Effects of soluble endoglin on nitric oxide production and nitric oxide synthase phosphorylation in cultured human umbilical vein endothelial cells / 中华围产医学杂志

ABSTRACT

Objective To investigate the effects of soluble endoglin(sEng)on nitric oxide (NO)production and endothelial nitric oxide synthase(eNOS)phosphorylation in cultured human umbilical vein endothelial cells.Methods Human umbilical vein endothelial cells within 3 passages seeded in culture plates of 96 wells,were stimulated by total culture medium(control group)or sEng (1,10 and 100 μg/L)respectively.Cells and medium were collected after cells were cultured for 6,12 and 24 hours respectively.The concentration of the metabolites of NO in each group was measured by nitrate reductase method.The expression of eNOS and eNOS-Ser(p)1177 were detected by Western blot.The expression of eNOS mRNA in each group was detected by real-time fluorescence reverse transcription-polymerase chain reaction.Analysis of variance,LSD method and pearson correlation were used to compare the difference between groups.Results(1)The concentration of the metabolites of NO in 1,10 and 100μg/L sEng groups was(59.25±1.63),(41.08±2.71)and (30.38±1.63)μmol/L respectively after cultured for 6 hours;(54.98±3.34),(35.00±8.60)and (19.82±3.75)μmol/L for 12 hours; and(46.14±4.93),(30.24±2.08)and(12.78±5.01)μmol/L for 24 hours.There was no significant changes in control group with time going by(F=2.30,P=0.14).The concentration of the metabolites of NO was significantly lower in sEng group,and which had negative correlation with culture time(r=-0.98,P＜0.05)and dose(r=-0.88,P＜0.05).(2)The expression of eNOS in 1,10,100 μg/L sEng groups was 0.71 ± 0.00,0.47 ± 0.00 and 0.32±0.00 after cultured for 6 hours; 0.58±0.00,0.42±0.00 and 0.25±0.00 for 12 hours; and 0.49±0.00,0.33±0.00 and 0.18±0.00 for 24 hours.While the expression of eNOS and eNOS-Ser (p)1177/eNOS had no significant changes in control group with time going by(F=3.59 and 0.37,P=0.09 and 0.80).The expression of eNOS protein and eNOS-Ser(p)1177 decreased significantly in sEng groups,which had negative correlation with culture time(r=0.98 and-0.96,P＜0.05)and dose(r=-0.76 and-0.79,P＜0.05).(3)The expression of eNOS mRNA decreased significantly in sEng groups.Which also had negative correlation with culture time(r=-0.51,P＜0.05)and dose(r=-0.82,P＜0.05).Conclusions sEng might inhibit eNOS activity by blocking 1177 Ser phosphorylation to decrease NO production.