Increased Aromatase Expression Research Articles

FRI026 PPARγ Antagonists Induce Aromatase Transcription In Human Adipose Tissue Cells

Abstract Disclosure: J. Ardenkjær-Skinnerup: None. P.S. Petersen: None. N. Hadrup: None. G. Ravn-Haren: None. B. Emanuelli: None. U.B. Vogel: None. K.A. Brown: None. Peroxisome proliferator-activated receptor gamma (PPARγ) activation in adipose stromal cells (ASCs; adipocyte precursors) is associated with decreased expression of the estrogen biosynthetic enzyme, aromatase, encoded by the CYP19A1 gene. A number of chemicals and endocrine disruptors can affect PPARγ function. For example, ethanol-mediated inhibition of PPARγ activity is associated with increased risk of breast cancer,1 and a potential mechanism has been suggested to involve upregulation of aromatase. It is therefore hypothesized that inhibitors of PPARγ will induce aromatase expression and may act as breast carcinogens. This study aimed to explore the effect of PPARγ antagonists on the expression of aromatase in cells from human adipose tissue. Human adipose tissue was obtained from abdominoplasty or reduction mammoplasty surgeries. Explants, adipocytes and ASCs were collected for culture and/or gene expression analysis. Primary ASCs and the hTERT A41 hWAT ASC line were differentiated in the presence of PPARγ antagonists followed by gene expression analysis or lipid staining. Adipose tissue explants and A41 cells were treated for 24 or 48 h with PPARγ agonist or antagonist, and gene expression analysis was performed. Finally, PPARγ was overexpressed in A41 cells and/or treated with a PPARγ agonist to study the effect of PPARγ protein level and activation on aromatase expression. Aromatase expression was higher in human ASCs than in mature adipocytes. Exposure of ASCs to PPARγ antagonists during differentiation inhibited lipid accumulation and resulted in higher expression of aromatase. PPARγ overexpression and agonist treatment repressed aromatase expression in A41 cells, while antagonist treatment in differentiated A41 cells resulted in increased aromatase expression. A similar tendency was observed in adipose tissue explants. In conclusion, the results suggest that PPARγ regulates aromatase through two separate mechanisms. Exposure of human ASCs to PPARγ antagonists indirectly upregulates aromatase expression by inhibition of adipogenesis. In addition, PPARγ regulates aromatase in differentiated ASCs via a more acute mechanism, not related to adipocyte differentiation. 1. Petersen RK, Larsen SB, Jensen DM, et al. PPARgamma-PGC-1alpha activity is determinant of alcohol related breast cancer. Cancer Lett. 2012;315(1):59-68. Presentation: Friday, June 16, 2023

Mammary gland development in male rats perinatally exposed to propiconazole, glyphosate, or their mixture

This study aimed to assess whether perinatal exposure to propiconazole (PRO), glyphosate (GLY) or their mixture (PROGLY) alters key endocrine pathways and the development of the male rat mammary gland. To this end, pregnant rats were orally exposed to vehicle, PRO, GLY, or a mixture of PRO and GLY from gestation day 9 until weaning. Male offspring were euthanized on postnatal day (PND) 21 and PND60. On PND21, GLY-exposed rats showed reduced mammary epithelial cell proliferation, whereas PRO-exposed ones showed increased ductal p-Erk1/2 expression without histomorphological alterations. On PND60, GLY-exposed rats showed reduced mammary gland area and estrogen receptor alpha expression and increased aromatase expression, whereas PRO-exposed ones showed enhanced lobuloalveolar development and increased lobular hyperplasia. However, PROGLY did not modify any of the endpoints evaluated. In summary, PRO and GLY modified the expression of key molecules and the development of the male mammary gland individually but not together.

Disruption of the developmental programming of the gonad of the broad snouted caiman (Caiman latirostris) after in ovo exposure to atrazine.

