Selective mRNA translation in developmental disorders

发育障碍中的选择性 mRNA 翻译

• 批准号: 10413944
• 负责人: Slobodan Beronja
• 金额: $ 9.48万
• 依托单位: FRED HUTCHINSON CANCER CENTER
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-06-18 至 2023-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10413944
• 关键词: Selective; mRNA; translation; developmental; disorders; Selective; mRNA; translation; developmental; disorders

Abstract RASopathies cause the majority of congenital disorders affecting nearly 1 in 1000 individuals. In particular, mutations in RAS-MAPK pathway genes lead to distinct pathologies including craniofacial dysmorphology, mental impairment, musculoskeletal defects, and a predisposition to cancer. Although presentations may vary between different mutations, nearly all RASopathies share common skin growth abnormalities. At a genetic level, germline mutations to RAS pathway members including Hras and Kras are known to cause these defects which are best exemplified by Costello, Noonan, and Cardiofaciocutaneous syndromes. For years, comprehensive interrogation of RAS in development has been limited to genome-wide studies of DNA and RNA. While important, these investigations have left translation-based mechanisms largely untouched. This is remarkable in light of emerging evidence that developmental disorders, such as Diamond-Blackfan Anemia and Schwachman-Diamond and Treacher Collins syndromes (reviewed in Tahmasebi et al., 2018), are causally linked to impairments in the translation apparatus. Thus, our current knowledge of the mechanistic basis of RASopathies is incomplete, which is a barrier to therapeutic innovation. Our long-term goal is to uncover the mechanism of Ras-mediated tissue growth, which will ultimately yield innovative therapies to restore normal tissue homeostasis without compromising housekeeping functions during development. Using skin as a defined model of tissue development we have discovered that hyperactive Hras simultaneously drives specialized proliferation and differentiation programs by rewiring the translation initiation machinery through eIF2B5. Utilizing state-of-the-art in vivo genetic screens pioneered in our laboratory, we have determined the regulon of genes that eIF2B5 governs to impact self-renewal and cell fate choice. Remarkably, these mRNA networks are clearly demarcated by their function with ubiquitination emerging as a key regulator of cellular differentiation. As such, we hypothesize that activation of Ras promotes translation of a subset of mRNAs that support non-physiological tissue growth during development, where increased stem cell proliferation is balanced by their loss through differentiation into post-mitotic progeny. In this proposal we will use a confluence of in vivo models, intra-vital microscopy, and newly developed cellular and molecular assays to delineate how the interplay between RAS and eIF2B5 influences tissue dynamics. We will accomplish the following Aims: 1) Uncover how eIF2B5-dependent ubiquitin ligases directs progenitor renewal and fate choice; and 2) Elucidate how activated Hras and eIF2B5 direct mRNA specific translation to regulate progenitor renewal. Collectively, the successful completion of our Aims will provide a new understanding of cellular and molecular principles that support Ras-driven non-physiological growth during development. Ultimately, these new insights will inform the development of novel therapeutics, which can differentially inhibit the pathologic impact of Ras mediated tissue imbalance while maintain homeostasis which is essential for life.

抽象的 rasopathies导致大多数影响近1000名患者的先天性疾病。尤其， RAS-MAPK途径基因中的突变导致不同的病理，包括颅面畸形， 精神障碍，肌肉骨骼缺陷和癌症的易感性。尽管演讲可能会有所不同 在不同的突变之间，几乎所有的ras病都有常见的皮肤生长异常。在遗传上 水平，已知包括HRA和KRA在内的RAS途径成员的种系突变会导致这些缺陷 最好用Costello，Noonan和Cardiofaciociatanous综合征来体现。多年来， 对RAS开发中RA的全面询问仅限于全基因组的DNA和 RNA。尽管很重要，但这些研究使基于翻译的机制在很大程度上没有受到影响。这是 鉴于新兴的证据表明发育障碍，例如钻石 - 黑人贫血 以及Schwachman-Diamond和Treacher Collins综合征（在Tahmasebi等人，2018年进行了评论），是 与翻译机构中的损害有因果关系。因此，我们当前对机械的知识 消除病是不完整的，这是治疗创新的障碍。我们的长期目标是 发现RAS介导的组织生长的机制，最终将产生创新的疗法 恢复正常的组织稳态，而不会在发育过程中损害家政功能。使用 皮肤作为组织开发的定义模型，我们发现同时过度活跃的HRA 通过重新布线翻译启动机械来驱动专业的扩散和差异化计划 通过EIF2B5。利用在我们实验室开创的体内遗传筛选中，我们有 确定了EIF2B5控制自我更新和细胞命运选择的基因的调节。值得注意的是 这些mRNA网络清楚地通过泛素化作为关键调节剂的泛素化功能来划分 细胞分化。因此，我们假设RAS的激活促进了一部分的翻译 支持在发育过程中非生理组织生长的mRNA，其中干细胞增加 通过分化为有丝分裂后后代的损失，增殖是平衡的。在这个建议中，我们将 使用体内模型，重要内显微镜以及新开发的细胞和分子测定的汇合 描绘RAS和EIF2B5之间的相互作用如何影响组织动力学。我们将完成 以下目的：1）发现依赖EIF2B5的泛素连接酶如何指导祖细胞更新和命运选择； 2）阐明如何激活的HRA和EIF2B5直接mRNA特异性翻译以调节祖细胞 更新。总体而言，我们的目标的成功完成将提供对蜂窝的新理解和 在开发过程中支持RAS驱动的非生理生长的分子原理。最终，这些 新的见解将为新型治疗学的发展提供信息，这可以差异地抑制病理学 RAS介导的组织失衡的影响，同时保持体内平衡，这对生命至关重要。