Role of the Ciliary Protein C2CD3 in Mandibular Skelotogenesis

项目概要/摘要 初级纤毛是一种非运动的、以微管为基础的细胞器，从细胞膜上伸出， 细胞的外部环境，并协调多个信号转导途径。中断 初级纤毛的结构或功能导致一类称为纤毛病的疾病。骨架通常 在纤毛病中受到影响，因为纤毛病患者经常出现骨软骨发育不良（OCDPs）- 骨和软骨-如小颌畸形和下颌畸形。口面指综合征是一种 出现几种OCDP的纤毛病子集。有相当大的表型重叠之间 口腔-面部-手指综合征的亚型和其他骨骼纤毛病，使他们难以正确地 诊断和区分彼此。纤毛病变的表型重叠程度很大， 影响骨骼，加上缺乏治愈纤毛病OCDPs的方法，使这成为一个重要的问题， 生物医学方面的问题。这项工作的重点是了解纤毛蛋白C2cd 3的需求 在利用禽C2CD 3突变体talpid 2（ta 2）和 条件C2cd 3fl/fl小鼠。C2cd 3定位于初级纤毛的远端中心粒， 纤毛发生C2cd 3突变导致人类纤毛病变口面指综合征亚型14。我 初步数据表明，talpid 2胚胎存在许多下颌骨OCDP，如双侧 麦克尔软骨发育不良和发育不良的骨骼元素。至于如何做到这一点，还有待深入研究 出现这些表型。在目标1中，我将确定双侧Meckel软骨发育不良是否为外生骨疣- 软骨帽骨肿瘤定义为缺乏细胞极性和纤毛延伸，Ext 1/2减少 表达，并减少硫酸乙酰肝素合成。ta 2胚胎也具有增加的FGF 8表达， 发育中的下颌骨，但不知道这是否会导致下颌骨发育不全。目标2，我会 确定扩增的下颌骨FGF 8信号传导是否足以诱导ta 2下颌骨骨骼发育不全， 鸟类下颌骨发育中的珠状突起。最后，C2cd 3在整个细胞中普遍表达。 发育中的胚胎，并且不知道颅面上皮或间充质中C2cd 3的缺失是否导致 下颌骨OCDP。对于目标3，我将用dHAND-Cre和Crect小鼠繁殖C2cd 3fl/fl小鼠，以条件性地 删除下颌间充质和上皮中的C2cd 3，以确定C2cd 3是否在任一组织类型中丢失 会导致下颌骨强迫症这项研究对于促进我们对细胞和 睫状体病患者下颌骨OCDPs的分子病因学研究更好地理解发展 研究下颌骨OCDPs在睫状体病中的作用机制对于进一步完善诊断和发展 低侵入性的治疗选择。

Project Summary/Abstract Primary cilia are non-motile, microtubule-based organelles that protrude from the cellular membrane to sense the cell’s external environment and to coordinate the transduction of multiple signaling pathways. Disruptions in the structure or function of primary cilia result in a class of disorders known as ciliopathies. The skeleton is often affected in ciliopathies as ciliopathy patients often present with osteochondrodysplasias (OCDPs) - anomalies of bone and cartilage - such as micrognathia and mandibular dysmorphology. Oral-facial-digital syndromes are a subset of ciliopathies that present with several OCDPs. There is considerable phenotypic overlap between subtypes of oral-facial-digital syndromes and among other skeletal ciliopathies, making them difficult to properly diagnose and differentiate from each other. The substantial degree of phenotypic overlap of ciliopathies that affect the skeleton combined with the lack of a cure for ciliopathic OCDPs make this an issue of significant biomedical concern. This proposed work focuses on understanding the requirement of the ciliary protein C2cd3 during the development of the mandibular skeleton by utilizing the avian C2CD3 mutant talpid2 (ta2) and the conditional C2cd3fl/fl mouse. C2cd3 localizes to the distal centrioles of primary cilia and is required for ciliogenesis. Mutations in C2cd3 result in the human ciliopathy Oral-facial-digital syndrome subtype 14. My preliminary data indicates that talpid2 embryos present with numerous mandibular OCDPs, such as bilateral Meckel’s chondrodysplasias and hypoplastic skeletal elements. There has yet to be an in-depth study as to how these phenotypes arise. In Aim 1, I will determine if the bilateral Meckel’s chondrodysplasias are exostoses - cartilage-capped bony tumors defined by lack of cellular polarity and ciliary extension, reduced Ext1/2 expression, and reduced heparan sulfate synthesis. ta2 embryos also possess increased FGF8 expression in the developing mandible, but it is not known if this leads to mandibular bone hypoplasia. For Aim 2, I will determine if expanded mandibular FGF8 signaling is sufficient to induce ta2 mandibular skeletal hypoplasia using bead implantations in the developing avian mandible. Lastly, C2cd3 is expressed ubiquitously throughout the developing embryo and it is not known if loss of C2cd3 in the craniofacial epithelium or mesenchyme leads to mandibular OCDP. For Aim 3, I will breed C2cd3fl/fl mice with the dHAND-Cre and Crect mice to conditionally delete C2cd3 in the mandibular mesenchyme and epithelium to determine if C2cd3 loss in either tissue type results in mandibular OCDP. This study is important for advancing our understanding of the cellular and molecular etiology of mandibular OCDPs in ciliopathic patients. A greater understanding of the developmental mechanisms of mandibular OCDPs in ciliopathies is necessary for further refined diagnosis and the development of less invasive therapeutic options.