Environmental exposure to agrochemicals during early stages of development can induce subtle alterations that could permanently affect normal physiology. Previously, we reported that in ovo exposure to atrazine (ATZ) disrupts testicular histoarchitecture in postnatal caimans (Caiman latirostris). To assess whether such alterations are the result of disruption of gonadal developmental programming, this study aimed to evaluate the expression of histofunctional biomarkers (VASA, ER, PR, PCNA, and aromatase) and genes involved in gonadal development and differentiation (amh, sox-9, sf-1 and cyp19-a1) in the gonads of male and female caiman embryos and to assess the effect of ATZ exposure on these biomarkers and genes in the gonads of male embryos. Our results suggest that amh, aromatase and sox-9 play a role in sex determination and gonadal differentiation. In male caiman embryos, ATZ exposure increased aromatase expression and altered the temporal expression pattern of amh and sox-9 evidencing an ATZ-induced disruption of gonadal developmental programming. Since the effects of ATZ are consistent across all vertebrate classes, the ATZ-mediated disruptive effects here observed could be present in other vertebrate species.

Heat stress upregulates aromatases expression through nuclear DAX-1 deficiency in R2C Leydig tumor cells

An appropriate balance between testicular testosterone and estradiol is required for spermatogenesis. Excess estradiol is often identified in the semen and serum of infertile men; however, the mechanisms behind this observation remain unclear. This study indicates the relationship between heat stress and aromatase synthesis in Leydig cells. We used R2C rat Leydig tumor cells, which can synthesize both testosterone and estradiol. Aromatase transcription was regulated by the PⅡ promoter with or without heat stress. Heat stress at 40 °C increased aromatase expression and decreased testosterone to estradiol ratio and nuclear DAX-1 (dosage-sensitive sex reversal, adrenal hypoplasia critical region, on chromosome X, gene 1), which is a suppressor of steroidogenic factor 1 (SF-1). Leptomycin B and KPT-185, a nuclear export inhibitor, prevented nuclear DAX-1 deficiency induced by heat stress and inhibited aromatase transcription. These results indicate that heat stress interferes with DAX-1–SF-1 interaction and induces SF-1-dependent aromatase transcription.

Bisphenol A exposures and hormone concentrations in a cohort of women receiving aromatase inhibitor therapy for breast cancer.

e12535 Background: Bisphenol A (BPA), a widely used chemical in plastics production, has been shown to have estrogenic activity, although it is unclear whether BPA exposure alters effectiveness of aromatase inhibitor (AI) treatment among women with breast cancer. In vitro studies have indicated that at higher concentrations (≥10-4 μM), BPA inhibits aromatase expression and activity, whereas at environmentally relevant concentrations (≤10-8 μM), BPA increases aromatase expression and activity. Few in vivo studies have investigated the association between BPA exposure and estrogen concentrations among non-pregnant women. This pilot study among post-menopausal women receiving AI therapy evaluated whether BPA is detectable in participants’ urine, and the association between BPA and hormone concentrations. Methods: This study was ancillary to a larger intervention study (ClinicalTrials.gov NCT01509079), and participants provided informed consent for this ancillary study under a protocol approved by the institutional review boards of Park Nicollet Institute/HealthPartners and the University of Minnesota. AI adherence during the 4 weeks prior to the baseline visit was monitored through weekly diaries. Participants were instructed to collect spot urine collections in sterile, BPA-free polypropylene containers in the 24 hours prior to the baseline study visit. Serum hormone concentrations were measured using serum collected at the baseline study visit. The Breast Cancer Prevention Trial - Musculoskeletal Symptom (BCPT-MS) scale was used to assess AI-associated musculoskeletal syndrome symptoms at the baseline study visit. Results: Fourteen women agreed to participate in the pilot study, however one participant’s data was excluded due to substances interfering with BPA measurement. BPA was detected in urine from all 13 remaining participants. Geometric mean urinary BPA concentration (1.55 mcg/g creatinine, 95% confidence interval (CI): 0.98-2.45) was higher than concentrations reported for females (1.36 mcg/g creatinine, 95% CI: 1.23-1.51) in the 2013-14 National Health and Nutrition Examination Survey biomonitoring data. Age, body mass index, and percent body fat did not differ between women above or below the study median urinary BPA concentrations (1.49 ng/mL). Women with BPA concentrations >1.49 ng/mL had consistently lower serum estrone (5.0 vs. 7.0 pg/mL, p=0.15), estradiol (2.8 vs. 3.6 pg/mL, p=0.04), and testosterone (21.5 vs 23.8 ng/dL, p=0.28) concentrations compared to women with lower BPA concentrations. No statistically significant differences in BCPT-MS scores were observed between women with higher vs. lower urinary BPA concentrations. Conclusions: These preliminary findings suggest that BPA exposures may work in concert with AIs to lower serum estrogen levels. However, further research is needed to confirm these findings.

