Roles of the Fat pathway in cartilage patterning and polarity

脂肪途径在软骨模式和极性中的作用

• 批准号: 8509658
• 负责人: Thomas F Schilling
• 金额: $ 35.38万
• 依托单位: UNIVERSITY OF CALIFORNIA-IRVINE
• 依托单位国家: 美国
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-04-01 至 2017-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8509658
• 关键词: Address; Animals; Atrophic; Binding; Biomedical Engineering; Birds; Bone Morphogenetic Proteins; Branchial arch structure; Cadherins; Candidate Disease Gene; Cartilage; Cartilage injury; Cell Communication; Cell Polarity; Cell Transplantation; Cell physiology; Cells; Chondrocytes; Chondrogenesis; Cilia; Clinical; Collagen; Complement; Congenital Abnormality; Couples; Development; Diagnosis; Diagnostic; Dorsal; Elements; Embryo; Embryonic Development; Endothelin-1; Epithelium; Event; Fatty acid glycerol esters; Genetic; Goals; Growth; Growth Factor; Human; Image; Joints; Laboratories; Lead; Life; Ligands; Link; Mandible; Mesenchymal; Modeling; Molecular; Morphogenesis; Movement; Mus; Mutation; Neurodegenerative Disorders; Organ; Pathway interactions; Pattern; Phenocopy; Phenotype; Physical condensation; Population; Process; Protein Deficiency; Regulation; Relative (related person); Role; Shapes; Signal Pathway; Signal Transduction; Skeletal system; Skeleton; Source; Stem cells; Temporomandibular Joint; Testing; Time; Vertebrates; Zebrafish; cartilage development; cell type; craniofacial; fly; genetic manipulation; improved; insight; joint injury; loss of function; malformation; mutant; novel marker; overexpression; prevent; progenitor; research study; response; skeletal; skeletogenesis; transcription factor

DESCRIPTION (provided by applicant): A functional skeletal system depends upon the coordinated development of cartilages and joints during embryogenesis. However, little is known about the cellular and molecular mechanisms that control cartilage size, shape or connectivity. Progress unraveling the signals that direct mesenchymal cells to condense and align into prechondrogenic stacks is of particular importance in elucidation of the early events that shape the organization and growth of the skeleton. Understanding these processes will allow better diagnostic approaches and treatments for skeletal malformations and birth defects. Moreover, molecules that control cartilage morphogenesis and differentiation may be of considerable clinical importance both for improvements in the treatment of cartilage and joint injuries and in bioengineering efforts to induce cartilage formation from stem cells. Our recent finding that Rere, a close relative of the transcription factor Atrophin which regulates Dachsous (Dchs)-Fat signaling in flies, is required for craniofacial development in zebrafish has implicated the Fat pathway in planar cell polarity (PCP) during skeletogenesis. Dramatic results from our laboratory now demonstrate an even more profound role for a Fat3 in cartilage differentiation, consistent with PCP. Embryos deficient in Rere or Fat3 develop cartilages in which stacking and differentiation are uncoupled in the pharyngeal arches and this leads to joint fusion. Moreover, Rere and Fat3 are critical for coordinating responses of skeletal progenitors to Bmp and Fgf signaling during craniofacial development. We propose to explore the roles of the Fat pathway and PCP in cartilage and joint formation in three sets of experiments. The first aim will address the hypothesis that the Fat pathway couples cartilage stacking and differentiation. Cartilage and joint phenotypes will be evaluated in Rere and Fat3 mutants using live imaging. We will identify the Dchs ligand(s) for Fat in cartilage and create ectopic sources to study signal propagation and modulation. We will also compare the activities of the Fat pathway and Wnt/PCP and their interdependence in cartilage development. The second aim will address the hypothesis that the Fat pathway coordinates polarized responses to Bmps and other growth factors, thereby linking early patterning events with later organ formation. For this we have new markers of cytoskeletal polarity and cilia that reveal unexpected boundaries of polarity in skeletal progenitors. Finally, the third aim will focus on joint formation and test the hypothesis that the Fat pathway prevents cartilage stacking and differentiation in the joint interzone with inducible elimination or overexpression of Rere or Fat3. Together these studies will lead to mechanistic insights into the relatively unexplored functions of the vertebrate Fat pathway in cell-cell communication and identify candidate genes for as yet unresolved causes of human congenital skeletal malformations.

描述（由申请人提供）：功能性骨骼系统取决于胚胎发育期间软骨和关节的协调发育。然而，人们对控制软骨大小、形状或连接的细胞和分子机制知之甚少。阐明引导间充质细胞凝聚和排列成前软骨形成堆叠的信号的进展对于阐明塑造骨骼组织和生长的早期事件特别重要。了解这些过程将有助于更好地诊断和治疗骨骼畸形和出生缺陷。此外，控制软骨形态发生和分化的分子对于改善软骨和关节损伤的治疗以及诱导干细胞形成软骨的生物工程努力可能具有相当大的临床重要性。我们最近发现，Rere是调节果蝇Dachsous（Dchs）-脂肪信号的转录因子Atrophin的近亲，是斑马鱼颅面发育所必需的，这暗示了 骨骼发生过程中平面细胞极性（PCP）中的脂肪通路。我们实验室的戏剧性结果现在证明了Fat 3在软骨分化中的更深远的作用，与PCP一致。Rere或Fat 3缺陷的胚胎发育软骨，其中在咽弓中堆叠和分化是分离的，这导致关节融合。此外，Rere和Fat 3在颅面发育过程中协调骨骼祖细胞对BMP和Fgf信号传导的反应至关重要。我们建议在三组实验中探索脂肪途径和PCP在软骨和关节形成中的作用。第一个目标将解决脂肪途径耦合软骨堆积和分化的假设。将使用实时成像在Rere和Fat 3突变体中评价软骨和关节表型。我们将鉴定软骨中脂肪的Dchs配体，并创建异位源以研究信号传播和调制。我们还将比较脂肪途径和Wnt/PCP的活动及其在软骨发育中的相互依赖性。第二个目标将解决脂肪途径协调对BMPs和其他生长因子的极化反应，从而将早期模式化事件与后期器官形成联系起来的假设。为此，我们有了新的细胞骨架极性和纤毛的标记，揭示了骨骼祖细胞极性的意外边界。最后，第三个目标将集中在关节形成和测试的假设，脂肪途径防止软骨堆积和分化的关节间区与诱导消除或过度表达的Rere或脂肪3。总之，这些研究将导致对脊椎动物脂肪通路在细胞间通讯中相对未探索的功能的机械见解，并确定人类先天性骨骼畸形尚未解决的原因的候选基因。