scholarly journals [Ca2+]i signaling vs. eNOS expression as determinants of NO output in uterine artery endothelium: relative roles in pregnancy adaptation and reversal by VEGF165

2011 ◽  
Vol 300 (4) ◽  
pp. H1182-H1193 ◽  
Author(s):  
Fu-Xian Yi ◽  
Derek S. Boeldt ◽  
Ronald R. Magness ◽  
Ian M. Bird
Keyword(s):  
Nitric Oxide ◽  
Blood Flow ◽  
Luteal Phase ◽  
Maximum Rate ◽  
Uterine Artery ◽  
Follicular Phase ◽  
No Production ◽  
Uterine Blood Flow ◽  
Enos Expression ◽  
In Pregnancy

Pregnancy is a time of greatly increased uterine blood flow to meet the needs of the growing fetus. Increased uterine blood flow is also observed in the follicular phase of the ovarian cycle. Simultaneous fura-2 and 4,5-diaminofluoresceine (DAF-2) imaging reveals that cells of the uterine artery endothelium (UA Endo) from follicular phase ewes produce marginally more nitric oxide (NO) in response to ATP than those from luteal phase. However, this is paralleled by changes in NO in response to ionomycin, suggesting this is solely due to higher levels of endothelial nitric oxide synthase (eNOS) protein in the follicular phase. In contrast, UA Endo from pregnant ewes (P-UA Endo) produces substantially more NO (4.62-fold initial maximum rate, 2.56-fold overall NO production) in response to ATP, beyond that attributed to eNOS levels alone (2.07-fold initial maximum rate, 1.93-fold overall with ionomycin). The ATP-stimulated intracellular free calcium concentration ([Ca2+]i) response in individual cells of P-UA Endo comprises an initial peak followed by transient [Ca2+]i bursts that are limited in the luteal phase, not altered in the follicular phase, but are sustained in pregnancy and observed in more cells. Thus pregnancy adaptation of UA Endo NO output occurs beyond the level of eNOS expression and likely through associated [Ca2+]i cell signaling changes. Preeclampsia is a condition of a lack of UA Endo adaptation and poor NO production/vasodilation and is associated with elevated placental VEGF165. While treatment of luteal NP-UA Endo and P-UA Endo with VEGF165 acutely stimulates a very modest [Ca2+]i and NO response, subsequent stimulation of the same vessel with ATP results in a blunted [Ca2+]i and an associated NO response, with P-UA Endo reverting to the response of luteal NP-UA Endo. This demonstrates the importance of adaptation of cell signaling over eNOS expression in pregnancy adaptation of uterine endothelial function and further implicates VEGF in the pathophysiology of preeclampsia.

Endothelial vasodilator production by uterine and systemic arteries. VI. Ovarian and pregnancy effects on eNOS and NOx

2001 ◽  
Vol 280 (4) ◽  
pp. H1692-H1698 ◽  
Author(s):  
Ronald R. Magness ◽  
Jeremy A. Sullivan ◽  
Yun Li ◽  
Terrance M. Phernetton ◽  
Ian M. Bird
Keyword(s):  
Nitric Oxide ◽  
Blood Flow ◽  
Mrna Level ◽  
Follicular Phase ◽  
Ovarian Cycle ◽  
No Production ◽  
Mrna Levels ◽  
Uterine Blood Flow ◽  
Enos Mrna ◽  
Enos Protein

