Department of Anesthesiology, Taipei Medical University Hospital, Taipei, Taiwan.
J Biomed Sci. 2011 Jun 17;18(1):43. doi: 10.1186/1423-0127-18-43.
Osteoarthritis (OA) is a degenerative joint disease which affects the entire joint structure, including the synovial membrane. Disease progression was shown to involve inflammatory changes mediated by proteinase-activated receptor (PAR)-2. Previous studies demonstrated that PAR-2 messenger (m)RNA and protein levels increased in OA synovial cells, suggesting that PAR-2 is a potential therapeutic target of the disease.
We designed a PAR-2-inhibiting peptide (PAR2-IP) by changing an isoleucine residue in the PAR-2-activating peptide (PAR2-AP), SLIGKV, to alanine, generating the SLAGKV peptide. We used it to test PAR-2-mediated inflammatory responses, including the expressions of cyclooxygenase (COX)-2 and matrix metalloproteinase (MMP)-1 and activation of nuclear factor (NF)-κB in human synovial cells. As a control, expressions of COX-2 and MMP-1 were induced by trypsin at both the mRNA and protein levels.
The PAR2-AP increased the expression of COX-2 more dramatically than that of MMP-1. When we treated cells with the designed PAR2-IP, the trypsin-induced COX-2 level was completely inhibited at a moderate concentration of the PAR2-IP. With further examination of trypsin-induced NF-κB activation, we observed sufficient inhibitory effects of the PAR2-IP in synoviosarcoma cells and primary synovial cells from OA patients.
Our study suggests that the PAR2-IP inhibits trypsin-induced NF-κB activation, resulting in a reduction in inflammatory COX-2 expression in synovial cells. Application of PAR2-IP is suggested as a potential therapeutic strategy for OA.
骨关节炎（OA）是一种退行性关节疾病，影响整个关节结构，包括滑膜。疾病进展显示涉及蛋白酶激活受体（PAR）-2 介导的炎症变化。先前的研究表明，OA 滑膜细胞中 PAR-2 信使（m）RNA 和蛋白水平增加，表明 PAR-2 是该疾病的潜在治疗靶点。
我们通过将 PAR-2 激活肽（PAR2-AP）中的异亮氨酸残基改变为丙氨酸，设计了一种 PAR-2 抑制肽（PAR2-IP），生成 SLAGKV 肽。我们使用它来测试 PAR-2 介导的炎症反应，包括人滑膜细胞中环氧化酶（COX）-2 和基质金属蛋白酶（MMP）-1 的表达和核因子（NF）-κB 的激活。作为对照，胰蛋白酶在 mRNA 和蛋白质水平上诱导 COX-2 和 MMP-1 的表达。
PAR2-AP 比 MMP-1 更显著地增加 COX-2 的表达。当我们用设计的 PAR2-IP 处理细胞时，PAR2-IP 在适度浓度下完全抑制了胰蛋白酶诱导的 COX-2 水平。进一步研究胰蛋白酶诱导的 NF-κB 激活，我们观察到 PAR2-IP 在滑膜肉瘤细胞和 OA 患者的原代滑膜细胞中具有足够的抑制作用。
我们的研究表明，PAR2-IP 抑制胰蛋白酶诱导的 NF-κB 激活，导致滑膜细胞中炎症 COX-2 表达减少。PAR2-IP 的应用被建议作为 OA 的潜在治疗策略。
