Genetic Determinants of Physiological Responses to Fluoride in Bone

描述(由申请人提供)：各种化学形式和暴露的氟化物已多次被证明对骨基质和骨细胞(成骨细胞和破骨细胞)有作用。氟化物的合成代谢特性曾被用于治疗绝经后骨质疏松症。过量的全身性氟可导致软组织(如韧带)钙化、骨质硬化、骨质疏松和骨软化症，这可能会损害骨骼质量和强度，导致氟骨症。尽管有丰富的科学文献，但在了解氟化物对骨细胞作用的分子机制方面仍存在知识空白。我们假设，编码蛋白质和参与骨骼内稳态的途径的遗传决定因素是氟化物对骨细胞及其造血祖细胞作用的基础。通过扩展表型分析，我们确定了近交系小鼠之间在破骨细胞形成方面的差异，从而支持了遗传背景的贡献。本研究的目标是利用全基因组方法在动物模型中识别氟化物反应基因座，具体目标如下：SpA1：将以C57BL/6J和C3H/HeJ近交系小鼠为祖先品系，通过两代杂交进行数量性状基因座(QTL)定位，以产生一组F2后代。F2小鼠将接受在饮用水中添加或不添加氟化物的治疗。将进行多参数表型：骨形成/吸收的血清生物标志物；体外破骨细胞生成和成骨祖细胞分析；以及体外造血(CFC)分析。此外，选定的骨骼将进行BMD(微CT)表型分析。基因组扫描的平均SNP密度在常染色体上为3Mb，在Chr上为7Mb。将执行X，然后使用各种区间作图方法进行遗传分析。SpA2：首先，利用上面的表型和氟化物处理方案，确定家系和野生型近交系小鼠品系之间的氟化物反应差异。第二，在电子地图战略中执行。广泛和长期的目标是在动物模型中以及后来在人类中识别和表征对氟反应的遗传变异，例如多态。公共卫生意义：该项目的目标是在动物模型中识别对氟化物敏感的染色体区域。长期目标是在动物模型中表征对氟反应的遗传变异，识别那些易受氟作用不必要的或潜在的不利影响的高危人群，并阐明氟影响生物矿化的基本机制。这个动物研究项目将产生与骨质疏松症和氟骨症等公共卫生问题相关的可解释和有用的信息。

DESCRIPTION (provided by applicant): Fluoride in various chemical forms and exposures has been repeatedly shown to have actions on bone matrix and on bone cells (osteoblasts and osteoclasts). The anabolic properties of fluoride were once explored for use in the treatment of postmenopausal osteoporosis. Excessive systemic fluoride can result in calcification of soft tissues (e.g. ligaments), osteosclerosis, osteoporosis, and osteomalacia which can compromise bone quality and strength leading to skeletal fluorosis. Despite a wealth of scientific literature a gap of knowledge exists in understanding the molecular mechanisms of fluoride actions on bone cells. We posit that genetic determinants that encode proteins and pathways involved in bone homeostasis underlie fluoride actions on bone cells and their hematopoietic precursors. Using extended phenotyping, we identified differences in osteoclastogenesis between inbred mouse strains, thus supporting the contribution of genetic background. The goal of the proposed studies, to identify fluoride responsive genetic loci in an animal model using a whole genome approach, will be pursued in the following Specific Aims: SpA1: Quantitative trait loci (QTL) mapping will be performed using C57BL/6J and C3H/HeJ inbred mice as progenitor strains in a two generation cross to produce a panel of F2 progeny. F2 mice will be treated with or without fluoride in their drinking water. Multiparameter phenotyping will be performed: serum biomarkers of bone formation/resorption; ex vivo osteoclastogenesis and osteoprogenitor assays; and ex vivo hematopoietic (CFC) assays will be performed. Additionally, selected bones will be phenotyped for BMD (microCT). A genome scan with an average SNP density of 3 Mb across the autosomes and 7 Mb across Chr. X will be performed followed by genetic analyses using a variety of interval mapping methods. SpA2: First determine fluoride response variation among a collection of domestic and wild type inbred mouse strains utilizing the phenotyping and fluoride treatment protocol above. Second, perform in silico mapping strategies. The broad and long term objectives are to identify and characterize fluoride responsive genetic variations, e.g. polymorphisms, in an animal model and later in humans. Public Health Significance: The goal of this project is to identify fluoride responsive chromosomal regions in an animal model. The long term goals are to characterize fluoride responsive genetic variations in an animal model, to identify those at risk populations who are susceptible to the unwanted or potentially adverse effects of fluoride action, and to elucidate fundamental mechanisms by which fluoride affects biomineralization. This animal studies project will generate interpretable and useful information relevant to public health issues like osteoporosis and skeletal fluorosis.