High-dose E2 Research Articles

Effects of dietary supplementation with 17β-estradiol and 17α-methyltestosterone on growth performance and gonadal development of the juvenile oriental river prawn (Macrobrachium nipponense)

17β-Estradiol (E2) and 17α-methyltestosterone (MT) are steroid hormones with dramatic regulatory effects on the growth performance and gonadal development of aquatic species. The aim of the present study was to investigate the regulatory effects of E2 and MT on the growth performance and gonadal development of juvenile prawns (Macrobrachium nipponense). Male and female juvenile prawns were separately maintained and fed different concentrations of E2 and MT, respectively. Treatment with both E2 and MT at 500 mg/kg dramatically promoted the growth of male and female juvenile prawns, respectively (p < 0.05). The growth rate of M. nipponense treated with E2 and MT at 1000 mg/kg at 30 days were 2.59 ± 0.31 and 2.21 ± 0.37, which were almost two- and five-fold greater than that of the control group, respectively. E2 showed better effects on the promotion of growth performance than MT. Histologically, testicular and ovarian development were delayed at E2 and MT concentrations of ≥ 500 mg/kg. Sperm had normally developed after 15 and 30 days of E2 treatment at ≤ 250 mg/kg, but were rarely observed in the testis at E2 concentrations greater than 500 mg/kg. The number of prawns at ovarian stages Ⅳ and V was increased with decreased MT concentrations. The qPCR results revealed that the expression levels of sperm gelatinase and insulin-like androgenic gland hormone were significantly decreased after E2 treatment from 100 mg/kg as compared to the control group (p < 0.05), while the expression levels at different E2 concentrations remained stable (p > 0.05). The expression levels of vitellogenin and vitellogenin receptor were dramatically decreased with increased MT concentrations, and the lowest expression levels were observed in the group treated with 1000 mg/kg (p < 0.05). Testosterone levels decreased with increased E2 concentrations (p < 0.05). In addition, lower MT concentrations (≤ 250 mg/kg) stimulated the secretion of E2 (p < 0.05), while higher concentrations (500 and 1000 mg/kg) had an opposite effect (p < 0.05). In summary, dietary supplementation with high doses of E2 and MT (500 and 1000 mg/kg) promoted the growth and inhibited gonadal development of juvenile M. nipponense. These findings provide important evidence of the effects of MT and E2 on the growth performance and gonadal development of juvenile M. nipponense, thereby establishing an artificial technique to regulate gonadal development.

Oestrogen treatment modulates the impact of cognitive experience and task complexity on memory in middle-aged surgically menopausal rats.

Menopause has been linked to changes in memory. Oestrogen-containing hormone therapy is prescribed to treat menopause-related symptoms and can ameliorate memory changes, although the parameters impacting oestrogen-related memory efficacy are unclear. Cognitive experience and practice have been shown to be neuroprotective and to improve learning and memory during ageing, with the type of task playing a role in subsequent cognitive outcomes. Whether task complexity matters, and whether these outcomes interact with menopause and oestrogen status, remains unknown. To investigate this, we used a rat model of surgical menopause to systematically assess whether maze task complexity, as well as order of task presentation, impacts spatial learning and memory during middle age when rats received vehicle, low-17β-oestradiol (E2 ) or high-E2 treatment. The direction, and even presence, of the effects of prior maze experience differed depending on the E2 dose. Surgical menopause without E2 treatment yielded the least benefit, as prior maze experience did not have a substantial effect on subsequent task performance for vehicle treated rats regardless of task demand level during the first exposure to maze experience or final testing. High-dose E2 yielded a variable benefit, and low-dose E2 produced the greatest benefit. Specifically, low-dose E2 broadly enhanced learning and memory in surgically menopausal rats that had prior experience on another task, regardless of the complexity level of this prior experience. These results demonstrate that E2 dose influences the impact of prior cognitive experience on learning and memory during ageing, and highlights the importance of prior cognitive experience in subsequent learning and memory outcomes.

