Comparative effects of estradiol, methyl-piperidino-pyrazole, raloxifene, and ICI 182 780 on gene expression in the murine uterus

Identification of Potentially Novel Molecular Targets of Endometrial Cancer Using a Non-Biased Proteomic Approach

The present study was aimed at identifying novel proteins in endometrial cancer (EC), employing proteomic analysis of tissues obtained after surgery. A differential MS-based proteomic analysis was conducted from whole tissues dissected from biopsies from post-menopausal women, histologically confirmed as endometrial cancer (two endometrioid and two serous; n = 4) or normal atrophic endometrium (n = 4), providing 888 differentially expressed proteins with 246 of these previously documented elsewhere as expressed in EC and 372 proteins not previously demonstrated to be expressed in EC but associated with other types of cancer. Additionally, 33 proteins not recorded previously in PubMed as being expressed in any forms of cancer were also identified, with only 26 of these proteins having a publication associated with their expression patterns or putative functions. The putative functions of the 26 proteins (GRN, APP, HEXA, CST3, CAD, QARS, SIAE, WARS, MYH8, CLTB, GOLIM4, SCARB2, BOD1L1, C14orf142, C9orf142, CCDC13, CNPY4, FAM169A, HN1L, PIGT, PLCL1, PMFBP1, SARS2, SCPEP1, SLC25A24 and ZC3H4) in other tissues point towards and provide a basis for further investigation of these previously unrecognised novel EC proteins. The developmental biology, disease, extracellular matrix, homeostatic, immune, metabolic (both RNA and protein), programmed cell death, signal transduction, molecular transport, transcriptional networks and as yet uncharacterised pathways indicate that these proteins are potentially involved in endometrial carcinogenesis and thus may be important in EC diagnosis, prognostication and treatment and thus are worthy of further investigation.

Inhibitory effects of estrogenic endocrine disrupting chemicals on fin regeneration in zebrafish are dependent on estrogen receptors

For fish and other aquatic organisms, disrupting their capacity for repair and regeneration will reduce their quality of life and survivorship in the wild. Studies have shown that 17α-ethinylestradiol (EE2), a synthetic estrogenic endocrine disrupting chemical (EEDC), can inhibit caudal fin regeneration in larval zebrafish following fin amputation. However, whether the inhibitory effects of EE2 are dependent on estrogen receptor (ER) remains unknown. Therefore, in this study, amputated zebrafish larvae were exposed to the ER agonist EE2 alone and in combination with the ER antagonist ICI 182,780 (ICI), and the change in regenerative capacity was determined. The inhibition of fin regeneration caused by EE2 alone (100 ng/L) was ameliorated after combination with ICI (30-300 μg/L), and these changes in regeneration-related signaling and the immune system corresponded with morphological observations, implying that the effects of EE2 on regeneration were possibly initiated by the activation of ER. Furthermore, the role of ER was confirmed with a natural ligand of ER, namely, 17β-estradiol (E2), and as expected, the effects of E2 (10, 100 and 1000 ng/L) paralleled those of EE2. In conclusion, EEDCs can disrupt the regenerative capacity in zebrafish, possibly due to the binding and activation of ERs and the consequent alteration of signaling pathways that regulate fin regeneration and immune competence. Given that EEDCs appear to be ubiquitous in the aquatic environment, the risk of these chemicals might be readdressed regarding their potential effects on tissue repair and regeneration.

Icariin Alleviates Wear Particle-Induced Periprosthetic Osteolysis via Down-Regulation of the Estrogen Receptor α-mediated NF-κB Signaling Pathway in Macrophages