Type I IFN stimulates IFI16-mediated aromatase expression in adipocytes that promotes E2-dependent growth of ER-positive breast cancer

Although type I interferons (IFNs) play multifaceted roles during tumorigenesis and cancer treatment, the interplay between type I IFNs and estrogen signaling in breast cancer (BC) microenvironment is not well understood. Here, we report a novel function of type I IFNs in inducing aromatase expression in adipose tissues surrounding BC, which potentiates the E2-dependent growth of estrogen receptor (ER)-positive BC. First, we found that expression levels of type I IFNs correlate negatively with clinical outcome but positively with tumor grade in patients with ER-positive BC. Levels of type I IFNs were elevated in cocultured media of immune cells and BC cells, which increased aromatase expression and E2 production in Simpson–Golabi–Behmel syndrome preadipocytes. The type I IFN-induced aromatase expression was dependent on IFN-γ-inducible protein 16 (IFI16), which is encoded by an interferon-stimulated gene. At the molecular level, type I IFNs led to recruitment of HIF1α–IFI16–PRMT2 complex to the hypoxia-response element located in the aromatase PI.3/PII promoter. Next, we generated an adipocyte-specific Ifi204, which is a mouse ortholog of human IFI16, knockout mouse (Ifi204-AKO). IFNβ induced E2 production in the preadipocytes isolated from the control mice, but such E2 production was far lower in the Ifi204-AKO preadipocytes. Importantly, the growth of orthotopically inoculated E0771 ER-positive mammary tumors was reduced significantly in the Ifi204-AKO mice. Taken together, our findings provide novel insights into the crosstalk between type I IFNs and estrogen signaling in the progression of ER-positive BC.

MicroRNA-21 enhances estradiol production by inhibiting WT1 expression in granulosa cells.

In antral follicles, the transition of proliferative granulosa cells to estradiol-producing is critical for proper oocyte maturation. MicroRNAs are noncoding RNAs that play important roles in ovarian follicular development; however, this has yet to be fully characterized. MicroRNA-21 is significantly higher in granulosa cells isolated from large antral follicles compared to those from small antral follicles. To investigate the function of miR-21, porcine granulosa cells were transfected with miR-21 mimic or miR-21 targeted siRNA. Cells with the miR-21 mimic had higher aromatase expression and estradiol production but decreased WT1 expression. Conversely, cells with the miR-21 siRNA secreted less estradiol and had higher WT1 expression. We hypothesized that miR-21 promotes estradiol production by inhibiting WT1 protein synthesis. We found a potential miR-21 binding site in the 3'UTR of the WT1 transcript and performed a dual-luciferase reporter assay using the WT and mutated 3'UTR. Compared to the negative control, the miR-21 mimic induced a significant decrease in luciferase activity in the WT 3'UTR. This decrease was reversed when the 3'UTR was mutated, suggesting miR-21 targets this site to inhibit WT1 expression. We next transfected porcine granulosa cells with WT1 targeted siRNA and observed a significant increase in aromatase expression and estradiol secretion. We propose that miR-21 represses WT1 expression in granulosa cells to potentially promote aromatase expression and estradiol production. This study offers the first report of a microRNA regulating WT1 expression in granulosa cells and reveals the role of miR-21 in WT1's regulation of estradiol production.

