Engineered Induction of a Stem Cell Homing Response

描述(由申请人提供)：非常需要帮助心肌梗死后缺血组织修复或再生的治疗策略，特别是可以改善治疗细胞(即干细胞)植入的治疗方法。心肌梗死通常会导致梗死区的心肌细胞死亡，最终导致心脏的病理性重构。这会导致严重的后果，如心脏扩张、室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(利用外源性细胞来源)自然干细胞归巢机制的治疗策略显示出在心肌梗死后保存和恢复心输出量的前景。尽管人体试验的结果好坏参半，但某些负面结果可能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，可以用来有效地将任何潜在的归巢受体整合到细胞表面，用于系统的细胞靶向。我们已经证明，在间充质干细胞(MSCs)表面掺入归巢受体可以导致强大的归巢反应，这是我们在生理模拟条件下通过体外细胞滚动实验所表征的。我们还表明，我们的方法可以用来显著增强系统注入的MSCs在小鼠炎症模型中的归巢。重要的是，我们已经确定了保持MSC活性、细胞黏附、增殖和多分化能力的修饰条件。这项工作的目标是在MSCs表面进行工程，以提高其向心血管疾病部位的转运效率，并在不影响其固有特性的情况下改善归巢反应的均质性，包括其通过血管内皮细胞的迁移能力。我们最初的努力将集中在连接生物素化配体以诱导强大的细胞滚动反应。为了迁移到血管外空间，循环细胞必须迅速与血管内皮细胞的特定部位发生强烈的黏附和停滞，同时抵抗血管壁上的持续剪切力。由于白细胞的选择性黏附不会导致牢固的黏附和转位，除非另一组黏附分子-整合素被激活，我们计划用针对炎症部位或缺血组织内内皮表达的整合素的抗体来共同固定滚动的配体。

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.