Deranged expression of follistatin and follistatin-like protein in women with ovarian endometriosis

Menstrual fluid endometrial stem/progenitor cell and supernatant protein content: cyclical variation and indicative range

STUDY QUESTION

Does natural variation exist in the endometrial stem/progenitor cell and protein composition of menstrual fluid across menstrual cycles in women?

SUMMARY ANSWER

Limited variation exists in the percentage of some endometrial stem/progenitor cell types and abundance of selected proteins in menstrual fluid within and between a cohort of women.

WHAT IS KNOWN ALREADY

Menstrual fluid is a readily available biofluid that can represent the endometrial environment, containing endometrial stem/progenitor cells and protein factors. It is unknown whether there is natural variation in the cellular and protein content across menstrual cycles of individual women, which has significant implications for the use of menstrual fluid in research and clinical applications.

STUDY DESIGN, SIZE, DURATION

Menstrual fluid was collected from 11 non-pregnant females with regular menstrual cycles. Participants had not used hormonal medications in the previous 3 months. Participants collected menstrual fluid samples from up to five cycles using a silicone menstrual cup worn on Day 2 of menstrual bleeding.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Menstrual fluid samples were centrifuged to separate soluble proteins and cells. Cells were depleted of red blood cells and CD45+ leucocytes. Menstrual fluid-derived endometrial stem/progenitor cells were characterized using multicolour flow cytometry including markers for endometrial stem/progenitor cells N-cadherin (NCAD) and stage-specific embryonic antigen-1 (SSEA-1) (for endometrial epithelial progenitor cells; eEPC), and sushi domain containing-2 (SUSD2) (for endometrial mesenchymal stem cells; eMSC). The clonogenicity of menstrual fluid-derived endometrial cells was assessed using colony forming unit assays. Menstrual fluid supernatant was analyzed using a custom magnetic Luminex assay.

MAIN RESULTS AND THE ROLE OF CHANCE

Endometrial stem/progenitor cells are shed in menstrual fluid and demonstrate clonogenic properties. The intraparticipant agreement for SUSD2+ menstrual fluid-derived eMSC (MF-eMSC), SSEA-1+ and NCAD+SSEA-1+ MF-eEPC, and stromal clonogenicity were moderate-good (intraclass correlation; ICC: 0.75, 0.56, 0.54 and 0.52, respectively), indicating limited variability across menstrual cycles. Endometrial inflammatory and repair proteins were detectable in menstrual fluid supernatant, with five of eight (63%) factors demonstrating moderate intraparticipant agreement (secretory leukocyte protein inhibitor (SLPI), lipocalin-2 (NGAL), lactoferrin, follistatin-like 1 (FSTL1), human epididymis protein-4 (HE4); ICC ranges: 0.57-0.69). Interparticipant variation was limited for healthy participants, with the exception of key outliers of which some had self-reported menstrual pathologies.

LARGE SCALE DATA

N/A. There are no OMICS or other data sets relevant to this study.

LIMITATIONS, REASONS FOR CAUTION

The main limitations to this research relate to the difficulty of obtaining menstrual fluid samples across multiple menstrual cycles in a consistent manner. Several participants could only donate across <3 cycles and the duration of wearing the menstrual cup varied between 4 and 6 h within and between women. Due to the limited sample size used in this study, wider studies involving multiple consecutive menstrual cycles and a larger cohort of women will be required to fully determine the normal range of endometrial stem/progenitor cell and supernatant protein content of menstrual fluid. Possibility for selection bias and true representation of the population of women should also be considered.

WIDER IMPLICATIONS OF THE FINDINGS

Menstrual fluid is a reliable source of endometrial stem/progenitor cells and related endometrial proteins with diagnostic potential. The present study indicates that a single menstrual sample may be sufficient in characterizing a variety of cellular and protein parameters across women's menstrual cycles. The results also demonstrate the potential of menstrual fluid for identifying endometrial and menstrual abnormalities in both research and clinical settings as a non-invasive method for assessing endometrial health.

STUDY FUNDING/COMPETING INTEREST(S)

This study was supported by grants from the Australian National Health and Medical Research Council to C.E.G. (Senior Research Fellowship 1024298 and Investigator Fellowship 1173882) and to J.E. (project grant 1047756), the Monash IVF Research Foundation to C.E.G. and the Victorian Government's Operational Infrastructure Support Program. K.A.W., M.L.D.-T., S.G.S. and J.E. declare no conflicts of interest. C.E.G. reports grants from NHMRC, during the conduct of the study; grants from EndoFound USA, grants from Ferring Research Innovation, grants from United States Department of Defence, grants from Clue-Utopia Research Foundation, outside the submitted work. CEF reports grants from EndoFound USA, grants from Clue-Utopia Research Foundation, outside the submitted work.

