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J J Brosens

Publications and source records attributed to J J Brosens.

At least 19 recordsLinked to original sources
PubMed2006

Death or survival--progesterone-dependent cell fate decisions in the human endometrial stroma.

The human endometrium undergoes cyclical waves of proliferation, differentiation and apoptosis in response to the rise and fall in ovarian oestradiol and progesterone levels. These hormonal responses in endometrial cells must be tightly kept in check to safeguard tissue homeostasis throughout reproductive life. The discovery that differentiating endometrium highly expresses the tumour suppressor p53, the forkhead transcription factor FOXO1, and promyelocytic leukaemia zinc finger protein (PLZF) has provided new insights into the molecular basis of life and death decisions in response to sex steroid hormones.

Animals↗
PubMed2005

Progesterone pre-treatment potentiates EGF pathway signaling in the breast cancer cell line ZR-75.

Progesterone in hormone replacement therapy (HRT) preparations increases, while hysterectomy greatly reduces, the incidence of breast cancer. Cross-talk between the progesterone and growth factor signaling pathways occurs at multiple levels and this maybe a key factor in breast cancer survival and progression. To test this hypothesis, we characterized the effect of progesterone pre-treatment on the sensitization of the epidermal growth factor (EGF) signaling pathway to EGF in the breast cancer cell line ZR-75. For the first time in ZR-75 cells and in agreement with previous work using synthetic progestins, we demonstrate that pre-treatment with the natural ligand progesterone increases EGF receptor (EGFR) levels and subsequent ligand-dependent phosphorylation. Downstream we demonstrate that progesterone alone increases erk-1 + 2 phosphorylation, potentiates EGF-phosphorylated erk-1 + 2 and maintains these levels elevated for 24 h; over 20 h longer than in vehicle treated cells. Additionally, progesterone increased the levels of STAT5, another component of the EGF signaling cascade. Progesterone increased EGF mediated transcription of a c-fos promoter reporter and the nuclear localization of the native c-fos protein. Furthermore, progesterone and EGF both alone and in combination, significantly increase cell proliferation. Several results presented herein demonstrate the conformity between the action of the natural ligand progesterone with that of synthetic progestins such as MPA and R5020 and allows the postulation that the progestin/progesterone-dependent increase of EGF signaling provides a survival advantage to burgeoning cancer cells and may contribute to the breast cancer risk associated with endogenous progesterone and with progestin-containing HRT.

Breast Neoplasms↗
PubMed2005

Regulated expression of putative membrane progestin receptor homologues in human endometrium and gestational tissues.

Rapid non-genomic actions of progesterone are implicated in many aspects of female reproduction. Recently, three human homologues of the fish membrane progestin receptor (mPR) have been identified. We combined bioinformatic analysis with expression profiling to define further the role of these mPRs in human reproductive tissues. Sequence analysis confirmed that the mPRs belong to a larger, highly conserved family of proteins, termed 'progestin and adiponectin receptors' (PAQRs). A comparison of the expression of mPR transcripts with that of two related PAQR family members, PAQRIII and PAQRIX, in cycling endometrium and pregnancy tissues revealed markedly divergent expression levels and profiles. For instance, endometrial expression of mPRalpha and gamma and PAQRIX was cycle-dependent whereas the onset of parturition was associated with a marked reduction in myometrial mPRalpha and beta transcripts. Interestingly, mPRalpha and PAQRIX were most highly expressed in the placenta, and the tissue expression levels of both genes correlated inversely with that of the nuclear PR. Phylogenetic analysis demonstrated that PAQRIX belongs to the mPR subgroup of proteins. We also validated a polyclonal antibody raised against the carboxy-terminus of human mPRalpha. Immunohistochemical analysis demonstrated more intense immunoreactivity in placental syncytiotrophoblasts than in endometrial glands or stroma. The data suggest important functional roles for mPRalpha, and possibly PAQRIX, in specific reproductive tissues, particularly those that express low levels of nuclear PR.

Adult↗
PubMed2002

Regulated expression of signal transducer and activator of transcription, Stat5, and its enhancement of PRL expression in human endometrial stromal cells in vitro.

