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

基本信息

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
项目类别：
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

项目摘要

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.

项目概要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）是其中的主要原因。最常见的结构性出生缺陷，每年影响约 40,000 名先天性心脏病婴儿。死亡率和发病率的负担是由“严重”先心病引起的，定义为需要手术或治疗的疾病导致严重先心病的分子机制尚不完全。理解，阻碍了预防、诊断和治疗的进展。人类出生登记显示，严重先天性心脏病与异型性、基因缺陷之间存在显着关联。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、人类遗传学和先心病，我们发现了一种新的细胞表面泛素化途径（“MMM 途径”）在发育过程中的组织模式中发挥广泛作用。该通路的破坏会导致胚胎中出现严重先心病的特征性异位综合征。小鼠，以及其他组织的缺陷，例如四肢、骨骼和面部。 MMM 突变胚胎的心内解剖结构重建也揭示了严重先心病的存在常见于人类患者，包括右心室双出口和大动脉转位。 MMM 通路通过由 MEGF8 组成的受体样泛素连接酶复合物锚定在细胞表面，一种单次跨膜蛋白，以及 MGRN1（一种 RING 超家族 E3 连接酶）。膜束缚的泛素化机器通过标志性的刺猬 (Hh) 途径减弱信号传导。从机制上讲，MMM 组件通过以下方式降低了 Hh 传感器平滑 (SMO) 的丰度：直接泛素化，降低靶细胞对 Hh 配体的敏感性，从而我们建议测试。假设 MMM 通路作为信号受体的交通控制系统，调节我们的首要目标是了解左右模式和心脏发育。 MOSMO 的功能和发育作用，一种未表征的四跨膜蛋白确定为 MMM 途径的第三个组成部分在第二个目标中，我们测试异源性和 MMM 突变胚胎中出现的先天性心脏病 (CHD) 是由关键时期 Hh 信号强度升高引起的。开发并寻找受 MMM 途径调节的其他信号受体。利用我们针对 MMM 蛋白的全面生化和发育测定来测试其功能在患有严重先天性心脏病的人类患者中发现了罕见的 MMM 基因编码变异，成功完成了这一任务。该项目将揭示长期观察到的左右之间联系背后的贩运和信号机制模式和心脏发育，从而增进我们对分子的理解严重冠心病的病理生理学。