Shox2 and temporomandibular joint formation

Shox2 与颞下颌关节形成

基本信息

批准号：
7581991
负责人：
Yiping Chen
金额：
$ 35.39万
依托单位：
TULANE UNIVERSITY OF LOUISIANA
依托单位国家：
美国
项目类别：
财政年份：
2009
资助国家：
美国
起止时间：
2009-01-01 至 2013-12-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/7581991
关键词：
Ablation Accounting Adhesions Affect Alleles Animal Model Ankylosis Applications Grants Biological Assay Biological Models Breathing Cause of Death Cells Cephalic Chondrocytes Deglutition Deposition Development Disease Dyschondrosteosis Dysplasia EMSA Embryonic Development Enzymes Exhibits Fibrocartilages Genes Genetic Genetic Transcription Glenoid structure Goals Growth Head Heart Histones Homeobox Genes Human Hyaline Cartilage In Vitro Individual Joints Limb structure Link Mandible Mandibular Condyle Maxilla Mesenchymal Modification Molecular Morphogenesis Mus Mutant Strains Mice Mutate Mutation Neural Crest Oral cavity Osteogenesis Pattern Phenotype Phosphorylation Play Post-Translational Protein Processing Protein Dephosphorylation Protein Isoforms Proteins Relative (related person)Reporter Reporting Role Site Stem cells Surface Symptoms Syndrome Temporal bone structure Temporomandibular Joint Temporomandibular Joint Disorders Testing Transactivation Trauma Turner&apos s Syndrome Ubiquitin Undifferentiated United States Variant Wasting Syndrome capsule congenital infection feeding in vivo jaw movement mutant postnatal public health relevance

项目摘要

DESCRIPTION (provided by applicant): The temporomandibular joint (TMJ) ankylosis is clinically defined as limited mouth opening due to either a fibrous or bony union between the head of the condyle and the glenoid fossa. Although most incidents of TMJ ankylosis occur after trauma or an infection, congenital cases have been reported. Currently little is known about the TMJ morphogenesis and the underlying genetic, cellular and molecular mechanisms. Particularly, nothing is known about genetic alteractions that cause congenital TMJ ankylosis. The homeobox gene Shox2 is expressed specifically in the mesenchymal cells of the maxilla-mandibular junction and later in the immatured chondrocytes of the condyle of the TMJ. A conditional inactivation of Shox2 in cranial neural crest derived cells leads to dysplasia and ankylosis of the TMJ. Thus, Shox2 mutant mice serve as a unique model system for the studies of the mammalian TMJ development and its underlying mechanisms. We hypothesize that Shox2 plays a crucial role in TMJ development by regulating Runx2 expression directly. We also hypothesize that SUMO modification of Shox2a is essential for the TMJ formation. Four specific aims are proposed to test these hypotheses. In Aim 1, we will determine if Runx2 is a direct downstream target of Shox2 by reporter assay, EMSA and ChIP assay. We will also determine if phosphorylation impairs Shox2a's transactivating potency by creating mutant forms of Shox2a mimicking constitutively phosphorylation state or constitutively dephosphorylation state. In Aim 2, we will define SUMO modification of Shox2a and its consequences on the modulation of the Shox2a's transcriptional capacity. In this aim, we will further define the interaction between Shox2a and Histone 3.3, which may enhance the transcription capacity of Shox2a. The human SHOXa will be included in parallel in the proposed studies. In Aim 3, we will determine the role of SUMO modifcation of Shox2a in the TMJ development by expressing the mutated forms of Shox2a that either can not be sumoylated or mimic constitutively sumoylated status in the endogenous Shox2-expressing domains. In the last aim, we will test if human SHOX and SHOX2 are functionally redundant in embryonic development through targeted insertion of the human SHOX gene into the mouse Shox2 allele. PUBLIC HEALTH RELEVANCE: The temporomandibular joint (TMJ) ankylosis is one of the major symptoms of TMJ disorders that occur highly frequently humans. TMJ ankylosis is clinically characterized by the formation of bone or fibrous adhesion of the joint components, which restricts the jaw movement and causes difficulty in feeding, swallowing, and breathing. Congenital TMJ ankylosis have been repored, but very little is known about the underlying genetic alteractions. A conditional inactivation of the homeobox gene Shox2 in the TMJ cells in mice leads to abnormal formation and ankylosis of the TMJ. Thus the conditional Shox2 mutant mice provide a unique animal model for studying TMJ development and TMJ ankylosis. This proposal studies the role of Shox2 in the TMJ development and its functional mechanisms using in vitro and in vivo approaches. The results obtained from this study will provide fundamental information for our understanding of the formation and function of this unique joint in humans.

描述（由申请人提供）：颞下颌关节（TMJ）强直在临床上被定义为由于髁头和关节窝之间的纤维或骨性结合而导致张口受限。尽管大多数颞下颌关节强直发生在外伤或感染后，但也有先天性病例的报道。目前，人们对 TMJ 形态发生及其潜在的遗传、细胞和分子机制知之甚少。特别是，对于导致先天性颞下颌关节强直的遗传改变一无所知。同源盒基因Shox2在上颌骨-下颌交界处的间充质细胞中特异性表达，随后在TMJ髁突的未成熟软骨细胞中表达。颅神经嵴衍生细胞中 Shox2 的条件性失活会导致颞下颌关节发育不良和强直。因此，Shox2 突变小鼠可以作为研究哺乳动物颞下颌关节发育及其潜在机制的独特模型系统。我们假设 Shox2 通过直接调节 Runx2 表达在 TMJ 发育中发挥至关重要的作用。我们还假设 Shox2a 的 SUMO 修饰对于 TMJ 的形成至关重要。提出了四个具体目标来检验这些假设。在目标 1 中，我们将通过报告基因检测、EMSA 和 ChIP 检测确定 Runx2 是否是 Shox2 的直接下游靶标。我们还将通过创建模仿组成型磷酸化状态或组成型去磷酸化状态的 Shox2a 突变体形式来确定磷酸化是否会损害 Shox2a 的反式激活效力。在目标 2 中，我们将定义 Shox2a 的 SUMO 修饰及其对 Shox2a 转录能力调节的影响。为此，我们将进一步明确Shox2a和Histone 3.3之间的相互作用，这可能会增强Shox2a的转录能力。人类 SHOXa 将同时纳入拟议的研究中。在目标 3 中，我们将通过表达 Shox2a 的突变形式来确定 Shox2a 的 SUMO 修饰在 TMJ 发育中的作用，这些突变形式要么不能被 sumoylated，要么在内源 Shox2 表达域中模拟组成型 sumoylated 状态。在最后一个目标中，我们将通过将人 SHOX 基因定向插入小鼠 Shox2 等位基因来测试人 SHOX 和 SHOX2 在胚胎发育中是否具有功能冗余。公共卫生相关性：颞下颌关节 (TMJ) 强直是人类常见的 TMJ 疾病的主要症状之一。颞下颌关节强直的临床特点是关节部件形成骨质或纤维粘连，限制颌骨运动，导致进食、吞咽和呼吸困难。先天性颞下颌关节强直已有报道，但人们对潜在的遗传改变知之甚少。小鼠颞下颌关节细胞中同源框基因 Shox2 的条件性失活会导致颞下颌关节的异常形成和强直。因此，条件性 Shox2 突变小鼠为研究 TMJ 发育和 TMJ 强直提供了独特的动物模型。本提案利用体外和体内方法研究 Shox2 在 TMJ 发育中的作用及其功能机制。这项研究获得的结果将为我们了解人类这种独特关节的形成和功能提供基础信息。