Differentiation of human endometrium during the secretory phase of the menstrual cycle is characterized by expression of a variety of genes implicated in the establishment and maintenance of pregnancy. An increased abundance of signal transducers and activators of transcription (Stats) in the secretory phase suggests Stat5 as a component of the differentiation of endometrium in response to ovarian hormone stimulation in vivo. Decidualization is initiated in a subset of endometrial stromal cells (ESC) in vivo during the secretory phase, but it is unclear whether regulated expression of Stat5 is a feature of these cells. Here, therefore, the abundance and subcellular distribution of Stat5 in ESC after a decidualization stimulus of cAMP plus medroxyprogesterone acetate (MPA) has been investigated in vitro. Western blotting revealed an increase in the apparent abundance of Stat5a and Stat5b, in the cytosolic and nuclear fractions, at 2, 3, and 4 d after stimulation. The potential functional relevance of this increase in Stat5 is suggested by the ability of transiently transfected Stat5a or Stat5b to significantly enhance the response of the decidual PRL promoter to cAMP/MPA and attenuation of the response to cAMP/MPA by dominant negative Stat5. Recent evidence suggests endometrial differentiation, including PRL production, as a possible target of antiphospholipid antibodies (aPL) prevalent in recurrent miscarriage. Monoclonal antibody, ID2, which has similar reactivity as human aPL, significantly decreased the apparent abundance of nuclear Stat5b in response to cAMP/MPA and was associated with decreased decidual PRL promoter activation and PRL secretion. Regulated expression of Stat5 is therefore a component of decidual differentiation of human ESC and contributes significantly to activation of the decidual PRL promoter. Alteration of this process by an aPL component suggests decidual differentiation as a potential clinical target in recurrent early miscarriages.

Antibodies, Antiphospholipid↗
PubMed2001

Epididymal epithelium immortalized by simian virus 40 large T antigen: a model to study epididymal gene expression.

Primary cultures of the differentiated, adult epididymal duct epithelium were immortalized by retroviral transduction with the simian virus (SV)40 large T antigen. The canine epididymis was chosen here as a model with high human relevance, representing a convenient and acceptable source of differentiated epididymal tissue and, compared to other animal models, expressing a relatively large number of gene products which are also expressed by the human epididymis. To determine whether the immortalized canine epididymal (IMCE) cells retained a phenotype comparable to the original tissue, epithelial cytokeratins, various epididymal transcription factors as well as mRNAs encoding abundant epididymal secretory proteins, were studied as molecular markers. All IMCE populations obtained after transduction were of epithelial origin. The nuclear androgen receptor (AR) and the polyoma enhancer activator (PEA3), as well as the epididymal mRNA encoding the canine counterparts of human HE1, HE4 and HE5/CD52 epididymal mRNA, were retained in all populations tested. The majority of tested clones were oestrogen receptor ERalpha-positive, but ERbeta-negative, while one ERalpha-negative cell population was positive for ERbeta. The IMCE populations described thus represent useful permanent tools for studying gene expression of the epididymal duct epithelium, and for other types of experiments, examples including drug effects and toxicity on the epididymis.

Animals↗
PubMed2001

Interferon-gamma modulates prolactin and tissue factor expression in differentiating human endometrial stromal cells.

Cytokines such as interferon-gamma (IFNgamma) released by resident uterine immune cells are thought to influence the expression of differentiated function in the human endometrium. Decidualization of the stromal cell compartment is confined to the superficial endometrial layer in the nonpregnant uterus. To explore the molecular mechanism underlying the spatial expression of the decidual phenotype, the effect of IFNgamma on the induction of two well characterized markers of endometrial stromal (ES) cell differentiation, PRL and tissue factor (TF), has been investigated. IFNgamma antagonizes cAMP-mediated PRL protein and messenger RNA expression in primary ES cell cultures through inhibition of decidual PRL promoter activity. In parallel, IFNgamma stimulates Stat-1 (signal transducer and activator of transcription-1) expression, phosphorylation, and translocation to the nucleus. Exogenously expressed Stat-1 potently represses decidual PRL promoter activation, indicating the potential for the inhibitory effects of IFNgamma to be mediated by Stat-1. We demonstrate that although the coactivator CREB-binding protein/p300 is essential for decidual PRL transcription, this coactivator does not appear to be the target for IFNgamma-mediated repression. By contrast, IFNgamma has little effect on cAMP-mediated TF expression, but induces TF in ES cells not exposed to a decidualizing stimulus. This suggested that in vivo TF expression may not be restricted to decidualizing cells of the superficial layer and was confirmed by immunohistochemical analysis demonstrating intense TF staining in the basal stromal compartment during the regeneration phase of the cycle. The differential sensitivity of decidualization-associated genes to IFNgamma illustrates its potential role as a selective biological response modifier that influences regional function within the endometrium.

Cell Differentiation↗
PubMed2001

An appraisal of the role of laparoscopy: past, present, and future.

OBJECTIVE: To review the role of laparoscopy in the management of chronic pelvic pain (CPP). METHOD: A literature search was conducted to obtain a clear perspective on the role of laparoscopy for CPP. RESULTS: Laparoscopy has been widely used as a diagnostic tool in CPP, but often falls short in defining the type and activity of ectopic endometrial-like tissue. Because pelvic endometriosis includes a wide range of lesions, histological confirmation varies greatly. The evaluation of peritoneal endometriosis at laparoscopy can be misleading. In one study 43% of the patients with minimal or mild endometriosis were found at second-look laparoscopy to be free of lesions. Finally, laparoscopy is not without major complications and the risk of undiagnosed bowel injury is likely to be underestimated. CONCLUSION: The diagnosis of endometriosis can no longer be limited to the visual inspection of the pelvis but requires a wider range of investigations to assess the reproductive system and the role of endometriotic lesions and adhesions in CPP.