Increased P450 aromatase levels in post-menopausal women after acute ischemic stroke

BackgroundSex differences in stroke have been attributed to the neuroprotective effects of estrogen, yet most clinical trials of estrogen supplementation for stroke prevention have failed. The contribution of sex hormones to stroke outcome remains a subject of debate. Aromatization of testosterone to estradiol in neural tissue leads to sexual differentiation. Emerging data suggests aromatase activity increases in response to brain injury, and increased aromatase expression is seen in the ischemic penumbra in animal models. The objective of this study was to examine the levels of endogenous sex steroids after acute ischemic stroke and determine if levels of sex steroids were associated with acute stroke outcomes.MethodsPeripheral blood from ischemic stroke patients and controls was collected under an approved IRB within 24 h of symptom onset. 17β-estradiol, testosterone, and aromatase levels were measured in the serum of both men and women using ELISA. Hormone levels were compared in men vs. women in stroke and control groups and correlated with outcomes (NIHSS and change in the modified Rankin Scale (mRS), defined as the difference of premorbid and discharge mRS) using multivariate regression.ResultsWe found no significant difference in estradiol levels 24 h after stroke in men (p = 0.86) or women (p = 0.10). In men, testosterone significantly decreased after stroke as compared with controls (1.83 ± 0.12 vs. 2.86 ± 0.65, p = 0.01). Aromatase levels were significantly increased in women after stroke as compared with controls (2.27 ± 0.22 vs. 0.97 ± 0.22, p = 0.002), but not in men (p = 0.84). Estradiol levels positively correlated with change in mRS in both women (r = 0.38, p = 0.02) and men (r = 0.3, p = 0.04).ConclusionsEstradiol levels correlated with functional outcomes (change in mRS) in both men and women, at least in the acute phase (24 h) of stroke. However, no significant difference in estradiol levels is seen 24 h post-stroke in men or women. Testosterone levels decrease at 24 h after stroke in men. As seen in animal models, aromatase levels increase after acute ischemic stroke, but this was only true for women. These indicate an active aromatization process in post-menopausal women after acute ischemic stroke.

Long non-coding RNA TUG1 and its molecular mechanisms in polycystic ovary syndrome

ABSTRACT Polycystic ovary syndrome (PCOS) causes anovulatory infertility in women of reproductive age, but etiopathogenesis of PCOS remains undetermined. Taurine up-regulated 1 (TUG1), an evolutionarily conserved long non-coding RNA, performs various biological functions; however, the role of TUG1 in PCOS remains unclear. Herein, TUG1 expression was assayed in granulosa cells (GCs) of 100 patients with PCOS and 100 control participants. Receiver operating characteristic (ROC) curve analysis was conducted to determine the diagnostic value of TUG1 in PCOS. TUG1 expression was also silenced in KGN cells to explore the role of TUG1 in cellular proliferation, apoptosis, cell-cycle progression, autophagy, and steroidogenesis. We found that TUG1 levels were dramatically increased in the PCOS group compared with those of the control group; this increased expression was related to a rising antral follicle count (R = 0.209, P < 0.001 versus control). The ROC curve indicated a significant separation between PCOS group and the control group (AUC: 0.702; 95% CI: 0.630–0.773; P < 0.001). TUG1 showed a predominantly nuclear localization in human GCs. TUG1 knockdown reduced cellular proliferation, and promoted MAPKs pathway-dependent apoptosis and P21-dependent autophagy, but may not affect cell-cycle progression. TUG1 knockdown increased aromatase expression and oestradiol biosynthesis. Our results indicate that increased TUG1 expression in PCOS GCs may contribute to excessive follicular activation and growth, and may disrupt the selection of dominant follicle. Our study shows that TUG1 can be used as a diagnostic biomarker for PCOS.

Long Noncoding RNA HUPCOS Promotes Follicular Fluid Androgen Excess in PCOS Patients via Aromatase Inhibition.