The Potential of Non-Invasive Biomarkers for Early Diagnosis of Asymptomatic Patients with Endometriosis

Endometriosis is a disease that affects women of reproductive age and has a significantly negative impact on their well-being. The main symptoms are dysmenorrhoea, chronic pelvic pain and infertility. In many patients the diagnostic process is very long and can take up to 8-12 years. Laparoscopy, an invasive method, is still necessary to confirm the diagnosis. Therefore, development of more effective diagnostic markers appears to be of the utmost importance for early diagnosis of endometriosis and provision of appropriate treatment. From a clinical point of view, detection of early-stage endometriosis in asymptomatic patients is an ideal situation since early diagnosis of endometriosis may delay the onset of symptoms as well as prevent progression and complications. In the meantime, Cancer Antigen 125 (CA-125) is still the most frequently studied and used marker. Other glycoproteins, growth factors and immune markers seem to play an important role. However, the search for an ideal endometriosis marker is still underway. Further studies into the pathogenesis of endometriosis will help to identify biomarkers or sets of biomarkers with the potential to improve and speed up the diagnostic process in a non-invasive way.

Follistatin-like protein 5 inhibits hepatocellular carcinoma progression by inducing caspase-dependent apoptosis and regulating Bcl-2 family proteins

Hepatocellular carcinoma (HCC) is one of the most common and deadly malignant tumors in the world, especially in China. Follistatin‐like protein 5 (FSTL5) is a member of the FSTL family, which is involved in cell proliferation, migration, differentiation, and embryo development. We aimed to investigate the function and underlying mechanism of FSTL5 in HCC. FSTL5 expression was determined by immunohistochemistry staining in a liver cancer tissue microarray (TMA) and the correlation between FSTL5 and the prognosis of HCC patients was analysed. Further proliferation assay, colony formation assay, flow cytometry, and xenograft tumor model were performed to investigate the bioeffects of FSTL5 in HCC in vitro and in vivo. We found that FSTL5 expression was downregulated in HCC tissues and positively correlated with the prognosis of patients with HCC at tumor node metastasis stage I/II. Overexpression of FSTL5 efficiently impaired HCC growth both in vivo and in vitro with an exogenous manner. Mechanistic investigation demonstrated that FSTL5 promoted HCC cell apoptosis in a caspase‐dependent manner and regulated Bcl‐2 family proteins. These results indicate that FSTL5 may be a potential novel target for HCC treatment, and a biomarker for tumor prognosis.

Expression and Role of Peptides, Proteins and Growth Factors in the Pathogenesis of Endometriosis

Growing evidence is demonstrating that several peptides (corticotrophin-releasing factor, urocortins, ghrelin), proteins (leptin, adiponectin) and growth factors (vascular endothelial growth factor; epidermal growth factor family of growth factors and receptors, fibroblast growth factor, insulin like growth factor and insulin like growth factor-binding proteins, transforming growth factor-β and, activin A and related proteins) are expressed in endometriotic implants, and locally play a relevant role in affecting the biological mechanisms leading to endometriosis. They establish a complex network of interactions by which they are therefore able to stimulate angiogenesis, inflammatory cell recruitment and reaction, the growth of endometriotic tissue and its survival through the modulation of the narrow immune system. This review will evaluate the role played by several regulatory peptides, proteins and growth factors in affecting endometrial physiology and the putative mechanisms advocated to explain endometriosis (angiogenesis, cellular and humoral immunity, inflammatory response, endometrial cell proliferation, activation, motility, adhesion and invasion).

Up-Regulation of Follistatin-Like 1 By the Androgen Receptor and Melanoma Antigen-A11 in Prostate Cancer

BACKGROUND

High affinity androgen binding to the androgen receptor (AR) activates genes required for male sex differentiation and promotes the development and progression of prostate cancer. Human AR transcriptional activity involves interactions with coregulatory proteins that include primate-specific melanoma antigen-A11 (MAGE-A11), a coactivator that increases AR transcriptional activity during prostate cancer progression to castration-resistant/recurrent prostate cancer (CRPC).

