Mechanisms and Modulation of Accelerated Atherosclerosis in Clonal Hematopoiesis

项目概要/摘要 随着年龄的增长，人类可以在血液中积累来自骨髓体细胞突变的白细胞克隆 增强扩增干细胞：不确定潜能的克隆造血（CHIP）。突变 DNMT3A和TET2占这些克隆的多个。CHIP导致心血管（CV）高度升高 风险，独立于传统的风险因素。我们已经发现动脉粥样硬化的加速形成， Tet2或Dnmt3a功能髓样缺失且IL-6信号传导遗传性降低的小鼠中的IL-1和IL-6 消除了使用DNMT3A或TET2 CHIP的人中升高的CV风险。对我们的CANTOS试验的分析表明， 在使用DNMT3A或TET2 CHIP的人中，IL-1 β抑制的功效更大。这些结果指出了一条通往 基因型导向的治疗分配，这种方法已经改变了肿瘤学，但在 动脉粥样硬化经典与反式IL-6信号在动脉粥样硬化血栓形成中的作用需要进一步研究， 相互矛盾的证据具体目标1将检验以下假设，即模拟CHIP的动脉粥样硬化小鼠由于 用通过中和IL-6而中断总体IL-6信号传导的抗体治疗的Dnmt3a中的髓样缺陷 受体α（IL-6r，CD126）减少了动脉粥样硬化和炎症病变，血液和其他 部分通过单细胞RNA测序（scRNA-seq）测量器官。我们进一步假设IL-6r 抑制将限制突变克隆的扩增。具体目标2将探讨经典与反式IL-6的作用 使用Il6rflox/flox/Lyz2-Cre小鼠骨髓在CHIP中加速动脉粥样硬化形成的髓样细胞中的信号传导 嵌合LDLR-/-小鼠（阻断白细胞经典信号传导），并给予gp130-IgG1-Fc嵌合LDLR-/-小鼠（阻断白细胞经典信号传导）。 蛋白质（以阻断反式信号传导）使用类似的程序和终点。结果将阐明 关于经典和反式IL-6信号传导对 动脉粥样硬化具体目标3。我们的初步实验表明，雌性MyeloidTet2-/-Ldlr-/-小鼠 与Tet2 +/+ Ldlr-/-雄性小鼠相比，动脉粥样硬化形成的加速更大，并且与它们的雄性对应物不同， 通过IL-1 β中和作用减少动脉粥样硬化形成。我们将定位这种性别差异在哪里运作， 炎症体-IL-1 β-IL-6途径，并检验雌性Dnmt3a-/-Ldlr-/-小鼠具有更大的炎症反应的假设 IL-6r抑制的反应。我们将通过性腺消融实验和 scRNA-seq数据分析，初步数据显示IL-1 β在驻留巨噬细胞中表达 Tet2-/-女性而非男性的动脉粥样化。这项工作将加深对 加速了CHIP中的动脉粥样硬化。我们新的试点临床数据表明，抗IL-6抗体可以使 人类的炎症因此，这里提出的工作将为验证提供不可缺少的一步 并提供了一个直接可转化的靶向治疗策略的基本基础， CHIP基因型。

Project Summary/Abstract With age, humans can accumulate leukocyte clones in blood that arise from somatic mutations in bone marrow stem cells that enhance expansion: clonal hematopoiesis of indeterminate potential (CHIP). Mutations in DNMT3A and TET2 account for the plurality of these clones. CHIP confers highly elevated cardiovascular (CV) risk, independent of traditional risk factors. We have found accelerated atherogenesis and the involvement of IL-1 and IL-6 in mice with myeloid loss of Tet2 or Dnmt3a function and that genetically reduced IL-6 signaling abrogates the elevated CV risk in humans with DNMT3A or TET2 CHIP. Analyses of our CANTOS trial showed greater efficacy of IL-1β inhibition in humans with DNMT3A or TET2 CHIP. These results point the way to a genotype-directed allocation of therapy, an approach that has transformed oncology but remains aspirational in atherosclerosis. The roles of classical vs. trans IL-6 signaling in atherothrombosis requires further study due to conflicting evidence. Specific aim 1 will test the hypothesis that atherosclerotic mice that mimic CHIP due to myeloid deficiency in Dnmt3a treated with an antibody that interrupts global IL-6 signaling by neutralizing IL-6 receptor α (IL-6r, CD126) have decreased atherosclerosis and inflammation within the lesions, blood and other organs as gauged in part by single-cell RNA sequencing (scRNA-seq). We further hypothesize that IL-6r inhibition will limit expansion of the mutant clone. Specific aim 2 will probe the role of classical vs. trans IL-6 signaling in myeloid cells in accelerated atherogenesis in CHIP using Il6rflox/flox/Lyz2-Cre mice bone marrow chimeric LDLR-/- mice (to block leukocyte classical signaling), and administration of a gp130-IgG1-Fc chimeric protein (to block trans signaling) using similar procedures and endpoints. The results will illuminate the controversy and unsettled science regarding the contributions of classical and trans IL-6 signaling to atherogenesis. Specific aim 3. Our preliminary experiments show that female myeloidTet2-/-Ldlr-/- mice have greater acceleration of atherogenesis than Tet2+/+ Ldlr-/- male mice and, unlike their male counterparts, show reduced atherogenesis with IL-1β neutralization. We will localize where this sex difference operates in the inflammasome–IL-1β–IL-6 pathway, and test the hypothesis that female Dnmt3a-/-Ldlr-/- mice have greater response to IL-6r inhibition than males. We will probe mechanisms by gonadal ablation experiments and by analysis of scRNA-seq data, which in preliminary data shows IL-1β expression in resident macrophages cells from atheroma from Tet2-/- females but not males. This work will deepen understanding of the mechanisms of accelerated atherosclerosis in CHIP. Our new pilot clinical data show that an anti-IL-6 antibody can mute inflammation in humans. Thus, the work proposed here will provide an indispensable step toward validating and furnishing the fundamental basis of an immediately translatable targeted therapeutic strategy based on CHIP genotype.