Effect of nuclear factor-kappa B on vascular endothelial growth factor mRNA expression of human pulmonary artery smooth muscle cells in hypoxia.

In order to investigate the effect of nuclear factor-kappa B (NF-kappaB) on vascular endothelial growth factor (VEGF) mRNA expression of human pulmonary artery smooth muscle cells (HPASMCs) in hypoxia, the cultured HPASMCs in vitro were stimulated with pyrrolidine dithiocarbamate (PDTC), an inhibitor of NF-kappaB. The NF-kappaB p65 nuclei positive expression was detected by immunocytochemical technique. The IkappaBalpha protein expression was measured by Western blot. RT-PCR was used to detect the VEGF mRNA expression of HPASMCs. The results showed that no significant change was observed in the NF-kappaB p65 nuclei positive expression of cultured HPASMCs during 6 h-24 h in normoxia, but the levels of NF-kappaB p65 nuclei positive expression of cultured HPASMCs were significantly increased in hypoxia groups as compared with those in all normoxia groups (P<0.05). The IkappaBalpha protein expression of cultured HPASMCs showed no significant change during 6 h-24 h in normoxia, but significantly decreased in hypoxia as comapred with that in normoxia groups (P<0.05). PDTC (1 to 100 micromol/L) could inhibit the VEGF mRNA expression of HPASMCs in a concentration-dependent manner in hypoxia. In conclusion, NF-kappaB can be partly translocation activated from cytoplasm into nuclei in the cultured HPASMCs under hypoxia. The inhibition of NF-kappaB activation can decrease the VEGF mRNA expression. It is suggested that the activation of NF-kappaB is involved in the VEGF mRNA expression of HPASMCs under hypoxia.