Ouabain at pathological concentrations might induce damage vascular endothelial cells
Abstract
Aim: To examine the time- and dose-dependent effects of ouabain on human
umbilical vein endothelial cells (HUVEC) in vivo, and the changes in aortic endothelium
and the different expression levels of Kv4.2 in vitro. Methods: The proliferation
of HUVEC and cell death were determined by 3-(4,5-dimethylthiazol-2-yl)-
2,5-diphenyl-2H-tetrazolium bromide (MTT) assay, the incorporation of [3H]TdR,
trypan blue staining, and lactate dehydrogenase (LDH) release. The response of
endothelial cells to ouabain was explored with a complementary DNA microarray
and a candidate gene was found. “Ouabain-sensitive” hypertensive rats were
established by chronic administration of ouabain. Changes in the aortic endothelium
were observed by electron microscopy, and the expression level of Kv4.2 in
different animals was studied by using real-time quantitative reverse transcription-
polymerase chain reaction (RT-PCR). Results: Ouabain stimulated the proliferation
of HUVEC at physiological concentrations (0.3−0.9 nmol/L). Ouabain at
pathological concentrations (0.9−1.8 nmol/L) inhibited proliferation and induced
cell death. mRNA profile analysis indicated that 340 genes were differentially
expressed after ouabain treatment: 145 were upregulated, of which 6 were
upregulated significantly, including KCND2 (encoding the potassium voltagegated
channel shal-related subfamily member 2). The upregulated genes were
mainly related to cell metabolism and transcription. In ouabain-sensitive hypertensive
rats, the aortic endothelium was damaged and Kv4.2 (coded by KCND2)
was over-expressed. Conclusion: The physiological role of ouabain in HUVEC
might involve the control of growth and metabolism. Ouabain at pathological
concentrations might affect the structure and function of the vascular endothelium
by modification of expression of the KCND2 gene, and participate vascular
remodeling in hypertension.
Keywords:
umbilical vein endothelial cells (HUVEC) in vivo, and the changes in aortic endothelium
and the different expression levels of Kv4.2 in vitro. Methods: The proliferation
of HUVEC and cell death were determined by 3-(4,5-dimethylthiazol-2-yl)-
2,5-diphenyl-2H-tetrazolium bromide (MTT) assay, the incorporation of [3H]TdR,
trypan blue staining, and lactate dehydrogenase (LDH) release. The response of
endothelial cells to ouabain was explored with a complementary DNA microarray
and a candidate gene was found. “Ouabain-sensitive” hypertensive rats were
established by chronic administration of ouabain. Changes in the aortic endothelium
were observed by electron microscopy, and the expression level of Kv4.2 in
different animals was studied by using real-time quantitative reverse transcription-
polymerase chain reaction (RT-PCR). Results: Ouabain stimulated the proliferation
of HUVEC at physiological concentrations (0.3−0.9 nmol/L). Ouabain at
pathological concentrations (0.9−1.8 nmol/L) inhibited proliferation and induced
cell death. mRNA profile analysis indicated that 340 genes were differentially
expressed after ouabain treatment: 145 were upregulated, of which 6 were
upregulated significantly, including KCND2 (encoding the potassium voltagegated
channel shal-related subfamily member 2). The upregulated genes were
mainly related to cell metabolism and transcription. In ouabain-sensitive hypertensive
rats, the aortic endothelium was damaged and Kv4.2 (coded by KCND2)
was over-expressed. Conclusion: The physiological role of ouabain in HUVEC
might involve the control of growth and metabolism. Ouabain at pathological
concentrations might affect the structure and function of the vascular endothelium
by modification of expression of the KCND2 gene, and participate vascular
remodeling in hypertension.