Additive effects of low concentrations of estradiol-17β and progesterone on nitric oxide production by human vascular endothelial cells through shared signaling pathways

Estrogen Inhibits the Phenotypic Switching of Vascular Smooth Muscle Cells through ER-α/CREB in Aortic Dissection

Objective: To examine the alterations in estrogen levels in patients with aortic dissection (AD) and its protective effect on AD patients through the inhibition of vascular smooth muscle cells (VSMCs) phenotypic switching via the ER-α/CREB pathway. Methods: Demographic data were collected to assess sex disparity in AD patients, and serum 17β-estradiol (E2) levels were measured using ELISA. Phenotypic switching markers were analyzed in aortic tissues from AD patients and controls. Bioinformatics analysis identified estrogen-related pathways, focusing on the ER-α/CREB axis, with expression levels confirmed via immunohistochemistry and Western blot. AD mouse models were developed in male and ovariectomized female mice, with the effects of E2 supplementation on AD progression and VSMCs phenotypic switching evaluated. An AD cellular model was also employed to verify these findings through targeted pathway inhibition. Results: AD prevalence was higher in males, with reduced serum E2 levels observed in both male and postmenopausal female patients. Ovariectomized female mice showed increased AD incidence, while E2 supplementation reduced AD progression by inhibiting the phenotypic switching of VSMCs. Downregulation of ER-α and p-CREB/CREB expression was observed in AD patients, and E2 enhanced ER-α expression and CREB phosphorylation, preventing VSMC phenotypic switching. E2 also promoted ER-α/CREB interaction, and silencing ER-α inhibited CREB phosphorylation, leading to increased VSMC phenotypic switching. Conclusions: Estrogen (E2) plays a crucial role in preventing AD by maintaining VSMCs synthetic phenotype through the ER-α/CREB signaling pathway, providing a protective effect against the development of AD.

Regulation of mitochondrial dysfunction by estrogens and estrogen receptors in Alzheimer's disease: A focused review

Alzheimer's disease (AD) is a neurodegenerative disorder that primarily manifests itself by progressive memory loss and cognitive decline, thus significantly affecting memory functions and quality of life. In this review, we proceed from the understanding that the canonical amyloid-β hypothesis, while significant, has faced setbacks, highlighting the need to adopt a broader perspective considering the intricate interplay of diverse pathological pathways for effective AD treatments. Sex differences in AD offer valuable insights into a better understanding of its pathophysiology. Fluctuation of the levels of ovarian sex hormones during perimenopause is associated with changes in glucose metabolism, as a possible window of opportunity to further understand the roles of sex steroid hormones and their associated receptors in the pathophysiology of AD. We review these dimensions, emphasizing the potential of estrogen receptors (ERs) to reveal mitochondrial functions in the search for further research and therapeutic strategies for AD pharmacotherapy. Understanding and addressing the intricate interactions of mitochondrial dysfunction and ERs potentially pave the way for more effective approaches to AD therapy.

Rationality of the ethanol precipitation process in modern preparation production of Zishui-Qinggan decoction evaluated by integrating UPLC-QTOF-MS/MS-based chemical profiling/serum pharmacochemistry and network pharmacology

INTRODUCTION

Zishui-Qinggan decoction (ZQD) is a classical traditional Chinese medicine formula (TCMF) for alleviating menopausal symptoms (MPS) induced by endocrine therapy in breast cancer patients. In the production of TCMF modern preparations, ethanol precipitation (EP) is a commonly but not fully verified refining process.

OBJECTIVES

Chemical profiling/serum pharmacochemistry and network pharmacology approaches were integrated for exploring the rationality of the EP process in the production of ZQD modern preparations.

MATERIAL AND METHODS

Ultra-performance liquid chromatography-quadrupole time-of-flight tandem mass spectrometry (UPLC-QTOF-MS/MS) was applied to identify the chemical profiles and absorbed components of ZQD. Network pharmacology was used to identify targets and pathways related to MPS-relieving efficacy.

RESULTS

The chemicals of ZQDs without/with EP process (referred to as ZQD-W and ZQD-W-P, respectively) were qualitatively similar with 89 and 87 components identified, respectively, but their relative contents were different; 51 components were detectable in the serum of rats orally administered with ZQD-W, whereas only 19 were detected in that administered with ZQD-W-P. Key targets, such as AKT1, and pathways, such as the PI3K-Akt signalling pathway, affected by ZQD-W and ZQD-W-P were similar, while the neuroactive ligand-receptor interaction pathway among others and the MAPK signalling pathway among others were specific pathways affected by ZQD-W and ZQD-W-P, respectively. The specifically absorbed components of ZQD-W could combine its specific key targets.

CONCLUSION

The EP process quantitatively altered the chemical profiles of ZQD, subsequently affected the absorbed components of ZQD, and then affected the key targets and pathways of ZQD for relieving MPS. The EP process might result in variation of the MPS-relieving efficacy of ZQD, which deserves further in vivo verification.