An estradiol-17β/miRNA-26a/cyp19a1a regulatory feedback loop in the protogynous hermaphroditic fish, Epinephelus coioides

Cyp19a1a is a key gene responsible for the production of estradiol-17β (E2), the main functional estrogen and a major downstream regulator of reproduction in teleost fish. It is widely known that CYP19 gene expression, aromatase activity, and E2 production can influence gonadal differentiation and sex reversal in teleost fish, but the feedback mechanisms whereby E2 regulates cyp19a1a remain poorly understood, especially regarding the potential roles of endogenous small RNA molecules (miRNAs). Here, we identified miR-26a-5p as a regulatory factor of its predicted target gene (cyp19a1a). In vitro and in vivo studies showed that miR-26a-5p can decrease cyp19a1a expression. Furthermore, high doses of E2 act as a repressor of miR-26a-5p. This study proposes a regulatory feedback loop whereby E2 regulates cyp19a1a through miR-26a-5p, and suggests that this positive feedback is an important aspect of the control of E2 production.

Bone turnover markers in women participating in a dose-finding trial of a contraceptive vaginal ring releasing Nestorone and estradiol

ObjectiveTo evaluate changes in the bone turnover markers CTx and P1NP during 6 months' use of novel continuous contraceptive vaginal rings delivering Nestorone (NES) 200 mcg/day and three doses of estradiol (E2) (10, 20, and 40 mcg/day). Study designThis randomized trial enrolled 189 women who used two consecutive vaginal rings over 180 days. Frequent blood sampling permitted analysis of NES, E2, CTx and P1NP concentrations. The bone-turnover marker analyses included only women with complete sampling and excluded women with characteristics that might interfere with accurate measurement of bone markers such as afternoon sampling, poor ring compliance or recent pregnancy. We evaluated the change from baseline to 6 months in CTx and P1NP, stratified by ring dose and by average circulating E2 concentrations. ResultsOne hundred fifty-one women completed the study, and 82 women had complete data available for the bone marker analyses; the three dosage groups were balanced with regard to baseline characteristics. E2 concentrations remained low throughout treatment, regardless of which dose ring the participant used. Individual CTx changes from baseline averaged 27±56% (p<.01). Similarly, individual P1NP changes averaged 11±33% (p=.04). These increases were within the premenopausal reference ranges, and unrelated to treatment dose or to circulating E2 concentrations. ConclusionsThe low E2 dose of these rings was associated with low E2 concentrations and modest increases in serum bone turnover makers. Because we have only 6-month bone turnover markers and no direct evidence of bone loss or bone density change, these results must be interpreted with caution. ImplicationsNestorone, a 19-norprogesterone derivative, leads to complete ovarian suppression, which should yield excellent contraceptive effectiveness. To prevent potential adverse effects on bone, the NES contraceptive ring should be combined with higher doses of E2 than were assessed in this study.

Methylation of HIF3A promoter CpG islands contributes to insulin resistance in gestational diabetes mellitus.

BackgroundGestational diabetes mellitus (GDM) is defined as any degree of glucose intolerance during pregnancy, and will lead to high risk of diabetes even after pregnancy. Hypoxia‐inducible factor (HIF) family proteins are transcriptional factors that are highly correlated with methylation, which might be involved in the regulation of GDM.MethodsBaseline clinical characteristics of the GDM patients and healthy women were analyzed. Omental tissue from GDM patients and control groups were collected and detected for the expression levels of HIF1A, HIF2A, and HIF3A. The CpG islands of HIF3A promoter were predicted by “methprimer” software, and the methylation level of CpG islands was detected by bisulfite sequencing PCR.Results HIF3A was downregulated in the omental tissue from GDM patients, whereas HIF1A and HIF2A were not affected. Furthermore, HIF3A expression was positively correlated with levels of estrogen receptor α (ESR1) and solute carrier family 2 member 4 (SLC2A4). Moreover, CpG islands of HIF3A promoter were highly methylated in GDM patients. In addition, methylation level of CpG islands could be upregulated by Estradiol (E2) treatment, since high dose of E2 reduced HIF3A mRNA expression in 3T3‐L1 adipocytes.ConclusionOur findings demonstrate that the expression level of HIF3A, but not HIF1A or HIF2A, is downregulated in GDM patients. The methylation status of HIF3A promoter region is highly correlated with GDM, which could be a novel therapeutic target for GDM treatment.

