Paracrine regulation of ovarian granulosa cell differentiation by stanniocalcin (STC) 1: mediation through specific STC1 receptors

Cloning of STC-1 and analysis of its differential expression in Hezuo pig

The purpose of this study was to examine STC-1's structure, function, and differential expression in large and miniature pigs. We cloned the Hezuo pig's coding sequence, compared its homology, and used bioinformatics to assess the structure. RT-qPCR and Western blot were used to detect the expression in ten tissues of Hezuo pig and Landrace pig. The results showed that Hezuo pig was most closely related to Capra hircus and most distantly related to Danio rerio. The protein STC-1 has a signal peptide and its secondary structure is dominated by the alpha helix. The mRNA expression in the spleen, duodenum, jejunum, and stomach of Hezuo pigs was higher than that of Landrace pigs. And except for heart and duodenum, expression of the protein in Hezuo pig was higher than in another. In conclusion, STC-1 is highly conserved among different breeds of pigs, and the expression and distribution of its mRNA and protein are different in large and miniature pigs. This work can lay the foundation for future study into the mechanism of action of STC-1 in Hezuo pigs and the enhancement of breeding in miniature pigs.

Molecular cloning and characterization of STC1 gene and its functional analyses in yak (Bos grunniens) cumulus granulosa cells

Cumulus granulosa cells (CGCs), an important type of ovarian somatic cells, carries out various functions related to oogenesis, follicular development, and steroidogenesis. Studying the biological mechanisms involved in the development and function of CGCs makes a great contribution to understanding the reproductive regulation in female animals. Stanniocalcin-1 (STC1) is an important Ca2+-regulated glycoprotein hormone that exhibits high expression levels in ovaries. In this study, we cloned the coding sequence of the yak STC1, predicted the structure of STC1 protein, detected the expression and localization of STC1 in yak ovaries, and analyzed the functions of STC1 in yak CGCs. The CDS (coding sequence) region of yak STC1 gene was found to be 744 bp and encoded 247 amino acids. Homology comparison revealed that STC1 protein was highly conserved among mammals. The STC1 mRNA displayed dynamic expression profiles in different stages of yak ovaries, and the highest expression was found in the follicular phase. Regarding localization, STC1 protein was widely distributed in various kinds of yak ovarian cells, including oocytes, mural granulosa cells, CGCs, and thecal cells. Repressing the expression of STC1 resulted in defective proliferation and survival of yak CGCs. In addition, knockdown the expression of STC1 repressed the secretion of progesterone and promoted the secretion of estrogen. Overexpression of STC1 partially rescued the proliferation of CGCs and resulted in opposite effects on the secretion of progesterone and estrogen. Several apoptosis and steroidogenesis-related genes, including BAX, BCL2, HSD3B1, HSD17B1, CYP11A1 and CYP17A1 showed altered expressions after repressing or increasing the expression of STC1 in yak CGCs. To the best of our knowledge, this study is the first to focus on the role of STC1 in yak CGCs, and the outcomes offer fresh insights into the mechanism governing yak reproduction.

Integrative analyses of the mRNA expression profile reveal the involvement of STC1 in chicken folliculogenesis

Efficient ovarian follicle development, maturation, and ovulation are critical for egg production performance. Previous research has underscored the importance of messenger RNAs (mRNAs) in regulating development and folliculogenesis in chicken ovarians. However, the molecular mechanism is not fully understood, especially in the late period of the laying cycle. In the present study, ovarian tissues from 80-week-old Hy-Line Brown layers (three with high and three with low rates of egg laying) were collected for transcriptome sequencing. A total of 306 differentially expressed genes (DEGs) were identified in this study, at a false discovery rate (FDR)-corrected P-value < 0.05 and a log2|fold change| (log2|FC|) ≥1.5. Among these DEGs, stanniocalcin 1 (STC1) was mainly related to cellular processes, single-organism processes, biological regulation, metabolic processes, developmental processes, and reproductive processes. Then, we further investigated the regulation of STC1 during chicken follicle development and found that STC1 inhibited the proliferation and stimulated the apoptosis of follicular granulosa cells (GCs), and decreased the expression of progesterone (P4) and estradiol (E2). Collectively, these results suggest that STC1 plays an important role in chicken follicle development by decreasing GC proliferation and steroidogenesis and stimulating GC apoptosis. This study contributes to the understanding of the reproductive biology of laying hens in the late period of the laying cycle and further lays a foundation for the improvement of egg production in poultry breeding.

Transcriptomic diversification of granulosa cells during follicular development between White Leghorn and Silky Fowl hens

Egg production rate in chicken is related to the continuity of follicle development. In this study, we found that the numbers of white prehierarchical, dominant, and yellow preovulatory follicles in the high-yielding layer breed, White Leghorn (WL), were significantly higher than those in the low egg-yielding variety, Silky Fowl (SF). The proliferation and differentiation of granulosa cells (GCs) play an important role in follicle maturation. Histological observation revealed a large number of melanocytes in the outer granulosa layer of follicles in SF but not in WL. Finally, RNA-sequencing was used to analyze the gene expression profiles and pathways of the GC layer in the follicles in both WL and SF hens. Transcriptome analysis of prehierarchical GCs (phGCs) and preovulatory GCs (poGCs) between WL and SF showed that steroid hormone-, oxytocin synthesis-, tight junction-, and endocytosis-related genes were expressed at higher levels in WL phGCs than in SF phGCs, whereas the insulin signaling pathway- and vascular smooth muscle contraction-related genes were upregulated in SF phGCs. Fatty acid synthesis, calcium signaling, and Wnt signaling pathway-related genes were expressed at higher levels in WL poGCs than in SF poGCs; however, adrenergic signaling, cGMP-PKG, and melanogenesis-related genes were upregulated in SF poGCs. These results indicate that genes that promote GC proliferation and secretion of various sex hormones are more active in WL than in SF hens. The upregulated signaling pathways in SF help in providing energy to GCs and for angiogenesis and melanogenesis. In vitro experiments confirmed that both the proliferation of poGCs and synthesis of reproductive hormones were higher in WL than in SF hens.

Analysis on the desert adaptability of indigenous sheep in the southern edge of Taklimakan Desert

The southern margin of the Taklimakan Desert is characterized by low rainfall, heavy sandstorms, sparse vegetation and harsh ecological environment. The indigenous sheep in this area are rich in resources, with the advantages of perennial estrus and good resistance to stress in most sheep. Exploring the molecular markers of livestock adaptability in this environment will provide the molecular basis for breeding research to cope with extreme future changes in the desert environment. In this study, we analyzed the population genetic structure and linkage imbalance of five sheep breeds with three different agricultural geographic characteristics using four complementary genomic selection signals: fixation index (FST), cross-population extended haplotype homozygosity (xp-EHH), Rsb (extended haplotype homozygosity between-populations) and iHS (integrated haplotype homozygosity score). We used Illumina Ovine SNP 50K Genotyping BeadChip Array, and gene annotation and enrichment analysis were performed on selected regions of the obtained genome. The ovary of Qira Black sheep (Follicular phase, Luteal phase, 30th day of pregnancy, 45th day of pregnancy) was collected, and the differentially expressed genes were screened by transcriptomic sequencing. Genome-wide selective sweep results and transcriptome data were combined for association analysis to obtain candidate genes associated with perennial estrus and stable reproduction. In order to verify the significance of the results, 15 resulting genes were randomly selected for fluorescence quantitative analysis. The results showed that Dolang sheep and Qira Black sheep evolved from Kazak sheep. Linkage disequilibrium analysis showed that the decay rate of sheep breeds in the Taklimakan Desert was higher than that in Yili grassland. The signals of FST, xp-EHH, Rsb and iHS detected 526, 332, 308 and 408 genes, respectively, under the threshold of 1% and 17 overlapping genes under the threshold of 5%. A total of 29 genes were detected in association analysis of whole-genome and transcriptome data. This study reveals the genetic mechanism of perennial estrus and environmental adaptability of indigenous sheep breeds in the Taklimakan Desert. It provides a theoretical basis for the conservation and exploitation of genetic resources of indigenous sheep breeds in extreme desert environment. This provides a new perspective for the quick adaptation of sheep and other mammals to extreme environments and future climate changes.

Stanniocalcin 1 promotes metastasis, lipid metabolism and cisplatin chemoresistance via the FOXC2/ITGB6 signaling axis in ovarian cancer

BACKGROUND

Stanniocalcin 1 (STC1) plays an integral role in ovarian cancer (OC). However, the functional role of STC1 in metastasis, lipid metabolism and cisplatin (DDP) chemoresistance in OC is not fully understood.

