Molecular Therapies to Promote White Matter Restoration After Traumatic Brain Injury

分子疗法促进脑外伤后白质恢复

• 批准号: 9773237
• 负责人: MICHAEL V L BENNETT
• 金额: $ 38.66万
• 依托单位: UNIVERSITY OF PITTSBURGH AT PITTSBURGH
• 依托单位国家: 美国
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-09-30 至 2023-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9773237
• 关键词: Action Potentials; Acute; Alteplase; Amino Acid Substitution; Amino Acids; Anti-Inflammatory Agents; Antioxidants; Axon; Behavioral; Binding; Blood - brain barrier anatomy; Brain; Brain Edema; Cause of Death; Cell Differentiation process; Cell Maturation; Cerebral hemisphere hemorrhage; Clinic; Clinical; Coculture Techniques; Cognitive deficits; Data; Demyelinations; Dose; Electrophysiology (science); Epidermal Growth Factor Receptor; Exhibits; FDA approved; Failure; Fiber; Fostering; Generations; Genes; Human; Impairment; Injury; Intervention; Intranasal Administration; Ischemic Stroke; Knock-out; Knockout Mice; Mediating; Membrane; Modeling; Molecular; Mus; Myelin; Myelin Sheath; Nervous System Physiology; Neuraxis; Neurites; Neurological outcome; Neurons; Nuclear Receptors; Oligodendroglia; Outcome; PPAR alpha; PPAR gamma; Peptide Hydrolases; Peroxisome Proliferator-Activated Receptors; Plasminogen Activator; Play; Prevention therapy; Process; Proliferating; Property; Recovery; Recovery of Function; Reporting; Reproducibility; Research; Risk; Role; Serine Protease; Signal Transduction; Structure; System; TBI treatment; Testing; Therapeutic Agents; Time; Traumatic Brain Injury; Traumatic Brain Injury recovery; axon regeneration; axonal degeneration; axonal sprouting; base; conditional knockout; controlled cortical impact; deprivation; disability; functional improvement; gray matter; improved; in vivo; knock-down; mouse model; mutant; myelination; nanomolar; neglect; neurological recovery; neurorestoration; novel; oligodendrocyte precursor; overexpression; pre-clinical; precursor cell; public health relevance; receptor; remyelination; repaired; restoration; thrombolysis; transcription factor; white matter; white matter injury; young adult

 DESCRIPTION (provided by applicant): White matter (WM) injury, which is characterized by axonal degeneration and loss of the myelin sheath (demyelination), is important for the long-term functional deficits after traumatic brain injury (TBI). The central nervous system exhibits limited capacity for WM repair, such as axonal regeneration and remyelination. During post-TBI WM repair, oligodendrocyte precursor cells (OPCs) are known to actively proliferate. However, many newly generated OPCs fail to differentiate into mature, myelin- This application will examine the effect of intranasal delivery of protease inactive plasminogen activator mutant (tPAm) to enhance differentiation and maturation of oligodendyocytes to promote white matter integrity following TBI. producing oligodendrocytes (OLs), resulting in inadequate remyelination. Failed remyelination not only diminishes signal transduction, but also leads to axon degeneration and worsens clinical outcome. Thus, interventions that promote OPC differentiation and maturation are promising strategies to enhance WM repair and improve functional recovery. Recombinant tissue plasminogen activator (tPA) is an FDA-approved treatment for ischemic stroke and catalyzes thrombolysis through serine protease action. Recent studies have discovered direct neurorestorative effects of tPA independent of protease activities. However, the clinical use of tPA as a therapeutic agent in TBI raises several concerns, as it can also cause blood-brain barrier damage and brain edema. In this proposal, we will explore protease-inactive mutant tPA (tPAm), with substitution of a single amino acid (S478A) to eliminate protease action, as a novel restorative therapy to promote remyelination and WM repair after TBI. We discovered that nanomolar concentrations of tPAm promote the differentiation of cultured primary OPCs into mature OLs. In addition, tPA knockout exacerbates behavioral deficits and WM injury lasting at least 35 days after TBI whereas post-injury intranasal administration of tPAm improves long-term neurological function and WM integrity after TBI in mice. Pilot data further suggest that tPAm enhances WM repair after TBI by promoting OPC differentiation and axon remyelination and that the effect may be mediated by the peroxisome proliferator-activated receptor γ (PPARγ) nuclear receptor. Here we will focus on the novel remyelinating actions of tPAm and test the following hypothesis: Treatment with protease inactive tPAm facilitates WM repair and long-term neurological recovery after TBI, at least in part, by inducing OPC differentiation and axonal myelination through PPARγ activation. Three Specific Aims will be tested. Aim 1: Determine whether post-TBI treatment with tPAm enhances WM integrity and promotes long-term recovery. Aim 2: Test the hypothesis that tPAm induces OPC differentiation/maturation and promotes axonal myelination through PPAR activation. Aim 3: Test the hypothesis that tPAm-induced OPC differentiation and axonal myelination are essential for the protection of WM integrity and long-term recovery after TBI. These studies are the first to investigate the potential for tPAm to foster remyelination in TBI an will identify the underlying mechanism of action, thereby setting the stage for the potential use o tPAm in the clinic.

