Calcium Control of Enamel Development

牙釉质发育的钙控制

• 批准号: 9493459
• 负责人: Rodrigo S. Lacruz
• 金额: $ 39.63万
• 依托单位: NEW YORK UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-06-07 至 2021-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9493459
• 关键词: Address; Adult; Affect; Agonist; Ameloblasts; Amelogenesis Imperfecta; Animals; Biological Process; Birth; Buffers; Calcineurin; Calcium; Caries prevention; Cells; Cellular Stress; Clinical; Data; Defect; Dental Enamel; Development; Down Syndrome; Dyes; Electron Microscopy; Elements; Enamel Formation; Endoplasmic Reticulum; Environment; Frequencies; Fura-2; Gene Expression; Gene-Modified; Genes; Genetic Diseases; Goals; Growth; Hardness Tests; Health; Histologic; Homeostasis; Hour; Human Genetics; ITPR1 gene; Inositol; Knockout Mice; Knowledge; Lead; Link; Measurement; Mediating; Minerals; Monitor; Mus; Mutation; NFAT Pathway; Oral; Organ; Pathway interactions; Patients; Pattern; Physiological; Preventive; Process; Proteins; Reporting; Role; Second Messenger Systems; Skin; Sweat Glands; Testing; Tissues; Tooth Diseases; Tooth structure; Western Blotting; Work; ameloblastin; biophysical techniques; bone; calcification; experimental study; gene function; inhibitor/antagonist; interest; microCT; mineralization; oral bacteria; overexpression; paralogous gene; public health relevance; ratiometric; receptor

 DESCRIPTION (provided by applicant): Calcium (Ca2+) is a key regulator of a broad range of biological functions and is also a key element in the composition of dental enamel. Ca2+ must reach the forming enamel layer but how this process is regulated in ameloblasts is poorly understood. Our goal is to identify key pathways used by ameloblasts to regulate Ca2+ dynamics, in particular the required mechanisms for Ca2+ entry and pathways activated upon increases in cytosolic Ca2+ concentration. Deficiencies in the normal functioning of these pathways result in abnormal enamel that is prone to dental disease which can act as a host environment for oral bacteria. The focus of this proposal is to identify the functions of the store operated Ca2+ release-activated Ca2+ (CRAC) channels in enamel development. CRAC channels comprise important Ca2+ influx mechanisms activated following Ca2+ release from the endoplasmic reticulum (ER). The importance of Ca2+ influx via CRAC channels pathway in ameloblasts is understood by clinical reports describing hypo-calcified amelogenesis imperfecta in patients with mutations to STIM1 and ORAI1. However our understanding of CRAC channels function in enamel is limited as Stim1-/- and Orai1-/- animals die around birth. To address this problem, we developed several conditional knockout mice that specifically analyze the function of CRAC channels with particular reference to dental enamel formation. The ensuing Ca2+ entry via CRAC activates the calcineurin-NFAT pathway, which up-regulates the regulator of calcineurin (RCAN1). Although we find that NFAT and RCAN1 are expressed in enamel cells, and that this pathway is active during enamel development, the functions of these genes in enamel development are unknown. We are particularly interested in RCAN1 as Down syndrome patients present with a host of enamel deficiencies including abnormal mineralization and thinner enamel. Down syndrome is one of the most common human genetic disorders (frequency is 1 in ~700 births) characterized by elevated levels of RCAN1 in several tissues. The cause of growth alterations in the enamel of Down syndrome patients remains unknown. Our proposed studies will increase our understanding of enamel development. Such knowledge will impact caries prevention and has broader implications in bone homeostasis/development and in the development of ectodermal organs as some of these pathways are shared. The proposed work will also lead to a better understanding of systemic effects of CRAC channel function.

 说明(申请人提供)：钙(钙)是一系列生物功能的关键调节剂，也是牙釉质组成的关键元素。钙离子必须到达形成釉质层，但这一过程在成釉细胞中是如何调节的，人们知之甚少。我们的目标是确定成釉细胞用来调节钙动态的关键途径，特别是钙进入所需的机制和细胞内钙浓度增加时激活的途径。这些途径正常功能的缺陷会导致牙釉质异常，容易患上牙病，这可能是口腔细菌的宿主环境。这项建议的重点是确定商店的功能 在釉质发育中操纵钙释放激活的钙通道(CRAC)。CRAC通道包括内质网(ER)释放钙后激活的重要钙内流机制。在STIM1和ORAI1突变的患者中，临床报告描述了低钙化的成釉不全，了解了成釉细胞中通过CRAC通道钙内流的重要性。然而，我们对釉质中CRAC通道功能的了解有限，因为STIM1-/-和Orai1-/-动物在出生时就会死亡。为了解决这个问题，我们开发了几种条件基因敲除小鼠，专门分析CRAC通道的功能，特别是与牙釉质形成有关的功能。随后通过CRAC的钙离子进入激活了钙调神经磷酸酶-NFAT通路，该通路上调了钙调神经磷酸酶(RCAN1)的调节。虽然我们发现NFAT和RCAN1在釉质细胞中表达，并且这一途径在釉质发育过程中是活跃的，但这些基因在釉质发育中的功能尚不清楚。我们对RCAN1特别感兴趣，因为唐氏综合症患者存在大量的釉质缺陷，包括异常矿化和更薄的釉质。唐氏综合征是最常见的人类遗传性疾病之一(发病率为1/700)，其特征是几个组织中RCAN1水平升高。唐氏综合症患者牙釉质生长改变的原因尚不清楚。我们提出的研究将增加我们对牙釉质发育的了解。这些知识将影响龋齿的预防，并在骨骼内稳态/发育和外胚层器官的发育方面具有更广泛的影响，因为这些途径中的一些是共享的。所提出的工作也将有助于更好地理解CRAC通道功能的系统效应。