Effect of feed restriction on hepatic estradiol metabolism and liver function in cows

In this study, the effects of restriction feeding on the liver function, hepatic uridine diphosphate glucuronosyltransferase (UGT) activity, hepatic insulin-like growth factor (IGF)-1 mRNA expression and response to high-dose estradiol-17β (E2) administration were investigated in non-lactating cows. Cows were assigned to either restricted feeding (30% of total digestible nutrient requirement) or ad libitum feeding of a dent corn-based concentrate and roughage for a 2-week feeding trial (Day 1=day of beginning the feeding trial). On day 14, a high-dose E2 administration study was carried out to examine plasma E2 levels as an indicator of hepatic E2 metabolism. Plasma E2 concentration in the restricted feeding group was consistently higher after high-dose E2 administration than in the control group. In addition, indocyanine green half-life value was prolonged by restricted feeding for 13 days, and increased liver triglyceride concentration and decreased liver UGT activity were caused by this restriction over 14 days. Restricted feeding did not affect plasma IGF-1 concentration or hepatic IGF-1 mRNA expression. These results suggest that two weeks of restriction feeding led to accumulation of triglyceride, decreased liver blood flow, and slightly impaired liver function, which in turn slowed down the hepatic metabolism of E2 without significantly impacting hepatic IGF-1 production.

Interruption of immune responses in primary macrophages exposed to nonylphenol provides insights into the role of ER and NF-KB in immunotoxicity of Persian sturgeon

The severe decline in population of sturgeons due to pollution highlighted poor understanding about the immunotoxicological responses of sturgeons. This study was designed in three experiments to find out how nonylphenol (NP) interrupts some pro-inflammatory immune parameters in macrophages from Persian sturgeon (Acipencer persicous) as the oldest vertebrate model conserving intact innate immune system. After determination of IC50 values of NP (200 μM), some pro-inflammatory immune parameters and induced apoptosis in macrophages at low dose (10 nM) and high dose (100 nM) of NP and of 17β estradiol (E2) (positive control) were determined after 6, 24 and 48 h of the exposure (as the first experiment). The two doses of NP induced pro-inflammatory reaction and apoptosis with strong correlations, whereas this result was observed more obviously in high dose of E2. In the second experiments, the macrophages were exposed to the two doses of NP along with estrogen receptor alpha (ERα) antagonist, which consequently decreased the induction of pro-inflammatory reactions. Similarly, in the third experiment, NF-KB and ERα antagonists were used and pro-inflammatory reactions decreased compared to the control group (P < 0.05). Decreasing correlation between immune parameters following the second and third experiments verified interaction between ERα and NF-KB pathways. Thus, NP could be immune disrupter and apoptosis inducer in sturgeon macrophages in vitro, even in low dose. For the first time, this study revealed that NP can induce pro-inflammatory reactions in macrophages derived from sturgeons.

Impact of Perfluorooctane Sulfonate on Reproductive Ability of Female Mice through Suppression of Estrogen Receptor α-Activated Kisspeptin Neurons.

