Ambient fine particulate matter and bone marrow stem cells

 描述（由申请人提供）：环境细颗粒物（PM）是空气污染的关键成分，与显著的死亡率相关。PM暴露后的大多数死亡与心血管疾病有关。内皮祖细胞（EPCs）是维持血管完整性和功能的重要细胞，骨髓是其主要来源之一。PM暴露对心血管系统有多种不良影响，并显著降低EPCs的数量和功能。然而，PM暴露诱导EPCs损伤的机制尚未完全清楚。最近，我们观察到，PM暴露显着降低循环EPCs的水平和骨髓内的骨髓干细胞（BMSCs）的人口与活性氧（ROS）的形成水平增加在小鼠中。当ROS的产生被阻断时，PM诱导的EPCs和BMSCs的减少被有效地阻止。本项目旨在验证“PM暴露通过氧化应激介导的骨髓中BMSC数量减少以及BMSC产生EPCs减少来减少EPCs的数量和功能”的假设。有两个具体目标：1）：确定PM暴露对BMSC及其内皮分化的影响;和2）：确定氧化应激在介导PM暴露对BMSC及其分化为EPCs的影响中的作用。我们将证明PM暴露导致骨髓中BMSC的数量和功能显著减少。我们将确定BMSC数量的减少是由于细胞凋亡增加还是增殖减少。我们还将使用骨髓移植（BMT）与eGFP阳性BMSC进行实验，以确定PM暴露是否会损害BMScs分化为EPC，这可能导致PM暴露环境中EPC数量和功能减少。为了确定PM暴露是否会对BMSC产生与慢性空气污染相似的影响，将使用暴露于空气污染长达6个月的小鼠重复实验。我们将测试PM诱导的ROS产生是否会导致BMSC的数量和功能减少，通过使用抗氧化剂N-乙酰半胱氨酸或伴随的人铜/锌超氧化物歧化酶（SOD）1，细胞外SOD 3和谷胱甘肽过氧化物酶的抗氧化酶网络过表达来阻断ROS产生，减少ROS的形成。我们还将使用具有eGFP-BMSCs的BMT模型来确定PM诱导的氧化应激是否在BMSCs向EPCs的分化中起关键作用。将进行实验以评估ROS在暴露于空气污染长达6个月的小鼠中的BMSC群体及其向EPCs分化中的作用。这项研究的数据将为PM暴露和空气污染患者心血管疾病的发生机制提供重要和新颖的信息，并有助于探索预防和治疗与PM暴露相关的心血管疾病的新方法。1

 DESCRIPTION (provided by applicant): Ambient fine particulate matter (PM) is the key components for air pollution, and associated with significant mortality. The majority of the mortality following PM exposure is related to cardiovascular diseases. Endothelial progenitor cells (EPCs) are critical to maintaining the integrity and function of blood vessels with bone marrow as one of their main sources. PM exposure exhibits various deleterious effects on cardiovascular system, and significantly decreases the number and function of EPCs. However, the mechanism(s) for PM exposure- induced impairment of EPCs has not been fully understood. Recently, we observed that PM exposure significantly decreased the level of circulating EPCs s and the population of bone marrow stem cells (BMSCs) within the bone marrow in association with increased level of reactive oxygen species (ROS) formation in mice. When ROS production was blocked, PM-induced reduction of EPCs and BMSCs was effectively prevented. The present project was proposed to test the hypothesis that "PM exposure reduces the number and function of EPCs through oxidative stress-mediated reduction of BMSC population in bone marrow with reduced generation of EPCs from BMSCs". There are two specific aims: 1): to determine the effect of PM exposure on BMSCs and their endothelial differentiation; and 2): to define the role of oxidative stress in mediating the effect of PM exposure on BMSCs and their differentiation into EPCs. We will demonstrate that PM exposure leads to a significant reduction in the number and function of BMSCs in the bone marrow. We will determine if the decrease in the number of BMSCs is due to increased apoptosis or decreased proliferation. We will also conduct experiments using bone marrow transplantation (BMT) with eGFP-positive BMSCs to determine if PM exposure impairs the differentiation of BMScs into EPCs that may contribute to decreased number and function of EPCs in the setting of PM exposure. To determine if PM exposure could produce a similar effect on BMSCs as chronic air pollution, the experiments will be repeated using mice exposed to air pollution for up to 6 months. We will test whether PM-induced ROS production causes decreased number and function of BMSCs by blocking ROS production using either antioxidant N-acetylcysteine or concomitant overexpression of an antioxidant enzyme network of human copper/zinc superoxide dismutase (SOD) 1, extracellular SOD3, and glutathione peroxidase with decreased ROS formation. We will also use BMT model with eGFP-BMSCs to determine if PM-induced oxidative stress plays a critical role in the differentiation of BMSCs into EPCs. Experiments will be conducted to evaluate the role of ROS in the population of BMSCs and their differentiation into EPCs in the mice exposed to air pollution for up to 6 months. The data from this study will provide important and novel information on the mechanisms for the development of cardiovascular diseases in patients with PM exposure and air pollution, and help explore new approaches to preventing and treating cardiovascular diseases related to PM exposure. 1