Application Of 17β-estradiol Research Articles

Removal of Soluble ACE2 in VeroE6 Cells by 17β-Estradiol Reduces SARS-CoV-2 Infectivity.

Women are less susceptible than men to coronavirus disease 2019 (COVID-19), which might be due to the female steroid hormone 17β-estradiol. We hypothesized that 17β-estradiol removes the soluble portion of angiotensin-converting enzyme 2 (sACE2) to which severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) binds in host cells and that sACE2 then binds to the virus, thereby reducing the infectivity. In the present study, VeroE6/serine protease 2 transmembrane protein (TMPRSS2) cells were infected with pseudo SARS-CoV-2 viruses and used as our model system. This infectivity was reduced by the application of 17β-estradiol. After applying 17β-estradiol to the VeroE6/TMPRSS2 cells, we used a sandwich enzyme-linked immunosorbent assay (ELISA) to measure the sACE2 concentration in the culture medium. Our findings revealed that 17β-estradiol removes sACE2 from VeroE6/TMPRSS2 cells. Furthermore, the pseudo SARS-CoV-2 viruses were incubated in culture medium with ACE2 collected from 17β-estradiol-treated VeroE6/TMPRSS2 cells, and the viruses were measured with an ultrasensitive ELISA using anti-spike protein antibodies. The amount of spike proteins decreased according to the concentration of 17β-estradiol applied. These results clearly demonstrated that the soluble portion of ACE2, which was removed from 17β-estradiol-treated VeroE6/TMPRSS2 cells, bound to the spike proteins of SARS-CoV-2, thereby reducing COVID-19 infectivity.

The Interaction Between NF-κB and Estrogen in Alzheimer's Disease.

Post-menopausal women are at a higher risk of developing Alzheimer's disease (AD) than males. The higher rates of AD in women are associated with the sharp decline in the estrogen levels after menopause. Estrogen has been shown to downregulate inflammatory cytokines in the central nervous system (CNS), which has a neuroprotective role against neurodegenerative diseases including AD. Sustained neuroinflammation is associated with neurodegeneration and contributes to AD. Nuclear factor kappa-B (NF-κB) is a transcription factor involved with the modulation of inflammation and interacts with estrogen to influence the progression of AD. Application of 17β-estradiol (E2) has been shown to inhibit NF-κB, thereby reducing transcription of NF-κB target genes. Despite accumulating evidence showing that estrogens have beneficial effects in pre-clinical AD studies, there are mixed results with hormone replacement therapy in clinical trials. Furthering our understanding of how NF-κB interacts with estrogen and alters the progression of neurodegenerative disorders including AD, should be beneficial and result in the development of novel therapeutics.

17β-Estradiol activates Cl− channels via the estrogen receptor α pathway in human thyroid cells

ABSTRACT Estradiol regulates thyroid function, and chloride channels are involved in the regulation of thyroid function. However, little is known about the role of chloride channels in the regulation of thyroid functions by estrogen. In this study, the effects of estrogen on chloride channel activities in human thyroid Nthy-ori3-1 cells were therefore investigated using the whole cell patch-clamp technique. The results showed that the extracellular application of 17β-estradiol (E2) activated Cl− currents, which reversed at a potential close to Cl− equilibrium potential and showed remarkable outward rectification and an anion permeability of I− > Br− > Cl− > gluconate. The Cl− currents were inhibited by the chloride channel blockers, NPPB and tamoxifen. Quantitative Real-time PCR results demonstrated that ClC-3 expression was highest in ClC family member in Nthy-ori3-1 cells. The down-regulation of ClC-3 expression by ClC-3 siRNA inhibited E2-induced Cl− current. The Cl− current was blocked by the estrogen receptor antagonist, ICI 182780 (fulvestrant). Estrogen receptor alpha (ERα) and not estrogen receptor beta was the protein expressed in Nthy-ori3-1 cells, and the knockdown of ERα expression with ERα siRNA abolished E2-induced Cl− currents. Estradiol can promote the accumulation of ClC-3 in cell membrane. ERα and ClC-3 proteins were partially co-localized in the cell membrane of Nthy-ori3-1 cells after estrogen exposure. The results suggest that estrogen activates chloride channels via ERα in normal human thyroid cells, and ClC-3 proteins play a pivotal role in the activation of E2-induced Cl− current.