Perfluorooctane sulfonate (PFOS) is used extensively in industrial and household applications. High exposure to PFOS has been associated with increased odds of irregular and long menstrual cycles in women. However, the underlying mechanisms remain to be elucidated. Herein, we show that adult female mice appeared prolongation of diestrus and reduction of corpora luteum within a week of oral administration of PFOS (10 mg/kg), which are associated with decreases in the levels of serum progesterone, LH and hypothalamic GnRH. The number of AVPV-kisspeptin neurons and the AVPV-kisspeptin expression were increased in proestrus mice or OVX-mice treated with high-dose estradiol benzoate (0.05 mg/kg), which were suppressed by the administration of PFOS. The administration of PFOS or GPR54 antagonist P234 prevented the generation of LH-surge in OVX-mice treated with high-dose E2. In hypothalamic slices incubated in 100 nM E2 for 4 h, the AVPV-kisspeptin expression was significantly enhanced, which was inhibited by PFOS in a dose-dependent manner or estrogen receptor α (ERα) antagonist MPP, but not ERβ antagonist PHTPP. The incubation of ERα agonist PPT rather than ERβ agonist DPN could increase the level of AVPV-kisspeptin expression, which was sensitive to the treatment with PFOS. The administration of GPR54 agonist kisspeptin-10 in PFOS-mice could correct the prolongation of diestrus and reduction of corpora luteum, and recover the LH-surge and the levels of LH and GnRH. The results indicate that exposure to PFOS suppressed ERα-induced activation of AVPV-kisspeptin neurons leads to diestrus prolongation and ovulation reduction.

Gestational oral low-dose estradiol-17\u03b2 induces altered DNA methylation of CDKN2D and PSAT1 in embryos and adult offspring

Endocrine disrupting chemicals (EDC) interfere with the natural hormone balance and may induce epigenetic changes through exposure during sensitive periods of development. In this study, the effects of short-term estradiol-17β (E2) exposure on various tissues of pregnant sows (F0) and on day 10 blastocysts (F1) were assessed. Intergenerational effects were investigated in the liver of 1-year old female offspring (F1). During gestation, sows were orally exposed to two low doses and a high dose of E2 (0.05, 10, and 1000 µg/kg body weight/day). In F0, perturbed tissue specific mRNA expression of cell cycle regulation and tumour suppressor genes was found at low and high dose exposure, being most pronounced in the endometrium and corpus luteum. The liver showed the most significant DNA hypomethylation in three target genes; CDKN2D, PSAT1, and RASSF1. For CDKN2D and PSAT1, differential methylation in blastocysts was similar as observed in the F0 liver. Whereas blastocysts showed hypomethylation, the liver of 1-year old offspring showed subtle, but significant hypermethylation. We show that the level of effect of estrogenic EDC, with the periconceptual period as a sensitive time window, is at much lower concentration than currently presumed and propose epigenetics as a sensitive novel risk assessment parameter.

Brain Aromatase Modulates Serotonergic Neuron by Regulating Serotonin Levels in Zebrafish Embryos and Larvae.

Teleost fish are known to express two isoforms of P450 aromatase, a key enzyme for estrogen synthesis. One of the isoforms, brain aromatase (AroB), cyp19a1b, is highly expressed during early development of zebrafish, thereby suggesting its role in brain development. On the other hand, early development of serotonergic neuron, one of the major monoamine neurons, is considered to play an important role in neurogenesis. Therefore, in this study, we investigated the role of AroB in development of serotonergic neuron by testing the effects of (1) estradiol (E2) exposure and (2) morpholino (MO)-mediated AroB knockdown. When embryos were exposed to E2, the effects were biphasic. The low dose of E2 (0.005 µM) significantly increased serotonin (5-HT) positive area at 48 hour post-fertilization (hpf) detected by immunohistochemistry and relative mRNA levels of tryptophan hydroxylase isoforms (tph1a, tph1b, and tph2) at 96 hpf measured by semi-quantitative PCR. To test the effects on serotonin transmission, heart rate and thigmotaxis, an indicator of anxiety, were analyzed. The low dose also significantly increased heart rate at 48 hpf and decreased thigmotaxis. The high dose of E2 (1 µM) exhibited opposite effects in all parameters. The effects of both low and high doses were reversed by addition of estrogen receptor (ER) blocker, ICI 182,780, thereby suggesting that the effects were mediated through ER. When AroB MO was injected to fertilized eggs, 5-HT-positive area was significantly decreased, while the significant decrease in relative tph mRNA levels was found only with tph2 but not with two other isoforms. AroB MO also decreased heart rate and increased thigmotaxis. All the effects were rescued by co-injection with AroB mRNA and by exposure to E2. Taken together, this study demonstrates the role of brain aromatase in development of serotonergic neuron in zebrafish embryos and larvae, implying that brain-formed estrogen is an important factor to sustain early development of serotonergic neuron.

