Endothelial Cell Vasodilator Dysfunction Mediates Progressive Pregnancy-induced Hypertension in Endothelial Cell Tetrahydrobiopterin Deficient Mice

Abstract

Background and purpose: Pregnancy-associated vascular remodeling is essential for both maternal and fetal health. We have previously shown that maternal endothelial cell tetrahydrobiopterin (BH4) deficiency causes poor pregnancy outcomes. Here, we investigated the role and mechanisms of endothelial cell-mediated vasorelaxation function in these outcomes. Experimental approach: The vascular reactivity of mouse aortas and uterine arteries from non-pregnant and pregnant endothelial cell-specific BH4 deficient mice (Gch1fl/flTie2cre mice) was assessed by wire myography. Systolic blood pressure was assessed by tail cuff plethysmography. Key results: Key results: In late pregnancy, systolic blood pressure was significantly higher (~24 mmHg) in Gch1fl/flTie2cre mice compared with wild-type littermates. This was accompanied by enhanced vasoconstriction and reduced endothelial-dependent vasodilation in both aorta and uterine arteries from pregnant Gch1fl/flTie2cre mice. In uterine arteries loss of eNOS-derived vasodilators was partially compensated by upregulation of intermediate and large-conductance Ca2+-activated K+ channels. In rescue experiments, oral BH4 supplementation alone did not rescue vascular dysfunction and pregnancy-induced hypertension in pregnant Gch1fl/flTie2cre mice. However, combination with the fully reduced folate, 5-methyltetrahydrofolate (5-MTHF), restored endothelial cell vasodilator function and blood pressure. Conclusions and implications: We identify a critical requirement for maternal endothelial cell BH4 biosynthesis in endothelial cell vasodilator function in pregnancy. Targeting vascular Gch1 and BH4 biosynthesis with reduced folates may provide a novel therapeutic target for the prevention and treatment of pregnancy-related hypertension.

Novel Role of 5-Methyl-(6S)-Tetrahydrofolate in Mediating Endothelial Cell Tetrahydrobiopterin in Pregnancy and Implications for Gestational Hypertension

“…As in our previous studies, 18,19 maternal endothelial cell BH4 deficiency resulted in progressive hypertension and intrauterine growth restriction in pregnant Gch1 fl/fl Tie2cre mice (Figure 1B through 1D). Treatment with oral FA had no significant effect on systolic BP or fetal development during pregnancy in either wild-type or Gch1 fl/fl Tie2cre mice (Figure 1B through 1D).…”

“…We previously reported that maternal endothelial cell BH4 deficiency in Gch1 fl/fl Tie2cre mice leads to hypertension and reduced fetal growth. 18,19 We also demonstrated that oral supplementation of pregnant Gch1 fl/fl Tie2cre mice with BH4 and 5-MTHF, but not BH4 alone, was sufficient to restore endothelial function and prevent both fetal growth restriction and hypertension. 18,19 However, it is unclear whether 5-MTHF or FA alone can rescue these phenotypes associated with endothelial cell BH4 deficiency.…”

“…18,19 We also demonstrated that oral supplementation of pregnant Gch1 fl/fl Tie2cre mice with BH4 and 5-MTHF, but not BH4 alone, was sufficient to restore endothelial function and prevent both fetal growth restriction and hypertension. 18,19 However, it is unclear whether 5-MTHF or FA alone can rescue these phenotypes associated with endothelial cell BH4 deficiency. To address this, we treated female Gch1 fl/fl Tie2cre and wild-type littermates with either oral 5-MTHF (15 mg/kg mouse body weight per day) or a FA (15 mg/mouse body weight per day) or control diet (chow) for 3 days before mating and throughout pregnancy (Figure 1A).…”

“…These findings indicate that maternal endothelial cell BH4 plays a critical role in a normal pregnancy. 18,19,22 Oral BH4 plus 5-MTHF (but not BH4 alone) was sufficient to restore endothelial function and prevent both fetal growth restriction and hypertension in pregnant Gch1 fl/fl Tie2cre mice, 18,19 suggesting an important interaction between BH4 and folate metabolism. Furthermore, our previous studies in human vessels showed that 5-MTHF has beneficial effects on endothelial function and vascular superoxide production, by preventing peroxynitrite-mediated BH4 oxidation and improving eNOS coupling.…”

