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被反复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。全身氟化物过量可导致软组织（如韧带）钙化、骨硬化、骨质疏松和骨软化，从而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存在知识差距。我们假设编码蛋白质的遗传决定因素和参与骨稳态的途径是氟化物对骨细胞及其造血前体的作用的基础。利用扩展表型，我们确定了近亲繁殖小鼠品系之间破骨细胞发生的差异，从而支持遗传背景的贡献。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位点，具体目标如下：SpA1：将C57BL/6J和C3H/HeJ自交系小鼠作为祖系，在两代杂交中进行数量性状位点（QTL）定位，以产生一组F2后代。2只小鼠分别在饮水中添加或不添加氟化物。将进行多参数表型分析：骨形成/吸收的血清生物标志物；体外破骨细胞和成骨细胞测定；和体外造血（CFC）测定将进行。此外，选择的骨骼将进行骨密度表型分析（microCT）。基因组扫描显示，常染色体的平均SNP密度为3mb， Chr的平均SNP密度为7mb。X将执行之后的遗传分析，使用各种区间作图方法。SpA2：首先利用上述表型和氟化物处理方案确定家养和野生型近交系小鼠对氟化物的反应差异。第二，执行芯片映射策略。广泛和长期目标是在动物模型和后来的人类中确定和描述对氟化物敏感的遗传变异，例如多态性。公共卫生意义：本项目的目的是在动物模型中确定氟化物反应的染色体区域。长期目标是在动物模型中确定氟化物反应性遗传变异的特征，确定易受氟化物作用有害影响或潜在不利影响的高危人群，并阐明氟化物影响生物矿化的基本机制。这项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有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.