Impact of microfibril turnover on vascular development and disease

微原纤维周转对血管发育和疾病的影响

基本信息

批准号：
10741427
负责人：
Timothy Joseph Mead
金额：
$ 40.25万
依托单位：
CASE WESTERN RESERVE 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：
2021-12-01 至 2026-11-30
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10741427
关键词：
ADAMTS Address Adult Affect Alleles Aneurysm Aorta Aortic Aneurysm Arteries Binding Binding Sites Biochemical Biological Biological Assay Birth Blood Vessels Cell Culture Techniques Cells Cessation of life Chronic Clinical Connective Tissue Diseases Cytoskeleton Data Defect Development Disease Dissection Elastic Fiber Embryo Embryonic Development Extracellular Matrix FBN1 Family member Fibrillin Microfibrils Foundations Future Genes Goals Growth Growth Factor Health Heart Abnormalities Hereditary Disease Homeostasis Human In Vitro Incidence Inherited Investigation Knock-out Link Longevity LoxP-flanked allele Maps Marfan Syndrome Mechanics Mediating Metalloproteases Microfibrils Minor Modeling Molecular Morbidity - disease rate Mus Mutation Operative Surgical Procedures Outcome Patients Peptide Hydrolases Peptides Post-Translational Protein Processing Proteolysis Recombinants Research Risk Role Rupture Smooth Muscle Myocytes Structure Surface Plasmon Resonance Testing Therapeutic Thoracic Aortic Aneurysm Tissues Vascular Smooth Muscle Work autosome cell growth regulation conditional mutant experimental study fibrillin fibrillin-2 insight intermolecular interaction mortality mouse model mutant novel postnatal postnatal period prevent prospective screening skeletal targeted treatment

项目摘要

SUMMARY Dominant FBN1 mutations cause Marfan syndrome, an inherited human connective tissue disorder affecting fibrillin-1 microfibrils and leading to thoracic aortic aneurysms with risk of aortic dissection and rupture. Fibrillin- 1 is a product of vascular smooth muscle cells (VSMC), which provides an important link in the mechanical continuum from the SMC contractile cytoskeleton to the extracellular matrix, in addition to providing a template for elastic fiber assembly. Reduced tissue fibrillin-1 content as a result of FBN1 haploinsufficiency is thought to be the mechanism underlying a significant proportion (over 1/3) of Marfan syndrome mutations. In recent work we found that ADAMTS6, a metalloprotease secreted by VSMC, cleaves both fibrillin-1 and fibrillin-2. The latter is produced primarily during the embryonic period and is thought to have a minor role in the aorta after birth. Analysis of a mouse Adamts6 null mutant, which does not survive past birth, shows an accumulation of both fibrillin-1 and fibrillin-2, with major skeletal and cardiac defects we have genetically attributed to fibrillin-2 accumulation. Thus, ADAMTS6 appears to be a major protease regulating fibrillin microfibril turnover. This provides a compelling rationale for targeting ADAMTS6 in Marfan syndrome in a novel disease- modifying approach. Based on these findings, the overarching hypothesis of this proposal is that ADAMTS6 inactivation in vascular smooth muscle cells postnatally will protect aortic fibrillin-1 microfibrils from proteolytic turnover, thus increasing microfibril abundance and mitigating aortic aneurysm growth and dissection in Marfan syndrome. In Aim 1, we will use a new Adamts6 conditional mutant to test this hypothesis through conditional deletion of Adamts6 in VSMCs in a well-characterized mouse model of severe Marfan syndrome that reliably progresses to dissection and rupture. In Aim 2, we will define the intermolecular interaction of fibrillin-1 and ADAMTS6 to identify the major molecular determinants of proteolysis. In vitro microfibril assembly will be used to test the impact of blocking ADAMTS6-fibrillin interactions. These experiments will inform future approaches for protecting microfibrils from ADAMTS6-mediated turnover. Impact: A disease-modifying approach for Marfan syndrome does not exists, and non-surgical options have not been wholly effective in preventing dissection. These aims leverage our initial discovery that ADAMTS6 cleaves fibrillin-1 for continued investigations intended to drive development of an ADAMTS6 blockade-based disease- modifying approach for Marfan syndrome. Specifically, the disease mechanism in many patients is reduction of fibrillin-1 microfibrils and we aim to enhance microfibril abundance by protecting them from breakdown. Together the aims provide a proof of principle for a possible disease-modifying therapy (Aim 1) and the basis for interfering with ADAMTS6 cleavage of fibrillin-1 (Aim 2). The work proposed herein also addresses fundamental questions of how fibrillin-1 is turned over in the vascular wall.

概括 FBN1 显性突变导致马凡综合征，这是一种遗传性人类结缔组织疾病，影响 fibrillin-1 微纤维并导致胸主动脉瘤，具有主动脉夹层和破裂的风险。原纤维蛋白- 1是血管平滑肌细胞（VSMC）的产物，它在机械运动中提供了重要的环节除了提供模板之外，从 SMC 收缩细胞骨架到细胞外基质的连续体用于弹性纤维组装。 FBN1 单倍体不足导致组织原纤维蛋白 1 含量减少，被认为是大部分（超过 1/3）马凡综合征突变的潜在机制。在最近的工作中，我们发现 ADAMTS6（一种由 VSMC 分泌的金属蛋白酶）可以裂解 fibrillin-1 和 fibrillin-1。原纤维蛋白-2。后者主要在胚胎期产生，被认为在发育过程中发挥次要作用。出生后的主动脉。对出生后无法存活的小鼠 Adamts6 无效突变体的分析显示，原纤维蛋白 1 和原纤维蛋白 2 的积累，以及我们在遗传上发现的主要骨骼和心脏缺陷归因于 fibrillin-2 的积累。因此，ADAMTS6 似乎是调节原纤维蛋白微原纤维的主要蛋白酶周转。这为在一种新疾病中针对马凡综合征中的 ADAMTS6 提供了令人信服的理由—— 修改方法。基于这些发现，该提案的总体假设是血管中 ADAMTS6 失活出生后的平滑肌细胞将保护主动脉原纤维蛋白-1 微纤维免受蛋白水解更新，从而增加微纤维丰度和减轻马凡综合征中的主动脉瘤生长和夹层。在目标 1 中，我们将使用新的 Adamts6 条件突变体通过条件删除 Adamts6 来检验这一假设严重马凡综合征小鼠模型中的 VSMC 可靠地进展为解剖和破裂。在目标 2 中，我们将定义 fibrillin-1 和 ADAMTS6 的分子间相互作用，以确定蛋白水解的主要分子决定因素。体外微纤维组装将用于测试的影响阻断 ADAMTS6-原纤维蛋白相互作用。这些实验将为未来的保护方法提供信息 ADAMTS6 介导的周转产生的微纤维。影响：马凡综合征的疾病缓解方法尚不存在，非手术选择也尚未出现完全有效地防止解剖。这些目标利用了我们最初发现 ADAMTS6 裂解 fibrillin-1 用于继续研究，旨在推动基于 ADAMTS6 阻断的疾病的开发马凡综合征的改良方法。具体来说，许多患者的疾病机制是减少 fibrillin-1 微原纤维，我们的目标是通过保护微原纤维免遭分解来提高微原纤维的丰度。一起这些目标为可能的疾病缓解疗法（目标 1）提供了原理证明以及干扰的基础 ADAMTS6 裂解 fibrillin-1（目标 2）。本文提出的工作还解决了基本问题 fibrillin-1 如何在血管壁中翻转。