mTOR and VEGFR2 pathways in HHT pathogenesis

HHT 发病机制中的 mTOR 和 VEGFR2 通路

基本信息

批准号：
10229604
负责人：
PHILIPPE MARAMBAUD
金额：
$ 41.88万
依托单位：
FEINSTEIN INSTITUTE FOR MEDICAL RESEARCH
依托单位国家：
美国
项目类别：
财政年份：
2020
资助国家：
美国
起止时间：
2020-08-05 至 2024-06-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10229604
关键词：
ANGPT1 gene Anemia Angiogenic Factor Angiopoietin-2 Arteriovenous malformation Blood Blood Coagulation Disorders Blood Vessels Cell model Data Defect Development Disease Dominant Genetic Conditions Drug Targeting ENG gene Endothelial Cells Endothelium FRAP1 gene Gene Abnormality Gene Deletion Gene Expression Profile Genes Genetic Genetic Diseases Genetic Transcription Goals Hemorrhage Hereditary hemorrhagic telangiectasia In Vitro Intervention Investigation KDR gene Knock-in Mouse Knockout Mice Lead Lesion Life Liver Lung Mediating Modeling Mucous Membrane Mus Mutation Organ Pathogenesis Pathologic Pathology Pathway interactions Patients Pharmacology Phosphoric Monoester Hydrolases Play Process Property Proteins Receptor Protein-Tyrosine Kinases Receptor Signaling Reporting Repression Retina Retinal Diseases Role Series Signal Transduction Sirolimus Solid TIE-2 Receptor Testing Therapeutic Tissues Tyrosine Kinase Inhibitor angiogenesis base clinical investigation derepression design experimental study in vivo loss of function mTOR Inhibitor mTOR inhibition mouse model programs public health relevance receptor synergism transcriptome transcriptome sequencing vascular endothelial protein tyrosine phosphatase

项目摘要

PROJECT SUMMARY/ABSTRACT (DESCRIPTION) Hereditary hemorrhagic telangiectasia (HHT) is an autosomal dominant genetic disorder characterized by the development of systemic and potentially life-threatening vascular anomalies called arteriovenous malformations (AVMs). HHT mutations are mostly found in the ALK1 and ENG genes and lead to a loss-of-function of BMP9/10- ALK1-ENG signaling in endothelial cells (ECs). Recent evidence suggests that HHT pathogenesis and AVM development require the aberrant overactivation of the endothelial mTOR and VEGFR2 pathways. The overall goal of this program is to characterize the precise mechanisms of mTOR and VEGFR2 overactivations upon ALK1-ENG loss-of-function, and determine whether targeting of these mechanisms has disease-modifying properties and therapeutic potential in cell and mouse models of HHT. Using whole-transcriptome interrogation, our preliminary investigation has shown that combined pharmacological inhibition of mTOR and VEGFR2 demonstrated a remarkable synergy and efficacy in correcting a pathological gene expression signature in the BMP9/10-immunoblocked (BMP9/10ib) mouse model of HHT. Strikingly, dual mTOR-VEGFR2 inhibition blocked vascular pathology and AVMs in the retina, liver, lungs, and mucosa to avert bleeding and anemia in BMP9/10ib mice. Mechanistically, our preliminary data revealed that, downstream of ALK1-ENG inhibition, changes in angiopoietin-2 (ANG2)/Tie2 receptor signaling were important triggers for mTOR-VEGFR2 activation and AVM development in HHT mice. Therefore, our data support the working model that HHT pathogenesis is caused by defective ANG2-mTOR-VEGFR2 pathways, and that interventions targeting these mechanistic defects might provide therapeutic benefit in HHT. Based on these results, we propose in Aim 1 to assess whether endothelial mTOR and VEGFR2 are independently activated and whether they are both required for AVM development in HHT mice. To this end, pharmacological and gene deletion approaches independently targeting mTOR and VEGFR2 will be employed in two HHT mouse models: the BMP9/10ib mice and a newly generated knockin (KI) mouse expressing a HHT-causing ALK1 mutation. In Aim 2, we will delineate the precise mechanism of mTOR and VEGFR2 overactivation by ANG2/Tie2 signaling, both in vivo in HHT mice and in vitro in primary ECs, including in HHT patient blood outgrowth ECs. Lastly in Aim 3, we will determine whether Tie2 derepression blocks vascular pathology in HHT mice.

项目摘要/摘要（描述）遗传性出血性毛细血管扩张症（HHT）是一种常染色体显性遗传病，其特征为发生全身性的、可能危及生命的血管异常，称为动静脉畸形（AVM）。 HHT 突变主要存在于 ALK1 和 ENG 基因中，并导致 BMP9/10- 功能丧失内皮细胞 (EC) 中的 ALK1-ENG 信号传导。最近的证据表明 HHT 发病机制和 AVM 发育需要内皮 mTOR 和 VEGFR2 通路的异常过度激活。整体该计划的目标是描述 mTOR 和 VEGFR2 过度激活的精确机制 ALK1-ENG 功能丧失，并确定这些机制的靶向是否具有疾病缓解作用 HHT 细胞和小鼠模型的特性和治疗潜力。使用全转录组询问，我们的初步研究表明，mTOR 和 VEGFR2 的联合药理学抑制在纠正病理性基因表达特征方面表现出显着的协同作用和功效 HHT 的 BMP9/10 免疫阻断 (BMP9/10ib) 小鼠模型。引人注目的是，mTOR-VEGFR2 双重抑制被阻断视网膜、肝脏、肺和粘膜的血管病理学和 AVM，以避免 BMP9/10ib 中的出血和贫血老鼠。从机制上讲，我们的初步数据表明，在 ALK1-ENG 抑制的下游，血管生成素-2 (ANG2)/Tie2 受体信号传导是 mTOR-VEGFR2 激活和 AVM 的重要触发因素 HHT 小鼠的发育。因此，我们的数据支持 HHT 发病机制是由以下因素引起的工作模型：有缺陷的 ANG2-mTOR-VEGFR2 通路，针对这些机制缺陷的干预措施可能会在 HHT 中提供治疗益处。基于这些结果，我们在目标 1 中建议评估内皮细胞是否 mTOR 和 VEGFR2 是否独立激活以及它们是否都是 AVM 发展所必需的 HHT 小鼠。为此，药理学和基因删除方法分别针对 mTOR 和 VEGFR2 将用于两种 HHT 小鼠模型：BMP9/10ib 小鼠和新生成的敲入 (KI) 表达引起 HHT 的 ALK1 突变的小鼠。在目标2中，我们将描述mTOR的精确机制以及 ANG2/Tie2 信号传导导致的 VEGFR2 过度激活，无论是在 HHT 小鼠体内还是在体外原代 EC 中，包括 HHT 患者血液生长的 EC。最后在目标 3 中，我们将确定 Tie2 是否去抑制阻断 HHT 小鼠的血管病理学。