“…eNOS is a key regulator of vascular function, with particular importance in the cardiovascular adaptation to pregnancy, through its roles in the regulation of blood flow and blood pressure (BP). 18,19 In hypertensive pregnancy, vascular NO bioavailability is reduced and markers of oxidative stress are increased. 20,21 We have recently demonstrated that levels of BH4 and eNOS activity are markedly reduced in primary endothelial cells and placental extracellular vesicles obtained from women with hypertensive pregnancy, compared with normotensive pregnancies.…”

Novel Role of 5-Methyl-(6S)-Tetrahydrofolate in Mediating Endothelial Cell Tetrahydrobiopterin in Pregnancy and Implications for Gestational Hypertension

“…As in our previous studies, 18,19 maternal endothelial cell BH4 deficiency resulted in progressive hypertension and intrauterine growth restriction in pregnant Gch1 fl/fl Tie2cre mice (Figure 1B through 1D). Treatment with oral FA had no significant effect on systolic BP or fetal development during pregnancy in either wild-type or Gch1 fl/fl Tie2cre mice (Figure 1B through 1D).…”

“…We previously reported that maternal endothelial cell BH4 deficiency in Gch1 fl/fl Tie2cre mice leads to hypertension and reduced fetal growth. 18,19 We also demonstrated that oral supplementation of pregnant Gch1 fl/fl Tie2cre mice with BH4 and 5-MTHF, but not BH4 alone, was sufficient to restore endothelial function and prevent both fetal growth restriction and hypertension. 18,19 However, it is unclear whether 5-MTHF or FA alone can rescue these phenotypes associated with endothelial cell BH4 deficiency.…”

“…18,19 We also demonstrated that oral supplementation of pregnant Gch1 fl/fl Tie2cre mice with BH4 and 5-MTHF, but not BH4 alone, was sufficient to restore endothelial function and prevent both fetal growth restriction and hypertension. 18,19 However, it is unclear whether 5-MTHF or FA alone can rescue these phenotypes associated with endothelial cell BH4 deficiency. To address this, we treated female Gch1 fl/fl Tie2cre and wild-type littermates with either oral 5-MTHF (15 mg/kg mouse body weight per day) or a FA (15 mg/mouse body weight per day) or control diet (chow) for 3 days before mating and throughout pregnancy (Figure 1A).…”

“…These findings indicate that maternal endothelial cell BH4 plays a critical role in a normal pregnancy. 18,19,22 Oral BH4 plus 5-MTHF (but not BH4 alone) was sufficient to restore endothelial function and prevent both fetal growth restriction and hypertension in pregnant Gch1 fl/fl Tie2cre mice, 18,19 suggesting an important interaction between BH4 and folate metabolism. Furthermore, our previous studies in human vessels showed that 5-MTHF has beneficial effects on endothelial function and vascular superoxide production, by preventing peroxynitrite-mediated BH4 oxidation and improving eNOS coupling.…”

“…eNOS is a key regulator of vascular function, with particular importance in the cardiovascular adaptation to pregnancy, through its roles in the regulation of blood flow and blood pressure (BP). 18,19 In hypertensive pregnancy, vascular NO bioavailability is reduced and markers of oxidative stress are increased. 20,21 We have recently demonstrated that levels of BH4 and eNOS activity are markedly reduced in primary endothelial cells and placental extracellular vesicles obtained from women with hypertensive pregnancy, compared with normotensive pregnancies.…”

Novel Role of 5-Methyl-(6S)-Tetrahydrofolate in Mediating Endothelial Cell Tetrahydrobiopterin in Pregnancy and Implications for Gestational Hypertension

“…As in our previous studies, 18,19 maternal endothelial cell BH4 deficiency resulted in progressive hypertension and intrauterine growth restriction in pregnant Gch1 fl/fl Tie2cre mice (Figure 1B through 1D). Treatment with oral FA had no significant effect on systolic BP or fetal development during pregnancy in either wild-type or Gch1 fl/fl Tie2cre mice (Figure 1B through 1D).…”

“…We previously reported that maternal endothelial cell BH4 deficiency in Gch1 fl/fl Tie2cre mice leads to hypertension and reduced fetal growth. 18,19 We also demonstrated that oral supplementation of pregnant Gch1 fl/fl Tie2cre mice with BH4 and 5-MTHF, but not BH4 alone, was sufficient to restore endothelial function and prevent both fetal growth restriction and hypertension. 18,19 However, it is unclear whether 5-MTHF or FA alone can rescue these phenotypes associated with endothelial cell BH4 deficiency.…”

