The role of IFT80 in bone formation

IFT80 在骨形成中的作用

基本信息

批准号：
8432452
负责人：
SHUYING YANG
金额：
$ 7.53万
依托单位：
STATE UNIVERSITY OF NEW YORK AT BUFFALO
依托单位国家：
美国
项目类别：
财政年份：
2012
资助国家：
美国
起止时间：
2012-03-01 至 2015-02-28
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8432452
关键词：
Ablation Alleles Animal Model Bardet-Biedl Syndrome Blindness Bone Development Bone Diseases Carrier Proteins Cartilage Cell Differentiation process Cell Proliferation Cephalic Chest Cilia Code Complex Craniofacial Abnormalities Data Defect Diabetes Mellitus Diagnosis Disease Ellis-Van Creveld Syndrome Epiphysial cartilage Erinaceidae Flagella Functional disorder Gene Deletion Gene Expression Gene Expression Regulation Genes Goals Growth Human In Vitro Individual Jeune syndrome KRP protein Kidney Kidney Diseases Knock-out Lead Limb structure Maintenance Malignant Neoplasms Mediating Microtubules Modeling Motor Mus Mutant Strains Mice Mutate Mutation Nail plate Nature Organism Osteoblasts Osteocalcin Osteogenesis Osteopenia Pathway interactions Patients Phenotype Play Polydactyly Prevention strategy Primary Ciliary Dyskinesias Proteins Reporting Retina Role Sensory Short Rib-Polydactyly Syndrome Signal Pathway Signal Transduction Skeleton Solid Syndrome Testing Tooth structure Work animal behavior development base bone cell motility constriction developmental disease human disease in vivo insight interest intramembranous bone formation long bone novel osteoblast differentiation rib bone structure skeletal abnormality smoothened signaling pathway substantia spongiosa

项目摘要

DESCRIPTION (provided by applicant): Intraflagellar transport (IFT) proteins are microtubule based transport machinery, which are essential for the assembly and maintenance of all cilia and flagella. Recent findings have not only revealed the various roles of cilia and flagella in motility, sensory reception, and signaling, but also demonstrated the function of IFT in the control of gene regulation and expression, cell proliferation and differentiation, and animal development and behavior. The mutation of IFT proteins causes the loss or severe reduction of cilia and flagella in various organisms, which can lead to numerous human diseases characterized by various combinations of pathological changes of kidney, retina, and skeleton. Conditional ablation of IFT88 disrupts hedgehog signaling, with polydactyly and defects of endochondral bone formation. Disruption of Kif3a, a subunit of kinesin II, showed limb and cranial skeletal abnormalities. Recently, a novel protein mutated in chondroectodermal dysplasia Ellis-van Creveld syndrome (EVC) was found to be localized to the base of the cilia, and disruption of this gene in mice results in a variety of skeletal and craniofacial abnormalities as well as alterations in the teeth and nails. Mice with targeted deletion of IFT/cilia have a wide variety of bone phenotypes that provide interesting insights into the function of individual IFT protein in bone formation. Most recently, Beales et al group found that the partial loss of IFT80 in human, a novel component of the IFT complex B, causes human diseases such as Jeune asphyxiating thoracic dystrophy (JATD) and short rib polydactyly (SRP) type III. Both diseases have severe bone abnormalities including shortening of the long bones and constriction of the thoracic cage. However, it is unclear how IFT80 mutation leads to skeletal abnormalities. Our recent studies have shown that IFT80 is highly expressed during osteoblast differentiation. Silencing IFT80 not only impairs cilia formation, but also significantly inhibits osteoblast differentiation through down-regulating the expression of osteoblast marker genes- Runx2 and osteocalcin, and hedgehog signaling (Hh) related genes -shh, Ihh and Gli2. These are important results; nonetheless, there is still no in vivo evidence for a general requirement for IFT80 signaling in osteoblast differentiation and bone formation. Most recently, we have generated IFT80 conditional knockout model in osteoblast specific lineage and found that IFT80 mutant mice showed apparent growth retardation with severe bone abnormalities. Based on these results, we hypothesize that IFT80 plays an essential role in vertebrate bone formation and normal bone function through regulating osteoblast gene expression, differentiation and Hh/Gli pathway. In this proposal, we will test the hypothesis by generating an IFT80 conditional knockout allele to study the role of IFT80 in bone formation and investigating the effect of deletion of this gene on osteoblast gene expression, differentiation and proliferation. The long term objective of this work is to understand the functionmechanism and interactions of IFT/cilia proteins in bone development and bone diseases.

描述（由申请人提供）：鞭毛内运输（IFT）蛋白是基于微管的运输机械，对于所有纤毛和鞭毛的组装和维护至关重要。最近的研究结果不仅揭示了纤毛和鞭毛在运动、感觉接收和信号传导中的各种作用，而且还证明了 IFT 在控制基因调控和表达、细胞增殖和分化以及动物发育和行为中的功能。 IFT蛋白的突变导致多种生物体中纤毛和鞭毛的缺失或严重减少，从而导致多种以肾脏、视网膜和骨骼病理变化组合为特征的人类疾病。 IFT88 的条件性消融会破坏刺猬信号传导，导致多指畸形和软骨内骨形成缺陷。 Kif3a（驱动蛋白 II 的一个亚基）的破坏会导致四肢和颅骨骨骼异常。最近，发现软骨外胚层发育不良埃利斯-范克雷维尔德综合征（EVC）中的一种新的突变蛋白位于纤毛基部，小鼠体内该基因的破坏会导致多种骨骼和颅面畸形以及牙齿和指甲的变化。靶向删除 IFT/纤毛的小鼠具有广泛的多种骨表型，为了解单个 IFT 蛋白在骨形成中的功能提供了有趣的见解。最近，Beales等人的研究小组发现，人类中IFT80（IFT复合物B的一种新成分）的部分缺失会导致人类疾病，例如青年窒息性胸廓营养不良（JATD）和III型短肋多指畸形（SRP）。这两种疾病都有严重的骨骼异常，包括长骨缩短和胸廓收缩。然而，尚不清楚IFT80突变如何导致骨骼异常。我们最近的研究表明，IFT80 在成骨细胞分化过程中高表达。沉默IFT80不仅损害纤毛形成，而且还通过下调成骨细胞标记基因Runx2和骨钙素以及刺猬信号（Hh）相关基因shh、Ihh和Gli2的表达，显着抑制成骨细胞分化。这些都是重要的结果；尽管如此，仍然没有体内证据表明成骨细胞分化和骨形成中普遍需要IFT80信号。最近，我们在成骨细胞特异性谱系中建立了IFT80条件敲除模型，发现IFT80突变小鼠表现出明显的生长迟缓和严重的骨骼异常。基于这些结果，我们假设IFT80通过调节成骨细胞基因表达、分化和Hh/Gli途径在脊椎动物骨形成和正常骨功能中发挥重要作用。在本提案中，我们将通过生成IFT80条件敲除等位基因来检验该假设，以研究IFT80在骨形成中的作用，并研究该基因的缺失对成骨细胞基因表达、分化和增殖的影响。这项工作的长期目标是了解 IFT/纤毛蛋白在骨发育和骨疾病中的功能机制和相互作用。