matrix metalloproteinases (MMPs) are postulated to facilitate follicular rupture. In the present study, expression of the stromelysins (MMP3, MMP10, MMP11) was analyzed in the periovulatory human and rat ovary. Human granulosa and theca cells were collected from the dominant follicle at various times after human chorionic gonadotropin (hCG). Intact rat ovaries, granulosa cells, and residual tissue (tissue remaining after granulosa cell collection) were isolated from equine CG (eCG)-hCG-primed animals. Mmp10 mRNA was highly induced in human granulosa and theca cells and intact rat ovaries, granulosa cells, and residual tissue. Localization of MMP10 to granulosa and theca cells in both human and rat ovarian follicles was confirmed by immunohistochemistry. Mmp3 mRNA was unchanged in human cells and rat granulosa cells, but increased in intact rat ovaries and residual tissue. Mmp11 mRNA decreased following hCG treatment in human granulosa and theca cells as well as rat granulosa cells. Regulation of Mmp10 in cultured rat granulosa cells revealed that the EGF inhibitor AG1478 and the progesterone receptor antagonist RU486 suppressed the induction of Mmp10 mRNA, whereas the prostaglandin inhibitor NS398 had no effect. Studies on the Mmp10 promoter demonstrated that forskolin plus PMA stimulated promoter activity, which was dependent upon a proximal AP1 site. In conclusion, there are divergent patterns of stromelysin expression associated with ovulation, with a marked induction of Mmp10 mRNA and a decrease in Mmp11 mRNA, yet a species-dependent pattern on Mmp3 mRNA expression. The induction of Mmp10 expression suggests an important role for this MMP in the follicular changes associated with ovulation and subsequent luteinization.
Expression of the metalloproteinase Mmp10 mRNA is stimulated by hCG prior to follicular rupture in both the human and the rat ovary, indicating involvement in ovulation and subsequent luteinization.
extracellular matrix; granulosa cells; matrix metalloproteinase; ovulation; ovulatory cycle; proteinases; theca cells
Working memory is a cognitive function that is affected by aging and disease. To better understand the neural substrates for working memory, the present study examined the influence of estradiol on working memory using functional magnetic resonance imaging. Pre-menopausal women were tested on a verbal n-back task during the early (EF) and late follicular (LF) phases of the menstrual cycle. Although brain activation patterns were similar across the two phases, the most striking pattern that emerged was that estradiol had different associations with the two hemispheres. Increased activation in left frontal circuitry in the LF phase was associated with increased estradiol levels and decrements in working memory performance. In contrast, increased activation in right hemisphere regions in the LF phase was associated with improved task performance. The present study showed that better performance in the LF than the EF phase was associated with a pattern of reduced recruitment of the left-hemisphere and increased recruitment of the right-hemisphere in the LF compared to EF phase. We speculate that estradiol interferes with left-hemisphere working-memory processing in the LF phase, but that recruitment of the right hemisphere can compensate for left-hemisphere interference. This may be related to the proposal that estradiol can reduce cerebral asymmetries by modulating transcallosal communication (Hausmann, 2005).
functional magnetic resonance imaging; n-back; menstrual cycle; performance; hemispheric lateralization
The matrix metalloproteinase (MMP) family is believed to play a role in the ovulatory process because MMP inhibitors block oocyte release. However, little is known about the mechanisms by which the MMPs affect ovulation. The present study investigated the degradomic actions of the gelatinases, MMP2 and MMP9, by identifying gelatinolytic targets in periovulatory granulosa cells. Granulosa cells were collected from immature rats 48 h after equine chorionic gonadotropin treatment and were cultured with human chorionic gonadotropin (hCG) in the absence or presence of a specific MMP2/9 inhibitor ((2R)-2-[(4-biphenylylsulfonyl)amino]-3-phenylpropionic acid) for an additional 24 h. The conditioned media was analyzed for gelatinolytic activity, progesterone, and peptide profiles. Gelatinolytic activity and progesterone were induced in response to hCG; however, there was no difference in progesterone between cells treated with or without the inhibitor. Peptide fragments of proteins altered in the presence of the gelatinase inhibitor were identified by two-dimensional gel electrophoresis and mass spectrometry. Protein disulfide isomerase A3 (PDIA3), which plays a role in protein folding, was identified as a peptide that decreased in the presence of inhibitor while the serine protease hepsin, was found to increase with inhibitor treatment. Subsequent experiments established that PDIA3 and hepsin were targets of MMP2/9 action by cleavage with MMP2 and Western blot analysis, respectively. Additionally, hepsin was identified as a gelatinolytic target in ovarian cancer cells. In the present study, proteomics has identified proteins that may be involved in novel ways in the complex cascades that are mediated by gelatinolytic MMPs during the periovulatory period.
