Preconditioning and re-programming of stem cells for cardiac repair

描述（由申请人提供）：使用具有肌生成和血管生成潜能的干细胞或细胞因子诱导的骨髓细胞（BMCs）动员到损伤部位的心脏细胞治疗已显示出前景。同样，缺血预处理和药理学预处理也具有心脏保护作用。这些治疗方式已被用于促进心肌再生和逆转心肌梗死（MI）后有害的血流动力学影响。为了达到这些效果，本研究涉及骨髓基质与骨骼肌母细胞（SkMs）的移植，后者将主要作为治疗基因的载体。我们的主要假设是，移植前对细胞进行预处理和重编程可以提高它们的存活、植入和心脏修复的功效。我们研究的主要目的是；目的1)对供体细胞进行预处理，提高其移植后的存活率。我们假设通过预处理模拟物处理细胞可能通过刺激细胞存活信号增强其对缺血的耐受性。预调节（PC）细胞也会表现出旁分泌效应，这将提高宿主心肌细胞在梗死心脏中的存活率。Aim-2)心肌内递送非病毒转染的过表达SDF-11的SkMs，同时进行短暂细胞因子治疗，以动员bmc，改善心功能。我们假设心脏中升高的SDF-11水平会吸引循环中的CXCR4+ bmc参与缺血心脏血管生成的修复过程，而细胞因子治疗后BM中CXCR4+ bmc的分泌会明显增加。目的3：在移植前激活供体SkMs的细胞保护调控通路。考虑到Akt和Bcl-2在血管生成素-1 (ang1)/Tie-2信号通路下游的细胞存活和血管生成中的关键作用，我们假设移植共过表达Ang-1和Akt或Bcl-2的SkMs将提高细胞存活，增强血管生成，改善心功能。Aim-4将重点关注供体细胞的体外重编程，通过与心肌细胞共培养实现移植后心脏表型的定向分化。共培养的细胞在移植后具有较好的植入和转分化能力。综上所述，我们在移植前对供体细胞进行预处理和重编程的联合治疗方法有望为缺血性心肌损伤的治疗提供更好的预后。

DESCRIPTION (provided by applicant): Heart cell therapy using stem cells with myogenic and angiogenic potential or cytokine induced mobilization of bone marrow cells (BMCs) to the site of injury has shown promise. Similarly, ischemic and pharmacological preconditioning has cardioprotective effects. These therapeutic modalities have been adopted to promote de novo myocardial regeneration and reversal of deleterious hemodynamic effects after myocardial infarction (MI). In order to achieve these effects the present study involves transplantation of BMCs together with skeletal myoblasts (SkMs) which will serve mainly as carries of therapeutic genes. Our main hypothesis is that preconditioning and re-programming of cells prior to transplantation would enhance their survival, engraftment and efficacy for cardiac repair. The main aims of our study are; Aim-1) Preconditioning of donor cells for their enhanced survival after transplantation. We posit that treatment of cells by preconditioning mimetics may enhance their tolerance to ischemia via stimulation of cell survival signaling. The preconditioned (PC) cells will also exhibit paracrine effects which will give enhanced host myocyte survival in the infarcted heart. Aim-2) Intramyocardial delivery of non-virally transfected SkMs overexpressing SDF-11 along with transient cytokine therapy for BMCs mobilization for improved heart function. We hypothesized that the elevated SDF-11 levels in the heart will attract circulating CXCR4+ BMCs, egress of which from BM will be distinctly increased after cytokine therapy, to participate in the repair process by angiomyogenesis in the ischemic heart. Aim-3: To activate cytoprotective regulatory pathways in donor SkMs before transplantation. Considering a critical role for Akt and Bcl-2 in cell survival and angiogenesis downstream of angiopoietin-1 (Ang-1)/Tie-2 signaling pathway, we hypothesize that transplantation of SkMs co-overexpressing Ang-1 and Akt or Bcl-2 will give increased cell survival, enhanced angiogenesis, and improved cardiac function. Aim-4 will focus on in vitro re-programming of donor cells for directed differentiation via co-culture with cardiomyocytes to adopt cardiac phenotype after transplantation. The co-culture derived cells will show better engraftment and transdifferentiation after transplantation. Put together, our combined therapeutic approach for preconditioning and re-programming of donor cells before transplantation is expected to give better prognosis in the treatment of ischemically injured myocardium.