Periprosthetic osteolysis is one of the major long-term complications following total joint replacement. Its cause is widely accepted to be wear particle-induced activation of inflammatory macrophages. No effective strategy for the prevention and treatment of periprosthetic osteolysis is yet available. Recently, considerable evidence has shown that icariin effectively protects against estrogen deficiency-related bone loss and bone deterioration. However, the molecular mechanism underlying the inhibitory effect of icariin on wear particle-induced periprosthetic osteolysis is not yet clear. In this study, nanoscale CoCrMo wear particles were obtained by high-vacuum three-electrode direct current from the femoral head implant of a patient diagnosed with aseptic loosening. The effects of icariin on wear particle-induced expression of proinflammatory factors, NF-κB signaling modulation, osteolysis, and estrogen receptor α (ERα) activation were evaluated in vitro and in vivo using bone marrow-derived macrophages and C57/BL6J mice, respectively. A possible link between ERα and the protective effect of icariin was further studied using an ERα antagonist and the ERα-siRNA interference. Chemical composition analysis showed that Cr and Co were the major metallic elements of the nanoscale particles, with a mean size of 150.2 ± 37.4 nm for the CoCrMo particles. Following icariin treatment, significant decreases were observed in CoCrMo wear particle-induced TNF-α and IL-6 mRNA expression in BMDMs, and osteolysis in mice calvaria. Marked decreases in the protein expression level of p-IKKβ, p-p65 and p-IκBα were also observed, together with significant decreases in the nuclear import of P65 and macrophage M1 polarization. RNA sequencing revealed that ERα was closely associated with TNF-α and IL-6 in wear particle-stimulated macrophages. Furthermore, marked increases in phospho-ERα Ser118 and phospho-ERα Ser167 protein expression and the nuclear import of ERα were also found in the icariin group. The protective effects of icariin on CoCrMo particle-induced mouse calvarial osteolysis and on the inflammation response in BMDMs were reversed by ERα antagonist and by ERα-siRNA interference. In conclusion, icariin attenuates wear particle-induced inflammation and osteolysis via down-regulation of the ERα-mediated NF-κB signaling pathway in macrophages. The potential application of icariin as a non-hormonal therapy for wear particle-induced periprosthetic osteolysis is worthy of further investigation.

Estradiol treatment attenuates high fat diet-induced microgliosis in ovariectomized rats

Consumption of a high fat diet (HFD) increases circulating free fatty acids, which can enter the brain and promote a state of microgliosis, as defined by a change in microglia number and/or morphology. Most studies investigating diet-induced microgliosis have been conducted in male rodents despite well-documented sex differences in the neural control of food intake and neuroimmune signaling. This highlights the need to investigate how sex hormones may modulate the behavioral and cellular response to HFD consumption. Estradiol is of particular interest since it exerts a potent anorexigenic effect and has both anti-inflammatory and neuroprotective effects in the brain. As such, the aim of the current study was to investigate whether estradiol attenuates the development of HFD-induced microgliosis in female rats. Estradiol- and vehicle-treated ovariectomized rats were fed either a low-fat chow diet or a 60% HFD for 4 days, after which they were perfused and brain sections were processed via immunohistochemistry for microglia-specific Iba1 protein. Four days of HFD consumption promoted microgliosis, as measured via an increase in the number of microglia in the arcuate nucleus (ARC) of the hypothalamus and nucleus of the solitary tract (NTS), and a decrease in microglial branching in the ARC, NTS, lateral hypothalamus (LH), and ventromedial hypothalamus. Estradiol replacement attenuated the HFD-induced changes in microglia accumulation and morphology in the ARC, LH, and NTS. We conclude that estradiol has protective effects against HFD-induced microgliosis in a region-specific manner in hypothalamic and hindbrain areas implicated in the neural control of food intake.

Myopia disease mouse models: a missense point mutation (S673G) and a protein-truncating mutation of the Zfp644 mimic human disease phenotype

Zinc finger 644 (Zfp644 in mouse, ZNF644 in human) gene is a transcription factor whose mutation S672G is considered a potential genetic factor of inherited high myopia. ZNF644 interacts with G9a/GLP complex, which functions as a H3K9 methyltransferase to silence transcription. In this study, we generated mouse models to unravel the mechanisms leading to symptoms associated with high myopia. Employing TALEN technology, two mice mutants were generated, either with the disease-carrying mutation (Zfp644^S673G) or with a truncated form of Zfp644 (Zfp644^Δ8). Eye morphology and visual functions were analysed in both mutants, revealing a significant difference in a vitreous chamber depth and lens diameter, however the physiological function of retina was preserved as found under the high-myopia conditions. Our findings prove that ZNF644/Zfp644 is involved in the development of high-myopia, indicating that mutations such as, Zfp644^S673G and Zfp644^Δ8 are causative for changes connected with the disease. The developed models represent a valuable tool to investigate the molecular basis of myopia pathogenesis and its potential treatment.

