Enamel biomineralization; the role of pH cycling

牙釉质生物矿化；

• 批准号: 10737481
• 负责人: Pamela K Den Besten
• 金额: $ 55.43万
• 依托单位: UNIVERSITY OF CALIFORNIA, SAN FRANCISCO
• 依托单位国家: 美国
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-03-07 至 2028-06-30
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10737481
• 关键词: AKT Signaling Pathway; Actins; Adhesions; Affect; Ameloblasts; Amelogenesis Imperfecta; Apical; Biocompatible Materials; Calcium; Cell Adhesion; Cell membrane; Cell physiology; Cells; Cellular Morphology; Code; Cytoskeleton; Defect; Dental Enamel; Dental caries; Developmental Process; Enamel Formation; Enamel Organ; Endocytosis; Environmental Risk Factor; Enzymes; Epigenetic Process; Epithelium; Esthetics; Etiology; Extracellular Matrix; FRAP1 gene; Fluorides; Focal Adhesions; Fracture; Gene Expression; Genes; Genetic; Goals; Human body; Hydrolysis; Hydroxyapatites; In Vitro; Integrins; Knowledge; Maintenance; Maturation-Stage Ameloblast; Mediating; Morphogenesis; PIK3CG gene; Pathway Analysis; Polymers; Predisposition; Process; Protein Secretion; Proteins; Proto-Oncogene Proteins c-akt; Recombinants; Regulation; Resistance; Risk Reduction; Role; Signal Transduction; Structure; System; Testing; Thinness; Time; Tissue Engineering; Tissues; Tooth structure; amelogenin; biomineralization; conditional knockout; crosslink; deamidation; enamel matrix proteins; extracellular; fluorosis; improved; in vivo Model; mTOR Signaling Pathway; mineralization; mouse model; mutant; novel; polymerization; protein structure; repaired; therapeutic protein; three dimensional cell culture; transcriptome; transglutaminase 2

PROJECT SUMMARY/ABSTRACT Mineralized enamel is the hardest tissue in the human body, and its proper formation is critical for the protection and maintenance of healthy teeth for a lifetime. Enamel biomineralization is directed by the epithelial-derived ameloblasts. Ameloblasts secrete enamel matrix proteins first, which are then hydrolyzed and replaced by hydroxyapatite crystals in the maturation process. During the maturation process, the pH of the enamel matrix modulates periodically to be acidic in approximately 80% of the maturation stage, with the remaining approximately 20% of the time remaining neutral. Maturation stage ameloblasts also modulate periodically along with the matrix pH cycling, changing cell morphology and functions. When pH cycling is disrupted by gene mutants or environmental factors that dysregulate ameloblast modulation, enamel maturation is dysregulated, resulting in hypomineralized, poorly formed enamel. However, the mechanisms that drive both matrix pH cycling and ameloblast modulation interactions are poorly understood. In preliminary studies, we found amelogenins can differentially affect cell morphology and adhesion in a pH-dependent manner; and ameloblast modulation is associated with changes in focal adhesion-P13k-AKT signaling pathways. Furthermore, we identified possible contributions of matrix pH to the function of the pH-dependent multifunctional enzyme, transglutaminase 2, in regulating amelogenin hydrolysis in the maturation of enamel matrix. In these proposed studies we will address the central hypothesis that enamel matrix pH regulates ameloblast function, protein structure, and matrix mineralization. We will use both in vitro and in vivo models with alterations in endocytosis, calcium transport, matrix hydrolysis and pH, to test our central hypothesis with the following specific aims. 1) To determine the effect of extracellular pH on adhesion and modulation of maturation stage ameloblasts; 2) To determine the effect of pH and calcium on integrin-mediated focal adhesion - PI3K-AKT-mTOR signaling pathways of ameloblasts; 3) To determine the significance of matrix pH on Transglutaminase 2 activity in the maturation stage enamel matrix. These studies will allow us to better understand the etiology of enamel hypomineralization, and they will allow us to apply this knowledge to reduce the risk of enamel defects. Furthermore, the findings from these studies will contribute to our long-term goal to identify strategies for enamel tissue bioengineering, repair, and the use of enamel proteins therapeutic purposes.

项目总结/摘要 矿化牙釉质是人体最坚硬的组织，其正确形成对于保护牙齿至关重要。 保持牙齿健康一辈子。牙釉质的生物矿化是由上皮来源的 造釉细胞成釉细胞首先分泌釉基质蛋白，然后将其水解并被 羟基磷灰石晶体在成熟过程中。在成熟过程中，釉质基质的pH值 在大约80%的成熟阶段周期性地调节为酸性， 大约20%的时间保持中立。成熟期成釉细胞也周期性地沿着 随着基质pH的循环，改变细胞形态和功能。当pH循环被基因破坏时， 突变体或环境因素使成釉细胞调节失调，釉质成熟失调， 导致低矿化、形成不良的釉质。然而，驱动基质pH循环的机制 和成釉细胞调节的相互作用知之甚少。在初步研究中，我们发现了釉原蛋白 可以不同程度地影响细胞形态和粘附的pH值依赖性的方式;和成釉细胞的调制， 与粘着斑-P13 k-AKT信号通路的变化相关。此外，我们还发现， 基质pH对pH依赖性多功能酶转氨酶2功能的贡献， 在釉质基质成熟过程中调节釉原蛋白水解。在这些拟议的研究中，我们将讨论 釉基质pH调节成釉细胞功能、蛋白质结构和基质的中心假设 成矿我们将使用内吞作用、钙转运， 基质水解和pH值，以测试我们的中心假设与以下具体目标。1)确定 细胞外pH对成熟期成釉细胞粘附和调节的影响; 2）确定 pH和钙对整合素介导的粘着斑的影响-PI 3 K-AKT-mTOR信号通路 3）确定基质pH对成釉细胞中转氨酶2活性的意义， 成熟阶段釉质基质。这些研究将使我们更好地了解牙釉质的病因 他们将使我们能够应用这些知识来降低釉质缺陷的风险。 此外，这些研究的结果将有助于我们确定釉质修复策略的长期目标。 组织生物工程，修复，以及利用牙釉质蛋白的治疗目的。

项目成果

Three-Dimensional Culture of Ameloblast-Originated HAT-7 Cells for Functional Modeling of Defective Tooth Enamel Formation.

• DOI: 10.3389/fphar.2021.682654
• 发表时间: 2021
• 期刊: Frontiers in pharmacology
• 影响因子: 5.6
• 作者: Földes A;Sang-Ngoen T;Kádár K;Rácz R;Zsembery Á;DenBesten P;Steward MC;Varga G
• 通讯作者: Varga G

Culturing and Scaling up Stem Cells of Dental Pulp Origin Using Microcarriers.

• DOI: 10.3390/polym13223951
• 发表时间: 2021-11-15
• 期刊: Polymers
• 影响因子: 5
• 作者: Földes A;Reider H;Varga A;Nagy KS;Perczel-Kovach K;Kis-Petik K;DenBesten P;Ballagi A;Varga G
• 通讯作者: Varga G