Physiological low-dose oestrogen promotes the development of experimental autoimmune thyroiditis through the up-regulation of Th1/Th17 responses

Previous studies have reported a preponderance of autoimmune thyroiditis (AIT) in females, but the detailed mechanisms have not been elucidated. In this study, we explored the effects of oestrogen on experimental AIT (EAT) and its potential mechanisms in an ovariectomised mouse model through the supplementation of high (equivalent to the level during pregnancy) or low (equivalent to the level at the oestrus stage) doses of oestradiol (E2). We found that EAT incidence, the intrathyroidal inflammatory score, serum anti-thyroglobulin IgG2b levels, splenic mRNA expression of Th1- and Th17-specific transcription factors and typical cytokines and the proportion of IL-12-producing dendritic cells were significantly increased in EAT mice treated with low-dose E2 compared with those in the control group. However, they were not changed when administered with high-dose E2. These findings indicate that low physiological levels of E2 can stimulate the occurrence and development of EAT through the up-regulation of Th1/Th17 responses.

Conventional DCs from Male and Female Lupus-Prone B6.NZM Sle1/Sle2/Sle3 Mice Express an IFN Signature and Have a Higher Immunometabolism That Are Enhanced by Estrogen.

Type I interferons (IFN) are pathogenic in systemic lupus erythematosus (SLE) and were proposed to control the immunometabolism of dendritic cells (DCs). We previously reported that DCs from female lupus-prone mice constitutively overexpress IFN-responsive genes resembling the IFN signature found in SLE patients. As SLE has higher incidence in women than men, more so in women of reproductive age, estrogens are suggested to affect lupus pathogenesis. We investigated the effects of sex and estrogens on the IFN signature in conventional GM-CSF-bone marrow-derived DCs (cDCs), from male and female Triple Congenic B6.NZM.Sle1/Sle2/Sle3 (TCSle) lupus-prone mice or from wild-type C57BL/6 mice, generated with titrations of 17-beta-estradiol (E2). We found that cDCs from prediseased TCSle male mice express the IFN signature as female TCSle cDCs do. Estrogens are necessary but not sufficient to express this IFN signature, but high doses of E2 can compensate for other steroidal components. E2 stimulation, regardless of sex, modulates type I IFN-dependent and type I IFN-independent activation of cDCs in response to TLR stimulation. Finally, we found that TCSle cDCs from both sexes have elevated markers of immunometabolism and estrogens enhance the metabolic pathways in cDCs, suggesting a mechanistic link between estrogens, immunometabolism, and the IFN signature in lupus.

Distinct dynorphin expression patterns with low- and high-dose estrogen treatment in the arcuate nucleus of female rats.

