Engineered Induction of a Stem Cell Homing Response

描述（由申请人提供）：对心肌梗死后缺血组织修复或再生的治疗策略有很大的需求，特别是可以改善治疗细胞（即干细胞）植入的治疗策略。心肌梗死通常导致梗死区心肌细胞死亡，最终导致心脏的病理性重塑。这可能导致严重的后果，如心脏扩张，壁变薄和收缩功能恶化，导致充血性心力衰竭。旨在利用或增强（外源细胞源）天然干细胞归家机制的治疗策略有望保护和恢复心肌梗死后的心输出量。虽然人体试验的结果喜忧参半，但某些负面结果可以用低效的归巢机制来解释。我们最近开发了一种简单的平台策略，可用于有效地将任何潜在的归巢受体结合到细胞表面，以进行系统的细胞靶向。我们已经证明，将归巢受体结合到间充质干细胞（MSCs）表面可以导致强大的归巢反应，我们已经通过生理模拟条件下的体外细胞滚动实验来表征。我们还表明，我们的方法可用于显著增强小鼠炎症模型中全身注入的MSCs的归巢。重要的是，我们已经确定了维持MSC活力、细胞粘附、增殖和多分化能力的修饰条件。这项工作的目标是设计MSCs的表面，以提高其转运到心血管疾病部位的效率，并在不影响其固有特性（包括通过血管内皮迁移的能力）的情况下改善归巢反应的同质性。我们最初的努力将集中在附着生物素化配体上，以诱导强大的细胞滚动反应。为了迁移到血管外空间，循环细胞必须在抵抗血管壁持续剪切力的同时，迅速形成与血管内皮特定部位的强粘附和阻滞。由于选择依赖的白细胞粘附不会导致牢固的粘附和转运，除非另一组粘附分子（整合素）参与其中，我们计划将滚动配体与针对炎症部位内皮或缺血组织内表达的整合素的抗体共同固定。

DESCRIPTION (provided by applicant): There is a great need for therapeutic strategies that aid in the repair or regeneration of ischemic tissue following myocardial infarction, especially therapies that can improve the engraftment of therapeutic cells (i.e. stem cells). Myocardial infarction typically leads to death of cardiomyocytes in the infarct zone that culminates in pathological remodeling of the heart. This can cause severe consequences such as cardiac dilation, wall thinning and deterioration of contractile function leading to congestive heart failure. Therapeutic strategies that aim to harness or enhance (with an exogenous cell source) natural stem cell homing mechanisms show promise to preserve and restore cardiac output following myocardial infarction. Although results in human trials are mixed, certain negative results may be explained by inefficient homing mechanisms. We have recently developed a simple platform strategy that can be used to effectively incorporate potentially any homing receptor onto a cell surface for systemic cell targeting. We have shown that incorporation of homing receptors onto the surface of mesenchymal stem cells (MSCs) can lead to a robust homing response which we have characterized via in vitro cell rolling experiments under physiologically simulated conditions. We have also shown that our approach can be used to significantly enhance the homing of systemically infused MSCs within a murine model of inflammation. Importantly, we have determined modification conditions that maintain MSC viability, cell adhesion, proliferation, and multi-differentiation capacities. The goal of this work is to engineer the surface of MSCs to enhance their trafficking efficiency to site of cardiovascular disease, and improve the homogeneity of the homing response without affecting their native properties, including their ability to transmigrate through vascular endothelium. Our initial efforts will focus on attaching biotinylated ligands to induce a robust cell rolling response. To emigrate to extravascular spaces, circulating cells must rapidly develop strong adhesion to, and arrest on specific sites of vascular endothelium while resisting continuous shear forces at the vessel walls. Since selecting-dependent adhesion of leukocytes does not lead to firm adhesion and transmigration unless another set of adhesion molecules, the integrins, are engaged, we plan to co-immobilize rolling ligands with antibodies that target integrins that are expressed on endothelium at sites of inflammation or within ischemic tissue. PUBLIC HEALTH RELEVANCE: The aim of this proposal is to engineer the surface of mesenchymal stem cells to enhance their trafficking efficiency to sites of cardiovascular disease, and improve the homogeneity of the homing response without affecting their native properties, including their ability to transmigrate through vascular endothelium and capacity for multi-lineage differentiation. The development of this novel approach will have broad implications for wound repair and treatment of many tissues where cell based therapies is appropriate. Potential benefits for treatment of ischemic tissue following myocardial infarction include increased cardiac output leading to increased survival and improved quality of life.