Androgen excess is a key feature of polycystic ovary syndrome (PCOS), but the underlying molecular mechanism remains unclear. To determine the role and mechanism of novel long noncoding RNA (lncRNA) highly up-regulated in PCOS (HUPCOS) in the androgen excess of PCOS patients. The lncRNA expression profile in granulosa cells derived from PCOS and non-PCOS women were analyzed by using microarray assay. Human granulosa cell line KGN was used for mechanism investigation. This was a university-based study. Thirty-eight PCOS and 38 control patients were recruited: 8 PCOS and 8 control samples used for microarray discovery, the remaining 30 PCOS cases and 30 controls for quantitative RT-PCR validation. The aberrant expression lncRNA profile of PCOS patients was measured using microarray. The relationship of HUPCOS and follicular fluid testosterone was measured. Aromatase expression were analyzed after HUPCOS downregulation. HUPCOS interaction protein was confirmed by RNA pull-down. The significantly elevated lncRNA in PCOS granulosa cells was named HUPCOS, which was positively correlated with follicular fluid testosterone of PCOS patients. HUPCOS downregulation increased aromatase expression and promoted conversion of androgen to estrogen. RNA-binding protein with multiple splicing (RBPMS) was the most likely protein that combined with HUPCOS. Our findings suggested that HUPCOS mediated androgen excess in follicular fluid of PCOS patients by suppressing aromatase expression via interaction with RBPMS.

Aromatase-induced endogenous estrogen promotes tumour metastasis through estrogen receptor-α/matrix metalloproteinase 12 axis activation in castration-resistant prostate cancer.

Castration-resistant prostate cancer (CRPC) following androgen deprivation therapy remains a major obstacle advanced prostate cancer management. Aromatase catalyzes estrogen from androgens, yet the role of aromatase-generated endogenous estrogen in CRPC is poorly understood. In this study, we assessed the expression and function of aromatase in CRPC. We found that aromatase expression was significantly increased in CRPC tissues and cell lines. In some prostate cancer cell lines, aromatase was predominantly expressed in CD44+ subsets. Bicalutamide treatment significantly increased aromatase expression, and CYP19A1 expression positively correlated with estrogen responses and epithelial-mesenchymal transition. Aromatase knockdown in PC3 cells reduced invasiveness and decreased metastasis-related gene expression. The aromatase inhibitor, letrozole, attenuated tumour metastasis in castrated PC3-xenograft mice. Mechanistically, aromatase-induced endogenous estrogen promoted estrogen receptor-α (ERα) binding to matrix metalloproteinase 12 (MMP12) promoter estrogen response element (ERE). MMP12 co-localized with CD44 on the cell membrane and MMP12 knockdown significantly reduced estradiol-induced PC3 invasion. Taken together, our findings indicated that increased endogenous estrogen, catalysed by elevated aromatase levels, enhanced MMP12 expression via ERα, participated in CRPC progression and promoted tumour metastasis. Thus, aromatase represents a potential novel therapeutic target for CRPC.

Amplified Crosstalk Between Estrogen Binding and GFR Signaling Mediated Pathways of ER Activation Drives Responses in Tumors Treated with Endocrine Disruptors.

The pharmaceutical development of endocrine disruptors could not achieve appropriate advances in the field of anticancer fight. Considerations on the principles of currently used endocrine therapies. Comparison of the results of genetic studies being performed on breast cancer cells treated with estrogens, synthetic estrogens and antiestrogens. In breast cancer cells, increased estrogen concentrations amplify ER-signaling via a synergistic upregulation of both liganded and unliganded ER-activations and increased aromatase expression. The higher the upregulation of ER-signaling, the stronger is the tumor response. Low doses of synthetic estrogens exert an inhibition on the ligand-independent AF1-domain in breast cancer cells, while provoke compensatory activation on the superior, ligand-dependent AF2-domain of ERs and estrogen synthesis. Conversely, high doses of synthetic estrogens induce uncompensated genome-wide disruption in ER-regulated genes leading to toxic symptoms and unpredictable tumor responses. Treatment with antiestrogens, either ER-blockers or aromatase inhibitors, obstructs the crucial AF2-domain of ERs strongly deteriorating the activation of genomic machinery. Tumor responses to antiestrogen treatment depend on the compensatory activation of ER-signaling and the restoration of genomic stability. Recent patents provide methods for the conversion of ER-negative cancers to ER-positive ones improving the possibility of successful treatment. In tumor cells, the stabilization of genomic machinery and self-directed death may be achieved via a balanced activation of the AF1 and AF2 domains of ERs by natural estrogen treatment. In contrast, the blockade of either AF1 or AF2 domain by endocrine disruptors leads to toxic symptoms and unforeseeable tumor responses.

