BMP6 Downregulates GDNF Expression Through SMAD1/5 and ERK1/2 Signaling Pathways in Human Granulosa-Lutein Cells

Thyroid transcriptomic profiling reveals the differential regulation of lncRNA and mRNA related to prolificacy in Small Tail Han sheep with FecB++ genotype

The thyroid gland is an important endocrine gland in animals, which mainly secretes thyroid hormones and acts on various organs of the body. Long-chain non-coding RNA (lncRNA) plays an important role in animal reproduction. However, there is still a lack of understanding of their expression patterns and potential roles in the thyroid of Small Tail Han (STH) sheep. In this study, RNA-seq was used to examine the transcriptome expression patterns of lncRNAs and mRNAs in the follicular phase (ww_FT) and luteal phase (ww_LT) in FecB++ genotype STH Sheep. A total of 17,217 lncRNAs and 39,112 mRNAs were identified including 96 differentially expressed lncRNAs (DELs) and 1054 differentially expressed mRNAs (DEGs). Functional analysis of genes with significant differences in expression level showed that these genes could be enriched in Ras signalling pathway, hedgehog (HH) signalling pathway, ATP-binding cassette (ABC) transporters and other signalling pathways related to animal reproduction. In addition, through correlation analysis for lncRNA-mRNA co-expression and network construction, we found that LNC_009115 and LNC_005796 trans target NIK-related kinase (NRK) and poly(A)-specific ribonuclease (PARN). LNC_007189 and LNC_002045 trans target progesterone-induced blocking factor 1 (PIBF1), LNC_009013 trans targets small mothers against decapentaplegic (SMAD1) are related to animal reproduction. These genes add new resources for elucidating the regulatory mechanisms of reproduction in sheep with different reproductive cycles of the FecB++ genotype STH sheep.

Gene expression associated with unfavorable vaginal bleeding in women using the etonogestrel subdermal contraceptive implant: a prospective study

To evaluate gene expression associated with unfavorable vaginal bleeding in users of the Etonogestrel (ENG) contraceptive implant. Prospective study involving 100 women who intended to use the ENG implant. Exclusion criteria included abnormal uterine bleeding, inability to attend a 1-year follow-up, and implant removal for reasons unrelated to vaginal bleeding or loss of follow-up. We obtained endometrial biopsies before implant placement and assessed the expression of 20 selected genes. Users maintained a uterine bleeding diary for 12 months post-implant placement. For statistical analysis, we categorized women into those with or without favorable vaginal bleeding at 3 and 12 months. Women with lower CXCL1 expression had a 6.8-fold increased risk of unfavorable vaginal bleeding at 3 months (OR 6.8, 95% CI 2.21-20.79, p < 0.001), while those with higher BCL6 and BMP6 expression had 6- and 5.1-fold increased risks, respectively. By the 12-month follow-up, women with lower CXCL1 expression had a 5.37-fold increased risk of unfavorable vaginal bleeding (OR 5.37, 95% CI 1.63-17.73, p = 0.006). Women with CXCL1 expression < 0.0675, BCL6 > 0.65, and BMP6 > 3.4 had a higher likelihood of experiencing unfavorable vaginal bleeding at 3 months, and CXCL1 < 0.158 at 12 months. Users of ENG contraceptive implants with elevated BCL6 and BMP6 expression exhibited a higher risk of breakthrough bleeding at the 3-month follow-up. Conversely, reduced CXCL1 expression was associated with an elevated risk of bleeding at both the 3 and 12-month follow-ups.

Landscape of pathogenic mutations in premature ovarian insufficiency

Premature ovarian insufficiency (POI) is a major cause of female infertility due to early loss of ovarian function. POI is a heterogeneous condition, and its molecular etiology is unclear. To identify genetic variants associated with POI, here we performed whole-exome sequencing in a cohort of 1,030 patients with POI. We detected 195 pathogenic/likely pathogenic variants in 59 known POI-causative genes, accounting for 193 (18.7%) cases. Association analyses comparing the POI cohort with a control cohort of 5,000 individuals without POI identified 20 further POI-associated genes with a significantly higher burden of loss-of-function variants. Functional annotations of these novel 20 genes indicated their involvement in ovarian development and function, including gonadogenesis (LGR4 and PRDM1), meiosis (CPEB1, KASH5, MCMDC2, MEIOSIN, NUP43, RFWD3, SHOC1, SLX4 and STRA8) and folliculogenesis and ovulation (ALOX12, BMP6, H1-8, HMMR, HSD17B1, MST1R, PPM1B, ZAR1 and ZP3). Cumulatively, pathogenic and likely pathogenic variants in known POI-causative and novel POI-associated genes contributed to 242 (23.5%) cases. Further genotype-phenotype correlation analyses indicated that genetic contribution was higher in cases with primary amenorrhea compared to that in cases with secondary amenorrhea. This study expands understanding of the genetic landscape underlying POI and presents insights that have the potential to improve the utility of diagnostic genetic screenings.

