Regulation of Skeletal Growth by Soft Tissue Extracellular Matrix

软组织细胞外基质对骨骼生长的调节

基本信息

批准号：
9529512
负责人：
Dirk Hubmacher
金额：
$ 37.29万
依托单位：
ICAHN SCHOOL OF MEDICINE AT MOUNT SINAI
依托单位国家：
美国
项目类别：
财政年份：
2018
资助国家：
美国
起止时间：
2018-03-01 至 2022-06-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/9529512
关键词：
ADAMTS Address Affect Bees Binding Binding Proteins Biochemical Biological Biological Assay Biomechanics Birth Bone Growth Cartilage Cell Culture Techniques Cells Chondrocytes Chondrogenesis Connective Tissue Data Digit structure Disease Distal Dysplasia Epiphysial cartilage Etiology Extracellular Matrix Extracellular Matrix Proteins FBN1 Fibrillin Microfibrils Fibroblasts Functional disorder Gene Dosage Gene Expression Gene Expression Profiling Gene Mutation Genes Genetic Genetic Diseases Genetic Transcription Glycoproteins Growth Histologic Human Human Genetics Impairment Individual Joint Laxity Joints Knockout Mice LTBP2 gene Lead Length Ligaments Limb Bud Limb structure MADH4 gene Maps Marfan Syndrome Mechanics Mediating Mendelian disorder Mesenchyme Messenger RNA Microfibrils Modeling Molecular Mus Musculoskeletal Mutation Pathway interactions Peptide Hydrolases Phenotype Physiological Property Protein Isoforms Proteins Recombinants Regulation Reporting Roentgen Rays Role Signal Transduction Site Skeletal Muscle Structure Syndrome System Tendon structure Testing Tissues Transcriptional Regulation Transforming Growth Factors Translating Western Blotting X-Ray Computed Tomography achilles tendon bone fibrillin fibrillin-2 geleophysic dysplasia insight joint stiffness microCT mouse model novel novel therapeutics postnatal prenatal protein protein interaction regenerative skeletal soft tissue

项目摘要

ABSTRACT While it is undisputed that extracellular matrix and soft tissues influence skeletal growth, few specific pathways explaining this effect have been uncovered. In Marfan syndrome, which affects 1-2 in 5000 individuals, skeletal overgrowth, long digits, poorly developed musculature and lax joints result from fibrillin-1 (FBN1) mutations. Strikingly, specific mutations in FBN1 can also cause the “opposite” of Marfan syndrome, i.e. short stature, disproportionally short digits (brachydactyly), stiff joints, and a “pseudomuscular” build, which are the hallmarks of acromelic dysplasias, comprising a group of Mendelian disorders. Identical acromelic dysplasias can also be caused by genes encoding ADAMTS proteases, ADAMTS-like (ADAMTSL) proteins, latent transforming growth factor- (TGF) binding protein-3 (LTBP3), and SMAD4. The overlapping phenotypes of different gene mutations underlying acromelic dysplasias strongly support my hypothesis that a fibrillin-ADAMTS-TGF axis constitutes a novel extracellular matrix (ECM) network regulating postnatal limb growth. Mutations in ADAMTSL2 or FBN1 lead to geleophysic dysplasia (GD), a severe, frequently lethal human acromelic dysplasia. ADAMTSL2 is a secreted glycoprotein that binds to FBN1 and FBN2, and is implicated in TGF signaling. Intriguingly, ADAMTSL2 mRNA is not expressed in growth plate cartilage or bone, but has its strongest expression in tendon. My studies show that FBN2 microfibrils are increased at sites of Adamtsl2 expression in a mouse knockout model of GD, suggesting a role for ADAMTSL2 in switching from prenatal FBN2-dominated microfibrils to postnatal FBN1-dominated microfibrils. Furthermore, skeletal growth is impaired upon limb-specific ADAMTSL2 deletion (Prx1-Cre) or tendon and ligament specific deletion (Scx- Cre). I observed disproportionate distal limb shortening (i.e. acromelic dysplasia) and a reduction in Achilles tendon length in both conditional deletions. A model for skeletal growth in geleophysic dysplasia provides an opportunity to determine how tissue non-autonomous regulation of skeletal growth occurs via mechanical or regulatory input from tendon ECM. In aim 1, I will test the hypothesis by analyzing postnatal limb growth and ECM alterations in the microfibril system after Adamtsl2 deletion in tendons with Scx-Cre. In aim 2, I will investigate how ADAMTSL2 interacts with FBN1 and FBN2 and how ADAMTSL2 executes its role in the isoform switch from FBN2 to FBN1. I will analyze the genetic interaction of Adamtsl2 with Fbn1 and Fbn2 in mice and I will use protein-protein interaction studies and cell culture assays to gain mechanistic insights in the function of ADAMTSL2 in regulating the fibrillin isoform switch. Impact: The anticipated results will provide novel insights into the pathophysiology of acromelic dysplasias and other fibrillinopathies. These insights could be translated for targeting tendon ECM in regenerative strategies. The proposal addresses fundamental questions of how functional properties of soft tissues are determined by ECM subsequently might regulate postnatal limb growth.

