The Emerging Role of FOXL2 in Regulating the Transcriptional Activation Function of Estrogen Receptor ß: An Insight Into Ovarian Folliculogenesis.

Germline mutations of the fork-head transcriptional factor forkhead box L2 (FOXL2) predispose embryos to autosomal-dominant blepharophimosis-ptosis-epicanthus inversus syndrome with primary ovarian insufficiency in female patients, but the mechanisms of FOXL2 in ovarian follicular development remain elusive. Estrogens produced by ovarian granulosa cells and estrogen receptor (ER) α and ERß play fundamental roles in ovarian pathophysiology, and a previous study revealed that ERα and ERß physically interact with FOXL2. However, the underlying functions of these interactions have not been investigated. Herein, we report an ERß-specific repressive function of FOXL2. Histological examination demonstrated that FOXL2 expression tends to be intense during early follicular development. Immunoprecipitation revealed that ERß and FOXL2 interact in a ligand-independent manner. In vitro pull-down assays revealed a direct interaction between FOXL2 and the activation function (AF)-1/2 domain of ERß. The expression of FOXL2 represses the ligand-dependent transcriptional activation of ERß, but FOXL2 does not influence the ligand-dependent transcriptional activation of ERα. Consistent with these results, RNA interference-mediated depletion of FOXL2 stimulates the expression of the ERß-downstream gene p450 aromatase. The convergence between FOXL2 functions and ERß-mediated transcription in the ovary suggests the putative mechanism of FOXL2 in early-phase follicular development, which may be partially attributed to the regulation of ERß-dependent gene expression.

CCAR2 negatively regulates nuclear receptor LXRα by competing with SIRT1 deacetylase.

Liver X receptors (LXRs) monitor endogenous sterol levels to maintain whole-body cholesterol levels and regulate inflammatory responses. Recent studies have demonstrated that LXRs may inhibit cellular proliferation, but the underlying mechanism remains unclear. Cell cycle and apoptosis regulator 2 (CCAR2), previously known as DBC1/KIAA1967, is a transcriptional regulator that regulates cellular proliferation and energy metabolism by inhibiting sirtuin 1 (SIRT1) deacetylase. Based on the findings that CCAR2 regulates several nuclear receptors, including the estrogen receptors and androgen receptor, we aimed to identify the underlying mechanism of CCAR2 regulation of LXRα. We found that CCAR2 formed a complex with LXRα in a ligand-independent manner in HepG2 cells, and in vitro pull-down assays, it revealed a direct interaction between the amino terminus of CCAR2 and the AF-2 domain of LXRα. Thereby, CCAR2 attenuates the ligand-dependent transcriptional activation function of LXRα. RNA interference-mediated depletion of endogenous CCAR2 potentiated the expression of the LXRα target genes ATP-binding cassette transporter A1 and G1, and the abrogation of CCAR2 resulted in decreased cellular proliferation. Moreover, competitive immunoprecipitation studies revealed that the LXRα downregulation involves the inhibition of SIRT1-LXRα complex formation. Therefore, these results clearly indicate a novel mechanism in which CCAR2 may regulate the transcriptional activation function of LXRα due to its specific inhibition of SIRT1 and serve to regulate cellular proliferation.

SIRT3 positively regulates the expression of folliculogenesis- and luteinization-related genes and progesterone secretion by manipulating oxidative stress in human luteinized granulosa cells.

SIRT3 is a member of the sirtuin family and has recently emerged as a vital molecule in controlling the generation of reactive oxygen species (ROS) in oocytes. Appropriate levels of ROS play pivotal roles in human reproductive medicine. The aim of the present study was to investigate SIRT3 expression and analyze the SIRT3-mediated oxidative response in human luteinized granulosa cells (GCs). Human ovarian tissues were subjected to immunohistochemical analysis to localize SIRT3 expression. Hydrogen peroxide and human chorionic gonadotropin were used to analyze the relationship between ROS and SIRT3 by quantitative RT-PCR and Western blotting. Intracellular levels of ROS were investigated by fluorescence after small interfering RNA-mediated knockdown of SIRT3 in human GCs. To uncover the role of SIRT3 in folliculogenesis and luteinization, mRNA levels of related genes and the progesterone concentration were analyzed by quantitative RT-PCR and immunoassays, respectively. We detected the expression of SIRT3 in the GCs of the human ovary. The mRNA levels of SIRT3, catalase, and superoxide dismutase 1 were up-regulated by hydrogen peroxide in both COV434 cells and human GCs and down-regulated by human chorionic gonadotropin. Knockdown of SIRT3 markedly elevated ROS generation in human GCs. In addition, SIRT3 depletion resulted in decreased mRNA expression of aromatase, 17ß-hydroxysteroid dehydrogenase 1, steroidogenic acute regulatory protein, cholesterol side-chain cleavage enzyme, and 3ß-hydroxysteroid dehydrogenase in GCs and thus resulted in decreased progesterone secretion. These results have the important clinical implication that SIRT3 might play a positive role in the folliculogenesis and luteinization processes in GCs, possibly by sensing and regulating the generation of ROS. Activation of SIRT3 function might help to sustain human reproduction by maintaining GCs as well as oocytes.

Laparoendoscopic single-site concomitant surgery for gallstones and a giant ovarian teratoma.

Laparoendoscopic single-site (LESS) technique has gained popularity in several fields of surgery. Our patient had multiple gallstones and a left ovarian mature cystic teratoma 12 cm in diameter. She underwent concomitant laparoscopic cholecystectomy and adnectomy using LESS technique. Using a transient gasless technique resulted in the extraction of a giant ovarian tumor through the umbilical incision with no leakage into the abdominal cavity. Concomitant LESS surgery is feasible and has many benefits both for patients and doctors - cosmetics, possibly less pain, avoidance of multiple surgeries and cost-effectiveness. LESS technique is also useful for extracting a giant tumor with the transient gasless technique. This novel method might be applied to the removal of a tumor suspicious for malignancy.

Vaginal evisceration 3 years after abdominal hysterectomy and bilateral salpingo-oophorectomy.

Vaginal evisceration after a pelvic operation is a rare gynecological emergency. When intercourse is the cause, most cases occur within 1 year of surgery. A 53-year-old woman presented to the emergency room for vaginal evisceration half a day after the first postoperative occurrence of intercourse 3 years after an abdominal hysterectomy and bilateral salpingo-oophorectomy. In an emergency laparotomy, the protruding small bowel was replaced within the abdominal cavity. The avulsed vaginal cuff, which measured 6 cm in length and had atrophic but non-necrotic margins, was sutured. Women who go for long periods without intercourse after a hysterectomy, especially post-menopausal women, should be made aware of unrecognized vaginal atrophy that could, in some cases, lead to rupture and evisceration during the next occurrence of intercourse.