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

• 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
• 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

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.

项目摘要 有一个紧迫的紧迫性，以了解控制ACE2表达的调节机制，即 在生理和病理学下，人类细胞中新的冠状病毒SARS-COV-2的细胞受体 状况。 ACE2和SARS-COV-2尖峰蛋白之间的结合，以及蛋白水解的裂解 ACE2，促进冠状病毒进入靶细胞，病毒复制和传播。因此，ACE2 已提出是病毒感染和疾病病理学的关键因素。虽然ACE2被劫持 SARS-COV-2在COVID-19的发病机理中，其主要的生理作用是抵消组织损伤和 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 组织居住的细胞类型，受发展调节，对生理的反应很高（例如性别 激素）和病理（例如炎症或病毒感染）信号。通过调查表观遗传学 主要表达ACE2细胞类型的人ACE2基因座的景观，我们确定了一组基因 远端顺式调节元件（CRE）显示组织特异性活性，与推定的细胞类型一致 ACE2的特定增强子元素。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表达的调节机制响应于 生理和病理信号仍未开发，突出了知识的危险差距。没有一个 深入了解控制ACE2表达，遗传或 ACE2作为COVID-19的治疗方法的药理调节可能仍然无法达到。 该项目的目的是弥合我们对转录机制的理解的关键差距 在正常和病理条件下控制ACE2表达。中心假设是Ace2 表达受组织特异性CR的组合来控制，以募集细胞类型特异性和/或信号 - 依赖转录因子。该假设已根据组织特异性提出 ACE2在人类细胞中的表达曲线，由活性划分的多个基因偏见的存在 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，该假设将由两个检验 具体目的：1）确定组织特异性顺式调节元件在控制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节复合物 由CRISPR/DCAS9介导的亲和力纯化负责ACE2表达。一起，专注于 经过验证的SARS-COV-2进入受体，我们的研究不仅会提高我们对 病毒易感性和感染后病理学的关键方面，但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 持续发展创新策略，以利用ACE2作为针对Covid-19的有针对性疗法。