THBS1/TGFβ/CTGF轴在三氧化二砷调控类风湿关节炎血管增殖中的作用及分子机制

Rheumatoid arthritis (RA) is a common autoimmune disease with high disability rate. Mechanisms involves in RA is still not clear, which lead to a lack of effective therapy. Synovitis and vasculitis are basic pathological features of RA. We discovered the validity of arsenic trioxide (ATO) in RA treatment for the first time, and determined the reduction of vessels in RA mouse models. Experiments in vitro verified that ATO could induce apoptosis of RA synovial fibroblasts through inhibition of NF-κB. Our recent preliminary experiments observed that ATO effectively suppressed THBS1 and TGFβ mediated CTGF secretion. We therefore hypothesized that activation of THBS1/TGFβ/CTGF axis is a novel important mechanism for RA. This project intends to set up animal and cell models of RA, and detects synovium angiogenesis and related indicator expression through activity intervention of THBS1/TGFβ/CTGF axis. A series of methods will be used including gene silencing, flow cytometry, confocal laser scanning microscopy, immunohistochemistry and electron microscopy et al. This investigation intends to reveal the pathogenesis in RA vascular proliferation through signal transduction of THBS1/TGFβ/CTGF axis, and further clarify the possible mechanisms of ATO in anti-angiogenesis therapy. Our research aims to provide significance in seeking new target point for RA treatment and prompting the clinical application of ATO.

类风湿关节炎（RA）是常见自身免疫病，致残率高，确切机制不详，缺少有效疗法。滑膜炎和血管炎是RA的基本病理特征。我们首先发现三氧化二砷（ATO）治疗RA效果好，可减少RA模型鼠滑膜血管数量；体外实验证实ATO可抑制滑膜成纤维细胞（FLS）NF-κB表达和促进凋亡。最近预实验初步观察到，ATO可有效抑制THBS1和TGFβ介导的CTGF分泌。故我们推测THBS1/TGFβ/CTGF轴活化是RA发生的重要机制。为证明该假说，本课题拟复制RA的CIA小鼠模型和FLS细胞模型，采用基因沉默、流式细胞仪、激光共聚焦显微镜、免疫组化、电镜等技术，观察该轴激活和抑制对反映滑膜血管增殖和血管新生指标及相关信号传导通路的影响，阐明ATO对关键信号分子表达和活性的调控作用，进一步明确药物作用靶点和分子机制，为ATO应用于RA的治疗奠定理论基础。

血管增殖是类风湿关节炎（RA）的重要发病机制之一，为滑膜细胞增生及局部炎症反应提供必要条件，进而加剧骨破坏。本课题组在已证实三氧化二砷（As2O3）促进RA滑膜成纤维样细胞（RA-FLS）凋亡，抑制RA模型鼠滑膜血管增殖的基础上，发现As2O3可显著降低血管增殖因子TSP-1和TGF-β介导的CTGF表达水平，因此拟通过研究TSP-1/TGF-β/CTGF轴来发掘As2O3在治疗RA中的作用机制。研究结果显示RA-FLS中TSP-1、TGF-β1、CTGF、VEGF过表达，并相互作用构成轴系乃至微型调控网络，发挥血管增殖模块功能。As2O3可显著抑制RA-FLS及RA模型鼠中TSP-1/TGF-β/CTGF/VEGF轴活化，进而减少滑膜血管增殖数量，有效治疗RA。本课题进行过程中发现As2O3对RA模型鼠脾脏中CD4+T细胞亚群Th17和Treg分布及其功能产生影响，并进一步进行了系统研究。此外，因As2O3可促进自噬进而发挥抗肿瘤的作用，我们大胆设想As2O3可通过促进RA-FLS自噬来治疗RA，进而进行了相关研究，结果显示As2O3可上调RA-FLS受抑的自噬通路，1,25-二羟维生素D （VD）可通过激活上游VD 受体（VDR）基因表达，进而激活下游自噬基因PPARγ表达，从而协同As2O3调控RA-FLS自噬通路，减少As2O3给药剂量及毒性，为As2O3与VD联合应用提供理论依据。