Thalidomide Suppresses Transforming Growth Factor-β1-Induced Fibronectin Expression in Keloid Fibroblasts

蟹足腫是異常增生的疤痕組織，具有大量細胞外基質堆積及異常細胞素活性的特徵。許多證據指出，thalidomide (化學名為N-phthalidomidoglutamide) 含有抗血管新生、抗發炎反應、及免疫調節的特性。過去的研究也發現thalidomide具有抗纖維化的療效，能有效減少細胞外基質的堆積。我們將臨床取得的皮膚檢體進行免疫組織染色，發現蟹足腫檢體相較於正常皮膚檢體表現大量的TGF-β1及fibronectin。將正常及蟹足腫檢體所分離出的纖維母細胞進行體外實驗，發現TGF-β1可誘導fibronectin大量表現，在處理thalidomide的組別中發現其能有效的抑制fibronectin產生。而在實驗中也證實了TGF-β1可以活化MAPKs (ERK1/2、p38及JNK) 和SMADs (Smad2及Smad3) 的磷酸化，但在分別先處理PD98059 (ERK抑制劑) 、SB203580 (p38抑制劑) 及SP600125 (JNK抑制劑) 以及Smad3小片段干擾核酸時，發現皆可抑制纖維母細胞表現fibronectin，代表TGF-β1可透過這些訊息傳遞誘導fibronectin的增加。進一步發現thalidomide能有效的抑制p38及Smad3的磷酸化，對於ERK、JNK及Smad2則沒有影響。除此之外，我們也利用電泳遲滯分析法進行細胞核蛋白之AP-1與Smad3/4活性的探討，發現thalidomide可以有效地降低TGF-β1所誘導的AP-1及Smad3/4與DNA結合的活性。利用明膠酶譜法也發現thalidomide可以增加基質金屬蛋白酶MMP9的活性，進而增加fibronectin的降解，以減少fibronectin的表現量。同時我們建立蟹足腫小鼠模式，發現施打thalidomide的小鼠組別確實可以有效的抑制TGF-β1與fibronectin的表現，也減少了蟹足腫纖維母細胞的數量。綜合以上，thalidomide對於蟹足腫疾病具有抗纖維化的療效，可能是透過抑制TGF-β1活化p38及Smad3磷酸化。我們的研究證實了thalidomide對於治療及預防蟹足腫疾病具有極大的潛力。Keloids are characterized by vigorously continuous production of extracellular matrix protein and aberrant activities of cytokines in the dermis. Growing bodies of evidence indicate that thalidomide, N-phthalidomidoglutamide, has anti-angiogenic, anti-inflammatory, and immunomodulating properties. Thalidomide also possesses the anti-hepato fibrotic effects, due to the reduced TGF-β1 expression. The present study aimed at determining the therapeutic effects of thalidomide on fibronectin expression of transforming growth factor-β (TGF-β)-treated normal and keloid-derived fibroblasts and the underlying mechanism. In surgically removed normal tissue and keloid tissue in human samples, TGF-β1 and fibronectin immunoreactivity was strong in the keloid tissue, but was barely detectable in the normal tissue. TGF-β1 significantly induced fibronectin expression in normal and keloid fibroblasts and the effect was inhibited by pretreatment with thalidomide. TGF-β1 induced MAPKs (ERK1/2, JNK, and p38) and Smad2/3 phosphorylation. Pretreatment with PD98059 (an ERK1/2 inhibitor), SP600125 (a JNK inhibitor), or SB203580 (a p38 inhibitor) inhibited the TGF-β1-induced fibronectin expression. Furthermore, pretreatment with thalidomide effectively inhibited the phosphorylation of p38 and Smad-3, but not JNK , ERK and Smad2 induced by TGF-β1. In addition, thalidomide pretreatment effectively inhibited TGF-β-induced AP-1 and Smad3/4 DNA binding activity by electrophoretic mobility shift assay. Moreover, thalidomide treatment caused fibronectin degradation through increasing the activity of matrix metalloproteinase 9 by gelatin zymography. We also found that treatment with thalidomide significantly suppressed the production of TGF-β1 and fibronectin as well as the cell number in the in vivo keloid model. These results suggested that thalidomide exerted antifibrotic effect on keloid and the effect may be mediated by the suppression of the TGF-β-induced p38 and Smad3 signaling. Our findings indicated that thalidomide may be a potential drug candidate for the treatment and prevention of keloids