Department of Neurosurgery, Department of Emergency and Critical Care Medicine, Taipei Medical University-Shuang Ho Hospital, Taipei, Taiwan, Republic of China.
J Biomed Sci. 2009 Oct 23;16(1):97. doi: 10.1186/1423-0127-16-97.
To investigate the mechanism how Transforming growth factor-beta(TGF-beta) represses Interleukin-1beta (IL-1beta)-induced Proteinase-Activated Receptor-2 (PAR-2) expression in human primary synovial cells (hPSCs). Human chondrocytes and hPSCs isolated from cartilages and synovium of Osteoarthritis (OA) patients were cultured with 10% fetal bovine serum media or serum free media before treatment with IL-1beta, TGF-beta1, or Connective tissue growth factor (CTGF). The expression of PAR-2 was detected using reverse transcriptase-polymerase chain reaction (RT-PCR) and western blotting. Collagen zymography was performed to assess the activity of Matrix metalloproteinases-13 (MMP-13). It was demonstrated that IL-1beta induces PAR-2 expression via p38 pathway in hPSCs. This induction can be repressed by TGF-beta and was observed to persist for at least 48 hrs, suggesting that TGF-beta inhibits PAR-2 expression through multiple pathways. First of all, TGF-beta was able to inhibit PAR-2 activity by inhibiting IL-1beta-induced p38 signal transduction and secondly the inhibition was also indirectly due to MMP-13 inactivation. Finally, TGF-beta was able to induce CTGF, and in turn CTGF represses PAR-2 expression by inhibiting IL-1beta-induced phospho-p38 level. TGF-beta could prevent OA from progression with the anabolic ability to induce CTGF production to maintain extracellular matrix (ECM) integrity and to down regulate PAR-2 expression, and the anti-catabolic ability to induce Tissue inhibitors of metalloproteinase-3 (TIMP-3) production to inhibit MMPs leading to avoid PAR-2 over-expression. Because IL-1beta-induced PAR-2 expressed in hPSCs might play a significantly important role in early phase of OA, PAR-2 repression by exogenous TGF-beta or other agents might be an ideal therapeutic target to prevent OA from progression.
为了研究转化生长因子-β（TGF-β）如何抑制人原代滑膜细胞（hPSCs）中白细胞介素-1β（IL-1β）诱导的蛋白酶激活受体-2（PAR-2）的表达，我们分离培养了骨关节炎（OA）患者软骨和滑膜来源的人软骨细胞和 hPSCs，用含 10%胎牛血清的培养基或无血清培养基培养，然后用 IL-1β、TGF-β1 或结缔组织生长因子（CTGF）处理。采用逆转录-聚合酶链反应（RT-PCR）和 Western blot 检测 PAR-2 的表达。采用胶原酶谱法评估基质金属蛋白酶-13（MMP-13）的活性。结果表明，IL-1β通过 hPSCs 中的 p38 途径诱导 PAR-2 的表达。这种诱导可以被 TGF-β抑制，并观察到至少持续 48 小时，表明 TGF-β 通过多种途径抑制 PAR-2 的表达。首先，TGF-β能够通过抑制 IL-1β诱导的 p38 信号转导来抑制 PAR-2 的活性，其次这种抑制也是间接的，因为 MMP-13 的失活。最后，TGF-β能够诱导 CTGF，进而通过抑制 IL-1β诱导的磷酸化 p38 水平来抑制 PAR-2 的表达。TGF-β通过诱导 CTGF 的产生来预防 OA 的进展，具有合成代谢能力，以维持细胞外基质（ECM）的完整性并下调 PAR-2 的表达，同时具有抗分解代谢能力，诱导组织金属蛋白酶抑制剂-3（TIMP-3）的产生以抑制 MMPs，从而避免 PAR-2 的过度表达。因为在 hPSCs 中由 IL-1β诱导的 PAR-2 的表达可能在 OA 的早期阶段发挥重要作用，所以外源性 TGF-β或其他药物抑制 PAR-2 的表达可能是预防 OA 进展的理想治疗靶点。