METHODS

Microarray analysis and quantitative RT-PCR were performed to identify androgen-regulated MAGE-A11-dependent genes in LAPC-4 prostate cancer cells after lentivirus shRNA knockdown of MAGE-A11. Chromatin immunoprecipitation was used to assess androgen-dependent AR recruitment, and immunocytochemistry to localize an androgen-dependent protein in prostate cancer cells and tissue and in the CWR22 human prostate cancer xenograft.

RESULTS

Microarray analysis of androgen-treated LAPC-4 prostate cancer cells indicated follistatin-like 1 (FSTL1) is up-regulated by MAGE-A11. Androgen-dependent up-regulation of FSTL1 was inhibited in LAPC-4 cells by lentivirus shRNA knockdown of AR or MAGE-A11. Chromatin immunoprecipitation demonstrated AR recruitment to intron 10 of the FSTL1 gene that contains a classical consensus androgen response element. Increased levels of FSTL1 protein in LAPC-4 cells correlated with higher levels of MAGE-A11 relative to other prostate cancer cells. FSTL1 mRNA levels increased in CRPC and castration-recurrent CWR22 xenografts in association with predominantly nuclear FSTL1. Increased nuclear localization of FSTL1 in prostate cancer was suggested by predominantly cytoplasmic FSTL1 in benign prostate epithelial cells and predominantly nuclear FSTL1 in epithelial cells in CRPC tissue and the castration-recurrent CWR22 xenograft. AR expression studies showed nuclear colocalization of AR and endogenous FSTL1 in response to androgen.

CONCLUSION

AR and MAGE-A11 cooperate in the up-regulation of FSTL1 to promote growth and progression of CRPC. Prostate 77:505-516, 2017. © 2016 Wiley Periodicals, Inc.

Serum markers for the noninvasive diagnosis of endometriosis

Endometriosis is a disease that affects millions of women worldwide and its diagnosis is still challenging. Medical history, symptoms together with imaging data may address the correct diagnosis, but the gold standard remains laparoscopic assessment with histological confirmation. The development of serum markers as diagnostic tools for endometriosis may allow a prompt and noninvasive diagnosis. Several serum biomarkers have been investigated over the years, but none of these have shown a clinical utility and nowadays the more realistic diagnostic biomarker consists in a panel of biomarkers. The recent introduction of new technologies such as genomics and proteomics may represent the future perspective of endometriosis diagnosis.

Clinical significance of serum follistatin levels in the diagnosis of ovarian endometrioma and benign ovarian cysts

OBJECTIVE

To determine the clinical significance of serum follistatin levels in women with an ovarian endometrioma.

MATERIALS AND METHODS

This is a prospective study of 89 women, 56 with an ovarian endometrioma (endometrioma group) and 33 with a benign ovarian cyst (control group) who underwent laparoscopic excision. Age, parity, body mass index, serum CA-125, serum CA 19-9, and serum follistatin levels were determined for all participants and evaluated as potential prognostic factors prior to laparoscopic cystectomy.

RESULTS

There were no significant differences in demographic factors between the endometrioma group and the control group. However, serum follistatin levels were significantly higher in the endometrioma group (9350 ± 895 pg/mL vs. control group 725 ± 72 pg/mL, p < 0.05). The optimal diagnostic cut-off values (sensitivity and specificity) of CA-125, CA 19-9, and follistatin for ovarian endometrioma were 23.2 IU/mL (82.14% and 72.73%), 30.14 IU/mL (45.28% and 87.50%), and 2350 pg/mL (53.7% and 60.61%), respectively.

CONCLUSION

Despite the increased serum follistatin levels in patients with ovarian endometrioma, CA-125 was determined to be a more sensitive and specific marker than follistatin for the diagnosis of ovarian endometrioma and endometriosis.

The role of TGFβ superfamily members in the pathophysiology of endometriosis

The transforming growth factor-beta (TGFβ) superfamily comprises over 30 dimeric proteins with conserved structures, which play important roles in the control of cellular proliferation, differentiation and apoptosis. These proteins are expressed and finely regulated in human endometrium during the menstrual cycle, which is consistent with their effects on endometrial cell proliferation and tissue remodeling. This review is focused on summarizing the role of key members of the TGFβ superfamily in the pathophysiology of endometriosis. Evidence suggests that TGFβ, activins, inhibins, nodal, bone morphogenetic proteins, growth differentiation factors, and anti-Müllerian hormone are produced by endometriotic lesions and could be involved in the establishment and progression of the disease. Their receptors and signaling pathways may also be altered in the presence of endometriosis and may be potential targets to the development of therapeutic agents.

