基于肥胖相关基因Visfatin/PBEF与膝骨关节炎的分子流行病学研究

Some studies have highlighted the complexity and the diversity of genetic contributions to such a multifactorial disease as osteoarthritis. Epidemiological studies have shown that osteoarthritis has a strong genetic component, and a number of candidate genes have been implicated as susceptibility loci for primary osteoarthritis. Understanding ethnicity-speci?c gene effects is just as valuable. The most abundant source of genetic variation in the human genome is represented by single nucleotide polymorphisms(SNPs), which can account for heritable inter-individual differences in complex phenotypes. Obesity represents one of the most important modifiable risk factor for particular peripheral joint sites, predominantly the knee site. Visfatin is a new discovery of another adipokines，regulating the degradation of cartilage matrix in osteoarthritis. Some ?ndings implicated the candidacy of Visfatin/PBEF, an obesity-related genes, as a susceptibility gene for OA development. In the study, we hypothesized that the genetic polymorphisms in Visfatin gene together with environmental factors were associated with OA susceptibility. The objective of this study was to evaluate genetic association of the polymorphism in Visfatin/PBEF with knee osteoarthritis in peripheral joints in a Northeast Chinese population. Unconditional logistic regression analysis was performed to calculate the odd ratios (ORs) with 95% confidence intervals(95%Cls) for estimating the association between certain genotypes and osteoarthritis with adjustment for the possible confounders. Stratified analyse and classification and regression tree model were used to explore potential low-order and high-order gene -environment interactions. We investigated the occurrence of polymorphisms within the Visfatin gene using Taqman probe fluorescent quantitative PCR. The expression level of mRNA and protein expression of Visfatin was further examined. The reporter activities were measured by using dual Dual-Luciferase Reporter Assay System. Identification of SNPs that contribute to susceptibility to such a complex disease will provide highly accurate diagnostic information that will facilitate early diagnosis, prevention, and treatment of osteoarthritis diseases.

骨关节炎的发生和发展是多基因、多因素参与的多阶段过程，且存在明显个体易感性。肥胖与骨关节炎的明确病因关系除了与肥胖引起的软骨破坏的生物力学机制有关外，还与肥胖所致生物代谢异常密切相关。本课题采用以人群为基础的病例对照研究和遗传关联研究方法，调查选定研究人群的环境暴露情况；用ELISA方法测定血清中脂肪因子Visfatin水平；运用BeckMan Genetic Analysis System、Taqman探针荧光定量PCR等技术检测Visfatin基因多态性及基因表达水平，探讨易感SNPs位点之间以及与相关环境因素的交互作用，从环境、基因、临床表型多维度揭示Visfatin与膝骨关节炎发生和进展的关系；采用TASSEL软件构建单倍型块并筛选出其中的htSNP；采用分类回归树方法构建膝骨关节炎发病风险预测模型，为膝骨关节炎发病机制的阐明、个体化危险性评估及预警模型的建立和综合防治提供科学依据

按原计划完成了项目的主要研究内容。本项目根据遗传和环境等诸多因素的影响导致骨关节炎（osteoarthritis, OA）在不同人群中可能存在不同的易感基因，并且多种微效基因在骨关节炎发生和发展中发挥着重要作用，且可能存在基因-基因及基因-环境因素的交互作用的理论基础。流行病学研究发现，肥胖是骨关节炎（无论负重关节，还是非负重关节）发生和发展的独立危险因素，且肥胖人群是成为骨关节炎的高危人群，进而提出肥胖的易感基因也可能是与骨关节炎的候选基因的科学假设。本课题通过分子流行病学研究设计，基于肥胖相关基因Visfatin/PBEF1的多态性及其与环境因素间的交互作用进行骨关节炎的分子流行病学研究，以阐明Visfatin/PBEF1基因与骨关节炎发生和发展的遗传学关联，并进一步探索Visfatin/PBEF1在骨关节炎发生和发展过程中的作用机制。 .在上述方法的基础上，本项目进行了PBEF1基因的遗传多态（SNPs）的检测，分析了不同PBEF1基因tagSNP的基因型单独或联合与膝骨关节炎易感性的关系，探讨不同位点间基因-基因，以及基因-环境暴露（如年龄、肥胖指数BMI）在膝骨关节炎发生发展中的交互作用及其作用方式和强度，从而为膝骨关节炎高危人群的筛检及膝骨关节炎的早期发现提供更有价值的依据，发现了PBEF1基因多个tagSNP标志物与膝骨关节炎发病的相关性。 .另外，在本项目的资助下，我们完成了其他肥胖相关基因的SNPs与膝关节炎关系的研究，如Leptin基因， Resistin基因， Adiponectin基因和FTO基因(fat mass and obesity-associated)与膝骨关节炎关系的关联研究。共发表基金标注的研究论文3篇（其中SCI收录文章1篇，为通讯作者；英文文章1篇，为通讯作者；中文核心期刊发表论文1篇，为通讯作者），另外有与本研究内容密切相关的英文文章2篇待发表，目前均已投稿并且在审稿中。培养硕士研究生1名。