Amelogenin Nanoribbons In Enamel Development And Engineering

釉原蛋白纳米带在牙釉质开发和工程中的应用

基本信息

批准号：
10597115
负责人：
Stefan Friedrich Habelitz
金额：
$ 66.7万
依托单位：
UNIVERSITY OF CALIFORNIA, SAN FRANCISCO
依托单位国家：
美国
项目类别：
财政年份：
2022
资助国家：
美国
起止时间：
2022-04-01 至 2027-03-31
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10597115
关键词：
3-Dimensional Acids Adopted Ameloblasts Amino Acid Sequence Amyloid Apatites Architecture Binding Biological Biology Biomimetics C-terminal Carrier Proteins Cryoelectron Microscopy Crystallization Data Dental Enamel Dentin Deposition Development Diameter Enamel Formation Engineering Epithelium Event Excision Extracellular Matrix Family suidae Fiber Film Fracture Future Growth Habits Histidine Human Hydrolysis In Situ In Vitro Ions Length Mastication Metalloproteases Methods Minerals Modeling Molecular Morphology Pattern Peptides Phase Phosphorylation Polymers Process Protein Secretion Proteins Proteolysis Recombinant Proteins Recombinants Resistance Resolution Role Series Specialized Epithelial Cell Structure Testing Thinness Tissues X ray diffraction analysis amelogenin beta pleated sheet biomineralization calcium phosphate copolymer design enamelin experimental study hydrophilicity in vitro Model mineralization molecular modeling mouse model nano nanofiber nanolithography nanomaterials nanometer scaffold self assembly three dimensional structure three-dimensional modeling

项目摘要

Enamel is the only epithelial derived tissue that mineralizes. It develops in an extracellular matrix secreted by highly specialized epithelial cells, the ameloblasts, which synthesizes a host of specific matrix proteins with little homology to any other known proteins. Amelogenin is by far the largest constituent of the developing enamel matrix (DEM) comprising ~90% of all secreted protein. Amelogenin’s primary structure encodes a series of critical functions of the DEM that ultimately allow for control over the uniaxial growth of apatite nanofibers and their three-dimensional organization into a stiff, hard and fracture-resistant tissue optimized for mastication and integration with the underlying dentin. Previously, we have demonstrated the biological significance of the amyloid-like character of amelogenin which allows the protein to adopt ß-sheet structure and to self-assemble into nanoribbons (Amel-NR) that guide the growth of mineral ribbons. Based on this data, a new model of enamel biomineralization founded on the activation of the mineralization process by the enzymatic cleavage of amelogenin by matrix metalloprotease-20 (MMP20) has been proposed and will be further evaluated in this application. We have hitherto shown, that removal of the hydrophilic C-terminal domain allowed an acidic polymer to interact with Amel-NRs thereby initiating the deposition of an amorphous calcium phosphate (ACP) layer. Subsequently, ACP transformed into crystalline apatite in the form of ribbon-like mineral about 15-20 nm wide that followed the morphology of the Amel-NRs. The sequential process of biomineralization observed in our in vitro model correlates with biological events of tissue mineralization and reinforces emerging concepts of biomineralization not only valid to enamel but other hard tissues. Such concepts include: a) biomineralization is regulated by proteolysis; b) presence of a carrier-protein that acts as a process-directing agent and delivers mineral ions to a self-assembled protein framework; c) carrier-protein interactions produce amorphous mineral deposits onto the protein framework; d) the supramolecular structure of the organic phase directs the phase transformation into defined crystal habits by oriented crystallization. In continuation of previous studies, we propose to identify constituents of the DEM that are critical for the templated growth of crystalline apatite nanofibers in association with the protein nanoribbons. By determining the three-dimensional structure of Amel-NRs at near-atomic resolution, further functional domains will be identified and associated with critical molecular and structural mechanisms in enamel formation. Ultimately, we plan to use the unique ability of Amel-NRs to direct the fibrous growth of apatite and synthesize nanomaterials through hierarchical design at the micro- and nanometer length scale.

牙釉质是唯一矿化的上皮来源组织，它在细胞外基质中发育。高度特化的上皮细胞，成釉细胞，可以合成大量特定的基质蛋白，几乎不需要与任何其他已知蛋白质具有同源性，釉原蛋白是迄今为止牙釉质发育中最大的成分。基质 (DEM) 占所有分泌蛋白的约 90%，其一级结构编码一系列关键蛋白。 DEM 的功能最终可以控制磷灰石纳米纤维的单轴生长及其将三维结构转化为僵硬、坚硬且抗断裂的组织，并针对咀嚼和咀嚼进行了优化与底层牙本质的整合之前，我们已经证明了其生物学意义。牙釉蛋白的淀粉样蛋白样特征，使蛋白质能够采用 ß-片结构并进行自组装纳米带（Amel-NR）可引导矿物带的生长基于此数据，一种新的牙釉质模型。生物矿化建立在通过酶裂解激活矿化过程的基础上已提出由基质金属蛋白酶 20 (MMP20) 产生的釉原蛋白，并将在此进一步评估迄今为止，我们已经证明，去除亲水性 C 端结构域可以产生酸性。聚合物与 Amel-NR 相互作用，从而引发无定形磷酸钙 (ACP) 的沉积随后，ACP 转化为约 15-20 nm 的带状矿物形式的结晶磷灰石。广泛遵循 Amel-NR 的形态，观察到生物矿化的顺序过程。我们的体外模型与组织矿化的生物事件相关，并强化了新兴概念生物矿化不仅适用于牙釉质，也适用于其他硬组织。这些概念包括： a) 生物矿化是。受蛋白水解调节；b) 存在充当过程导向剂并传递的载体蛋白矿物质离子形成自组装蛋白质框架；c) 载体-蛋白质相互作用产生无定形矿物质沉积到蛋白质框架上；d) 有机相的超分子结构引导相通过定向结晶转变为确定的晶体习性。继续之前的研究，我们建议确定 DEM 的组成部分，这些组成部分对于通过确定与蛋白质纳米带相关的结晶磷灰石纳米纤维的模板生长。在近原子分辨率下的 Amel-NR 的三维结构，进一步的功能域将是最终，我们确定了牙釉质形成的关键分子和结构机制并与之相关。计划利用Amel-NRs的独特能力来引导磷灰石的纤维状生长并合成纳米材料通过微米和纳米长度尺度的分层设计。