HDL regulates TGFß-receptor lipid raft partitioning, restoring contractile features of cholesterol-loaded vascular smooth muscle cells.
HDL regulates TGFß-receptor lipid raft partitioning, restoring contractile features of cholesterol-loaded vascular smooth muscle cells.
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HDL 调节 TGFα 受体脂筏分配，恢复负载胆固醇的血管平滑肌细胞的收缩特征。
DOI：
10.1101/2023.10.19.562786
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发表时间：
2023
期刊：
影响因子：
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通讯作者：
Fisher,EdwardA
中科院分区：
文献类型：
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作者：
Nagesh,PrashanthThevkar;Nishi,Hitoo;Rawal,Shruti;Zahr,Tarik;Miano,JosephM;Sorci-Thomas,Mary;Xu,Hao;Akbar,Naveed;Choudhury,RobinP;Misra,Ashish;Fisher,EdwardA
小鼠主动脉血管平滑肌细胞（mVSMCs）的胆固醇负荷下调mir -143/145，这是TGFβ信号下游收缩状态的主要调节因子。在体外，这导致从收缩的mVSMC过渡到巨噬细胞样状态。根据对小鼠和人类动脉粥样硬化斑块的研究，这一过程可能发生在体内。目的观察体外和体内胆固醇负荷是否会降低VSMC tgf - β信号通路，以及胆固醇外排是否会恢复信号通路和收缩状态。方法对人冠状动脉(h)VSMCs进行胆固醇负荷，然后用HDL治疗（促进胆固醇外排）。在体内研究中，诱导了谱系追踪的VSMC小鼠tgf βr2的部分条件缺失。vsmctgf βr2野生型或部分缺乏（Tgfβr2+/-）小鼠被制成高胆固醇血症以建立动脉粥样硬化。然后用apoA1（形成HDL）处理小鼠。结果高胆固醇负荷的hVSMCs下调tgf - β信号通路和收缩基因表达；诱导巨噬细胞标志物。TGFβ信号正调控mir -143/145表达，增加acta2表达，抑制KLF4。胆固醇负荷将TGFβ受体定位到脂筏中，导致TGFβ信号下调。值得注意的是，在胆固醇负荷的hVSMCs中，HDL颗粒从脂筏中取代受体，增加TGFβ信号，导致mir -145表达增强，减少klf4依赖性巨噬细胞特征。ApoA1输注TGFβ r2+/-小鼠恢复了斑块VSMCs中dacta2的表达，并降低了巨噬细胞标志物的表达，并有证据表明TGFβ信号传导增加。结论胆固醇通过将tgf - β受体分配到脂质筏中，抑制tgf - β信号通路和hVSMC的收缩状态。这些变化可以通过促进胆固醇外排来逆转，这与体内的证据一致。在人和小鼠的动脉粥样硬化斑块中，许多被鉴定为巨噬细胞样的细胞被认为起源于VSMC。我们通过膜脂筏中TGFβ受体的定位发现了胆固醇介导的vitroin human (h)VSMCs中TGFβ信号的下调，这被hdl介导的胆固醇外排逆转。通过促进TGFβ增强mir -145表达，恢复VSMC收缩标志物（Acta2）并抑制巨噬细胞标志物（CD68）的表达。在体内，给动脉粥样硬化小鼠apoA1（形成HDL）也促进了vsmcacta2的表达，降低了CD68的表达。由于巨噬细胞样VSMC被认为具有不利的特性，我们的研究不仅从机制上揭示了胆固醇如何导致其转变，而且还表明外溢能力强的HDL颗粒可能通过在动脉粥样硬化斑块中恢复更有利的VSMC表型状态而具有治疗作用。
BackgroundCholesterol-loading of mouse aortic vascular smooth muscle cells (mVSMCs) downregulatesmiR-143/145, a master regulator of the contractile state downstream of TGFβ signaling.In vitro,this results in transitioning from a contractile mVSMC to a macrophage-like state. This process likely occursin vivobased on studies in mouse and human atherosclerotic plaques.ObjectivesTo test whether cholesterol-loading reduces VSMC TGFβ signaling and if cholesterol efflux will restore signaling and the contractile statein vitroandin vivo.MethodsHuman coronary artery (h)VSMCs were cholesterol-loaded, then treated with HDL (to promote cholesterol efflux). Forin vivostudies, partial conditional deletion ofTgfβr2in lineage-traced VSMC mice was induced. Mice wild-type for VSMCTgfβr2or partially deficient (Tgfβr2+/-) were made hypercholesterolemic to establish atherosclerosis. Mice were then treated with apoA1 (which forms HDL).ResultsCholesterol-loading of hVSMCs downregulated TGFβ signaling and contractile gene expression; macrophage markers were induced. TGFβ signaling positively regulatedmiR-143/145expression, increasingActa2expression and suppressing KLF4. Cholesterol-loading localized TGFβ receptors into lipid rafts, with consequent TGFβ signaling downregulation. Notably, in cholesterol-loaded hVSMCs HDL particles displaced receptors from lipid rafts and increased TGFβ signaling, resulting in enhancedmiR-145expression and decreased KLF4-dependent macrophage features. ApoA1 infusion intoTgfβr2+/-mice restoredActa2expression and decreased macrophage-marker expression in plaque VSMCs, with evidence of increased TGFβ signaling.ConclusionsCholesterol suppresses TGFβ signaling and the contractile state in hVSMC through partitioning of TGFβ receptors into lipid rafts. These changes can be reversed by promotion of cholesterol efflux, consistent with evidencein vivo.Condensed abstractMany cells identified as macrophage-like in human and mouse atherosclerotic plaques are thought to be of VSMC origin. We identified cholesterol-mediated downregulation of TGFβ signalingin vitroin human (h)VSMCs by localization of TGFβ receptors in membrane lipid rafts, which was reversed by HDL-mediated cholesterol efflux. This restored VSMC contractile marker (Acta2) and suppressed macrophage marker (CD68) expression by promoting TGFβ enhancement ofmiR-145expression.In vivo, administration of apoA1 (which forms HDL) to atherosclerotic mice also promoted VSMCActa2expression and reduced CD68 expression. Because macrophage-like VSMC are thought to have adverse properties, our studies not only show mechanistically how cholesterol causes their transition, but also suggest that efflux-competent HDL particles may have a therapeutic role by restoring a more favorable phenotypic state of VSMC in atherosclerotic plaques.