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: 10278516
• 负责人: Steve Lim
• 金额: $ 38.5万
• 依托单位: UNIVERSITY OF SOUTH ALABAMA
• 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/10278516
• 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

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 动脉粥样硬化是由于胆固醇在血管细胞内过度积累而引起的， 巨噬细胞包含动脉粥样硬化病变内的大多数这些载脂泡沫细胞。降脂 诸如他汀类药物的治疗已被证明是有益的，但仍然仅使一部分患者受益。因此， 目前需要开发新的治疗选择，其可以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个潜在策略是减少泡沫 通过减少巨噬细胞中的胆固醇摄取（流入）和/或促进胆固醇释放（流出）来抑制细胞中的胆固醇。 然而，目前没有针对这些机制的治疗。动脉粥样硬化病变内的泡沫细胞 由于胆固醇过多流入而没有有效流出而形成。粘着斑激酶（FAK）是一种整合素- 与酪氨酸激酶相关的蛋白激酶，其有助于血管细胞迁移、增殖和炎症。我们 已经发现FAK在调节巨噬细胞内脂质稳态中的新功能。我们 初步数据显示，氧化低密度脂蛋白（oxLDL）刺激后FAK活化 是通过CD 36的内吞作用形成泡沫细胞所必需的。此外，oxLDL增加FAK相互作用， 与CD 36和细丝蛋白A结合重要的是，药理学FAK抑制阻断FAK-CD 36-细丝蛋白A相互作用 和随后的泡沫细胞形成，这表明三元复合物可能有助于oxLDL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），从而导致 胆固醇反向转运蛋白ABCG 1和ABCA 1。FAK抑制还增加了PPARg和LXR α核表达。 易位，这与核受体辅阻遏物2（NCOR 2）的表达减少有关。 在ApoE-/-背景的新的巨噬细胞特异性FAK激酶死亡（KD）小鼠模型（CSF 1 R-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的 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摄取： 破坏FAK-细丝蛋白A-CD 36复合物的形成，同时也通过增加胆固醇流出增加胆固醇流出。 PPARg和LXRa通过NCOR 2降解活化。为了破译一种分子机制， FAK的作用是阻止胆固醇摄取以及增强巨噬细胞的流出。目标1将决定FAK 和细丝蛋白A调节巨噬细胞中oxLDL-CD 36摄取。目标2将研究FAK调节 泡沫细胞中通过PPARg和LXR α活化的胆固醇流出。目的3：评价FAK抑制剂的作用 动脉粥样硬化的预防和治疗模型。这项拟议中的研究将对这一作用提出新的见解。 FAK在巨噬细胞泡沫细胞中胆固醇稳态中的作用，并可能在 动脉粥样硬化通过减少泡沫细胞经由减少的胆固醇流入和升高的胆固醇流出。