ERAP1多态性影响HLA-B27多聚体的合成致强直性脊柱炎发病的机制研究

Ankylosing spondylitis (AS) is a common autoimmune disease with the significant genetic correlation and high morbidity and rate of disability, and its pathogenesis is still not clear. HLA-B27 β2m-free heavy chains (FHCs) is formed by HLA-B27 misfolded, it can be recognized by CD4 + T cells and other cell surface receptor, causing abnormal body immune response.ERAP1 is a non MHC susceptibility gene with the most close relationship with AS.ERAP1 can cut and modify the antigen peptides in the immune response, and make them to be suitable length.Our previous study found several ERAP1 SNPs closely related to AS .They can affect the function of ERAP1, resulting in that it can’t cut and modify the antigen peptides to be suitable length to supply to HLA-B27 to load,and then HLA-B27 misfolded.But whether ERAP1 SNPs of AS patients lead to the synthesis of FHC,and whether FHC synthesis is the key pathogenesis of AS remains to be proved.The project aims to use flow cytometry detection, co-culture and other techniques to verify the above theory through analysis and experiment of clinical samples, cell experiment, in vivo experiment.The result of this study will contribute to: explain the pathogenesis of AS around the abnormal in the antigen-presenting process in the immune response, and also provide a new target for drug research and development of AS at the same time.

强直性脊柱炎（AS)是遗传因素占主导的自身免疫性疾病，发病人数多、致残率高，发病机制不明确。HLA-B27游离重链多聚体（FHC）是由HLA-B27错构折叠形成的，它可以被CD4+T细胞等多种细胞表面的特异性受体所识别，从而引起机体异常的免疫反应。内质网氨肽酶1（ERAP1）是与AS关联密切的非MHC类易感基因，在内质网中负责将抗原肽剪切成合适的长度。我们的前期研究发现了ERAP1的几个可影响其自身功能的SNPs，它们使抗原肽不能被剪切供HLA-B27装载，以致HLA-B27错构折叠。但AS患者体内ERAP1的SNPs是否导致FHC合成，以及FHC形成是否就是AS发病的关键，还有待证明。本项目拟采用流式细胞术、共培养等技术，通过临床样本分析实验、细胞实验、体内实验等验证上述理论。本研究结果有助于：围绕免疫反应中抗原递呈环节异常解释AS发病机制，同时也为AS药物研发提供新靶点。

强直性脊柱炎（AS）是遗传因素占主导的自身免疫性疾病，发病人数多、致残率高，发病机制不明确。经调查，我国AS患病率在0.3%左右，AS患者群体数量庞大。AS好发于中青年，早期以炎症为主，到晚期可出现病理性新骨形成，最终因脊柱或外周关节融合导致患者丧失运动功能和生活能力，给患者家庭和社会带来沉重的负担。HLA-B27多聚体（FHC）是由HLA-B27错构折叠形成的，它可以被CD4+T细胞等多种细胞表面的特异性受体所识别，从而引起机体异常的免疫反应。内质网氨肽酶1（ERAP1）是与AS关联密切的非MHC类易感基因，在内质网中负责将抗原肽剪切成合适的长度。我们的前期研究发现了ERAP1的几个可影响其自身功能的SNPs，它们使抗原肽不能被剪切供HLA-B27装载，以致HLA-B27错构折叠，进而引起一系列免疫反应。但AS患者体内ERAP1的SNPs是否导致骨化形成，某些SNP是否就是AS发病的关键，还有待证明。本项目采用各种生物学技术，通过临床样本分析实验、细胞实验、体内实验等验证上述理论。发现ERAP1的rs30187的位点多态性会导致AS患者巨噬细胞VEGF高表达，进而诱导间充质干细胞成骨分化。并由此得出上述SNP的AS患者更易早期发生骨化的风险。通过动物实验，我们应用VEGFR1可溶性受体抑制剂在AS动物模型脊柱局部进行注射后发现，可以大大缓解AS小鼠疾病进展。本研究结果有助于：围绕ERAP1的SNP与AS异常病理表型联系起来，并深入挖掘相关机制，同时也为AS早期诊断，风险预测、临床早期干预和药物研发提供新靶点。