Gonadotropin-releasing hormone agonist induces downregulation of tensin 1 in women with endometriosis

INTRODUCTION

Many cell migration-related molecules are associated with endometriosis. Tensin 1 (TNS1), which has been implicated in cell migration, may play a role in endometriosis. The study goal was to evaluate the TNS1 expression in endometrial tissue and serum from women with endometriosis treated with gonadotropin-releasing hormone agonist (GnRHa).

MATERIAL AND METHODS

Tissue and serum samples were collected from women with endometriosis who were treated (n = 29) with GnRHa or untreated (n = 30). TNS1 mRNA was examined using quantitative PCR. TNS1 protein levels in tissue and serum samples were investigated using Western blot, immunohistochemistry and ELISA. Eleven women with endometriosis participated in a follow-up investigation of serum TNS1 before and after GnRHa treatment.

RESULTS

TNS1 mRNA (P = 0.006) and protein (P = 0.001) were significantly downregulated in endometriotic tissue from women with endometriosis who received GnRHa. Immunolocalization of TNS1 showed strong expression in the epithelial and stromal cells of endometriotic tissue from women untreated with GnRHa, whereas endometriotic tissue from GnRHa-treated women showed low TNS1 expression. Follow-up monitoring of serum TNS1 concentration in 11 women showed an average decrease in concentration of 53%, from 294.9 ± 66.69 to 140.3 ± 55.21 pg/mL, following GnRHa treatment (P = 0.003).

CONCLUSIONS

GnRHa induces downregulation of TNS1 in tissue and serum in women with endometriosis. These results emphasize the importance TNS1 as a potential therapeutic molecular target for the treatment of endometriosis with GnRHa.

Selective activation of estrogen receptors, ERα and GPER-1, rapidly decreases food intake in female rats

Many of estradiol's behavioral effects are mediated, at least partially, via extra-nuclear estradiol signaling. Here, we investigated whether two estrogen receptor (ER) agonists, targeting ERα and G protein-coupled ER-1 (GPER-1), can promote rapid anorexigenic effects. Food intake was measured in ovariectomized (OVX) rats at 1, 2, 4, and 22 h following subcutaneous (s.c.) injection of an ERα agonist (PPT; 0-200 μg/kg), a GPER-1 agonist (G-1; 0-1600 μg/kg), and a GPER-1 antagonist (G-36; 0-80 μg/kg). To investigate possible cross-talk between ERα and GPER-1, we examined whether GPER-1 blockade affects the anorexigenic effect of PPT. Feeding was monitored in OVX rats that received s.c. injections of vehicle or 40 μg/kg G-36 followed 30 min later by s.c. injections of vehicle or 200 μg/kg PPT. Selective activation of ERα and GPER-1 alone decreased food intake within 1 h of drug treatment, and feeding remained suppressed for 22 h following PPT treatment and 4 h following G-1 treatment. Acute administration of G-36 alone did not suppress feeding at any time point. Blockade of GPER-1 attenuated PPT's rapid (within 1 h) anorexigenic effect, but did not modulate PPT's ability to suppress food intake at 2, 4 and 22 h. These findings demonstrate that selective activation of ERα produces a rapid (within 1 h) decrease in food intake that is best explained by a non-genomic signaling pathway and thus implicates the involvement of extra-nuclear ERα. Our findings also provide evidence that activation of GPER-1 is both sufficient to suppress feeding and necessary for PPT's rapid anorexigenic effect.

Estrogen-induced expression of tumor necrosis factor-like weak inducer of apoptosis through ERα accelerates the progression of lupus nephritis

OBJECTIVES

Oestrogens have been shown to play key roles in the pathogenesis of SLE. The aim of this study was to investigate the roles and mechanisms of 17β-estradiol (E2) in TNF-like weak inducer of apoptosis (TWEAK) expression in LN.

METHODS

Peripheral blood mononuclear cells (PBMCs) obtained from LN patients were used for in vitro experiments, while female MRL/lpr and MRL/MpJ mice were used for in vivo studies. E2, ICI 182 780 [estrogen receptor (ER)-selective antagonist], methyl-piperidino-pyrazole (MPP, ERα-selective modulator), lentivirus (LV)-TWEAK-short hairpin RNA (shRNA) and LV-control-shRNA treatments were used in this study.