Expression of aromatase in tumor related stroma is associated with human bladder cancer progression

ABSTRACT Putative gender differences in bladder cancer (BCa) have been proposed to result from sex hormone influence. Aromatase is the key enzyme catalyzing the conversion of androgens to estrogens which may result in an intratumoral microenviroment with increased estrogen production. In this study, we investigated the expression pattern of aromatase and its association with BCa progression. Tissue samples from 88 BCa patients who underwent cystectomy were obtained. Using immunohistochemistry (IHC), expression of aromatase in tumor epithelium (TE) and tumor related stroma (TS) were evaluated separately, and the association of aromatase expression status with pathologic variables and overall survival (OS) outcome was examined. High aromatase expression was found in 33/88 (37.5%) of TE and in 65/88 (73.9%) of TS. Increased aromatase expression in TE had a trend to correlate with male gender. Increased aromatase in TS was significantly associated with adverse pathologic variables including higher pathologic pT, positive lymph node metastasis (pN), lymphovascular invasion (LVI), and distant metastasis. In univariate analysis, high aromatase expression in TS was significantly associated with poorer overall survival (p = 0.014), but this association was not significant (p = 0.163) in multivariate cox analysis adjusted for independent factors including age at surgery and pN. These results demonstrate that aromatase expression in TS but not TE may play a critical role in BCa progression. Our findings provide direct evidence of aromatase involvement in BCa and suggest endocrine therapy may have a potential role in the treatment of BCa.

Atrazine affects the morphophysiology, tissue homeostasis and aromatase expression in the efferent ductules of adult rats with mild alterations in the ventral prostate

The widely used herbicide atrazine is a potent endocrine disruptor known to cause increased aromatase expression and transient increase in testicular weight followed by remarkable testis atrophy. However, whether the effects of atrazine on the testes are primary or secondary to dysfunctions in other components of male reproductive tract remains unknown. Given the high sensitivity of the efferent ductules to estrogen imbalance and the similarity to alterations previously described for other disruptors of these ductules function, and the testicular alterations observed after atrazine exposure, we hypothesized that the efferent ductules could be a target for atrazine. Herein we characterized the efferent ductules and the ventral prostate of adult Wistar rats treated with 200 mg/kg/day of atrazine for 7, 15, and 40 days. Additionally, we evaluated if the effects of atrazine in these organs could be reduced after discontinuation of the treatment. Atrazine exposure resulted in mild effects on the ventral prostate, but remarkable alterations on the efferent ductules, including luminal dilation, reduced epithelial height, and disruption of the epithelial homeostasis, which coincides with increased aromatase expression. Together with our previous data, these results suggest that at least part of the testicular effects of atrazine may be secondary to the alterations in the efferent ductules.