METHODS

Single-cell sequencing and IHC analysis were performed to reveal STC1 expression profiles in patient tissues. Metastasis, lipid metabolism and DDP chemoresistance were subsequently assessed. Cell-based in vitro and in vivo assays were subsequently conducted to gain insight into the underlying mechanism of STC1 in OC.

RESULTS

Single-cell sequencing assays and IHC analysis verified that STC1 expression was significantly enhanced in OC tissues compared with para-carcinoma tissues, and it was further up-regulated in peritoneal metastasis tissues compared with OC tissues. In vitro and in vivo experiments demonstrated that STC1 promoted metastasis, lipid metabolism and DDP chemoresistance in OC. Simultaneously, STC1 promoted lipid metabolism by up-regulating lipid-related genes such as UCP1, TOM20 and perilipin1. Mechanistically, STC1 directly bound to integrin β6 (ITGB6) to activate the PI3K signaling pathway. Moreover, STC1 was directly regulated by Forkhead box C2 (FOXC2) in OC. Notably, targeting STC1 and the FOXC2/ITGB6 signaling axis was related to DDP chemoresistance in vitro.

CONCLUSIONS

Overall, these findings revealed that STC1 promoted metastasis, lipid metabolism and DDP chemoresistance via the FOXC2/ITGB6 signaling axis in OC. Thus, STC1 may be used as a prognostic indicator in patients with metastatic OC. Meanwhile, STC1 could be a therapeutic target in OC patients, especially those who have developed chemoresistance to DDP.

Expression profiling of ovarian BMP antagonists reveals the potential interaction between TWSG1 and the chordin subfamily in the ovary

The TGF-β superfamily members and their antagonists comprise an indispensable system that controls mammalian ovarian development in a sophisticated manner. In contrast to a plethora of studies on the ovary-expressed TGF-β superfamily members, knowledge regarding their antagonists, including their expression profiles and antagonism preferences, is still lacking. Using quantitative PCR in rats and transcriptomic dataset comparisons in mice and humans, we set out to characterize the relative expression levels of most antagonists in the mammalian ovary. We found that Twsg1 and Nbl1 are the most abundant BMP antagonists expressed in the rodent and human ovaries, respectively. TWSG1 has been reported to have synergistic action with the chordin subfamily, including CHRD and CHRDL1, the genes of which also showed moderate expression in the mammalian ovary. Therefore, their ovarian expression profiles and antagonisms against the ovary-expressed TGF-β superfamily members were further characterized. Bioactivity tests indicated that TWSG1 alone can directly inhibit the signaling of BMP6 or BMP7. In addition, it can further enhance the antagonizing ability of CHRD towards BMP2, BMP4, BMP7 and GDF5, or CHRDL1's antagonism towards BMP2, BMP4, GDF5 and activin A. In combination with their distinct transcript profiles in ovarian compartments, our findings suggest that TWSG1 may work coordinately with CHRD within theca/interstitial shells and also with CHRDL1 in developing granulosa cells; these interactions would modulate the intraovarian functions of the TGF-β superfamily members, such as the control of progesterone production.

Stanniocalcin-1 in the female reproductive system and pregnancy

BACKGROUND

Stanniocalcin-1 (STC-1) is a widely expressed glycoprotein hormone involved in a diverse spectrum of physiological and pathophysiological processes including angiogenesis, mineral homeostasis, cell proliferation, inflammation and apoptosis. Over the last 20 years, numerous studies have reported STC-1 expression within female reproductive tissues including the uterus, ovaries and placenta and implicated STC-1 in processes such as ovarian follicular development, blastocyst implantation, vascular remodelling in early pregnancy and placental development. Notably, dysregulation of STC-1 within reproductive tissues has been linked to the onset of severe reproductive disorders including endometriosis, polycystic ovary syndrome, poor trophoblast invasion and placental perfusion in early pregnancy. Furthermore, significant changes in tissue expression and in maternal systemic concentration take place throughout pregnancy and further substantiate the vital role of this protein in reproductive health and disease.

OBJECTIVE AND RATIONALE

Our aim is to provide a comprehensive overview of the existing literature, to summarise the expression profile and roles of STC-1 within the female reproductive system and its associated pathologies. We highlight the gaps in the current knowledge and suggest potential avenues for future research.

SEARCH METHODS

Relevant studies were identified through searching the PubMed database using the following search terms: ‘stanniocalcin-1’, ‘placenta’, ‘ovary’, ‘endometrium’, ‘pregnancy’, ‘reproduction’, ‘early gestation’. Only English language papers published between 1995 and 2020 were included.

OUTCOMES

This review provides compelling evidence of the vital function that STC-1 plays within the female reproductive system. The literature presented summarise the wide expression profile of STC-1 within female reproductive organs, as well as highlighting the putative roles of STC-1 in various functions in the reproductive system. Moreover, the observed link between altered STC-1 expression and the onset of various reproductive pathologies is presented, including those in pregnancy whose aetiology occurs in the first trimester. This summary emphasises the requirement for further studies on the mechanisms underlying the regulation of STC-1 expression and function.

WIDER IMPLICATIONS

STC-1 is a pleiotropic hormone involved in the regulation of a number of important biological functions needed to maintain female reproductive health. There is also growing evidence that dysregulation of STC-1 is implicated in common reproductive and obstetric disorders. Greater understanding of the physiology and biochemistry of STC-1 within the field may therefore identify possible targets for therapeutic intervention and/or diagnosis.

Characterization of stanniocalcin-1 expression in macrophage differentiation

Human stanniocalcin-1 (STC1) is a paracrine factor associated with inflammation and carcinogenesis. The role of STC1 in the pro- and anti-inflammatory functions of differentiating macrophage, however, is not clear. In this study, our data showed that phorbol 12-myristate 13-acetate (PMA) treatment induced human leukemia monocytic cells (ThP-1) differentiation to M0 macrophages. The differentiation was accompanied by a significant increase in the mRNA expression levels of STC1, the pro-inflammatory cytokine TNFα, and anti-inflammatory markers, CD163 & CD206. An intermitted removal of PMA treatment reduced the mRNA levels of STC1 and TNFα but had no noticeable effects on the anti-inflammatory markers. The correlation in the expression of STC1 and pro-inflammatory markers in differentiating macrophages was investigated, using siRNA_STC1-transfected PMA-induced cells. Consistently, the transcripts levels of TNFα and IL-6 were significantly reduced. Moreover, LPS/IFNγ-induced M1-polarization showed remarkably higher expression levels of STC1 than IL-4/IL-13-induced M2-macrophages and PMA-induced M0-macrophages. Transcriptomic analysis of siRNA_STC1-transfected M1-polarized cells revealed an upregulation of TBC1 domain family member 3 (TBC1D3G). The gene regulates the payload of macrophage-released extracellular vesicles to mediate inflammation. The conditioned media from siRNA_STC1-transfected M1-polarized cells were found to reduce Hep3B cell motility. The data suggest that the expression of STC1 were associated with macrophage differentiation, but preferentially to M1 polarization.

Effects of miR-101-3p on goat granulosa cells in vitro and ovarian development in vivo via STC1

Background

MiRNAs act as pivotal post-transcriptional gene mediators in the regulation of diverse biological processes, including proliferation, development and apoptosis. Our previous study has showed that miR-101-3p is differentially expressed in dairy goat ovaries compared single with multiple litters. The objective of this research was to explore the potential function and molecular mechanism of miR-101-3p via its target STC1 in goat ovarian growth and development.

