Pim1 kinase coordinates PPAR gamma pathway and mitochondrial function to mediate pro-atherogenic responses in macrophages

动脉粥样硬化(AS)仍然是世界范围内主要的死亡原因，它经常与 血脂异常、氧化应激和线粒体功能障碍。巨噬细胞是一种先天免疫细胞 在AS的发展中起着至关重要的作用。巨噬细胞不受限制地摄取氧化型低密度脂蛋白 导致细胞内脂质堆积和泡沫细胞形成，这是AS早期的一个特征。 氧化低密度脂蛋白的摄取主要由CD36介导，CD36是巨噬细胞上高表达的清道夫受体 浮出水面。一个主要的问题是oxLDL通过转录导致CD36表达上调 因子PPARγ，产生正反馈机制，进一步增强CD36介导的oxLDL摄取。 定义这一过程的新型调节器是这个多PI提案的中心目标。最近出版的和 初步研究表明，Pim1是一种保守的丝氨酸/苏氨酸激酶，调节CD36的转录。在……里面 此外，巨噬细胞中pim1基因的遗传消融导致pPARγ途径的减少以及 下游靶点涉及脂肪酸代谢和线粒体氧化磷酸化。因此，我们 假设PIM1K协调PPARγ激活/CD36表达和线粒体功能 调节巨噬细胞的脂肪酸代谢和免疫激活。Pim1激酶的持续刺激 在巨噬细胞中有助于促动脉粥样硬化的表型和AS。具体目标1将决定 巨噬细胞中PIM1激酶协调PPARγ活化/CD36表达的分子机制 以及线粒体调节脂肪酸代谢的功能。我们将使用基因上的组合 改良巨噬细胞，生化，免疫学和体外细胞代谢研究，以确定 PIM1K通过PPARγ/CD36途径调节脂肪酸代谢的机制 确定Pim1激酶通过DRP-1和DRP-1调节线粒体形态的机制 定义对线粒体脂肪酸氧化、氧化磷酸化和ROS产生的影响。目标2 将检验体内灭活Pim1激酶可抑制AS发生的假说。使用 遗传性PIM1消融模型和PIM抑制剂AZD1208的微泵输注，我们的目的是测试 假设Pim1活性对于饮食诱导的小鼠是必不可少的；并检验这一假设 药物抑制PIM1抑制PPARγ/CD36途径并重新编程巨噬细胞 线粒体在致动脉粥样硬化条件下产生ROS；并检验Pim1的假设 在致动脉粥样硬化条件下调节骨髓-单核-巨噬细胞分化谱系。通过 阐明Pim1激酶调节脂肪酸代谢的分子机制 线粒体在致动脉粥样硬化条件下控制巨噬细胞激活的功能，我们预计将获得 掌握新的脂代谢调节剂的关键知识，并提供治疗AS的新策略。

Atherosclerosis (AS) remains the leading cause of death world-wide and it is often associated with dyslipidemia, oxidative stress and mitochondrial dysfunction. Macrophage is a type of innate immune cell that plays a critical role in the development of AS. Unrestricted uptake of oxidized LDL (oxLDL) by macrophages leads to accumulation of lipid intracellularly and foam cell formation, which is a hallmark of early stages of AS. OxLDL uptake is mainly mediated by CD36, a scavenger receptor highly expressed on the macrophage surface. One major problem is that oxLDL leads to up-regulation of CD36 expression through a transcription factor PPARγ, resulting in a positive feedback mechanism to further enhance CD36-mediated oxLDL uptake. Defining the novel regulator of this process is the central goal of this multi-PI proposal. Recent published and preliminary studies showed that Pim1, a conserved serine/threonine kinase regulates CD36 transcription. In addition, genetic ablation of pim1 gene in macrophages resulted in a reduction in PPARγ pathway as well as the downstream targets involved in fatty acid metabolism and mitochondrial oxidative phosphorylation. We thus hypothesized that Pim1 kinase coordinates PPARγ activation/CD36 expression and mitochondrial functions to regulate fatty acid metabolism and immune activation in macrophages. Continuous stimulation of Pim1 kinase in macrophages contributes to pro-atherogenic phenotypes and AS. Specific aim 1 will determine the molecular mechanism by which Pim1 kinase in macrophages coordinates PPARγ activation/CD36 expression and mitochondrial function to modulate fatty acid metabolism. We will use a combination of genetically modified macrophages, biochemical, immunological and ex vivo cell metabolic studies to determine the mechanisms by which Pim1 kinase regulates fatty acid metabolism through the PPARγ/CD36 pathway; and to determine the mechanisms by which Pim1 kinase regulates mitochondria morphology through Drp-1 and define the impact on mitochondria fatty acid oxidation, oxidative phosphorylation and ROS production. Aim 2 will test the hypothesis that inactivating Pim1 kinase in vivo suppresses the development of AS. Using the genetic pim1 ablation model and minipump infusion of the Pim inhibitor AZD1208, we aim to test the hypothesis that Pim1 activity is indispensible for diet-induced AS in mice; and to test the hypothesis that pharmacologic inhibition of Pim1 suppresses PPARγ/CD36 pathway and reprograms macrophage mitochondria toward ROS production under atherogenic conditions; and test the hypothesis that Pim1 regulates bone marrow-monocyte-macrophage differentiation lineage under atherogenic conditions. By elucidating the molecular mechanisms by which Pim1 kinase coordinates fatty acid metabolism and mitochondrial functions to control macrophage activation under atherogenic conditions, we expect to gain crucial knowledge on novel lipid metabolism regulators and provide new treatment strategies against AS.