EGCG 經抑制JNK及Smad3影響尼古丁誘導人類牙齦纖維母細胞的CTGF 表現

Abstract

許多有關抽菸引起的健康問題如今已經是非常顯而易見，而且其中許多已被研究證實，例如抽菸和許多器官的癌症、心血管疾病、呼吸系統疾病有關，也會減低生殖能力。抽菸也會對口腔組織有不良的影響，是造成口腔癌、許多口腔黏膜病灶，及牙周病的危險因子。此外，也有文獻指出抽菸合併檳榔的使用和口腔黏膜纖維化及口腔癌有關。在臨床上，我們也常常觀察到抽菸的病人的牙齦會有明顯纖維化的情形。Takeuchi等人(2010)最近的研究指出Nicotine會使人類牙齦纖維母細胞的Type I collagen表現量增加，也會誘發人類牙齦纖維母細胞表現CTGF 。 Nicotine-induced CTGF expression可能是抽菸引起的牙齦纖維化的重要機制。 但是尼古丁誘導CTGF表現之訊息傳遞路徑目前並不清楚，且CTGF的表現可能會因組織不同，而有不同的訊息傳遞路徑和調節機制。 本研究以各種不同訊息傳導路徑的抑制劑前處理人類牙齦纖維母細胞，發現Nicotine可能透過JNK、Rac-1、Smad3、ALK5、ROS、Rho等pathways誘發人類牙齦纖維母細胞表現CTGF protein，我們也發現在MAPKs： ERK、JNK、 p38 MAPK 此三成員之中則僅有JNK參與Nicotine誘導CTGF protein的合成路徑。此外，我們也發現Nicotine會誘發Smad3及JNK蛋白質的磷酸化。其中ALK5 抑制劑可以抑制Nicotine誘導CTGF protein的合成，Nicotine會誘發Smad3蛋白質的磷酸化，可見得Nicotine 會 trans-activate TGF-β訊息傳導路徑，為前所未有的發現，有待進一步之研究。此外，本研究發現EGCG可以藉抑制JNK及Smad3的磷酸化來抑制人類牙齦纖維母細胞表現CTGF protein。Lovastatin可以藉抑制JNK的磷酸化來抑制人類牙齦纖維母細胞表現CTGF protein。

Smoking causes many complications throughout the body and virtually harms every organ. Smoking is responsible for cancer in multiple organs, cardiovascular diseases, respiratory diseases, reproductive effects and many other diseases. Smoking is also an strong risk factor for oral cancer, and periodontitis and smoking combined with betel nut chewing is associated with oral fibrosis and cancer. The typical clinical appearance of the smoker’s gingival tissue demonstrates relatively low levels of marginal inflammation and a tendency to a more fibrotic appearance with little edema. A recent in vitro study used fibroblasts isolated from human gingivae and periodontal liamant and showed that nicotine could elevate productionof type I collagen and CTGF expression (Takeuchi et al. 2010). Induction of CTGF by nicotine might be a major promoter of gingival fibrosis cause by smoking, but the mechanism is unknown. In this study, we found that nicotine might stimulate human gingival fibroblasts to express CTGF through JNK、Rac-1、Smad3、ALK5、ROS、Rho pathways. Nicotine could induce phosphorylation of JNK and Smad3 protein. This is the first report to describe nicotine might trans-activate TGF-β expression since nicotine could CTGF expression was suppressed by SB431542(ALK5 inhibitor) and nicotine could induce phosphorylation of Smad3 protein, We also showed that EGCG might suppress nicotine-induced CTGF expression through JNK and Smad3 pathways and lovastatin did through JNK pathway.