Towards an understanding of the molecular mechanism of endometriosis: unbalancing epithelial-stromal genetic conflict

OBJECTIVES

Despite the high incidence of endometriosis, the etiology is poorly understood. Much work has been carried out to elucidate the genetic basis of endometriosis owing to the advent of genomic analysis and new network-based analysis methods.

METHODS

This article reviews the English literature for (epi)genome-wide profiling and association studies on the pathogenesis and pathophysiology of endometriosis.

RESULTS

The characteristic 82 up- and 45 down-regulated unique genes in endometriosis included genes encoding cell cycle, growth factors, signal transduction, transcription factors, hormones, cytokines, chemokines and (pro)inflammation, proteases, cell adhesion and motility, stress response and detoxification, immune response, metabolism and others. There appear to be at least two types of genes: some genes (n = 50) may evolve mainly for the benefit of the endometrial growth, and the other genes (n = 55) evolve as a protective mechanism for the endometrial decidualization. The present review has shed new light on the overlapping genetic signatures between endometriosis development and decidualization process.

CONCLUSION

In conclusion, insufficient decidualization due to unbalancing epithelial-stromal genetic conflict may result in future endometriosis.

Follistatin is induced by IL-1β and TNF-α in stromal cells from endometrioma

The aim of this study is to examine the regulation of follistatin, an activin-binding protein, in endometriosis. Endometrioma stromal cells (EoSCs) were obtained from 9 patients undergoing laparoscopy of the ovarian endometrioma. In cultured EoSCs, interleukin 1β (IL-1β) and tumor necrosis factor-α (TNF-α), which could induce activin-A, also induced follistatin messenger RNA (mRNA) and protein. The cystic fluid of endometrioma from 8 patients was obtained to measure the concentration of activin-A and follistatin by enzyme-linked immunosorbent assay (ELISA). Also, activin activity in the fluid was examined by erythroid differentiation assay using mouse erythroleukemia F5-5.fl cells. In the cystic fluid of endometrioma, the mean values of activin-A and follistatin concentration were 36.8 ng/mL and 4.0 ng/mL, respectively. In a bioassay, all 8 samples exhibited activin activity, which was equivalent to recombinant activin-A activity of 12.8 ± 1.4 ng/mL. Although follistatin was present in the cystic fluid of endometrioma, the activity of activin, which is an exacerbation factor of endometriosis, was predominant in vivo.

Diagnostic value of serum activin A and follistatin levels in women with peritoneal, ovarian and deep infiltrating endometriosis

BACKGROUND

Activin A is a growth factor, produced by the endometrium, whose actions are modulated by the binding protein follistatin. Both proteins are detectable in the peripheral serum and their concentrations may be increased in women with endometriosis. The present study was designed to evaluate whether serum levels of activin A and follistatin are altered, and therefore have a potential diagnostic value, in women with peritoneal, ovarian and deep infiltrating endometriosis.

METHODS

We performed a multicenter controlled study evaluating simultaneously serum activin A and follistatin concentrations in women with and without endometriosis. Women with endometriosis (n = 139) were subdivided into three groups: peritoneal endometriosis (n = 28); ovarian endometrioma (n = 61) and deep infiltrating endometriosis (n = 50). The control group (n = 75) consisted of healthy women with regular menstrual cycles. Blood samples were collected from a peripheral vein and assayed for activin A and follistatin using commercially available enzyme immunoassay kits.

RESULTS

The ovarian endometrioma group had serum activin A levels significantly higher than healthy controls (0.22 ± 0.01 ng/ml versus 0.17 ± 0.01 ng/ml, P < 0.01). None of the endometriosis groups had serum follistatin levels which were significantly altered compared with healthy controls; however, levels found in the endometrioma group (2.34 ± 0.32 ng/ml) were higher than that in the deep endometriosis group (1.50 ± 0.17 ng/ml, P < 0.05). The area under the receiver operating characteristic curve of activin A was 0.700 (95% confidence interval: 0.605-0.794), while that of follistatin was 0.620 (95% confidence interval: 0.510-0.730) for the diagnosis of ovarian endometrioma. The combination of both markers into a duo marker index did not improve significantly their diagnostic accuracy.