Normal pregnancy and the follicular phase of the ovarian cycle are both estrogen-dominated physiological states that are characterized by elevations in uterine blood flow and endothelial nitric oxide synthase (eNOS) protein expression in the uterine artery (UA) endothelium. It is unknown if elevations in mRNA level account for the changes in protein or eNOS activity. We tested the hypothesis that pregnancy and the follicular phase are associated with increases in eNOS mRNA and the consequent elevated expression of eNOS protein results in increased circulating nitric oxide (NO) levels. UA were obtained from pregnant (PREG; n = 8; 110–130 days gestation; term = 145 ± 3 days), nonpregnant luteal (LUT; n = 6), nonpregnant follicular (FOL; n= 6), and nonpregnant ovariectomized (OVEX; n = 6) sheep. Circulating NO levels were analyzed as total NO2-NO3 (NOx). Western analysis performed on UA endothelial-isolated proteins demonstrated that eNOS protein levels were OVEX = LUT ≤ FOL < PREG ( P < 0.05), whereas eNOS mRNA expression (RT-PCR) in UA endothelial cells obtained by limited collagenase digestion was OVEX < LUT < FOL < PREG ( P < 0.05). Pregnancy dramatically elevated eNOS protein (4.1- to 6.9-fold) and mRNA (2.4- to 6.9-fold) over LUT controls ( P < 0.01). Circulating NOx levels were not altered by ovariectomy or the ovarian cycle but were elevated from 4.4 ± 1.1 μM in LUT to 12 ± 4, 22 ± 3, and 41 ± 3 μM at 110, 120, and 130 days gestation ( P < 0.01). Systemic NOxlevels in singleton (12.5 ± 1.6 μM) were less ( P < 0.01) than in multiple (twin 27.6 ± 6.5 μM; triplet = 46 ± 10 μM) pregnancies. Therefore, the follicular phase and, to a much greater extent, pregnancy are associated with elevations in UA endothelium-derived eNOS expression, although significant increases in systemic NOx levels were only observed in the PREG group (multiple > singleton). Thus, although UA endothelial increases in eNOS protein and mRNA levels are associated with high estrogen states, increases in local UA NO production may require additional eNOS protein activation to play its important role in the maintenance of uterine blood flow in pregnancy.

scholarly journals Estrogen Receptors and Estrogen-Induced Uterine Vasodilation in Pregnancy

2020 ◽  
Vol 21 (12) ◽  
pp. 4349 ◽  
Author(s):  
Jin Bai ◽  
Qian-Rong Qi ◽  
Yan Li ◽  
Robert Day ◽  
Josh Makhoul ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Blood Flow ◽  
Uterine Artery ◽  
Normal Pregnancy ◽  
Uterine Blood Flow ◽  
Growth And Survival ◽  
Respiratory Gases ◽  
G Protein Coupled ◽  
In Pregnancy

Normal pregnancy is associated with dramatic increases in uterine blood flow to facilitate the bidirectional maternal–fetal exchanges of respiratory gases and to provide sole nutrient support for fetal growth and survival. The mechanism(s) underlying pregnancy-associated uterine vasodilation remain incompletely understood, but this is associated with elevated estrogens, which stimulate specific estrogen receptor (ER)-dependent vasodilator production in the uterine artery (UA). The classical ERs (ERα and ERβ) and the plasma-bound G protein-coupled ER (GPR30/GPER) are expressed in UA endothelial cells and smooth muscle cells, mediating the vasodilatory effects of estrogens through genomic and/or nongenomic pathways that are likely epigenetically modified. The activation of these three ERs by estrogens enhances the endothelial production of nitric oxide (NO), which has been shown to play a key role in uterine vasodilation during pregnancy. However, the local blockade of NO biosynthesis only partially attenuates estrogen-induced and pregnancy-associated uterine vasodilation, suggesting that mechanisms other than NO exist to mediate uterine vasodilation. In this review, we summarize the literature on the role of NO in ER-mediated mechanisms controlling estrogen-induced and pregnancy-associated uterine vasodilation and our recent work on a “new” UA vasodilator hydrogen sulfide (H2S) that has dramatically changed our view of how estrogens regulate uterine vasodilation in pregnancy.

Uterine artery pseudoaneurysm and embolisation during pregnancy

2020 ◽  
Vol 13 (5) ◽  
pp. e234058
Author(s):  
Jared T Roeckner ◽  
Adetola F Louis-Jacques ◽  
Bruce R Zwiebel ◽  
Judette M Louis
Keyword(s):  
Blood Flow ◽  
Uterine Artery ◽  
Thrombin Injection ◽  
Uterine Blood Flow ◽  
Coil Embolisation ◽  
Artery Pseudoaneurysm ◽  
Healthy Young Woman ◽  
Dangerous Condition ◽  
Uterine Artery Pseudoaneurysm ◽  
In Pregnancy

Uterine artery pseudoaneurysm in pregnancy is a dangerous condition as rupture can be catastrophic due to the large volume of uterine blood flow. We present a case of a healthy, young woman with a desired pregnancy at 15 weeks of gestation incidentally discovered to have a pseudoaneurysm of the uterine artery during a routine prenatal ultrasound. She underwent initial thrombin injection followed by endovascular coil embolisation of the left uterine artery and carried the pregnancy to term without further complications.