“…18,19 We also demonstrated that oral supplementation of pregnant Gch1 fl/fl Tie2cre mice with BH4 and 5-MTHF, but not BH4 alone, was sufficient to restore endothelial function and prevent both fetal growth restriction and hypertension. 18,19 However, it is unclear whether 5-MTHF or FA alone can rescue these phenotypes associated with endothelial cell BH4 deficiency. To address this, we treated female Gch1 fl/fl Tie2cre and wild-type littermates with either oral 5-MTHF (15 mg/kg mouse body weight per day) or a FA (15 mg/mouse body weight per day) or control diet (chow) for 3 days before mating and throughout pregnancy (Figure 1A).…”

“…These findings indicate that maternal endothelial cell BH4 plays a critical role in a normal pregnancy. 18,19,22 Oral BH4 plus 5-MTHF (but not BH4 alone) was sufficient to restore endothelial function and prevent both fetal growth restriction and hypertension in pregnant Gch1 fl/fl Tie2cre mice, 18,19 suggesting an important interaction between BH4 and folate metabolism. Furthermore, our previous studies in human vessels showed that 5-MTHF has beneficial effects on endothelial function and vascular superoxide production, by preventing peroxynitrite-mediated BH4 oxidation and improving eNOS coupling.…”

“…eNOS is a key regulator of vascular function, with particular importance in the cardiovascular adaptation to pregnancy, through its roles in the regulation of blood flow and blood pressure (BP). 18,19 In hypertensive pregnancy, vascular NO bioavailability is reduced and markers of oxidative stress are increased. 20,21 We have recently demonstrated that levels of BH4 and eNOS activity are markedly reduced in primary endothelial cells and placental extracellular vesicles obtained from women with hypertensive pregnancy, compared with normotensive pregnancies.…”

Novel Role of 5-Methyl-(6S)-Tetrahydrofolate in Mediating Endothelial Cell Tetrahydrobiopterin in Pregnancy and Implications for Gestational Hypertension

“…As in our previous studies, 18,19 maternal endothelial cell BH4 deficiency resulted in progressive hypertension and intrauterine growth restriction in pregnant Gch1 fl/fl Tie2cre mice (Figure 1B through 1D). Treatment with oral FA had no significant effect on systolic BP or fetal development during pregnancy in either wild-type or Gch1 fl/fl Tie2cre mice (Figure 1B through 1D).…”

“…We previously reported that maternal endothelial cell BH4 deficiency in Gch1 fl/fl Tie2cre mice leads to hypertension and reduced fetal growth. 18,19 We also demonstrated that oral supplementation of pregnant Gch1 fl/fl Tie2cre mice with BH4 and 5-MTHF, but not BH4 alone, was sufficient to restore endothelial function and prevent both fetal growth restriction and hypertension. 18,19 However, it is unclear whether 5-MTHF or FA alone can rescue these phenotypes associated with endothelial cell BH4 deficiency.…”

“…18,19 We also demonstrated that oral supplementation of pregnant Gch1 fl/fl Tie2cre mice with BH4 and 5-MTHF, but not BH4 alone, was sufficient to restore endothelial function and prevent both fetal growth restriction and hypertension. 18,19 However, it is unclear whether 5-MTHF or FA alone can rescue these phenotypes associated with endothelial cell BH4 deficiency. To address this, we treated female Gch1 fl/fl Tie2cre and wild-type littermates with either oral 5-MTHF (15 mg/kg mouse body weight per day) or a FA (15 mg/mouse body weight per day) or control diet (chow) for 3 days before mating and throughout pregnancy (Figure 1A).…”

“…These findings indicate that maternal endothelial cell BH4 plays a critical role in a normal pregnancy. 18,19,22 Oral BH4 plus 5-MTHF (but not BH4 alone) was sufficient to restore endothelial function and prevent both fetal growth restriction and hypertension in pregnant Gch1 fl/fl Tie2cre mice, 18,19 suggesting an important interaction between BH4 and folate metabolism. Furthermore, our previous studies in human vessels showed that 5-MTHF has beneficial effects on endothelial function and vascular superoxide production, by preventing peroxynitrite-mediated BH4 oxidation and improving eNOS coupling.…”

“…eNOS is a key regulator of vascular function, with particular importance in the cardiovascular adaptation to pregnancy, through its roles in the regulation of blood flow and blood pressure (BP). 18,19 In hypertensive pregnancy, vascular NO bioavailability is reduced and markers of oxidative stress are increased. 20,21 We have recently demonstrated that levels of BH4 and eNOS activity are markedly reduced in primary endothelial cells and placental extracellular vesicles obtained from women with hypertensive pregnancy, compared with normotensive pregnancies.…”