Gelatinases from rat granulosa cells degrade hepsin and protein disulfide isomerase A3.
corpus luteum; hepsin; matrix metalloproteinase; ovulation; protein disulfide isomerase A3
The highly conserved polo-like kinases (Plks) are potent regulators of multiple functions in the cell cycle before and during mitotic cell division. We investigated the expression pattern of Plk genes and their potential role(s) in the rat ovary during the periovulatory period. Plk2 and Plk3 were highly induced both in intact ovaries and granulosa cells in vivo after treatment with the luteinizing hormone (LH) agonist, human chorionic gonadotropin (hCG). In vitro, hCG stimulated the expression of Plk2 in granulosa cells, but not Plk3. This induction of Plk2 expression was mimicked by both forskolin and phorbol 12 myristate 13-acetate (PMA). Moreover, Plk2 expression was reduced by inhibitors of prostaglandin synthesis or the EGF pathway, but not by progesterone receptor antagonist (RU486) treatment. At the promoter level, mutation of the Sp1 binding sequence abolished the transcriptional activity of the Plk2 gene. ChIP assays also revealed the interaction of endogenous Sp1 protein in the Plk2 promoter region. Functionally, the over-expression of Plk2 and Plk3 arrested granulosa cells at the G0/G1 phase of the cell cycle. In contrast, the knockdown of Plk2 expression in granulosa cells decreased the number of cells in the G0/G1 stage of the cell cycle, but increased granulosa cell viability. In summary, hCG induced Plk2 and Plk3 expression in the rat ovary. Prostaglandins and the EGF signaling pathway are involved in regulating Plk2 expression. The transcription factor Sp1 is important for Plk2 transcriptional up-regulation. Our findings suggest that the increase in Plk2 and Plk3 expression contributes to the cell cycle arrest of granulosa cells which is important for the luteinization of granulosa cells during the periovulatory period.
The process of ovulation involves weakening of the follicular wall by proteolytic enzymes. The function of FURIN (also known as PCSK3) is to activate various proteolytic enzymes. In the present study, the expression, localization, and function of FURIN were investigated in the periovulatory rat ovary. Immature female rats were injected with equine chorionic gonadotropin followed by human chorionic gonadotropin (hCG) 48 h later to stimulate ovulation. Ovaries were collected at 0, 4, 8, 12, and 24 h after hCG injection. Administration of hCG increased Furin mRNA expression in both intact ovaries and cultured ovarian follicles to maximal levels at 8 and 12 h before decreasing at 24 h. In cultured granulosa cells, Furin mRNA levels were significantly induced at 12 h after hCG. In situ hybridization of Furin mRNA demonstrated expression in the granulosa cells, with predominant expression in the theca layer. Regulation studies demonstrated that Furin mRNA was induced in residual tissue by forskolin or amphiregulin. To examine the role of FURIN in protease activation and ovulation, rats were treated with a FURIN inhibitor and oocyte release was determined. There was a 38% decrease in the number of oocytes released in ovaries treated with the FURIN inhibitor. Likewise, the FURIN inhibitor decreased the activation of MMP2. The induction of Furin mRNA after treatment with hCG, along with the decrease in MMP2 activation and oocyte release after FURIN inhibition, supports the hypothesis that FURIN is upregulated during the preovulatory period, which results in activation of proteinases associated with the breakdown of the follicular wall during ovulation.
Furin mRNA is upregulated by hCG prior to ovulation and FURIN inhibition blocks MMP2 activation and oocyte release.
follicle; ovary; ovulation; proteinase; theca cells
Peroxisome Proliferator Activated Receptor gamma (PPARγ) agonists, such as the thiazolinediones (TZDs), have been studied for their potential use as cancer therapeutic agents. We investigated the effect of four TZDs—Rosiglitazone (Rosi), Ciglitazone (CGZ), Troglitazone (TGZ), and Pioglitazone (Pio)—on ovarian cancer cell proliferation, PPARγ expression and PPAR luciferase reporter activity. We explored whether TZDs act in a PPARγ dependent or independent manner by utilizing molecular approaches to inhibit or overexpress PPARγ activity.
