VEGF ligand presentation and therapeutic angiogenesis

摘要 在美国，中风是导致残疾的主要原因，除了物理治疗外，治疗方案还可以减少 这种负担是不存在的。中风后，细胞死亡和神经胶质瘢痕形成导致非 再生梗死区周围环绕的再生卒中空洞。我们有兴趣了解 生物工程疗法如何与梗死周边地区活跃的促修复计划协同作用 促进中风腔内组织再生，从而促进神经功能恢复。我们之前已经 设计了一种双重作用的血管生成水凝胶，当注射到中风腔内时，可以减少胶质瘢痕形成 并促进血管形成，使轴突得以渗透。虽然在中风腔内实现大脑修复是 值得注意的是，这些结果是在神经可塑性未受损害的年轻小鼠身上取得的。我们相信，要带来这一点 技术更接近临床翻译，我们必须能够在更多方面表现出类似的大脑修复和行为改善 临床上相关的动物模型，如神经可塑性降低的衰老小鼠。在此应用程序中，我们的目标是识别 我们的血管生成水凝胶的作用机制，并优化其配方，并将这一新配方用于 一种神经可塑性降低的中风模型。水凝胶由透明质酸组成，官能化后 细胞结合整合素并负载聚集性血管内皮生长因子和肝素 纳米粒子。肝素是一种已知的抗炎药，其潜在作用是通过破坏炎症 中风后巨噬细胞和星形胶质细胞之间的循环。我们将使用实验方法论的设计来 确定这三个因素(整合素、聚集的血管内皮生长因子和肝素纳米粒)的组成 导致实质性的大脑修复(目标1)，并评估水凝胶成分如何调节修复前 通过分析中风后蛋白质、信使核糖核酸和免疫细胞群的时间变化来分析环境 (目标2)。使用改进的配方，我们还将评估血管生成水凝胶的促进能力 更严格的动物模型的神经再生和功能恢复，特别是老年小鼠 脑缺血后即刻及幼年脑缺血小鼠作为可塑性窗口的治疗 正在关闭(目标3)。总体而言，我们的目标是加深对生物工程疗法如何协同作用的理解 通过内源性促再生计划，从而改善中风后的行为结果 难以治疗的病例。

Summary Stroke is the leading cause of disability in the US, and, apart from physical therapy, therapeutic options to reduce this burden are non-existent. Following a stroke, cell death and glial scarring leads to the formation of a non- regenerative stroke cavity surrounded by the regenerative peri-infarct region. We are interested in understanding how bioengineered therapeutics can synergize with pro-repair programs active in the peri-infarct region to promote tissue regeneration in the stroke cavity and thereby improve neurological recovery. We have previously engineered a dual-acting angiogenic hydrogel that, when injected into the stroke cavity, can reduce glial scarring and promote vascularization to allow axonal infiltration. Although achieving brain repair in the stroke cavity is remarkable, these results were achieved in young mice with un-impaired neuroplasticity. We believe that to bring this technology closer to clinical translation, we must be able to show similar brain repair and behavioral improvement in more clinically relevant animal models, like aged mice with decreased neuroplasticity. In this application, we aim to identify our angiogenic hydrogel’s mechanism of action and optimize its formulation and to utilize this new formulation in a stroke models with decreased neuroplasticity. The hydrogel is composed of hyaluronic acid functionalized with cell-binding integrins and loaded with clustered vascular endothelial growth factor (VEGF) and heparin nanoparticles. Heparin is a known anti-inflammatory agent that potentially acts by breaking the inflammatory cycle between macrophages and astrocytes following stroke. We will use design of experiment methodology to determine the composition of these three factors (integrins, clustered VEGF, and heparin nanoparticles) that leads to substantial brain repair (Aim 1) and assess how the hydrogel components modulate the pro-repair environment by analyzing temporal changes in proteins, mRNA, and immune cell populations following stroke (Aim 2). Using the improved formulation, we will also evaluate the angiogenic hydrogel’s ability to promote neurological regeneration and functional recovery in more rigorous animal models, specifically aged mice treated immediately following cerebral ischemia and young mice with cerebral ischemia treated as the plasticity window is closing (Aim 3). Overall, we aim to deepen our understanding of how bioengineered therapeutics synergize with endogenous pro-regenerative programs and thereby improve behavioral outcomes following stoke in more difficult-to-treat cases.