Results

cDNA libraries were constructed using goat granulosa cells transfected with miR-101-3p mimics and negative control by RNA-sequencing. In total, 142 differentially expressed unigenes (DEGs) were detected between two libraries, including 78 down-regulated and 64 up-regulated genes. GO and KEGG enrichment analysis showed the potential impacts of DEGs on ovarian development. STC1 was singled out from DEGs for further research owing to it regulates reproductive-related processes. In vitro, bioinformatics analysis and 3′-UTR assays confirmed that STC1 was a target of miR-101-3p. ELISA was performed to detect the estrogen (E2) and progesterone (P4) levels. CCK8, EdU and flow cytometry assays were performed to detect the proliferation and apoptosis of granulosa cells. Results showed that miR-101-3p regulated STAR, CYP19A1, CYP11A1 and 3β-HSD steroid hormone synthesis-associated genes by STC1 depletion, thus promoted E2 and P4 secretions. MiR-101-3p also affected the key protein PI3K, PTEN, AKT and mTOR in PI3K-AKT pathway by STC1, thereby suppressing proliferation and promoting apoptosis of granulosa cells. In vivo, the distribution and expression levels of miR-101-3p in mouse ovaries were determined through fluorescence in situ hybridisation (FISH). Immunohistochemistry results showed that STC1 expression was suppressed in mouse ovaries in miR-101-3p-agonist and siRNA-STC1 groups. Small and stunted ovarian fragments, decreased numbers of follicles at diverse stages were observed using Hematoxylin-eosin (HE) staining, thereby showing unusual ovarian development after miR-101-3p overexpression or STC1 depletion. Inhibition of miR-101-3p manifested opposite results.

Conclusions

Taken together, our results demonstrated a regulatory mechanism of miR-101-3p via STC1 in goat granulosa cells, and offered the first in vivo example of miR-101-3p and STC1 functions required for ovarian development.

Expression, function and clinical application of stanniocalcin-1 in cancer

The glycoprotein stanniocalcin-1 functions as a regulatory endocrine hormone that maintains the balance of calcium and phosphorus in bony fish and as a paracrine/autocrine factor involved in many physiological/pathological processes in humans, including carcinogenesis. In this review, we provide an overview of (a) the possible mechanisms through which STC1 affects the malignant properties of cancer, (b) transcriptional and post-transcriptional regulation pathways of STC1 and (c) the potential clinical relevance of STC1 as a cancer biomarker and even a therapeutic target in the future. Exploring the role of STC1 in cancer development may provide a better understanding of the tumorigenesis process in humans and may facilitate finding an effective therapeutic method against cancer.

Transcriptomic Analysis of circRNAs and mRNAs Reveals a Complex Regulatory Network That Participate in Follicular Development in Chickens

Follicular development plays a key role in poultry reproduction, affecting clutch traits and thus egg production. Follicular growth is determined by granulosa cells (GCs), theca cells (TCs), and oocyte at the transcription, translation, and secretion levels. With the development of bioinformatic and experimental techniques, non-coding RNAs have been shown to participate in many life events. In this study, we investigated the transcriptomes of GCs and TCs in three different physiological stages: small yellow follicle (SYF), smallest hierarchical follicle (F6), and largest hierarchical follicle (F1) stages. A differential expression (DE) analysis, weighted gene co-expression network analysis (WGCNA), and bioinformatic analyses were performed. A total of 18,016 novel circular RNAs (circRNAs) were detected in GCs and TCs, 8127 of which were abundantly expressed in both cell types. and more circRNAs were differentially expressed between GCs and TCs than mRNAs. Enrichment analysis showed that the DE transcripts were mainly involved in cell growth, proliferation, differentiation, and apoptosis. In the WGCNA analysis, we identified six specific modules that were related to the different cell types in different stages of development. A series of central hub genes, including MAPK1, CITED4, SOD2, STC1, MOS, GDF9, MDH1, CAPN2, and novel_circ0004730, were incorporated into a Cytoscape network. Notably, using both DE analysis and WGCNA, ESR1 was identified as a key gene during follicular development. Our results provide valuable information on the circRNAs involved in follicle development and identify potential genes for further research to determine their roles in the regulation of different biological processes during follicle growth.

Stanniocalcin-1 Alleviates Contrast-Induced Acute Kidney Injury by Regulating Mitochondrial Quality Control via the Nrf2 Pathway

Contrast-induced acute kidney injury (CI-AKI) is the third common cause of acute kidney injury (AKI), which is associated with poor short- and long-term outcomes. Currently, effective therapy strategy for CI-AKI remains lacking. Stanniocalcin-1 (STC1) is a conserved glycoprotein with antiapoptosis and anti-inflammatory functions, but the role of STC1 in controlling CI-AKI is unknown. Here, we demonstrated a protective role of STC1 in contrast-induced injury in cultured renal tubular epithelial cells and CI-AKI rat models. Recombinant human STC1 (rhSTC1) regulated mitochondrial quality control, thus suppressing contrast-induced mitochondrial damage, oxidative stress, inflammatory response, and apoptotic injury. Mechanistically, activation of the Nrf2 signaling pathway contributes critically to the renoprotective effect of STC1. Together, this study demonstrates a novel role of STC1 in preventing CI-AKI and reveals Nrf2 as a molecular target of STC1. Therefore, this study provides a promising preventive target for the treatment of CI-AKI.

New Insights Into Physiological and Pathophysiological Functions of Stanniocalcin 2

Stanniocalcin, a glycosylated peptide hormone, first discovered in a bony fish has originally been shown to play critical role in calcium and phosphate homeostasis. Two paralogs of stanniocalcin (STC1 and STC2) identified in mammals are widely expressed in variety of tissues. This review provides historical perspective on the discovery of fish and mammalian stanniocalcin, describes molecular regulation of STC2 gene, catalogs distribution as well as expression of STC2 in tissues, and provides key structural information known till date regarding mammalian STC2. Additionally, this mini review summarizes pivotal functions of STC2 in calcium and phosphate regulation, cytoprotection, cell development, and angiogenesis. Finally, STC2's role as a novel marker for human cancers has also been outlined. Reviewing these studies will provide an opportunity to understand STC2's structure, biological functions as well as key molecular pathways involving STC2, which will help us design innovative therapeutic interventions using this novel hormone.

Target prediction and validation of microRNAs expressed from FSHR and aromatase genes in human ovarian granulosa cells

MicroRNAs (miRNAs) are known post-transcriptional regulators of various biological processes including ovarian follicle development. We have previously identified miRNAs from human pre-ovulatory ovarian granulosa cells that are expressed from the intronic regions of two key genes in normal follicular development: FSH receptor (FSHR) and CYP19A1, the latter encoding the aromatase enzyme. The present study aims to identify the target genes regulated by these miRNAs: hsa-miR-548ba and hsa-miR-7973, respectively. The miRNAs of interest were transfected into KGN cell line and the gene expression changes were analyzed by Affymetrix microarray. Potential miRNA-regulated genes were further filtered by bioinformatic target prediction algorithms and validated for direct miRNA:mRNA binding by luciferase reporter assay. LIFR, PTEN, NEO1 and SP110 were confirmed as targets for hsa-miR-548ba. Hsa-miR-7973 target genes ADAM19, PXDN and FMNL3 also passed all verification steps. Additionally, the expression pattern of the miRNAs was studied in human primary cumulus granulosa cell culture in relation to the expression of their host genes and FSH stimulation. Based on our findings we propose the involvement of hsa-miR-548ba in the regulation of follicle growth and activation via LIFR and PTEN. Hsa-miR-7973 may be implicated in the modulation of extracellular matrix and cell-cell interactions by regulating the expression of its identified targets.

An integrated investigation of oocyte developmental competence: expression of key genes in human cumulus cells, morphokinetics of early divisions, blastulation, and euploidy

PURPOSE

To investigate the association of cumulus cell (CC)-related expression of a selected cluster of key genes (PTGS2, CAMK1D, HAS2, STC1, and EFNB2) with embryo development to blastocyst.

METHODS

Exploratory study at a private clinic. Eighteen advanced maternal age patients were enrolled (37.3 ± 4.0 years). Seventy-five cumuli were collected, whose oocytes resulted in either developmental arrest (N = 33) or blastocyst formation (N = 42). The noninvasive CC gene expression was combined with time-lapse morphokinetic parameters and, for blastocysts, with qPCR-based aneuploidy testing on trophectoderm biopsies.

RESULTS

The detection rate was 100% for all transcripts, but STC1 (96%) and CAMK1D (89%). Among amplified assays, CC mean expression levels of CAMK1D, PTGS2, and HAS2 were higher from oocytes that developed to blastocyst. No difference in CC key gene expression was reported between euploid (N = 21) and aneuploid (N = 21) blastocysts. Some timings of early embryo development were faster in embryos developing to blastocyst (time of pronuclei appearance and fading, division to two- and four-cells, first and second cell cycles). However, the generalized linear models outlined increasing CAMK1D expression levels as the strongest parameter associated with oocytes' developmental potential from both a general (AUC = 0.78 among amplified samples) and an intrapatient perspectives (AUC = 0.9 among patients obtaining ≥ 2 zygotes from the cohort with different developmental outcomes).

