Gisele Branchini

Reactive oxygen and nitrogen species balance in the determination of thyroid hormones-induced cardiac hypertrophy mediated by renin–angiotensin system

Role of reactive oxygen species (ROS)/nitric oxide (NO) balance and renin-angiotensin system in mediating cardiac hypertrophy in hyperthyroidism was evaluated in an in vivo and in vitro experimental model. Male Wistar rats were divided into four groups: control, thyroid hormone, vitamin E (or Trolox, its hydrosoluble analogue), thyroid hormone+vitamin E. Angiotensin II receptor (AT1/AT2) gene expression, immunocontent of AT1/AT2 receptors, angiotensinogen, NADPH oxidase (Nox2), and nitric oxide synthase isoforms, as well as ROS concentration (hydrogen peroxide and superoxide anion) were quantified in myocardium. Thyroid hormone increased ROS and NO metabolites, iNOS, nNOS and eNOS isoforms and it was accompanied by cardiac hypertrophy. AT1/AT2 expression and the immunocontent of angiotensinogen and Nox2 were enhanced by thyroid hormone. Antioxidants reduced ROS levels, Nox2, AT1/AT2, NOS isoforms and cardiac hypertrophy. In conclusion, ROS/NO balance may play a role in the control of thyroid hormone-induced cardiac hypertrophy mediated by renin-angiotensin system.

Human Granulosa Cells: Insulin and Insulin-Like Growth Factor-1 Receptors and Aromatase Expression Modulation by Metformin

Background/Aim: Granulosa cells are the source of the most important ovarian steroids. Even in patients without significant improvement in metabolic parameters, metformin has apparently an important effect on the ovary. The aim of this study was to evaluate gene and protein expression of an insulin receptor (IR), insulin-like growth factor-1 (IGF1) receptor (IGF1R) and aromatase in granulosa cells treated with metformin and insulin. Methods: Luteinized granulosa cells were collected from 27 patients during in vitro fertilization procedures. Cells were isolated, stored in culture for 24 h and divided into four groups: control; metformin for 30 min, and metformin for 30 min plus insulin for 30 or 60 min. Results: IR and IGF1R mRNA expression was significantly enhanced by metformin but was not affected by insulin. Aromatase mRNA expression was significantly reduced in metformin-incubated cells following stimulation with insulin for 30 min. No statistical differences were found in IGF1R and aromatase protein expression, and IR expression was not detected. Conclusion: A direct effect of metformin on the gene expression of IGF1R, IR and aromatase was observed. Further studies should investigate the role of IGF1R, IR and aromatase in ovarian physiology for a better understanding of the effect of metformin.

Effect of progesterone on the expression of GABA A receptor subunits in the prefrontal cortex of rats: implications of sex differences and brain hemisphere

Progesterone is a neuroactive hormone with non‐genomic effects on GABAA receptors (GABAAR). Changes in the expression of GABAAR subunits are related to depressive‐like behaviors in rats. Moreover, sex differences and depressive behaviors have been associated with prefrontal brain asymmetry in rodents and humans. Thus, our objective was to investigate the effect of progesterone on the GABAAR α1 and γ2 subunits mRNA expression in the right and left prefrontal cortex of diestrus female and male rats exposed to the forced swimming test (FST). Male and female rats (n = 8/group) were randomly selected to receive a daily dose of progesterone (0·4 mg·kg–1) or vehicle, during two complete female estrous cycles (8–10 days). On the experiment day, male rats or diestrus female rats were euthanized 30 min after the FST. Our results showed that progesterone significantly increased the α1 subunit mRNA in both hemispheres of male and female rats. Moreover, there was an inverse correlation between depressive‐like behaviors and GABAAR α1 subunit mRNA expression in the right hemisphere in female rats. Progesterone decreased the GABAAR γ2 mRNA expression only in the left hemisphere of male rats. Therefore, we conclude that the GABAA system displays an asymmetric distribution according to sex and that progesterone, at lower doses, presents an antidepressant effect after increasing the GABAAR α1 subunit expression in the right prefrontal cortex of female rats. Copyright

