An LXR protein interaction network controlling macrophage lipid transporter expression in response to inflammatory-lipid crosstalk

巨噬细胞泡沫细胞是动脉粥样硬化发展和病理的主要驱动力。暴露 巨噬细胞固醇脂质和炎症TLR信号改变基因调控网络控制脂质 体内平衡，这可以有利于泡沫细胞形成。在我们的理解中存在着一个根本性的差距。 TLR-脂质信号串扰影响这些网络并调节泡沫的分子机制 细胞形成。长期目标是了解泡沫细胞形成的分子机制， 用于动脉粥样硬化的治疗干预。阐明这些机制不仅将 推进我们对疾病病理学的理解，但也为功能相互作用提供了重要的见解 可以通过基因工程来增强脂质转运蛋白的表达，作为新的治疗方法的一部分， 对抗动脉粥样硬化本提案的目的是确定NCOA 5、SND 1和SART 1 其功能是控制脂质转运蛋白基因的表达、功能和泡沫细胞的形成。核心假设是 这些蛋白质是LXR转录复合物的关键组分，在基因调控区组装， 元件（GRES）的脂质转运蛋白Abca 1和Abcg 1，TLR-脂质串扰促进的变化， 这些复合物的组成和活性，通过磷酸化，有利于基因抑制，胆固醇 积累和泡沫细胞形成。根据初步数据，这一假设将通过以下方式进行检验： 本研究的目的有三：（1）阐明LXR相互作用蛋白在脂质转运蛋白调控中的作用 表达、功能和泡沫细胞形成;（2）阐明LXR相互作用蛋白磷酸化的作用 控制脂质转运蛋白表达、功能和泡沫细胞形成的蛋白质;以及（3）表征 在泡沫细胞形成过程中在脂质转运蛋白GRES上组装的LXR依赖性调节复合物，以及 评估体内NCOA 5在动脉粥样硬化中的作用。在第一个目标下，生物化学，分子和细胞 方法将用于解决NCOA 5，SND 1和SART 1在调节中的信号依赖性作用。 脂质转运蛋白的表达和泡沫细胞的形成。在第二个目标中，创新的目标群体 将使用质谱（MS）策略来鉴定磷酸化状态的信号依赖性变化， NCOA 5、SND 1和SART 1，然后将使用功能研究来确定这些影响 修改.对于第三个目标，创新的启动子富集定量MS（PE-QMS）方法将 用于表征在Abca 1和Abcg 1的GRES处组装的蛋白质复合物的组成， 体内泡沫细胞此外，我们将评估NCOA 5在促进泡沫细胞形成中的重要性， 体内动脉粥样硬化。这项拟议中的研究意义重大，因为它将提供机制来解释如何 泡沫细胞的形成在分子水平上受到调节，并提供了对蛋白质和相互作用的了解， 可以有针对性地重新设计基因调控网络，以防止泡沫细胞的形成， 动脉粥样硬化这有可能有益于患有这种疾病的患者的健康。

Macrophage foam cells are major drivers of the development and pathology of atherosclerosis. Exposure of macrophages to sterol lipid and inflammatory TLR signals modifies gene regulatory networks controlling lipid homeostasis, which can favor foam cell formation. There exists a fundamental gap in our understanding of the molecular mechanisms by which TLR-lipid signal crosstalk impinges upon these networks and regulates foam cell formation. The long-term goal is to understand the molecular mechanisms governing foam cell formation, for the purpose of therapeutic intervention in atherosclerosis. Elucidating these mechanisms will not only advance our understanding of disease pathology, but also provide crucial insights into functional interactions that could be engineered to enhance lipid transporter expression as part of new therapeutic approaches to counteract atherosclerosis. The objective of this proposal is to determine how NCOA5, SND1, and SART1 function to control lipid transporter gene expression, function and foam cell formation. The central hypothesis is that these proteins are critical components of LXR transcriptional complexes assembled at the gene regulatory elements (GREs) of lipid transporters Abca1 and Abcg1, and that TLR-lipid crosstalk promotes changes in the composition and activity of these complexes, through phosphorylation, that favor gene repression, cholesterol accumulation and foam cell formation. Based on preliminary data, this hypothesis will be tested by pursuing three specific aims: (1) Elucidate the function of LXR-interacting proteins in the control of lipid transporter expression, function and foam cell formation; (2) Elucidate the role of phosphorylation of LXR-interacting proteins in the control of lipid transporter expression, function and foam cell formation; and (3) Characterize LXR-dependent regulatory complexes assembled on lipid transporter GREs during foam cell formation, and assess the role of NCOA5 in atherosclerosis, in vivo. Under the first aim, biochemical, molecular, and cellular approaches will be used to address the signal-dependent role of NCOA5, SND1, and SART1 in regulating expression of lipid transporters and foam cell formation. In the second aim, an innovative targeted mass spectrometry (MS) strategy will be used to identify signal-dependent changes in the phosphorylation state of NCOA5, SND1, and SART1, which will then be pursued using functional studies to define the impact of those modifications. For the third aim, an innovative promoter enrichment quantitative MS (PE-QMS) approach will be employed to characterize the composition of protein complexes assembled at GREs of Abca1 and Abcg1 in foam cells in vivo. Moreover, we will assess the importance of NCOA5 in promoting foam cell formation and atherosclerosis in vivo. The proposed research is significant because it will provide mechanisms to explain how foam cell formation is regulated at the molecular level, and provide insights into proteins and interactions that can be targeted to re-engineer gene regulatory networks to prevent foam cell formation and counteract atherosclerosis. This has the potential to benefit the health of patients suffering from this disease.