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

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

基本信息

批准号：
10456186
负责人：
Dylan A. McCreedy
金额：
$ 36.75万
依托单位：
TEXAS A&M UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2021
资助国家：
美国
起止时间：
2021-08-01 至 2026-06-30
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10456186
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 of activation protein 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 Contusions 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 neurological recovery neuroprotection neutrophil new therapeutic target novel therapeutic intervention receptor recruit response response to injury spinal cord white matter therapeutic target white matter

项目摘要

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.

项目概要/摘要炎症在脊髓损伤（SCI）后的继发性组织损伤中起着至关重要的作用，然而，目前还没有广泛接受的用于减轻受损脊髓中破坏性炎症事件的疗法。是免疫细胞上的一种粘附和信号传导受体，最近被证明是免疫细胞的关键介质使用双氯芬酸（FDA 批准的一种药物）破坏 SCI 后的长期神经功能缺损。非甾体抗炎药 (NSAID) 可诱导 L-选择素“脱落”，改善组织保护并因此，SCI 后 3 小时 L-选择素脱落后即可实现长期恢复。然而，减轻急性炎症相关损害的潜在治疗策略。 L-选择素减轻继发性组织损伤的机制尚不清楚。显示可促进中性粒细胞的破坏性效应功能，中性粒细胞是人类最丰富的免疫细胞类型该提议的假设是L-。选择素脱落降低中性粒细胞和相关次级组织的致病活性这项工作的目的是确定 L-选择素脱落对激活的影响。中性粒细胞效应功能的研究，进一步阐明中性粒细胞在 SCI 后继发性组织损伤中的作用，并确定静脉注射是否延长了双氯芬酸的治疗窗。具体目标 1 将测试 L-选择素脱落会减少细胞毒性中性粒细胞效应功能的激活髓磷脂的存在可以作为 L-选择素的丰富配体，并可能加剧细胞毒性效应。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功能的影响将在体外根据髓磷脂进行量化特定目标 2 将检验中性粒细胞存在的假设。早期中性粒细胞脱落可减轻其破坏性功能的主要免疫细胞类型。将在 L(E) 小鼠和用双氯芬酸治疗的 WT 小鼠中研究消耗，以确定消耗的程度 L-选择素脱落继发性通过减弱致病性来减少损伤和神经功能缺损具体目标 3 将检验静脉注射双氯芬酸可诱导中性粒细胞活性的假设。血液中中性粒细胞上的 L-选择素快速脱落并延长长期机会窗口。延迟静脉注射后将评估神经恢复和组织保留还将在 L(E) 小鼠中评估双氯芬酸治疗，以确认治疗效果。作用机制是通过 L-选择素脱落。集体结果将有助于揭示 L-选择素的作用。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-选择素脱落作为该提案的研究结果也将是改善长期神经治疗恢复的目标。适用于减轻在其他中枢神经系统损伤或疾病中观察到的破坏性炎症。