Treatment with CGZ or TGZ for 24 hours decreased proliferation in three ovarian cancer cell lines, Ovcar3, CaOv3, and Skov3, whereas Rosi and Pio had no effect. This decrease in Ovcar3 cell proliferation was due to a higher fraction of cells in the G0/G1 stage of the cell cycle. CGZ and TGZ treatment increased apoptosis after 4 hours of treatment but not after 8 or 12 hours. Treatment with TGZ or CGZ increased PPARγ mRNA expression in Ovcar3 cells; however, protein levels were unchanged. Surprisingly, luciferase promoter assays revealed that none of the TZDs increased PPARγ activity. Overexpression of wild type PPARγ increased reporter activity. This was further augmented by TGZ, Rosi, and Pio indicating that these cells have the endogenous capacity to mediate PPARγ transactivation. To determine whether PPARγ mediates the TZD-induced decrease in proliferation, cells were treated with CGZ or TGZ in the absence or presence of a dominant negative (DN) or wild type overexpression PPARγ construct. Neither vector changed the TZD-mediated cell proliferation suggesting this effect of TZDs on ovarian cancer cells may be PPARγ independent.
CGZ and TGZ cause a decrease in ovarian cancer cell proliferation that is PPARγ independent. This concept is supported by the finding that a DN or overexpression of the wild type PPARγ did not affect the changes in cell proliferation and cell cycle.
The LH surge induces specific transcription factors that regulate the expression of a myriad of genes in periovulatory follicles to bring about ovulation and luteinization. The present study determined 1) the localization of RUNX1, a nuclear transcription factor, 2) regulation of Runx1 mRNA expression, and 3) its potential function in rat ovaries. Up-regulation of mRNA and protein for RUNX1 is detected in preovulatory follicles after human chorionic gonadotropin (hCG) injection in gonadotropin-treated immature rats as well as after the LH surge in cycling animals by in situ hybridization and immunohistochemical and Western blot analyses. The regulation of Runx1 mRNA expression was investigated in vitro using granulosa cells from rat pre-ovulatory ovaries. Treatments with hCG, forskolin, or phorbol 12 myristate 13-acetate stimulated Runx1 mRNA expression. The effects of hCG were reduced by inhibitors of protein kinase A, MAPK kinase, or p38 kinase, indicating that Runx1 expression is regulated by the LH-initiated activation of these signaling mediators. In addition, hCG-induced Runx1 mRNA expression was inhibited by a progesterone receptor antagonist and an epidermal growth factor receptor tyrosine kinase inhibitor, whereas amphiregulin stimulated Runx1 mRNA expression, demonstrating that the expression is mediated by the activation of the progesterone receptor and epidermal growth factor receptor. Finally, knockdown of Runx1 mRNA by small interfering RNA decreased progesterone secretion and reduced levels of mRNA for Cyp11a1, Hapln1, Mt1a, and Rgc32. The hormonally regulated expression of Runx1 in periovulatory follicles, its involvement in progesterone production, and regulation of preovulatory gene expression suggest important roles of RUNX1 in the periovulatory process.
AML1, Acute myeloid leukemia 1; AREG, amphiregulin; cdkn, cyclin-dependent kinase inhibitor; C/EBPβ, CCAAT-enhancer binding protein β; CG, chorionic gonadotropin; DMSO, dimethylsulfoxide; EGF, epidermal growth factor; Hapln1, hyaluronan and proteoglycan link protein 1; MEK, MAPK kinase; Mt1a, metallothionein 1a; PGR, progesterone receptor; PKA, protein kinase A; PKC, protein kinase C; PMA, phorbol 12 myristate 13-acetate; PMSG, pregnant mare serum gonadotropin; Rgc32, response gene to complement 32; siRNA, small interfering RNA; Timp1, tissue inhibitor of metalloproteinase-1
Objective: This prospective study was undertaken to examine the effects of subclinical intraamniotic
infection on fetal behavioral patterns.
Methods: Amniotic fluid was obtained from four groups of patients (n = 99): group 1, patients
with preterm premature rupture of the fetal membranes (PPROM) without infection; group 2,
patients with PPROM and infection; group 3, patients with preterm labor (PTL) and without
infection; and group 4, patients with PTL and infection. Fetal biophysical profiles were obtained on
admission to the labor suite. Amniotic fluid was analyzed for the presence of microorganisms and
endotoxin to confirm intraamniotic infection; cytokines interleukin (IL)-1β, IL-6, and IL-8 were
Results: We found no association between low scores for biophysical parameters and subclinical
infection in patients with PPROM or PTL.
Conclusions: We could not demonstrate that upon a patient's admission to the labor hall absent
fetal breathing and absent fetal movement, as well as reactivity, correlate with subclinical intraamniotic
infection. Elevated cytokines, i.e. IL-1β, IL-6, and IL-8 were associated with subclinical