Wnt5a/Ror2 Signaling in Jaw Bone Development

项目摘要 我们的长期目标是发现新的基于分子的治疗方法来调节骨的大小，作为一种手段， 解决颅面畸形的非手术治疗需求。关于精确的 在生长和发育过程中控制颌骨大小的分子机制。这种知识的缺乏使 牵引成骨作为少数几个可用的干预措施之一，以改变颌骨的大小，即使骨的 众所周知，用这种技术操纵面部比操纵长骨困难得多。治疗程序 颌骨大小的差异将大大受益于更广泛的知识基础的分子和细胞机制 控制下颚大小本研究的目的是通过了解如何建立这一目标， 颅神经嵴（CNC），形成面部和颌骨的所有元素，调节颌骨的大小。到 为了解决这个问题，我们建议在体内操纵CNC，这是一个高度可接近的胚胎群体。为 例如，我们可以将鹌鹑供体CNC移植到鸭子宿主中，这会产生嵌合体quck; 鸭供体CNC进入鹌鹑宿主，产生嵌合双抗体。利用不同的发展项目 提供了一种独特的方式来操纵CNC和相邻宿主组织之间的信号传导， 允许发现依赖于CNC的进程。一些研究小组研究了控制性颌骨中的骨沉积 但我们的数据表明，中胚层来源的破骨细胞参与CNC- 衍生的骨细胞在发育的后期控制颌骨的大小。我们以前已经表明，CNC控制 颌骨大小，骨吸收由CNC控制，骨吸收控制颌骨大小。如何CNC 完成如此复杂的任务，以及什么因素足以复制这种现象，是未知的。 可能的候选者可以包括WNT 5A/ROR 2非经典信号传导的成员和靶标，因为它们是 已知在骨吸收过程中起关键作用。因此，我们假设通过调节WNT 5A/ROR 2， 非经典信号，CNC指导骨吸收以控制颌骨大小。为了验证我们的假设，我们 提出了两个互补和高度翻译的具体目标。具体目标1将确定机制 CNC-derived osteocytes and mesodermally-derived osteocytes act via WNT5A/ROR2 non-canonical 发出信号以再吸收骨并调节颌骨大小。具体目标2将确定机制， CNC通过WNT 5A/ROR 2非经典信号调节破骨细胞介导的骨的作用 吸收来调节颌骨大小。我们将采用功能获得和功能丧失技术来鉴定 赋予CNC控制下颌骨发育能力的机制。通过确定 破骨细胞和骨细胞控制骨吸收的精确机制，未来的研究将能够 开发精确的治疗方法来控制下颌骨的发育。

PROJECT SUMMARY Our long-term goal is to discover novel molecular-based therapies for regulating the size of bone as a means to address the need for non-surgical treatments of craniofacial malformations. Little is known regarding the precise molecular mechanisms controlling jaw size during growth and development. This lack of knowledge leaves distraction osteogenesis as one of the few available interventions to change jaw size, even though bones of the face are known to be much more difficult to manipulate with this technique than long bones. Procedures to treat jaw size disparities will greatly benefit from a broader knowledge base of molecular and cellular mechanisms that control jaw size. The objective of the current study is to build toward this goal by understanding how the cranial neural crest (CNC), which forms all the elements in the facial and jaw skeletons, regulates jaw size. To address this issue, we propose to manipulate in vivo the CNC, a highly accessible embryonic population. For example, we can transplant quail donor CNC into a duck host, which creates a chimeric quck; and we transplant duck donor CNC into the quail host, generating chimeric duail. Exploiting the divergent developmental programs of quail and duck provides a unique way to manipulate signaling between CNC and adjacent host tissues and allows discovery of CNC-dependent processes. Some groups have looked at bone deposition in controlling jaw size, but our data suggest that bone resorption by mesodermally-derived osteoclasts with participation of CNC- derived osteocytes control jaw size at later stages of development. We have previously shown that CNC controls jaw size, bone resorption is controlled by CNC and that bone resorption controls jaw size. How CNC accomplishes such a complex task, and what factors are sufficient to replicate this phenomenon, is unknown. Likely candidates may include members and targets of WNT5A/ROR2 noncanonical signaling, since they are known to play critical roles during bone resorption. Therefore, we hypothesize that by modulating WNT5A/ROR2 non-canonical signaling, CNC directs bone resorption to control jaw bone size. To test our hypothesis, we propose two complementary and highly translational Specific Aims. Specific Aim 1 will determine the mechanism by which CNC-derived osteocytes and mesodermally-derived osteoclasts act via WNT5A/ROR2 non-canonical signaling to resorb bone and regulate jaw bone size. Specific Aim 2 will determine the mechanism via which CNC acts by WNT5A/ROR2 noncanonical signaling to regulate the actions of osteoclast-mediated bone resorption to regulate jaw bone size. We will employ gain- and loss-of-function techniques to identify molecular mechanisms that endow CNC with the ability to control mandibular bone development. By determining the precise mechanism of control of bone resorption by osteoclasts and osteocytes, future studies will be able to develop accurate therapies to control lower jaw bone development.