CONCLUSIONS

CAMK1D level of expression in CCs associated with blastocyst development. If confirmed from larger studies in wider populations of patients, the investigation of CC key gene expression might suit IVF clinics not adopting blastocyst culture. Future investigations should clarify the role of CAMK1D in ovarian physiology and could provide novel insights on how oocytes gain competence during folliculogenesis.

Insulin-Like Growth Factor Binding Proteins and IGFBP Proteases: A Dynamic System Regulating the Ovarian Folliculogenesis

The aim of the present article is to update our understanding of the expression of the insulin-like growth factor binding proteins (IGFBPs), IGFBP proteases and their implication in the different processes of ovarian folliculogenesis in mammals. In the studied species, IGFs and several small-molecular weight IGFBPs (in particular IGFBP-2 and IGFBP-4) are considered, respectively, as stimulators and inhibitors of follicular growth and maturation. IGFs play a key role in sensitizing ovarian granulosa cells to FSH action during terminal follicular growth. Concentrations of IGFBP-2 and IGFBP-4 in follicular fluid strongly decrease during follicular growth, leading to an increase in IGF bioavailability. Inversely, atresia is characterized by an increase of IGFBP-2 and IGFBP-4 levels, leading to a decrease in IGF bioavailability. Changes in intrafollicular IGFBPs content are due to variations in mRNA expression and/or proteolytic degradation by the pregnancy-associated plasma protein-A (PAPP-A), and likely participates in the selection of dominant follicles. The identification of PAPP-A2, as an IGFBP-3 and -5 protease, and stanniocalcins (STCs) as inhibitors of PAPP-A activity extends the IGF system. Studies on their implication in folliculogenesis in mammals are still in the early stages.

Identification of potential biomarkers in donor cows for in vitro embryo production by granulosa cell transcriptomics

The Ovum Pick Up-In vitro Production (OPU-IVP) of embryos is an advanced reproductive technology used in cattle production but the complex biological mechanisms behind IVP outcomes are not fully understood. In this study we sequenced RNA of granulosa cells collected from Holstein cows at oocyte aspiration prior to IVP, to identify candidate genes and biological mechanisms for favourable IVP-related traits in donor cows where IVP was performed separately for each animal. We identified 56 genes significantly associated with IVP scores (BL rate, kinetic and morphology). Among these, BEX2, HEY2, RGN, TNFAIP6 and TXNDC11 were negatively associated while Mx1 and STC1 were positively associated with all IVP scores. Functional analysis highlighted a wide range of biological mechanisms including apoptosis, cell development and proliferation and four key upstream regulators (COX2, IL1, PRL, TRIM24) involved in these mechanisms. We found a range of evidence that good IVP outcome is positively correlated with early follicular atresia. Furthermore we showed that high genetic index bulls can be used in breeding without reducing the IVP performances. These findings can contribute to the development of biomarkers from follicular fluid content and to improving Genomic Selection (GS) methods that utilize functional information in cattle breeding, allowing a widespread large scale application of GS-IVP.

Stanniocalcin-1 Hormone in Nonpreeclamptic and Preeclamptic Pregnancy: Clinical, Life-Style, and Genetic Modulators

CONTEXT AND OBJECTIVES

The study represents the first comprehensive analysis of Stanniocalcin-1 (STC1) hormone in human pregnancy, assessing clinical, lifestyle, and genetic determinants of circulating STC1 at term.

DESIGN, SETTING, AND PARTICIPANTS

Participants included women with (n = 50) and without (n = 316) preeclampsia (PE) at delivery, recruited in the REPROgrammed fetal and/or maternal METAbolism (REPROMETA) study (2006-2011, Estonia). Genetic association analysis combined PE cases (n = 597) and controls (n = 623) from the REPROMETA and Finnish Genetics of Preeclampsia Consortium (2008-2011) studies.

MAIN OUTCOME MEASURE(S)

Maternal postpartum plasma STC1 was measured by ELISA (n = 366) and placental STC1 gene expression by TaqMan quantitative RT-PCR (n = 120). Genotyping was performed using Sequenom MassArray.

RESULTS

Significantly higher STC1 plasma level was measured for the PE (median, 1952 pg/mL; 1030-4284 pg/mL) compared with non-PE group (median, 1562 pg/mL; 423-3781 pg/mL; P = 3.7 × 10-4, Mann-Whitney U test). Statistical significance was enhanced after adjustment for cofactors (linear regression, P = 1.8 × 10-6). STC1 measurements were negatively correlated with maternal smoking. Prepregnancy body mass index had a positive correlation with STC1 only among PE patients (r = 0.45; P = .001). The strongest genetic association with hormone concentrations was detected for STC1 single nucleotide polymorphisms rs3758089 (C allele: minor allele frequency, 5%; linear regression: β = 249.2 pg/mL; P = .014) and rs12678447 (G allele: minor allele frequency, 7%; β = 147.0 pg/mL; P = .082). rs12678447 placental genotypes were significantly associated with STC1 gene expression (P = .014). The REPROMETA/Finnish Genetics of Preeclampsia Consortium meta-analysis suggested an increased risk to develop late-onset PE for the rs12678447 G allele carriers (P = .05; odds ratio = 1.38 [0.98-1.93]).

CONCLUSIONS

Increased STC1 hormone represents a hallmark of late-onset PE. STC1 gene variants modulate placental gene expression and maternal hormone levels.

Stanniocalcin-1 expression in normal human endometrium and dysregulation in endometriosis

OBJECTIVE

To determine expression of stanniocalcin-1 (STC1) in human endometrium with and without endometriosis and its regulation by steroid hormones.

DESIGN

Laboratory study.

SETTING

University.

PATIENT(S)

Nineteen women with endometriosis and 33 control women.

INTERVENTION(S)

Endometrial biopsy and fluid sampling.

MAIN OUTCOME MEASURE(S)

Analysis of early secretory (ESE) and midsecretory (MSE) endometrial secretomes from fertile women with the use of nano-liquid chromatography-dual mass spectrometry; real-time quantitative polymerase chain reaction, and immunohistochemistry for STC1 and its receptor calcium-sensing receptor (CASR) mRNA and proteins in endometrium with and without endometriosis; evaluation of STC1 and CASR mRNA expression in endometrial stromal fibroblasts (eSF) from women with and without endometriosis decidualized with the use of E2P or 8-bromo-cyclic adenosine monophosphate (cAMP).

RESULT(S)

STC1 protein was strongly up-regulated in MSE versus ESE in endometrial fluid of fertile women. STC1 mRNA significantly increased in MSE from women with, but not from those without, endometriosis, compared with proliferative endometrium or ESE, with no significant difference throughout the menstrual cycle between groups. STC1 mRNA in eSF from control women increased >230-fold on decidualization with the use of cAMP versus 45-fold from women with endometriosis, which was not seen on decidualization with E2/P. CASR mRNA did not exhibit significant differences in any condition and was not expressed in isolated eSF. STC1 protein immunoexpression in eSF was significantly lower in women with endometriosis compared with control women.

CONCLUSION(S)

STC1 protein is significantly up-regulated in MSE endometrial fluid and is dysregulated in eutopic endometrial tissue from women with endometriosis. It is likely regulated by cAMP and may be involved in the pathogenesis of decidualization defects.

Severe Nephrotoxic Nephritis following Conditional and Kidney-Specific Knockdown of Stanniocalcin-1

BACKGROUND

Inflammation is the hallmark of nephrotoxic nephritis. Stanniocalcin-1 (STC1), a pro-survival factor, inhibits macrophages, stabilizes endothelial barrier function, and diminishes trans-endothelial migration of leukocytes; consistently, transgenic (Tg) overexpression of STC1 protects from nephrotoxic nephritis. Herein, we sought to determine the phenotype of nephrotoxic nephritis after conditional and kidney-specific knockdown of STC1.

METHODS

We used Tg mice that, express either STC1 shRNA (70% knockdown of STC1 within 4d) or scrambled shRNA (control) upon delivery of Cre-expressing plasmid to the kidney using ultrasound microbubble technique. Sheep anti-mouse GBM antibody was administered 4d after shRNA activation; and mice were euthanized 10 days later for analysis.

