Hypoxia down-regulates secretion of MMP-2, MMP-9 in porcine pulmonary artery endothelial and smooth muscle cells and the role of HIF-1

Primary cell culture, techniques of gene transfection, gelatin zymography, and Western blot were used to investigate the effect of hypoxia on the secretion of MMP-2 and MMP-9 in pulmonary artery endothelial cells (PAEC) and smooth muscle cells (PASMC), and the role of HIF-1, Our results showed that (1) after exposure to hypoxia for 24 h, the protein content and activity of MMP-2 in the PAEC medium as well as these of MMP-2 and MMP-9 in PASMC medium (P<0. 01) decreased significantly in contrast to those in normoxic group (P′<0.05); (2) after transfection of wild type EPO3′-enhancer, a HIF-1 decoy, the content and activity of MMP-2 and MMP-9 in hypoxic mediums became higher than those in normoxic group (P<0.01), while transfection of mutant EPO3′-enhancer didn't affect the hypoxia-induced down-regulation. It is concluded that hypoxia could inhibit the secretion and activity of MMP-2 and MMP-9 in PAEC and PASMC, which could be mitigated by the transfection of EPO3′-enhancer and that HIF-1 pathway might contribute to hypoxia-induced down-regulation of MMP-2 and MMP-9.