TRPV1-Estradiol Stereospecific Relationship Underlies Cell Survival in Oxidative Cell Death.

17β-estradiol is a neuronal survival factor against oxidative stress that triggers its protective effect even in the absence of classical estrogen receptors. The polymodal transient receptor potential vanilloid subtype 1 (TRPV1) channel has been proposed as a steroid receptor implied in tissue protection against oxidative damage. We show here that TRPV1 is sufficient condition for 17β-estradiol to enhance metabolic performance in injured cells. Specifically, in TRPV1 expressing cells, the application of 17β-estradiol within the first 3 h avoided H2O2-dependent mitochondrial depolarization and the activation of caspase 3/7 protecting against the irreversible damage triggered by H2O2. Furthermore, 17β-estradiol potentiates TRPV1 single channel activity associated with an increased open probability. This effect was not observed after the application of 17α-estradiol. We explored the TRPV1-Estrogen relationship also in primary culture of hippocampal-derived neurons and observed that 17β-estradiol cell protection against H2O2-induced damage was independent of estrogen receptors pathway activation, membrane started and stereospecific. These results support the role of TRPV1 as a 17β-estradiol-activated ionotropic membrane receptor coupling with mitochondrial function and cell survival.

A combinatorial modulation of synaptic plasticity in the rat medial amygdala by oxytocin, urocortin3 and estrogen

The medial nucleus of the amygdala (MeA) plays a pivotal role in a variety of mammalian social behaviors. Specifically, activity of the hypothalamic pro-social neuropeptide oxytocin in the MeA was shown to be crucial for social recognition memory. The MeA is also a hub of neuroendocrine activity and expresses a large number of receptors of neuropeptides and hormones. These include oxytocin receptor, estrogen receptor alpha and corticotropin-releasing factor (CRF) receptor type 2 (CRFR2). In a previous study we found that intracerebroventricular (ICV) oxytocin application to anesthetized rats promotes long-term depression (LTD) of the MeA response to electrical stimulation of its main sensory input, the accessory olfactory bulb (AOB). We also reported that this type of synaptic plasticity contributes to long-term social recognition memory. Here we used similar methodology to examine the possibility that various neuromodulators pose a combinatorial effect on synaptic plasticity in the MeA. We found that ICV administration of the CRF-related peptide urocortin3 fifteen minutes before oxytocin, caused long-term potentiation (LTP), via CRFR2 activation. Similarly, ICV administration of 17β-estradiol forty-five minutes before oxytocin induced LTP, which was blocked by an antagonist of the estrogen receptors alpha and beta. Notably, none of these two neuromodulators had any effect on its own, suggesting that they both turn the oxytocin-mediated synaptic plasticity from LTD to LTP. Finally, we found that application of 17β-estradiol, forty-five minutes before urocortin3 also caused LTP in the MeA response to AOB stimulation, even without oxytocin application. We suggest that the combinatorial modulation of the bidirectional synaptic plasticity in the AOB-MeA pathway by oxytocin, 17β-estradiol and urocotin-3 serves to modify social information processing according to the animal's internal state.

Complex effects of 17β-estradiol on mitochondrial function

Existing literature on estradiol indicates that it affects mitochondrial functions at low micromolar concentrations. Particularly blockade of the permeability transition pore (PTP) or modulation of the enzymatic activity of one or more complexes of the respiratory chain were suspicious. We prepared mitoplasts from rat liver mitochondria (RLM) to study by single-channel patch-clamp techniques the PTP, and from rat astrocytes to study the potassium BK-channel said to modulate the PTP. Additionally, we measured respiration of intact RLM. After application of 17β-estradiol (βE) our single-channel results reveal a transient increase of activity of both, the BK-channel and the PTP followed by their powerful inhibition. Respiration measurements demonstrate inhibition of the Ca2+-induced permeability transition, as well, though only at higher concentrations (≥30μM). At lower concentrations, we observed an increase of endogenous- and state 2-respiration. Furthermore, we show that βE diminishes the phosphorylating respiration supported by complex I-substrates (glutamate/malate) or by the complex II-substrate succinate. Taken together the results suggest that βE affects mitochondria by several modes, including partial inhibition of the activities of ion channels of the inner membrane and of respiration. This article is part of a Special Issue entitled: 17th European Bioenergetics Conference (EBEC 2012).

