Age-Related Macular Degeneration: Genetic Variations and Animal Model

年龄相关性黄斑变性（AMD）在老年人中引起不可逆的中央视力丧失。各种研究表明AMD有显著的遗传成分。目前的证据支持基因变异导致疾病易感性的假设。2003年，我们启动了这个项目，招募了晚期AMD患者和年龄匹配的正常视网膜对照个体。迄今为止，已有449人被纳入研究，并收集了107例AMD的组织病理学病例。我们继续分析来自澳大利亚蓝山眼研究的835份DNA样本和来自美国历史AREDS的534份DNA样本。我们比较了AMD和对照组之间候选基因内单核苷酸多态性（snp）的等位基因频率，并通过体外和/或体内实验对这些snp进行了功能研究。通过这种方法，我们已经确定了AMD的遗传危险因素以及这些基因变异在疾病发病机制中的可能作用。基于从上述方法获得的信息，已经产生了一种基因工程动物作为AMD模型。2011财年，(1)我们与另外3家校外研究机构签订了材料转移协议，并将ccl2/cx3cr1缺乏症的活小鼠送到他们那里研究AMD的机制和治疗方案；(2)利用已有的平台，完成了8个基因拷贝数变异与AMD关联的研究。该结果已发表在IOVS；(3)我们继续对AMD小鼠模型ccl2/cx3cr1缺陷小鼠进行超微结构表征。我们发现这些小鼠视网膜病变的突触和组织因子表达发生了病理改变。我们在ARVO 2011上报道了突触数据，并全文发表了组织因子的结果；(4)我们通过靶向小胶质细胞来评估纳洛酮对病变的抑制作用，评估AAV-sFLT01基因在ccl2/cx3cr1缺陷小鼠中的治疗效果，并将结果发表在两篇文章（Shen, IOVS and two, Neurobiol Aging）。目前，我们正在利用这种动物模型测试其他化合物如PDGF-CC和PEDF的作用。在与Prockop博士的合作中，我们测试了TSG-6（一种来自间充质干细胞的分泌蛋白）对ccl2/cx3cr1缺陷小鼠视网膜病变的影响，并在ARVO 2011上报道；(5)我们对抗vegf治疗AMD的疗效与患者基因型的关系进行了药物基因组学研究，结果发表在ARVO 2011上；(6)为合作者提供基因组材料，用于AMD的表观遗传和免疫学参与研究，以及全基因组关联研究的验证；(7)发表特邀评论论文3篇，编写专著2章。

Age-related macular degeneration (AMD) causes irreversible central visual loss in the aged population. Various studies suggest that AMD has a significant genetic component. Current evidence supports the hypothesis that gene variation places a predisposition to the disease. In 2003, we initiated this project by recruiting advanced AMD patients and age-matched control individuals with normal retinas. Up to date, 449 individuals have been enrolled and 107 histopathological cases with AMD have been collected. We continue analyzing 835 DNA samples from the Blue Mountain Eye Study in Australia and 534 DNA samples from a historical AREDS in USA. We are comparing the allelic frequencies of single nucleotide polymorphisms (SNPs) within candidate genes between AMD and control subjects followed by the functional studies of these SNPs by in vitro and/or in vivo experiments. Through this approach, we have identified genetic risk factors of AMD and the possible roles of these gene variations in the pathogenesis of the disease. Based on the information obtained from the above approaches, a genetically engineered animal has been generated to act as the AMD model. In FY2011, (1) We created material transfer agreements with 3 additional extramural research institutes and sent them living mice (ccl2/cx3cr1 deficiency) to study mechanism and therapeutic options for AMD; (2) Using previous established platforms, we completed the study on copy number variation of 8 genes and AMD association. The result has been published in IOVS; (3) We continued characterizing ccl2/cx3cr1 deficient mice, a murine model of AMD, in ultrastructure. We found pathological changes in synapse and tissue factor expression on the retinal lesions of these mice. We reported the synapse data in ARVO 2011 and published the result of tissue factor in full article; (4) We evaluated the suppressive effect of naloxone on the lesions by targeting microglia and evaluated AAV-sFLT01 gene therapy in the ccl2/cx3cr1 deficient mice and published the results in two articles (Shen, IOVS and Tuo, Neurobiol Aging). Currently, we are testing the effects of other compounds such as PDGF-CC and PEDF by using this animal model. In a collaboration with Dr. Prockop, we tested the effect of TSG-6, a secreted protein from the mesenchymal stem cells on the retinal lesion of ccl2/cx3cr1 deficient mice and reported in ARVO 2011; (5) We conducted a pharmacogenomic study on the relationship between the efficacy of anti-VEGF therapy on AMD and patients genotypes and results were presented in ARVO 2011; (6) We provided the genomic material to collaborators for studies on epigenetic and immunological involvements in AMD, and verification of Genome-Wide Association Study; (7) Three invited review papers were published and two book chapters were prepared.