Abstract 9065: Na+/H+ Exchanger 1 Gene Regulates Migration of Human Pulmonary Artery Smooth Muscle Cells Under Hypoxia
Introduction: The Na+/H+ exchanger isoform 1 (NHE1) is ubiquitously expressed in many mammalian cell types, including pulmonary artery smooth muscle cell (PASMC). Our previous study has found that deficiency of the NHE1 gene prevented the development of hypoxia-induced pulmonary hypertension and vascular remodeling in mice. Since reports have shown that PASMC migration plays an important role in development of pulmonary hypertension, we thus in this study investigated effect of NHE1 gene on regulation of human PASMC migration under hypoxia. We assessed the hypothesis that inhibition of NHE1 gene expression will decrease hypoxia-induced PASMC migration.
Methods: Wound healing assay was performed for this study. Human PASMCs were transfected with NHE1 siRNA and then seeded in 12-well cell culture plates. After 24 hours, three straight scratches for each well were made with a pipette tip, rinsed with PBS, replaced with regular media and then incubated the cell under 2% hypoxia for 24 hours. After 24 hours of culture, the cells were removed from hypoxia and pictures on the scratched gap were taken. The migration was determined by counting the cell number in the gap.
Results: We found a significant increase in PASMC migration after the PASMCs were cultured under 2% hypoxia for 24 hours. The cell number in the scratched gap was 39.4 ± 4.2 in normoxia group (n=9) and 89.5 ± 5.5 in hypoxia group (n=9) (p<0.01). In the meantime, we found that the NHE1 siRNA transfection significantly inhibited hypoxia-induced PASMC migration. The cell number in the gap was 89.5 ± 5.5 in hypoxia control group (n=9) and 20.2 ± 1.1 in hypoxia NHE1 siRNA group (n=9) (p<0.01). The NHE1 siRNA transfection also significantly inhibited PASMC migration under normoxia. The cell number in the gap was 39.4 ± 4.2 in normoxia control (n=9) and 23.1 ± 3.0 in normoxia NHE1 siRNA group (n=9) (p<0.01).
Conclusion: Our data demonstrated that inhibition of NHE1 gene by siRNA significantly decreased hypoxia-induced migration of human PASMCs. This study provides evidence that NHE1 gene is involved in regulation of PASMC migration in development of pulmonary hypertension and vascular remodeling.
- © 2010 by American Heart Association, Inc.