Cellular and molecular mechanisms of orofacial clefts

项目总结/摘要 唇腭裂是最常见的出生缺陷之一，每年影响约22万新生儿。的 口面裂的原因和预防仍然知之甚少。我们发现Lrp 6介导的 Wnt/β-catenin信号通路是唇和腭形成和融合所必需的，它可能通过 Msx同源框基因的正调控，并可能抑制视黄酸的合成。 口面原基中的酶。口面发育涉及口面间充质扩张和 外胚层/上皮融合过程。我们证明了面部功能的丧失或获得 外胚层β-连环蛋白信号阻止了口面原基的形成和形成， 通过Fgf 8的转录调节，Fgf 8是面部外胚层和前部中的关键信号分子， 神经脊（区域信号中心）。腭裂致腭上皮β-连环蛋白功能缺失或获得 上颚这些研究表明，Wnt/β-catenin信号传导活性在正常的口面部过程中受到严格的调节， 形态发生以及Wnt/β-连环蛋白信号传导的低活性或高活性可能导致口面分娩 缺陷然而，Wnt/β-catenin信号通路在口面发育中的调控机制尚不清楚， 这几乎是未知的，将在本研究中讨论。口面裂可能是由基因突变引起的 和/或环境因素。后者可能会影响表观遗传过程，如DNA甲基化和 染色质修饰，以调节基因表达活性而不改变基因组序列。 然而，表观遗传机制的口面裂仍然知之甚少。我们假设 表观遗传因子调节唇/腭形成和融合的适当Wnt/β-连环蛋白信号传导活性。 具体目标1将解决两个表观遗传调节器的作用，如果他们不是，可能会导致口面裂 适当监管。具体目标2将测试关键Wnt/β-连环蛋白的遗传相互作用和/或遗传拯救， 信号成分和表观遗传因素在口面裂。具体目标3将检验以下假设： Wnt/β-连环蛋白信号传导的表观遗传调节可以防止突变动物模型中的口面裂。 成功完成拟议的研究将为遗传和表观遗传提供新的见解。 口面裂的机制，这可能转化为临床应用，以治疗口面出生缺陷 通过操纵关键的监管程序。

PROJECT SUMMARY/ABSTRACT Orofacial clefts are one of the most common birth defects, affecting about 220,000 newborns each year. The cause and prevention of orofacial clefts remain poorly understood. We have uncovered that the Lrp6-mediated Wnt/ß-catenin signaling pathway is required for lip and palate formation and fusion, which may act through positive regulation of the Msx homeobox-containing genes, and may repress a retinoic acid-synthesizing enzyme in the orofacial primordia. Orofacial development involves both orofacial mesenchymal expansion and ectodermal/epithelial fusion processes. We demonstrated that either loss- or gain-of-function of facial ectodermal ß-catenin signaling arrested the formation and patterning of orofacial primordia, which may act through transcriptional regulation of Fgf8, a critical signaling molecule in the facial ectoderm and anterior neural ridge (a regional signaling center). Loss- or gain-of-function of palatal epithelial ß-catenin caused cleft palate. These studies suggest that Wnt/ß-catenin signaling activity is tightly regulated during normal orofacial morphogenesis and that either hypo- or hyperactivity of Wnt/ß-catenin signaling may cause orofacial birth defects. However, the regulatory mechanism of Wnt/ß-catenin signaling pathway during orofacial development remains almost unknown and will be addressed in this study. Orofacial clefts can be caused by gene mutations and/or environmental factors. The latter may affect epigenetic processes, such as DNA methylation and chromatin modification, to regulate gene expression activities without altering the genomic sequence. Nevertheless, epigenetic mechanisms of orofacial clefts remain poorly understood. We hypothesize that epigenetic factors regulate appropriate Wnt/ß-catenin signaling activities for lip/palate formation and fusion. Specific Aim 1 will address the role of two epigenetic regulators that may lead to orofacial clefts if they are not properly regulated. Specific Aim 2 will test genetic interactions and/or the genetic rescue of key Wnt/ß-catenin signaling components and the epigenetic factors in orofacial clefts. Specific Aim 3 will test the hypothesis that epigenetic modulation of Wnt/ß-catenin signaling can prevent orofacial clefts in mutant animal models. Successful completion of the proposed research will provide new insights into the genetic and epigenetic mechanisms of orofacial clefts, which may translate into clinical applications to treat orofacial birth defects through manipulation of key regulatory processes.