Effects of Oxidized Low-density Lipoprotein on Bone Marrow Stem Cell

氧化低密度脂蛋白对骨髓干细胞的影响

• 批准号: 7890139
• 负责人: ZHENGUO LIU
• 金额: $ 38.13万
• 依托单位: OHIO STATE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-06-01 至 2015-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7890139
• 关键词: 1-Phosphatidylinositol 3-Kinase; Adhesions; Adult; Animals; Area; Arterial Fatty Streak; Atherogenic Diet; Atherosclerosis; Be++ element; Beryllium; Blood Vessels; Bone Marrow; Bone Marrow Stem Cell; Bone Marrow Transplantation; C57BL/6 Mouse; Cardiovascular Diseases; Cardiovascular system; Cell Count; Cell Proliferation; Cell physiology; Cells; Collaborations; Complex; Data; Development; Electron Spin Resonance Spectroscopy; Extracellular Signal Regulated Kinases; Functional disorder; Generations; Genes; Hyperlipidemia; In Vitro; Infusion procedures; Injury; Knock-out; Knowledge; Label; Low Density Lipoprotein Receptor; Marrow; Measures; Mitogen-Activated Protein Kinases; Modeling; Multipotent Stem Cells; Mus; Natural regeneration; Oxidation-Reduction; Oxidative Stress; Pathogenesis; Pathway interactions; Patients; Phosphorylation; Play; Population; Protein-Serine-Threonine Kinases; Research; Role; Signal Transduction; Stem cells; Testing; Tissues; Transfection; Wild Type Mouse; base; design; in vivo; injured; intravenous administration; low density lipoprotein inhibitor; male; migration; monolayer; neointima formation; novel; novel strategies; overexpression; oxidized low density lipoprotein; peripheral blood; prevent; public health relevance; repaired; research study; stem cell population; vector

DESCRIPTION (provided by applicant): Adult bone marrow multipotent progenitor cells (MAPCs) are one of well characterized bone marrow- derived stem cells. Our initial studies show that oxidized low-density lipoprotein (ox-LDL) significantly inhibits the proliferation of murine MAPCs and their endothelial differentiation in association with a selective and dramatic reduction of serine/threonine kinase Akt (Akt) phosphorylation. It is well known that the number and function of endothelial progenitor cells (EPCs) are markedly reduced in the patients with hyperlipidemia. The present study will test the hypothesis that ox-LDL reduces stem cell population within the bone marrow, and impairs their differentiation into EPCs due to interrupted Akt signaling. The specific aims are: 1). To evaluate the effect of ox-LDL on the population of stem cells within bone marrow and the underlying mechanisms; and 2). To investigate the role of ox-LDL in the differentiation of MAPCs into EPCs and the underlying mechanisms. Murine MAPCs will be isolated, cultured and quantitatively analyzed from both hyperlipidemic male LDL receptor knock out (LDLR-/-) mice (with atherogenic diet) and ox-LDL-infused wild-type (WT) normal C57BL/6 mice. The number of MAPCs within the bone marrow, Oct-4 expression, and their proliferation and differentiation into EPCs will be evaluated. To further test the hypothesis, bone marrow transplantation with eGFP- labeled MAPCs will be performed in LDLR(-/-) mice and ox-LDL-infused WT mice. The eGFP-positive EPCs will be isolated and quantitatively analyzed from the animals for EPC number and function. If the hypothesis is true, it is expected that the population and function of MAPCs within the bone marrow and EPCs in the bone marrow and peripheral blood will be significantly decreased in ox-LDL-infused animals and in hyperlipidemic LDLR(-/-) mice. It is also anticipated that Oct-4 expression, cell proliferation, and endothelial differentiation of the MAPCs isolated from the hyperlipidemic LDLR(-/-) mice and ox-LDL- infused WT mice will be significantly decreased along with a significant reduction in Akt phosphorylation in MAPCs. Conversely, the number and function of eGFP-positive MAPCs within the bone marrow and EPCs in the bone marrow and peripheral blood will increase significantly in the animals (both hyperlipidemic mice and ox-LDL-infused WT mice) that receive bone marrow transplantation with eGFP- positive MAPCs transfected with retroviral Akt1 vectors, and stably over-expressing active Akt. In addition, overexpression of active Akt will decrease atherosclerotic plaque formation in hyperlipidemic mice, and enhance vascular repair with reduced neointima formation in ox-LDL-infused mice. The data from this study will provide novel information on the mechanisms for the development of atherosclerosis in patients with hyperlipidemia, and help explore new approaches to preventing and treating cardiovascular diseases. PUBLIC HEALTH RELEVANCE: Endothelial progenitor cells (EPCs) originate from the bone marrow stem cells. These cells play a critical role in maintaining the structural and functional integrity of the endothelial monolayer in blood vessels. The number of EPCs is markedly reduced along with significantly decreased EPC function in hyperlipidemic patients. Oxidized low-density lipoprotein (ox-LDL) is a key element that is associated with cardiovascular diseases in hyperlipidemic patients. This study will investigate how ox-LDL disrupts the generation and function of EPCs in the bone marrow.