Kisspeptin (KISS1; encoded by Kiss1) neurons in the arcuate nucleus (ARC) coexpress tachykinin 3 (TAC3; also known as neurokinin B) and dynorphin A (PDYN). Accordingly, they are termed KNDy neurons and considered to be crucial in generating pulsatile release of gonadotropin-releasing hormone. Accumulating evidence suggests that Kiss1 and Tac3 are negatively regulated by estrogen. However, it has not been fully determined whether and how estrogen modulates Pdyn and PDYN. Here, we examined the expression of Pdyn mRNA and PDYN by in situ hybridization and immunohistochemistry, respectively, in the ARC of female rats after ovariectomy (OVX) and OVX plus low- or high-dose beta-estradiol (E2) replacement. We also investigated the effect of E2 on expression of Kiss1, KISS1, Tac3, and TAC3. Furthermore, colocalization of PDYN and estrogen receptor alpha (ESR1) was determined. Subsequently, we found that low-dose E2 treatment had no effect on Pdyn mRNA-expressing cells, but increased PDYN-immunoreactive (ir) cell numbers. In contrast, high-dose E2 treatment resulted in prominent reductions in both Pdyn mRNA-expressing and PDYN-ir cell numbers. Changes induced by low or high doses of E2 were similarly observed in the expression of Kiss1, KISS1, Tac3, and TAC3. The majority of PDYN-ir neurons coexpressed ESR1 in all groups. Our results indicate that E2 regulates the expression of PDYN, as well as KISS1 and TAC3, with regulation by E2 differing according to its levels.

Regulation of bone growth via ligand-specific activation of estrogen receptor alpha.

Estrogens are well known for their capacity to promote bone maturation and at high doses to induce growth plate closure and thereby stop further growth. High-dose estrogen treatment has therefore been used to limit growth in extremely tall girls. However, recent data suggest that this treatment may have severe side effects, including increased risk of cancer and reduced fertility. We hypothesized that estrogenic effects in bone are mediated via ERα signaling. Twelve-week-old ovariectomized female C57BL/6 mice were subcutaneously injected for 4 weeks with E2 or selective ERα (PPT) or ERβ (DPN) agonists. After killing, tibia and femur lengths were measured, and growth plate morphology was analyzed. E2- and PPT-treated mice had shorter tibiae and femur bones when compared to vehicle-treated controls, whereas animals treated with DPN had similar bone lengths compared to controls. Growth plate height and hypertrophic zone height were reduced in animals treated with E2 or PPT but not in those treated with DPN, supporting that the effect was mediated via ERα. Moreover, PCNA staining revealed suppressed proliferation of chondrocytes in the tibia growth plate in PPT- or E2-treated mice compared to controls. Our data show that estrogenic effects on bone growth and growth plate maturation are mainly mediated via ERα. Our findings may have direct implications for the development of new and more selective treatment modalities of extreme tall stature using selective estrogen receptor modulators that may have low side effects than high-dose E2 treatment.

Estrogens Exacerbate Nociceptive Pain via Up-Regulation of TRPV1 and ANO1 in Trigeminal Primary Neurons of Female Rats.

Several trigeminal pain disorders show sex differences, and high levels of estrogens may underlie these differences. The interaction between transient receptor potential vanilloid 1 (TRPV1) and anoctamin 1 (ANO1) plays an important role in peripheral nociception. However, whether TRPV1 and ANO1 are involved in estrogen-modulated trigeminal pain sensitivity is unclear. In this study, we examined estradiol (E2) modulation of nociception through behavioral and immunohistological experiments after application of capsaicin (Cap), a selective TRPV1 agonist, onto the ocular surface in ovariectomized rats treated with high-dose E2 (HE) or low-dose E2 (LE) for 2 days. In addition, we used real-time PCR to study the effects of E2 on the expression levels of TRPV1 and ANO1 mRNA in trigeminal ganglia. In the behavioral experiment, the HE group showed significant potentiation of Cap-evoked nocifensive behavior compared with the LE group. Immunohistochemistry showed that Cap evoked a significantly greater number of cells that were immunoreactive for c-Fos, a marker of nociceptive activation, in the trigeminal subnucleus caudalis/upper cervical cord in the HE group than in the LE group. The number of c-Fos-immunoreactive cells in the ventral trigeminal interpolaris/caudalis were similar in the 2 groups. Real-time PCR showed that the levels of TRPV1 and ANO1 mRNA in the HE group were significantly higher than levels in the LE group. Thus, high levels of estrogens may be a risk factor for Cap-evoked nociceptive pain, and estrogen-dependent increases in TRPV1 and ANO1 are likely involved in modulating the nociceptive response in the trigeminal area.