RESULTS

Serum creatinine, proteinuria, albuminuria and urine output were similar 10 days after anti-GBM delivery in both groups; however, anti-GBM antibody delivery to mice with kidney-specific knockdown of STC1 produced severe nephrotoxic nephritis, characterized by severe tubular necrosis, glomerular hyalinosis/necrosis and massive cast formation, while control mice manifested mild tubular injury and crescentic glomerulonephritis. Surprisingly, the expression of cytokines/chemokines and infiltration with T-cells and macrophages were also diminished in STC1 knockdown kidneys. Staining for sheep anti-mouse GBM antibody, deposition of mouse C3 and IgG in the kidney, and antibody response to sheep IgG were equal.

CONCLUSIONS

nephrotoxic nephritis after kidney-specific knockdown of STC1 is characterized by severe tubular and glomerular necrosis, possibly due to loss of STC1-mediated pro-survival factors, and we attribute the paucity of inflammation to diminished release of cytokines/chemokines/growth factors from the necrotic epithelium.

The Effects of Simazine, a Chlorotriazine Herbicide, on the Expression of Genes in Developing Male Xenopus laevis

Simazine was investigated for gene expression concurrent with simazine-induced phenotype changes during development of male Xenopus laevis. X. laevis tadpoles (Nieuwkoop-Faber stage 46) were exposed to 0.1, 1.2, 11.0 and 100.9 μg/L simazine for 100 days. The results showed that an increased mortality of X. laevis, decreased gonad weight and altered gonadosomatic index of males significantly (p<0.05) when exposed to simazine at 11.0 and 100.9 µg/L. Significant degeneration in testicular tissues was observed when tadpoles were exposed to simazine at 100.9 µg/L. To investigate the molecular mechanisms behind the testicular degeneration by simazine, we evaluated gene expression in animals treated with 100.9 µg/L simazine and found that 1,315 genes were significantly altered (454 upregulated, 861 downregulated). Genes involved in the cell cycle control, and amino acid metabolism pathways were significantly downregulated. These results indicate that simazine affects the related gene expressions which may be helpful for the understanding of the reason for the reproductive toxicity of simazine on male X. laevis.

Identification of Ran-binding protein M as a stanniocalcin 2 interacting protein and implications for androgen receptor activity

Stanniocalcin (STC), a glycoprotein hormone originally discovered in fish, has been implicated in calcium and phosphate homeostasis. While fishes and mammals possess two STC homologs (STC1 and STC2), the physiological roles of STC2 are largely unknown compared with those of STC1. In this study, we identified Ran-binding protein M (RanBPM) as a novel binding partner of STC2 using yeast two-hybrid screening. The interaction between STC2 and RanBPM was confirmed in mammalian cells by immunoprecipitation. STC2 enhanced the RanBPM-mediated transactivation of liganded androgen receptor (AR), but not thyroid receptor β, glucocorticoid receptor, or estrogen receptor β. We also found that AR interacted with RanBPM in both the absence and presence of testosterone (T). Furthermore, we discovered that STC2 recruits RanBPM/AR complex in T-dependent manner. Taken together, our findings suggest that STC2 is a novel RanBPM-interacting protein that promotes AR transactivation.

STC1 interference on calcitonin family of receptors signaling during osteoblastogenesis via adenylate cyclase inhibition

Stanniocalcin 1 (STC1) and calcitonin gene-related peptide (CGRP) are involved in bone formation/remodeling. Here we investigate the effects of STC1 on functional heterodimer complex CALCRL/RAMP1, expression and activity during osteoblastogenesis. STC1 did not modify CALCRL and ramp1 gene expression during osteoblastogenesis when compared to controls. However, plasma membrane spatial distribution of CALCRL/RAMP1 was modified in 7-day pre-osteoblasts exposed to either CGRP or STC1, and both peptides induced CALCRL and RAMP1 assembly. CGRP, but not STC1 stimulated cAMP accumulation in 7-day osteoblasts and in CALCRL/RAMP1 transfected HEK293 cells. Furthermore, STC1 inhibited forskolin stimulated cAMP accumulation of HEK293 cells, but not in CALCRL/RAMP1 transfected HEK293 cells. However, STC1 inhibited cAMP accumulation in calcitonin receptor (CTR) HEK293 transfected cells stimulated by calcitonin. In conclusion, STC1 signals through inhibitory G-protein modulates CGRP receptor spatial localization during osteoblastogenesis and may function as a regulatory factor interacting with calcitonin peptide members during bone formation.

Stanniocalcin-1 promotes metastasis in a human breast cancer cell line through activation of PI3K

Stanniocalcin-l (STC-1) is a secreted glycoprotein hormone that regulates calcium and phosphate homeostasis. STC-1 expression is upregulated in several cancers including breast cancer, and has been shown to be prognostic. Although these clinical observations implicate STC-1 as a potential tumor marker, it is still unclear whether STC-1 confers a malignant phenotype. In this study, this question was addressed by overexpressing STC-1 in the human breast cancer cell line MDA-MB-231 and examining the resultant phenotype in vitro and in vivo. Overexpression of STC-1 enhanced invasiveness of MDA-MB-231 cells in vitro and promoted their lung metastasis in vivo, while having no effect on proliferation, adhesion, or proteinase activity. The addition of soluble STC-1 to MDA-MB-231 cultures resulted in the activation of the phosphoinositide 3-kinase (PI3K)/Akt signaling pathway, suggesting a mechanistic basis for the observed increases in cell motility and metastasis. Taken together, it was indicated that secreted STC-1 promotes metastatic potential of breast cancer cells via activation of PI3K/AKT.

Human 45,X fibroblast transcriptome reveals distinct differentially expressed genes including long noncoding RNAs potentially associated with the pathophysiology of Turner syndrome

Turner syndrome is a chromosomal abnormality characterized by the absence of whole or part of the X chromosome in females. This X aneuploidy condition is associated with a diverse set of clinical phenotypes such as gonadal dysfunction, short stature, osteoporosis and Type II diabetes mellitus, among others. These phenotypes differ in their severity and penetrance among the affected individuals. Haploinsufficiency for a few X linked genes has been associated with some of these disease phenotypes. RNA sequencing can provide valuable insights to understand molecular mechanism of disease process. In the current study, we have analysed the transcriptome profiles of human untransformed 45,X and 46,XX fibroblast cells and identified differential expression of genes in these two karyotypes. Functional analysis revealed that these differentially expressing genes are associated with bone differentiation, glucose metabolism and gonadal development pathways. We also report differential expression of lincRNAs in X monosomic cells. Our observations provide a basis for evaluation of cellular and molecular mechanism(s) in the establishment of Turner syndrome phenotypes.

AKI after conditional and kidney-specific knockdown of stanniocalcin-1

Stanniocalcin-1 is an intracrine protein; it binds to the cell surface, is internalized to the mitochondria, and diminishes superoxide generation through induction of uncoupling proteins. In vitro, stanniocalcin-1 inhibits macrophages and preserves endothelial barrier function, and transgenic overexpression of stanniocalcin-1 in mice protects against ischemia-reperfusion kidney injury. We sought to determine the kidney phenotype after kidney endothelium-specific expression of stanniocalcin-1 small hairpin RNA (shRNA). We generated transgenic mice that express stanniocalcin-1 shRNA or scrambled shRNA upon removal of a floxed reporter (phosphoglycerate kinase-driven enhanced green fluorescent protein) and used ultrasound microbubbles to deliver tyrosine kinase receptor-2 promoter-driven Cre to the kidney to permit kidney endothelium-specific shRNA expression. Stanniocalcin-1 mRNA and protein were expressed throughout the kidney in wild-type mice. Delivery of tyrosine kinase receptor-2 promoter-driven Cre to stanniocalcin-1 shRNA transgenic kidneys diminished the expression of stanniocalcin-1 mRNA and protein throughout the kidneys. Stanniocalcin-1 mRNA and protein expression did not change in similarly treated scrambled shRNA transgenic kidneys, and we observed no Cre protein expression in cultured and tyrosine kinase receptor-2 promoter-driven Cre-transfected proximal tubule cells, suggesting that knockdown of stanniocalcin-1 in epithelial cells in vivo may result from stanniocalcin-1 shRNA transfer from endothelial cells to epithelial cells. Kidney-specific knockdown of stanniocalcin-1 led to severe proximal tubule injury characterized by vacuolization, decreased uncoupling of protein-2 expression, greater generation of superoxide, activation of the unfolded protein response, initiation of autophagy, cell apoptosis, and kidney failure. Our observations suggest that stanniocalcin-1 is critical for tubular epithelial survival under physiologic conditions.