BMP6 regulates AMH expression via SMAD1/5/8 in goat ovarian granulosa cells

Anti-Müllerian hormone (AMH) is produced by ovarian granulosa cells (GCs)and plays a major role in inhibiting the recruitment of primordial follicles and reducing the sensitivity of growing follicles to follicle-stimulating hormone (FSH). Bone morphogenetic protein 6 (BMP6) has similar spatiotemporal expression to AMH during follicular development, suggesting that BMP6 may regulate AMH expression. However, the specific mechanism by which BMP6 regulates AMH expression remains unclear. The objectives of this study were to examine the molecular pathway by which BMP6 regulates AMH expression. The results showed that BMP6 promoted the secretion and expression of AMH in goat ovarian GCs. Mechanistically, BMP6 upregulated the expression of sex-determining region Y-box 9 (SOX9) and GATA-binding factor 4 (GATA4), which was associated with the transcriptional initiation of AMH. AMH expression was significantly decreased by GATA4 knockdown. Moreover, BMP6 treatment promoted the phosphorylation of SMAD1/5/8, whereas inhibiting the SMAD1/5/8 signaling pathway significantly abolished BMP6-induced upregulation of AMH and GATA4 expression. Interestingly, the activation of SMAD1/5/8 alone did not affect the expression of AMH or GATA4. The results suggested that BMP6 upregulated GATA4 through the SMAD1/5/8 signaling pathway, which in turn promoted AMH expression.

NORAD promotes multiple myeloma cell progression via BMP6/P-ERK1/2 axis

Multiple myeloma (MM) is one of the most common tumors of the hematological system and remains incurable. Recent studies have shown that long noncoding RNA NORAD is a potential oncogene in a variety of tumors. However, the general biological role and clinical value of NORAD in MM remains unknown. In this study, we measured NORAD expression in bone marrow of 60 newly diagnosed MM, 30 post treatment MM and 17 healthy donors by real-time quantitative polymerase chain reaction (qPCR). The NORAD gene was knockdown by lentiviral transfection in MM cell lines, and the effects of NORAD on apoptosis, cell cycle and cell proliferation in MM cells were examined by flow cytometry, CCK8 assay, EDU assay and Western blot, and the differential genes after knockdown of NORAD were screened by mRNA sequencing, followed by in vivo experiments and immunohistochemical assays. We found that knockdown of NORAD promoted MM cell apoptosis, induced cell cycle G1 phase arrest, and inhibited MM cell apoptosis in in vivo and in vitro experiments. Mechanistically, NORAD plays these roles through the BMP6/P-ERK1/2 axis. We discuss a novel mechanism by which NORAD acts pro-tumorigenically in MM via the BMP6/P-ERK1/2 axis.

The Interleukin-6 trans-signaling promotes progesterone production in human granulosa-lutein cells

As a critical paracrine regulator of multiple reproductive functions, the cytokine interleukin-6 (IL-6) is expressed in human granulosa cells and can be detected in follicular fluid. At present, the functional role of IL-6 in the regulation of ovarian steroidogenesis is controversial. Moreover, the detailed molecular mechanisms by which IL-6 regulates the production of progesterone in human granulosa cells remain to be elucidated. In the present study, we used primary and immortalized human granulosa-lutein (hGL) cells to investigate the effects of IL-6 on progesterone synthesis and the underlying molecular mechanisms. We found that IL-6 trans-signaling by the combined addition of IL-6 and soluble IL-6 receptor (sIL-6Rα) induced StAR expression and progesterone production in hGL cells. Additionally, IL-6/sIL-6Rα activated the phosphorylation of Janus activated kinase 2 (JAK2) and signal transducer and activator of transcription 3 (STAT3), and the cellular effects were abolished by AG490 (JAK2 inhibitor), C188–9 (STAT3 inhibitor), or siRNA-mediated knockdown of STAT3. IL-6 trans-signaling-induced activation of JAK2/STAT3 also upregulated the expression of suppressor of cytokine signaling 3 (SOCS3), which, in turn, negatively regulated the JAK2/STAT3 pathway by suppressing STAT3 activation and its downstream effects. Our findings provide insight into the molecular mechanisms by which IL-6 trans-signaling modulates steroidogenesis in hGL cells.

