Restoration of myocardial reparative function of diabetic progenitor cells by epigenetic modulation

在缺血性损伤后缺乏有效的内源性修复机制的情况下，出现了基于细胞的治疗方法 作为缺血组织修复的潜在新治疗方法。在对假定的骨骼进行初步鉴定后 骨髓来源的内皮祖细胞（EPC）及其促进心脏和严重肢体缺血的潜力 新血管形成和减轻缺血性损伤，十多年的密集临床前研究，导致了 基于BM祖细胞/EPC的临床试验。然而，尽管早期的热情，细胞为基础的疗法产生了温和的 临床结果。基于细胞的治疗的适度临床结果可能反映了已知的细胞功能障碍， 在从糖尿病动物以及患者获得的EPC/祖细胞中发生。令人信服的证据表明， EPCs功能障碍代表了糖尿病血管修复和血管生成受损的机制， 导致血管功能障碍因此，了解糖尿病诱导的EPC功能障碍的分子基础 并可能逆转EPC功能障碍可能代表了一种增强基于细胞的治疗方法的策略， 糖尿病患者的心肌/缺血肢体修复。越来越多的证据表明， 潜在的高血糖记忆和EPC功能障碍可能涉及表观遗传机制， 表观遗传抑制标记的血管基因，导致其表观遗传沉默。此外，由于高血糖 记忆是通过细胞分裂遗传的，糖尿病EPCs中改变的表观遗传模式可以传递给 子细胞了解糖尿病患者EPC功能障碍的表观遗传学基础和糖尿病患者的表观遗传学重编程 因此，糖尿病EPCs对于糖尿病患者的基于细胞的治疗是至关重要的。所以我们的 核心假设是糖尿病EPCs中的表观遗传抑制标记使其功能障碍和表观遗传 靶向这些抑制性标记的修饰剂可以将糖尿病EPCs重编程为功能更强的修复性EPCs。 表型。该项目旨在详细研究，表型，表观遗传和分子特征， 来自糖尿病小鼠的重编程糖尿病EPCs以及来自糖尿病小鼠的人CD 34+造血干细胞 患者及其外泌体衍生物，并测试这些重编程的 糖尿病EPCs在MI和后肢缺血的生理相关模型中。这一总体目标将通过以下方式实现： 进行根据以下三个具体目标组织的实验：1）评价表型稳定性， 表观遗传重编程的糖尿病EPCs的修复潜力; 2）确定表观遗传重编程的糖尿病EPCs的特异性表观遗传重编程的修复潜力。 在重编程EPCs中的修饰，并建立HDAC 1和G9 a甲基转移酶在重编程中的作用 过程和3）建立表观遗传重编程拯救人CD 34+细胞的功能和修复缺陷 2型糖尿病患者的干细胞。

In the absence of effective endogenous repair mechanisms after ischemic injury, cell-based therapies have emerged as a potential novel therapeutic approach in ischemic tissue repair. After the initial characterization of putative bone marrow-derived endothelial progenitor cells (EPC) and their potential to promote cardiac and critical limb ischemia neovascularization and to attenuate ischemic injury, more than a decade of intense preclinical research, led to the BM progenitors/EPC-based clinical trials. However, despite early enthusiasm, cell based therapies yielded modest clinical results. Modest clinical outcomes of cell-based therapies may reflect the cellular dysfunction that is known to ensue in EPC/progenitor cells obtained from diabetic animals as well as patients. Compelling evidence indicates that EPCs dysfunction represents a mechanism for impaired vascular repair and angiogenesis in diabetes, subsequently leading to vascular dysfunction. Therefore, understanding the molecular basis of diabetes-induced EPC dysfunction and potentially reversing EPC dysfunction may represent a strategy to enhance cell-based therapeutics for myocardial/ischemic limb repair in diabetic patients. Increasing evidence also indicates that the mechanism underlying hyperglycemic memory and EPC dysfunction may involve epigenetic mechanisms involving enhanced epigenetic repressive marks on vascular genes leading to their epigenetic silencing. Moreover, since hyperglycemic memory is inherited through cell division, and altered epigenetic patterns in diabetic EPCs can be transmitted to daughter cells. Understanding the epigenetic basis of EPC dysfunction in diabetics and epigenetic reprogramming of diabetic EPCs, is therefore, of paramount importance for cell based therapies in diabetic patients. Therefore, our central hypothesis is that epigenetic repressive marks in diabetic EPCs render them dysfunctional and epigenetic modifying agents targeting those repressive marks can reprogram diabetic EPCs to a more functional and reparative phenotype. This project aims to study, in detail, phenotypic, epigenetic and molecular characterization of reprogrammed diabetic EPCs from diabetic mice as well as human CD34+ hematopoietic stem cells from diabetic patients and their exosome derivatives and test the ischemic myocardial repair capacity of these reprogrammed diabetic EPCs in physiologically relevant model of MI and hind limb ischemia. This overall aim will be achieved by conducting experiments organized under the following three specific aims: 1) To evaluate phenotypic stability and reparative potential of epigenetically reprogrammed diabetic EPCs; 2) To determine the specific epigenetic modifications in reprogrammed EPCs and establish a role of HDAC1 and G9a methytransferase in reprogramming process and 3) To establish epigenetic reprogramming rescues functional and reparative deficits in human CD34+ stem cells from patients with Type 2 diabetes.