Dynamic ECM-Mimicking Biomaterials for Ischemia Treatment

用于治疗缺血的动态ECM仿生材料 目前，外周动脉疾病(PAD)是全球心血管疾病发病率的第三大常见原因 在20%的65岁以上的人口中。如果不对PAD进行治疗，它可能会发展为严重的肢体缺血，导致组织 坏死并最终截肢。血管生成，祖细胞形成新生血管的过程 细胞，可能被证明是一种有效的治疗策略。血管生成可以通过输送血管来完成 最近出现的人诱导多能干细胞(hiPSCs-EPs)来源的祖细胞 作为一种有希望的、针对患者的治疗方法。然而，IPSCs-EPs嫁接的最佳条件和 具体来说，与宿主血管系统的吻合尚不清楚，因为潜在的分子机制 引导这些细胞的自我组装进入血管网络还知之甚少。 为了克服这一障碍，我们建议开发工程化的血管生成水凝胶，呈现可调节的 在细胞-基质界面的信号，可以增强IPSC-EPs的治疗性血管生成 外周缺血恢复并确定基质特性的潜在机制 控制血管生成。 我们和其他人之前的工作表明，稳定的血管网络的形成取决于细胞类型和 基质特性，如刚性和降解性。高度可降解的基质，如胶原蛋白，可以支持 最初的血管生成，但长期的稳定性是具有挑战性的。此外，这些矩阵属性是耦合的 并在不同时间尺度上影响血管内皮细胞和血管周围细胞在新生血管网络形成中的萌发。 因此，我们假设对局部基质力学和降解性的时间和现场控制 合成基质将协同调节HiPSC-EPs的血管形态发生，导致稳定、成熟 形成血管网络，促进后肢缺血恢复。为了检验我们的假设，我们提出了一个 胶原和降冰片烯修饰的透明质酸组成的杂化互穿水凝胶网络 (COL/NorHA)。该系统的优点是结合了由胶原结合位点呈现的自然提示 纤维状结构，具有合成NorHA的原位动态可调性。我们的目标是1)阐明 依赖时间的基质特性和支配血管网络发育的机制之间的相互作用 2)促进PAD的治疗性血管生成。在目标1中，我们将调节这些水凝胶中的弹性 使用原位交联反应。我们将研究在特定时间点的僵硬如何影响由此产生的 皮肤皱褶模型中体外和体内的血管生成反应。在目标1的补充方法中，在 目的2利用COIL/NorHA分离基质降解性对IPSC-EPs血管生成潜能的影响 其中蛋白分解敏感性与基质金属蛋白酶可降解肽一起调节的IPN。在目标3中，我们 将测试耦合基质力学和降解性对IPSC来源的毛细血管丛的协同影响 队形。具体地说，我们将阐明体外培养的血管神经丛的成熟水平如何使 与宿主血管系统体内灌流。 综上所述，我们建议加强ipsc-EPs治疗外周动脉疾病的血管生成。 通过使用可调的Coll/NorHA IPN控制工程基质属性进行治疗，该IPN模仿 原生ECM的层次化时间结构。阐明基质性质和基质之间的相互作用 管理血管网络发展的机制将确定可能是 部署在临床上，以改善患者的血管健康并帮助建立疾病模型。

Dynamic ECM-Mimicking Biomaterials for Ischemia Treatment Peripheral artery disease (PAD) is the third most common cause of cardiovascular morbidity worldwide, present in 20% of the population over 65. If PAD is not treated, it can progress to critical limb ischemia, resulting in tissue necrosis and eventual limb amputation. Vasculogenesis, the process of de novo vessel formation from progenitor cells, may prove an effective therapeutic strategy. Vasculogenesis may be accomplished by delivering vascular progenitor cells derived from human induced pluripotent stem cells (hiPSCs-EPs), which have recently emerged as a promising, patient-specific therapy. However, the optimal conditions for iPSCs-EPs engraftment and anastomosis with the host vasculature are unclear, specifically, since the underlying molecular mechanisms that guide these cells' self-assembly into vascular networks are poorly understood. To overcome this hurdle, we propose to develop engineered vasculogenic hydrogels, presenting tunable cues at the cell-matrix interface, that can enhance the therapeutic vasculogenesis of iPSC-EPs for peripheral ischemia recovery and define the underlying mechanisms through which matrix properties control vasculogenesis. Previous work by us and others has shown that stable vascular network formation depends on both cell type and matrix properties such as stiffness and degradability. Highly degradable matrices such as collagen may support vasculogenesis initially, but long-term stability is challenging. Furthermore, these matrix properties are coupled and impact endothelial and perivascular cell sprouting at different time scales in neo-vascular network formation. Therefore, we hypothesize that temporal, in situ control over local matrix mechanics and degradability in synthetic matrices will synergistically regulate the vascular morphogenesis of hiPSC-EPs, lead to stable, mature vascular network formation and improve hind limb ischemia recovery. To test our hypothesis, we propose a hybrid interpenetrating hydrogel network (IPN) comprised of collagen and norbornene-modified hyaluronic acid (Coll/NorHA). This system has the advantage of combining the natural cues presented by collagen binding sites and fibrous architecture with the in situ dynamic tunability of synthetic NorHA. Our goal is to 1) elucidate the interplay between time-dependent matrix properties and mechanisms that govern vascular network development and 2) enhance therapeutic vasculogenesis for PAD. In Aim 1, we will modulate the elasticity in these hydrogels using in situ cross-linking reactions. We will study how stiffening at specific timepoints impacts the resulting vasculogenic response both in vitro and in vivo in a skin fold model. In a complementary approach to Aim 1, in Aim 2, we will isolate the effects of matrix degradability on iPSC-EPs vasculogenic potential using Coll/NorHA IPNs in which proteolytic susceptibility is tuned with matrix metalloprotease-degradable peptides. In Aim 3, we will test the synergistic impact of coupling matrix mechanics and degradability on iPSC-derived capillary plexus formation. Specifically, we will elucidate how the maturation level of the in vitro grown vascular plexus enables in vivo perfusion with host vasculature. In summary, we propose to enhance therapeutic vasculogenesis of iPSC-EPs for peripheral artery disease treatment through control of engineered matrix properties using a tunable Coll/NorHA IPN that mimics the hierarchical temporal structure of native ECM. Elucidating the interplay between matrix properties and mechanisms that govern vascular network development will identify angiogenic biomaterials that may be deployed in the clinic to improve patients' vascular health and aid in disease modeling.