RESULTS

TWEAK mRNA expression in PBMCs was significantly increased following E2 treatment and downregulated after incubation with ICI 182 780 or MPP. Compared with sham-operated MRL/lpr mice, ovariectomized mice, treated with dimethyl sulphoxide vehicle alone, showed lower expression levels of renal TWEAK mRNA and protein. The expression of both mRNA and protein in ovariectomized mice was upregulated after E2 treatment and downregulated after ICI 182 780 or MPP co-treatment. Severe renal damage was observed in E2-treated ovariectomized mice, as were higher serum levels of IL-6, compared with dimethyl sulphoxide vehicle-treated ovariectomized mice. Co-treatment with LV-TWEAK-shRNA reversed these changes, and LV-control-shRNA treatment had no effect on them.

CONCLUSION

Our results demonstrated that E2 plays an important role in the upregulation of TWEAK expression in LN, most likely through an ERα-dependent pathway, causing kidney damage. This provides a novel insight into the mechanisms of the E2-TWEAK signalling pathway in LN.

The Effects of Estrogen Receptors' Antagonist on Brain Edema, Intracranial Pressure and Neurological Outcomes after Traumatic Brain Injury in Rat

Background:

In previous studies, the neuroprotective effect of 17β-estradiol in diffuse traumatic brain injury has been shown. This study used ICI 182,780, a non-selective estrogen receptor antagonist, to test the hypothesis that the neuroprotective effect of 17β-estradiol in traumatic brain injury is mediated by the estrogen receptors.

Methods:

The ovariectomized rats were divided into eight groups. Brain injury was induced by Marmarou’s method. Estrogen was injected 30 minutes after traumatic brain injury, and ICI 182,780 was injected before traumatic brain injury and also before estrogen treatment. In one group only ICI 182,780 was injected. The brain water content and Evans blue dye content were measured 24 and 5 hours after traumatic brain injury, respectively. The neurologic outcomes and intracranial pressure were assessed before, 4, and 24 hours after traumatic brain injury.

Results:

Brain water content and Evans blue content were less in estrogen-treated group comparison to vehicle group. ICI 182,780 eliminated the effects of estrogen on brain edema and brain blood barrier permeability. Intracranial pressure was increased significantly after trauma, and estrogen decreased intracranial pressure at 4 and 24 hours after traumatic brain injury in comparison to vehicle. This inhibitory effect was also eliminated by treatment with ICI182,780. ICI 182,780 also inhibited the estrogen induced increase in neurologic outcomes following traumatic brain injury. However, the use of ICI 182,780 alone had no neuroprotective effect after traumatic brain injury.

Conclusion:

The results suggest that classical estrogen receptors have probably a role in the neuroprotective function of estrogen following traumatic brain injury.

ERβ decreases breast cancer cell survival by regulating the IRE1/XBP-1 pathway

Unfolded protein response (UPR) is an adaptive reaction that allows cancer cells to survive endoplasmic reticulum (EnR) stress that is often induced in the tumor microenvironment because of inadequate vascularization. Previous studies report an association between activation of the UPR and reduced sensitivity to antiestrogens and chemotherapeutics in estrogen receptor α (ERα)-positive and triple-negative breast cancers, respectively. ERα has been shown to regulate the expression of a key mediator of the EnR stress response, the X-box-binding protein-1 (XBP-1). Although network prediction models have associated ERβ with the EnR stress response, its role as regulator of the UPR has not been experimentally tested. Here, upregulation of wild-type ERβ (ERβ1) or treatment with ERβ agonists enhanced apoptosis in breast cancer cells in the presence of pharmacological inducers of EnR stress. Targeting the BCL-2 to the EnR of the ERβ1-expressing cells prevented the apoptosis induced by EnR stress but not by non-EnR stress apoptotic stimuli indicating that ERβ1 promotes EnR stress-regulated apoptosis. Downregulation of inositol-requiring kinase 1α (IRE1α) and decreased splicing of XBP-1 were associated with the decreased survival of the EnR-stressed ERβ1-expressing cells. ERβ1 was found to repress the IRE1 pathway of the UPR by inducing degradation of IRE1α. These results suggest that the ability of ERβ1 to target the UPR may offer alternative treatment strategies for breast cancer.