Transformation or replacement - Effects of hormone therapy on cardiovascular risk

Hormone therapy (HT) is important and frequently used both regarding replacement therapy (HRT) and gender affirming therapy (GAHT). While HRT has been effective in addressing symptoms related to hormone shortage, several side effects have been described. In this context, there are some studies that show increased cardiovascular risk. However, there are also studies reporting protective aspects of HT. Nevertheless, the exact impact of HT on cardiovascular risk and the underlying mechanisms remain poorly understood. This article explores the relationship between diverse types of HT and cardiovascular risk, focusing on mechanistic insights of the underlying hormones on platelet and leukocyte function as well as on effects on endothelial and adipose tissue cells.

Sex differences in vascular endothelial cells

Endothelial cells are important constituents of blood vessels and play a critical role in vascular homeostasis. They do not only control the exchanges between the blood and the surrounding tissues, but are also essential in regulating blood flow, modulating immune-cell trafficking and controlling vascular growth and repair. Endothelial dysfunction leads to cardiovascular diseases and is characterized by deficiency in secretion of vasodilator molecules, elevated reactive oxygen species (ROS), expression of adhesion molecules and excretion of proinflammatory cytokines. The sex hormones, estrogens, androgens and progestogens, regulate endothelial functions. Because cardiovascular disease risk increases after menopause, it is believed that female hormones, estrogens and progestogens promote endothelial cell health and function whereas androgens, the male hormones, might be detrimental. However, as illustrated in the present review, the picture might not be that simple. In addition, sex influences endothelial cell physiology independently of sex hormones but at genetic level.

The G protein-coupled oestrogen receptor GPER in health and disease: an update

Oestrogens and their receptors contribute broadly to physiology and diseases. In premenopausal women, endogenous oestrogens protect against cardiovascular, metabolic and neurological diseases and are involved in hormone-sensitive cancers such as breast cancer. Oestrogens and oestrogen mimetics mediate their effects via the cytosolic and nuclear receptors oestrogen receptor-α (ERα) and oestrogen receptor-β (ERβ) and membrane subpopulations as well as the 7-transmembrane G protein-coupled oestrogen receptor (GPER). GPER, which dates back more than 450 million years in evolution, mediates both rapid signalling and transcriptional regulation. Oestrogen mimetics (such as phytooestrogens and xenooestrogens including endocrine disruptors) and licensed drugs such as selective oestrogen receptor modulators (SERMs) and downregulators (SERDs) also modulate oestrogen receptor activity in both health and disease. Following up on our previous Review of 2011, we herein summarize the progress made in the field of GPER research over the past decade. We will review molecular, cellular and pharmacological aspects of GPER signalling and function, its contribution to physiology, health and disease, and the potential of GPER to serve as a therapeutic target and prognostic indicator of numerous diseases. We also discuss the first clinical trial evaluating a GPER-selective drug and the opportunity of repurposing licensed drugs for the targeting of GPER in clinical medicine.

Evidence of Nitric Oxide Impairment During Hypertensive Pregnancies

Hypertensive disorders of pregnancy complicate up to 10% of pregnancies worldwide, and they can be classified into (1) gestational hypertension, (2) preeclampsia, (3) chronic hypertension and (4) chronic hypertension with preeclampsia. Nitric oxide (NO) plays an essential role in the haemodynamic adaptations observed during pregnancy. It has been shown that the nitric oxide pathway's dysfunction during pregnancy is associated with placental- and vascular-related diseases such as hypertensive disorders of pregnancy. This review aims to present a brief definition of hypertensive disorders of pregnancy and physiological maternal cardiovascular adaptations during pregnancy. We also detail how NO signalling is altered in the (a) systemic vasculature, (b) uterine artery/spiral arteries, (c) implantation and (d) placenta of hypertensive disorders during pregnancy. We conclude by summarizing the anti-hypertensive therapy of hypertensive disorders of pregnancy as a specific management strategy.

Sample multiplexing for increasing throughput for quantification of estrogens in serum by LC-MS/MS

Estrogens are involved in many physiological processes in vivo. The accurate and rapid quantification of estrogens is required for the diagnosis and prognosis of estrogen-related diseases. To achieve high-volume assays, we developed and validated a sample-multiplexing liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the quantification of serum estrogens including estrone (E1), estradiol (E2), and estriol (E3). A total of 100 μL serum samples were extracted using ethyl acetate. After derivatization with either dansyl chloride or pyridine-3-sulfonyl chloride, derivatized samples were combined. Then we performed the second liquid-liquid extraction using hexane to purify the mixture. Finally, the reconstitution solutions were injected into LC-MS/MS. In addition, the proposed LC-MS/MS method was validated according to FDA and CLSI guidelines. Within a single run (7 min), this sample-multiplexing LC-MS/MS method could simultaneously analyze E1, E2, and E3 in 2 serum samples. Meanwhile, the method demonstrated satisfactory analytical characteristics including accuracy (87.7-110.3%), linearity (2-1000 pg/mL, R² > 0.99), precision (intra-assay CV, 1.7-8.7%; inter-assay CV, 1.9-9.4%), and negligible interference and carry-over effect as well as acceptable matrix effect. In conclusion, this sample-multiplexing LC-MS/MS method has achieved a doubled-throughput assay for simultaneous quantification of E1, E2, and E3 without compromising analytical characteristics.

