FAK regulation of cholesterol influx and efflux in foam cells

FAK 对泡沫细胞中胆固醇流入和流出的调节

基本信息

批准号：
10427440
负责人：
Steve Lim
金额：
$ 0.67万
依托单位：
UNIVERSITY OF SOUTH ALABAMA
依托单位国家：
美国
项目类别：
财政年份：
2021
资助国家：
美国
起止时间：
2021-08-01 至 2022-08-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10427440
关键词：
ATP binding cassette transporter 1 Actins Apolipoprotein E Arterial Fatty Streak Arteries Atherosclerosis Blood Vessels CD36 gene CSF1R gene Cardiovascular Diseases Cause of Death Cells Cholesterol Cholesterol Homeostasis Complex Data Endocytosis Equilibrium Excision Foam Cells Focal Adhesion Kinase 1 Gene Expression Genetic Genetic Transcription Homeostasis Inflammation Integrins Ischemic Stroke LXRalpha protein Lipids Mediating Modeling Molecular Mus Myocardial Infarction NCOR2 gene Nuclear Nuclear Protein Nuclear Receptors Nuclear Translocation PPAR alpha PPAR gamma Patients Pharmacology Phosphotransferases Population Preventive Protein Tyrosine Kinase Regulation Role Signal Transduction Therapeutic antiporter cell motility filamin genetic corepressor insight macrophage mortality mouse model oxidized low density lipoprotein patient subsets prevent scavenger receptor sensor targeted treatment uptake western diet

项目摘要

Project Summary Atherosclerosis arises as a result of excess accumulation of cholesterol within vascular cells, with macrophages comprising a majority of these lipid-laden foam cells within atherosclerotic lesions. Lipid-lowering therapies, such as statins, have proven beneficial, but still only benefit a subset of patients. As such, there is currently a need to develop new treatment options that can treat a larger portion of atherosclerosis patients to reduce cardiovascular disease mortality. One potential strategy for treating atherosclerosis is to reduce foam cells by decreasing cholesterol uptake (influx) and/or to promote cholesterol release (efflux) in macrophages. However, no current therapy targets these mechanisms. Foam cells within atherosclerotic lesions are developed from too much cholesterol influx without efficient efflux. Focal adhesion kinase (FAK) is an integrin- associated tyrosine kinase which contributes to vascular cell migration, proliferation, and inflammation. We have discovered new functions for FAK in the regulation of lipid homeostasis within macrophages. Our preliminary data revealed that FAK activation following oxidized low-density lipoprotein (oxLDL) stimulation was required for foam cell formation via endocytosis of CD36. Additionally, oxLDL increased FAK interaction with CD36 and Filamin A. Importantly, pharmacological FAK inhibition blocked FAK-CD36-Filamin A interaction and subsequent foam cell formation, suggesting that the ternary complex may contribute to oxLDL uptake. More interestingly, FAK inhibition increased expression of cellular lipid sensors peroxisome proliferator activated receptor g (PPARg) and liver X receptor a (LXRa) resulting in increased transcription of the cholesterol antiporters ABCG1 and ABCA1. FAK inhibition also increased PPARg and LXRa nuclear translocation, and this was associated with decreased expression of nuclear receptor corepressor 2 (NCOR2). In a new macrophage-specific FAK kinase-dead (KD) mouse model (CSF1R-iCre) on ApoE-/- background, we observed that FAK-KD mice fed a western diet (WD) showed less foam cell formation and reduced atherosclerotic lesions. Taken together, our central hypothesis is that FAK inhibition reduces oxLDL uptake via disruption of FAK-Filamin A-CD36 complex formation while also increasing cholesterol efflux through increased PPARg and LXRa activation via NCOR2 degradation. To decipher a molecular mechanism in which a two-fold role of FAK prevents cholesterol uptake as well as enhances efflux in macrophages. Aim 1 will determine FAK and Filamin A regulation of oxLDL-CD36 uptake in macrophages. Aim 2 will investigate FAK regulation of cholesterol efflux via PPARg and LXRa activation in foam cells. Aim 3 will evaluate the effect of FAK inhibition on preventive and therapeutic models of atherosclerosis. The proposed study will shed new insights on the role of FAK in cholesterol homeostasis in macrophage foam cells and could produce a new treatment option in atherosclerosis by reducing the foam cells via reduced cholesterol influx and elevated cholesterol efflux.

项目概要动脉粥样硬化是由于血管细胞内胆固醇过度积累而引起的，动脉粥样硬化病变内的这些充满脂质的泡沫细胞大部分由巨噬细胞组成。降脂他汀类药物等疗法已被证明是有益的，但仍然只使一小部分患者受益。因此，有目前需要开发新的治疗方案来治疗大部分动脉粥样硬化患者降低心血管疾病死亡率。治疗动脉粥样硬化的一种潜在策略是减少泡沫通过减少巨噬细胞中胆固醇的摄取（流入）和/或促进胆固醇释放（流出）。然而，目前没有针对这些机制的治疗方法。动脉粥样硬化病变内的泡沫细胞是由过多的胆固醇流入而没有有效的流出而发展而来。粘着斑激酶 (FAK) 是一种整合素相关酪氨酸激酶有助于血管细胞迁移、增殖和炎症。我们发现了 FAK 在巨噬细胞内脂质稳态调节中的新功能。我们的初步数据显示，氧化低密度脂蛋白 (oxLDL) 刺激后 FAK 激活通过 CD36 的内吞作用形成泡沫细胞。此外，oxLDL 增加了 FAK 相互作用重要的是，药理学 FAK 抑制可阻断 FAK-CD36-Filamin A 相互作用以及随后的泡沫细胞形成，表明三元复合物可能有助于 oxLDL 的摄取。更有趣的是，FAK 抑制增加了细胞脂质传感器过氧化物酶体增殖物的表达激活受体 g (PPARg) 和肝 X 受体 a (LXRa) 导致转录增加胆固醇逆向转运蛋白 ABCG1 和 ABCA1。 FAK 抑制还增加了 PPARg 和 LXRa 核易位，这与核受体辅阻遏物 2 (NCOR2) 表达减少有关。在 ApoE-/- 背景下的新巨噬细胞特异性 FAK 激酶死亡 (KD) 小鼠模型 (CSF1R-iCre) 中，我们观察到饲喂西方饮食 (WD) 的 FAK-KD 小鼠表现出较少的泡沫细胞形成并减少动脉粥样硬化病变。综上所述，我们的中心假设是 FAK 抑制通过以下途径减少 oxLDL 的摄取：破坏 FAK-Filamin A-CD36 复合物形成，同时还通过增加胆固醇流出来增加通过 NCOR2 降解激活 PPARg 和 LXRa。破译双重分子机制 FAK 的作用是防止胆固醇摄取并增强巨噬细胞的流出。目标 1 将确定 FAK 和 Filamin A 对巨噬细胞中 oxLDL-CD36 摄取的调节。目标 2 将调查 FAK 监管通过泡沫细胞中 PPARg 和 LXRa 的激活，胆固醇流出。目标 3 将评估 FAK 抑制的效果动脉粥样硬化的预防和治疗模型。拟议的研究将为该角色提供新的见解 FAK 在巨噬细胞泡沫细胞胆固醇稳态中的作用，可能会产生一种新的治疗选择通过减少胆固醇流入和增加胆固醇流出来减少泡沫细胞，从而预防动脉粥样硬化。