A single low dose of cadmium exposure induces benign prostate hyperplasia like condition in rat: A novel benign prostate hyperplasia rodent model

Abnormal prostate growth is the most prevalent pathological sign in aged human males, as reflected by high incidence of benign prostate hyperplasia (BPH) and prostate cancer. In spite of the high prevalence, the etiology and pathophysiology of BPH is unclear due to the lack of any established rodent model for study. It has been demonstrated that the cadmium (Cd) mimics the activity of androgen or estrogen by interacting with the steroid hormone receptors in the prostate and elicits BPH, but the specific receptor which binds to Cd is still unknown. Our lab studies with BPH patients highlighted a strong co-relation between smokings with increased Cd content. Changes in the maximum urinary flow rate (Qmax) and prostatic acid phosphatase (PAP) level further supports that Cd can induce BPH like condition. Therefore, the present study was aimed to induce BPH like condition in rats by Cd administration. The dose of cadmium was standardized in an age- and time-dependent manner, which was further examined by prostate weight, histology, and PAP levels that elucidated the pathogenesis of BPH. Further to understand the molecular basis, steroid hormone receptor antagonist experiment was performed. Gene expression and immunohistochemistry data suggest that Cd induces hyperplasia like condition by activating the androgen receptor and estrogen receptor-α and suppresses the action of estrogen receptor-β. The experimental model used here is a cost effective, less time consuming and potentially valuable tool for investigating the respective functions of epithelial and stromal hormone receptors. The applicability of this model would be helpful in understanding the pathogenesis of BPH and its progression.

Notoginsenoside R1 attenuates cardiac dysfunction in endotoxemic mice: an insight into oestrogen receptor activation and PI3K/Akt signalling

BACKGROUND AND PURPOSE

Notoginsenoside R1 (NG-R1), a novel phytoestrogen isolated from Panax notoginseng, is believed to have anti-inflammatory, anti-oxidative and anti-apoptotic properties. However, its cardioprotective properties and underlying mechanisms are largely unknown. Here we have assessed the contribution of the anti-inflammatory effects of NG-R1 to the amelioration of septic cardiac dysfunction and inflammation in mice.

EXPERIMENTAL APPROACH

We assessed cardiac function in mice by echocardiography. We studied the protein or mRNA levels of some inflammatory factors, apoptotic factors and oestrogen receptors (ERs) in heart tissues upon stimulation with bacterial LPS, NG-R1 or some pharmacological inhibitors.

KEY RESULTS

Six hours after LPS administration (10 mg·kg(-1) , i.p.) cardiac function was decreased, an effect attenuated by NG-R1 pretreatment (25 mg·kg(-1) ·d(-1) , i.p.). NG-R1 also improved the imbalance between iNOS and eNOS, prevented activation of NF-κB and the subsequent myocardial inflammatory and apoptotic responses in endotoxemic mice. The effects of NG-R1 were closely associated with activation of the oestrogen receptor ERα and of PI3K/PKB (Akt) signalling, as characterized by NG-R1-induced preservation in ERα, phospho-Akt, phospho-GSK3β and I-κBα, and of cardiac function that was partially blocked by selective inhibitors of ERα or PI3K. However, NG-R1 had no effect on LPS-activated TLR-4.

CONCLUSIONS AND IMPLICATIONS

NG-R1 is a promising compound for protecting the heart from septic shock, possibly via the activation of ERα and PI3K/Akt signalling. This mechanism produces blockade of NF-κB activation and attenuation of the pro-inflammatory state and apoptotic stress in the myocardium.

