White matter restoration and functional recovery after experimental stroke

实验性卒中后白质恢复和功能恢复

• 批准号: 9054320
• 负责人: Jun Chen
• 金额: $ 33.69万
• 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: 2015-09-15 至 2020-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9054320
• 关键词: Action Potentials; Acute; Adult; Alteplase; Amino Acid Substitution; Anti-Inflammatory Agents; Anti-inflammatory; Antioxidants; Axon; Behavior; Binding; Blood - brain barrier anatomy; Brain; Cell Differentiation process; Cerebral Ischemia; Cerebral hemisphere hemorrhage; Clinical; Coculture Techniques; Cognitive deficits; Corpus Callosum; Data; Demyelinations; Distal; Dose; Epidermal Growth Factor Receptor; External Capsule; FDA approved; Failure; Fibrinolytic Agents; Generations; Genes; Human; Infarction; Injury; Intervention; Intranasal Administration; Intraventricular Infusion; Ischemic Stroke; Knockout Mice; Lead; Mediating; Membrane; Middle Cerebral Artery Occlusion; Modeling; Mus; Myelin; Myelin Sheath; Myelinated nerve fiber; Nervous System Physiology; Neurites; Neurologic; Neurological outcome; Neurons; Oligodendroglia; Patients; Peptide Hydrolases; Peroxisome Proliferator-Activated Receptors; Play; Prevention therapy; Process; Recovery; Recovery of Function; Regenerative response; Research; Risk; Rodent Model; Role; Serine Protease; Stroke; System; Testing; Therapeutic; Time; aged; axonal sprouting; cognitive testing; deprivation; disability; improved; in vivo; injured; mutant; myelination; neurological recovery; neurorestoration; neurotransmission; novel; oligodendrocyte precursor; overexpression; post stroke; precursor cell; public health relevance; receptor; remyelination; repaired; restoration; stroke therapy; thrombolysis; white matter; white matter injury; young adult

 DESCRIPTION (provided by applicant): White matter (WM) injury, characterized by demyelination and loss of axonal integrity, is an important cause of long-term sensorimotor and cognitive deficits after stroke. WM repair, including axonal regrowth, oligodendrogenesis and the myelination of demyelinated or newly generated axons, would help rebuild neuronal connectivity and reestablish axonal signal conduction. Unfortunately, the adult brain has limited capacity for remyelination, at least in part due to the failure of differentiation of oligodendrocyte precursor cells (OPCs) into mature, myelinating oligodendrocytes (OLs). Thus, interventions that promote OPC differentiation may facilitate axonal remyelination, WM repair and long-term neurological recovery in stroke patients. Human recombinant tissue plasminogen activator (tPA) is the only FDA approved drug for the thrombolytic treatment of ischemic stroke. However, recent research has discovered various neuroprotective effects by tPA that are independent of its thrombolytic activity. Moreover, intranasal administration of tPA improves functional recovery and promotes axonal sprouting after stroke. Currently, the use of tPA is limited to the first 4.5 hr after the oset of stroke, as beyond this time window it tremendously increases the risk of intracerebral hemorrhage (ICH) via BBB damage. This proposal will investigate the efficacy of tPAm, a mutant form of tPA that lacks thrombolytic activity (thus would not induce ICH), in rodent models of ischemic stroke. We have found in primary cultures that tPAm potently promotes the differentiation of OPCs into mature OLs. This effect of tPAm depends on its activation of PPAR, a master transcriptional factor that regulates cell differentiation and possesses antioxidant and anti-inflammatory functions. In vivo studies suggest that lack of endogenous tPA exacerbates functional deficits and WM injury up to 35 days after distal MCAO. In contrast, tPAm administration 6 hr after transient MCAO improved long-term neurological behavior and WM integrity. Our results suggest that tPAm enhances post-stroke WM integrity, at least in part, by promoting OPC differentiation and axonal myelination. This proposal will investigate the novel WM repair-enhancing role of tPAm and the underlying mechanisms. We will test the following overarching hypothesis: Treatment with protease-inactive tPAm facilitates WM repair and long-term neurological recovery after stroke, at least in part by promoting OPC differentiation and axonal myelination through PPAR. Both young adult and aged mice will be tested. Three Specific Aims are proposed. Aim 1: Determine whether post-stroke treatment with the protease-inactive tPAm enhances WM integrity and promotes long-term neurological recovery. Aim 2: Test the hypothesis that tPAm induces OPC differentiation/maturation and promotes axonal myelination via PPAR activation. Primary OPCs and a neuron-OPC co-culture system will be applied to test this hypothesis. Aim 3: Test the hypothesis that tPAm-induced OPC differentiation and axonal myelination/remyelination are essential for its beneficial effects on WM integrity and long-term neurological recovery after stroke.

 描述（由适用提供）：以脱髓鞘和轴突完整性丧失为特征的白质（WM）损伤是中风后长期感觉运动和认知缺陷的重要原因。 WM修复，包括轴突改革，少突胶质发生以及脱髓鞘或新产生的轴突的髓鞘形成，将有助于重建神经元连通性并重建轴突信号传导。不幸的是，成年大脑的再生能力有限，至少部分是由于少突胶质细胞前体细胞（OPC）分化为成熟的成熟的，髓鞘的少突胶质细胞（OLS）的失败。这是促进OPC分化的干预措施可以促进中风患者的轴突再髓质，WM修复和长期神经恢复。人类重组组织纤溶酶原激活剂（TPA）是唯一获得缺血性中风溶栓治疗的FDA批准药物。但是，最近的研究发现了TPA的各种神经保护作用，这些作用与其溶栓活性无关。此外，TPA的鼻内给药可改善功能恢复，并促进中风后轴突摆动。当前，TPA的使用仅限于中风osset后的前4.5小时，因为除了这个时间窗口之外，它会通过BBB损害极大地增加脑内出血（ICH）的风险。该建议将研究TPAM的有效性，TPAM是缺血性中风模型中缺乏溶栓活性的TPA突变形式（因此不会诱导ICH）。我们在原发性培养物中发现TPAM可能会促进OPC分化为成熟OLS。 TPAM的这种影响取决于其PPAR的激活，PPAR是一种调节细胞分化并具有抗氧化剂和抗炎功能的主转录因子。体内研究表明，缺乏内源性TPA加剧功能性缺陷和WM损伤，直到远端MCAO后35天。相反，瞬时MCAO后6小时的TPAM给药改善了长期神经行为和WM完整性。我们的结果表明，TPAM至少部分通过促进OPC分化和轴突髓鞘形成，从而增强了中风后WM完整性。该提案将研究TPAM和潜在机制的新型WM修复增强作用。我们将测试以下总体假设：蛋白酶不活跃的TPAM治疗中风后的长期修复和长期神经系统恢复，至少部分通过通过PPAR促进OPC分化和轴突髓鞘形成。年轻的成年小鼠和老年小鼠都将进行测试。提出了三个具体目标。 AIM 1：确定用蛋白酶无效TPAM治疗的势后治疗是否可以增强WM完整性并促进长期神经系统恢复。 AIM 2：检验TPAM诱导的OPC分化/成熟并通过PPAR激活促进轴突髓鞘的假设。主要OPC和神经元OPC共培养系统将用于检验该假设。 AIM 3：检验TPAM诱导的OPC分化和轴突髓鞘化/再髓样的假设对于对WM完整性和中风后的长期神经恢复至关重要。