Mosaic: post-zygotic mutations in vascular malformations

项目总结 动脉、静脉、毛细血管和淋巴管的形态发生缺陷导致血管 畸形，一种比较常见的先天性畸形。目前的治疗方法主要是侵入性的，可以 会产生严重的发病率。大多数血管畸形是由于合子后(嵌合体)激活所致。 PI3K-AKT和RAS-MAPK通路中几个癌基因(PIK3CA、KRAS、MAP2K1等)的突变。 这些突变从来不存在于来自白细胞的DNA中，这是最常见的 基因检测，使分子诊断具有挑战性。 从长远来看，我们的目标是改善血管畸形患者的治疗。建议数 实验通过扩大对VM患者的诊断选择并解剖细胞和 血管畸形的空间异质性，使用新的尖端技术。 我们的第一个目标是确定血浆来源的无细胞dna的非侵入性“液体活检”是否能检测到 血管畸形患者的嵌合体突变。由于突变导致血管畸形 通常只存在于畸形本身，目前需要进行侵入性手术或活检 诊断。由于需要分子诊断来指导靶向药物治疗(如PI3K或AKT 抑制剂，其临床试验目前正在开放)，开发血管的非侵入性诊断 畸形会对病人产生直接影响。 接下来，我们将研究血管畸形组织中单细胞基因表达的变化。 使用一种新的多组学方法，将这些信息与每个细胞的突变状态相结合。我们还将使用 使我们能够可视化基因表达如何在二维和三维空间内变化的技术 血管畸形。由于通常只有一小部分(1-10%)血管畸形内的细胞 拥有驱动突变，这些实验将帮助我们理解小细胞群体如何 产生巨大的多细胞畸形。 我们组建了一个专业领域互不重叠的多学科团队，以实现这些目标 目标。我们的实验将使用一个大型的、预先存在的血管生物储存库的样本进行。 畸形标本含有丰富的临床数据。我们希望这项工作将扩大我们对血管的理解 特别是畸形和血管生物学，以及更普遍的嵌合体的性质。

PROJECT SUMMARY Defective morphogenesis of arteries, veins, capillaries, and lymphatic vessels results in vascular malformations, a relatively common congenital malformation. Current therapies are primarily invasive and can produce significant morbidity. Most vascular malformations are due to post-zygotic (mosaic) activating mutations in a few oncogenes (PIK3CA, KRAS, MAP2K1, others) in the PI3K-AKT and RAS-MAPK pathways. These mutations are never present in DNA derived from white blood cells, the most common sample for genetic testing, making molecular diagnosis challenging. Long-term, our goal is to improve treatment of individuals with vascular malformations. The proposed experiments advance that goal by expanding diagnostic options for VM patients and dissecting cellular and spatial heterogeneity in vascular malformations, using novel, cutting edge technologies. Our first aim is to determine if non-invasive “liquid biopsies” of plasma derived cell-free DNA can detect mosaic mutations in individuals with vascular malformations. Since mutations driving vascular malformations are typically present only in the malformation itself, an invasive surgery or biopsy is currently required for diagnosis. Since a molecular diagnosis is required to guide targeted drug therapies (such as PI3K or AKT inhibitors, for which clinical trials are currently open), developing non-invasive diagnostics for vascular malformations would have immediate patient impact. Next, we will study how gene expression changes in single cells in vascular malformation tissues and integrate this information with each cell's mutation status, using a novel, multi-omics method. We will also use techniques that allow us to visualize how gene expression changes in two and three dimensional space within vascular malformations. Since only a small fraction (1-10%) of cells inside vascular malformations typically possess the driving mutation, these experiments will help us understand how small cell populations can produce large, multicellular malformations. We have assembled a multidisciplinary team with non-overlapping areas of expertise to accomplish these goals. Our experiments will be performed using samples from a large, pre-existing biorepository of vascular malformation samples rich in clinical data. We expect this work to expand our understanding of vascular malformations and vascular biology specifically, and the nature of mosaicism more generally.