Molecular Engineering of Damaged Myocardium To Enhance Regeneration And Repair

描述(由申请人提供)：在成人心脏中发现心脏祖细胞(CPC)导致了对心脏病新疗法的更高期望。然而，CPC的过继转移只会导致短暂的心功能改善，因为大多数捐赠的细胞无法在缺血瘢痕的恶劣环境中存活。虽然大多数方法侧重于增强干细胞的能力，但对受损心肌进行工程化是增强心肌修复和再生的有效替代策略。细胞外基质(ECM)蛋白是心肌环境的关键成分，对维持细胞功能非常重要。因此，这项建议的总体目标是通过改变纤维连接蛋白(FN)的表达来改善CPC在受损心肌中的存活、增殖、募集和持久性。FN是一种与心脏中CPC的时空出现高度相关的ECM蛋白。我们的初步数据描述了调控CPC生长和存活的Fn-5？1-FAK-Pim-1信号级联。Fn、β5？1、FAK和Pim-1在心肌细胞生物学中的相关性已被广泛接受，然而，到目前为止，关于这一途径在CPC中的作用尚不清楚。因此，近期的目标是了解FN-51-FAK-Pim-1通路在CPC中的病理条件下的意义，并推测一种创新的治疗方法来工程受损心肌的细胞外环境，以促进再生和修复。这些发现的翻译潜力将被探索使用腺相关病毒9型(AAV9)载体来表达功能性胶原结合的FN片段，该片段旨在增强CPC的存活、增殖、募集和植入。我们的目标是：1)Fn-1-FAK-Pim-1信号轴在活体心肌损伤后被触发；2)FN激活整合素受体通过FAK-Pim-1信号诱导CPC立即早期应激反应、存活和增殖；3)强大和持久的CPC依赖的再生是由亲心肌AAV9载体携带的胶原结合Fn片段的过表达介导的。这些研究的意义在于确定内源性修复对损伤反应的有益方面。长期目标是将表达AAV9方案的FN片段转移到人类疾病中，为再生医学建立一个创新的治疗概念。

DESCRIPTION (provided by applicant): Discovery of cardiac progenitor cells (CPCs) in the adult heart has led to heightened expectations for novel treatments of cardiac disease. However, adoptive transfer of CPCs results only in transient improvement of cardiac performance because most of the donated cells fail to persist in the hostile milieu of the ischemic scar. Whereas most approaches focus upon enhancing capabilities of stem cells, engineering of the damaged myocardium is a valid alternative strategy to enhance myocardial repair and regeneration. Extracellular matrix (ECM) proteins are pivotal components of the myocardial environment important in maintenance of cellular function. Therefore, the overall goal of this proposal is to improve the survival, proliferation, recruitment, and persistence of CPC in the damaged myocardium by modification of fibronectin (Fn) expression, an ECM protein which correlates highly with spatio-temporal appearance of CPCs in the heart. Our preliminary data delineate a Fn-?5?1-FAK-Pim-1 signaling cascade that regulates CPC growth and survival. The relevance of Fn, ?5?1, FAK and Pim-1 in cardiomyocyte biology are well accepted, however, nothing is known so far about this pathway in CPCs. Therefore, the short term goal is to understand the significance of the Fn-?5? 1-FAK-Pim-1 pathway in CPCs under pathological conditions and extrapolate an innovative therapeutic approach to engineer the extracellular environment of the damaged myocardium to enhance regeneration and repair. Translational potential of these findings will be explored using an adeno-associated virus type 9 (AAV9) vector to express a functional collagen-tethered Fn fragment designed to enhance CPC survival, proliferation, recruitment, and engraftment. Our specific aims are: 1) The Fn-?5?1-FAK-Pim-1 signaling axis is triggered following cardiomyopathic injury in vivo, 2) ?5?1-integrin receptor activation by Fn induces immediate early stress responses, survival, and proliferation via FAK-Pim-1 signaling in CPCs, 3) Robust and persistent CPC- dependent regeneration is mediated by overexpression of a collagen binding Fn fragment delivered by cardiotropic AAV9 vector. The significance of these studies is to define beneficial aspects of the endogenous repair to injury response. The long term goal will be to transfer the Fn fragment expressing AAV9 regimen into human disease establishing an innovative therapeutic concept for regenerative medicine.