Arner E C, Tortorella M D
Du Pont Merck Pharmaceutical Company, Wilmington, DE 19880-0400, USA.
Arthritis Rheum. 1995 Sep;38(9):1304-14. doi: 10.1002/art.1780380919.
To study the role of signal transduction via integrin receptors in the production of metalloproteinase by rabbit articular chondrocytes.
Confluent, primary rabbit articular chondrocytes (RAC) were incubated for 72 hours in the presence of interleukin-1 (IL-1), Arg-Gly-Asp (RGD) peptide, or a combination of IL-1 and RGD peptide. Media were analyzed for stromelysin enzymatic activity using a 3H-labeled transferrin substrate, and for stromelysin and collagenase protein by Western analysis. Gelatinase activity was analyzed by gelatin zymography. IL-1 receptor antagonist (IL-1Ra) protein was used to determine the involvement of IL-1 in mediating the effects of RGD peptide, and fluorescence-activated cell sorter analysis (FACS) was used to examine the effect of IL-1 on chondrocyte integrin subunit expression.
RGD peptides induced chondrocyte synthesis of stromelysin, collagenase, and 92-kd gelatinase B, and increased synthesis of the constitutively expressed 72-kd gelatinase A. Further studies focusing on stromelysin demonstrated that this up-regulation was concentration dependent and that RGD peptides synergized with IL-1 in inducing stromelysin synthesis. RGD-induced stromelysin production was inhibited by the IL-1Ra in a concentration-dependent manner, indicating that induction by RGD requires binding of IL-1 to its receptor. FACS analysis of RAC showed that IL-1 stimulation increased the expression of beta 1 and alpha v integrin subunits on the chondrocyte surface.
Our data demonstrate that signal transduction through chondrocyte integrin receptors up-regulates metalloproteinase expression and that this is likely mediated through induction of IL-1. They also suggest that the binding of adhesion molecules to their chondrocyte integrin receptors reduces the amount of IL-1 required to induce stromelysin synthesis. Up-regulation of chondrocyte integrin expression by IL-1 may play a role in the synergistic effects seen with a combination of IL-1 and RGD peptides. Since elevated levels of both IL-1 and adhesion molecules are present in rheumatoid arthritis and osteoarthritis synovial fluid, our data suggest that this interaction may be important in mediating the cartilage destruction accompanying these diseases.
研究整合素受体信号转导在兔关节软骨细胞金属蛋白酶产生中的作用。
将汇合的原代兔关节软骨细胞（RAC）在白细胞介素 -1（IL -1）、精氨酸 - 甘氨酸 - 天冬氨酸（RGD）肽或IL -1与RGD肽组合存在的情况下孵育72小时。使用3H标记的转铁蛋白底物分析培养基中的基质溶解素酶活性，通过蛋白质免疫印迹法分析基质溶解素和胶原酶蛋白。通过明胶酶谱法分析明胶酶活性。使用IL -1受体拮抗剂（IL -1Ra）蛋白来确定IL -1在介导RGD肽作用中的参与情况，并使用荧光激活细胞分选分析（FACS）来检测IL -1对软骨细胞整合素亚基表达的影响。
RGD肽诱导软骨细胞合成基质溶解素、胶原酶和92-kd明胶酶B，并增加组成性表达的72-kd明胶酶A的合成。对基质溶解素的进一步研究表明，这种上调是浓度依赖性的，并且RGD肽与IL -1协同诱导基质溶解素合成。RGD诱导的基质溶解素产生被IL -1Ra以浓度依赖性方式抑制，表明RGD的诱导需要IL -1与其受体结合。对RAC的FACS分析表明，IL -1刺激增加了软骨细胞表面β1和αv整合素亚基的表达。
我们的数据表明，通过软骨细胞整合素受体的信号转导上调金属蛋白酶表达，这可能是通过诱导IL -1介导的。它们还表明，粘附分子与其软骨细胞整合素受体的结合减少了诱导基质溶解素合成所需的IL -1量。IL -1对软骨细胞整合素表达的上调可能在IL -1与RGD肽组合所见的协同效应中起作用。由于类风湿性关节炎和骨关节炎滑液中同时存在高水平的IL -1和粘附分子，我们的数据表明这种相互作用可能在介导这些疾病伴随的软骨破坏中起重要作用。