Ribosomal protein L7 as a suitable reference gene for quantifying gene expression in gastropod Bellamya aeruginosa.

Expression levels of eight candidate reference genes were quantified in tissues of gastropod Bellamya aeruginosa exposed for 10 d to various stressors, including fasting, 17β-estradiol, 17α-methyltestosterone, and Cd(2+). The results showed that 18s rRNA was the most highly expressed of the candidate reference genes, while H2A was the least expressed. There were no significant changes (p>0.05) in the expression of the eight genes in tissues among the different treatments. Using RefFinder to evaluate the expression stabilities of the eight candidate reference genes, ribosomal protein was shown to be the most stable reference gene, and no effects were observed among the different stressor treatments. These results indicate that RPL 7 is the most suitable reference gene for quantifying gene expression in B. aeruginosa under environmental stress, which was verified in B. aeruginosa exposed to high doses of E2 for 24 and 72h.

The deletion of the estrogen receptor α gene reduces susceptibility to estrogen-induced cholesterol cholelithiasis in female mice

Compelling evidence has demonstrated that estrogen is a critical risk factor for gallstone formation and enhances cholesterol cholelithogenesis through the hepatic estrogen receptor α (ERα), but not ERβ. To study the lithogenic mechanisms of estrogen through ERα, we investigated whether the deletion of Erα protects against gallstone formation in ovariectomized (OVX) female mice fed a lithogenic diet and treated with 17β-estradiol (E2) at 0 or 6μg/day for 56days. Our results showed that the prevalence of gallstones was reduced from 100% in OVX ERα (+/+) mice to 30% in OVX ERα (−/−) mice in response to high doses of E2 and the lithogenic diet for 56days. Hepatic cholesterol secretion was significantly diminished in OVX ERα (−/−) mice compared to OVX ERα (+/+) mice even fed the lithogenic diet and treated with E2 for 56days. These alterations decreased bile lithogenicity by reducing cholesterol saturation index of gallbladder bile. Immunohistochemical studies revealed that ERα was expressed mainly in the gallbladder smooth muscle cells. High levels of E2 impaired gallbladder emptying function mostly through the ERα and cholecystokinin-1 receptor pathway, leading to gallbladder stasis in OVX ERα (+/+) mice. By contrast, gallbladder emptying function was greatly improved in OVX ERα (−/−) mice. This markedly retarded cholesterol crystallization and the growth and agglomeration of solid cholesterol crystals into microlithiasis and stones. In conclusion, the deletion of Erα reduces susceptibility to the formation of E2-induced gallstones by diminishing hepatic cholesterol secretion, desaturating gallbladder bile, and improving gallbladder contraction function in female mice.

Nanoparticle Estrogen in Rat Spinal Cord Injury Elicits Rapid Anti-Inflammatory Effects in Plasma, Cerebrospinal Fluid, and Tissue.

