Mechanisms underlying Netrin-1-mediated functional recovery after stroke

描述(由申请人提供)： 在美国，中风仍然是导致长期残疾的主要原因。为促进卒中后功能恢复，急需合适的康复策略。神经血管单位的概念和继发性损伤所涉及的多种机制正在改变我们在中风治疗中的方法。在局灶性脑缺血后，尽管梗死区周围皮质的组织灌注量逐渐改善，但即使在几个月后也无法完全恢复。很明显，局部血流动力学的恢复也影响了脊柱密度的恢复，最终影响了突触的可塑性。我们的初步结果证实，AAVNetrin-1基因治疗诱导的功能恢复与梗死灶周围皮质血管密度的增加有关，这可能与Netrin-1‘S的促血管生成作用或预防继发性损伤有关。基于这些有希望的结果和Netrin-1在抗炎和神经可塑性诱导中的不同作用，我们希望进一步研究Netrin-1在脑缺血和功能恢复背景下减轻炎症和促进神经可塑性的治疗效果和潜在的信号机制。目的1.验证Netrin-1基因转移通过腺苷2B受体减轻卒中后慢性神经炎的假说。为了区分血液和内皮A2B受体的作用，我们将使用骨髓移植来创造嵌合小鼠。目的2验证Netrin-1基因转移通过特异性Netrin-1受体促进神经干细胞在脑梗塞周围区和白质中迁移的假说。目的3验证Netrin-1基因转移增强苯丙胺神经可塑性诱导和康复作用的假说。在这里收集的概念验证数据可能导致Netrin-1作为促进功能恢复的中风治疗的新靶点的发展。 公共卫生相关性： 在美国，中风仍然是导致长期残疾的主要原因。虽然大多数中风患者在侮辱后的几周到几个月内会有一定程度的恢复，但越来越明显的是，促进中风患者的康复需要适当的康复治疗。尽管在动物研究方面取得了进展，但临床试验普遍未能证明临床应用所需的患者预后的强劲和显著改善。由于大脑的复杂性，继发性损伤和恢复涉及多个通路的级联。人们越来越认识到，需要针对多个途径的治疗来改善患者的预后。我们的初步研究表明，netrin-1基因治疗改善了神经结构和功能。这项拟议的研究将为以Netrin-1为靶点的中风康复辅助治疗的未来发展建立概念验证证据。

DESCRIPTION (provided by applicant): Stroke remains the leading cause of long-term disability in the US. To enhance post stroke functional recovery, appropriate rehabilitation strategy is in dire need. The concept of neurovascular unit and the multiple mechanisms involved in secondary injury is changing our approach in stroke therapy. Following focal cerebral ischemia, although the tissue perfusion in the peri-infarct cortex improved gradually in a distance-dependent manner, it is never fully restored even months after. It is evident that the recovery of local hemodynamics also affected the recovery of spine density, and ultimately, synaptic plasticity. Our preliminary results establish that functional restoration induced by AAV-Netrin-1 gene therapy is associated with an increase in vascular density in the peri-infarct cortex, which could be related to netrin-1's proangiogenic effect or prevention of secondary injury. Based on these promising results and the diverse effects of netrin-1 in anti-inflammation and neuroplasticity induction, we would like to extend our study to further investigate the therapeutic efficacy of netrin-1 and underlying signaling mechanisms in reducing inflammation and promoting neuroplasticity in the context of brain ischemia and functional recovery. The following specific aims are proposed: Aim 1. Test the hypothesis that netrin-1 gene transfer reduces post stroke chronic neuroinflammation via adenosine 2B receptor. To distinguish the contribution of blood versus endothelial A2B receptors, we will use bone marrow transplants to create chimeric mice. Aim 2 will test the hypothesis that netrin-1 gene transfer enhances neural stem cell migration in the ischemic peri-infarct and white matter via specific netrin-1 receptors. Aim 3 will test the hypothesis that netrin-1 gene transfer augments the neuroplasticity inducing effect of amphetamine and rehabilitation. Proof-of-concept data collected here may lead to the development of netrin-1 as a novel target for stroke therapy in promoting functional recovery. PUBLIC HEALTH RELEVANCE: Stroke remains the leading cause of long-term disability in the US. Although most stroke patients make some degree of recovery in weeks to months after the insult, it has become increasingly apparent that promoting recovery in the stroke patients requires appropriate rehabilitation therapy. Despite the progress made in animal research, clinical trials have generally failed to demonstrate the robust and significant improvement in patient outcome necessary for clinical application. Due to the complexity of our brain, multiple cascades of pathways are involved in secondary injury and recovery. There is a growing recognition that therapies targeting more than one pathway are needed to improve patient outcome. Our preliminary study suggests that netrin-1 gene therapy improves the neural structure and function. This proposed study will establish proof-of-concept evidences for future development of adjuvant therapeutics targeting netrin-1 in stroke rehabilitation.