Pregnancy prediction in single embryo transfer cycles after ICSI using QPCR: validation in oocytes from the same cohort

Cumulus cell (CC) gene expression is being explored as an additional method to morphological scoring to choose the embryo with the highest chance to pregnancy. In 47 ICSI patients with single embryo transfer (SET), from which individual CC samples had been stored, 12 genes using QPCR were retrospectively analyzed. The CC samples were at the same occasion also used to validate a previously obtained pregnancy prediction model comprising three genes (ephrin-B2 (EFNB2), calcium/calmodulin-dependent protein kinase ID, stanniocalcin 1). Latter validation yielded a correct pregnant/non-pregnant classification in 72% of the samples. Subsequently, 9 new genes were analyzed on the same samples and new prediction models were built. Out of the 12 genes analyzed a combination of the best predictive genes was obtained by stepwise multiple regression. One model retained EFNB2 in combination with glutathione S-transferase alpha 3 and 4, progesterone receptor and glutathione peroxidase 3, resulting in 93% correct predictions when 3 patient and treatment cycle characteristics were included into the model. This large patient group allowed to do an intra-patient analysis for 7 patients, an analysis mimicking the methodology that would ultimately be used in clinical routine. CC related to a SET that did not give pregnancy and CC related to their subsequent frozen/thawed embryos which ended in pregnancy were analyzed. The models obtained in the between-patient analysis were used to rank the oocytes within-patients for their chance to pregnancy and resulted in 86% of correct predictions. In conclusion, prediction models built on selected quantified transcripts in CC might help in the decision making process which is currently only based on subjective embryo morphology scoring. The validity of our current models for routine application still need prospective assessment in a larger and more diverse patient population allowing intra-patient analysis.

Stanniocalcin-1 in the subfornical organ inhibits the dipsogenic response to angiotensin II

Recently, receptors for the calcium-regulating glycoprotein hormone stanniocalcin-1 (STC-1) have been found within subfornical organ (SFO), a central structure involved in the regulation of electrolyte and body fluid homeostasis. However, whether SFO neurons produce STC-1 and how STC-1 may function in fluid homeostasis are not known. Two series of experiments were done in Sprague-Dawley rats to investigate whether STC-1 is expressed within SFO and whether it exerts an effect on water intake. In the first series, experiments were done to determine whether STC-1 was expressed within cells in SFO using immunohistochemistry, and whether protein and gene expression for STC-1 existed in SFO using Western blot and quantitative RT-PCR, respectively. Cells containing STC-1 immunoreactivity were found throughout the rostrocaudal extent of SFO. STC-1 protein expression within SFO was confirmed with Western blot, and SFO was also found to express STC-1 mRNA. In the second series, microinjections (200 nl) of STC-1, ANG II, a combination of the two or the vehicle were made into SFO in conscious, unrestrained rats. Water intake was measured at 0700 for a 1-h period after each injection in animals. Microinjections of STC-1 (17.6 or 176 nM) alone had no effect on water intake compared with controls. However, STC-1 not only attenuated the drinking responses to ANG II for about 30 min, but also decreased the total water intake over the 1-h period. These data suggest that STC-1 within the SFO may act in a paracrine/autocrine manner to modulate the neuronal responses to blood-borne ANG II. These findings also provide the first direct evidence of a physiological role for STC-1 in central regulation of body fluid homeostasis.

Overexpression of stanniocalcin-1 inhibits reactive oxygen species and renal ischemia/reperfusion injury in mice

Reactive oxygen species, endothelial dysfunction, inflammation, and mitogen-activated protein kinases have important roles in the pathogenesis of ischemia/reperfusion kidney injury. Stanniocalcin-1 (STC1) suppresses superoxide generation in many systems through induction of mitochondrial uncoupling proteins and blocks the cytokine-induced rise in endothelial permeability. Here we tested whether transgenic overexpression of STC1 protects from bilateral ischemia/reperfusion kidney injury. This injury in wild type mice caused a halving of the creatinine clearance; severe tubular vacuolization and cast formation; increased infiltration of macrophages and T cells; higher vascular permeability; greater production of superoxide and hydrogen peroxide; and higher ratio of activated ERK/activated JNK and p38, all compared to sham-treated controls. Mice transgenic for human STC1 expression, however, had resistance to equivalent ischemia/reperfusion injury indicated as no significant change from controls in any of these parameters. Tubular epithelial cells in transgenic mice expressed higher mitochondrial uncoupling protein 2 and lower superoxide generation. Pre-treatment of transgenic mice with paraquat, a generator of reactive oxygen species, before injury restored the susceptibility to ischemia/reperfusion kidney injury, suggesting that STC1 protects by an anti-oxidant mechanism. Thus, STC1 may be a therapeutic target for ischemia/reperfusion kidney injury.

Human stanniocalcin-1 suppresses angiotensin II-induced superoxide generation in cardiomyocytes through UCP3-mediated anti-oxidant pathway

Rationale

We have previously shown increased cardiac stanniocalcin-1 (STC1) in patients with idiopathic dilated cardiomyopathy. STC1 localizes to the inner mitochondrial membrane and transgenic over-expression of STC1 is associated with increased energy utilization.

Objective

We examined the hypothesis that STC1 uncouples mitochondrial oxidative phosphorylation - to suppress superoxide generation and modulate neurohormonal effects on cardiomyocytes.

Methods and Results

Compared to WT mouse heart, STC1 Tg heart displays: 2-fold higher uncoupling protein 3 (UCP3) levels, but no effect on UCP2 protein; 40% lower ATP levels; but similar activities of respiratory chain complexes I-IV. In cultured adult rat and freshly-isolated mouse cardiomyocytes, rSTC1 induces UCP3, but not UCP2. Treatment of cardiomyocytes with STC1 decreases mitochondrial membrane potential and suppresses baseline and angiotensin II (Ang II)-induced superoxide generation. Furthermore, baseline superoxide generation is higher in freshly-isolated adult UCP3^−/− mouse cardiomyocytes compared to WT, suggesting an important role for UCP3 in regulating cardiomyocyte ROS under physiologic conditions. Treatment of UCP3^−/− cardiomyocytes with rSTC1 failed to suppress superoxide generation, suggesting that the effects of STC1 on superoxide generation in cardiomyocytes are UCP3-dependent.

Conclusion

STC1 activates a novel anti-oxidant pathway in cardiac myocytes through induction of UCP3, and may play an important role in suppressing ROS in the heart under normal physiologic conditions and ameliorate the deleterious effects of Ang II-mediated cardiac injury. Importantly, our data point to a critical role for the mitochondria in regulating ROS generation in response to Ang II.

New candidate genes to predict pregnancy outcome in single embryo transfer cycles when using cumulus cell gene expression

OBJECTIVE

To relate the gene expression in cumulus cells surrounding an oocyte to the potential of the oocyte, as evaluated by the embryo morphology (days 3 and 5) and pregnancy obtained in single-embryo transfer cycles.

DESIGN

Retrospective analysis of individual human cumulus complexes using quantitative real-time polymerase chain reaction for 11 genes.

SETTING

University hospital IVF center.

PATIENT(S)

Thirty-three intracytoplasmic sperm injection patients, of which 16 were pregnant (4 biochemical and 12 live birth).

INTERVENTION(S)

Gene expression analysis in human cumulus complexes collected individually at pickup, allowing a correlation with the outcome of the corresponding oocyte. Multiparametric models were built for embryo morphology parameters and pregnancy prediction to find the most predictive genes.

MAIN OUTCOME MEASURE(S)

Gene expression profile of 99 cumulus complexes for 11 genes.

RESULT(S)

For embryo morphology prediction, TRPM7, ITPKA, STC2, CYP11A1, and HSD3B1 were often retained as informative. Models for pregnancy-biochemical or live birth-complemented or not with patient and cycle characteristics, always retained EFNB2 and CAMK1D together with STC1 or STC2. Positive and negative predictive values of the live birth models were >85%.

CONCLUSION(S)

EFNB2 and CAMK1D are promising genes that could help to choose the embryo to transfer with the highest chance of a pregnancy.