Targeted whole exome sequencing and Drosophila modelling to unveil the molecular basis of primary ovarian insufficiency

STUDY QUESTION

Can a targeted whole exome sequencing (WES) on a cohort of women showing a primary ovarian insufficiency (POI) phenotype at a young age, combined with a study of copy number variations, identify variants in candidate genes confirming their deleterious effect on ovarian function?

SUMMARY ANSWER

This integrated approach has proved effective in identifying novel candidate genes unveiling mechanisms involved in POI pathogenesis.

WHAT IS KNOWN ALREADY

POI, a condition occurring in 1% of women under 40 years of age, affects women’s fertility leading to a premature loss of ovarian reserve. The genetic causes of POI are highly heterogeneous and several determinants contributing to its prominent oligogenic inheritance pattern still need to be elucidated.

STUDY DESIGN, SIZE, DURATION

WES screening for pathogenic variants of 41 Italian women with non-syndromic primary and early secondary amenorrhoea occurring before age 25 was replicated on another 60 POI patients, including 35 French and 25 American women, to reveal statistically significant shared variants.

PARTICIPANTS/MATERIALS, SETTING, METHODS

The Italian POI patients’ DNA were processed by targeted WES including 542 RefSeq genes expressed or functioning during distinct reproductive or ovarian processes (e.g. DNA repair, meiosis, oocyte maturation, folliculogenesis and menopause). Extremely rare variants were filtered and selected by means of a Fisher Exact test using several publicly available datasets. A case-control Burden test was applied to highlight the most significant genes using two ad-hoc control female cohorts. To support the obtained data, the identified genes were screened on a novel cohort of 60 Caucasian POI patients and the same case-control analysis was carried out. Comparative analysis of the human identified genes was performed on mouse and Drosophila melanogaster by analysing the orthologous genes in their ovarian phenotype, and two of the selected genes were fruit fly modelled to explore their role in fertility.

MAIN RESULTS AND THE ROLE OF CHANCE

The filtering steps applied to search for extremely rare pathogenic variants in the Italian cohort revealed 64 validated single-nucleotide variants/Indels in 59 genes in 30 out of 41 screened women. Burden test analysis highlighted 13 ovarian genes as being the most enriched and significant. To validate these findings, filtering steps and Burden analysis on the second cohort of Caucasian patients yielded 11 significantly enriched genes. Among them, AFP, DMRT3, MOV10, FYN and MYC were significant in both patient cohorts and hence were considered strong candidates for POI. Mouse and Drosophila comparative analysis evaluated a conserved role through the evolution of several candidates, and functional studies using a Drosophila model, when applicable, supported the conserved role of the MOV10 armitage and DMRT3 dmrt93B orthologues in female fertility.

LARGE SCALE DATA

The datasets for the Italian cohort generated during the current study are publicly available at ClinVar database (http://www.ncbi.nlm.nih.gov/clinvar/): accession numbers SCV001364312 to SCV001364375.

LIMITATIONS, REASONS FOR CAUTION

This is a targeted WES analysis hunting variants in candidate genes previously identified by different genomic approaches. For most of the investigated sporadic cases, we could not track the parental inheritance, due to unavailability of the parents’ DNA samples; in addition, we might have overlooked additional rare variants in novel candidate POI genes extracted from the exome data. On the contrary, we might have considered some inherited variants whose clinical significance is uncertain and might not be causative for the patients’ phenotype. Additionally, as regards the Drosophila model, it will be extremely important in the future to have more mutants or RNAi strains available for each candidate gene in order to validate their role in POI pathogenesis.

WIDER IMPLICATIONS OF THE FINDINGS

The genomic, statistical, comparative and functional approaches integrated in our study convincingly support the extremely heterogeneous oligogenic nature of POI, and confirm the maintenance across the evolution of some key genes safeguarding fertility and successful reproduction. Two principal classes of genes were identified: (i) genes primarily involved in meiosis, namely in synaptonemal complex formation, asymmetric division and oocyte maturation and (ii) genes safeguarding cell maintenance (piRNA and DNA repair pathways).

STUDY FUNDING/COMPETING INTEREST(S)

This work was supported by Italian Ministry of Health grants ‘Ricerca Corrente’ (08C621_2016 and 08C924_2019) provided to IRCCS Istituto Auxologico Italiano, and by ‘Piano Sostegno alla Ricerca’ (PSR2020_FINELLI_LINEA_B) provided by the University of Milan; M.P.B. was supported by Telethon-Italy (grant number GG14181). There are no conflicts of interest.