Functional role of angiotensin II type 1 and 2 receptors in regulation of uterine blood flow in nonpregnant sheep

2000 ◽  
Vol 278 (2) ◽  
pp. H353-H359 ◽  
Author(s):  
Donna S. Lambers ◽  
Suzanne G. Greenberg ◽  
Kenneth E. Clark
Keyword(s):  
Nitric Oxide ◽  
Blood Flow ◽  
Angiotensin Ii ◽  
Uterine Artery ◽  
Receptor Subtype ◽  
Ang Ii ◽  
Uterine Blood Flow ◽  
Response Curves ◽  
Vascular Responses

The objective was to determine the receptor subtype of angiotensin II (ANG II) that is responsible for vasoconstriction in the nonpregnant ovine uterine and systemic vasculatures. Seven nonpregnant estrogenized ewes with indwelling uterine artery catheters and flow probes received bolus injections (0.1, 0.3 and 1 μg) of ANG II locally into the uterine artery followed by a systemic infusion of ANG II at 100 ng ⋅ kg−1 ⋅ min−1for 10 min to determine uterine vasoconstrictor responses. Uterine ANG II dose-response curves were repeated following administration of the ANG II type 2 receptor (AT2) antagonist PD-123319 and then repeated again in the presence of an ANG II type 1 receptor (AT1) antagonist L-158809. In a second experiment, designed to investigate the mechanism of ANG II potentiation that occurred in the presence of AT2 blockade, nonestrogenized sheep received a uterine artery infusion of L-158809 (3 mg/min for 5 min) prior to the infusion of 0.03 μg/min of ANG II for 10 min. ANG II produced dose-dependent decreases in uterine blood flow ( P < 0.03), which were potentiated in the presence of the AT2 antagonist ( P < 0.02). Addition of the AT1 antagonist abolished the uterine vascular responses and blocked ANG II-induced increases in systemic arterial pressure ( P < 0.01). Significant uterine vasodilation ( P < 0.01) was noted with AT1 blockade in the second experiment, which was reversed by administration of the AT2 antagonist or by the nitric oxide synthetase inhibitor N ω-nitro-l-arginine methyl ester. We conclude that the AT1- receptors mediate the systemic and uterine vasoconstrictor responses to ANG II in the nonpregnant ewe. AT2-receptor blockade resulted in a potentiation of the uterine vasoconstrictor response to ANG II, suggesting that the AT2-receptor subtype may modulate uterine vascular responses to ANG II potentially by release of nitric oxide.

scholarly journals eNOS activation and NO function: Pregnancy adaptive programming of capacitative entry responses alters nitric oxide (NO) output in vascular endothelium–new insights into eNOS regulation through adaptive cell signaling

2011 ◽  
Vol 210 (3) ◽  
pp. 243-258 ◽  
Author(s):  
D S Boeldt ◽  
F X Yi ◽  
I M Bird
Keyword(s):  
Nitric Oxide ◽  
Endothelial Cells ◽  
Gap Junction ◽  
Uterine Artery ◽  
Umbilical Vein ◽  
Normal Pregnancy ◽  
Human Hand ◽  
No Production ◽  
Trpc Channels ◽  
Enos Expression

