海龍鬚菜水層萃取物抑制C 型肝炎病毒複製與抗發炎反應之研究

Aqueous extract of Gracilaria tenuistipitata inhibits Hepatitis C Virus replication and exerts anti-inflammatory effects

陳冠任(Kuan-Jen Chen)

指導教授 ： 李景欽

高雄醫學大學/生命科學院/生物科技學系碩士班/碩士(2011年)

摘要

肝癌死亡率近十年來一直位居台灣癌症死因之第一或第二位。C型肝炎病毒 (Hepatitis C virus; HCV) 感染是造成國人得到肝癌的主要原因之一。感染C型肝炎病毒後，至少有60%以上會轉變為慢性肝炎，接著導致肝硬化甚至肝癌。以目前的干擾素 (IFN-α) 和利巴韋林 (Ribavirin） 的合併使用治療療程對患者並非都有良好的療效，所以繼續開發新穎性的治療藥物有其必要性。根據我們的研究發現，海龍鬚菜水層萃取物 (Aqueous extract of Gracilaria tenuistipitata; AEGT) 具有顯著抑制C型肝炎病毒複製與感染的生物活性，在C型肝炎複製子系統與病毒感染系統的EC50 （抑制50％病毒活性的濃度） 分別約為302與296 μg/ml。除此之外，AEGT可以增強 IFN-α抗C型肝炎病毒複製的效果，未來有潛力開發成合併治療的佐劑。根據文獻指出，細胞感染C型肝炎病毒會導致環氧合酶-2 (Cyclooxygenase-2; COX-2) 基因過度表現，並且與促進病毒複製有關。以C型肝炎複製子系統中，我們證實AEGT是藉由抑制NF-κB-COX-2訊息傳遞路徑達到抑制C型肝炎病毒複製。此外，經由報導基因系統檢測，我們也證實AEGT可抑制病毒NS5A蛋白質所誘發之NF-κB及環氧合酶-2過度表現。利用即時定量聚合酶連鎖反應 (RT-QPCR) 更證實AEGT可降低由NS5A蛋白質與脂多糖(Lipopolysaccharide; LPS) 所刺激之發炎細胞激素分泌，包含Tumor necrosis factor (TNF-α) 、Interleukin-1β (IL-1β) 、Interleukin-6 (IL-6) 、 NO synthase (iNOS) 以及環氧合酶-2。以上結果代表AEGT可能可以成為一個有潛力的抗C型肝炎病毒以及抗發炎反應的藥物或健康食品。

關鍵字

C型肝炎病毒 ； 海龍鬚菜 ； 發炎

並列摘要

Hepatitis C virus (HCV) is one of the most important human pathogens due to frequently lead to chronic hepatitis, liver cirrhosis, and hepatocellular carcinoma (HCC). Current IFN-based therapies are ineffective in many patients infected by HCV, and they are plagued with adverse effects, underscoring the need for new therapeutic strategies. Here we reported that the aqueous extract obtained from Gracilaria tenuistipitata, referred as AEGT, exhibited the inhibition of HCV RNA replication in the HCV replicon system and infectious system, with an EC50 value of 302 and 296 μg/ml, respectively. Besides, the anti-HCV effect can be synergistic when AEGT was combined with IFN-α by a multiple linear logistic model and isobologram analysis. Activation of cyclooxygenase-2 (COX-2) has been implicated in the HCV-associated hepatocellular carcinoma. In our studies, we demonstrated that AEGT significantly inhibited COX-2 expression in HCV replicon cells. In cotrast, the recovery effect of HCV replication was observed in AEGT-treated replicon cells with increased COX-2 protein expression, suggesting that the anti-HCV activity of AEGT was associated with down-regulation of COX-2 gene expression, which was mediated by the suppression of nuclear factor-kappaB (NF-κB) activation. Finally, we also found that AEGT inhibits NS5A-induced and LPS-induced pro-inflammatory mediators including TNF-α, IL-1β, IL-6, iNOS and COX-2 in Huh7 cells and RAW264.7 cells, respectively. These findings provide the possibility that AEGT could be an excellent adjuvant or drug in the treatment of inflammation and chronic HCV infection.

並列關鍵字

HCV ； Gracilaria tenuistipitata ； inflammatory

參考文獻

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