Oxidation, immune modulation and atherogenesis in vivo

描述(由申请人提供)： 大量证据表明，免疫机制可以增强和 抑制动脉粥样硬化形成。我们之前已经证明，低密度脂蛋白的氧化会触发 广泛体液和细胞免疫反应和主动免疫 氧化低密度脂蛋白(OxLDL)可减少病变进展。高胆固醇血症 伴随而来的氧化应激增加也可能影响招募 通过调节动脉基因表达而产生的免疫活性细胞 干扰氧化敏感信号通路，包括NFkB， PPARGamma和细胞凋亡途径。第四单元将测试以下假设 在活体内：1)体液和细胞免疫反应都有助于 通过几种机制进行免疫的有利影响，包括消除 循环中氧化低密度脂蛋白的表达和分泌致动脉粥样硬化的Th1细胞的变化 干扰素γ刺激Th2细胞分泌抗动脉粥样硬化细胞因子；2) 维生素E和配体诱导的PPAR-γ激活减少血管内膜 通过干扰T细胞的氧化敏感调节来募集T细胞 动脉壁中的基因表达，以及3)促进损伤和抗原形成 在胎儿发育过程中影响体液和细胞免疫 在以后的生活中做出回应。体液免疫应答对鸡传染性非典型肺炎的影响 动脉粥样硬化及其潜在机制将被被动地确定 免疫正常和抗体缺陷(MU基因敲除)低密度脂蛋白受体缺陷 (LDLR-/-)小鼠具有氧化特异表位抗体。要确定 T细胞移位的发生及其对动脉粥样硬化的影响，我们将 比较氧化型低密度脂蛋白(可减少动脉粥样硬化)的免疫效果 与热休克蛋白65(它能增强它)的免疫效果相比。这个 T细胞免疫的贡献将通过转移T细胞来建立 免疫小鼠的细胞或T细胞亚群进入幼稚的接受者。这个 抗氧化剂的作用，自然降低低密度脂蛋白氧化(脂氧合酶 缺乏)，以及PPARγ激活对动脉基因表达和T细胞的影响 在不同阶段的皮损中重新招募将通过 微阵列、实时聚合酶链式反应、免疫细胞化学和基于聚合酶链式反应的T细胞追踪 LDLR-/-小鼠和12/15脂氧合酶缺陷LDLR-/-小鼠中的细胞。至 确定胎儿期抗原形成增加的后果 出生后免疫反应的发展，胎儿病变的形成 母体暴露于高胆固醇血症可增强小鼠的免疫力。这些 实验将提供更好的理解机制，通过它 氧化低密度脂蛋白的免疫反应调节动脉粥样硬化的形成，并可能导致新的 采取预防性的方法。

DESCRIPTION (provided by the applicant): Substantial evidence indicates that immune mechanisms may both enhance and inhibit atherogenesis. We previously showed that oxidation of LDL triggers extensive humoral and cellular immune responses and that active immunization with oxidized LDL (OxLDL) reduces lesion progression. Hypercholesterolemia and concomitant increased oxidative stress may also influence the recruitment of immune-competent cells by modulating arterial gene expression through interference with oxidation-sensitive signaling pathways, including NFkB, PPARgamma, and apoptotic pathways. Unit 4 will test the following hypotheses in vivo: 1) that both humoral and cellular immune responses contribute to the beneficial effect of immunization by several mechanisms, including the removal of OxLDL from the circulation and shifts from Thl cells secreting pro-atherogenic IFNgamma to Th2 cells secreting antiatherogenic cytokines; 2) that vitamin E and ligand-induced PPARgamma activation reduce the intimal recruitment of T cells by interfering with oxidation-sensitive regulation of gene expression in the arterial wall, and 3) that enhanced lesion and antigen-formation during fetal development influences humoral and cellular immune responses later in life. The effects of humoral immune responses on atherosclerosis and the underlying mechanisms will be determined by passively immunizing normal and antibody-deficient (mu knockout) LDL receptor-deficient (LDLR-/-) mice with antibodies to oxidation-specific epitopes. To determine the occurrence of T cell shifts and their impact on atherogenesis, we will compare the effects of immunization with OxLDL (which reduces atherosclerosis) to those of immunization with heat shock protein 65 (which enhances it). The contribution of T cell-mediated immunity will be established by transferring T cells or T cell subsets from immunized mice into naive recipients. The effects of antioxidants, naturally decreased LDL oxidation (lipoxygenase deficiency), and PPARgamma activation on arterial gene expression and T cell recruitment into lesions of different stages will be established by microarrays, real-time PCR, immunocytochemistry, and PCR-based tracking of T cells in LDLR-/- mice and 12/15 lipoxygenase deficient LDLR-/- mice. To determine the consequences of increased antigen formation during fetal development on postnatal immune responses, fetal lesion formation will be enhanced in mice by maternal exposure to hypercholesterolemia. These experiments will provide a better understanding of the mechanisms by which immune responses to OxLDL modulate atherogenesis and potentially lead to new preventive approaches.