CONCLUSIONS

The present study demonstrated that serum activin A and follistatin are not significantly altered in peritoneal or deep infiltrating endometriosis and have limited diagnostic accuracy in the diagnosis of ovarian endometrioma.

Activins and related proteins in the establishment of pregnancy

Activin A and related proteins (inhibins, follistatin [FS], follistatin-related gene [FLRG], endometrial bleeding associated factors [ebaf]) are involved in the complex mechanisms allowing the establishment and the maintenance of pregnancy. As a consequence of ovarian progesterone stimuli, activin A is expressed and secreted by the stromal endometrial cells, which locally induces the decidualization process, a prerequisite for implantation. Moreover, activin A does influence the implantation phase, also enhancing cytotrophoblast differentiation, indirectly, by increasing the expression of other molecules involved in embryo implantation, such as matrix metalloproteinases (MMPs) and leukemia inhibitory factor (LIF). The local derangement of activin A pathway in some pregnancy disorders (incomplete and complete miscarriages, recurrent abortion, and ectopic pregnancy [EP]) further sustains the hypothesis that activin A and its related proteins play a relevant role in the establishment of pregnancy.

Differential expression of follistatin and FLRG in human breast proliferative disorders

Background

Activins are growth factors acting on cell growth and differentiation. Activins are expressed in high grade breast tumors and they display an antiproliferative effect inducing G0/G1 cell cycle arrest in breast cancer cell lines. Follistatin and follistatin- related gene (FLRG) bind and neutralize activins. In order to establish if these activin binding proteins are involved in breast tumor progression, the present study evaluated follistatin and FLRG pattern of mRNA and protein expression in normal human breast tissue and in different breast proliferative diseases.

Methods

Paraffin embedded specimens of normal breast (NB - n = 8); florid hyperplasia without atypia (FH - n = 17); fibroadenoma (FIB - n = 17); ductal carcinoma in situ (DCIS - n = 10) and infiltrating ductal carcinoma (IDC - n = 15) were processed for follistatin and FLRG immunohistochemistry and in situ hybridization. The area and intensity of chromogen epithelial and stromal staining were analyzed semi-quantitatively.

Results

Follistatin and FLRG were expressed both in normal tissue and in all the breast diseases investigated. Follistatin staining was detected in the epithelial cytoplasm and nucleus in normal, benign and malignant breast tissue, with a stronger staining intensity in the peri-alveolar stromal cells of FIB at both mRNA and protein levels. Conversely, FLRG area and intensity of mRNA and protein staining were higher both in the cytoplasm and in the nucleus of IDC epithelial cells when compared to NB, while no significant changes in the stromal intensity were observed in all the proliferative diseases analyzed.

Conclusion

The present findings suggest a role for follistatin in breast benign disease, particularly in FIB, where its expression was increased in stromal cells. The up regulation of FLRG in IDC suggests a role for this protein in the progression of breast malignancy. As activin displays an anti-proliferative effect in human mammary cells, the present findings indicate that an increased FST and FLRG expression in breast proliferative diseases might counteract the anti-proliferative effects of activin in human breast cancer.

Activin A increases invasiveness of endometrial cells in an in vitro model of human peritoneum

The aim of this study was to investigate whether activin A has an effect on the attachment and/or invasion of endometrial cells in a modeled peritoneum in vitro. Cultured endometrial stromal cells (ESCs) and endometrial epithelial cells (EECs) were treated with activin A (6.25-50 ng/ml) and with activin A (25 ng/ml) with and without inhibin A or follistatin. Fluorescent labeled cells were added to confluent peritoneal mesothelial cells (PMCs) and to a monolayer of confluent PMCs grown in a Matrigel invasion assay. The rate of endometrial cell attachment and invasion through PMCs was assessed. The expression of cell adhesion proteins N- and E-cadherin was evaluated with real-time RT-PCR. Activin A (25 ng/ml) promoted invasion of the endometrial cells through the modeled peritoneum (>2-fold versus control) and this effect was partially reversed by inhibin A and follistatin. Activin A had no effect on the rate of attachment of the endometrial cells to the PMCs or in the rate of proliferation. In addition, activin A induced a decreased mRNA expression of E-cadherin in cultured EECs. In conclusion, activin A increases invasion of EECs and ESCs into modeled peritoneum. In EECs, this effect may be related to down-regulation of E-cadherin expression. Further studies are warranted to evaluate the role of activin-A in the genesis of the endometriotic lesion.