Aromatase and neuroinflammation in rat focal brain ischemia

Accumulating evidence suggests that expression of aromatase, the enzyme responsible for the conversion of androgens to estrogens, is transiently upregulated in rat stroke models. It was further suggested that increased aromatase expression is linked to neuroinflammation and that it is neuroprotective in females. Our goal was to investigate aromatase upregulation in male rats subjected to experimental stroke in relationship to neuroinflammation, infarct and response to treatment with different putative neuroprotective agents. Intact male rats were subjected to transient (90min) middle cerebral artery occlusion (MCAO) and administered selfotel (N-methyl-d-aspartic acid (NMDA) receptor competitive antagonist), TPEN (a zinc chelator), a combination of the two drugs or vehicle, injected immediately after reperfusion. Animals were killed 14days after MCAO and consecutive brain sections used to measure aromatase expression, cerebral infarct volume and neuroinflammation. Quantitative immunohistochemistry (IHC) demonstrated increased brain aromatase expression in the peri-infarct area relative to contralesional area, which was partially abrogated by neuroprotective agents. There was no correlation between aromatase expression in the peri-infarct zone and infarct volume, which was reduced by neuroprotective agents. Microglial activation, measured by quantitative autoradiography, was positively correlated with infarct and inversely correlated with aromatase expression in the peri-infarct zone. Our findings indicate that focal ischemia upregulates brain aromatase in the male rat brain at 14days post surgery, which is within the time frame documented in females. However, the lack of negative correlation between aromatase expression and infarct volume and lack of positive correlation between microgliosis and aromatase do not support a major role for aromatase as a mediator of neuroprotection or a causal relationship between microglial activation and increased aromatase expression in male focal ischemia.

Persistent testicular structural and functional alterations after exposure of adult rats to atrazine

Atrazine is an endocrine disruptor affecting testicular steroidogenesis, and promoting testicular atrophy and 3β-HSD reduction. However, it remains unknown whether these effects are reversible or permanent. To address this issue was the aim of this study. Exposition of rats to 200mg/kg of atrazine resulted in transient increase in testicular weight, seminiferous tubules dilation and atrophy, and reduction in Leydig cell 3β-HSD. Testicular atrophy and 3β-HSD reduction were more pronounced after the recovery period of 75days. There was increase in aromatase expression after long-term exposure but it returned to control level after recovery. Moreover, there was increase in ED1−/ED2+, ED1+/ED2+ and ED1+/ED2− macrophages, in the recovery group. These macrophages were positive for 3β-HSD, thereby raising possibility of their involvement in steroidogenesis. These findings further emphasize the adverse effects of atrazine on male reproduction, highlighting that testicular damages may be irreversible even after a recovery period longer than the spermatogenic cycle.

Aromatase Blockade Is Associated With Increased Mortality in Acute Illness in Male Mice.

Context:The increase in circulating estrogen levels with acute illness in humans is accompanied by increased aromatase expression in adipose tissue and increased peripheral aromatization of estrogens to androgens. Animal studies indicate that estrogen may be beneficial in acute illness.Objective:We hypothesized that blockade of aromatase in acute illness would decrease survival.Design:Prospective sham controlled.Setting:Maine Medical Center Research Institute animal facility.Animals:Six- to 8-week-old male black 6 mice.Intervention:Mice underwent cecal ligation and puncture (CLP) to induce acute illness and were administered letrozole to block aromatase or saline. Mice undergoing sham surgery with or without letrozole served as controls. Adipose and cardiovascular tissue was harvested for preliminary evaluation of aromatase expression.Main outcome measurements:Survival was the main outcome measurement. Evidence for aromatase expression in tissue samples was assessed using western blot and/or immunohistochemistry.Results:With aromatase blockade, survival in CLP mice was decreased (P = 0.04). The presence of aromatase in adipose tissue was observed by western blot in CLP but not control mice. Similarly, the presence of aromatase was observed in cardiac tissue of CLP but not in control mice.Conclusions:The decreased survival during sepsis with aromatase blockade suggests that this response to acute illness may be important both physiologically and clinically. The preliminary observation of aromatase expression in adipose and cardiovascular tissue during acute illness in this mouse model indicates that this model has parallels to human physiology and may be useful for further studying the aromatase response to acute illness.