Evolution and roles of stanniocalcin

In fish, stanniocalcin-1 (STC1) is a key endocrine factor that acts on gill, intestine and kidney to regulate serum calcium and phosphate homeostasis. The recent identification and study of mammalian STCs (STC1 and STC2) revealed that the hormones are made in virtually all tissues and they act primarily as paracrine/autocrine factors to regulate various biological functions. Based on their ubiquitous expression patterns and generally undetectable levels in blood serum, it is unlikely that the mammalian STCs play important roles in serum Ca(2+)/P(i) homeostasis. However current evidences still support the local action of STCs in Ca(2+) and P(i) transport, probably via their action on Ca(2+)-channels and Na(+)/P(i) co-transporter. At present, information about the sequence, expression and distribution of the STC receptor(s) is lacking. However, recent emerging evidence hints the involvement of STC1 and STC2 in the sub-cellular functions of mitochondria and endoplasmic reticulum respectively, particularly responding to oxidative stress and unfolded protein response. With increasing evidence that demonstrates the local actions of STCs, the focus of the research has been moved to cellular inflammation and carcinogenesis. This review integrates the information available on STCs in fish and mammals, focusing mainly on their embryonic origin, tissue distribution, their potential regulatory mechanisms and the modes of action, and their physiological and pathophysiological functions, particularly in cancer biology.

Intraovarian thrombin and activated protein C signaling system regulates steroidogenesis during the periovulatory period

In addition to its role in blood coagulation, thrombin directly stimulates protease-activated receptors (PAR) or interacts with thrombomodulin (THBD) to activate membrane-bound protein C which stimulates PAR1 and PAR4 receptors to promote downstream pleiotropic effects. Our DNA microarray, RT-PCR, and immunostaining analyses demonstrated ovarian expression of THBD, activated protein C (APC) receptor [endothelial protein C receptor (EPCR)], as well as PAR1 and PAR4 receptors in mice. After treatment of gonadotropin-primed immature mice with an ovulatory dose of human chorionic gonadotropin (hCG) (a LH surrogate), major increases in the expression of THBD, EPCR, PAR1, and PAR4 were detected in granulosa and cumulus cells of preovulatory follicles. Immunoassay analyses demonstrated sustained increases in ovarian prothrombin and APC levels after hCG stimulation. We obtained luteinizing granulosa cells from mice treated sequentially with equine CG and hCG. Treatment of these cells with thrombin or agonists for PAR1 or PAR4 decreased basal and forskolin-induced cAMP biosynthesis and suppressed hCG-stimulated progesterone production. In cultured preovulatory follicles, treatment with hirudin (a thrombin antagonist) and SCH79797 (a PAR1 antagonist) augmented hCG-stimulated progesterone biosynthesis, suggesting a suppressive role of endogenous thrombin in steroidogenesis. Furthermore, intrabursal injection with hirudin or SCH79797 led to ipsilateral increases in ovarian progesterone content. Our findings demonstrated increased ovarian expression of key components of the thrombin-APC-PAR1/4 signaling system after LH/hCG stimulation, and this signaling pathway may allow optimal luteinization of preovulatory follicles. In addition to assessing the role of thrombin and associated genes in progesterone production by the periovulatory ovary, these findings provide a model with which to study molecular mechanisms underlying thrombin-APC-PAR1/4 signaling.

Up-regulation of stanniocalcin 1 expression by 1,25-dihydroxy vitamin D(3) and parathyroid hormone in renal proximal tubular cells

Stanniocalcin 1 and stanniocalcin 2 are two glycoprotein hormones, which act as calcium phosphate-regulating factor on intestine and kidney. We have previously reported that stanniocalcin 2 expression is positively and negatively controlled by 1,25(OH)₂D₃ and parathyroid hormone in renal proximal tubular cells. However, it has been unclear whether they regulate the stanniocalcin 1 gene expression. In this study, we identified the opossum stanniocalcin 1 cDNA sequence. The opossum stanniocalcin 1 amino acid sequence had 83% homology with human stanniocalcin 1, and has a conserved putative N-linked glycosylation site. Real-time PCR analysis using opossum kidney proximal tubular (OK-P) cells revealed that the mRNA levels of stanniocalcin 1 gene is up-regulated by both 1,25(OH)₂D₃ and parathyroid hormone in dose-dependent and time-dependent manners. We also demonstrated that the stanniocalcin 1 expression was increased in parathyroid hormone injected rat kidney. Furthermore, the mRNA expression of stanniocalcin 1 and stanniocalcin 2 were oppositely regulated by phorbol 12,13-myristic acetate, a specific PKC activator. Interestingly, the up-regulation of stanniocalcin 1 gene by 1,25(OH)₂D₃ and phorbol 12,13-myristic acetate were not prevented in the presence of actinomycin D, an RNA synthesis inhibitor. These results suggest that the stanniocalcin 1 gene expression is up-regulated by 1,25(OH)₂D₃ and parathyroid hormone through mRNA stabilization in renal proximal tubular cells.

Changes in gene expression associated with reproductive maturation in wild female baboons

Changes in gene expression during development play an important role in shaping morphological and behavioral differences, including between humans and nonhuman primates. Although many of the most striking developmental changes occur during early development, reproductive maturation represents another critical window in primate life history. However, this process is difficult to study at the molecular level in natural primate populations. Here, we took advantage of ovarian samples made available through an unusual episode of human-wildlife conflict to identify genes that are important in this process. Specifically, we used RNA sequencing (RNA-Seq) to compare genome-wide gene expression patterns in the ovarian tissue of juvenile and adult female baboons from Amboseli National Park, Kenya. We combined this information with prior evidence of selection occurring on two primate lineages (human and chimpanzee). We found that in cases in which genes were both differentially expressed over the course of ovarian maturation and also linked to lineage-specific selection this selective signature was much more likely to occur in regulatory regions than in coding regions. These results suggest that adaptive change in the development of the primate ovary may be largely driven at the mechanistic level by selection on gene regulation, potentially in relationship to the physiology or timing of female reproductive maturation.

Stanniocalcin 1 affects redox status of swine granulosa cells

Stanniocalcin 1 (STC1) is a glycoprotein hormone expressed in different mammalian tissues. In previous studies, we showed STC1 expression in swine ovarian follicles and we demonstrated that STC1 may be a physiological regulator of follicular function. Since reactive oxygen species (ROS) are important signal transducers in the ovary, the present study was undertaken to investigate STC1 action on ROS generation and on the activity of the major enzymatic and non-enzymatic scavengers in swine granulosa cells. O(2)- generation, catalase activity and FRAP levels were increased by STC1, whereas H(2)O(2) generation and peroxidase activity were decreased by STC1. Taken together, our data show that STC1 modulates redox status in swine granulosa cells.

Stanniocalcin has deep evolutionary roots in eukaryotes

Vertebrates have a large glycoprotein hormone, stanniocalcin, which originally was shown to inhibit calcium uptake from the environment in teleost fish gills. Later, humans, other mammals, and teleost fish were shown to have two forms of stanniocalcin (STC1 and STC2) that were widely distributed in many tissues. STC1 is associated with calcium and phosphate homeostasis and STC2 with phosphate, but their receptors and signaling pathways have not been elucidated. We undertook a phylogenetic investigation of stanniocalcin beyond the vertebrates using a combination of BLAST and HMMER homology searches in protein, genomic, and expressed sequence tag databases. We identified novel STC homologs in a diverse array of multicellular and unicellular organisms. Within the eukaryotes, almost all major taxonomic groups except plants and algae have STC homologs, although some groups like echinoderms and arthropods lack STC genes. The critical structural feature for recognition of stanniocalcins was the conserved pattern of ten cysteines, even though the amino acid sequence identity was low. Signal peptides in STC sequences suggest they are secreted from the cell of synthesis. The role of glycosylation signals and additional cysteines is not yet clear, although the 11th cysteine, if present, has been shown to form homodimers in some vertebrates. We predict that large secreted stanniocalcin homologs appeared in evolution as early as single-celled eukaryotes. Stanniocalcin's tertiary structure with five disulfide bonds and its primary structure with modest amino acid conservation currently lack an established receptor-signaling system, although we suggest possible alternatives.

Stanniocalcin 1 and ovarian tumorigenesis

BACKGROUND

Stanniocalcin 1 (STC1) is a secreted glycoprotein hormone. High expression of STC1 has been associated with several cancers including ovarian cancer, but its role in the development of ovarian cancer is not clear.

