Effects of Anti-miR-33 on Atherosclerosis Regression and RCT in Nonhuman Primates

项目摘要 冠心病(CHD)是美国人最大的主要杀手，其风险与 高密度脂蛋白胆固醇(HDLC)。高密度脂蛋白胆固醇的保护作用被认为是由于 高密度脂蛋白在胆固醇反向转运(RCT)中的作用，即巨噬细胞泡沫细胞中的胆固醇 在动脉粥样硬化斑块中被排出到高密度脂蛋白，运输到肝脏，并在粪便中排泄。尽管 积极努力寻找新的治疗策略来提高高密度脂蛋白，这已被证明是一项具有挑战性的努力。 一个新的、有希望提高高密度脂蛋白胆固醇和RCT的靶点是microRNA-33(miR-33)。在人类中，有两个 该microRNA的异构体miR-33a和miR-33b编码于固醇反应元件的内含子中 结合因子(SREBF)2和SREBF1基因，并与其宿主基因共同调节细胞内脂平衡。 值得注意的是，miR-33a/b诱导了与胆固醇相关的基因的mRNA降解和/或翻译抑制 外排和脂肪酸氧化。MiR-33a/b的主要靶点是三磷酸腺苷结合盒转运体A1 (ABCA1)，一种对泡沫细胞的胆固醇外流和高密度脂蛋白的形成至关重要的蛋白质。在老鼠身上，这是 仅编码miR-33a，针对miR-33的反义寡核苷酸(抗miR-33)可增加肝脏和 巨噬细胞ABCA1、高密度脂蛋白胆固醇、RCT与动脉粥样硬化消退。然而，翻译的价值在于 在老鼠身上的研究受到miR-33b缺乏的限制，miR-33b在人类和非人类灵长类动物中都有表达。 为了测试同时抑制miR-33a和miR-33b的效果，我们最近用抗miR-33a和miR-33b的抗体治疗非洲绿猴。 33发现肝脏ABCA1和HDLc升高，极低密度脂蛋白(VLDL)甘油三酯 是减少的。虽然迄今为止的临床前研究结果强调了抗miR-33的心脏保护潜力，但 在同时表达miR-33和miR-33的类人物种中，抗miR-33诱导动脉粥样硬化消退的能力 MiR-33a和miR-33b仍然未知。在这个应用中，我们建议确定抗miR-33的效果 非人灵长类动物动脉粥样硬化消退与随机对照试验。这些研究将大大有助于评估 抗miR-33作为一种潜在的冠心病临床治疗方法。

Project Summary The risk of coronary heart disease (CHD), the largest major killer of Americans, is inversely associated with high-density lipoprotein cholesterol (HDL-C). The protective effects of HDL-C are believed to be due to the role of HDL in reverse cholesterol transport (RCT), a process whereby cholesterol from macrophage foam cells in atherosclerotic plaques is effluxed to HDL, transported to the liver, and excreted in the feces. Despite intense efforts to identify new therapeutic strategies to raise HDL, this has proven to be a challenging endeavor. A new and promising target for increasing HDL-C and RCT is microRNA-33 (miR-33). In humans, two isoforms of this microRNA, miR-33a and miR-33b, are encoded in introns of the sterol response element binding factor (SREBF) 2 and SREBF1 genes, and co-regulate cellular lipid homeostasis with their host genes. Notably, miR-33a/b induce mRNA degradation and/or translational repression of genes involved in cholesterol efflux and fatty acid oxidation. A major target of miR-33a/b is the ATP binding cassette transporter A1 (ABCA1), a protein essential for cholesterol efflux from foam cells and the formation of HDL. In mice, which encode only miR-33a, an antisense oligonucleotide targeting miR-33 (anti-miR-33) increased hepatic and macrophage ABCA1, HDL-C, RCT, and atherosclerosis regression. However the translational value of the studies in mice was limited by the lack of miR-33b, which is expressed in humans and non-humans primates. To test the effects of inhibiting both miR-33a and b, we recently treated African green monkeys with anti-miR- 33 and found that hepatic ABCA1 and HDL-C was elevated and very low-density lipoprotein (VLDL) triglyceride was decreased. While the preclinical findings to date highlight the cardioprotective potential of anti-miR-33, the ability of anti-miR-33 to induce the regression of atherosclerosis in a "human-like" species expressing both miR-33a and miR-33b is still unknown. In this application, we propose to determine the effects of anti-miR-33 on atherosclerosis regression and RCT in non-human primates. These studies will greatly aid in assessing anti-miR-33 as a potential clinical treatment for CHD.