檳榔素對近端腎小管細胞LLC-PK1在細胞肥大及纖維化之分子機轉探討

據估計全球約有2-6億人口有嚼食檳榔的習慣，普遍存在於中國及東南亞國家，台灣約10% 的人口有嚼食檳榔的習慣。檳榔助於提振精神，其中檳榔鹼為主要因素，而檳榔鹼中尤以arecoline為其主要成分。檳榔除了造成口腔病變之外，也與hepatocellular carcinoma及代謝症候群、動脈粥樣硬化、高血壓、心血管疾病等有相關。因此本研究探討腎臟細胞是否直接受到arecoline的影響並導致病變。結果發現0.25 mM arecoline導致豬近端腎小管上皮細胞LLC-PK1中fibronectin、collagen I、collagen IV及plasminogen activator inhibitor (PAI-1)等蛋白質的表現增加，顯示有細胞纖維化的現象。利用不同的TGF-beta plasmids轉殖進入細胞，發現arecoline能促進其轉錄活性。當合併加入各種訊息傳遞路徑抑制劑發現arecoline透過JNK1/2 pathway活化TGF-beta進而造成fibrosis。Arecoline也藉由活化p21 waf1/cip1而導致細胞肥大。除此之外，arecoline也會活化JNK1/2 pathway而導致COX2表現造成細胞發炎。TGF-?n?畟ル悇﹞鑷eat shock factor 1(HSF1)造成collagen堆積。HSF1為一熱休克轉錄因子，當細胞處於壓力環境時會被誘發出來，本研究發現，HSF1無法逆轉arecoline誘發TGF-?n?珜y成fibrosis的現象，但可透過降低c-Jun及COX2的表現而減緩LLC-PK1細胞發炎的現象。高濃度arecoline會直接誘發細胞走向apoptosis，但其機制尚未明確。綜合以上結果，arecoline 除了透過活化TGF-beta造成腎小管上皮細胞纖維化之外，也會經由JNK1/2調控c-Jun及其下游基因COX2表現而造成發炎反應;而HSF1則可以逆轉arecoline造成LLC-PK1細胞發炎的現象。目前我們正進行以6.11 mg/kg/day arecoline飲用水餵食老鼠，探討其對腎臟的影響。

關鍵字

檳榔素；纖維化；熱休克轉錄因子1

並列摘要

There are over 200-600 million people who has the habit of chewing betal nuts worldwide and the prevalence rate of BQ chewing is about 10% in Taiwan. Betel quid chewing not only leads to oral, pharyngeal and esophageal cancers but also is associated with liver cirrhosis and hepatocellular carcinoma (HCC). Arecoline is the most abundant alkaloid in betel quid and is cytotoxic, genotoxic, mutagenic and tumorigenic to various kinds of cells. Betel nut chewing is also associated with metabolic symdrome, cardiovascular disease and chronic kidney disease. On the other side, heat shock factor 1 (HSF1) protects cells from stresses including anti-inflammatory, anti-oxidant, glucose tolerance and insulin resistant effects. Therefore, the mechanism of how arecoline affects kidney tubular epithelium cells (LLC-PK1) and the role of HSF1 in arecoline-induced effects on LLC-PK1 cells were studied. We found that arecoline inhibited LLC-PK1 cell growth in a dose-dependent and time-dependent manner. Additionally, arecoline induced LLC-PK1 cell hypertrophy. Arecoline also induced LLC-PK1 cell fibrosis by upregulating fibronectin, Collagen IV, Collagen I and plasminogen activator inhibitor- 1 (PAI-1) protein expression. Moreover, decreased of cyclin D1, cyclinE and increased of p21 waf1/cip1 protein expression can be found in arecoline-treated LLC-PK1 cells. We transfected phTH5 (TGF-beta promoter luciferase plasmid) to find out that arecoline activates JNK1/2 to induce TGF-??. We founf that JNK1/2 inhibitor (SP600125) attenuated arecoline-induced fibronectin, Collagen IV, Collagen I and PAI-1 while decreasing c-Jun and cycloxygenase-2 (COX2) expression in arecoline-treated cells. We found that arecoline decreased HSF1 protein expression. Thus, we transfected HSF1 overexpression plasmid to investigate the role of HSF1. We found that HSF1 overexpression attetuated arecoline-induced COX2 expression.

並列關鍵字

arecoline ； renal fibrosis ； heat shock factor 1

參考文獻

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