Pathological reprogramming of the m6A epitranscriptome in uterine fibroids

项目总结/摘要 子宫肌瘤（UFs）是世界范围内对妇女健康最重要的良性肿瘤威胁。因为不再- 目前存在UFs长期非侵入性治疗选择，深入了解肿瘤病因是开发的关键 更有效的治疗方法。在这方面，虽然UFs的表观/遗传决定因素已被表征， 尽管如此，其潜在的发病机制仍不清楚，涉及疾病的其他因素， 发病在此，我们提出了一个新的基础来解释UF的发展，通过病理重编程的细胞， 子宫肌层表转录组，并提供使用肿瘤发生抑制剂的治疗性干预的概念证明 增强子活性由未预料到的m6 A-染色质串扰驱动。作为体内最丰富的化学物质 在mRNA的修饰中，N6-甲基腺苷（m6 A）是转录后mRNA命运的关键决定因素， 从而确定细胞的身份和功能。因此，m6 A稳态的破坏涉及多种多样的免疫调节。 慢性和急性人类疾病状况。然而，关于m6 A在肿瘤中的作用还不清楚。 UFs的发病机制。我们现在发现m6 A writers L3和RBM 15在UFs中异常上调， 与相邻的子宫肌层（MM）相比。此外，我们表明，胃L3耗竭触发UF细胞死亡， 转录抑制性组蛋白甲基化的整体上调，首次将m6 A与UF肿瘤联系起来 生物学和揭示其新的串扰与UF表观基因组。整合的RNA甲基化和表达 在缺乏胃L3的UF细胞中的分析揭示了一个深刻改变的m6 A修饰景观，并确定了 胃L3驱动的UF细胞生长和存活的高置信度m6 A修饰的mRNA效应物。基于这些 研究结果，我们假设异常的胃L3依赖性RNA甲基化重新编程MM 表观转录组，导致表观遗传失调和改变的基因表达，驱动UF启动和 进展因此，我们提出，表观遗传抑制剂，通过抑制m6 A驱动的前- 致瘤途径，将为UF提供治疗益处。为了验证这些假设，我们将：（1）建立 UFs中表转录组重编程的基础。我们将比较分析m6 a改装景观 来自配对MM和UF肿瘤组织的mRNA和染色体相关调控RNA（carRNA）， 研究胃L3和RBM 15在甲基化重编程中的功能协同性;（2）描述胃L3和RBM 15在甲基化重编程中的功能协同性 胃L3依赖性RNA甲基化在纤维化转化中的作用。我们会问，在某种程度上， 依赖于它的过表达和甲基转移酶活性，可以触发MM干细胞转化， （3）阐明胃L3依赖性RNA甲基化对基因表达的影响， 在UFs中表达。我们将评估m6 A对mRNA稳定性和翻译以及carRNA的全球影响。 染色质状态和转录的依赖性控制;（4）检查BRD抑制剂的治疗潜力 在人类UF的临床前小鼠模型中。我们将评估选择的BRD抑制剂的治疗效果， 安全性和抗肿瘤活性的机制，包括对染色质状态和转录的影响。

PROJECT SUMMARY/ABSTRACT Uterine fibroids (UFs) are the most important benign neoplastic threat to women’s health worldwide. As no long- term non-invasive treatment option currently exists for UFs, deeper insight into tumor etiology is key to develop more effective therapies. In this regard, while the epi/genetic determinants of UFs have been characterized extensively, their underlying pathogenesis nonetheless remains obscure, implicating additional factors in disease onset. Herein, we propose a novel basis to explain UF development through pathological reprogramming of the myometrial epitranscriptome and offer proof of concept for therapeutic intervention using inhibitors of tumorigenic enhancer activity driven by unanticipated m6A-chromatin crosstalk. As the most abundant internal chemical modification in mRNA, N6-methyladenosine (m6A) is a key determinant of posttranscriptional mRNA fate and thus cell identity and function. Accordingly, disruption of m6A homeostasis is implicated in a diverse range of chronic and acute human disease conditions. However, nothing is known about the role of m6A in the pathogenesis of UFs. We now show that m6A writers METTL3 and RBM15 are aberrantly upregulated in UFs compared to adjacent myometrium (MM). Further, we show that METTL3 depletion triggers UF cell death and global upregulation of transcriptionally repressive histone methylation, linking m6A for the first time with UF tumor biology and revealing its novel crosstalk with the UF epigenome. Integrated RNA methylation and expression profiling in METTL3-deficient UF cells revealed a profoundly altered m6A modification landscape and identified high-confidence m6A-modified mRNA effectors of METTL3-driven UF cell growth and survival. Based on these findings, we hypothesize that aberrant METTL3-dependent RNA methylation reprograms the MM epitranscriptome, leading to epigenetic dysregulation and altered expression of genes that drive UF initiation and progression. Accordingly, we propose that epigenetic inhibitors, through suppression of m6A-driven pro- tumorigenic pathways, will provide therapeutic benefit in UFs. To test these hypotheses we will: (1) Establish the basis of epitranscriptomic reprogramming in UFs. We will comparatively profile the m6A modification landscape of mRNAs and chromosome-associated regulatory RNAs (carRNAs) from paired MM and UF tumor tissues and investigate functional cooperativity between METTL3 and RBM15 in methylomic reprogramming; (2) Delineate the role of METTL3-dependent RNA methylation in fibrotic transformation. We will ask if METTL3, in a manner dependent upon its overexpression and methyltransferase activity, can trigger MM stem cell transformation in vitro and UF tumor formation in vivo; (3) Elucidate the impact of METTL3-dependent RNA methylation on gene expression in UFs. We will assess the global impact of m6A on mRNA stability and translation as well as carRNA- dependent control of chromatin state and transcription; (4) Examine the therapeutic potential of BRD inhibitors in a preclinical mouse model of human UFs. We will evaluate select BRD inhibitors for therapeutic efficacy, safety, and mechanism of anti-tumor activity, including impact on chromatin status and transcription.