mPRα and PR co-operate in progesterone inhibition of endothelial cell focal adhesion

Progesterone causes vascular smooth muscle cell relaxation through membrane progesterone receptors (mPRs), which are members of the progestin and adipoQ receptor (PAQR) family, and nuclear PRs (nPRs). However, beneficial vascular effects of progesterone in preventing pre-atherosclerosis and the involvement of mPRs and nPRs remain unclear. The results show short- to long-term treatments with 100 nM progesterone (P4) and specific agonists for mPRs, OD 02-0, and nPRs, R5020, inhibited pre-atherosclerotic events in human umbilical vein endothelial cells (HUVECs), decreasing focal adhesion (FA) by monocytes, FA signaling, HUVEC migration and invasion, and vinculin expression. Progesterone and OD 02-0, but not R5020, inhibited phosphorylation of Src and focal adhesion kinase, critical kinases of FA signaling, within 20 min and migration and invasion of HUVECs and monocyte adhesion after 3 h. These inhibitory P4 and 02-0 effects were attenuated with MAP kinase and Pi3k inhibitors, indicating involvement of these kinases in this mPR-mediated action. However, after 16 h, OD 02-0 was no longer effective in inhibiting FA signaling, while both progesterone and R5020 decreased the activity of the two kinases. Knockdown of receptor expression with siRNA confirmed that mPRα mediates short-term and nPR long-term inhibitory effects of progesterone on FA signaling. Thus, progesterone inhibition of FA signaling and pre-atherosclerosis is coordinated through mPRα and nPRs.

Functions of Membrane Progesterone Receptors (mPRs, PAQRs) in Nonreproductive Tissues

Gender differences in a wide variety of physiological parameters have implicated the ovarian hormones, estrogens and progesterone, in the regulation of numerous nonreproductive tissue functions. Rapid, nongenomic (nonclassical) progesterone actions mediated by membrane progesterone receptors (mPRs), which belong to the progestin and adipoQ receptor family, have been extensively investigated in reproductive and nonreproductive tissues since their discovery in fish ovaries 20 years ago. The 5 mPR subtypes (α, β, γ, δ, ε) are widely distributed in vertebrate tissues and are often expressed in the same cells as the nuclear progesterone receptor (PR) and progesterone receptor membrane component 1, thereby complicating investigations of mPR-specific functions. Nevertheless, mPR-mediated progesterone actions have been identified in a wide range of reproductive and nonreproductive tissues and distinguished from nuclear PR-mediated ones by knockdown of these receptors with siRNA in combination with a pharmacological approach using mPR- and PR-specific agonists. There are several recent reviews on the roles of the mPRs in vertebrate reproduction and cancer, but there have been no comprehensive assessments of mPR functions in nonreproductive tissues. Therefore, this article briefly reviews mPR functions in a broad range of nonreproductive tissues. The evidence that mPRs mediate progesterone and progestogen effects on neuroprotection, lordosis behavior, respiratory control of apnea, olfactory responses to pheromones, peripheral nerve regeneration, regulation of prolactin secretion in prolactinoma, immune functions, and protective functions in vascular endothelial and smooth muscle cells is critically reviewed. The ubiquitous expression of mPRs in vertebrate tissues suggests mPRs regulate many additional nonreproductive functions that remain to be identified.

Estradiol and Estrogen-like Alternative Therapies in Use: The Importance of the Selective and Non-Classical Actions

Estrogen is one of the most important female sex hormones, and is indispensable for reproduction. However, its role is much wider. Among others, due to its neuroprotective effects, estrogen protects the brain against dementia and complications of traumatic injury. Previously, it was used mainly as a therapeutic option for influencing the menstrual cycle and treating menopausal symptoms. Unfortunately, hormone replacement therapy might be associated with detrimental side effects, such as increased risk of stroke and breast cancer, raising concerns about its safety. Thus, tissue-selective and non-classical estrogen analogues have become the focus of interest. Here, we review the current knowledge about estrogen effects in a broader sense, and the possibility of using selective estrogen-receptor modulators (SERMs), selective estrogen-receptor downregulators (SERDs), phytoestrogens, and activators of non-genomic estrogen-like signaling (ANGELS) molecules as treatment.

In search of pulmonary hypertension treatments: Effect of 17β-estradiol on PGI2 pathway in human pulmonary artery

INTRODUCTION

Prostacyclin (PGI₂) is synthetized by PGI₂ synthase (PGIS) and induces vasorelaxation via activation of cyclic AMP (cAMP) generating IP-receptor. Several components of the PGI₂ signaling pathway are reduced in patients with pulmonary hypertension (PH).

