Mechanisms by which clonal haematopoiesis of indeterminate potential (CHIP)-driver mutations confer cardiovascular risk

克隆性造血潜能不确定(CHIP)的特征是存在携带体细胞突变的扩增血细胞克隆，最常见的是表观遗传修饰基因DNMT3A或TET2，它们与发生血液系统恶性肿瘤的风险增加10倍相关。然而，芯片驱动突变携带者死亡率的增加在很大程度上是由心血管疾病而不是白血病决定的。我们的初步数据显示，在我们医院接受冠状动脉造影术的患者中，CHIP的患病率是普通人群的三倍。CHIP增加心血管风险的分子和细胞机制尚不明确，主要依赖于转基因小鼠的实验模型。我们假设，芯片驱动基因的基因组突变通过调控基因转录和翻译的表观遗传修饰来重新编程单核/巨噬细胞机制，从而导致细胞命运改变，引发心血管系统的慢性炎症。为了弥合这一知识差距，我们建立了一项协议，从同一细胞中并行对基因组DNA和信使RNA进行测序，并将通过对人IPSC来源的单核细胞和巨噬细胞进行碱基编辑来建立体外芯片克隆，以进行多组学分析。综上所述，我们拟议的工作将揭示芯片驱动突变引起的DNA甲基化变化、转录失调和细胞功能改变之间的机制联系，为确定芯片驱动的心血管疾病的特定治疗靶点奠定基础。

Clonal haematopoiesis of indeterminate potential (CHIP) is characterized by the presence of an expanded blood cell clone carrying somatic mutations, most commonly in epigenetic modifier genes DNMT3A or TET2, which are associated with a ten times higher risk for developing haematological malignancies. Yet, increased mortality in carriers of CHIP-driver mutations is largely determined by cardiovascular disease rather than leukaemia. Our preliminary data show that in patients undergoing coronary angiography in our hospital, CHIP is three times more prevalent compared to the general population. The molecular and cellular mechanisms by which CHIP increases cardiovascular risk are ill-defined, and mainly rely on experimental models in transgenic mice. We hypothesize that genomic mutation in CHIP-driver genes reprograms the monocyte/macrophage machinery via epigenetic modification that regulates gene transcription and translation, leading to an altered cell fate triggering chronic inflammation in the cardiovascular system. To close the knowledge gap, we established a protocol to sequence genomic DNA and messenger RNA in parallel from the same cell, and will model CHIP clones in vitro by base-editing human iPSC-derived monocytes and macrophages for multi-omic analysis. Taken together, our proposed work will unveil mechanistic links between CHIP-driver mutation induced DNA methylation changes, transcriptional dysregulation and altered cell function, laying the foundation for identifying specific therapeutic targets in CHIP-driven cardiovascular disease.