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.

项目总结/摘要 炎症在脊髓损伤（SCI）后继发性组织损伤中起着关键作用，然而， 被广泛接受的用于减轻受损脊髓中的破坏性炎症事件的治疗剂。L-selectin 是免疫细胞上的粘附和信号受体，最近已被证明是免疫细胞粘附的关键介质。 脊髓损伤后的长期神经功能缺损。FDA批准的双氯芬酸破坏L-选择素功能 非甾体抗炎药（NSAID），诱导L-选择素“脱落”，改善组织保护， SCI后3小时给药时的长期恢复。因此，L-选择素脱落代表了 潜在的治疗策略，以减轻与急性炎症相关的损害。但具体 L-选择素减弱继发性组织损伤的机制仍不清楚。L-选择素已经被 显示促进中性粒细胞中的破坏性效应子功能，中性粒细胞是人类中最丰富的免疫细胞类型 血液首先大量侵入受损的脊髓。该建议的假设是，L- 选择素脱落降低了中性粒细胞和相关次级组织的致病活性 SCI后的损伤这项工作的目的是确定L-选择素脱落对激活的影响， 中性粒细胞效应器功能，进一步阐明中性粒细胞在SCI后继发性组织损伤中的作用， 并确定静脉给药是否延长了双氯芬酸的治疗窗口。具体目标1将测试 假设L-选择素脱落减少了细胞毒性中性粒细胞效应子功能的激活， 髓鞘的存在。髓磷脂可作为L-选择素的丰富配体，并可加重细胞毒性效应 在中性粒细胞中起作用。使用不能脱落L-选择素的小鼠（L（E）小鼠）和用双氯芬酸处理的WT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响应髓磷脂 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 其破坏性功能被L-选择素脱落减轻的主要免疫细胞类型。早期中性粒细胞 将在L（E）小鼠和用双氯芬酸处理的WT小鼠中研究消耗，以确定 该L-选择素脱落通过减弱致病性神经损伤和神经功能缺损， 中性粒细胞活性具体目标3将检验双氯芬酸静脉给药可诱导 血液中中性粒细胞上的L-选择素快速脱落，并延长机会窗口。长期 神经恢复和组织保留将在延迟静脉内施用 WT小鼠中的双氯芬酸。还将在L（E）小鼠中评估双氯芬酸治疗，以确认治疗性 作用机制是通过L-选择素脱落。集体的结果将有助于揭示L- 选择素脱落和中性粒细胞在SCI后继发性损伤中的作用，并验证L-选择素脱落作为一种 治疗目标，以改善长期的神经恢复。这项建议的结果也将是 适用于减轻在其它中枢神经系统损伤或病症中观察到的损伤性炎症。