AIM

To study the effect of 17β-estradiol (E2) on the PGI₂ signaling pathway in human pulmonary arteries (HPA) and in their smooth muscle cells (hPASMC) derived from Group-3 PH and non-PH patients.

METHODS

Following E2-treatments of isolated HPA and cultured hPASMC, we measured: 6-keto-Prostaglandin F_1α (PGI₂ stable metabolite) by ELISA, PGIS and IP protein levels by Western blot and HPA vasorelaxations with an organ bath system.

RESULTS

Incubation with E2 (24/48 h, doses ≥ 10 nM) significantly increased the expression of PGIS in hPASMC derived from both PH (65-98%) and non-PH (21-33%) patients, whereas incubation with E2 (2 h, 0.1 and 1 µM) increased 6-keto-PGF_1α production in HPA from Group-3 PH patients only, and did not affect 6-keto-PGF_1α production in hPASMC from either non-PH or Group-3 PH patients. Increases in IP receptor expression were observed following 10 mM E2-treatment of hPASMC from non-PH (33% after 48 h) and Group-3 PH (23% after 24 h) patient lungs. Finally, preincubation with 100 nM E2 significantly increased arachidonic acid-induced vasorelaxation of HPA from non-PH patient lungs but not of HPA from Group-3 PH patient lungs.

CONCLUSION

E2-treatment may help to restore the PGI₂-pathway in Group-3 PH.

Membrane progesterone receptor α (mPRα/PAQR7) promotes migration, proliferation and BDNF release in human Schwann cell-like differentiated adipose stem cells

Membrane progesterone receptors (mPRs) were recently found to be present and active in Schwann cells, where they have a potentially pro-regenerative activity. In this study, we investigated the role of mPRs in human adipose stem cells (ASC) differentiated into Schwann cell-like cells (SCL-ASC), which represent a promising alternative to Schwann cells for peripheral nerve regeneration. Our findings show that mPRs are present both in undifferentiated and differentiated ASC, and that the differentiation protocol upregulates mPR expression. Activation of mPRα promoted cell migration and differentiation in SCL-ASC, alongside with changes in cell morphology and mPRα localization. Moreover, it increased the expression and release of BDNF, a neurotrophin with pro-regenerative activity. Further analysis showed that Src and PI3K-Akt signaling pathways are involved in mPRα activity in SCL-ASC. These findings suggest that mPRα could play a pro-regenerative role in SCL-ASC and may be a promising target for the promotion of peripheral nerve regeneration.

Involvement of sarco/endoplasmic reticulum Ca2+-ATPase (SERCA) in mPRα (PAQR7)-mediated progesterone induction of vascular smooth muscle relaxation

Progesterone acts directly on vascular smooth muscle cells (VSMCs) through activation of membrane progesterone receptor α (mPRα)-dependent signaling to rapidly decrease cytosolic Ca²⁺ concentrations and induce muscle relaxation. However, it is not known whether this progesterone action involves uptake of Ca²⁺ by the sarco/endoplasmic reticulum (SR) and increased sarco/endoplasmic reticulum Ca²⁺-ATPase (SERCA) activity. The present results show that treatment of cultured human VSMCs with progesterone and the selective mPR agonist Org OD-02-0 (OD 02-0) but not with the nuclear PR agonist R5020 increased SERCA protein expression, which was blocked by knockdown of mPRα with siRNA. Moreover, treatments with progesterone and OD 02-0, but not with R5020, increased phospholamban (PLB) phosphorylation, which would result in disinhibition of SERCA function. Progesterone and OD 02-0 significantly increased Ca²⁺ levels in the SR and caused VSMC relaxation. These effects were blocked by pretreatment with cyclopiazonic acid (CPA), a SERCA inhibitor, and by knockdown of SERCA2 with siRNA, suggesting that SERCA2 plays a critical role in progesterone induction of VSMC relaxation. Treatment with inhibitors of inhibitory G proteins (Gi, NF023), MAP kinase (AZD 6244), Akt/Pi3k (wortmannin), and a Rho activator (calpeptin) blocked the progesterone- and OD 02-0-induced increase in Ca²⁺ levels in the SR and SERCA expressions. These results suggest that the rapid effects of progesterone on cytosolic Ca²⁺ levels and relaxation of VSMCs through mPRα involve regulation of the functions of SERCA2 and PLB through Gi, MAP kinase, and Akt signaling pathways and downregulation of RhoA activity.NEW & NOTEWORTHY The rapid effects of progesterone on cytosolic Ca²⁺ levels and relaxation of VSMCs through mPRα involve regulation of the functions of SERCA2 and PLB through Gi, MAP kinase, and Akt signaling pathways and downregulation of RhoA activity.