抽象的虽然细胞外基质和软组织影响骨骼生长是毫无争议的，但很少有具体的途径在影响 5000 人中有 1-2 人的马凡氏综合症中，我们已经发现了这种效应的解释。原纤维蛋白-1 (FBN1) 突变导致过度生长、手指过长、肌肉组织发育不良和关节松弛。引人注目的是，FBN1 的特定突变也可能导致马凡综合征的“相反”情况，即身材矮小、不成比例的短指（短指）、僵硬的关节和“假肌肉”体型，这些都是其标志也可以是包括一组相同的肢端发育不良的肢端发育不良。由编码 ADAMTS 蛋白酶、ADAMTS 样 (ADAMTSL) 蛋白、潜在转化的基因引起生长因子- (TGF) 结合蛋白-3 (LTBP3) 和 SMAD4 不同基因的重叠表型。潜在突变肢端发育不良强烈支持我的假设，即原纤维蛋白-ADAMTS-TGF轴构成了调节产后肢体生长的新型细胞外基质（ECM）网络。 ADAMTSL2 或 FBN1 的突变会导致凝胶物理发育不良 (GD)，这是一种严重且经常致命的人类疾病 ADAMTSL2 是一种与 FBN1 和 FBN2 结合的分泌型糖蛋白，与 FBN1 和 FBN2 相关。有趣的是，ADAMTSL2 mRNA 不在生长板软骨或骨中表达，但有其自身的表达。我的研究表明 FBN2 微纤维在 Adamtsl2 部位增加。在 GD 小鼠敲除模型中表达，表明 ADAMTSL2 在从产前转换中发挥作用 FBN2 主导的微原纤维到出生后 FBN1 主导的微原纤维此外，骨骼生长也是如此。肢体特异性 ADAMTSL2 缺失 (Prx1-Cre) 或肌腱和韧带特异性缺失 (Scx- Cre）我观察到远端肢体不成比例的缩短（即肢端发育不良）和跟腱减少。两种条件性缺失中的肌腱长度提供了骨骼生长发育不良的模型。有机会确定骨骼生长的组织非自主调节如何通过机械或来自肌腱 ECM 的调节输入在目标 1 中，我将通过分析出生后肢体的生长和发育来检验这一假设。使用 Scx-Cre 删除肌腱 Adamtsl2 后微纤维系统中的 ECM 变化在目标 2 中，我将。研究 ADAMTSL2 如何与 FBN1 和 FBN2 相互作用以及 ADAMTSL2 如何在我将分析 Adamtsl2 与 Fbn1 和 Fbn2 的遗传相互作用。我和小鼠将利用蛋白质-蛋白质相互作用研究和细胞培养测定来获得关于 ADAMTSL2 在调节原纤维蛋白亚型开关中的功能。影响：预期的结果将为肢端发育不良的病理生理学提供新的见解这些见解可以转化为针对肌腱 ECM 的再生策略。该提案解决了软组织功能特性如何由以下因素决定的基本问题： ECM 随后可能调节产后肢体生长。