Supplement: L-selectin shedding as a novel therapeutic strategy to mitigate acute secondary damage after spinal cord injury

补充：L-选择素脱落作为减轻脊髓损伤后急性继发性损伤的新治疗策略

• 批准号: 10789000
• 负责人: Dylan A. McCreedy
• 金额: $ 2.58万
• 依托单位: TEXAS A&M UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-08-01 至 2025-06-30
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10789000
• 关键词: Acute; Adhesions; Affect; Antibodies; Attenuated; Behavior; Binding; Blood; Cells; Chemosensitization; Clinical; Contusions; Diclofenac; Disease; Environment; Event; Excision; Exposure to; FDA approved; Goals; Hour; Human; Immune; In Vitro; Individual; Infection; Inflammation; Inflammatory; Injury; Intravenous; Invaded; Knock-in Mouse; L Forms; L-Selectin; Ligand Binding; Ligands; Mediating; Mediator; Modeling; Mus; Myelin; Neurologic Deficit; Neurological outcome; Neutrophil Activation; Non-Steroidal Anti-Inflammatory Agents; Pathogenicity; Patients; Phase; Play; Process; Production; Quality of life; Reactive Oxygen Species; Receptor Signaling; Recovery; Recovery of Function; Recruitment Activity; Rehabilitation therapy; Research; Role; Spinal Cord; Spinal cord injury; Surface; Testing; Therapeutic; Therapeutic Effect; Tissues; Work; adhesion receptor; cell type; central nervous system injury; clinically relevant; cytotoxic; effective therapy; improved; in vitro activity; in vivo; intraperitoneal; intravenous administration; intravenous injection; long term recovery; neurological recovery; neuroprotection; neutrophil; new therapeutic target; novel therapeutic intervention; receptor; recruit; response; response to injury; spinal cord white matter; therapeutic target; white matter

Project Summary/Abstract Inflammation plays a critical role in secondary tissue damage after spinal cord injury (SCI), however, there is no widely accepted therapeutic for mitigating destructive inflammatory events in the injured spinal cord. L-selectin is an adhesion and signaling receptor on immune cells that has been recently shown to be a critical mediator of long-term neurological deficits following SCI. Disrupting L-selectin function with diclofenac, an FDA-approved non-steroidal anti-inflammatory drug (NSAID) that induces L-selectin “shedding”, improves tissue sparing and long-term recovery when administered by 3 hours post-SCI. L-selectin shedding, therefore, represents a potential therapeutic strategy to mitigate damage associated with acute inflammation. However, the specific mechanisms through which L-selectin attenuates secondary tissue damage remain unclear. L-selectin has been shown to promote destructive effector functions in neutrophils, the most abundant immune cell type in human blood and first to invade the injured spinal cord in large numbers. The hypothesis of this proposal is that L- selectin shedding reduces the pathogenic activities of neutrophils and associated secondary tissue damage after SCI. The objectives of this work are to determine the effect of L-selectin shedding on the activation of neutrophil effector functions, further elucidate the role of neutrophils in secondary tissue damage after SCI, and determine if intravenous delivery extends the therapeutic window for diclofenac. Specific Aim 1 will test the hypothesis that L-selectin shedding reduces the activation of cytotoxic neutrophil effector functions in the presence of myelin. Myelin can serve as an abundant ligand for L-selectin and may exacerbate cytotoxic effector functions in neutrophils. Using mice that cannot shed L-selectin (L(E) mice) and WT mice treated with diclofenac, the effect of L-selectin shedding on neutrophil effector functions will be quantified in vitro in response to myelin exposure as well as in the acutely injured spinal cord. Specific Aim 2 will test the hypothesis that neutrophils are the primary immune cell type whose destructive functions are mitigated by L-selectin shedding. Early neutrophil depletion will be investigated in L(E) mice and in WT mice treated with diclofenac to determine the extent to which L-selectin shedding reduces secondary damage and neurological deficits by attenuating pathogenic neutrophil activities. Specific Aim 3 will test the hypothesis that intravenous delivery of diclofenac can induce rapid shedding of L-selectin on neutrophils in the blood and extend the window of opportunity. Long-term neurological recovery and tissue sparing will be assessed following delayed intravenous administration of diclofenac in WT mice. Diclofenac treatment will also be assessed in L(E) mice to confirm that the therapeutic mechanisms of action is through L-selectin shedding. The collective results will help uncover the roles of L- selectin shedding and neutrophils in secondary damage after SCI and validate L-selectin shedding as a therapeutic target to improve long-term neurological recovery. The findings from this proposal will also be applicable to attenuating damaging inflammation observed in other central nervous system injuries or disorders.

项目摘要/摘要 炎症在脊髓损伤（SCI）后次要组织损伤（SCI）中起关键作用，但是，没有 广泛接受的理论可缓解受伤的脊髓破坏性炎症事件。 L-选择素 是免疫细胞上的粘附和信号受体，最近已被证明是 科学后的长期神经防御措施。用双氯芬酸（FDA批准）破坏L-选择蛋白功能 非甾体类抗炎药（NSAID）影响L-选择蛋白“脱落”，改善组织较高和 SCI后3小时施用长期恢复。因此，l-选择蛋白脱落代表 潜在的治疗策略，以减轻与急性炎症有关的损害。但是，具体 L-选择素减弱次级组织损伤的机制尚不清楚。 L-选择蛋白已经存在 证明可以促进中性粒细胞中的破坏性效应子功能，这是人类最丰富的免疫细胞类型 血液，首先大量入侵受伤的脊髓。该提议的假设是l- Selectin脱落会降低中性粒细胞和相关次要组织的致病活性 科幻后的损坏。这项工作的目的是确定L-选择素脱落对激活的影响 中性粒细胞效应子的功能，进一步阐明了中性粒细胞在SCI后次生组织损伤中的作用， 并确定静脉输送是否扩展了双氯芬酸的治疗窗口。特定目标1将测试 假设L-选择素脱落会降低细胞毒性中性粒细胞效应子功能的激活 髓磷脂可以作为L-选择素的绝对配体，并且可能加剧细胞毒性效应子 中性粒细胞的功能。使用无法脱落L-选择素（L（E）小鼠）和用双氯芬酸治疗的WT小鼠的小鼠， L-选择素脱落对中性粒细胞效应子功能的影响将在体外对髓磷脂进行定量 暴露以及急性损伤的脊髓。具体目标2将检验中性粒细胞是 L-选择蛋白脱落来减轻破坏性功能的主要免疫细胞类型。早期中性粒细胞 将在L（E）小鼠和用双氯芬酸治疗的WT小鼠中研究耗竭，以确定 L-选择素脱落通过减弱致病性可减少次要损伤和神经系统缺陷 中性粒细胞活动。具体目标3将检验以下假设：双氯芬酸的静脉输送可以诱导 L-选择素在血液中的中性粒细胞上快速脱落，并扩展机会窗口。长期 在延迟静脉注射后，将评估神经系统恢复和组织的保留 WT小鼠的双氯芬酸。双氯芬酸治疗也将在L（e）小鼠中进行评估，以确认该治疗 作用机理是通过L-选择蛋白脱落的。集体结果将有助于发现L-的作用 Selectin脱落和嗜中性粒细胞在SCI之后造成次要损伤，并验证L-选择蛋白脱落作为一个 改善长期神经恢复的治疗靶标。该提议的发现也将是 适用于在其他中枢神经系统损伤或疾病中观察到的损害感染。