Bone morphogenetic protein 2 upregulates SERPINE2 expression through noncanonical SMAD2/3 and p38 MAPK signaling pathways in human granulosa-lutein cells

Serine protease inhibitor-E2 (SERPINE2) is highly expressed in the granulosa cells of growing follicles and the dynamic changes in SERPINE2 expression are correlated with follicular development and ovulation in several mammals, including mice, cattle, sheep, and humans. Bone morphogenetic proteins (BMPs) and their functional receptors are extensively expressed in the ovary and play critical roles in the regulation of ovarian folliculogenesis and luteal function. To date, whether BMPs regulate the expression of SERPINE2 during human follicular development remains to be elucidated. The aim of this study was to investigate the effects of BMPs on the regulation of SERPINE2 expression (a major regulator of plasminogen activators [PA]) and the underlying mechanisms using primary and immortalized human granulosa-lutein (hGL) cells. Our results demonstrated that these BMPs (BMP2, BMP4, BMP6, BMP7, and BMP15) induced differential upregulation of SERPINE2 expression. In this regard, BMP2 is the major modulator that has the best cellular activity, which further decreased the production of urokinase PA and tissue PA in hGL cells. In addition to canonical SMAD1/5/8 signaling, BMP2 also activates noncanonical SMAD2/3 and p38 mitogen-activated protein kinase (MAPK) signaling. Using two inhibition approaches (kinase receptor inhibitors and siRNA-mediated knockdown), we found that SMAD2/3-SMAD4 and p38 MAPK, but not SMAD1/5/8 signaling, was involved in the BMP2-induced upregulation of SERPINE2 expression via activin receptor-like kinase 3. These findings deepen our understanding of the differential effect of BMPs in regulating follicular function and provide new insights of the molecular mechanisms by which BMP2 regulates the expression of SERPINE2 in human granulosa cells.

miR-765 Acts as a Tumor Promoter and Indicates Poor Prognosis in Non-Small Cell Lung Cancer

PURPOSE

Non-small cell lung cancer (NSCLC) is one of the leading causes of cancer-related death worldwide with poor prognosis. Accumulating evidence indicates that miR-765 is an important regulator in the progression and prognosis of various cancers. In this study, the function in the progression and prognosis of NSCLC was investigated.

PATIENTS AND METHODS

The expression of miR-765 in NSCLC was analyzed by qRT-PCR. The effect of miR-765 on cell proliferation, migration, and invasion of NSCLC was evaluated by CCK8 and Transwell assay. Kaplan-Meier analysis and Cox regression analysis were employed to assess the prognostic value of miR-765.

RESULTS

The results demonstrated the significant upregulation of miR-765 in NSCLC tissues and cell lines relative to normal tissues and cells. High miR-765 expression was significantly correlated with the TNM stage of patients. Patients with high miR-765 expression showed a poorer prognosis than that of patients with low miR-765 expression. Cox analysis indicated that miR-765 could be considered as an independent prognostic factor for NSCLC. Additionally, the upregulation of miR-765 was revealed to promote NSCLC cell proliferation, migration, and invasion by targeting BMP6.

CONCLUSION

The overexpression of miR-765 in NSCLC was associated with TNM stage and poor prognosis of patients. miR-765 served as a tumor promoter of NSCLC by regulating BMP6. These findings provide a potential biomarker and therapeutic target for the prognosis and treatment of NSCLC.

The IL6/sIL-6Rα trans-signaling increases PGE2 production in human granulosa cells

As a potent autocrine regulator, the proinflammatory cytokine interleukin 6 (IL6) is expressed in granulosa cells and follicular fluid and is involved in the modulation of various follicular functions, including follicular development and ovulation. At present, the detailed molecular mechanisms by which IL6 regulates the event of ovulation remain to be elucidated. In the present study, primary and immortalized (SVOG) human granulosa-lutein (hGL) cells were used to investigate the effects of IL6 on the expression of prostaglandin-endoperoxide synthase 2 (PTGS2) and the subsequent synthesis of prostaglandin E2 (PGE2) and to investigate the underlying molecular mechanisms. We found that instead of classic signaling, IL6/sIL-6Rα trans-signaling induced the expression of PTGS2 and production of PGE2 in both SVOG cells and primary hGL cells. Moreover, IL6/sIL-6Rα activated the phosphorylation of Janus activated kinase 2 (JAK2) and signal transducer and activator of transcription 3 (STAT3), which in turn induced STAT3 nuclear translocation. Additionally, these effects were suppressed by the addition of inhibitors (AG490 for JAK2 and C188-9 for STAT3) and by the siRNA-mediated knockdown of STAT3. Additionally, suppressor of cytokine signaling 3 (SOCS3) acts as a negative-feedback regulator in IL6/sIL-6Rα-induced cellular activities, including the activation and nuclear translocation of STAT3, upregulation of PTGS2 expression, and increase in PGE2 production in SVOG cells. In conclusion, IL6 trans-signaling upregulates the expression of PTGS2 and increases the production of PGE2 via the JAK2/STAT3/SOCS3 signaling pathway in hGL cells. Our findings provide insights into the molecular mechanisms by which IL6 trans-signaling may potentially modulate the event of ovulation in human ovaries.

