Partridge C A, Jeffrey J J, Malik A B
Department of Physiology, Albany Medical College of Union University, New York 12208.
Am J Physiol. 1993 Nov;265(5 Pt 1):L438-47. doi: 10.1152/ajplung.1993.265.5.L438.
Tumor necrosis factor-alpha (TNF-alpha) may increase vascular endothelial permeability through alteration of the extracellular matrix (ECM). Incubation of bovine pulmonary microvascular endothelial (BPMVE) cells grown to confluence on microporous filters with 10(4) U/ml TNF-alpha for 24 h increased monolayer permeability to 125I-labeled albumin two- to threefold. TNF-alpha treatment also induced expression of a 96-kDa gelatinolytic metalloproteinase that was present in the medium and bound to the ECM. The induced 96-kDa metalloproteinase was purified from conditioned medium and found to cleave fibronectin, laminin, types IV and V collagens, and gelatins from types I and III collagens, suggesting identity as a type IV collagenase-gelatinase. Incubation of BPMVE cells with the 96-kDa gelatinase increased monolayer permeability, an effect prevented by inclusion of either tissue inhibitor of metalloproteinase (TIMP) or 1,10-phenanthroline. When BPMVE cells were incubated with the 96-kDa gelatinase or 10(4) U/ml TNF-alpha and then stripped from the filters, the remaining ECM displayed increased permeability to 125I-albumin compared with matrix from untreated BPMVE. The ECM extracts from both TNF-alpha- and enzyme-treated cells were found to contain less fibronectin, whereas their total protein contents were similar to those of untreated controls. These results suggest that the 96-kDa metalloproteinase induced by TNF-alpha contributes to increased vascular endothelial permeability through the degradation of specific extracellular matrix components.
肿瘤坏死因子-α（TNF-α）可能通过改变细胞外基质（ECM）来增加血管内皮通透性。将在微孔滤膜上生长至汇合的牛肺微血管内皮（BPMVE）细胞与10⁴U/ml TNF-α孵育24小时，可使单层对¹²⁵I标记白蛋白的通透性增加2至3倍。TNF-α处理还诱导了一种96 kDa明胶溶解金属蛋白酶的表达，该酶存在于培养基中并与ECM结合。从条件培养基中纯化出诱导产生的96 kDa金属蛋白酶，发现它能切割纤连蛋白、层粘连蛋白、IV型和V型胶原以及I型和III型胶原的明胶，表明其为IV型胶原酶-明胶酶。用96 kDa明胶酶孵育BPMVE细胞可增加单层通透性，金属蛋白酶组织抑制剂（TIMP）或1,10-菲咯啉的加入可阻止这种作用。当BPMVE细胞与96 kDa明胶酶或10⁴U/ml TNF-α孵育后从滤膜上剥离，与未处理的BPMVE细胞的基质相比，剩余的ECM对¹²⁵I-白蛋白的通透性增加。发现TNF-α和酶处理细胞的ECM提取物中纤连蛋白含量较少，而它们的总蛋白含量与未处理对照相似。这些结果表明，TNF-α诱导的96 kDa金属蛋白酶通过降解特定的细胞外基质成分，促进了血管内皮通透性的增加。