Persons with spinal cord injury (SCI) are in need of effective therapeutics. Estrogen (E2), as a steroid hormone, is a highly pleiotropic agent; with anti-inflammatory, anti-apoptotic, and neurotrophic properties, it is ideal for use in treatment of patients with SCI. Safety concerns around the use of high doses of E2 have limited clinical application, however. To address these concerns, low doses of E2 (25 μg and 2.5 μg) were focally delivered to the injured spinal cord using nanoparticles. A per-acute model (6 h after injury) was used to assess nanoparticle release of E2 into damaged spinal cord tissue; in addition, E2 was evaluated as a rapid anti-inflammatory. To assess inflammation, 27-plex cytokine/chemokine arrays were conducted in plasma, cerebrospinal fluid (CSF), and spinal cord tissue. A particular focus was placed on IL-6, GRO-KC, and MCP-1 as these have been identified from CSF in human studies as potential biomarkers in SCI. S100β, an additional proposed biomarker, was also assessed in spinal cord tissue only. Tissue concentrations of E2 were double those found in the plasma, indicating focal release. E2 showed rapid anti-inflammatory effects, significantly reducing interleukin (IL)-6, GRO-KC, MCP-1, and S100β in one or all compartments. Numerous additional targets of rapid E2 modulation were identified including: leptin, MIP-1α, IL-4, IL-2, IL-10, IFNγ, tumor necrosis factor-α, etc. These data further elucidate the rapid anti-inflammatory effects E2 exerts in an acute rat SCI model, have identified additional targets of estrogen efficacy, and suggest nanoparticle delivered estrogen may provide a safe and efficacious treatment option in persons with acute SCI.

Estrogen induced concentration dependent differential gene expression in human breast cancer (MCF7) cells: Role of transcription factors

BackgroundBreast cancer cells respond to estrogen in a concentration dependent fashion, resulting in proliferation or apoptosis. The mechanism of this concentration dependent differential outcome is not well understood yet. MethodologyMeta-analysis of the expression data of MCF7 cells treated with low (1nM) or high (100nM) dose of estradiol (E2) was performed. We identified genes differentially expressed at the low or the high dose, and examined the nature of regulatory elements in the vicinity of these genes. Specifically, we looked for the difference in the presence, abundance and spatial distribution of binding sites for estrogen receptor (ER) and selected transcription factors (TFs) in the genomic region up to 25kb upstream and downstream from the transcription start site (TSS) of these genes. ResultsIt was observed that at high dose E2 induced the expression of stress responsive genes, while at low dose, genes involved in cell cycle were induced. We found that the occurrence of transcription factor binding regions (TFBRs) for certain factors such as Sp1 and SREBP1 were higher on regulatory regions of genes expressed at low dose. At high concentration of E2, genes with a higher frequency of Oct-1 binding regions were predominantly involved. In addition, there were differences in the spatial distribution pattern of the TFBRs in the genomic regions among the two sets of genes. DiscussionE2 induced predominantly proliferative/metabolic response at low concentrations; but at high concentration, stress–rescue responses were induced. At high E2 concentration, classical genomic pathway involving ER binding to the regulatory regions was reduced, and alternate or indirect activation of genes through Oct-1 became more prominent.

Social status modifies estradiol activation of sociosexual behavior in female rhesus monkeys

Estrogen (E2) has activational effects on sexual motivation and mitigating effects on anxiety-like behaviors that can be attenuated with chronic exposure to psychosocial stress. Some studies suggest that this attenuation can be overcome by higher doses of E2, while others show that chronic psychosocial stress may alter the mechanisms of E2 function, thus reducing any positive benefit from higher doses of E2. To determine the interaction between psychosocial stress and E2 dose on behavior, we examined the scope of attenuation across a suite of socioemotional behaviors, including reproduction, affiliation, aggression, submission, and anxiety-like behaviors on 36 ovariectomized female rhesus monkeys. Females were exposed to graded psychosocial stress, established by an intrinsic female dominance hierarchy, where subordinate animals receive high amounts of harassment. Our data show that E2 dose-dependently increased sexual motivation and male-affiliation in dominant (e.g. low-stress) females, while subordinate females showed no positive effects of E2, even at higher doses. In addition, contact aggression was attenuated in dominant females, while non-contact aggression was attenuated in both dominant and middle-ranking females. These results suggest that the stress-induced attenuation of E2's activational effects on sexual behavior and affiliation with males may not be overcome with higher doses of E2. Furthermore, the observed behavioral consequences of psychosocial stress and E2 dose may be dependent on the behaviors of all the females in the social-group, and better resolution on these effects depends on isolating treatment to individuals within the group to minimize alterations in social-group interactions.