Regenerative Response of Degenerate Human Nucleus Pulposus Cells to GDF6 Stimulation

Growth differentiation factor (GDF) family members have been implicated in the development and maintenance of healthy nucleus pulposus (NP) tissue, making them promising therapeutic candidates for treatment of intervertebral disc (IVD) degeneration and associated back pain. GDF6 has been shown to promote discogenic differentiation of mesenchymal stem cells, but its effect on NP cells remains largely unknown. Our aim was to investigate GDF6 signalling in adult human NP cells derived from degenerate tissue and determine the signal transduction pathways critical for GDF6-mediated phenotypic changes and tissue homeostatic mechanisms. This study demonstrates maintained expression of GDF6 receptors in human NP and annulus fibrosus (AF) cells across a range of degeneration grades at gene and protein level. We observed an anabolic response in NP cells treated with recombinant GDF6 (increased expression of matrix and NP-phenotypic markers; increased glycosaminoglycan production; no change in catabolic enzyme expression), and identified the signalling pathways involved in these responses (SMAD1/5/8 and ERK1/2 phosphorylation, validated by blocking studies). These findings suggest that GDF6 promotes a healthy disc tissue phenotype in degenerate NP cells through SMAD-dependent and -independent (ERK1/2) mechanisms, which is important for development of GDF6 therapeutic strategies for treatment of degenerate discs.

BMP-6 and SMAD4 gene expression is altered in cumulus cells from women with endometriosis-associated infertility

INTRODUCTION

Oocyte competence and quality depend on communication between the oocyte and the cumulus and theca cells. In the preantral phase, the members of the transforming growth factor β (TGF-β) superfamily are responsible for this communication and play an important role in folliculogenesis. Members of the TGF-β superfamily are related to endometriosis (overexpression in the ectopic endometrium); however, few studies have explored these proteins as influencing fertility in endometriosis. Considering endometriosis-related infertility and to better understand the role of the TGF-β superfamily members in the antral phase in women with endometriosis, this research investigated the gene expression of the genes for ligands AMH, BMP-6, GDF-9, INHA, INHBB, and TGFβ3; receptors AMHR2, BMPR2, and TGFβR3; and intracellular signalling: SMAD3 and SMAD4.

MATERIAL AND METHODS

The gene expression of AMH, BMP-6, GDF-9, INHA, INHBB, TGFβ3, AMHR2, BMPR2, TGFβR3, SMAD3, and SMAD4 in cumulus cells was investigated through quantitative real-time PCR in a case-control study including infertile women with and without peritoneal endometriosis undergoing in vitro fertilization.

RESULTS

Age and outcomes of assisted reproduction were similar between the groups (P > .05). However, women with endometriosis showed reduced expression of BMP-6 and SMAD4 (P < .05) in cumulus cells compared with the control group, other genes did not present altered gene expression in women with endometriosis (P > .05).

CONCLUSIONS

The reduced expression of BMP-6 and SMAD4 in women with peritoneal endometriosis compared with the control group indicates that granulosa (cumulus) cell function could be altered in these women.

Neurotrophins and glial cell line-derived neurotrophic factor in the ovary: physiological and pathophysiological implications

BACKGROUND

Neurotrophins [nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), neurotrophin-3 (NT-3), and neurotrophin-4 (NT-4)] and glial cell line-derived neurotrophic factor (GDNF) are soluble polypeptide growth factors that are widely recognized for their roles in promoting cell growth, survival and differentiation in several classes of neurons. Outside the nervous system, neurotrophin (NT) and GDNF signaling events have substantial roles in various non-neural tissues, including the ovary.