In pregnancy, vascular nitric oxide (NO) production is increased in the systemic and more so in the uterine vasculature, thereby supporting maximal perfusion of the uterus. This high level of functionality is matched in the umbilical vein, and in corresponding disease states such as pre-eclampsia, reduced vascular responses are seen in both uterine artery and umbilical vein. In any endothelial cell, NO actually produced by endothelial NO synthase (eNOS) is determined by the maximum capacity of the cell (eNOS expression levels), eNOS phosphorylation state, and the intracellular [Ca2+]iconcentration in response to circulating hormones or physical forces. Herein, we discuss how pregnancy-specific reprogramming of NO output is determined as much by pregnancy adaptation of [Ca2+]isignaling responses as it is by eNOS expression and phosphorylation. By examining the changes in [Ca2+]isignaling responses from human hand vein endothelial cells, uterine artery endothelial cells, and human umbilical vein endothelial cells in (where appropriate) nonpregnant, normal pregnant, and pathological pregnant (pre-eclamptic) state, it is clear that pregnancy adaptation of NO output occurs at the level of sustained phase ‘capacitative entry’ [Ca2+]iresponse, and the adapted response is lacking in pre-eclamptic pregnancies. Moreover, gap junction function is an essential permissive regulator of the capacitative response and impairment of NO output results from any inhibitor of gap junction function, or capacitative entry using TRPC channels. Identifying these [Ca2+]isignaling mechanisms underlying normal pregnancy adaptation of NO output not only provides novel targets for future treatment of diseases of pregnancy but may also apply to other common forms of hypertension.

Regulation of endothelial nitric oxide synthase by PGD2 in the developing choroid

2000 ◽  
Vol 278 (1) ◽  
pp. H60-H66 ◽  
Author(s):  
Isabelle Dumont ◽  
Pierre Hardy ◽  
Krishna G. Peri ◽  
Xin Hou ◽  
Stéphane Molotchnikoff ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Blood Flow ◽  
Nitric Oxide Synthase ◽  
No Production ◽  
Enos Expression ◽  
Choroidal Blood Flow ◽  
Nitrite Production ◽  
Enos Mrna ◽  
Oxide Synthase

We investigated if prostaglandins might regulate the increased choroidal endothelial (e) nitric oxide synthase (NOS) expression in the perinate. Prostaglandins, eNOS mRNA, immunoreactive protein and activity, and nitrite [stable metabolite of nitric oxide (NO)] production were markedly higher in newborn (1 day old) than juvenile (6–8 wk old) pig choroid. Treatment of isolated newborn choroids with the prostaglandin synthase inhibitor ibuprofen for 24 h reduced eNOS mRNA and nitrite production to values in juveniles. This effect was equally observed with the PGD2 receptor (DP) blocker BW A868C and was prevented by cotreatment with PGD2 but not other prostaglandins; similar observations were made on NOS activity in vivo. PGD2 also increased eNOS expression on choroids of juveniles, and this effect was blocked by BW A868C. The manifestation of this upregulation of eNOS by PGD2 on the control of choroidal vasomotor response was tested by using NO-dependent vasorelaxants, ACh, bradykinin (Bk), and substance P (SP). ACh-, Bk-, and SP-elicited choroidal vasorelaxation was greater in saline-treated newborn than juvenile pigs. Ibuprofen (24 h) decreased ACh-, Bk-, and SP-evoked vasorelaxation in newborns, whereas PGD2 increased that in juveniles and prevented the ibuprofen-induced attenuated relaxation in newborns; infusion of N ω-monomethyl-l-arginine in choroids of those animals treated with PGD2 reversed the augmented vasorelaxation to ACh, Bk, and SP. Finally, PGD2-induced upregulation of NOS in the perinate was also reflected by curtailed choroidal blood flow autoregulatory response to increased perfusion pressure. In conclusion, PGD2 exhibits a major role in upregulating eNOS expression and activity in the choroid, which in turn results in greater NO-mediated vasorelaxation; a new mechanism for eNOS regulation via DP is hereby disclosed. The relationship between PGD2 and eNOS in the developing subject provides an explanation for the interactive role of these two factors in the absent choroidal blood flow autoregulation in the perinate.

