| 摘要: | 第一型胞漿素原活化抑制劑(plasminogen activator inhibitor-1, PAI-1)為體內調控胞漿素原活化劑(plasminogen activator)之主要因子，在體內血栓及纖維蛋白溶解系統的平衡調節中扮演重要的角色。許多疾病狀態下都能發現不正常的PAI-1表現，例如：粥狀動脈硬化、敗血症、腎臟與肺部纖維化等疾病。根據文獻顯示，人類肋膜間皮細胞(human pleural mesothelial cells)與其他發炎細胞大量合成與釋放PAI-1會影響肋膜損傷後的再生修復並促使肋膜纖維化。
本研究利用人類肋膜間皮細胞株MeT-5A探討一種細胞穿透性dynamin抑制劑dynasore對PAI-1蛋白質表現之作用。實驗結果顯示，dynasore能夠分別抑制由TGF-beta1與TNF-alpha所誘導之基質金屬蛋白酵素(matrix metalloproteinase, MMP) MMP-2或MMP-9之酵素活性，且能加強由兩者所誘發之PAI-1蛋白質表現。而單獨投予dynasore，能夠誘導MeT-5A細胞PAI-1蛋白質與mRNA表現，但對於尿激酶型胞漿素原活化劑(urokinase-type plasminogen activator, uPA)之蛋白質與mRNA表現不具影響性，其中dynasore對於PAI-1表現之誘導作用可能與JNK及Smad訊息路徑有關。根據此實驗結果，初步認為dynasore可能藉由PAI-1之表現促進纖維化作用之進行，且對於細胞外基質蛋白分解酵素(extracellular matrix degrading proteases) MMP之活性有抑制性作用。此成分不僅具有成為肋膜黏連劑(pleurodesing agent)之潛力，也可提供肋膜纖維化疾病相關研究一個新的方向，因此往後可進一步探討其詳細分子作用機制，並利用肋膜積液之動物模式探討其促肋膜黏連作用之實際可能性。
Plasminogen activator inhibitor-1 (PAI-1) is a primary regulator of plasminogen activation that plays an essential role in regulating physiological thrombotic/fibrinogic balance. Abnormal expression of PAI-1 has been reported in various types of human diseases, such as atherosclerosis, sepsis, renal and lung fibrosis. PAI-1 produced by human pleural mesothelial cells and other inflammatory cells may have an effect on tissue remodeling and promoting pleural fibrosis.
In this study, we examined the effects of dynasore, a cell-permeable inhibitor of dynamin, on PAI-1 expression and matrix metalloproteinases (MMPs) activation in human pleural mesothelial cell line (MeT-5A). The results indicate that dynasore inhibited the activation of MMP-2 and -9 induced by TGF-beta1 and TNF-alpha respectively. Furthermore, dynasore enhanced the stimulatory effects of TGF-beta1 and TNF-alpha on PAI-1 protein expression. On the other hand, dynasore upregulated PAI-1 expression in MeT-5A cells which may result from JNK and Smad signaling activation. According to the profibrotic effects of dynasore, we suggest that further studies on its molecular mechanisms and in vivo study may be conducted to see its possibility of being a potential pleurodesing agent. |