129 THE INFLUENCE OF RED CLOVER DERIVED ISOFLAVONES ON QUALITY OF LIFE IN POSTMENOPAUSAL WOMEN

Objectives: Purpose of this study is to present the beneficial effects of vaginal application of conjugated estrogen, for the treatment of vaginal atrophy and urethral caruncle at postmenopausal women. Materials and methods: For the purpose of this study we used 60 postmenopausal women aged between 55 and 70 years old with vaginal atrophy (12 among them had also urethral caruncle), who didn’t have menses for the last 2 years and their laboratory examinations showed high elevated gonadotrophines. We administered to the patients vaginally tablets of 17 β-estradiol every second day, for an at least 3 months period. Specific for the women with urethral caruncle, the pharmacist converted the same tablets to vaginal cream. Results: Vaginal application of 17β-estradiol improved statistically significant the symptoms of vaginal atrophy like vaginal dryness, pruritus, dyspareunia and urethral caruncle). Conclusions: Vaginal application of 17β-estradiol is an effective treatment for the symptoms of vaginal atrophy like vaginal dryness, pruritus, dyspareunia and improves the quality of sexual activity of postmenopausal women.

Estrogen modulation of peripheral pain signal transduction: involvement of P2X3 receptors

There is evidence that gonadal hormones may affect the perception of painful stimulation, although the underlying mechanisms remain unclear. This investigation was undertaken to determine whether the adenosine 5'-triphosphate (ATP) receptor subunit, P2X(3), is involved in the modulatory action of estrogen in peripheral pain signal transduction in dorsal root ganglion (DRG). The mechanical pain behavior test, real-time quantitative reverse transcription-polymerase chain reaction analysis, and Western blot methods were used to determine the mean relative concentrations and functions of P2X(3) receptors in DRG in sham, ovariectomized (OVX), and estradiol replacement (OVX+E(2)) female rats and in sham and orchiectomized male rats. The mechanical hyperalgesia appeared after ovariectomy, which was subsequently reversed after estradiol replacement, whereas it was not observed after orchiectomy in male rats. Plantar injection of 2'(3')-O-(2,4,6-trinitrophenyl) ATP (TNP-ATP), a P2X(3) and P2X(2/3) receptor antagonist, resulted in an increase of the pain threshold force in OVX rats while had no effect on sham rats. Furthermore, A-317491, a selective P2X(3)/P2X(2/3) receptor antagonist, significantly reversed the hyperalgesia of OVX rats. Injection of ATP into the plantars also caused a significant increase of the paw withdrawal duration in OVX rats compared with that seen in the sham group, which became substantially attenuated by TNP-ATP. P2X(3) receptors expressed in DRG were significantly increased in both mRNA and protein levels after ovariectomy and then reversed after estrogen replacement, while a similar increase was not observed after orchiectomy in male rats. Furthermore, P2X(3) mRNA was significantly decreased 24h after the application of 17β-estradiol in a concentration-dependent manner in cultured DRG neurons. ICI 182,780, an estrogen receptor antagonist, blocked the reduction in the protein level. These results suggest that the female gonadal hormone, 17β-estradiol, might participate in the control of peripheral pain signal transduction by modulating P2X(3) receptor-mediated events in primary sensory neurons, probably through genomic mechanisms.

17β-estradiol reduces expression of MMP-1, -3, and -13 in human primary articular chondrocytes from female patients cultured in a three dimensional alginate system

