Oxidized Low Density Lipoprotein Immune Complexes in Atherosclerosis

动脉粥样硬化中的氧化低密度脂蛋白免疫复合物

• 批准号: 8909698
• 负责人: Jillian Patricia Rhoads
• 金额: $ 2.78万
• 依托单位: VANDERBILT UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-05-01 至 2017-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8909698
• 关键词: Accounting; Adoptive Transfer; American; Antibodies; Antibody Formation; Antigen-Antibody Complex; Antigen-Presenting Cells; Arteries; Atherosclerosis; Binding; Blood Vessels; Bone Marrow; Bone Marrow Transplantation; C57BL/6 Mouse; CD36 gene; Cardiovascular Diseases; Cardiovascular system; Cell Line; Cell Surface Receptors; Cells; Cessation of life; Cholesterol; Chronic; Coculture Techniques; Data; Dendritic Cells; Dendritic cell activation; Development; Disease; Disease Progression; Fc Receptor; Flow Cytometry; Generations; Goals; ITGAX gene; Immune response; Immune system; Immunity; Immunology; In Vitro; Inflammation; Inflammatory; Knock-out; Knockout Mice; Knowledge; Laboratories; Leukocytes; Ligation; Low-Density Lipoproteins; Measures; Mediating; Modern Medicine; Mus; Outcome; Pathogenesis; Play; Population; Process; Production; Publishing; Regulation; Reporting; Role; Severity of illness; Sterility; T cell response; T-Lymphocyte; TLR4 gene; Testing; Therapeutic Intervention; Tissues; United States; adaptive immunity; cytokine; in vivo; macrophage; mortality; oxidized low density lipoprotein; public health relevance; receptor; therapeutic target

 DESCRIPTION (provided by applicant): Cardiovascular disease (CVD) is the number one cause of mortality in the United States. The most common form of CVD is atherosclerosis which characterized by chronic inflammation resulting in the formation of plaques in the arteries. Inflammation is initiated by the sequestration of low-density lipoproteins (LDL) in the vessel wall where they become oxidized (ox-LDL) and cause damage to local cells. This results in the recruitment of antigen presenting cells (APCs) including dendritic cells (DCs). While oxLDL antibody titers and resulting immune complexes (oxLDL-ICs) correlate with disease severity, it is unknown if oxLDL-ICs play a role in disease pathogenesis. Studies in macrophage cell lines have shown increased cellular activation following oxLDL-IC treatment. However, the role of DCs in this process is largely unstudied, and reports regarding the in vivo relevance are lacking. Preliminary data from our lab show that oxLDL-ICs cause increased DC activation as measured by expression of activation markers and secretion of pro-inflammatory cytokines. These in vitro studies suggest an atherogenic role for oxLDL-ICs. Given the potent ability of DCs to elicit a downstream immune response, understanding oxLDL-IC mediated DC activation will fill a critical gap in our knowledge of CVD pathogenesis and provide new avenues for therapeutic intervention. We propose two aims to determine the effects of oxLDL-ICs on DCs and the implication of these effects on atherosclerotic outcomes. In aim 1, we will determine the mechanism by which oxLDL-ICs modulate DC activation and cytokine production. It is likely that oxLDL-ICs activate DCs through binding and internalization by Fc receptors (FcRs), which recognize the Fc portion of ICs and can be found on several leukocyte populations including DCs. However, given that oxLDL is known to bind other cell surface receptors including TLR4 and CD36, we believe that oxLDL-ICs may increase inflammation by concomitant interaction with several cell surface receptors. We will test this hypothesis by treating bone marrow derived DCs from wild type (C57BL/6) mice and receptor- specific knock-out mice with oxLDL or oxLDL-ICs. Activation will be measured by flow cytometry and cytokine production. BMDC will also be co-cultured with T cells to determine their ability to elicit an immune response. In aim 2, we will determine the effects of dendritic cell specific FcR on atherosclerosis. Given the robust capacity of DCs to activate and differentiate naïve T cells and thus control downstream immune responses, DC FcRs are likely to be important in mediating atherosclerotic outcomes. To identify how DC FcR mediate atherosclerosis, we will perform an adoptive transfer of wild type or FcR-/- DC into LDLr-/- mice. Additionally, we will perform a bone marrow transplant of the progeny from FcRflox/flox mice crossed with CD11c Cre+ mice to obtain DC specific FcR knockouts into LDLr-/- mice. Collectively, the proposed studies will identify a role for oxLDL-ICs in atherosclerosis.

 描述（由申请人提供）：心血管疾病（CVD）是美国的头号死亡原因。最常见的CVD形式是动脉粥样硬化，其特征在于慢性炎症导致动脉中斑块的形成。炎症是由低密度脂蛋白（LDL）在血管壁中的隔离引发的 在那里它们被氧化（ox-LDL）并对局部细胞造成损伤。这导致包括树突细胞（DC）的抗原呈递细胞（APC）的募集。虽然oxLDL抗体滴度和产生的免疫复合物（oxLDL-IC）与疾病的严重程度相关，但尚不清楚oxLDL-IC是否在疾病发病机制中发挥作用。巨噬细胞系研究显示oxLDL-IC处理后细胞活化增加。然而，DC在这一过程中的作用在很大程度上是未研究的，并且缺乏关于体内相关性的报道。我们实验室的初步数据显示，oxLDL-IC引起DC活化增加，如通过活化标志物的表达和促炎细胞因子的分泌所测量的。这些体外研究表明oxLDL-IC具有致动脉粥样硬化作用。鉴于DC引发下游免疫应答的强大能力，理解oxLDL-IC介导的DC活化将填补我们对CVD发病机制的认识中的关键空白，并为治疗干预提供新的途径。我们提出了两个目标，以确定oxLDL-IC对DC的影响，以及这些影响对动脉粥样硬化结果的影响。在目标1中，我们将确定oxLDL-IC调节DC活化和细胞因子产生的机制。oxLDL-IC可能通过Fc β受体（Fc β R）的结合和内化激活DC，Fc β R识别IC的Fc部分，可在包括DC在内的几种白细胞群中发现。然而，鉴于已知oxLDL结合其他细胞表面受体，包括TLR 4和CD 36，我们认为oxLDL-IC可能通过与几种细胞表面受体的伴随相互作用而增加炎症。我们将通过用oxLDL或oxLDL-IC处理来自野生型（C57 BL/6）小鼠和受体特异性敲除小鼠的骨髓来源的DC来测试该假设。将通过流式细胞术和细胞因子产生来测量活化。BMDC也将与T细胞共培养，以确定它们引发免疫应答的能力。在目标2中，我们 确定树突状细胞特异性Fc R对动脉粥样硬化的影响。由于DC具有强大的激活和分化幼稚T细胞的能力，从而控制下游免疫应答，DC Fc受体可能在介导动脉粥样硬化结果中很重要。为了鉴定DC Fc β R如何介导动脉粥样硬化，我们将野生型或Fc β R-/- DC过继转移到LDLr-/-小鼠中。此外，我们将对来自Fc ε Rflox/flox小鼠与CD 11 c Cre+小鼠杂交的后代进行骨髓移植，以获得LDLr-/-小鼠中的DC特异性Fc ε R敲除。总的来说，拟议的研究将确定oxLDL-IC在动脉粥样硬化中的作用。