METALLOPROTEINASES IN RHEUMATOID ARTHRITIS

类风湿关节炎中高水平的促炎细胞因子引起类风湿关节中基质金属蛋白酶合成增加，导致关节软骨退化和关节功能丧失。转化生长因子β 1 （tgf - β 1）拮抗tnf - α和il -1 β的作用，减少胶原酶1、-2和-2在受这些细胞因子刺激的正常人时细胞中的合成。我们认为该生长因子可能有效减少RA中胶原酶的合成，并将研究其作用机制。具体来说，我们将(a)确定RA滑膜组织和软骨外植体产生的不同胶原酶的水平，并评估tgf - β 1孵育的效果。(2)表征TGFbeta1抑制人时细胞胶原酶-3表达的机制。TGF- β 1对胶原酶-3的抑制作用将在转录或翻译控制方面进行检验，使用正常和永生的人关节时细胞模型，用tnf - α或il -1 β刺激，诱导胶原酶合成的上调。抑制所必需的胶原酶-3启动子的区域/s将通过启动子结构的渐进缺失的瞬时转染来鉴定。我们将进一步定义这些区域与dna酶足迹和电泳位移迁移率测定。(3)表征tgf - β 1诱导胶原酶-3表达的机制。我们将确定低水平的炎症细胞因子是否允许tgf - β 1诱导人关节时细胞中的胶原酶-3。我们将定义与这一现象有关的转录因子。我们假设tgf - β可能是RA组织中所有三种胶原酶的有效调节剂，可能是有用的软骨保护剂，调节胶原酶的合成并影响软骨降解的速度。

The high levels of pro-inflammatory cytokines in rheumatoid arthritis elicit increased synthesis of matrix metalloproteinases in the rheumatoid joint leading to degradation of articular cartilage and loss of joint function. Transforming growth factor beta 1 (TGF-beta1) acts antagonistically to the actions of TNF-alpha and IL-1beta decreasing synthesis of collagenase-1, -2 and -2 in normal human chrondrocytes stimulated with these cytokines. We propose this growth factor may be effective in reducing collagenase synthesis in RA and will study the mechanism of its effects. Specifically we will (a) Determine the levels of different collagenases produced by RA synovial tissue and cartilage explants and evaluate the effects of incubation with TGF-beta1. (2) Characterize the mechanism of TGFbeta1 inhibition of collagenase-3 expression in human chrondrocytes. Inhibition of collagenase-3 by TGF- beta1 will be examined with regard to transcriptional or translational control using a model of normal and immortalized human articular chrondrocytes stimulates with TNF-alpha or IL-1beta to induce up- regulation of collagenase synthesis. The region/s of the collagenase-3 promoter which are necessary for the inhibition will be identified with transient transfections of progressive deletions of the promoter constructs. We will further define these regions with DNase footprinting and electrophoretic shift mobility assays. (3) Characterize the mechanism of TGF-beta1 induction of collagenase-3 expression. We will determine if low levels of inflammatory cytokines are permissive for TGF-beta1 induction of collagenase-3 in human articular chrondrocytes. We will define the transcriptional factors which relate to this phenomena. We postulate that TGF-beta1 would be an effective modulator of all three collagenases in RA tissues and may be useful chondroprotective agent to regulate collagenase synthesis and influence the rate of cartilage degradation.