Clinical observations have suggested a relationship between osteoarthritis and a changed sex-hormone metabolism, especially in menopausal women. This study analyzes the effect of 17β-estradiol on expression of matrix metalloproteinases-1, -3, -13 (MMP-1, -3, -13) and tissue inhibitors of metalloproteinases-1, -2 (TIMP-1, -2) in articular chondrocytes. An imbalance of matrix metalloproteinases (MMPs) specialized on degradation of articular cartilage matrix over the respective inhibitors of these enzymes (TIMPs) that leads to matrix destruction was postulated in the pathogenesis of osteoarthritis. Primary human articular chondrocytes from patients of both genders were cultured in alginate beads at 5% O(2) to which 10(-11)M-10(-5)M 17β-estradiol had been added and analyzed by means of immunohistochemistry, immunocytochemistry and real-time RT-PCR. Since articular chondrocytes in vivo are adapted to a low oxygen tension, culture was performed at 5% O(2). Immunohistochemical staining in articular cartilage tissue from patients and immunocytochemical staining in articular chondrocytes cultured in alginate beads was positive for type II collagen, estrogen receptor α, MMP-1, and -13. It was negative for type I collagen, MMP-3, TIMP-1 and -2. Using real-time RT-PCR, it was demonstrated that physiological and supraphysiological doses of 17β-estradiol suppress mRNA levels of MMP-3 and -13 significantly in articular chondrocytes of female patients. A significant suppressing effect was also seen in MMP-1 mRNA after a high dose of 10(-5)M 17β-estradiol. Furthermore, high doses of this hormone led to tendentially lower TIMP-1 levels whereas the TIMP-2 mRNA level was not influenced. In male patients, only incubations with high doses (10(-5)M) of 17β-estradiol were followed by a tendency to suppressed MMP-1 and TIMP-1 levels while TIMP-2 mRNA level was decreased significantly. There was no effect on MMP-13 expression of cells from male patients. Taken together, application of 17β-estradiol in physiological doses will improve the imbalance between the amounts of MMPs and TIMPs in articular chondrocytes from female patients. Downregulation of TIMP-2 by 17β-estradiol in male patients would not be articular cartilage protective.

Estrogen attenuates the exercise pressor reflex in female cats.

In humans, the pressor and muscle sympathetic nerve responses to static exercise are less in women than in men. The difference has been attributed to the effect of estrogen on the exercise pressor reflex. Estrogen receptors are abundant in areas of the dorsal horn receiving input from group III and IV muscle afferents, which comprise the sensory limb of the exercise pressor reflex arc. These findings prompted us to investigate the effect of estrogen on the spinal pathway of the exercise pressor reflex arc. Previously, we found that the threshold concentration of 17beta-estradiol needed to attenuate the exercise pressor reflex in male decerebrate cats was 10 microg/ml (Schmitt PM and Kaufman MP. J Appl Physiol 94: 1431-1436, 2003). The threshold concentration for female cats, however, is not known. Consequently, we applied 17beta-estradiol to a well covering the L6-S1 spinal cord in decerebrate female cats. The exercise pressor reflex was evoked by electrical stimulation of the L7 or S1 ventral root, a maneuver that caused the hindlimb muscles to contract statically. We found that the pressor response to contraction averaged 38 +/- 7 mmHg before the application of 17beta-estradiol (0.01 microg/ml) to the spinal cord, whereas it averaged only 23 +/- 4 mmHg 30 min after application (P < 0.05). Recovery of the pressor response to contraction was not obtained for 2 h after application of 17beta-estradiol. Application of 17beta-estradiol in a dose of 0.001 microg/ml had no effect on the exercise pressor reflex (n = 5). We conclude that the concentration of 17beta-estradiol required to attenuate the exercise pressor reflex is 1,000 times more dilute in female cats than that needed to attenuate this reflex in male cats.

17β-Estradiol inhibits high-voltage-activated calcium channel currents in rat sensory neurons via a non-genomic mechanism

There is increasing evidence that estrogen influences electrical activity of neurons via stimulation of membrane receptors. Although the presence of intracellular estrogen receptors and their responsiveness in dorsal root ganglion (DRG) primary sensory neurons were reported, rapid electrical responses of estrogen in DRG neurons have not been reported yet. Therefore the current study was initiated to examine the rapid effects of estrogen on Ca 2+ channels and to determine its detailed mechanism in female rat DRG neurons using whole-cell patch-clamp recordings. Application of 17β-estradiol (1 μM) caused a rapid inhibition on high-voltage-activated (HVA)-, but not on low-voltage-activated (LVA)-Ca 2+ currents. This rapid estrogen-mediated inhibition was reproducible and dose-dependent. This effect was also sex- and stereo-specific; it was greater in cells isolated from intact female rats and was more effective than that of 17α-estradiol, the stereoisomer of the endogenous 17β-estradiol. In addition, ovariectomy reduced the inhibition significantly but this effect was restored by administration of estrogen in ovariectomized subjects. Occlusion experiments using selective blockers revealed 17β-estradiol mainly targeted on both L- and N-type Ca 2+ currents. Overnight treatment of cells with pertussis toxin profoundly reduced 17β-estradiol-mediated inhibition of the currents. On the other hand, estradiol conjugated to bovine serum albumin (EST-BSA) produced a similar extent of inhibition as 17β-estradiol did. These results suggest that 17β-estradiol can modulate L- and N-type HVA Ca 2+ channels in rat DRG neurons via activation of pertussis toxin-sensitive G-protein(s) and non-genomic pathways. It is likely that such effects are important in estrogen-mediated modulation of sensory functions at peripheral level.

