Collagenase-1, stromelysin-1 and 92 kDa gelatinase are associated with tumor necrosis factor-alpha induced morphological change of human endothelial cells in vitro.

Recently, we have shown that the tumor necrosis factor-alpha (TNF-alpha)-induced morphological change of EA.hy 926 human endothelial cells is associated with a decrease in the net synthesis of two proteoglycans (PGs), biglycan and syndecan-1, both of which have been suggested to play a role in cell adhesion. Here we have examined whether this phenotypic modulation of EA.hy 926 cells also involves altered expression of matrix metalloproteinases (MMPs) or their tissue inhibitors (TIMPs). We demonstrate that, when forming cobblestone-like monolayer cultures, these cells express and synthesize collagenase-1 (MMP-1), stromelysin-1 (MMP-3) and 72 kDa (MMP-2) and 92 kDa (MMP-9) gelatinases, all of which have previously been found in either normal or pathological human vascular wall. EA.hy 926 cells also express membrane-typel MMP (MT1-MMP), but not matrilysin (MMP-7) and collagenase-3 (MMP-13). As regards TIMPs, we show that these cells express TIMP-1 and TIMP-2, but not TIMP-3 or TIMP-4. Exposure of the cells to TNF-alpha changed the cell morphology from a polygonal shape into a spindle shape and also increased the mRNA levels of MMP-1, MMP-3 and MMP-9, but slightly decreased the MMP-2 mRNA level. No change at the mRNA level of MT1-MMP was observed. Similarly to unstimulated cultures, no mRNA for MMP-7 or MMP-13 was detected in the TNF-alpha treated cultures. TNF-alpha had no effect on the TIMP-1 and TIMP-2 mRNA levels and did not induce TIMP-3 or TIMP-4 expression. Gelatin zymography and Western blot analysis revealed that the increase observed at the mRNA level of MMP-3 and MMP-9 was similar to that of their net protein level; furthermore, the active form of MMP-1 was induced. Our results indicate that the TNF-alpha-induced morphological change of EA.hy 926 cells is associated not only with specific changes in the expression of PGs by the cells, but also with specific changes in the expression of MMPs.