吡咯烷二硫代氨基甲酸盐下调基质金属蛋白酶9表达机制的研究

Study on the mechanism of pyrrolidine dithiocarbamate down-regulating matrix metalloproteinase-9 expression

目的探讨TNF-α诱导的肺泡巨噬细胞(AM)性基质金属蛋白酶9(MMP-9)表达的信号通路以及吡咯烷二硫代氨基甲酸盐(PDTC)对MMP-9表达的影响机制。方法从慢性阻塞性肺疾病患者支气管肺泡灌洗液中分离与培养AM,以PDTC预处理AM,以TNF-α或IL-1刺激AM。半定量逆转录-聚合酶链反应法检测MMP-9 mRNA的表达;Western blot检测MMP-9蛋白的表达及TNF-α或IL-1诱导的IκBα磷酸化水平。凝胶阻滞分析实验检测NF-κB活性。结果TNF-α上调AM源性MMP-9 mRNA和蛋白的表达(P<0.05);PDTC抑制TNF-α诱导的MMP-9的表达(P<0.05)。PDTC对TNF-α或IL-1诱导的IκBα的磷酸化均无抑制作用(P>0.05)。PDTC对TNF-α或IL-1诱导的NF-κB的活化均有抑制作用(P<0.05);且PDTC不能在体外直接抑制NF-κB的DNA结合活性(P>0.05)。结论NF-κB在TNF-α诱导的AM源性MMP-9的表达中起着重要作用;PDTC可能通过抑制泛素化-蛋白酶小体途径来下调TNF-α诱导的AM源性MMP-9的表达。

Aim To study the effects of pyrrolidine di- thiocarbamate （ PDTC ） on matrix metalloproteinase-9 （ MMP-9 ） expression in alveolar macrophages （ AM ） induced by TNF-α, and then to explore it＇s signal pathway. Methods AM were collected from bronchoalveolar lavage fluid in patients with chronic obstructive pulmonary disease. AM were pretreated with PDTC and then stimulated by TNF-α or IL-1. MMP-9 mRNA expression was detected by semi-quantitative re- verse transcription-polymerasc chain reaction and MMP-9 protein expression was detected by Western blot. Phospho-IKBα protein levels induced by TNF-α or IL-1 were detected by Western blot. NF-KB activity was detected by electrophoretic mobility shift assay. Results Both the mRNA and protein levels of MMP-9 induced by TNF-α in AM were significantly elevated in a dose dependent manner （ P 〈 0. 05 ）. The expression of MMP-9 induced by TNF-α was significantly inhibi- ted by PDTC （P 〈 0. 05 ）. PDTC had no clear effect of inhibiting the phosphorylation of IKBα induced by TNF-α or IL-1 （P 〉 0.05 ）. PDTC had distinct effect of inhibiting the activation of NF-KB induced by TNF-cα or IL-1 in a dose-dependent manner（P 〈0.05）. It al- so showed PDTC couldn＇t directly inhibit NF-KB DNA binding activity in vitro （ P 〉 0. 05 ）. Conclusions NF-KB plays an important role in MMP-9 expression induced by TNF-α in AM; PDTC can down-regulate MMP-9 expression induced by TNF-α in AM possibly through preventing the degradation of IKBα via ubiquitylation-proteasome proteolytic pathway.