描述（由申请人提供）：成年骨髓多能祖细胞（MAPC）是表征良好的骨髓衍生的干细胞之一。我们的初步研究表明，氧化的低密度脂蛋白（OX-LDL）显着抑制鼠MAPC的增殖及其内皮分化，以及丝氨酸/苏氨酸激酶AKT（AKT）磷酸化的选择性和急剧减少。众所周知，高脂血症患者的内皮祖细胞（EPC）的数量和功能显着降低。本研究将检验以下假设：OX-LDL会减少骨髓内的干细胞群体，并损害其由于AKT信号中断而损害其为EPC的分化。具体目的是：1）。评估OX-LDL对骨髓和潜在机制中干细胞种群的影响；和2）。研究OX-LDL在MAPC分化为EPC和潜在机制中的作用。将从高脂雄性LDL受体敲除（LDLR - / - ）小鼠（含有动脉粥样硬化的饮食）和OX- LDL融合的野生型（WT）正常C57BL/6小鼠中分离出鼠MAPC。将评估骨髓中的MAPC数量，OCT-4表达及其扩散和分化为EPC。为了进一步检验该假设，将在LDLR（ - / - ）小鼠和ox-LDL注入的WT小鼠中使用具有EGFP标记的MAPC的骨髓移植。 EGFP阳性EPC将被分离，并从动物中进行定量分析EPC的数量和功能。如果该假设是正确的，则可以预期，骨髓中MAPC的种群和功能在骨髓中的EPC和EPCS和外周血中的EPC在OX- LDL的动物和高脂症LDLR（ - / - ）小鼠中的种群和功能将显着降低。还可以预见，从高脂症状LDLR（ - / - ）小鼠和OX-LDL-注入的WT小鼠中分离出的MAPC的OCT-4表达，细胞增殖和内皮分化将显着降低，并且MAPC中AKT磷酸化的显着降低。 Conversely, the number and function of eGFP-positive MAPCs within the bone marrow and EPCs in the bone marrow and peripheral blood will increase significantly in the animals (both hyperlipidemic mice and ox-LDL-infused WT mice) that receive bone marrow transplantation with eGFP- positive MAPCs transfected with retroviral Akt1 vectors, and stably over-expressing active Akt.另外，主动AKT的过表达将减少高脂血症小鼠中的动脉粥样硬化斑块形成，并在OX-LDL注入的小鼠中增强血管修复。这项研究的数据将提供有关高脂血症患者动脉粥样硬化的机制的新信息，并有助于探索预防和治疗心血管疾病的新方法。 公共卫生相关性：内皮祖细胞（EPC）起源于骨髓干细胞。这些细胞在维持血管内皮单层的结构和功能完整性方面起着关键作用。高脂血症患者的EPC数量显着减少，EPC功能显着降低。氧化的低密度脂蛋白（OX-LDL）是与高脂血症患者心血管疾病有关的关键元素。这项研究将研究OX-LDL如何破坏EPC在骨髓中的产生和功能。