Surfactant protein A increases matrix metalloproteinase-9 production by THP-1 cells
Surfactant protein A increases matrix metalloproteinase-9 production by THP-1 cells
复制标题
DOI：
10.1152/ajplung.00082.2003
复制
发表时间：
2003-10-01
影响因子：
4.9
通讯作者：
Phelps, DS
中科院分区：
文献类型：
--
作者：
de Lara, LGV;Umstead, TM;Phelps, DS
来自肺泡巨噬细胞的基质金属蛋白酶（MMP）-9是肺中弹性蛋白溶解活性的主要来源。在肺气肿患者的支气管肺泡灌洗液中增加。虽然巨噬细胞衍生的弹性蛋白溶解活性在肺气肿发病机制中的重要性已得到充分证实，但关于MMP-9的调节和活性仍存在问题。由于表面活性蛋白A（SP-A）能够调节人单核细胞的其他功能，我们假设SP-A可能调节MMP-9的表达。维生素D-3分化的THP-1细胞和外周血单个核细胞在体外用几种浓度的SP-A刺激不同的孵育时间。MMP-9 mRNA表达通过斑点印迹分析测定，明胶酶谱法测定培养基中的明胶分解活性，ELISA测定蛋白质表达，并使用特异性MMP-9活性测定来测量细胞上清液中该酶的活化状态。SP-A可诱导两种细胞MMP-9的表达，其作用呈时间和剂量依赖性，且MMP-9以酶原形式释放。根据中和抗体研究的结果，我们认为SP-A的作用是通过Toll样受体2介导的。尽管这些发现的生物学意义仍有待阐明，但这些观察结果表明存在一种新的局部控制机制，MMP-9水平可能在肺泡巨噬细胞中受到调节。我们推测，SP-A可能会影响蛋白酶/抗蛋白酶的平衡，在患者的肺表面活性剂成分的定量和/或定性变化，有利于细胞外基质成分的异常分解。
Matrix metalloproteinase (MMP)-9 from alveolar macrophages is a major source of elastolytic activity in the lung. It is increased in the bronchoalveolar lavage fluid of patients with emphysema. Although the importance of macrophage-derived elastolytic activity in the pathogenesis of emphysema is well established, questions remain about MMP-9 regulation and activity. Because surfactant protein A (SP-A) is capable of modulating other functions of human monocytic cells, we hypothesized that SP-A may regulate MMP-9 expression. Vitamin D-3-differentiated THP-1 cells and peripheral blood mononuclear cells were stimulated in vitro with several concentrations of SP-A for different incubation times. MMP-9 mRNA expression was measured by dot-blot analysis, gelatinolytic activity in the medium was determined by gel zymography, protein expression was determined by ELISA, and a specific MMP-9 activity assay was used to measure the state of activation of this enzyme in the cell supernatants. SP-A induced the expression of MMP-9 in both cell types, the effect was time and dose dependent, and MMP-9 was released in its zymogen form. On the basis of results of neutralizing antibody studies, we believe that SP-A action is mediated through Toll-like receptor-2. Even though the biological meaning of these findings remains to be elucidated, these observations suggest the presence of a novel, locally controlled mechanism by which MMP-9 levels may be regulated in alveolar macrophages. We speculate that SP-A may influence the protease/antiprotease balance in the lungs of patients with quantitative and/or qualitative changes in surfactant constituents favoring an abnormal breakdown of extracellular matrix components.