Perlecan Domain V is a Novel Promoter of Brain Repair after Stroke

描述(申请人提供)：中风是美国第三大死亡原因，也是导致严重、长期残疾的主要原因。然而，尽管急性中风的治疗取得了进展，但我们对中风后大脑自我修复机制的了解仍然很差。因此，大脑修复和中风康复问题是一个新兴的研究重点，其根本目标是识别和改进大脑修复过程。据报道，脑修复发生在一个紧密的时空神经血管缝隙中，包括血管重建(血管生成)和神经元再繁殖(神经再生)。我们假设，中风后的大脑刺激血管生成和神经血管生态位的形成，部分是通过产生细胞外基质(ECM)的生物活性片段perlecan。我们的假设是基于几个关键的观察结果，包括我们的初步数据：中风导致蛋白水解性产生Perlecan的生物活性片段，Perlecan是所研究的最具蛋白酶敏感性的ECM成分，并且Perlecan是血管生成和神经发生所必需的。我们的初步研究表明，Perlecan的C-末端片段，结构域V(DV)，先前已发现的血管生成修饰物，1)在中风后脑内上调，2)在体外和体内促进脑血管生成，3)增加脑源性神经营养因子(BDNF)的脑内皮细胞分泌，BDNF是神经血管利基中重要的促血管生成、神经保护和迁移促进因子，4)可能通过促血管生成(5(1)整合素)发挥这些作用。在这一新知识的推动下，我们现在计划1)确定DV在脑血管生成和神经血管生态位形成中的作用，2)确定DV影响脑血管生成和神经血管生态位形成的整合素相关信号通路，以及3)确定DV对卒中后脑修复的重要性和治疗潜力。具体地说，我们计划证明DV通过与(5(1)整合素和随后释放的BDNF相互作用来刺激脑血管生成和神经血管生态位的形成，并证明DV促进中风后的脑修复。提出的研究具有重要意义，因为他们调查了大脑和非脑血管生成之间的差异，试图建立一种新的卒中后大脑自我修复机制以用于治疗利用，并提出了比目前使用的卒中疗法明显更长的治疗窗口。我们的研究是创新的，因为它表明脑损伤产生的ECM片段可能具有有益的影响，并确定了脑内皮细胞BDNF释放的新原因。我们的长期目标是开发DV作为一种人类中风疗法。 公共卫生相关性：在美国，中风是第三大死亡原因，也是导致严重、长期残疾的主要原因。然而，尽管在努力将中风后的脑损伤降至最低方面取得了进展，但人们对如何刺激受损脑组织的修复知之甚少。因此，我们建议在卒中动物模型中研究卒中产生的蛋白片段的潜在益处，目的是开发一种新型的人类卒中疗法。

DESCRIPTION (provided by applicant): Stroke is the third leading cause of death and the leading cause of serious, long-term disability in the U.S. However, while advances have been made in acute stroke treatment, our understanding of the mechanisms underlying brain self-repair after stroke remains poor. Therefore, the problem of brain repair and stroke rehabilitation is an emerging research priority, with the underlying goal of identifying and improving brain reparative processes. Brain repair reportedly occurs in a close temporal-spatial neurovascular niche of revascularization (angiogenesis) and neuronal repopulation (neurogenesis). We hypothesize that the post-stroke brain stimulates angiogenesis and neurovascular niche formation in part by generating a bioactive fragment of the extracellular matrix (ECM), perlecan. Our hypothesis is based on several key observations including our preliminary data: Stroke results in proteolytic generation of bioactive fragments of perlecan, the most protease-sensitive ECM component studied, and perlecan is required for both angiogenesis and neurogenesis. Our preliminary studies indicate that the C-terminal fragment of perlecan, domain V (DV), a previously identified modifier of angiogenesis, 1) is upregulated in the brain after stroke, 2) enhances brain angiogenesis in vitro and in vivo, 3) increases brain endothelial cell secretion of brain derived neurotrophic factor (BDNF), an important pro-angiogenic, neuroprotective and migration promoting factor in the neurovascular niche, and 4) may exert these effects through the pro-angiogenic (5(1 integrin. Empowered by this new knowledge, we now plan to 1) Determine the role of DV in brain angiogenesis and neurovascular niche formation, 2) Determine the integrin-related signaling pathway by which DV affects brain angiogenesis and neurovascular niche formation, and 3) Determine the importance and therapeutic potential of DV to post-stroke brain repair. Specifically, we plan to demonstrate that DV stimulates brain angiogenesis and neurovascular niche formation via interaction with the (5(1 integrin and subsequent release of BDNF, and demonstrate that DV enhances post-stroke brain repair. The proposed studies are significant in that they investigates differences between brain and nonbrain angiogenesis, seek to establish a novel mechanism of post-stroke brain self-repair for therapeutic exploitation, and suggests a significantly longer therapeutic window than currently employed stroke therapies. Our investigation is innovative because it suggests that ECM fragments generated by brain injury could possess beneficial effects and identifies a novel cause of brain endothelial cell BDNF release. Our long term goal is to develop DV as a human stroke therapy. PUBLIC HEALTH RELEVANCE: Stroke is the third leading cause of death and the leading cause of serious, long-term disability in the U.S. However, while advances have been made in trying to minimize brain injury after stroke, little is known about how to stimulate repair of injured brain tissue. Therefore, we propose to study the potential benefits of a stroke-generated protein fragment in a stroke animal model, with the goal of developing a new type of human stroke therapy.