Arginase inhibition by (-)-Epicatechin reverses endothelial cell aging

Endothelial dysfunction (EnD) occurs with aging and endothelial nitric oxide (NO) production by NO synthase (NOS) can be impaired. Low NO levels have been linked to increased arginase (Ar) activity as Ar competes with NOS for L-arginine. The inhibition of Ar activity can reverse EnD and (-)-epicatechin (Epi) inhibits myocardial Ar activity. In this study, through in silico modeling we demonstrate that Epi interacts with Ar similarly to its inhibitor Norvaline (Norv). Using in vitro and in vivo models of aging, we examined Epi and Norv-inhibition of Ar activity and its endothelium-protective effects. Bovine coronary artery endothelial cells (BCAEC) were treated with Norv (10 μM), Epi (1 μM) or the combination (Epi + Norv) for 48 h. Ar activity increased in aged BCAEC, with decreased NO generation. Treatment decreased Ar activity to levels seen in young cells. Epi and Epi + Norv decreased nitrosylated Ar levels by ~25% in aged cells with lower oxidative stress (~25%) (dihydroethidium) levels. In aged cells, Epi and Epi + Norv restored the eNOS monomer/dimer ratio, protein expression levels and NO production to those of young cells. Furthermore, using 18 month old rats 15 days of treatment with either Epi (1 mg/kg), Norv (10 mg/kg) or combo, decreased hypertension and improved aorta vasorelaxation to acetylcholine, blood NO levels and tetra/dihydribiopterin ratios in cultured rat aortic endothelial cells. In conclusion, results provide evidence that inhibiting Ar with Epi reverses aged-related loss of eNOS function and improves vascular function through the modulation of Ar and eNOS protein levels and activity.

A hypertension patient-derived iPSC model demonstrates a role for G protein-coupled estrogen receptor in hypertension risk and development

Hypertension (HTN) is a polyfactorial disease that can manifest severe cardiovascular pathologies such as heart failure or stroke. Genome-wide association studies (GWAS) of HTN indicate that single-nucleotide polymorphisms (SNPs) contribute to increased risk for HTN and resistance to some HTN drug regimens (Hiltunen TP et al., J Am Heart Assoc 4: e001521, 2015; Le MT et al., PLoS One 8: e52062, 2013; McDonough CW et al., J Hypertens 31: 698-704, 2013; Vandell AG et al., Hypertension 60: 957-964, 2012). However, cellular mechanistic insights of such SNPs remain largely unknown. Using a bank of induced pluripotent stem cells (iPSCs) derived from patients with HTN and CRISPR/Cas9-mediated gene-editing approach, we investigated the effects of a female HTN risk-associated SNP (rs1154431) of the G protein-coupled estrogen receptor (GPER) (Bassuk SS, Manson JE., Clin Chem 60: 68-77, 2014) in vascular endothelial cells. Although GPER1 deletion reduced endothelial nitric oxide synthase (eNOS) activation in iPSC-derived endothelial cells (iECs), the polymorphism itself did not significantly affect eNOS and NO production in a comparison of isogenic hemizygous iECs expressing either normal (P16) or HTN-associated (L16) GPER. Interestingly, we demonstrate for the first time that GPER plays a role in regulation of adhesion molecule expression and monocyte adhesion to iECs. Moreover, the L16 iECs had higher expression of inflammation genes than P16 iECs, implying that the risk variant may affect carrier individuals through increased inflammatory activity. This study further indicates that iPSCs are a useful platform for exploring mechanistic insights underlying hypertension GWAS endeavors.

Effects of progesterone treatment on endothelium-dependent coronary relaxation in ovariectomized rats

AIM

Although progesterone (P4) has a beneficial effect on the cardiovascular system, P4 actions on the coronary bed have not yet been fully elucidated. This study evaluated the effect of progesterone treatment on endothelium-dependent coronary vascular reactivity in Wistar rats.

MAIN METHODS

Eight-week-old adult rats were divided into Sham, Ovariectomized (OVX), Ovariectomized and progesterone treated (OVX P4). The OVX P4 group received daily doses of progesterone (2 mg/kg/day). Vascular reactivity was assessed by a modified Langendorff technique. The intensity of eNOS, Akt, and gp91phox protein expression was quantified by Western blotting. Superoxide anion (O₂^●-) and hydrogen peroxide (H₂O₂) production was measured by dihydroethidium and 2',7'-dichlorofluorescein, respectively.

KEY FINDINGS

Treatment with P4 was able to prevent the reduction in baseline coronary perfusion pressure induced by ovariectomy. We observed that endothelium-dependent coronary vasodilation was reduced in the OVX group and potentiated in the OVX P4 group. Following the inhibition of the nitric oxide (NO) pathway, the bradykinin-induced relaxing response was potentiated in the OVX P4 group. With regard to the combined inhibition of NO and prostanoids pathways, the OVX P4 group showed a greater relaxing response, similar to what was found upon individual inhibition of NO. After the combined inhibition of NO, prostanoids and epoxyeicosatrienoic acids' pathways, the vasodilatory response induced by BK was abolished in all groups.

