Dental Follicle: A Central Regulator of Tooth Eruption and Root Formation

牙囊：牙齿萌出和牙根形成的中央调节器

• 批准号: 9598677
• 负责人: Wanida Ono
• 金额: $ 15.6万
• 依托单位: UNIVERSITY OF MICHIGAN AT ANN ARBOR
• 依托单位国家: 美国
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-06-09 至 2020-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9598677
• 关键词: Affect; Alleles; Alveolar; Ankylosis; Candidate Disease Gene; Cell Culture System; Cell Culture Techniques; Cell Line; Cells; Cementoblast; Characteristics; Communication; Computer Retrieval of Information on Scientific Projects Database; Coupling; Data; Dental Sac; Development; Disease; Energy Intake; Esthetics; Expression Profiling; Face; Failure; Foundations; Future; Gene Expression; Gene Targeting; General Population; Genes; Growth and Development function; Heterogeneity; Human; Hypercementosis; In Situ; In Vitro; Individual; Inferior; Innovative Therapy; Intervention; Knowledge; LoxP-flanked allele; Mastication; Mesenchymal; Mesenchymal Stem Cells; Modality; Modeling; Molecular; Molecular Analysis; Morbidity - disease rate; Mus; Orthodontic; Osteoblasts; Osteoclasts; Parathyroid Hormone Receptor; Pathway interactions; Patients; Periodontal Ligament; Pharmacology; Phenotype; Plant Roots; Play; Property; Prosthesis; Quality of life; Receptor Gene; Receptor Signaling; Role; Signal Pathway; Speech; Stem cells; Tamoxifen; Technology; Tissues; Tooth Diseases; Tooth Extraction; Tooth eruption; Tooth root structure; Tooth structure; Transgenic Organisms; Validation; alveolar bone; base; bone; clinical application; comparative; experimental study; genetic signature; in vivo; loss of function mutation; mechanical force; mouse model; mutant; novel; nutrition; parathyroid hormone-related protein; progenitor; receptor; self-renewal; single-cell RNA sequencing; therapeutic target; transcription factor; transcriptome sequencing

PROJECT SUMMARY/ABSTRACT Tooth eruption is essential for survival of humans, with direct impact on the fundamental functions such as growth and development of the lower face, mastication for nutrition/energy intake, speech and esthetics for effective communication. Disorders involving tooth eruption are prevalent among the general public in a variety of forms such as delayed, ectopic and failure of eruption (2~4% for permanent molars). Many of these affected teeth do not respond well to orthodontic mechanical forces, often resulting in ankylosis. Extraction of these teeth results in morbidity and subsequently requires prostheses with inferior function, thus compromising patients' quality of life. Thus, more effective modalities to facilitate or reactivate tooth eruption are needed. The dental follicle (DF) surrounding the developing tooth coordinates tooth eruption and root formation. DF facilitates formation of osteoclasts that resorb alveolar bones to create the eruption pathway, and includes mesenchymal progenitor cells for cementoblasts and periodontal ligament (PDL) cells. These DF progenitor cells are crucial for development of periodontal tissues, which are particularly important for the later stage of tooth eruption. As loss-of-function mutations in PTH/PTHrP receptor (PPR) cause primary failure of tooth eruption (PFE) in humans, a PPR-dependent mechanism regulating DF progenitor cells is likely to play important roles for the coupling of tooth eruption and root formation. In this project, we hypothesize that DF progenitor cells are the central regulators of tooth eruption and root formation, whereby PTHrP-PPR signaling exerts important regulatory roles to maintain their unique properties of these cells. In Aim1, we will determine molecular characteristics of dental follicle progenitor cells in vivo. The working hypothesis is that DF cells express a unique set of transcription factors that maintain their properties as mesenchymal progenitor cells. Using the DF-specific PTHrP-creER transgenic line, we will define the gene expression profiles of individual DF progenitor cells based on a single cell RNA-seq analysis, followed by in situ validation of these genes. Further, we will establish a cell culture model to investigate heterogeneity and properties of DF progenitor cells through clonal selection and characterization. In Aim2, we will define roles of the PTH/PTHrP receptor in DF progenitor cells in tooth eruption. The working hypothesis is that PTHrP-PPR signaling in DF progenitor cells is essential to maintain their ability to self-renew and differentiate into periodontal ligament (PDL) cells. Using the mouse PFE model we have successfully established, we will determine the impact of PPR-deficiency on cell fate decision and self-renewal of DF progenitor cells using ex vivo cell culture systems. Further, using a comparative RNA-seq analysis, we will identify PPR-target genes responsible for the mouse PFE phenotypes in which tooth eruption is uncoupled from root formation. As a future research plan, we will further investigate key molecular mechanisms that regulate cell fate decisions of DF progenitor cells. We will particular focus on transcription factors downstream of PPR signaling.

项目概要/摘要 牙齿萌出对于人类的生存至关重要，直接影响到以下基本功能： 下面部的生长和发育、营养/能量摄入的咀嚼、言语和美观 有效的沟通。涉及牙齿萌出的疾病在各种人群中普遍存在 萌出延迟、异位和失败等形式（恒磨牙为 2~4%）。其中许多受到影响 牙齿对正畸机械力反应不佳，常常导致关节强直。提取这些 牙齿会导致发病，随后需要功能较差的假牙，从而损害 患者的生活质量。因此，需要更有效的方式来促进或重新激活牙齿萌出。这 正在发育的牙齿周围的牙囊（DF）协调牙齿的萌出和牙根的形成。 DF 促进破骨细胞的形成，吸收牙槽骨以创建萌出途径，包括 成牙骨质细胞和牙周膜 (PDL) 细胞的间充质祖细胞。这些 DF 祖 细胞对于牙周组织的发育至关重要，这对于牙周组织的后期尤为重要 牙齿萌出。由于 PTH/PTHrP 受体 (PPR) 的功能丧失突变导致牙齿原发性衰竭 在人类皮疹（PFE）中，调节 DF 祖细胞的 PPR 依赖性机制可能发挥作用 在牙齿萌出和牙根形成的耦合中发挥着重要作用。在这个项目中，我们假设 DF 祖细胞是牙齿萌出和牙根形成的中央调节因子，通过 PTHrP-PPR 信号传导 发挥重要的调节作用以维持这些细胞的独特特性。在目标 1 中，我们将确定 体内牙囊祖细胞的分子特征。工作假设是 DF 细胞 表达一组独特的转录因子，保持其作为间充质祖细胞的特性。 使用 DF 特异性 PTHrP-creER 转基因系，我们将定义个体 DF 的基因表达谱 基于单细胞 RNA-seq 分析的祖细胞，然后对这些基因进行原位验证。更远， 我们将建立细胞培养模型来研究 DF 祖细胞的异质性和特性 克隆选择和表征。在 Aim2 中，我们将定义 PTH/PTHrP 受体在 DF 祖细胞中的作用 牙齿萌出时的细胞。目前的假设是 DF 祖细胞中的 PTHrP-PPR 信号传导至关重要 维持其自我更新和分化为牙周膜（PDL）细胞的能力。使用鼠标 我们已经成功建立了PFE模型，我们将确定PPR缺陷对细胞命运的影响 使用离体细胞培养系统进行 DF 祖细胞的决策和自我更新。此外，使用 比较 RNA-seq 分析，我们将鉴定负责小鼠 PFE 表型的 PPR 靶基因 其中牙齿萌出与牙根形成无关。作为未来的研究计划，我们将进一步研究 调节 DF 祖细胞命运决定的关键分子机制。我们将特别关注 PPR 信号下游的转录因子。