Simultaneous imaging of [Ca2+]i and intracellular NO production in freshly isolated uterine artery endothelial cells: effects of ovarian cycle and pregnancy

2005 ◽  
Vol 288 (1) ◽  
pp. R140-R148 ◽  
Author(s):  
Fu-Xian Yi ◽  
Ronald R. Magness ◽  
Ian M. Bird
Keyword(s):  
Uterine Artery ◽  
Cell Model ◽  
Calcium Ionophore ◽  
Fold Increase ◽  
Follicular Phase ◽  
Ovarian Cycle ◽  
No Production ◽  
Enos Expression ◽  
Indirect Measures

Pregnancy and the follicular phase of the ovarian cycle show elevation of uterine blood flow and associated increases in uterine artery endothelium (UAE) endothelial nitric oxide (NO) synthase (eNOS) expression. Nonetheless, a role for increased NO production during pregnancy and the follicular phase has only been inferred by indirect measures. The recent development of a uterine artery endothelial cell model further suggests that pregnancy is associated with reprogramming of cell signaling, such that eNOS may become more Ca2+ sensitive and be subject to regulation by Ca2+-independent kinases. This study describes for the first time the direct and simultaneous monitoring of NO production and intracellular free Ca2+ concentration ([Ca2+]i) in freshly isolated UAE from pregnant, follicular, and luteal sheep. The pharmacological agonists ionomycin (calcium ionophore) and thapsigargin (TG; endoplasmic reticulum Ca2+ pump inhibitor) were used to maximally elevate [Ca2+]i and fully activate eNOS as a measure of eNOS expression. NO production stimulated by ionomycin (5 μM) and TG (10 μM) were 1.95- and 2.05-fold, respectively, in pregnant-UAE and 1.34- and 1.37-fold in follicular-UAE compared with luteal-UAE. In contrast, the physiological agonist ATP (100 μM) stimulated a 3.43-fold increase in NO in pregnant-UAE and a 1.90-fold increase in follicular-UAE compared with luteal-UAE, suggesting that pregnancy and follicular phase enhance eNOS activation beyond changes in expression in vivo. 2-aminoethoxydiphenyl borate (APB; an inositol 1,4,5-trisphosphate receptor blocker) totally prevented the ATP-induced [Ca2+]i response but only partially inhibited NO production. Thus pregnancy-enhanced eNOS activation in UAE is mediated through [Ca2+]i-insensitive pathways as well as through a greater eNOS sensitivity to [Ca2+]i.

scholarly journals Protein kinase Cδ regulates endothelial nitric oxide synthase expression via Akt activation and nitric oxide generation

2008 ◽  
Vol 294 (3) ◽  
pp. L582-L591 ◽  
Author(s):  
Neetu Sud ◽  
Stephen Wedgwood ◽  
Stephen M. Black
Keyword(s):  
Nitric Oxide ◽  
Nitric Oxide Synthase ◽  
Endothelial Nitric Oxide Synthase ◽  
Promoter Activity ◽  
Dominant Negative ◽  
No Production ◽  
Enos Expression ◽  
Akt Activation ◽  
Oxide Synthase ◽  
Endothelial Nitric Oxide

In this study, we explore the roles of the delta isoform of PKC (PKCδ) in the regulation of endothelial nitric oxide synthase (eNOS) activity in pulmonary arterial endothelial cells isolated from fetal lambs (FPAECs). Pharmacological inhibition of PKCδ with either rottlerin or with the peptide, δV1-1, acutely attenuated NO production, and this was associated with a decrease in phosphorylation of eNOS at Ser1177 (S1177). The chronic effects of PKCδ inhibition using either rottlerin or the overexpression of a dominant negative PKCδ mutant included the downregulation of eNOS gene expression that was manifested by a decrease in both eNOS promoter activity and protein expression after 24 h of treatment. We also found that PKCδ inhibition blunted Akt activation as observed by a reduction in phosphorylated Akt at position Ser473. Thus, we conclude that PKCδ is actively involved in the activation of Akt. To determine the effect of Akt on eNOS signaling, we overexpressed a dominant negative mutant of Akt and determined its effect of NO generation, eNOS expression, and phosphorylation of eNOS at S1177. Our results demonstrated that Akt inhibition was associated with decreased NO production that correlated with reduced phosphorylation of eNOS at S1177, and decreased eNOS promoter activity. We next evaluated the effect of endogenously produced NO on eNOS expression by incubating FPAECs with the eNOS inhibitor 2-ethyl-2-thiopseudourea (ETU). ETU significantly inhibited NO production, eNOS promoter activity, and eNOS protein levels. Together, our data indicate involvement of PKCδ-mediated Akt activation and NO generation in maintaining eNOS expression.

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