OBJECTIVE AND RATIONALE

The molecular mechanisms that promote and regulate follicular development and oocyte maturation have been extensively investigated. However, most information has been obtained from animal models. Even though the fundamental process is highly similar across species, the paracrine regulation of ovarian function in humans remains poorly characterized. Therefore, this review aims to summarize the expression and functional roles of NTs and GDNF in human ovarian biology and disorders, and to describe and propose the development of novel strategies for diagnosing, treating and preventing related abnormalities.

SEARCH METHODS

Relevant literature in the English language from 1990 to 2018 describing the role of NTs and GDNF in mammalian ovarian biology and phenotypes was comprehensively selected using PubMed, MEDLINE and Google Scholar.

OUTCOMES

Studies have shown that the neurotrophins NGF, BDNF, NT-3 and NT-4 as well as GDNF and their functional receptors are expressed in the human ovary. Recently, gathered experimental data suggest putative roles for NT and GDNF signaling in the direct control of ovarian function, including follicle assembly, activation of the primordial follicles, follicular growth and development, oocyte maturation, steroidogenesis, ovulation and corpus luteum formation. Additionally, crosstalk occurs between these ovarian regulators and the endocrine signaling system. Dysregulation of the NT system may negatively affect ovarian function, leading to reproductive pathology (decreased ovarian reserve, polycystic ovary syndrome and endometriosis), female infertility and even epithelial ovarian cancers.

WIDER IMPLICATIONS

A comprehensive understanding of the expression, actions and underlying molecular mechanisms of the NT/GDNF system in the human ovary is essential for novel approaches to therapeutic and diagnostic interventions in ovarian diseases and to develop more safe, effective methods of inducing ovulation in ART in the treatment of female infertility.

TGF-β1 promotes vitamin D-induced prostaglandin E2 synthesis by upregulating vitamin D receptor expression in human granulosa-lutein cells

There is increasing evidence showing the importance of vitamin D (Vit D) and its nuclear receptor, the Vit D receptor (VDR), in female reproductive health. Transforming growth factor-β1 (TGF-β1) and its functional receptors are expressed in human oocytes and granulosa cells that participate in follicular development and ovulation. Recently, Sma- and Mad-related protein 3 (SMAD3; a downstream effector of TGF-β1) has been proposed to mediate crosstalk between the Vit D and TGF-β1 signaling pathways, but this relationship has not been fully explored and has yet to be tested in human granulosa-lutein (hGL) cells. In this study, we showed that TGF-β1 significantly promoted the expression of VDR, and this stimulatory effect occurred through the activin receptor-like kinase 5 type I receptor-mediated SMAD3 and ERK1/2 signaling pathways in hGL cells. Additionally, we showed that Vit D increased the expression of cyclooxygenase 2 (COX-2) and the synthesis of prostaglandin E2 (PGE2) in a time- and dose-dependent manner. Furthermore, we demonstrated a synergistic effect of TGF-β1 and Vit D on the expression of COX-2 and synthesis of PGE2, and this effect could be attenuated by silencing the expression of VDR. Our findings indicate that TGF-β1 upregulates the expression of VDR, which promotes Vit D-induced COX-2 expression and subsequent PGE2 production by activating the SMAD3 and ERK1/2 signaling pathways in hGL cells.

ALK4-SMAD3/4 mediates the effects of activin A on the upregulation of PAI-1 in human granulosa lutein cells

In the mammalian ovary, the proteolysis of the extracellular matrix is dynamically regulated by plasminogen activator and plasminogen activator inhibitor (PAI), and it is a critical event that influences various physiological and pathological processes. Activin A is a member of the transforming growth factor-β superfamily and is expressed at a high level in human luteal cells that play an essential role in the regulation of the luteal function. At present, it is not known whether activin A can regulate the expression and production of PAI in human granulosa lutein (hGL) cells. The present study aimed to examine the effects of activin A on the expression and production of intraovarian PAI-1 and the underlying molecular mechanisms. Using primary and immortalized hGL cells as the cell model, we demonstrated that activin A upregulated the expression of PAI-1 and increased the production of PAI-1 in an autocrine/paracrine manner. Additionally, using a dual inhibition approach (molecular inhibitors and siRNA-mediated knockdown), we showed that this biological function is mediated by the ALK4-mediated SMAD3-SMAD4-dependent signaling pathway. Our findings suggest that activin A may be involved in the regulation of luteal function via the induction of PAI-1 expression and an increase in PAI-1 production.

Regulatory expression of bone morphogenetic protein 6 by 2,2'-dipyridyl

BACKGROUND

Expression of hepcidin, a hormone produced by hepatocytes which negatively regulates the circulating iron levels, is known to be positively regulated by BMP6, a member of transforming growth factor (TGF)-β family. Previous studies have shown that iron status is sensed by sinusoidal endothelial cells of hepatic lamina, leading to the modulation of BMP6 expression.