Ovarian steroid hormones modulate the expression of progesterone receptors and histone acetylation patterns in uterine leiomyoma cells

Abstract Uterine leiomyomas are the most common benign smooth muscle cell tumors in women. Estrogen (E2), progesterone (P4) and environmental factors play important roles in the development of these tumors. New treatments, such as mifepristone, have been proposed. We evaluated the gene expression of total (PRT) and B (PRB) progesterone receptors, and the histone acetyltransferase (HAT) and deacetylase (HDAC) activity after treatment with E2, P4 and mifepristone (RU486) in primary cell cultures from uterine leiomyoma and normal myometrium. Compared to myometrium, uterine leiomyoma cells showed an increase in PRT mRNA expression when treated with E2, and increase in PRB mRNA expression when treated with E2 and P4. Treatment with mifepristone had no significant impact on mRNA expression in these cells. The HDAC activity was higher in uterine leiomyoma compared to myometrial cells after treatment with E2 and E2 + P4 + mifepristone. HAT activity was barely detectable. Our results suggest that ovarian steroid hormones modulate PR, and mifepristone was unable to decrease PRT and PRB mRNA. The higher activity of HDAC leiomyoma cells could be involved in transcriptional repression of genes implicated in normal myometrium cell function, contributing to the maintenance and growth of uterine leiomyoma.

Androgen receptor isoforms expression in benign prostatic hyperplasia and primary prostate cancer

The role of molecular changes in the androgen receptor (AR) as AR variants (AR-Vs) is not clear in the pathophysiology of benign prostatic hyperplasia (BPH) and hormone-naïve PCa. The aim of the current work was to identify the presence of AR isoforms in benign tissue and primary PCa, and to evaluate the possible association with tumor aggressiveness and biochemical recurrence in primary PCa. The mRNA levels of full length AR (AR-FL) and AR-Vs (AR-V1, AR-V4 and AR-V7) were measured using RT-qPCR. The protein expression of AR-FL (AR-CTD and AR-NTD) and AR-V7 were evaluated by the H-Score in immunohistochemistry (IHC). All investigated mRNA targets were expressed both in BPH and PCa. AR-FL mRNA levels were similar in both groups. AR-V4 mRNA expression showed higher levels in BPH, and AR-V1 and AR-V7 mRNA expression were higher in PCa. The AR-V7 protein showed a similar H-Score in both groups, while AR-CTD and AR-NTD were higher in nuclei of epithelial cells from BPH. These results support the assumption that these constitutively active isoforms of AR are involved in the pathophysiology of primary PCa and BPH. The role of AR-Vs and their possible modulation by steroid tissue levels in distinct types of prostate tumors needs to be elucidated to help guide the best clinical management of these diseases.

Androgenic modulation of AR-Vs

PurposeThe importance of androgen receptor variants (AR-Vs) is recognized in prostate cancer. AR-Vs have been the focus of many studies. Expression of AR-Vs has been proposed as a biomarker for resistance to androgen deprivation therapy for metastatic disease. Herein, we show dynamic changes in AR-Vs expression in response to androgen modulation.MethodsThe C4-2B cell line was exposed to low (10−13 M) and high (10−8 M) androgen (dihydrotestosterone, DHT) levels, with or without flutamide. mRNA and protein expression levels were assessed by qPCR and immunohistochemistry, respectively.ResultsWe demonstrated that high levels of DHT downregulate AR-FL and AR-Vs. Even though AR-Vs did not present ligand-binding domain, thus were not capable of binding to DHT, they present dynamic changes under androgen treatment. Treatment with flutamide alone or in association with low levels of DHT stimulates growth of prostatic cells.ConclusionsImportantly, we provide evidence that AR-Vs respond differently to androgenic modulation. These findings have implications for a better understanding of the role of AR-Vs in prostate carcinogenesis.