Gene X Environment Interactions in the Pathogenesis of Uterine Fibroids

摘要 子宫肌瘤（UFs）是发生在子宫肌层的单克隆肿瘤，是最常见的肿瘤。 育龄妇女常见肿瘤。越来越多的证据表明， UFs起源于子宫肌层中异常干细胞的假说。我们现在已经确认 Stro-1 +/CD44+子宫肌层干细胞（MSC），能够自我更新和再生， 子宫肌层组织，其在动物模型中引起UF。我们有能力识别和 分离这些MSC，我们处于独特的位置，以解决风险因素如何影响UF 细胞的起源，以启动和促进这些肿瘤的发展。 像许多疾病一样，有充分的证据表明，环境暴露和遗传因素 改变有助于UF发病机制。我们和其他人已经证明早期生命 环境暴露于内分泌干扰化合物（EDCs）会增加UF风险， 诱导表观基因组的发育重编程。这种表观基因组重编程 涉及改变染色质结构的组蛋白和DNA甲基化模式的变化， 基因转录，并在生命早期诱导，持续到成年。的遗传变异所 mediator 12（MED12）和tuberous sclerosis complex 2（TSC2）肿瘤抑制因子， 分别在人类和啮齿动物模型中发展UF肿瘤。有趣的是，MED12 和TSC 2缺陷共享一个共同的下游效应子：β-连环蛋白信号传导的激活， TCF/LEF基因表达的反式激活。 我们以前无法询问UFs的起源细胞，这限制了我们对UFs的理解。 基因：环境相互作用（GxE）如何影响UF风险。现在我们可以分离和侧写 我们第一次能够克服这一关键障碍， 这一重要疾病的风险决定因素。在这个应用程序中，我们将利用我们新发现的 分离和询问MSC的能力，并应用最新的见解如何环境 暴露重新编程表观基因组，探索GxE相互作用，促进 UFs的起源细胞中的肿瘤发生。 具体目标1：检验β-连环蛋白信号传导的激活是一种常见的 基因改变的效应子途径。在这个机械的目的，我们将测试 假设在MSC中，MED12突变（人）或Tsc 2缺失（大鼠）导致改变的 转录谱的特征在于增加的TCF/LEF反式激活基因表达。 具体目标2：检验发育期EDC暴露导致表观遗传性 与MSC/TIC中的遗传缺陷合作的重编程。在这个机械的目标中， 我们将描述EDC诱导的表观基因组重编程，并测试假设， TCF/LEF靶基因的重编程在β-catenin被激活时加剧了它们的表达。 在rMSC和肿瘤起始细胞（TIC）中活化。 具体目标3：检验与高与低UF风险相关的MSC表现出 表观遗传组蛋白修饰的差异。在这个翻译的目的，我们将探讨 MSC表观遗传模式与UF风险之间的关系，使用从正常人分离的MSC 无UF女性的子宫肌层（MyoN）和UF女性的高危子宫肌层 （MyoF）。由于表观基因组改变是潜在的可逆性，我们还将测试 假设降低UF风险的干预措施是通过减少MSC数量和/或 将MSC表观基因组"重置"回低风险概况。 影响：我们的工作解决了NIH定义的几个知识差距和优先研究领域 包括;干/祖细胞在妇科健康和疾病，跨学科研究 妇科疾病中的“组学”。重要的是，这也将是GxE的首次探索 在UF的起源细胞中驱动疾病的相互作用。

Abstract Uterine Fibroids (UFs) are monoclonal tumors arising in the myometrium, and are the most common tumor of reproductive age women. An increasing body of evidence supports the hypothesis that UFs originate from aberrant stem cells in the myometrium. We have now identified a Stro-1+/CD44+ myometrial stem cell (MSC) capable of self-renewal and regeneration of myometrial tissues, which gives rise to UFs in animal models. With our ability to identify and isolate these MSCs, we are in a unique position to address how risk factors impact the UF cell-of-origin to initiate and promote the development of these tumors. Like many diseases, there is ample evidence that both environmental exposures and genetic alterations contribute to UF pathogenesis. We, and others have shown that early life environmental exposures to endocrine disrupting compounds (EDCs) increase UF risk by inducing developmental reprogramming of the epigenome. Such epigenomic reprogramming involves changes in histone and DNA methylation patterns that alter chromatin architecture and gene transcription, and when induced in early life, persist into adulthood. Genetic alterations in mediator 12 (MED12) and the tuberous sclerosis complex 2 (TSC2) tumor suppressor, drive development of UF tumors in both humans and rodent models, respectively. Interestingly, MED12 and TSC2 defects share a common downstream effector: activation of β-catenin signaling and TCF/LEF transactivation of gene expression. Our previous inability to interrogate the cells-of-origin for UFs has limited our understanding of how gene:environment interactions (GxE) influence UF risk. Now that we can isolate and profile MSCs, we are for the first time in a position to overcome this critical barrier to understanding determinants of risk for this important disease. In this application we will utilize our new-found ability to isolate and interrogate MSCs, and apply recent insights on how environmental exposures reprogram the epigenome, to explore GxE interactions that promote tumorigenesis in the cell-of-origin for UFs. Specific Aim 1: Test the hypothesis that activation of β-catenin signaling is a common effector pathway for genetic alterations that drive UFs. In this mechanistic Aim, we will test the hypothesis that in MSCs, MED12 mutation (human) or loss of Tsc2 (rat) results in an altered transcriptional profile characterized by increased TCF/LEF transactivation of gene expression. Specific Aim 2: Test the hypothesis that developmental EDC exposure results in epigenetic reprogramming that cooperates with genetic defects in MSC/TICs. In this mechanistic Aim, we will characterize EDC-induced reprogramming of the epigenome, and test the hypothesis that reprogramming of TCF/LEF target genes exacerbates their expression when β-catenin is activated in rMSCs and in tumor initiating cells (TICs). Specific Aim 3: Test the hypothesis that MSCs associated with high vs low UF risk exhibit differences in epigenetic histone modifications. In this translational Aim, we will explore the relationship between MSC epigenetic patterns and UF risk using MSCs isolated from normal myometrium of women without UFs (MyoN) and at-risk myometrium from women with UFs (MyoF). Because epigenomic alterations are potentially reversable, we will also test the hypothesis that an intervention that reduces UF risk does so by decreasing MSC number and/or “resetting” the MSC epigenome back to a low risk profile. Impact: Our work address several knowledge gaps and priority research areas as defined by NIH including; Stem/Progenitor Cells in Gynecologic Health and Disease, Transdisciplinary Research and '–Omics' in Gynecologic Disorders. Importantly, it will also be the first exploration of GxE interactions that drive disease in the cells of origin for UFs.