Identification of Novel Endothelial Progenitor Cells

描述（由申请人提供）：使用骨髓（BM）源性干细胞或祖细胞的细胞疗法已成为修复或再生缺血性心血管疾病的有前景的模式。许多实验研究已经证明，骨髓来源的细胞，如内皮祖细胞（EPCs），间充质干细胞（MSCs）或类似的多能干细胞是有效的修复或再生缺血性心血管疾病。与此同时，关于骨髓源性干细胞或祖细胞的（转）分化潜力一直存在争议。现在更广泛地接受的是，BM衍生的EPCs的治疗作用主要是通过非转分化效应如旁分泌或体液效应介导的。此外，人类新型EPCs的培养鉴定使这一领域变得更加复杂。然而，还没有人报道一种特异性标记物来前瞻性地分离来自BM的EPCs。在过去的几年里，我的实验室一直在研究EPC生物学中两个最重要的课题：转分化和心血管疾病的治疗作用。在这项研究中，我们发现大约25-30%的BM单核细胞表达CD 31表位，并且这些BM衍生的CD 31阳性（BM-CD 31+）细胞具有高血管生成活性，并且包括血管生成（具有分化为内皮细胞的潜力）细胞群。我们还发现，这些CD 31+细胞对治疗肢体缺血非常有效。因此，在该提议中，我们提出通过使用一组候选标志物亚分级⑶ 31+细胞来进一步鉴定新的EPC，所述候选标志物具有真正的（反式）分化潜力和/或血管生成/旁分泌活性。在具体目标1中，我们将探索鉴定CD 31+组分中含有的具有血管生成潜力的新型EPC。在特定目标2中，我们将研究这些CD 31亚群的血管生成或旁分泌特性。我们预计，本提案中概述的实验结果将产生新的见解的身份和治疗潜力的新型EPCs修复缺血性心血管疾病。公共卫生相关性：骨髓来源的内皮祖细胞（EPCs）具有修复或再生缺血性心血管组织的潜力，但其特性和潜在的治疗机制仍存在争议。我们最近发现了一种新的骨髓来源的CD 31阳性细胞，具有血管生成和真正的血管生成特性。在这个建议中，我们建议通过缩小CD 31亚组分来识别具有血管生成和/或血管生成特性的真正的EPCs。

DESCRIPTION (provided by applicant): Cell therapy using bone marrow (BM)-derived stem or progenitor cells has emerged as a promising modality for repairing or regenerating ischemic cardiovascular diseases. Many experimental studies have demonstrated that BM-derived cells such as endothelial progenitor cells (EPCs), mesenchymal stem cells (MSCs) or similar multipotent stem cells are effective to repair or regenerate ischemic cardiovascular diseases. In the meantime, there has been an ongoing controversy regarding the (trans)differentiation potential of BM-derived stem or progenitor cells. It is now more widely accepted that the therapeutic effects of BM-derived EPCs are mediated mainly through non-transdifferentiation effects such as paracrine or humoral effects. Furthermore, the culture-identification of newer types of EPCs in human has rendered this field more complicated. However, no one has yet reported a specific marker to prospectively isolate EPCs derived from BM. Over the last few years, my lab has been investigating two most important topics in EPC biology: transdifferentiation and therapeutic effects in cardiovascular diseases. During this research, we have found that approximately 25-30% of BM mononuclear cells express the CD31 epitope, and these BM-derived CD31-positive (BM-CD31+) cells have high angiogenic activity and include vasculogenic (having the potential to differentiate into endothelial cells) cell population(s). We have also found that these CD31+ cells are highly effective for treating limb ischemia. Accordingly, in this proposal, we propose to further identify novel EPCs by sub- fractioning CD31+ cells using a panel of candidate markers, which have genuine (trans)differentiation potential and/or angiogenic/paracrine activities. In Specific aim 1, we will explore identification of novel EPCs contained in CD31+ fractions which possess vasculogenic potential. In Specific Aim 2, we will the angiogenic or paracrine properties of these CD31 sub-populations. We anticipate that the results of the experiments outlined in this proposal will yield new insight into the identity and therapeutic potency of novel EPCs for repairing ischemic cardiovascular diseases. PUBLIC HEALTH RELEVANCE: Endothelial progenitor cells (EPCs) from bone marrow have shown the potential to repair or regenerate ischemic cardiovascular tissues; however, there still remain concerns regarding the identity and underlying therapeutic mechanisms. We recently identified a novel population of bone marrow-derived CD31 positive cells which have angiogenic and genuine vasculogenic properties. In this proposal, we propose to identify genuine EPCs which have vasculogenic and/or angiogenic properties by narrow downing the CD31 subfractions.