Chronic Disease↗
PubMed2000

Endometriosis.

Explore the source record for details and available documents.

Animals↗
PubMed1999

Progesterone receptor regulates decidual prolactin expression in differentiating human endometrial stromal cells.

Human endometrial stromal (ES) cells in culture express PRL, a marker of decidualization, in response to sustained activation of protein kinase A (PKA). Cotreatment with the progestin medroxyprogesterone acetate (MPA) enhanced decidual PRL gene activation in the presence of elevated intracellular cAMP levels. This synergy became apparent, at protein and promoter level, after a lag period of 2 days and increased in a time-dependent manner thereafter. Pretreatment with cAMP advanced the time at which synergy between cAMP and MPA was apparent, suggesting that PKA activation sensitized ES cells to the effects of progestins. Analysis of the progesterone receptor (PR) indicated that PR-A was the predominant form in differentiating ES cells, but its abundance decreased markedly during the course of the decidualization response. The decline in PR levels was of functional relevance, as expression of PR-B or PR-A, by transient transfection, dramatically inhibited the activity of a decidual PRL promoter-reporter construct in response to cAMP. Furthermore, the expression of endogenous PRL protein in response to cAMP or cAMP plus MPA was substantially decreased by constitutive expression of green fluorescence protein-tagged PR, which was localized in the nucleus even in the absence of added ligand. Ligand-independent PR inhibition of the decidual PRL promoter was receptor specific, independent of known PR phosphorylation sites, and required minimally a functional DNA-binding domain. Transient expression of steroid receptor coactivator-1e (SRC-1e), but not SRC-1a, allowed synergy between cAMP and MPA without the requirement of sensitization by pretreatment with cAMP. This raised the possibility that SRC-1e was a component of cAMP-dependent sensitization of ES cells, but there was no evidence of altered messenger RNA expression of either SRC-1 isoform during decidualization. In conclusion, cellular PR levels determine the onset of the decidualization response. Initiation of this process requires elevated intracellular cAMP levels that sensitize ES cells to the actions of progestins through down-regulation of cellular PR levels and possibly via modulation of function of an intermediate factor(s) such as SRC-1e.

Cell Differentiation↗
PubMed1996

Human endometrial fibroblasts immortalized by simian virus 40 large T antigen differentiate in response to a decidualization stimulus.

Human endometrial fibroblasts have been immortalized by infection with simian virus 40 large T antigen and established as a permanent cell line, St-2. Biochemical differentiation of this cell line has been demonstrated by the ability of a decidualizing stimulus, 8-bromo-cAMP plus medroxyprogesterone acetate (MPA), to induce PRL secretion and increase the enzymatic activity of estrone sulfatase. MPA, alone or in combination with estradiol, was unable to elicit this response, but potentiated the effect of 8-bromo-cAMP on PRL production and estrone sulfatase activity. The increase in PRL protein was accompanied by an increase in PRL messenger RNA and increased expression of the insulin-like growth factor-binding protein-1 messenger RNA. The St-2 cell PRL transcript was larger than the pituitary PRL transcript, suggesting its initiation from the distal, nonpituitary, PRL promoter. This was confirmed by reverse transcription-PCR analysis of PRL transcripts using primers specific for the additional sequences present only in the 5'-untranslated region of RNA initiated from the distal promoter. Transient transfection of a reporter construct containing 3000 bp of DNA 5' to the decidual-specific promoter of the human PRL gene demonstrated that cAMP was capable of activating this distal promoter in St-2 cells. In conclusion, this novel cell line provides an interesting new model in which to pursue aspects of biochemical differentiation of human endometrium in vitro.

8-Bromo Cyclic Adenosine Monophosphate↗
PubMed1995

Uterine junctional zone: function and disease.

The myometrium is usually thought of as a homogeneous mass of smooth muscle fibres. However, magnetic resonance studies of the uterus have revealed two distinct zones--the subendometrial myometrium or junctional zone and the outer myometrium. The junctional zone is not only structurally but also functionally different from the outer myometrium. For instance, myometrial contractions in a non-pregnant woman originate exclusively from the junctional zone, and their amplitude, frequency, and direction depend on the phase of the cycle. Irregular thickening of the junctional zone has been proposed as the magnetic resonance criterion for the diagnosis of diffuse adenomyosis. However, this magnetic resonance appearance relies on the disruption of the inner myometrial architecture secondary to smooth muscle hyperplasia but does not provide proof of mucosal invasion of the myometrium. We postulate that adenomyosis is a dichotomous disease characterised primarily by disruption of the inner myometrial architecture and function, with secondary infiltration of endometrial elements into the myometrium under certain circumstances. This hypothesis focuses on the inner myometrium and may explain the high incidence of superficial adenomyosis in dysfunctional uterine bleeding.

