基于全基因组相关分析的强直性脊椎炎伴发葡萄膜炎遗传发病机制研究

Ankylosing spondylitis (AS)-associated uveitis is one of the most common uveitis entities worldwide. Frequent recurrence of inflammation in patients with AS-associated uveitis leads to severe vision damage in most cases. Genetic background is the critical factor for the development of AS. However, little is known about the precise genetic background for AS-associated uveitis. Our preliminary genome wide association study (GWAS) in 500 AS patients without uveitis, 500 patients with AS-associated uveitis and more than 4000 controls demonstrated a number of genetic polymorphisms which were associated with AS-associated uveitis whereas not associated with AS without uveitis. Most of these gene polymorphisms are located in the following five gene regions: LPS responsive beige-like anchor protein (LRBA), chemokine receptor type 5 (CCR5), Toll-like receptor 1 (TLR1), Leukotriene A4 hydrolase (LTA4H) and complement component 3b/4b receptor 1 (CR1). The proposed project aims: 1) to determine the gene polymorphisms associated with AS-associated uveitis and its clinical phenotypes; 2) to evaluate the common and different genetic background for AS, juvenile idiopathic arthritis-associated uveitis and idiopathic anterior uveitis by examining the AS-associated uveitis-associated gene polymorphisms in more than 1200 patients with AS, more than 500 patients with juvenile idiopathic arthritis-associated uveitis and more than 1300 patients with idiopathic anterior uveitis; 3) to investigate the possible role of AS-associated uveitis-associated gene polymorphisms identified in the development of AS-associated uveitis by computational and functional experiments. This project will expectedly reveal the genetic background for AS-associated uveitis and it’s clinical phenotypes and provide the individual regime for treatment and prognosis evaluation of AS-associated uveitis.

强直性脊椎炎(AS)伴发的葡萄膜炎是最常见前葡萄膜炎类型之一，易反复发作致严重视力损害。遗传在AS的发生中起着重要作用，但AS伴发葡萄膜炎的确切遗传机制尚不清楚。本项目基于我们前期对AS（包括伴发和不伴发葡萄膜炎）全基因组相关分析结果，选择与AS伴发葡萄膜炎相关，而与AS（不发生葡萄膜炎）不相关的LRBA、CCR5、TLR1、LTA4H和CR1等5个基因区，运用目标基因测序等技术及多种分子生物学方法，探讨上述5个基因区多态性与AS伴发葡萄膜炎及其临床表型的相关性；探讨确定与AS伴发葡萄膜炎相关的基因多态是否也与AS（不伴发葡萄膜炎）、幼年型特发性关节炎伴发葡萄膜炎和特发性前葡萄膜炎相关；探讨确定的AS伴发葡萄膜炎相关基因多态参与该病发生的分子生物学机制。该项目实施将可能阐明AS伴发葡萄膜炎及其临床异质性的遗传学基础，为该病个体化诊疗提供理论依据，为该病防治研究提供新的靶点。

强直性脊椎炎(AS)伴发的葡萄膜炎是全球范围内最常见前葡萄膜炎类型之一。本项目利用全基因相关分析的方法，探讨了HLA基因区和非HLA基因区遗传变异与AS及其伴发AAU的相关性。我们基于AAU患者、AS伴发AAU和正常对照者的全基因组相关分析，发现等位基因HLA-B27 (P＜1.0×10-300, OR= 19.66) 、HLA-C基因区SNP rs6919409 (P=6.53×10-131, OR= 54.99)等与AAU（包括AS伴发AAU和特发性AAU）显著相关。将AAU和AS伴发AAU分层分析发现，HLA-B27等位基因与这两组均显著相关。除了在HLA基因区发现了与AS伴发AAU相关的等位基因和SNP之外，还发现了一些与该病显著相关的氨基酸改变。在非HLA基因区发现了600余个多态位点与AS伴发AAU易感性相关（p＜10-4），我们首先选择p值最小的一些单核苷酸多态（SNP）位点，在1000余例AAU患者、1000余例AS伴发AAU和1500余例AS患者中进行验证评估，评价相关多态位点与AS伴发AAU的易感性显著相关，发现了一些与够欧美人群报道相同的遗传变异，也发现了一些与欧美人群不同的遗传变异，目前仍在扩大筛选的遗传变异范围及扩大用于验证的样本量。探讨了遗传变异与AS及其伴发葡萄膜炎、PIU、JIA伴发葡萄膜炎、病毒性前葡萄膜炎、青光眼睫状体综合征等类型葡萄膜炎遗传易感性的相关性，发现不同类型葡萄膜炎存在一些相同的遗传易感基因和不同的遗传易感基因。探讨了表观遗传学参与不同类型葡萄膜炎发生的可能的分子生物学机制，发现Vogt-小柳原田综合征的基因组存在着9个非HLA基因组的显著异常甲基化位点和3个HLA基因区显著异常甲基化位点，其中9个非HLA基因区的低甲基化位点可能导致了这些基因在Vogt-小柳原田综合征患者的异常高表达，进而参与了该病的发生。探讨了相关遗传变异与环境因素等相互作用参与葡萄膜炎发病的生物学机制，发现三个多态位点不同基因型分别与肠道菌群的分布显著相关，而这三个多态位点又与VKH综合征的易感性显著相关。探讨了miRNA与糖尿病视网膜病变发生的相关性及相关生物学机制，发现miRNA参与了糖尿病视网膜病变的发生，抗VEGF治疗可能通过调控miRNA发挥其治疗作用。

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