SIGNIFICANCE

Treatment with P4 prevented oxidative stress induced by ovariectomy. These results suggest that progesterone has a beneficial action on the coronary vascular bed.

Influence of Estrogens on Uterine Vascular Adaptation in Normal and Preeclamptic Pregnancies

During pregnancy, the maternal cardiovascular system undergoes significant changes, including increased heart rate, cardiac output, plasma volume, and uteroplacental blood flow (UPBF) that are required for a successful pregnancy outcome. The increased UPBF is secondary to profound circumferential growth that extends from the downstream small spiral arteries to the upstream conduit main uterine artery. Although some of the mechanisms underlying uterine vascular remodeling are, in part, known, the factors that drive the remodeling are less clear. That higher circulating levels of estrogens are positively correlated with gestational uterine vascular remodeling suggests their involvement in this process. Estrogens binding to the estrogen receptors expressed in cytotrophoblast cells and in the uterine artery wall stimulate an outward hypertrophic remodeling of uterine vasculature. In preeclampsia, generally lower concentrations of estrogens limit the proper uterine remodeling, thereby reducing UPBF increases and restricting the growth of the fetus. This review aims to report estrogenic regulation of the maternal uterine circulatory adaptation in physiological and pathological pregnancy that favors vasodilation, and to consider the underlying molecular mechanisms by which estrogens regulate uteroplacental hemodynamics.

Protein kinase inhibitors infused intraventricularly or into the ventromedial hypothalamus block short latency facilitation of lordosis by oestradiol

An injection of unesterified oestradiol (E₂ ) facilitates receptive behaviour in E₂ benzoate (EB)-primed, ovariectomised female rats when it is administered i.c.v. or systemically. The present study tested the hypothesis that inhibitors of protein kinase A (PKA), protein kinase G (PKG) or the Src/mitogen-activated protein kinase (MAPK) complex interfere with E₂ facilitation of receptive behaviour. In Experiment 1, lordosis induced by i.c.v. infusion of E₂ was significantly reduced by i.c.v. administration of Rp-cAMPS, a PKA inhibitor, KT5823, a PKG inhibitor, and PP2 and PD98059, Src and MAPK inhibitors, respectively, between 30 and 240 minutes after infusion. In Experiment 2, we determined whether the ventromedial hypothalamus (VMH) is one of the neural sites at which those intracellular pathways participate in lordosis behaviour induced by E₂ . Administration of each of the four protein kinase inhibitors into the VMH blocked facilitation of lordosis induced by infusion of E₂ also into the VMH. These data support the hypothesis that activation of several protein kinase pathways is involved in the facilitation of lordosis by E₂ in EB-primed rats.

Nitric oxide activation by progesterone suppresses ATP-induced ciliary activity in oviductal ciliated cells

Ciliary beat frequency (CBF) regulates the oviductal transport of oocytes and embryos, which are important components of the reproductive process. Local release of ATP transiently increases CBF by increasing [Ca2+]i. Ovarian hormones also regulate ciliary activity and oviductal transport. Progesterone (P4) induces nitric oxide (NO) production and high P4 concentrations induce ciliary dysfunction. However, the mechanism by which P4 affects CBF has not been elucidated. To evaluate the role of P4 in NO production and its effect on ATP-induced increases in CBF, we measured CBF, NO concentrations and [Ca2+]i in cultures of oviductal ciliated cells treated with P4 or NO signalling-related molecules. ATP induced a [Ca2+]i peak, followed by an increase in NO concentrations that were temporally correlated with the decreased phase of the transiently increased CBF. Furthermore, P4 increased the expression of nitric oxide synthases (iNOS and nNOS) and reduced the ATP-induced increase in CBF via a mechanism that involves the NO signalling pathway. These results have improved our knowledge about intracellular messengers controlling CBF and showed that NO attenuates oviduct cell functions. Furthermore, we showed that P4 regulates neurotransmitter (ATP) actions on CBF via the NO pathway, which could explain pathologies where oviductal transport is altered and fertility decreased.

Progesterone induces relaxation of human umbilical cord vascular smooth muscle cells through mPRα (PAQR7)

Progesterone effects on vascular smooth muscle cell (VSMC) relaxation and the mechanism were investigated in cultured human umbilical vein VSMCs. Membrane progesterone receptors mPRα, mPRβ, and mPRγ were highly expressed in VSMCs, whereas nuclear progesterone receptor (nPR) had low expression. Progesterone (20 nM) and 02-0 (mPR-selective agonist), but not R5020 (nPR agonist), induced muscle relaxation in both a VSMC collagen gel disk contraction assay and an endothelium-denuded human umbilical artery ring tension assay. Progesterone and 02-0 increased ERK and Akt phosphorylation and decreased cAMP levels. These effects were blocked by preincubation with pertussis toxin. Progestin-induced muscle relaxation was blocked by pretreatment with mPRα, but not nPR, siRNAs, and by co-treatment with 8-Br-cAMP, AZD6244 (MAP kinase inhibitor), and wortmannin (PI3K inhibitor). Progestins reduced myosin light chain phosphorylation which was blocked with AZD6244 and wortmannin. These results demonstrate progesterone directly relaxes human VSMCs through mPRα/Gi and MAP kinase/ERK-, Akt/PI3K-, and cAMP-dependent pathways.