The role of S6K1 in ER-positive breast cancer

The 40S ribosomal S6 kinase 1 (S6K1) is a conserved serine/threonine protein kinase that belongs to the AGC family of protein kinases, which also includes Akt and many others. S6K1 is the principal kinase effector downstream of the mammalian target of rapamycin complex 1 (mTORC1). S6K1 is sensitive to a wide range of signaling inputs, including growth factors, amino acids, energy levels and hypoxia. S6K1 relays these signals to regulate a growing list of substrates and interacting proteins in control of oncogenic processes, such as cell growth and proliferation, cell survival and apoptosis and cell migration and invasion. Several lines of evidence suggest an important role for S6K1 in estrogen receptor (ER)-positive breast cancer. S6K1 directly phosphorylates and activates ERα. Furthermore, S6K1 expression is estrogenically regulated. Therefore, hyperactivation of mTORC1/S6K1 signaling may be closely related to ER-positive status in breast cancer and may be utilized as a marker for prognosis and a therapeutic target.

The conundrum of estrogen receptor oscillatory activity in the search for an appropriate hormone replacement therapy

By the use of in vivo imaging, we investigated the dynamics of estrogen receptor (ER) activity in intact, ovariectomized, and hormone-replaced estrogen response element-luciferase reporter mice. The study revealed the existence of a long-paced, noncircadian oscillation of ER transcriptional activity. Among the ER-expressing organs, this oscillation was asynchronous and its amplitude and period were tissue dependent. Ovariectomy affected the amplitude but did not suppress ER oscillations, suggesting the presence of tissue endogenous oscillators. Long-term administration of raloxifene, bazedoxifene, combined estrogens alone or with basedoxifene to ovariectomized estrogen response element-luciferase mice showed that each treatment induced a distinct spatiotemporal profile of ER activity, demonstrating that the phasing of ER activity among tissues may be regulated by the chemical nature and the concentration of circulating estrogen. This points to the possibility of a hierarchical organization of the tissue-specific pacemakers. Conceivably, the rhythm of ER transcriptional activity translates locally into the activation of specific gene networks enabling ER to significantly change its physiological activity according to circulating estrogens. In reproductive and nonreproductive organs this hierarchical regulation may provide ER with the signaling plasticity necessary to drive the complex metabolic changes occurring at each female reproductive status. We propose that the tissue-specific oscillatory activity here described is an important component of ER signaling necessary for the full hormone action including the beneficial effects reported for nonreproductive organs. Thus, this mechanism needs to be taken in due consideration to develop novel, more efficacious, and safer hormone replacement therapies.

The ovarian hormone estradiol plays a crucial role in the control of food intake in females

Despite a strong male bias in both basic and clinical research, it is becoming increasingly accepted that the ovarian hormone estradiol plays an important role in the control of food intake in females. Estradiol's feeding inhibitory effect occurs in a variety of species, including women, but the underlying mechanism has been studied most extensively in rats and mice. Accordingly, much of the data reviewed here is derived from the rodent literature. Adult female rats display a robust decrease in food intake during estrus and ovariectomy promotes hyperphagia and weight gain, both of which can be prevented by a physiological regimen of estradiol treatment. Behavioral analyses have demonstrated that the feeding inhibitory effect of estradiol is mediated entirely by a decrease in meal size. In rats, estradiol appears to exert this action indirectly via interactions with peptide and neurotransmitter systems implicated in the direct control of meal size. Here, I summarize research examining the neurobiological mechanism underlying estradiol's anorexigenic effect. Central estrogen receptors (ERs) have been implicated and activation of one ER subtype in particular, ERα, appears both sufficient and necessary for the estrogenic control of food intake. Future studies are necessary to identify the critical brain areas and intracellular signaling pathways responsible for estradiol's anorexigenic effect. A clearer understanding of the estrogenic control of food intake is prerequisite to elucidating the biological factors that contribute to obesity and eating disorders, both of which are more prevalent in women, compared to men.

Complete estrogen receptor blocker ICI182,780 promotes the proliferation of vascular smooth muscle cells

