U2AF1 mutations in myelodysplastic syndromes: from mechanism to therapy

描述（由申请人提供）：骨髓增生异常综合征（MDS）是一组异质性血液疾病，其特征是无效和发育不良的造血。MDS的有效治疗方法很少，部分原因是我们对这种疾病的分子基础不完全了解。最近发现的影响MDS中RNA剪接机制的高频突变为我们进一步了解MDS生物学和开发新疗法提供了重要机会。然而，剪接体突变的分子后果是未知的，阻碍了努力了解这些突变如何有助于造血发育不良，并导致新的治疗机会。为了解决这一知识差距，我们建议确定影响剪接体基因U2AF1（MDS中最常见的突变基因之一）的突变的机制、功能和治疗后果。我们已经建立了一个在RNA剪接机制和基于剪接的疗法（布拉德利）以及MDS生物学和患者护理（Ramakrishnan，Shimamura）方面具有经验的团队。在目标1中，我们将确定MDS相关突变如何改变U2AF1在3'剪接位点识别中的正常作用，包括引起U2AF1：RNA相互作用中的序列特异性改变。在目标2中，我们将鉴定在具有U2AF1突变的细胞中错误剪接并随后翻译成蛋白质的mRNA，并测试U2AF1突变引起MDS细胞的分子标志的假设。在目标3中，我们将检验剪接位点识别的化学抑制将选择性地杀死具有U2AF 1突变的细胞的假设。在本研究的结论中，我们将确定U2AF1突变对剪接过程的机制后果，显示这些突变如何有助于MDS细胞的分子病理学特征，并测试靶向RNA剪接过程本身作为MDS新治疗途径的潜力。最终，我们希望拟议的工作能够加快开发新疗法治疗MDS的步伐。

DESCRIPTION (provided by applicant): Myelodysplastic syndromes (MDS) are a heterogeneous group of blood disorders characterized by ineffective and dysplastic hematopoiesis. There are few effective treatments for MDS, due in part to our incomplete understanding of the molecular basis of this disease. The recent discovery of high-frequency mutations affecting the RNA splicing machinery in MDS presents a significant opportunity to further our knowledge of MDS biology and inform the development of new therapeutics. However, the molecular consequences of spliceosomal mutations ARE unknown, hindering efforts to understand how these mutations contribute to dysplastic hematopoiesis and lead to new therapeutic opportunities. To address this gap in knowledge, we propose to determine the mechanistic, functional, and therapeutic consequences of mutations affecting the spliceosomal gene U2AF1, one of the most commonly mutated genes in MDS. We have built a team with experience in RNA splicing mechanisms and splicing-based therapeutics (Bradley), as well as MDS biology and patient care (Ramakrishnan, Shimamura). In Aim 1, we will determine how MDS-associated mutations alter U2AF1's normal role in 3' splice site recognition, including causing sequence-specific alterations in U2AF1:RNA interactions. In Aim 2, we will identify mRNAs that are mis-spliced in cells with U2AF1 mutations and subsequently translated into protein, and test the hypothesis that U2AF1 mutations give rise to molecular hallmarks of MDS cells. In Aim 3, we will test the hypothesis that chemical inhibition of splice site recognition wil selectively kill cells with U2AF1 mutations. At the conclusion of this study, we will have determined the mechanistic consequences of U2AF1 mutations for the splicing process, shown how these mutations contribute to molecular pathologies characteristic of MDS cells, and tested the potential of targeting the RNA splicing process itself as a new therapeutic avenue for MDS. Ultimately, we expect the proposed work to accelerate the pace at which new therapeutics may be developed to treat MDS.