Estrogens regulate life and death in mitochondria

Estrogens coordinate and integrate cellular metabolism and mitochondrial activities by direct and indirect mechanisms mediated by differential expression and localization of estrogen receptors (ER) in a cell-specific manner. Estrogens regulate transcription and cell signaling pathways that converge to stimulate mitochondrial function- including mitochondrial bioenergetics, mitochondrial fusion and fission, calcium homeostasis, and antioxidant defense against free radicals. Estrogens regulate nuclear gene transcription by binding and activating the classical genomic estrogen receptors α and β (ERα and ERβ) and by activating plasma membrane-associated mERα, mERβ, and G-protein coupled ER (GPER, GPER1). Localization of ERα and ERβ within mitochondria and in the mitochondrial membrane provides additional mechanisms of regulation. Here we review the mechanisms of rapid and longer-term effects of estrogens and selective ER modulators (SERMs, e.g., tamoxifen (TAM)) on mitochondrial biogenesis, morphology, and function including regulation of Nuclear Respiratory Factor-1 (NRF-1, NRF1) transcription. NRF-1 is a nuclear transcription factor that promotes transcription of mitochondrial transcription factor TFAM (mtDNA maintenance factorFA) which then regulates mtDNA-encoded genes. The nuclear effects of estrogens on gene expression directly controlling mitochondrial biogenesis, oxygen consumption, mtDNA transcription, and apoptosis are reviewed.

MicroRNA-199a-5p aggravates primary hypertension by damaging vascular endothelial cells through inhibition of autophagy and promotion of apoptosis

The present study investigated the expression of microRNA (miRNA or miR)-199a-5p in the peripheral blood of patients with primary hypertension, and examined its mechanism of action in vascular endothelial cell injury induced by hypertension. A total of 57 patients with primary hypertension, who were treated at the Affiliated Hospital of Qingdao University (Qingdao, China) between December 2014 and November 2015 were included in the present study. Peripheral blood was collected from all patients. The expression of miR-199a-5p was measured using reverse-transcription quantitative polymerase chain reaction analysis. Human umbilical vein endothelial cells (HUVECs) were divided into negative control, miR-199a-5p mimics and rescue (co-transfected with miR-199a-5p mimics and inhibitor) groups. After transfection, the proliferation and apoptosis of HUVECs were evaluated by a Cell Counting Kit-8 assay, a bromodeoxyuridine incorporation assay and flow cytometry. Western blot analysis was used to determine the expression of proteins involved in autophagy-associated and adenosine monophosphate kinase (AMPK)/unc-51 like autophagy activating kinase 1 (ULK1) signaling pathways. Laser scanning confocal microscopy and electron microscopy were used to observe the autophagy of HUVECs. The expression of miR-199a-5p was elevated in peripheral blood of patients with hypertension, and was correlated with the progression of hypertension. Overexpression of miR-199a-5p inhibited the proliferation and promoted the apoptosis of HUVECs. Upon expression of miR-199a-5p, the transition between microtubule-associated proteins 1A/1B light chain 3B (LC3B)I and LC3BII proteins was inhibited, the expression of p62 protein was upregulated. In addition, miR-199a-5p decreased the numbers of autophagosomes and autolysosomes in HUVECs. The present study demonstrated that expression of miR-199a-5p is positively correlated with the severity of hypertension. Expression of miR-199a-5p aggravated vascular endothelial injury by inhibiting autophagy and promoting the apoptosis of HUVECs via downregulation of the AMPK/ULK1 signaling pathway.

Membrane progesterone receptors β and γ have potential as prognostic biomarkers of endometrial cancer

Endometrial cancer (EC) is one of the most common malignancies in women worldwide. EC is linked to chronic exposure to estrogens that is unopposed by protective effects of progesterone. Progesterone modulates gene expression via classical nuclear receptors, and has rapid effects via the less characterized membrane-bound progesterone receptors (mPRs) of the progestin and adipoQ receptor (PAQR) family. The presence of mPRs in EC has not been investigated to date. The aims of this study were to examine PAQR7, PAQR8 and PAQR5, which encode for mPRα, mPRβ and mPRγ, respectively, for their expression and localization in EC tissue and adjacent control endometrium. Our results reveal decreased expression of PAQR7 and PAQR8, and unaltered expression of PAQR5 in EC versus control tissue. Expression of PAQR5 was decreased in EC with higher FIGO stage versus stage IA. Immunohistochemistry revealed lower levels of mPRα and mPRβ, but higher levels of mPRγ, in EC versus control tissue. There was greater decrease in mPRβ levels in tumors with lymphovascular invasion. The analysis of the expression data associates higher PAQR5 mRNA and mPRβ protein levels with favorable patient prognosis. Immunohistochemistry showed diverse localizations of mPRs in control and cancer endometrium. In control endometrium, mPRα and mPRβ were localized mostly at the cell membranes, while mPRγ was localized in the cytoplasm and/or nucleus. In cancer endometrium, mPRα and mPRβ were detected at the cell membrane or in the cytoplasm, or both, while mPRγ was only localized in the cytoplasm. Taken together, these results imply that mPRs are involved in EC pathogenesis through effects on the development or progression of cancer. The potential role of mPRβ and mPRγ as prognostic biomarkers needs to be further assessed on a larger number of samples.

