CD40-CD40L共刺激通路在TAO眶脂肪组织增加中的作用

Thyroid-associated ophthalmopathy ( TAO ) is an autoimmune disease. Its symptoms and signs are mainly due to the excess increase in orbital fat volume, which can lead to protopsis,exposure keratitis, compressive optic neuropathy, visual acuity blur or blindness in TAO patients.Up to now the mechanism of orbital adipose tissue increase in TAO is unclear. Our previous study have shown that CD40-CD40ligand costimulatory pathway induced intercellular adhesion molecule-1(ICMA-1) expression in CD90- orbital fibroblasts and CD90+orbital fibroblasts in patients with TAO,and CD40-CD40ligand costimulatory pathway can lead to fibrosis of extraocular muscle of TAO by regulating interact of CD90+orbital fibroblasts and T lymphocyte.In addition,we succesfully constructed the TAO animal model of BALB/c mice useing vector p-EGFP-C2-hTSHR, charactered with orbital adipose tissue excess increased. On the results above,next we intend to observe the role of CD40-CD40Ligand costimulatory pathway in CD90-OF differentiated into adipocytes and secretion of cell factors and transcription factors of CD90-orbital fibroblasts in TAO patients, and to observe phosphorylation of signal transmission pathways such as MAPK/ERK、Src and NF-κB pathway. By doing this, we want to clarify the role of CD40-CD40L costimulatory pathway in the excess increase of orbital adipose tissue in TAO patients and its related mechanism and to provide new targets for the treatment of orbital adipose increase in TAO patients.

眼眶脂肪组织异常增加可导致甲状腺相关性眼病（TAO）患者眼球突出、暴露性角膜炎、压迫性视神经病变、视力下降甚至失明。目前发病机制不明。我们前期研究明确了CD40-CD40L共刺激通路可介导T淋巴细胞激活眼眶成纤维细胞（OF）(包括CD90- OF和 CD90+OF)表达黏附分子ICAM-1以及激活CD90+OF导致眼外肌纤维化。并用最新质粒pEGFP-C2构建载体pEGFP-C2-hTSHR，成功制备出BALB/c小鼠TAO动物模型。在此基础上，拟采用CD90-OF和TAO动物模型，观察CD40-CD40L共刺激通路对CD90-OF向脂肪细胞转分化及分泌脂肪细胞因子及核转录因子的影响，观察相应的信号传导通路MAPK/ERK、Src、NF-κB的磷酸化，明确 CD40-CD40L共刺激通路在TAO眼眶脂肪组织异常增加中的作用及其机制。为阻断TAO眼眶脂肪组织堆积寻找相应的治疗靶点。

甲状腺相关性眼病（TAO）患者眼眶脂肪组织增加可导致眼球突出、暴露性角膜炎、压迫性视神经病变、视力下降甚至失明。目前发病机制不明。眼眶成纤维细胞（ OF）是TAO自身免疫反应的靶细胞和效应细胞，可分为CD90+OF 与CD90-OF, 其中与CD90-OF主要与眼眶脂肪组织增生有关。CD40-CD40L共刺激通路是一个重要的OF活化通路。本课题采用real-time PCR 及Western-blot等方法进行了CD40-CD40L 共刺激通路与炎症及脂肪相关因子的实验研究，实验结果显示CD40-CD40L 共刺激通路可以调节眼眶成纤维细胞炎症因子IL-6， IL-8，MCP-1、脂肪相关因子PPAR-γ, C/EBPα, 及自身抗原TSHR mRNA的表达，发现CD90+OF表达炎症因子IL-6， IL-8，MCP-1 高于CD90-OF，而脂肪相关因子PPAR-γ, C/EBPα, 及抗原TSHR mRNA 在CD90-OF中表达高于CD90+OF，其中PPAR-γmRAN及蛋白在CD90-OF表达显著增高，而PPAR-γ与TAO眼眶炎症脂肪增殖病理过程密切相关。CD40L以时间和剂量依赖的方式诱导CD90-OF表达PPAR-γmRAN。同时，CD40L可提高CD90-OF向脂肪细胞转分化的转化率。MAPK抑制剂PD98059 、SB203580及NF-KB 抑制剂PDTC减弱PPAR-γmRNA表达，初步明确了CD40-CD40L在TAO眼眶脂肪组织增加的作用及其机制。