Leptin induces CREB-dependent aromatase activation through COX-2 expression in breast cancer cells

Leptin plays a key role in the control of adipocyte formation, as well as in the associated regulation of energy intake and expenditure. The goal of this study was to determine if leptin-induced aromatase enhances estrogen production and induces tumor cell growth stimulation. To this end, breast cancer cells were incubated with leptin in the absence or presence of inhibitor pretreatment, and changes in aromatase and cyclooxygenase-2 (COX-2) expression were evaluated at the mRNA and protein levels. Transient transfection assays were performed to examine the aromatase and COX-2 gene promoter activities and immunoblot analysis was used to examine protein expression. Leptin induced aromatase expression, estradiol production, and promoter activity in breast cancer cells. Protein levels of phospho-STAT3, PKA, Akt, ERK, and JNK were increased by leptin. Leptin also significantly increased cAMP levels, cAMP response element (CRE) activation, and CREB phosphorylation. In addition, leptin induced COX-2 expression, promoter activity, and increased the production of prostaglandin E2. Finally, a COX-2 inhibitor and aromatase inhibitor suppressed leptin-induced cell proliferation in MCF-7 breast cancer cells. Together, our data show that leptin increased aromatase expression in breast cancer cells, which was correlated with COX-2 upregulation, mediated through CRE activation and cooperation among multiple signaling pathways.

A novel action of follicle-stimulating hormone in the ovary promotes estradiol production without inducing excessive follicular growth before puberty

In cyclic females, FSH stimulates ovarian estradiol (E2) production and follicular growth up to the terminal stage. A transient elevation in circulating FSH and E2 levels occurs shortly after birth. But what could be the action of FSH on the ovary during this period, and in particular how it stimulates ovarian steroidogenesis without supporting terminal follicular maturation is intriguing. By experimentally manipulating FSH levels, we demonstrate in mice that the mid-infantile elevation in FSH is mandatory for E2 production by the immature ovary, but that it does not stimulate follicle growth. Importantly, FSH increases aromatase expression to stimulate E2 synthesis, however it becomes unable to induce cyclin D2, a major driver of granulosa cell proliferation. Besides, although FSH prematurely induces luteinizing hormone (LH) receptor expression in granulosa cells, LH pathway is not functional in these cells to induce their terminal differentiation. In line with these results, supplying infantile mice with a superovulation regimen exacerbates E2 production, but it does not stimulate the growth of follicles and it does not induce ovulation. Overall, our findings unveil a regulation whereby high postnatal FSH concentrations ensure the supply of E2 required for programming adult reproductive function without inducing follicular maturation before puberty.

Steroidogenic enzyme expression in estrogen production in the goat gastrointestinal (GI) tract and the effect of castration.

Extragonadal tissues are known to produce estrogens. At these sites, the C19 precursor is important for aromatase expression for the production of estrogen. Aromatase expression is tissue-specific and is controlled by hormones. Recent studies have shown that rat gastric parietal cells expressed aromatase. Our first objective was to investigate steroidogenic enzyme expression in estrogen biosynthesis; the second objective was to investigate which site(s) of the GI tract expressed steroidogenic enzymes; and the third objective was to assess the effects of castration on steroidogenic enzyme expression. CYP19A1, 17β-HSD3, CYP17A1, 3β-HSD and P450scc were quantified in the GI tract by real-time PCR. CYP19A1 was detected mainly in the body and pyloric regions of the abomasum, while we detected weak expression of CYP19A1 in other parts of GI tract. In addition, the expression of 17β-HSD3 and CYP17A1 was detected in abomasum. 3β-HSD expression was observed in duodenum and jejunum, while P450scc was not detectable in any part of GI tract. Immunohistochemical results showed immunolocalization of aromatase in parietal cells. Aromatase expression was observed to increase after castration. Furthermore, immunohistochemical results demonstrated that parietal cells also produced luteinizing hormone receptor (LHR). These results indicate steroidogenic enzymes required for the biosynthesis of estrogen were expressed, and the abomasum appeared to be the responsible organ for estrogen biosynthesis in the goat GI tract. In addition, parietal cells were responsible for estrogen production and the expression of LHR. Castration increased aromatase expression in abomasum through LH mediation.