METHODS

ISOS-1, HUVEC, F-2, and SK-HEP1 endothelial cells were treated with either iron or 2,2'-dipyridyl (2DP), a cell-permeable iron-chelator, and expression level of Bmp6 was examined. To identify factors affecting Bmp6 transcription, stimulus screening for regulator of transcription (SSRT) was developed.

RESULTS

Treatment with iron slightly increased the expression levels of Bmp6, while 2DP unexpectedly increased Bmp6 expression in a dose-dependent manner. 2DP-induced Bmp6 expression was resistant to co-treatment with iron. 2DP-induced Bmp6 expression was also detected in HUVEC, F-2 cells, and SK-HEP1 cells. Luciferase-based reporter assays indicated that forced expression of JunB increased the transcription of Bmp6. 2DP induced phosphorylation of JunB; co-treatment with SP600125 blocked the 2DP-induced Bmp6 expression partially. JunB-induced Bmp6 transcription was not affected by mutations of putative JunB-responsive elements. Some endoplasmic reticulum stress inducers increased the expression of Bmp6. SSRT revealed pathways regulating Bmp6 transcription positively and negatively. Hepa1-6 liver cells and C2C12 myogenic cells were prone to 2DP induced Bmp6 expression.

CONCLUSIONS

The present study reveals non‑iron-regulated Bmp6 expression in endothelial cells.

GENERAL SIGNIFICANCE

Regulatory expression of Bmp6 may be important as a key step for fine tuning of BMP activity.

Genes regulating hormone stimulus and response to protein signaling revealed differential expression pattern during porcine oocyte in vitro maturation, confirmed by lipid concentration

Genes influencing oocyte maturation may be valuable for predicting their developmental potential, as well as discerning the mechanistic pathways regulating oocyte development. In the presented research microarray gene expression analysis of immature and in vitro matured porcine oocytes was performed. Two groups of oocytes were compared in the study: before (3 × n = 50) and after in vitro maturation (3 × n = 50). The selection of viable oocytes was performed using the brilliant cresyl blue (BCB) test. Furthermore, microarrays and RT-qPCR was used to analyze the transcriptome of the oocytes before and after IVM. The study focused on the genes undergoing differential expression in two gene-ontology groups: “Cellular response to hormone stimulus” and “Cellular response to unfolded protein”, which contain genes that may directly or indirectly be involved in signal transduction during oocyte maturation. Examination of all the genes of interest showed a lower level of their expression after IVM. From the total number of genes in these gene ontologies ten of the highest change in expression were identified: FOS, ID2, BTG2, CYR61, ESR1, AR, TACR3, CCND2, EGR2 and TGFBR3. The successful maturation of the oocytes was additionally confirmed with the use of lipid droplet assay. The genes were briefly described and related to the literature sources, to investigate their potential roles in the process of oocyte maturation. The results of the study may serve as a basic molecular reference for further research aimed at improving the methods of oocyte in vitro maturation, which plays an important role in the procedures of assisted reproduction.

The Expression of ERK1/2 in Female Yak (Bos grunniens) Reproductive Organs

The main reproductive organs undergo different histological appearances and physiological processes under different reproductive statuses. The variation of these organs depends on a delicate regulation of cell proliferation, differentiation, and apoptosis. Extracellular signal-regulated kinases1/2 (ERK1/2) are members of the mitogen-activated protein kinase (MAPK) super family. They have important roles in regulating various biological processes of different cells, tissues, and organ types. Activated ERK1/2 generally promotes cell survival, but under certain conditions, ERK1/2 also have the function of inducing apoptosis. It is widely believed that ERK1/2 play a significant role in regulating the reproductive processes of mammals. The goal of our research is to investigate the expression and distribution of ERK1/2 in the yak's main reproductive organs during different stages. In the present study, samples of the ovary, oviduct, and uterus of 15 adult female yak were collected and used in the experiment. The ERK1/2 proteins, localization, and quantitative expression of their mRNA were investigated using immunohistochemistry (IHC), western blot (WB) and relative quantitative real-time polymerase chain reaction (RT-PCR). The results indicated that ERK1/2 proteins and their mRNA were highly expressed in the ovary of the luteal phase and gestation period, in the oviduct of the luteal phase, and in the uterus of the luteal phase and gestation period. Immunohistochemical analysis revealed a strong distribution of ERK1/2 proteins in follicular granulosa cells, granular luteal cells, villous epithelial cells of the oviduct, endometrial glandular epithelium, and luminal epithelium. These results demonstrated that the expression of ERK1 and ERK2 proteins and their mRNA in the yak's ovary, oviduct, and uterus varies with the stage of the reproductive cycle. The variation character of ERK1 and ERK 2 expression in the yak's main reproductive organs during different stages implies that they play an important role in regulating the reproductive function under different physiological statuses.

