Factors Responsible for Cardiac Preservation Conferred by Adult Marrow Stem Cells

描述(申请人提供)：成人骨髓间充质干细胞(MSCs)可促进心肌梗死(MI)动物心脏功能的恢复。在几个国家，这些细胞已经被用于心肌梗塞患者，据报道有有益的效果。尽管应用MSC很有效，但大多数研究表明，很少有细胞能长期植入，而且只有一部分存活的细胞似乎能分化为成熟的心脏表型。在动物体内，将浓缩的条件培养液注射到心肌中似乎具有与直接注射细胞相似的效果，这意味着细胞分泌的因子构成了益处的主要基础。我们的初步数据表明，当静脉注射(IV)给心肌梗塞动物时，非造血型人骨髓干细胞可以发挥心脏保护和修复作用。此外，我们还发现，以混合MSCs或经p75低亲和力神经生长因子受体(p75LNGFR；p75MSCs)磁选分离的标准化MSCs为条件的无血清培养液可以通过激活转录因子STAT3来支持成人心脏干/祖细胞的生长和存活。由于MSCs是从不同种类的贴壁细胞混合物中制备的，因此希望有一种标准化的祖细胞群体分离程序，以预测地提供心脏保护和/或修复。我们最近通过特定的细胞表面表位从骨髓的总单个核细胞中分离出非造血干细胞亚群。根据它们分泌蛋白的表达谱，它们可能特别适合心脏保存。比较其中一个亚群(P75MSCs)和混合贴壁MSCs的有效性，我们将确定静脉或肌肉注射非自体干细胞是否可以用于提供基于旁分泌的心脏细胞治疗。我们将确定干细胞分泌的有效因子，并确定其作用机制是通过抑制凋亡或坏死来保护现有的心肌细胞，还是促进内源性心肌干细胞的增殖和存活。 具体目标 1.鉴定具有心脏保护作用的人骨髓干细胞亚群，并确定修复免疫缺陷小鼠心肌梗死后心功能所需的生长条件和给药时机。 2.检测品系不合的小鼠骨髓干细胞静脉或肌肉注射对免疫活性小鼠心肌梗死后的心脏保护或恢复的能力。 3.鉴定干细胞分泌的维持心功能的特定因子。

DESCRIPTION (provided by applicant): The adult bone marrow non-hematopoietic stem cells known as mesenchymal stem cells (MSCs) promote functional cardiac recovery in animals with myocardial infarction (MI). In several countries these cells have been administered to patients with MI with reported beneficial effects. Despite the efficacy of MSC administration, most studies have shown that few of the cells engraft long-term and that only a portion of the surviving cells appear to differentiate to a mature cardiac phenotype. In animals injection of concentrated conditioned medium into cardiac muscle appears to have effects similar to those of direct injection of cells, implying that secreted factors from the cells comprise the principle basis for the benefits. Our preliminary data demonstrate that non-hematopoietic human bone marrow stem cells can exert cardiac protective and reparative effects when delivered intravenously (IV) to animals with MI. Furthermore, we show that serum-free medium conditioned by mixed MSCs or by standardized MSCs isolated by magnetic sorting for the p75 low affinity nerve growth factor receptor (p75LNGFR; p75MSCs) can support the growth and survival of adult cardiac stem/progenitor cells through activation of the transcription factor STAT3. Because MSCs are prepared from a heterogeneous mixture of adherent cells, it is desirable to have a standardized isolation procedure for a population of progenitor cells that predictively imparts cardiac protection and/or repair. We have recently isolated sub-populations of non-hematopoietic stem cells from the total mononuclear cells of bone marrow by specific cell surface epitopes. They may be particularly well-suited for cardiac preservation based on their expression profiles of secreted proteins. Comparing the effectiveness of one of these sub-populations (p75MSCs) to mixed adherent MSCs, we will determine whether intravenous or intramuscular administration of non-autologous stem cells can be used to provide paracrine-based cardiac cell therapy. We will identify the factors secreted by the stem cells that are effective and determine whether the mechanism of action is sparing of existing cardiomyocytes by inhibition of apoptosis or necrosis or augmenting the proliferation and survival of endogenous cardiac stem cells. SPECIFIC AIMS 1. To identify a cardioprotective sub-population of human bone marrow stem cells and determine the growth conditions and timing of administration necessary to rescue cardiac function after MI in immunodeficient mice. 2. To determine the ability of strain-mismatched murine bone marrow stem cells delivered intravenously or intramuscularly to promote cardiac protection or recovery after MI in immunocompetent mice. 3. To identify the specific factors secreted by the stem cells that preserve cardiac function.