Making Embryonic Stem Cells Infarct Avid

使胚胎干细胞“热衷于梗死”

• 批准号: 7656884
• 负责人: Ming Zhao
• 金额: $ 22.73万
• 依托单位: MEDICAL COLLEGE OF WISCONSIN
• 依托单位国家: 美国
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-07-14 至 2011-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7656884
• 关键词: Acute myocardial infarction; Address; Affect; Affinity; Amines; Apoptosis; Apoptotic; Avidin; Avidity; Binding; Binding Proteins; Biotin; Blood Vessels; Carbohydrates; Cardiac; Cardiac Myocytes; Cell Death; Cell Therapy; Cell Transplants; Cell membrane; Cell physiology; Cell surface; Cells; Cellular Morphology; Chemistry; Data; Echocardiography; Engraftment; Goals; Image; Imaging technology; Infarction; Infusion procedures; Injection of therapeutic agent; Intravenous; Label; Lead; Light; Magnetic Resonance Imaging; Mediating; Methods; Modification; Monitor; Mus; Myocardial; Myocardial Infarction; Myocardium; Natural regeneration; Necrosis; Outcome; Patients; Phospholipids; Protein Binding; Proteins; Radionuclide Imaging; Recovery of Function; Site; Spatial Distribution; Specificity; Stem cell transplant; Stem cells; Structure; Surface; System; Testing; Therapeutic; Tissues; Transplantation; Work; cell type; complement C2a; embryonic stem cell; extracellular; implantation; improved; in vivo; minimally invasive; molecular marker; molecular recognition; mouse model; novel; pluripotency; prevent; public health relevance; repaired; stem cell therapy; synaptotagmin I; transplantation typing; uptake

DESCRIPTION (provided by applicant): The broad objective of this proposal is to enable embryonic stem cells (ESCs) to specifically recognize and bind to infarcted tissues, which they are expected to replace and regenerate. Cardiac repair by stem cell implantation holds promise as a post-infarct therapeutic option. Compared to intra- myocardial injection, intra-vascular infusion of stem cells is less invasive and better tolerated by patients with acute myocardial infarction (MI). However, the relatively low rate of ESC retention in the infarct site after transvascular infusion is a limiting factor that prevents sufficient engraftment and regeneration. To address the challenge, we will modify the stem cell surface so that transfused cells are able to bind to infarcted tissue by recognizing a well-defined molecular marker of cell death, anionic phospholipids (APLDs). APLDs become exposed to the extracellular milieu during apoptosis and necrosis, thereby providing a specific and ample binding target for the recognition of infarcted tissue by cognate moieties. Such a cognate moiety is the C2A domain of synaptotagmin I, a well- characterized APLDs-binding protein that recognizes dead and dying cells with high specificity and affinity. Recently, we demonstrated that intravenous-injected C2A avidly accumulates in infarcted myocardium. To logically extend this intriguing finding, we will apply this unique molecular recognition mechanism to mediate the engraftment of intravascularly delivered ESCs into infracted myocardium. The primary goal is to confer infarct avidity to ESCs by attaching the C2A to the ESC surface. As part of the Preliminary Studies, we have demonstrated that ESCs can be surface-labeled with C2A, without affecting cellular physiology or pluripotency. And, as a proof of feasibility, we have observed that C2A-conjugated ESCs bind dead cardiomyocytes, but not viable cardiomyocytes. In light of these preliminary data, we hypothesize that ESCs equipped with APLDs-binding activity will lead to a significantly improved engraftment within infarcted sites in vivo. To enhance therapeutic cardiac repair and to test this hypothesis, we propose the following Specific Aims: 1) to refine and optimize the conjugation methods for attaching the C2A to the surface of ESCs; and 2) to assess the engraftment rate of C2A-conjugated ESCs in infarcted cardiac tissue and evaluate the long-term cardiac function in a mouse model of acute MI. Once established, the concept of conferring infarct avidity should be applicable to other types of transplanted cells, including differentiated cell types derived from ESCs. Overall, this work explores a novel transplantation strategy that will aid in cardiac repair with translational potential. PUBLIC HEALTH RELEVANCE: Stem cell therapy holds promise in regenerating infarcted myocardium. While the intra-vascular delivery of stem cells is minimally invasive and better tolerated by patients, its efficacy is limited by a low retention rate of infused cells in the infarct site. The goal of this proposal is to make stem cells capable of recognizing and binding to infarcted tissues. This will be accomplished by attaching an infarct-avid protein to the stem cell surface without altering cellular physiology. Making stem cells with a binding affinity toward dead and dying tissues will not only help target transplanted stem cells to the infarct site, but also improve their rate of retention and engraftment within the infarcted tissues.

描述（由申请人提供）：该提案的主要目标是使胚胎干细胞（ESC）能够特异性识别并结合梗塞组织，预计它们会替代和再生这些组织。通过干细胞植入进行心脏修复有望成为梗塞后的治疗选择。与心肌内注射相比，干细胞血管内输注侵入性更小，急性心肌梗塞（MI）患者的耐受性更好。然而，经血管输注后，ESC 在梗塞部位的保留率相对较低，这是阻碍充分植入和再生的限制因素。为了应对这一挑战，我们将修改干细胞表面，以便输血细胞能够通过识别细胞死亡的明确分子标记物阴离子磷脂（APLD）来与梗塞组织结合。 APLD 在细胞凋亡和坏死过程中暴露于细胞外环境，从而为同源部分识别梗塞组织提供了特异性且充足的结合靶点。这样的同源部分是突触结合蛋白 I 的 C2A 结构域，突触结合蛋白 I 是一种经过充分表征的 APLD 结合蛋白，能够以高特异性和亲和力识别死亡和垂死细胞。最近，我们证明静脉注射的 C2A 在梗塞心肌中大量积聚。为了从逻辑上扩展这一有趣的发现，我们将应用这种独特的分子识别机制来介导血管内输送的 ESC 植入梗塞心肌。主要目标是通过将 C2A 连接到 ESC 表面来赋予 ESC 梗塞亲和力。作为初步研究的一部分，我们已经证明 ESC 可以用 C2A 进行表面标记，而不影响细胞生理学或多能性。而且，作为可行性的证明，我们观察到 C2A 缀合的 ESC 结合死亡的心肌细胞，但不结合存活的心肌细胞。根据这些初步数据，我们假设具有 APLD 结合活性的 ESC 将显着改善体内梗死部位的植入。为了增强治疗性心脏修复并检验这一假设，我们提出以下具体目标：1）完善和优化将 C2A 附着到 ESC 表面的缀合方法； 2) 评估梗死心脏组织中 C2A 缀合的 ESC 的植入率，并评估急性 MI 小鼠模型的长期心脏功能。一旦建立，赋予梗塞亲和力的概念应该适用于其他类型的移植细胞，包括源自ESC的分化细胞类型。总体而言，这项工作探索了一种新颖的移植策略，该策略将有助于具有转化潜力的心脏修复。公共健康相关性：干细胞疗法有望再生梗塞心肌。虽然干细胞的血管内输送是微创的并且患者耐受性更好，但其功效受到梗塞部位输注细胞保留率低的限制。该提案的目标是使干细胞能够识别并结合梗塞组织。这将通过将梗塞亲和蛋白附着到干细胞表面而不改变细胞生理学来实现。使干细胞对死亡和濒临死亡的组织具有结合亲和力，不仅有助于将移植的干细胞靶向梗塞部位，而且还可以提高它们在梗塞组织内的保留和植入率。