Endometriosis↗
PubMed1995

The potential value of magnetic resonance imaging in infertility.

The potential value of magnetic resonance imaging as a diagnostic tool in infertility was investigated. Twenty-six women with primary or secondary infertility and symptoms of dysmenorrhoea or menorrhagia were studied prospectively using conventional T1- and T2-weighted spin-echo techniques. Positive diagnoses were obtained in 20 of 26 (76.9%) patients. Of these, 18 (69.2%) had lesions likely to be significantly contributing to infertility. Adenomyosis was detected in 14 patients (53.8%) with 11 showing the diffuse pattern while three had discrete adenomyomas. Cystic lesions typical of endometriosis were detected in seven patients (26.9%), four of these also had evidence of adenomyosis. The endometriotic lesions were also seen at laparoscopy in each case. Five patients (19.2%) had leiomyomas, one in a patient with adenomyosis and endometriosis and one in a patient with endometriosis alone. Only one patient had submucous leiomyomas causing significant distortion of the endometrial mucosa likely to affect fertility. Magnetic resonance imaging is valuable in the investigation of unexplained infertility where it provides a high diagnostic yield particularly if uterine pathology is suspected.

Adult↗
PubMed1995

Endovaginal ultrasonography in the diagnosis of adenomyosis uteri: identifying the predictive characteristics.

OBJECTIVE: To evaluate prospectively the role of endovaginal ultrasonography in the diagnosis of adenomyosis and to identify predictive characteristics. SETTING: In Vitro Fertilisation Unit, Hammersmith Hospital. SUBJECTS: Fifty-six women with menorrhagia and dysmenorrhea. DESIGN: Endovaginal sonography was performed and uterine body morphometry and myometrial echogenicity were assessed. The sonographic suspicion of adenomyosis was scored high or low depending on the degree of uterine enlargement, uterine asymmetry not due to fibroids and heterogenicity of myometrial echoes. The sonographic diagnosis was compared either with the histological findings after hysterectomy (n = 34) or to the appearances on magnetic resonance imaging (n = 22). RESULTS: Adenomyosis was diagnosed in 28 patients: 15 by histology and 13 by magnetic resonance imaging. Endovaginal ultrasound demonstrated a sensitivity of 86%, a specificity of 50%, a positive predictive value of 86%, and a negative predictive value of 77%. Uterine morphometry alone did not predict adenomyosis: although the mean length of the longitudinal, anteroposterior and transverse axis was larger in uteri with, compared with those without, adenomyosis, this did not reach statistical significance. The uterine asymmetry ratio was 1.43 (SD 0.6) and 1.34 (SD 0.4) (P = 0.26) in uteri with and without adenomyosis, respectively, but in the presence of adenomyosis the mean posterior wall was significantly thicker than the mean anterior wall: 25.6 (SD 6.6) mm compared with 21.8 (SD 5.0) mm, P = 0.02. Therefore, adenomyosis was best predicted on the basis of ill-defined myometrial heterogeneity. However, leiomyomas and various echogenic shadows and artefacts often complicate subjective assessment of the myometrial echogenicity. CONCLUSION: Endovaginal sonography in symptomatic patients can be a sensitive but not a specific procedure for the diagnosis of adenomyosis.

Adult↗
PubMed1995

The role of myometrial needle biopsies in the diagnosis of adenomyosis.

OBJECTIVE: To determine the sensitivity and specificity of myometrial needle biopsies in the diagnosis of adenomyosis uteri in vitro. DESIGN: Eight needle biopsies and 8 corresponding myometrial blocks were taken from 27 hysterectomy specimens with adenomyosis and 13 specimens with adenomyosis. Adenomyosis was graded on the basis of the depth of endometrial invasion into the myometrium: grade I, adenomyosis within the inner third of the myometrium; grade II, limited to the inner two thirds; and grade III, endometrial penetration into the outer one third of the myometrium. The sensitivity of 4 and 2 biopsies was calculated by conventional probability theory. RESULTS: Taking 8 needle biopsies from each uterus yielded sensitivities for grade I, II, and III adenomyosis of 9%, 64%, and 100% respectively, but the calculated sensitivities of two biopsies, taken at random, were only 2.3%, 20%, and 56%, respectively. There were no false-positive biopsies. CONCLUSIONS: Myometrial needle biopsy is a highly specific technique for the diagnosis of adenomyosis uteri but the sensitivity is low and dependent on the number of biopsies and the depth of adenomyosis.

Biopsy, Needle↗