Pharmacological rescue of tooth eruption disorders

项目总结/摘要 一个健康的牙列与适当功能的牙齿是必不可少的维持生活质量（QOL）。 涉及牙齿萌出的疾病很普遍，仅在恒牙中就高达2-4%。多颗臼齿 涉及严重病例，如罕见的原发性牙齿萌出失败（PFE）遗传条件，或更多 通常，双膦酸盐诱导的儿科患者的牙齿萌出停止， 损害患者有效咀嚼的能力。因为这些臼齿对 传统的正畸方法，需要创新的辅助疗法来恢复牙齿萌出， 影响磨牙更好的临床结果。牙齿萌出受牙囊细胞（DF）的调控 表达甲状旁腺激素相关蛋白（PTHrP）及其同源物 PTH/PTHrP受体（PTH 1 R）。PTHrP+ DF细胞中自分泌PTHrP-PTH 1 R信号传导的破坏导致 小鼠磨牙的牙齿萌出失败，与人类PFE状况非常相似。盐诱导 激酶（SIKs）是骨中PTH 1 R-cAMP/PKA信号传导的重要下游效应物，其中cAMP- 受调节的PKA依赖性SIK抑制是PTH合成代谢作用的关键组分。小分子 SIK抑制剂有望成为一种新的治疗策略，以增强受体中cAMP诱导的信号， 独立的方式。在这个建议中，我们假设PTH 1 R信号通路的激活是通过直接的 在遗传和免疫缺陷小鼠模型中，抑制SIK可以恢复有缺陷的磨牙萌出。 牙齿萌出障碍。在目标1中，我们将确定SIKs在PTHrP+牙科中的作用。 牙萌出中的滤泡细胞。我们假设SIKs调节PTHrP+ DF细胞的成骨细胞命运， 牙齿萌出我们将通过在PTHrP+ DF中有条件地删除这些基因来确定SIK 2/SIK 3的功能。 细胞在牙齿萌出的开始。我们将定义牙齿萌出的短期和长期变化， 使用组织学和3D microCT分析突变磨牙的牙根结构。在目标2中，我们将确定 抑制SIK在挽救磨牙PFE中的作用。我们假设抑制SIK可以挽救 由PTH 1 R缺陷遗传引起的臼齿萌出。我们将确定SIK的效果 PFE小鼠模型中的抑制，其中在PFE开始时PTHrP+ DF细胞中PTH 1 R被条件性缺失。 牙齿萌出我们将研究PFE表型是否可以通过伴随的损失而在遗传上得到拯救 用SIK 2/SIK 3抑制剂YKL-05-099抑制。在目标3中，我们将PTHrP定义为 双膦酸盐靶点和SIK抑制剂在挽救牙齿萌出中的作用。我们假设PTHrP- 在PTHrP+ DF细胞中，PTH 1 R信号传导响应于唑来膦酸（ZOL）而改变，并且ZOL诱导的PTH 1 R信号传导阻滞， 在磨牙中的牙齿萌出可以通过SIK抑制剂来挽救。我们将用YKL-05-治疗ZOL治疗的幼年小鼠 099抢救牙齿萌出。我们还将定义ZOL如何抑制PTHrP-PTH 1 R信号传导活动， SIK抑制剂是否逆转ZOL诱导的PTHrP信号转导和异常PTHrP+ DF细胞命运的改变。

Project Summary / Abstract A healthy dentition with appropriately functioning teeth is essential for maintaining quality of life (QOL). Disorders involving tooth eruption are prevalent, as high as 2–4% in permanent molars alone. Multiple molars are involved in severe cases such as rare genetic conditions of primary failure of tooth eruption (PFE) or, more commonly, bisphosphonate-induced arrest of tooth eruption in pediatric patients, which significantly compromise the patients' ability to chew effectively. Because these molars do not response well to conventional orthodontic approaches, innovative adjuvant therapies are needed to restore tooth eruption of affected molars for better clinical outcomes. Tooth eruption is regulated by cells in the dental follicle (DF) surrounding developing molars, which express parathyroid hormone-related protein (PTHrP) and its cognate PTH/PTHrP receptor (PTH1R). Disruption of autocrine PTHrP-PTH1R signaling in PTHrP+ DF cells causes failure of tooth eruption in murine molars that closely recapitulates the human PFE condition. Salt inducible kinases (SIKs) are an essential downstream effector of PTH1R-cAMP/PKA signaling in bone, in which cAMP- regulated PKA-dependent SIK inhibition is a key component of the anabolic actions of PTH. Small molecules SIK inhibitors hold promise as a novel therapeutic strategy to enhance cAMP-induced signals in a receptor- independent manner. In this proposal, we hypothesize that activation of the PTH1R signaling pathway by direct SIK inhibition can restore defective tooth eruption of molars in mouse models of genetically and pharmacologically induced tooth eruption disorders. In Aim 1, we will identify the roles of SIKs in PTHrP+ dental follicle cells in tooth eruption. We hypothesize that SIKs regulate osteoblast cell fates of PTHrP+ DF cells and tooth eruption. We will define the function of SIK2/SIK3 by conditionally deleting these genes in PTHrP+ DF cells at the onset of tooth eruption. We will define short-term and long-term alterations in tooth eruption and tooth root structures of mutant molars using histological and 3D microCT analyses. In Aim 2, we will determine the effects of SIK inhibition in rescuing PFE in molars. We hypothesize that SIK inhibition rescues failure of tooth eruption in molars genetically caused by PTH1R deficiency. We will determine the effects of SIK inhibition in a mouse model of PFE, in which PTH1R is conditionally deleted in PTHrP+ DF cells at the onset of tooth eruption. We will investigate whether PFE phenotypes can be rescued genetically by a concomitant loss of SIK2/SIK3, and pharmacologically by SIK inhibitor YKL-05-099. In Aim 3, we will define PTHrP as a bisphosphonate target and effects of SIK inhibitors in rescuing tooth eruption. We hypothesize that PTHrP- PTH1R signaling is altered in PTHrP+ DF cells in response to zoledronic acid (ZOL), and ZOL-induced arrest of tooth eruption in molars can be rescued by SIK inhibitors. We will treat ZOL-treated young mice with YKL-05- 099 to rescue tooth eruption. We will also define how ZOL inhibits PTHrP-PTH1R signaling activities, and whether SIK inhibitors reverse ZOL-induced alternation of PTHrP signaling and aberrant PTHrP+ DF cell fates.