mTOR and VEGFR2 pathways in HHT pathogenesis

HHT 发病机制中的 mTOR 和 VEGFR2 通路

• 批准号: 10652406
• 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
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-08-05 至 2025-06-30
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10652406
• 关键词: ANGPT1 gene; Anemia; Angiogenic Factor; Angiopoietin-2; Arteriovenous malformation; Blood; Blood Coagulation Disorders; Blood Vessels; Cell model; Combined Modality Therapy; 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; PIK3CG gene; Pathogenesis; Pathologic; Pathology; Pathway interactions; Patients; 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; autosome; clinical investigation; derepression; design; experimental study; in vivo; loss of function; mTOR Inhibitor; mTOR inhibition; mouse model; nintedanib; pharmacologic; programs; public health relevance; receptor; synergism; transcriptome; transcriptome sequencing; vascular endothelial protein tyrosine phosphatase; ANGPT1 gene; Anemia; Angiogenic Factor; Angiopoietin-2; Arteriovenous malformation; Blood; Blood Coagulation Disorders; Blood Vessels; Cell model; Combined Modality Therapy; 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; PIK3CG gene; Pathogenesis; Pathologic; Pathology; Pathway interactions; Patients; 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; autosome; clinical investigation; derepression; design; experimental study; in vivo; loss of function; mTOR Inhibitor; mTOR inhibition; mouse model; nintedanib; pharmacologic; programs; public health relevance; receptor; synergism; transcriptome; transcriptome sequencing; vascular endothelial protein tyrosine phosphatase

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（HHT）是一种常染色体显性遗传疾病，其特征是 形成系统性和潜在威胁生命的血管异常，称为动脉畸形 （AVMS）。 HHT突变主要在ALK1和ENG基因中发现，并导致BMP9/10-的功能丧失。 内皮细胞（EC）中的ALK1-ENG信号传导。最近的证据表明HHT发病机理和AVM 开发需要内皮MTOR和VEGFR2途径的异常活化。总体 该程序的目标是表征MTOR和VEGFR2过度激活的精确机制 ALK1-ENG的功能丧失，并确定这些机制的靶向是否具有疾病修改 HHT细胞和小鼠模型中的性质和治疗潜力。使用全转录组询问， 我们的初步研究表明，MTOR和VEGFR2的药理学抑制 在纠正病理基因表达特征中表现出了显着的协同作用和功效 HHT的BMP9/10-ImmunoBlocked（BMP9/10IB）鼠标模型。引人注目的是，双MTOR-VEGFR2抑制作用被阻止 视网膜，肝脏，肺和粘膜中的血管病理和AVM，以避免出血和贫血在BMP9/10IB中 老鼠。从机械上讲，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的重要触发器 HHT小鼠的发育。因此，我们的数据支持HHT发病机理的工作模型 Ang2-Mtor-VEGFR2途径有缺陷，针对这些机械缺陷的干预措施可能 在HHT中提供治疗益处。基于这些结果，我们建议在目标1中评估内皮是否是否 MTOR和VEGFR2是独立激活的，是否都需要AVM开发 HHT小鼠。为此，药理学和基因缺失的方法是独立针对MTOR和 VEGFR2将用于两种HHT鼠标模型：BMP9/10IB小鼠和新产生的敲蛋白（KI） 表达引起HHT的ALK1突变的小鼠。在AIM 2中，我们将描述MTOR的确切机制 ang2/tie2信号传导过度活化的VEGFR2，均在HHT小鼠中的体内和一级EC中的体外， 包括HHT患者血液生长EC。最后，在AIM 3中，我们将确定tie2剥夺是否 阻断HHT小鼠的血管病理。