Elucidating the transcriptional mechanisms that control the expression of the SARS-CoV-2 receptor ACE2

阐明控制 SARS-CoV-2 受体 ACE2 表达的转录机制

基本信息

批准号：
10179069
负责人：
Jian Xu
金额：
$ 44.15万
依托单位：
UT SOUTHWESTERN MEDICAL CENTER
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：
2021-07-01 至 2023-06-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10179069
关键词：
2019-nCoV ACE2 Affinity Affinity Chromatography Binding Biochemical Biological Assay COVID-19 COVID-19 pandemic COVID-19 pathogenesis COVID-19 treatment Cells Chromatin Clustered Regularly Interspaced Short Palindromic Repeats Complex Coronavirus Development Disease Distal Enhancers Epigenetic Process Epithelial Cells Event Genes Genetic Genetic Enhancer Element Genetic Transcription Goals Gonadal Steroid Hormones Human Infection Inflammation Inflammatory Integration Host Factors Knowledge Lung Mediating Membrane Fusion Methods Molecular Molecular Target Mus Pathogenesis Pathologic Pathology Pathway interactions Pharmacology Physiological Predisposition Preventive therapy Proteins Regulation Regulatory Element Renin-Angiotensin System Reporter Resources Role SARS coronavirus SARS-CoV-2 infection SARS-CoV-2 spike protein Signal Transduction Stimulus Surface Surveys Technology Testing Therapeutic Tissues Type 2 Angiotensin II Receptor Viral Viral Pathogenesis Virus Virus Diseases Virus Replication base cell type curative treatments cytokine design effective therapy human tissue improved innovation insight macromolecule novel coronavirus public health emergency receptor recruit response targeted treatment tissue injury transcription factor transmission process

项目摘要

PROJECT SUMMARY There is a pressing urgency to understand the regulatory mechanisms that control the expression of ACE2, the cellular receptor for the new coronavirus SARS-CoV-2, in human cells under physiological and pathological conditions. The binding between ACE2 and the SARS-CoV-2 spike protein, along with proteolytic cleavage of ACE2, facilitates entry of the coronavirus into target cells, viral replication, and transmission. As such, ACE2 has been proposed as a key factor in virus infectivity and disease pathology. Although ACE2 is hijacked by SARS-CoV-2 in the pathogenesis of COVID-19, its primary physiological role is to counteract tissue injury and inflammation as part of the renin-angiotensin system (RAS). The expression of ACE2 is restricted to specific tissue-resident cell types, developmentally regulated, and highly responsive to physiological (e.g. sex hormones) and pathological (e.g. inflammation or virus infection) signals. By surveying the epigenetic landscapes at the human ACE2 locus in the major ACE2-expressing cell types, we identified a set of gene- distal cis-regulatory elements (CREs) displaying tissue-specific activity, consistent with putative cell type- specific enhancer elements for ACE2. The molecular basis for the tissue- and developmental stage-specific expression of ACE2 is unknown, and the regulatory mechanisms controlling ACE2 expression in response to physiological and pathological signals remain unexplored, highlighting a critical gap in knowledge. Without an in-depth understanding of the molecular and cellular pathways that control ACE2 expression, the genetic or pharmacological modulation of ACE2 as an approach to therapy for COVID-19 will likely remain unreachable. The objective of this project is to close a critical gap in our understanding of the transcriptional mechanisms controlling ACE2 expression under normal and pathological conditions. The central hypothesis is that ACE2 expression is controlled by combinations of tissue-specific CREs to recruit cell type-specific and/or signal- dependent transcription factors. This hypothesis has been formulated on the basis of the tissue-specific expression profiles of ACE2 in human cells, the presence of multiple gene-distal CREs demarcated by active chromatin signatures in ACE2-expressing cells, and the differential effects on ACE2 expression upon physiological or pathological stimulations. Guided by these findings, this hypothesis will be tested by two specific aims: 1) Determine the functional roles of tissue-specific cis-regulatory elements in controlling ACE2 expression and its responses to stimuli; 2) Identify and characterize chromatin regulatory complexes responsible for ACE2 expression by CRISPR/dCas9-mediated affinity purification. Together, by focusing on the validated entry receptor for SARS-CoV-2, our studies will not only advance our mechanistic understanding of critical aspects of viral susceptibility and post-infection pathology, but also establish a much-needed resource of candidate cis- and trans-regulatory factors required for ACE2 expression in human cells, thus facilitating ongoing development of innovative strategies to leverage ACE2 as targeted therapies against COVID-19.

项目概要当务之急是了解控制 ACE2 表达的调控机制。新型冠状病毒SARS-CoV-2的细胞受体，在生理和病理状态下的人体细胞中状况。 ACE2 与 SARS-CoV-2 刺突蛋白之间的结合，以及蛋白水解切割 ACE2 促进冠状病毒进入靶细胞、病毒复制和传播。因此，ACE2 已被认为是病毒传染性和疾病病理学的关键因素。虽然ACE2被劫持了 SARS-CoV-2在COVID-19的发病机制中，其主要生理作用是抵抗组织损伤和炎症是肾素-血管紧张素系统（RAS）的一部分。 ACE2的表达仅限于特定的组织驻留细胞类型，受发育调节，对生理（例如性别）高度敏感激素）和病理（例如炎症或病毒感染）信号。通过调查表观遗传通过对主要表达 ACE2 的细胞类型中人类 ACE2 基因座的景观，我们鉴定了一组基因远端顺式调节元件（CRE）显示出组织特异性活性，与假定的细胞类型一致 ACE2 的特定增强子元件。组织和发育阶段特异性的分子基础 ACE2 的表达尚不清楚，并且控制 ACE2 表达的调控机制响应生理和病理信号仍未得到探索，凸显了知识方面的关键差距。没有深入了解控制 ACE2 表达的分子和细胞途径、遗传或 ACE2 的药理学调节作为治疗 COVID-19 的方法可能仍然无法实现。该项目的目标是弥合我们对转录机制理解的关键差距在正常和病理条件下控制 ACE2 的表达。中心假设是 ACE2 表达由组织特异性 CRE 的组合控制，以招募细胞类型特异性和/或信号- 依赖性转录因子。该假设是根据组织特异性提出的人类细胞中 ACE2 的表达谱，多个基因远端 CRE 的存在由活性物质划分表达 ACE2 的细胞中的染色质特征，以及对 ACE2 表达的差异影响生理或病理刺激。在这些发现的指导下，这个假设将由两个人来检验具体目标：1) 确定组织特异性顺式调控元件在控制 ACE2 中的功能作用表达及其对刺激的反应； 2) 识别和表征染色质调控复合物负责通过 CRISPR/dCas9 介导的亲和纯化表达 ACE2。共同努力，通过专注于经过验证的 SARS-CoV-2 进入受体，我们的研究不仅将增进我们对 SARS-CoV-2 机制的理解病毒易感性和感染后病理学的关键方面，同时也建立了急需的资源人类细胞中 ACE2 表达所需的候选顺式和反式调节因子，从而促进持续开发创新策略，利用 ACE2 作为针对 COVID-19 的靶向疗法。