A protein traffic control system that regulates left-right patterning and heart development

调节左右模式和心脏发育的蛋白质交通控制系统

• 批准号: 10181808
• 负责人: Teresa M Gunn
• 金额: $ 75.67万
• 依托单位: STANFORD UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-09-01 至 2025-08-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10181808
• 关键词: 3-Dimensional; Affect; Alleles; Anatomy; Attenuated; Biochemical; Biological Assay; Birth; Blood Vessels; CRISPR screen; Cardiac development; Cell Communication; Cell surface; Cells; Characteristics; Clustered Regularly Interspaced Short Palindromic Repeats; Code; Complex; Congenital Abnormality; Congenital Heart Defects; Data; Defect; Development; Diagnostic; Double Outlet Right Ventricle; Embryo; Erinaceidae; Face; Foundations; Functional disorder; Genes; Genetic; Genetic Predisposition to Disease; Heart; Heart Abnormalities; Human; Human Genetics; Inheritance Patterns; Integral Membrane Protein; Left; Life; Ligands; Limb structure; Link; Live Birth; Membrane; Membrane Proteins; Modeling; Molecular; Morbidity - disease rate; Morphogenesis; Mus; Mutation; Operative Surgical Procedures; Organ; Outcome; Pathogenicity; Pathway interactions; Patients; Pattern; Penetrance; Pharmacology; Phenocopy; Play; Procedures; Proteins; Proteomics; Receptor Signaling; Registries; Research Personnel; Role; Side; Signal Transduction; Situs Inversus; Skeleton; Structural Congenital Anomalies; Syndrome; System; Testing; Therapeutic; Tissues; Transducers; Transposition of Great Vessels; Ubiquitination; United States; Variant; Visceral; base; cardiogenesis; cohort; congenital heart disorder; critical developmental period; critical period; exome sequencing; genetic architecture; genetic testing; genome-wide; in vitro Assay; infant death; mortality; mouse development; mouse genetics; mouse model; mutant; novel; novel diagnostics; receptor; reconstruction; smoothened signaling pathway; stillbirth; trafficking; ubiquitin ligase; ubiquitin-protein ligase

Project Summary A protein traffic control system that regulates left-right patterning and heart development Structural birth defects represent the leading cause of infant deaths. Congenital Heart Defects (CHDs) are the most common structural birth defects, affecting ~40,000 babies each year. Amongst CHDs, a disproportionate burden of mortality and morbidity is due to “severe” CHDs, defined as those that require surgery or a procedure before the first year of life. The molecular mechanisms that drive severe CHDs are incompletely understood, hampering preventative, diagnostic and therapeutic advances. Data from mouse studies and human birth registries have revealed a striking association between severe CHDs and heterotaxy, defects in left-right patterning of visceral organs. By integrating the expertise of three investigators in signal transduction, mouse development, human genetics and CHDs, we have identified a novel cell-surface ubiquitination pathway (the “MMM pathway”) that plays widespread roles in the patterning of tissues during development. Disruption of this pathway leads to a characteristic syndrome of heterotaxy with severe CHDs in embryonic mice, along with defects in other tissues such as the limb, skeleton and face. Three dimensional reconstructions of the intracardiac anatomy of MMM mutant embryos reveal the presence of severe CHDs also often seen in human patients, including double outlet right ventricle and transposition of the great arteries. The MMM pathway is anchored at the cell surface by a receptor-like ubiquitin ligase complex composed of MEGF8, a single-pass transmembrane protein, and MGRN1, a RING superfamily E3 ligase. This unique membrane-tethered ubiquitination machine attenuates signaling through the iconic Hedgehog (Hh) pathway. Mechanistically, the MMM components decrease the abundance of the Hh transducer Smoothened (SMO) by direct ubiquitination, thereby reducing the sensitivity of target cells to Hh ligands. We propose to test the hypothesis that the MMM pathway functions as a traffic control system for signaling receptors that regulate left-right patterning and cardiac development. Our first aim is focused on understanding the biochemical function and developmental roles of MOSMO, an uncharacterized tetraspan membrane protein that we identified as a third component of the MMM pathway. In the second aim, we test whether the heterotaxy and CHDs seen in MMM mutant embryos are caused by elevated Hh signaling strength at critical periods in development and also search for other signaling receptors regulated by the MMM pathway. Finally, we leverage our comprehensive biochemical and developmental assays for MMM proteins to test the functionality of rare coding variants in MMM genes seen in human patients with severe CHDs. Successful completion of this project will uncover trafficking and signaling mechanisms that underlie the long-observed link between left-right patterning and heart development and consequently advance our understanding of the molecular pathophysiology of severe CHDs.

项目摘要 一个调节左右模式和心脏发育的蛋白质交通控制系统 结构性出生缺陷是婴儿死亡的主要原因。先天性心脏病（CHD）是 最常见的结构性出生缺陷，每年影响约4万名婴儿。在冠心病中， 死亡率和发病率的负担是由于“严重”CHD，定义为那些需要手术或 在生命的第一年之前。驱动严重冠心病的分子机制是不完全的 这阻碍了预防、诊断和治疗的进步。来自小鼠研究的数据， 人类出生登记显示，严重CHD与异位症、先天性心脏病缺陷、 内脏器官的左右模式。通过整合三位研究人员在信号转导方面的专业知识， 小鼠发育，人类遗传学和CHD，我们已经确定了一种新的细胞表面泛素化 MMM通路（“MMM通路”），其在发育期间的组织图案化中发挥广泛作用。 这一通路的中断导致胚胎期先天性心脏病（CHD）的特征性异位综合征。 小鼠，沿着在其他组织如肢体、骨骼和面部有缺陷。三维 MMM突变胚胎心内解剖结构的重建揭示了严重CHD的存在， 常见于人类患者，包括右心室双出口和大动脉转位。的 MMM途径通过由MEGF8组成的受体样泛素连接酶复合物锚定在细胞表面， 一种单程跨膜蛋白，和MGRN1，一种RING超家族E3连接酶。这种独特 膜系泛素化机器通过标志性的Hedgehog（Hh）途径减弱信号传导。 在机械上，MMM组分通过以下方式降低Hh传感器平滑（SMO）的丰度： 直接泛素化，从而降低靶细胞对Hh配体的敏感性。我们建议测试 假设MMM通路作为信号受体的交通控制系统发挥作用， 左右模式和心脏发育。我们的第一个目标是了解生物化学 MOSMO是一种未鉴定的四膜蛋白， 被鉴定为MMM途径的第三组分。在第二个目标，我们测试是否异位和 在MMM突变胚胎中观察到的CHDs是由Hh信号强度在关键时期升高引起的， 并寻找由MMM途径调节的其他信号受体。最后我们 利用我们对MMM蛋白质的全面生化和发育分析来测试功能性 MMM基因中罕见的编码变异在患有严重CHD的人类患者中观察到。成功完成本 该项目将揭示长期观察到的左右之间联系的贩运和信号机制 模式和心脏发育，从而促进我们对分子的理解， 严重CHD的病理生理学。