Identification of Novel Endothelial Progenitor Cells

描述(由申请人提供)：使用骨髓(BM)来源的干细胞或祖细胞进行细胞治疗已成为修复或再生缺血性心血管疾病的一种有前途的方式。许多实验研究表明，骨髓来源的细胞如内皮祖细胞、间充质干细胞或类似的多能干细胞在修复或再生缺血性心血管疾病方面是有效的。与此同时，关于骨髓来源的干细胞或祖细胞的(反式)分化潜力一直存在争议。现在更广泛地接受的是，骨髓来源的内皮祖细胞的治疗作用主要是通过旁分泌或体液效应等非转分化效应来实现的。此外，人类新类型内皮祖细胞的培养鉴定使这一领域变得更加复杂。然而，还没有人报道一个特定的标志物来前瞻性地分离BM来源的EPC。在过去的几年里，我的实验室一直在研究EPC生物学中最重要的两个主题：转分化和心血管疾病的治疗效果。在这项研究中，我们发现大约25%-30%的骨髓单个核细胞表达CD31表位，这些骨髓来源的CD31+细胞(BM-CD31+)具有高血管生成活性，包括血管生成(具有向内皮细胞分化的潜能)细胞群(S)。我们还发现，这些CD31+细胞对治疗肢体缺血非常有效。因此，在这项建议中，我们建议通过使用一组具有真正的(反式)分化潜力和/或血管生成/旁分泌活性的候选标记来细分CD31+细胞来进一步鉴定新的内皮祖细胞。在具体目标1中，我们将探索鉴定CD31+组分中含有的具有血管生成潜力的新型内皮祖细胞。在具体目标2中，我们将研究这些CD31亚群的血管生成或旁分泌特性。我们预计，这项提案中概述的实验结果将为新型内皮祖细胞修复缺血性心血管疾病的身份和治疗潜力提供新的见解。公共卫生相关性：来自骨髓的内皮祖细胞(EPC)已显示出修复或再生缺血心血管组织的潜力；然而，关于其身份和潜在的治疗机制仍存在疑问。我们最近发现了一组新的骨髓来源的CD31阳性细胞，它们具有血管生成和真正的血管生成特性。在这项建议中，我们建议通过缩小CD31亚组分的范围来鉴定具有血管生成和/或血管生成特性的真正的EPC。

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.