYR），导致calstabin的解离和RYR的自发开放 从而损害了里尔的门； RYR功能障碍的最终生理效应是减弱的力量 肌肉收缩和降低肌肉耐力。小分子（例如S107）结合氧化/亚硝基化的 RYR并将特定力提高多达50％。我们的初步数据证明了广泛的 SCI后，RYR在肌肉中的氧化/亚硝基化，从而暗示了RYR功能障碍在降低的特定力中 SCI后瘫痪的肌肉的产生和耐力。 RYR中的这些变化与 NADH氧化酶4（NOX4）的表达增加，这是活性氧的有效来源 （ROS）与RYR相关。 NOX4与RYR的氧化/亚硝基化之间的直接联系 在SCI后肌肉中NOX4与RYR结合的发现也增加了。总体 此应用程序的目标是测试S107或NOX4抑制剂后的可能性 SCI将改善骨骼肌特异性张力和耐力，从而发挥作用，并研究 SCI后，NOX4在RYR中RYR的氧化/硝基化中的作用。 目的1。确定升高NOX4表达在RYR中的氧化/亚硝基化中的作用 脊髓横切后的肌肉。假设：SCI后RYR的氧化/亚硝基化。 NOX4的表达和活性增加。方法。目标1a。我们将比较SCI和假手术 在SCI后1至56天之间的不同时间进行脊髓横断后的小组。我们将 检查RYR的氧化/亚硝基化与Calstabin解离之间的时间关系 来自RYR，随着NOX4表达的变化。 AIM 1B：骨骼中有条件敲除NOX4的效果 将确定肌肉力量，特定力，疲劳，SCI后的RYR氧化。 AIM 1C：我们 将比较肌肉力量的产生，特定力，疲劳，RYR氧化/亚硝基化和RYR的结合 在用NOX4抑制剂或媒介物处理的脊髓转移小鼠之间进行calstabin。 目标2）测试S107对肌肉力量产生和RYR-Calstabin结合的影响 脊髓横断后的相互作用。假设：施用S107将改善肌肉 特定的力和耐力并增加calstabin与RYR的结合，但不会改变RYR 氧化/亚硝基化。方法：我们将比较肌肉特定力，耐力，calstabin与 RYR和RYR氧化/硝基化的SCI组之间的​​S107或媒介物。 目标3。a）确定S107或NOX4抑制剂是否改善了功能恢复 挫伤科学。假设：S107或NOX4抑制剂可改善分级挫伤的功能恢复 小鼠中胸腔SCI的模型。方法：轻度，中度或重度脊髓之后 损伤，将用目标1和2或2或 车辆。将确定治疗对运动功能和步态的影响。 对退伍军人的预期成果和利益。从这些研究中获得的知识可能会导致 新的药理学或康复治疗可改善SCI后功能。