Homing and Genetic Modification of Mesenchymal Stem Cell

描述(由申请人提供)： 冠状动脉血管闭塞可导致心肌梗死，随后心肌细胞丢失，最终形成疤痕。其结果是肌肉功能丧失，可能导致充血性心力衰竭，甚至可能死亡。人们已经做了许多尝试来再生心脏血管和心肌。已有研究表明，骨髓来源的干细胞可迁移至受损心肌，然后分化为内皮细胞和心肌细胞，心功能部分恢复。我们和其他人已经证明，骨髓间充质干细胞(MSCs)可能参与心肌内注射后的心脏修复。基于特定信号对MSCs在心肌上的归巢和黏附以及随后在心肌中的植入的假设，我们建议研究以下特定目标：1)优化有分化为心肌细胞的MSCs的分离条件，并进一步鉴定这些MSCs；2)确定介导MSCs归巢到缺血心肌的化学信号和黏附受体；3)进一步丰富表达介导特定心肌归巢的受体/配体的MSCs亚群，并对这些MSCs进行基因修饰，以增强对缺血心肌的归巢和黏附；4)确定全身输送浓缩和/或修饰的MSCs是优于全身输送还是直接心肌内输送未修饰的MSCs以达到心脏再生和心功能恢复的目的。由于分化为心肌细胞的MSCs的表型尚不确定，我们计划优化分化为心肌细胞的MSCs的分离条件，并进一步表征这一亚群MSCs的特征。利用基因组学和蛋白质组学，我们将筛选哪些细胞因子和黏附受体在缺血心肌中上调，以及这些细胞因子是否可以用于促进MSCs向心肌的运输和归巢。在确定了归巢和植入过程中不可或缺的细胞因子和黏附受体后，我们将对MSCs进行遗传操作(例如，过度表达细胞因子受体或特定的黏附配体)，并确定这一策略是否会增强MSCs的存活、归巢和植入到缺血心肌。最后，我们将研究全身注射转基因MSCs是否是直接心肌内注射用于心脏修复和再生的更好的治疗策略。这种增强心肌归巢和植入过程的特定操作将改善缺血性心脏病和充血性心力衰竭的治疗选择。

DESCRIPTION (provided by applicant): Coronary vascular occlusion can lead to myocardial infarction with subsequent loss of myocardial cells, and eventual scar formation. The consequence is loss of muscular function that can lead to congestive heart failure and possibly, death. Numerous attempts have been made to regenerate cardiac vessels and the myocardium. It has been demonstrated that bone marrow-derived stem cells migrate to the injured myocardium and then differentiate into both endothelial and myocardial cells, with partial restoration of cardiac function. We and others have shown that mesenchymal stem cells (MSCs) may participate in cardiac repair after intra-myocardial injection. Based on the hypothesis that specific signals are responsible for the homing and adherence of MSCs to myocardium and subsequent engraftment in the myocardium, we propose to study the following specific aims: 1) to optimize the conditions for isolation of MSCs that have capacity to differentiate into cardiac myocytes, and to further characterize these MSCs 2) to determine the chemical signals and adhesion receptors that mediate homing of MSCs to ischemic myocardium; 3) to further enrich for the sub-set of MSCs that expresses receptors/ligands that mediate specific myocardial homing and to genetically modify these MSCs so as to enhance homing and adhesion to the ischemic myocardium, 4) to determine whether systemic delivery of enriched and/or modified MSCs is a superior strategy to systemic delivery, or direct intra-myocardial delivery of non-modified MSCs for purposes of cardiac regeneration and recovery of cardiac function. Since the phenotype of MSCs that differentiate into cardiac myocytes is uncertain, we plan to optimize conditions for the isolation of MSCs that differentiate into cardiac myocytes, and to further characterize the "signature" of this sub-population of MSCs. Using genomics and proteomics, we will then screen which cytokines and adhesion receptors are upregulated in the ischemic myocardium, and whether these cytokines can be used to enhance trafficking and homing of MSCs to the myocardium. Having identified cytokines and adhesion receptors integral to the homing and engraftment process, we will perform genetic manipulations on MSCs (for example, to over express cytokine receptors or specific adhesion ligands) and determine whether this strategy will enhance viability, homing and engraftment of MSCs to the ischemic myocardium. Finally, we will examine if systemic administration of genetically modified MSCs is a superior therapeutic strategy to direct intramyocardial injection for cardiac repair and regeneration. Such specific manipulations to enhance the process of homing and engraftment to the myocardium will improve therapeutic options for ischemic heart disease and congestive heart failure.