 描述(申请人提供)：白质(WM)损伤，其特征是轴突变性和髓鞘丢失(脱髓鞘)，是创伤性脑损伤(TBI)后长期功能障碍的重要因素。中枢神经系统对WM的修复能力有限，如轴突再生和重新髓鞘形成。在脑外伤后的WM修复过程中，少突胶质前体细胞(OPC)被认为是活跃的增殖。然而，许多新生成的OPC无法分化为成熟的髓鞘细胞-本应用将检测鼻内注射蛋白酶失活的纤溶酶原激活剂突变体(TPAm)促进少突胶质细胞分化和成熟的作用，以促进脑损伤后白质的完整性。产生少突胶质细胞(OLs)，导致髓鞘再生不足。髓鞘再生失败不仅会减少信号转导，还会导致轴突变性，恶化临床预后。因此，促进OPC分化和成熟的干预措施是促进WM修复和改善功能恢复的有前景的策略。重组组织型纤溶酶原激活剂(TPA)是FDA批准的治疗缺血性卒中的药物，通过丝氨酸蛋白酶作用催化溶栓。最近的研究发现，tPA的直接神经修复作用不依赖于蛋白水解酶活性。然而，tPA作为脑外伤的治疗剂的临床应用引起了几个问题，因为它也会导致血脑屏障损伤和脑水肿。在这项建议中，我们将探索用单一氨基酸(S478A)取代蛋白酶失活突变体tPA(TPAm)来消除蛋白酶作用，作为一种新的恢复疗法来促进脑外伤后的髓鞘再生和WM修复。我们发现，纳米分子浓度的tPAm促进培养的原代OPC分化为成熟的OPC。此外，tPA基因敲除会加剧小鼠的行为缺陷和持续至少35天的西医损伤，而损伤后鼻腔注射tPAm可以改善小鼠脑损伤后的长期神经功能和西医知识的完整性。实验数据进一步表明，tPAm通过促进OPC分化和轴突再髓鞘形成，促进脑外伤后的WM修复，其作用可能是通过过氧化物酶体增殖物激活受体γ(PPARγ)核受体介导的。在这里，我们将重点研究tPAm的新的再髓鞘作用，并检验以下假设：用失活的tPAm治疗促进脑挫伤后的WM修复和长期的神经恢复，至少部分是通过激活PPARγ诱导OPC分化和轴突髓鞘形成。将测试三个具体目标。目的1：确定创伤性脑损伤后应用组织型纤溶酶原激活剂(TPAm)治疗是否增强了西医的完整性并促进了长期康复。目的：验证tPAm通过激活PPAR诱导OPC分化成熟并促进轴突髓鞘形成的假说。目的：验证组织型纤溶酶原激活剂(TPAm)诱导的OPC分化和轴突髓鞘形成对脑外伤后WM的完整性和长期恢复至关重要的假说。这些研究首次探讨了tPAm促进脑外伤后再髓鞘形成的可能性，并将确定其潜在的作用机制，从而为tPAm在临床上的潜在应用奠定基础。