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

• 批准号: 10640873
• 负责人: Steve Lim
• 金额: $ 36.97万
• 依托单位: UNIVERSITY OF ALABAMA AT BIRMINGHAM
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-08-01 至 2025-06-30
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10640873
• 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; Macrophage; Mediating; Modeling; Molecular; Mus; Myocardial Infarction; Myocardial Ischemia; Nuclear; Nuclear Protein; Nuclear Translocation; Patients; Peroxisome Proliferator-Activated Receptors; Phosphotransferases; Population; Preventive; Proliferating; Protein Tyrosine Kinase; Regulation; Role; SMRT protein; Signal Transduction; Therapeutic; antiporter; cell motility; filamin; insight; mortality; mouse model; oxidized low density lipoprotein; patient subsets; pharmacologic; prevent; scavenger receptor; sensor; targeted treatment; uptake; western diet

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.

项目摘要 动脉粥样硬化是胆固醇在血管细胞内过度积聚的结果， 在动脉粥样硬化病变中，巨噬细胞构成了这些富含脂质的泡沫细胞的大部分。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，以治疗更大比例的动脉粥样硬化患者 降低心血管疾病死亡率。治疗动脉粥样硬化的一个潜在策略是减少泡沫 通过减少巨噬细胞的胆固醇摄取(内流)和/或促进胆固醇的释放(外流)。 然而，目前还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 由过多的胆固醇流入而没有有效的外流发展而来。粘着斑激酶(FAK)是一种整合素- 相关的酪氨酸激酶，促进血管细胞迁移、增殖和炎症。我们 发现了FAK在调节巨噬细胞内脂质稳态方面的新功能。我们的 初步数据显示，氧化低密度脂蛋白(OxLDL)刺激后FAK激活 是通过内吞CD36形成泡沫细胞所必需的。此外，oxLDL增加了FAK的相互作用 重要的是，药理上的FAK抑制阻断了FAK-CD36-微丝A的相互作用 和随后泡沫细胞的形成，表明三元复合体可能有助于oxLDL的摄取。 更有趣的是，抑制FAK增加了细胞脂质感受器过氧化物体增殖物的表达 活化的受体g(PPARg)和肝X受体a(LXRa)导致 胆固醇拮抗剂Abcg1和ABCA1。FAK抑制也增加了PPARg和LXRa核 易位，这与核受体辅阻遏子2(NCOR2)的表达减少有关。 在一种新的基于ApoE-/-背景的巨噬细胞特异性FAK激酶死亡(KD)小鼠模型(CSF1R-ICRE)中，我们 观察到，喂食西方饮食(WD)的FAK-KD小鼠显示出较少的泡沫细胞形成和减少 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 破坏FAK-细丝蛋白A-CD36复合体的形成，同时通过增加 PPARG和LXRa通过NCOR2降解激活。为了破译一种分子机制，在这种机制中，两个 FAK的作用是阻止巨噬细胞摄取胆固醇并促进其外流。AIM 1将确定FAK 和丝素A对巨噬细胞摄取oxLDL-CD36的调节。AIM 2将调查FAK对 泡沫细胞中胆固醇通过PPARg和LXRa的激活而外流。目标3将评估FAK抑制的效果 论动脉粥样硬化的防治模式。拟议中的研究将对这一角色提供新的见解 FAK在巨噬细胞泡沫细胞胆固醇稳态中的作用 通过减少胆固醇流入和增加胆固醇流出来减少泡沫细胞，从而导致动脉粥样硬化。