New Molecules and Cures for Tooth Agenesis

项目总结 牙列的发育是一个高度复杂的过程，涉及一系列相互作用的上皮组织- 间充质相互作用受5条保守的信号通路调控，即BMP、FGF3、WnT、EDA 还有嘘。这样一个精确的过程经常受到干扰并不令人惊讶。事实上，牙齿发育不全是 最常见的遗传性人类疾病，影响高达10%的人口，并施加显著的 患者及其家属的负担。PAX9是一种配对结构域转录因子，是一种 在牙间充质中特异表达，导致人类牙齿发育不全。Pax9在小鼠铅中的缺失 因此，它在牙间充质中起着关键的诱导作用。更好 理解Pax9在牙齿诱导期间充质中的分子作用 形态发生学为可造福牙齿患者的有形疗法的发展带来了希望 发育不全。我们对Pax9/牙齿器官的微阵列分析表明，Wnt信号基因是最明显的 随着BMPS、FGFs、Shh和EDA相关基因的改变。我们人类基因分析的结果和 来自其他组织的数据证实，WNT10A的突变是导致大多数人类病例的原因 牙齿发育不良。值得注意的是，我们的初步实验表明，当给予Wnt激动剂时 怀孕的Pax9+/-母亲，能够挽救突变的表型腭裂和牙齿停顿。尽管 这些进展对Pax9与Wnt的确切分子关系知之甚少 牙间充质中的信号通路以及这些基础科学知识如何被转化为新的 人类牙齿发育不全的治疗进展。综上所述，我们的数据为 将系统地检验Pax9是牙齿中信号事件的关键调节器的假说的研究 间充质在牙齿早期形态发生过程中对Wnt途径基因的调控作用。这个 因此，修复Pax9和Wnt10a突变牙间充质中的Wnt信号可能会使牙齿正常化 形态发生。AIM 1的研究将使用多管齐下的方法来提供关于分子的新数据 Pax9与调控牙间充质早期Wnt信号活性基因的关系 形态发生，因为这种关系没有BMP和成纤维细胞生长因子途径研究得那么好。目标2将 检测人类牙齿发育不全基因Pax9和Wnt10A突变如何影响其功能关系 这些基因导致牙齿发育受阻。目标3将确认Pax9的上游关系 通过评估体内给药时基于Wnt的新疗法是否可以纠正Pax9/牙齿 通过Wnt功能恢复的发育不全表型。来自这些基础科学和翻译的数据 研究将促进我们对牙间充质中信号分子的理解，并将提供 开发和测试恢复人类牙齿发育的非侵入性疗法的框架 受非综合征性牙齿发育不全的影响，这是一个具有高度临床相关性的重要问题，对于 是无法治愈的。

PROJECT SUMMARY The development of dentition is a highly complex process that involves a series of reciprocal epithelial- mesenchyme interactions that are regulated by five conserved signaling pathways, namely Bmp, Fgf, Wnt, Eda and Shh. That such a precise process is often perturbed is not surprising. Indeed, tooth agenesis is one of the most commonly inherited human disorders that affects up to 10% of the population and imposes significant burdens on patients and their families. Mutations in PAX9, a paired-domain transcription factor that is specifically expressed in dental mesenchyme, cause human tooth agenesis. The deletion of Pax9 in mice leads to tooth arrest at the bud stage, thus underscoring its key inductive role within dental mesenchyme. Better understanding the molecular actions of Pax9 in dental mesenchyme during the induction phase of tooth morphogenesis offers hope for the development of tangible therapies that can benefit patients with tooth agenesis. Our microarray analyses of Pax9-/- tooth organs show that Wnt signaling genes are most markedly altered along with the Bmps, Fgfs, Shh and Eda-related genes. The results of our human genetic analyses and data from other groups confirm that mutations in WNT10A are responsible for the majority of cases of human tooth agenesis. Significantly, our preliminary experiments suggest that Wnt agonists, when administered to pregnant Pax9+/- mothers, are able to rescue the mutant phenotype of cleft palate and tooth arrest. Despite these advances there is little understood about the precise molecular relationship of Pax9 with the Wnt signaling pathway in dental mesenchyme and how such basic science knowledge can be translated into new advances for the treatment of human tooth agenesis. Taken together, our data provide the framework for studies that will systematically test the hypothesis that Pax9 is a key modulator of signaling events in dental mesenchyme during early tooth morphogenesis through its regulation of genes in the Wnt pathway. The restoration of Wnt signaling in Pax9 and Wnt10a mutant dental mesenchyme is hence likely to normalize tooth morphogenesis. Aim 1 studies will use multipronged approaches to provide new data on the molecular relationship of Pax9 with genes that regulate Wnt signaling activities in dental mesenchyme during early morphogenesis since this relationship is not as well studied as that with the Bmp and Fgf pathways. Aim 2 will test how human tooth agenesis-causing mutations in Pax9 and Wnt10A affect the functional relationship of these genes to result in an arrest in tooth development. Aim 3 will confirm the upstream relationship of Pax9 by assessing whether novel Wnt-based therapeutics when administered in-vivo, can correct the Pax9-/- tooth agenesis phenotype through a restoration of Wnt function. Data from these basic science and translational studies will advance our understanding about the signaling molecules in dental mesenchyme and will provide the framework for developing and testing non-invasive therapies to restore tooth development in humans affected by non-syndromic tooth agenesis, an important problem of high clinical relevance and for which there are no cures.