ICI182,780 is used in adjuvant therapies of breast cancer. As a complete estrogen receptor (ER) blocker, ICI182,780 may antagonize the effects of estrogen on the cardiovascular system. Estrogen inhibits the proliferation of vascular smooth muscle cells (VSMCs), which is one of the mechanisms that estrogen can exert cardioprotective effects. In the present study, to assess the effects of ICI182,780 on the proliferation of VSMCs, we cultured VSMCs isolated from rat aorta with or without the ER antagonist ICI182,780. The results of 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, bromodeoxyuridine incorporation assay, viable cell count, immunochemical staining for proliferating cell nuclear antigen (PCNA), and S-phase ratio determined by flow cytometry revealed a remarkable proliferation of VSMCs after ICI182,780 treatment. ICI182,780 significantly enhanced cell growth in a dose-dependent manner (10(-8)-10(-5) M). Furthermore, the number of PCNA-positive cells and the S-phase progression of VSMCs increased after treatment with ICI182,780. Reverse transcriptase-polymerase chain reaction (RT-PCR) and western blot analysis showed that the mRNA and protein level of cyclin D1 in VSMCs increased under the treatment of ICI182,780. These data suggested that ICI182,780 can promote the growth of VSMCs, which might produce some adverse effects on the cardiovascular system.

Activation of ERα is necessary for estradiol's anorexigenic effect in female rats

While there is considerable evidence that the ovarian hormone estradiol reduces food intake in female rats, it is unclear which estrogen receptor (ER) subtype, ERα or ERβ, mediates this effect. While several studies have demonstrated that activation of ERα, but not ERβ, is sufficient to reduce food intake in ovariectomized (OVX) rats, there are limited data regarding which receptor subtype is necessary. Here we used the selective ERα and ERß antagonists, MPrP and PHTPP, respectively, to investigate this question. We found that antagonism of ERα, but not ERβ, prevented the decrease in food intake following acute administration of estradiol in OVX rats. In addition, antagonism of ERα prevented the estrous-related, phasic reduction in food intake that occurs in response to the rise in circulating levels of estradiol in cycling rats. We conclude that activation of ERα is necessary for the anorexigenic effects of exogenous and endogenous estradiol in female rats.

Contrasting effects of different maternal diets on sexually dimorphic gene expression in the murine placenta

Diet during pregnancy influences the future health of a woman's offspring, with outcomes differing depending on the child's sex. Because the placenta buffers the fetus from the mother, we examined the impact of diet and fetal sex on placental gene expression in mice fed either a very-high-fat, low-fat, chow diet of intermediate caloric density. At day 12.5 of pregnancy, placental RNA was extracted and analyzed by microarray. The expression of 1,972 genes was changed more than 2-fold (P < 0.05) in comparisons across diet in at least one of the three groups. Female placentae demonstrated more striking alterations in gene expression in response to maternal diet than male placentae. Notably, each diet provided a distinctive signature of sexually dimorphic genes, with expression generally higher in genes (651 out of 700) from female placentae than those from male placentae. Several genes normally considered as characteristic of kidney function were affected by diet, including genes regulating ion balance and chemoreception. The placenta also expressed most of the known olfactory receptor genes (Olfr), which may allow the placenta to sense odorant molecules and other minor dietary components, with transcript levels of many of these genes influenced by diet and fetal sex. In conclusion, gene expression in the murine placenta is adaptive and shaped by maternal diet. It also exhibits pronounced sexual dimorphism, with placentae of females more sensitive to nutritional perturbations than placentae of males.

Effect of a putative ERalpha antagonist, MPP, on food intake in cycling and ovariectomized rats

Estrogens exert many of their behavioral effects by binding to nuclear estrogen receptor (ER) proteins, ERalpha and ERbeta. Recent studies involving ER knockout mice and selective ER agonists suggest that estradiol's anorexigenic effect is mediated via activation of ERalpha. To investigate this hypothesis, we examined whether the presumptive ERalpha antagonist, MPP, could block estradiol's anorexigenic effect. In the first series of experiments, the effects of MPP on food intake and uterine weight were monitored in ovariectomized (OVX) rats treated with either a physiological dose of estradiol benzoate (EB) or a selective ERalpha agonist (PPT). In the final experiment, food intake was monitored following acute administration of MPP in ovarian-intact (cycling) female rats. Contrary to our hypothesis, MPP failed to attenuate either EB's or PPT's ability to decrease food intake and increase uterine weight in OVX rats. However, in ovarian-intact rats, a similar regimen of MPP treatment attenuated the phasic decrease in food intake that is associated with estrus. We conclude that MPP may be a useful tool to investigate the behavioral actions of endogenous estradiol, but may have limited utility in studying the behavioral effects of exogenous estradiol in OVX rats.