摘要
目的通过研究脂蛋白a对巨噬细胞源性基质金属蛋白酶(MMPs)和基质金属蛋白酶内源性组织拟制剂(TIMPs)表达的调节作用,探讨脂蛋白a促动脉粥样硬化的机制。方法利用从新鲜混合血浆经超速离心和亲和层析纯化的脂蛋白a刺激人单核细胞白血病THP_1细胞经豆蔻酰佛波醇乙酯诱导24 h转化而成的巨噬细胞,孵育10 h和36 h后收集细胞裂解液和条件培养基分别进行MMPs/TIMPs mRNA和蛋白检测及明胶酶谱分析MMPs活性。结果免疫印迹结果显示脂蛋白a可使巨噬细胞培养基中MMP_1、MMP_2、MMP_9、MT1_MMP水平明显上调,其中MMP_2和MT1_MMP的活性形式明显增加;而其抑制剂TIMP_1、TIMP_2水平则明显减少,以前者的剂量效应最为明显。明胶酶谱分析表明条件培养基中MMP_9活性增强。逆转录聚合酶链式反应结果显示,MMP_1、MMP_2、MMP_9 mRNA水平随Lp(a)刺激增强而增加,TIMP_1 mRNA水平则梯度降低,而MT1_MMP、TIMP_2的mRNA水平未见明显改变。结论研究发现Lp(a)可促进巨噬细胞表达多种MMPs,同时抑制TIMPs的表达,由此所致的MMPs/TIMPs表达及活性失衡最终可致基质过度降解,在整体情况下则可能促进斑块进展成不稳定斑块并破裂。为阐明Lp(a)的促动脉粥样硬化机制提供了新的线索。
Objective Maerophage-derived matrix metalloproteinases （MMPs） and endogenous tissue inhibitors of matrix metalloproteinase （TIMPs） play a central role in atherosclerotic plaque enlargement and its ultimate rupture. Lipoprotein（a） [ Lp （a）] deposits in macrophage-rich plaques are correlated with acute coronary syndrome. We hypothesized that Lp（a） might regulate the expression of MMPs and ＇liMPs in macrophages. Methods Macrophages were obtained by transforming THP-1 cell line with phorbol 12-myristate 13-acetate （PMA）. The THP-1-derived macrophages were exposed to Lp（a） （5 - 20 μg/mL） for 36 hours, and the production of MMP-1, MMP-2, MMP-9 and membrane type 1-MMP （MT1-MMP）, and the expression of TIMP-1 and TIMP-2 were assayed by Western blot and gelatin zymography. Results The exposure of THP-1-derived macrophages to Lp （a） （5 - 20 μg/mL） for 36 hours increased the production of MMP-1, MMP-2, MMP-9, and membrane type 1-MMP, and suppressed the expression of TIMP-1 along with the changes of Lp（a） dosage, as indicated by Western blot and gelatin zymography. Reverse transcription-polymerase chain reaction （RT-PCR） revealed that alterations in protein production of MMP-1, MMP-2, MMP-9 and TIMP-1 mainly resulted from changes of mRNA transcription. Conclusions Lp（a） induces abnormal expression/activity of MMPs and TIMPs in THP-1 macrophages. The present study put forward the possibility that Lp（a） might contribute to plaque vulnerability and consequent rupture in atherosclerosis.
出处
《中国比较医学杂志》
CAS
2006年第12期710-715,共6页
Chinese Journal of Comparative Medicine
基金
科技部国家重大基础项目(973)(2006CB503805)
科技部公益基金项目(2004DIA1J001)