Developmental programming of vascular dysfunction by prenatal and postnatal zinc deficiency in male and female rats

Micronutrient malnutrition during intrauterine and postnatal growth may program cardiovascular diseases in adulthood. We examined whether moderate zinc restriction in male and female rats throughout fetal life, lactation and/or postweaning growth induces alterations that can predispose to the onset of vascular dysfunction in adulthood. Female Wistar rats were fed low- or control zinc diets from pregnancy to offspring weaning. After weaning, offspring were fed either a low- or a control zinc diet until 81 days. We evaluated systolic blood pressure (SBP), thoracic aorta morphology, nitric oxide (NO) system and vascular reactivity in 6- and/or 81-day-old offspring. At day 6, zinc-deficient male and female offspring showed a decrease in aortic NO synthase (NOS) activity accompanied by an increase in oxidative stress. Zinc-deficient 81-day-old male rats exhibited an increase in collagen deposition in tunica media, as well as lower activity of endothelial NOS (eNOS) that could not be reversed with an adequate zinc diet during postweaning life. Zinc deficiency programmed a reduction in eNOS protein expression and higher SBP only in males. Adult zinc-deficient rats of both sexes showed reduced vasodilator response dependent on eNOS activity and impaired aortic vasoconstrictor response to angiotensin-II associated with alterations in intracellular calcium mobilization. Female rats were less sensitive to the effects of zinc deficiency and exhibited higher eNOS activity and/or expression than males, without alterations in SBP or aortic histology. This work strengthens the importance of a balanced intake of micronutrients during perinatal growth to ensure adequate vascular function in adult life.

Role of GPER in estrogen-dependent nitric oxide formation and vasodilation

Estrogens are potent regulators of vasomotor tone, yet underlying receptor- and ligand-specific signaling pathways remain poorly characterized. The primary physiological estrogen 17β-estradiol (E2), a non-selective agonist of classical nuclear estrogen receptors (ERα and ERβ) as well as the G protein-coupled estrogen receptor (GPER), stimulates formation of the vasodilator nitric oxide (NO) in endothelial cells. Here, we studied the contribution of GPER signaling in E2-dependent activation of endothelial NO formation and subsequent vasodilation. Employing E2 and the GPER-selective agonist G-1, we investigated eNOS phosphorylation and NO formation in human endothelial cells, and endothelium-dependent vasodilation in the aortae of wild-type and Gper-deficient mice. Both E2 and G-1 induced phosphorylation of eNOS at the activation site Ser1177 to similar extents. Endothelial NO production to E2 was comparable to that of G-1, and was substantially reduced after pharmacological inhibition of GPER. Similarly, the clinically used ER-targeting drugs 4OH-tamoxifen, raloxifene, and ICI182,780 (faslodex, fulvestrant™) induced NO formation in part via GPER. We identified c-Src, EGFR, PI3K and ERK signaling pathways to be involved in GPER-dependent NO formation. In line with activation of NO formation in cells, E2 and G-1 induced equally potent vasodilation in the aorta of wild-type mice. Gper deletion completely abrogated the vasodilator response to G-1, while reducing the response to E2 by ∼50%. These findings indicate that a substantial portion of E2-induced endothelium-dependent vasodilation and NO formation is mediated by GPER. Thus, selective targeting of vascular GPER may be a suitable approach to activate the endothelial NO pathway, possibly leading to reduced vasomotor tone and inhibition of atherosclerotic vascular disease.

New roles for neuronal estrogen receptors

Estrogens encompass steroid hormones which display physiological roles not only in the female reproductive system but also in other organ systems of non-reproductive controls, including the peripheral and central nervous systems. Traditionally, estrogen signals in neurons through a "genomic pathway": binding to estrogen receptors (ERs) which then interact with nuclear estrogen response elements to initiate transcription. This effect is usually delayed at onset (within several hours to days) and prolonged in duration. In addition to these classical ERs, recent data suggest that other ERs function through pregenomic signaling pathways. Estrogen's pregenomic pathways cause intracellular changes within seconds to minutes and go through a novel, 7-transmembrane spanning G protein-coupled receptor (GPER, formerly known as GPR30). In this review, we will briefly cover the cellular and molecular mechanisms of GPER and then discuss newly discovered roles of GPER in cognition, depression, homeostasis, pain processing, and other associated neuronal functions.