Investigating mechanisms of oxidized phospholipid-mediated dysregulation of regulatory T cells in atherosclerosis

总结 适应性免疫在心血管疾病（CVD）中的重要作用已经确立。然而，许多仍然 关于如何操纵适应性免疫以使CVD结果受益的信息尚不清楚。动脉粥样硬化 最常见的CVD形式的特征是脂质和免疫细胞在动脉壁中的积累， 导致斑块形成。最近在人类动脉粥样硬化中的单细胞RNAseq数据证实，T细胞使 在病变中的大部分细胞群。T细胞对动脉粥样硬化过程很重要， 效应T细胞（Th 1和Th 17）似乎促进斑块生长和不稳定性，而调节性T细胞 （TdR）对于抑制动脉粥样硬化形成和诱导已建立的斑块消退是关键的。在人类中， 与斑块稳定性和防止心脏事件有关。这些数据是一致 小鼠模型显示斑块中的Tcl 3数量随着动脉粥样硬化的进展而减少， Th 1样炎性表型。为什么动脉粥样硬化中的甲状腺去分化或功能障碍 完全理解，但最近的研究表明，氧化低密度脂蛋白（oxLDL）可能发挥作用， 在这一过程中的作用。我们实验室的初步研究检测了氧化磷脂 与动脉粥样硬化和oxLDL相关的oxPAPC可影响Treg的分化、稳定性和功能。 我们的初步数据表明，oxPAPC降低Treg活性，增加Th 1相关免疫球蛋白的表达。 转录因子T-bet和IFN-γ的产生，从而促进Th 1样Treg表型。该效应 Treg特异性细胞在Th 1或Th 17条件下不受oxPAPC的影响。这些oxPAPC肽 在体外的抑制性也较低。oxPAPC对T细胞增殖的影响部分依赖于CD 36和IFN-γ。 有趣的是，IFN-γ已经显示出在肿瘤微环境中使TcB不稳定，并且该提议中的数据 显示在Treg偏斜培养物中IFN-γ中和抑制FoxP 3+细胞中T-bet的表达。因此，我们认为， 我们假设与动脉粥样硬化相关的氧化磷脂诱导了一种效应物， 在TcB中的表型部分依赖于IFN-γ。为了验证这一假设，我们提出了两个具体的 目标。第一部分将研究CD 36/TLR和IFN-γ信号转导对Tcl 3在肿瘤细胞中的失调的作用。 oxPL的存在，并确定这些TCLs是否可以在体内保护免受动脉粥样硬化。第二，威尔 检查CD 36或对IFN-γ的应答是否是Treg区室不稳定的原因 在体内动脉粥样硬化过程中。这项工作将揭示新的信息氧化磷脂的作用， Treg功能障碍在动脉粥样硬化中的作用，将为未来的临床干预提供有价值的见解。

SUMMARY The important role of adaptive immunity in cardiovascular disease (CVD) is established. However, much is still unknown regarding how adaptive immunity can be manipulated to benefit CVD outcomes. Atherosclerosis, the most common form of CVD, is characterized by accumulation of lipid and immune cells in the artery wall that leads to plaque formation. Recent single cell RNAseq data in human atherosclerotic confirm that T cells make up a large fraction of the cell population in lesions. T cells are important to the atherosclerotic process as effector T cells (Th1 and Th17) seem to promote plaque growth and instability whereas regulatory T cells (Tregs) are critical for inhibition of atherogenesis and induce regression of established plaques. In humans, Tregs are associated with plaque stability and protection against cardiac events. These data are consistent with mouse models that show Tregs numbers in plaques decrease as atherosclerosis progresses and remaining Tregs Th1-like inflammatory phenotype. Why Tregs dedifferentiate or become dysfunctional in atherosclerosis is not completely understood, but recent studies suggest that oxidized low density lipoprotein (oxLDL) may play a functional role in this process. Preliminary studies from our laboratory examined whether oxidized phospholipid (oxPAPC), associated with atherosclerosis and oxLDL, could affect Treg differentiation, stability, and function. Our preliminary data show that, oxPAPC reduced Treg viability and increased expression of the Th1-associated transcription factor T-bet and production of IFN- thus promoting the Th1-like Treg phenotype. This effect was Treg-specific as cells skewed in Th1 or Th17 conditions were not affected by oxPAPC. These oxPAPC Tregs were also less suppressive in vitro. The effect of oxPAPC on Tregs was partially dependent on CD36 and IFN-. Interestingly, IFN- has been shown to destabilize Tregs in the tumor microenvironment and data in this proposal show that neutralization of IFN- in Treg skewing cultures inhibits expression of T-bet in FoxP3+ cells. Therefore, we hypothesize that oxidized phospholipids associated with atherosclerosis induce an effector- phenotype in Tregs that is partially dependent on IFN-. To test this hypothesis we propose two specific aims. The first will examine the role of CD36/TLR and IFN- signaling on the dysregulation of Tregs in the presence of oxPLs and determine if these Tregs can protect from atherosclerosis in vivo. The second, will examine whether CD36 or responses to IFN- are responsible for destabilization of the Treg compartment during atherosclerosis in vivo. This work will uncover novel information on the role of oxidized phospholipid on Treg dysfunction in atherosclerosis and will provide valuable insight for future clinical interventions.