Retrovirus-mediated human heme oxygenase-1 (HO-1) gene transfer into rat endothelial cells: the effect of HO-1 inducers on the expression of cytokines.

The present study was conducted to investigate if the mechanism of human heme oxygenase-1 (HO-1) mediated angiogenesis was through the induction of vascular endothelial growth factor (VEGF). Also, the effect of HO-1 on the expression of transforming growth factor beta (TGF-beta),was studied in the presence and absence of HO-1 inducers. Rat lung microvessel endothelial cell line transduced with human HO-1 gene was subjected to cell culture (six separate experiments). mRNA extraction and reverse transcriptase polymerase chain reaction (RT-PCR) experiments, were performed to evaluate the expression of HO-1, VEGF, and TGF-beta in the presence and absence of HO inducers including H(2)O(2), endotoxin and snake venom metalloproteinase with disintegrin like activity(SnMP). ELISA technique was performed to evaluate the levels of the studied growth factors. The results of the study showed over expression of VEGF in endothelial cells transduced with HO-1 compared to control non-transduced endothelial cells. On the other hand, the expression of TGF-beta and its protein level were markedly inhibited in HO-1 transduced endothelial cells compared to control non-transduced cells. Endotoxin and SnMP showed more prominent effect on the expression of VEGF and suppression of TGF-beta in HO-1 transduced endothelial cells, suggesting that their effect is most probably mediated through induction of HO-1.