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）：该提案的广泛目标是使胚胎干细胞（ESC）专门识别并与梗塞的组织结合，他们有望取代和再生。干细胞植入的心脏修复有望作为侵入后治疗选择。与心肌注射相比，急性心肌梗死（MI）患者的干细胞内血管内输注较少，并且可以更好地耐受性耐受性。但是，血管内输注后梗塞部位的ESC保留率相对较低，是防止足够的植入和再生的限制因素。为了应对挑战，我们将修改干细胞表面，以使输血细胞能够通过识别明确定义的细胞死亡，阴离子磷脂（APLDS）来与梗塞组织结合。 APLD在细胞凋亡和坏死期间暴露于细胞外环境，从而提供了一个特定且足够的结合靶标，以通过认知部分识别梗塞组织。这种认知部分是突触毒素I的C2A结构域，这是一种良好的APLD结合蛋白，它识别具有高特异性和亲和力的死亡和垂死的细胞。最近，我们证明了静脉注射的C2a在梗塞心肌中均匀积累。为了扩展这一有趣的发现，我们将采用这种独特的分子识别机制来介导植入血管内递送的ESC的移植到违规的心肌中。主要目标是通过将C2A连接到ESC表面来赋予ESC的梗塞伴随。作为初步研究的一部分，我们证明了ESC可以用C2A表面标记，而不会影响细胞生理或多能性。而且，为了证明可行性，我们观察到C2A偶联的ESC结合了死心肌细胞，但不是可行的心肌细胞。鉴于这些初步数据，我们假设配备APLDS结合活动的ESC将导致体内梗塞位点内的植入显着改善。为了增强治疗性心脏修复并检验该假设，我们提出了以下特定目的：1）精炼和优化将C2A连接到ESC表面的共轭方法； 2）评估梗塞心脏组织中C2A偶联ESC的植入率，并评估急性MI小鼠模型中的长期心脏功能。建立后，赋予梗塞亲和力的概念应适用于其他类型的移植细胞，包括来自ESC的分化细胞类型。总体而言，这项工作探讨了一种新型的移植策略，该策略将有助于具有转化潜力的心脏修复。公共卫生相关性：干细胞疗法在再生梗塞心肌方面有希望。虽然干细胞的血管内递送是最小的侵入性，并且患者的耐受性更好，但其功效受到梗塞部位注入细胞的较低保留率的限制。该建议的目的是使干细胞能够识别和结合梗塞组织。这将通过在不改变细胞生理的而不改变细胞生理的情况下将梗死蛋白附着在干细胞表面上来实现。使对死亡和垂死组织具有结合亲和力的干细胞不仅有助于将移植的干细胞靶向梗塞部位，而且还提高了其在梗塞组织中的保留率和植入率。