METHODS

We used five human ovarian epithelial cancer cell lines (OVCA420, OVCA432, OVCA433, SKOV3, and HEY), immortalized human ovarian surface epithelial cells (T29 and T80), ovarian cancer tissues from 342 patients, serum from 73 ovarian cancer patients and from58 control subjects, and 116 mice, with six or eight per group. Protein expression was assessed. Cells overexpressing STC1 protein were generated by ectopic expression of human STC1 cDNA. STC1 expression was silenced by using small interfering RNA against STC1. Cell proliferation, migration, colony formation, and apoptosis were assessed. Xenograft tumor growth in mice was studied. Neutralizing anti-STC1 antibody was used to inhibit STC1 function. All statistical tests were two-sided.

RESULTS

STC1 protein expression was higher in all human ovarian cancer cell lines examined than in immortalized human ovarian epithelial cell lines, higher in ovarian cancer tissue than in normal ovarian tissue (P < .001), and higher in serum from ovarian cancer patients than from control subjects (P = .021). Ovarian cancer cells with STC1 overexpression, compared with corresponding control cells, had increased cell proliferation, migration, and colony formation in cell culture and increased growth of xenograft tumors in mice. These activities in normal or malignant ovarian cells with STC1 overexpression, compared with control cells, were also accompanied by increased expression of cell cycle regulatory proteins and antiapoptotic proteins but decreased cleavage of several caspases. Within 24 hours of treatment, apoptosis in cultures of HEY ovarian cancer cells treated with neutralizing anti-STC1 monoclonal antibody was higher (17.3% apoptotic cells) than that in cultures treated with mouse IgG control cells (4.4%) (12.9% difference, 95% confidence interval = 11.6% to 14.2%).

CONCLUSIONS

STC1 protein may be involved in ovarian tumorigenesis.

Expression and localization of stanniocalcin 1 in swine ovary

Stanniocalcin 1 (STC 1) is a glycoprotein involved in mineral homeostasis and was first identified in fish. Its mammalian homologue has been implicated in the regulation of various biological processes, including angiogenesis and steroidogenesis both of which are fundamental events in ovarian function. Interestingly, the highest level of STC 1 expression in mammals occurs in ovarian tissue but no information is available on swine species. Therefore, the present study was undertaken to investigate the expression and the immunolocalization of STC 1 in swine ovary. In addition, we evaluated whether swine granulosa cells synthesize STC 1 and its possible modulation by hypoxia, a physiological condition in ovarian follicle growth. Our data show STC 1 for the first time in swine ovary; moreover, we demonstrate STC 1 production by granulosa cells, both in basal condition and in response to oxygen deprivation. The latter is suggestive of a potential modulatory role for STC 1 in hypoxia-driven angiogenesis.

Thyrostimulin, but not thyroid-stimulating hormone (TSH), acts as a paracrine regulator to activate the TSH receptor in mammalian ovary

The thyroid-stimulating hormone receptor (TSHR), activated by either TSH or the newly discovered glycoprotein hormone thyrostimulin, plays a central role in the control of body metabolism. Interestingly, in addition to its thyroid expression, we discovered that the mRNA level of TSHR is periodically regulated in rat ovary by gonadotropins. Ovarian microdissection followed by real-time PCR analysis indicated that granulosa cells show the highest level of TSHR expression. Cultures of follicles and primary granulosa cells demonstrated that the level of TSHR is up-regulated and decreased by the gonadotropin-driven cAMP cascade and estradiol production, respectively. Furthermore, in contrast to the negligible expression of TSH in the ovary, we also found by real-time PCR and immunohistochemical analysis that thyrostimulin is expressed mainly in oocytes. Evolving before the appearance of gonadotropins, thyrostimulin is considered the most ancestral glycoprotein hormone. Therefore, the presence of thyrostimulin in the ovary suggests that it may have a primitive function in reproduction when it activates ovarian TSHR. Next, we generated recombinant thyrostimulin protein and characterized its non-covalent heterodimeric nature. Using purified recombinant thyrostimulin, we show that the human ovarian cell line NIH:OVCAR-3 also expresses endogenous and functional TSHR. Using cultured rat granulosa cells isolated from different ovarian stages, we found that treatments with thyrostimulin significantly increase cAMP production and the c-fos gene response in the presence of gonadotropins. Thus, this study demonstrates that oocyte-derived thyrostimulin and granulosa cell-expressed TSHR compose a novel paracrine system in the ovary, where the activity is tightly controlled by gonadotropins.

cDNA cloning of Japanese flounder stanniocalcin 2 and its mRNA expression in a variety of tissues

Stanniocalcin 1 (STC1) is a glycoprotein hormone important in the maintenance of calcium and phosphate homeostasis in both fishes and mammals. Although two related STC genes, STC1 and STC2, were found to be expressed in multiple tissues as paracrine regulators in mammals, spatial expression pattern of stc2 mRNA has not been elucidated in fishes in contrast to that of clearly described stc1. In the present study, we have cloned and characterized a full-length stc2 cDNA from Japanese flounder (Paralichyhus olivaceus) ovary and analyzed expression pattern of stc2 in both sexes. The flounder stc2 cDNA (1501 nucleotides) encoded a putative prehormone of 286 amino acids (aa) with a signal peptide of 20 aa and a mature protein of 266 aa. The deduced aa sequence of flounder stc2 showed high sequence identity with those of pufferfish, zebrafish, and human (57.7-89.0%), whereas it showed less identity with that of flounder stc1 (24.3%). RT-PCR analysis revealed that the flounder stc2 gene is expressed in all examined tissues including the pituitary, brain, heart, kidney, gills, stomach, spleen, skin, dorsal fin, skeletal muscle, liver, corpuscles of Stannius, intestine, ovary and testis. Our data indicate that fish stc2 gene, like stc1, is expressed in a wide variety of tissues.

Effects of in vitro maturation on gene expression in rhesus monkey oocytes

In vitro oocyte maturation (IVM) holds great promise as a tool for enhancing clinical treatment of infertility, enhancing availability of nonhuman primates for development of disease models, and facilitating endangered species preservation. However, IVM outcomes have remained significantly below the success rates obtained with in vivo matured (VVM) oocytes from humans and nonhuman primates. A cDNA array-based analysis is presented, comparing the transcriptomes of VVM oocytes with IVM oocytes. We observe a small set of just 59 mRNAs that are differentially expressed between the two cell types. These mRNAs are related to cellular homeostasis, cell-cell interactions including growth factor and hormone stimulation and cell adhesion, and other functions such as mRNA stability and translation. Additionally, we observe in IVM oocytes overexpression of PLAGL1 and MEST, two maternally imprinted genes, indicating a possible interruption or loss of correct epigenetic programming. These results indicate that, under certain IVM conditions, oocytes that are molecularly highly similar to VVM oocytes can be obtained; however, the interruption of normal oocyte-somatic cell interactions during the final hours of oocyte maturation may preclude the establishment of full developmental competence.

Expression profiling of a high-fertility mouse line by microarray analysis and qPCR

Background

In a recent study it was demonstrated that a largely increased ovulation number is responsible for high prolificacy in two mouse lines selected for fertility performance. The objective of the present study was to identify genes that are involved in increasing the ovulation number in one of these lines, FL1. For differential expression profiling, ovaries of FL1 and of a non-selected control line, DUKsi, both lines derived from the same genetic pool, were analyzed with microarray analysis and quantitative polymerase chain reaction (qPCR). Ovaries from 30 animals of each line were collected at the metestrous stage, combined to 6 pools each, and processed for microarray analysis.

Results

The actual number of ova shed in FL1 exceeded that of the DUKsi control line more than twofold (26.6 vs. 12.9). 148 differentially expressed ovarian transcripts could be identified, 74 of them up- and 74 down-regulated. Of these, 47 significantly mapped to specific Gene Ontology (GO) terms representing different biological processes as steroid metabolism, folliculogenesis, immune response, intracellular signal transduction (particularly of the G protein signaling cascade), regulation of transcription and translation, cell cycle and others. qPCR was used to re-evaluate selected transcripts and to estimate inter-individual variation of expression levels. These data significantly correlated with microarray data in 12 out of 15 selected transcripts but revealed partly large variations of expression levels between individuals.

Conclusion

(1) The abundance of numerous ovarian transcripts was significantly different in FL1 compared to the non-selected control line DUKsi thus suggesting that at least some of the respective genes and corresponding biological processes are involved in improving reproductive traits, particularly by increasing the number of ovulation. (2) Selective qPCR re-evaluation largely confirmed the microarray data and in addition demonstrated that sample pooling can be beneficial to find out group-specific expression profiles despite of large inter-individual variation. (3) The present data will substantially help ongoing genetic association studies to identify candidate genes and causative mutations responsible for increased fertility performance in mice.