Estrogen acutely inhibits ion transport by isolated stria vascularis

We investigated the nongenomic effects of female sex steroid hormones on the short circuit current ( I sc,probe) across gerbil stria vascularis using the voltage-sensitive vibrating probe. The strial marginal cell epithelial layer produces I sc,probe by secreting K + via I Ks channels in the apical membrane. Application of 17β-estradiol (E 2) caused a decrease of I sc,probe in a dose-dependent manner (10 nM–10 μM) within seconds. Tamoxifen, a competitive inhibitor of the intracellular estrogen receptor, did not change the inhibitory effect of E 2. Activation of I Ks channels by 4,4′-diisothiocyanatostilbene-2,2′-disulfonic acid in the presence and absence of E 2 was used to test the mechanism of action. The results were consistent with a direct inhibitory effect of E 2 on the I Ks channels. By contrast, progesterone caused a transient increase of I sc,probe. These results suggest that E 2 decreases secretion of K + by inhibition of I Ks channels via a nongenomic mechanism at concentrations near those occurring under some physiologic conditions while progesterone caused only transient effects on I sc,probe.

Effects of estrogen on action potential and membrane currents in guinea pig ventricular myocytes.

To explore a possible ionic basis for the prolonged Q-T interval in women compared with that in men, we investigated the electrophysiological effects of estrogen in isolated guinea pig ventricular myocytes. Action potentials and membrane currents were recorded using the whole cell configuration of the patch-clamp technique. Application of 17beta-estradiol (10-30 microM) significantly prolonged the action potential duration (APD) at 20% (APD(20)) and 90% repolarization (APD(90)) at stimulation rates of 0. 1-2.0 Hz. In the presence of 30 microM 17beta-estradiol, APD(20) and APD(90) at 0.1 Hz were prolonged by 46.2 +/- 17.1 and 63.4 +/- 11.7% of the control (n = 5), respectively. In the presence of 30 microM 17beta-estradiol the peak inward Ca(2+) current (I(CaL)) was decreased to 80.1 +/- 2.5% of the control (n = 4) without a shift in its voltage dependence. Application of 30 microM 17beta-estradiol decreased the rapidly activating component of the delayed outward K(+) current (I(Kr)) to 63.4 +/- 8% and the slowly activating component (I(Ks)) to 65.8 +/- 8.7% with respect to the control; the inward rectifier K(+) current was barely affected. The results suggest that 17beta-estradiol prolonged APD mainly by inhibiting the I(K) components I(Kr) and I(Ks).

Hormonal Breast Augmentation: Prognostic Relevance of Insulin-Like Growth Factor-I

Many women would like to alter their breasts but are deterred by the risks involved. Silicone breast implants have been linked to a variety of illnesses, the most controversial of which are connective-tissue diseases. These circumstances urged us to perform this pilot study using a non-invasive method that involved the application of 17β-estradiol as it is known that estradiol enhances expression of insulin-like growth factor-I (IGF-I) which can promote growth in breast tissue.Forty five women were included in the study. Their breast volume, IGF-I, prolactin (PRL) and estradiol levels were measured before treatment and between each application of 80 mg estradiol polyphosphate. The women's satisfaction with the results obtained was also subsequently evaluated.In 21 women (46.7%), breast size increased from 824.3 ± 13.7 mm to 898.5 ± 12.5 mm after 6 months. In these women a significant increase in IGF-I values was noted after 4 weeks of treatment. The increase in IGF-I values was not statistically significant in the remaining women. In addition, treatment was not successful in these women.IGF-I concentration seems to be of prognostic value as far as the response of breast tissue to estrogen stimulation is concerned. If IGF-I levels do not increase within 1 month, treatment should be discontinued. If IGF-I values do increase, this indicates that treatment is likely to be successful and can therefore be continued.