Bone morphogenetic protein 6 affects cell-cell communication by altering the expression of Connexin43 in human granulosa-lutein cells

Connexin 43 (Cx43)-coupled gap junctions in granulosa cells play an important role in follicular development, oocyte maturation, and corpus luteum maintenance. Bone morphogenetic protein 6 (BMP6) is highly expressed in human oocytes and granulosa cells and is involved in the regulation of female reproduction. Currently, whether oocyte- and granulosa cell-derived BMP6 affects the expression of Cx43 and its related gap junction intercellular communication (GJIC) activity in human granulosa cells remains unknown. In this study, we demonstrate that BMP6 treatment significantly suppressed the expression of Cx43 in both primary and immortalized (SVOG) human granulosa-lutein cells. Using both pharmacological inhibitors and small interfering RNA-mediated knockdown approaches, we demonstrate that ALK2 and ALK3 BMP type I receptors are involved in BMP6-induced suppressive effects on Cx43 expression and GJIC activity in SVOG cells. Furthermore, these cellular activities are most likely mediated by the SMAD1/SMAD5-SMAD4-dependent signaling pathway. Notably, the ChIP analyses demonstrated that phosphorylated SMADs could bind to human Cx43 promoter. Our findings provide new insight into the molecular mechanisms by which an intrafollicular growth factor regulates cell-cell communication in human granulosa cells.

CD24: a marker of granulosa cell subpopulation and a mediator of ovulation

Granulosa cells (GCs) play a critical role in driving the formation of ovarian follicles and building the cumulus-oocyte complex surrounding the ovum. We are particularly interested in assessing oocyte quality by examining the detailed gene expression profiles of human cumulus single cells. Using single-cell RNAseq techniques, we extensively investigated the single-cell transcriptomes of the cumulus GC populations from two women with normal ovarian function. This allowed us to elucidate the endogenous heterogeneity of GCs by uncovering the hidden GC subpopulation. The subsequent validation results suggest that CD24(+) GCs are essential for triggering ovulation. Treatment with human chorionic gonadotropin (hCG) significantly increases the expression of CD24 in GCs. CD24 in cultured human GCs is associated with hCG-induced upregulation of prostaglandin synthase (ARK1C1, PTGS2, PTGES, and PLA2G4A) and prostaglandin transporter (SLCO2A1 and ABCC4) expression, through supporting the EGFR-ERK1/2 pathway. In addition, it was observed that the fraction of CD24(+) cumulus GCs decreases in PCOS patients compared to that of controls. Altogether, the results support the finding that CD24 is an important mediator of ovulation and that it may also be used for therapeutic target of ovulatory disorders.

The balance of Bmp6 and Wnt10b regulates the telogen-anagen transition of hair follicles

BACKGROUND

The periodic growth of hair follicles is regulated by the balance of activators and inhibitors. The BMP signaling pathway plays an important role during hair follicle regeneration, but the exact BMP protein that controls this process has not been revealed.

METHODS

The expression of BMP6 was determined via in situ hybridization and immunofluorescence. The in vivo effect of BMP6 overexpression was studied by using a previously established adenovirus injection model. The hair follicle regeneration was assessed by gross observation, H&E staining and 5-bromo-2-deoxyuridine (BrdU) tracing. The expression patterns of BMP6 signaling and Wnt10b signaling in both AdBMP6-treated and AdWnt10b-treated skins were determined by in situ hybridization and immunofluorescence.

RESULTS

BMP6 was expressed differently in the stages of hair follicle cycle. The telogen-anagen transition of hair follicles was inhibited by adenovirus-mediated overexpression of BMP6. In the in vivo model, the BMP6 signaling was inhibited by Wnt10b and the Wnt10b signaling was inhibited by BMP6. The activation of hair follicle stem cells (HFSCs) was also competitively regulated by Wnt10b and BMP6.

CONCLUSIONS

Combined with previously reported data of Wnt10b, our findings indicate that BMP6 and Wnt10b are major inhibitors and activators respectively and their balance regulates the telogen-anagen transition of hair follicles. To the best of our knowledge, our data provide previously unreported insights into the regulation of hair follicle cycling and provide new clues for the diagnosis and therapies of hair loss.