The role for runt related transcription factor 2 (RUNX2) as a transcriptional repressor in luteinizing granulosa cells

Progesterone receptor mediates ovulatory transcription through RUNX transcription factor interactions and chromatin remodelling

Progesterone receptor (PGR) plays diverse roles in reproductive tissues and thus coordinates mammalian fertility. In the ovary, rapid acute induction of PGR is the key determinant of ovulation through transcriptional control of a unique set of genes that culminates in follicle rupture. However, the molecular mechanisms for this specialized PGR function in ovulation is poorly understood. We have assembled a detailed genomic profile of PGR action through combined ATAC-seq, RNA-seq and ChIP-seq analysis in wildtype and isoform-specific PGR null mice. We demonstrate that stimulating ovulation rapidly reprograms chromatin accessibility in two-thirds of sites, correlating with altered gene expression. An ovary-specific PGR action involving interaction with RUNX transcription factors was observed with 70% of PGR-bound regions also bound by RUNX1. These transcriptional complexes direct PGR binding to proximal promoter regions. Additionally, direct PGR binding to the canonical NR3C motif enable chromatin accessibility. Together these PGR actions mediate induction of essential ovulatory genes. Our findings highlight a novel PGR transcriptional mechanism specific to ovulation, providing new targets for infertility treatments or new contraceptives that block ovulation.

A single-cell gene expression atlas of human follicular aspirates: Identification of leukocyte subpopulations and their paracrine factors

Leukocytes are in situ regulators critical for ovarian function. However, little is known about leukocyte subpopulations and their interaction with follicular cells in ovulatory follicles, especially in humans. Single-cell RNA sequencing (scRNA-seq) was performed using follicular aspirates obtained from four IVF patients and identified 13 cell groups: one granulosa cell group, one thecal cell group, 10 subsets of leukocytes, and one group of RBC/platelet. RNA velocity analyses on five granulosa cell populations predicted developmental dynamics denoting two projections of differentiation states. The cell type-specific transcriptomic profiling analyses revealed the presence of a diverse array of leukocyte-derived factors that can directly impact granulosa cell function by activating their receptors (e.g., cytokines and secretory ligands) and are involved in tissue remodeling (e.g., MMPs, ADAMs, ADAMTSs, and TIMPs) and angiogenesis (e.g., VEGFs, PGF, FGF, IGF, and THBS1) in ovulatory follicles. Consistent with the findings from the scRNA-seq data, the leukocyte-specific expression of CD68, IL1B, and MMP9 was verified in follicle tissues collected before and at defined hours after hCG administration from regularly cycling women. Collectively, this study demonstrates that this data can be used as an invaluable resource for identifying important leukocyte-derived factors that promote follicular cell function, thereby facilitating ovulation and luteinization in women.

Role of Runx2 in prostate development and stem cell function

BACKGROUND

RUNX2, a critical transcription factor in bone development, is also expressed in prostate and breast where it has been linked to cancer progression and cancer stem cells. However, its role in normal prostate biology has not been previously examined.

METHODS

Selective growth of murine prostate epithelium under non-adherent conditions was used to enrich for stem cells. Expression of runt domain transcription factors, stem cell and prostate marker messenger RNAs (mRNAs) was determined by quantitative reverse transcription polymerase chain reaction. Effects of Runx2 loss and gain-of-function on prostate epithelial cells were assessed using cells isolated from Runx2loxp/loxp mice transduced with Adeno-Cre or by Adeno-Runx2 transduction of wild type cells. Cellular distribution of RUNX2 and prostate-associated proteins was assessed using immunofluorescence microscopy. In vivo Runx2 knock out was achieved by tamoxifen treatment of Nkx3.1CreERT; Runx2loxp/loxp mice.

RESULTS

Prostate epithelium-derived spheroids, which are enriched in stem cells, were shown to contain elevated levels of Runx2 mRNA. Spheroid formation required Runx2 since adenovirus-Cre mediated knockout of Runx2 in prostatic epithelial cells from Runx2loxp/loxp mice severely reduced spheroid formation and stem cell markers while Runx2 overexpression was stimulatory. In vivo, Runx2 was detected during early prostate development (E16.5) and in adult mice where it was present in basal and luminal cells of ventral and anterior lobes. Prostate-selective deletion of Runx2 in tamoxifen-treated Nkx3.1CreERT; Runx2loxp/loxp mice severely inhibited growth and maturation of tubules in the anterior prostate and reduced expression of stem cell markers and prostate-associated genes.

CONCLUSION

This study demonstrates an important role for Runx2 in prostate development that may be explained by actions in prostate epithelial stem cells.

Gene analysis of major signaling pathways regulated by gonadotropins in human ovarian granulosa tumor cells (KGN)†

The female reproductive function largely depends on timing and coordination between follicle-stimulating hormone (FSH) and luteinizing hormone. Even though it was suggested that these hormones act on granulosa cells via shared signaling pathways, mainly protein kinases A, B, and C (PKA, PKB, and PKC), there is still very little information available on how these signaling pathways are regulated by each hormone to provide such differences in gene expression throughout folliculogenesis. To obtain a global picture of the principal upstream factors involved in PKA, PKB, and PKC signaling in granulosa cells, human granulosa-like tumor cells (KGN) were treated with FSH or specific activators (forskolin, SC79, and phorbol 12-myristate 13-acetate) for each pathway to analyze gene expression with RNA-seq technology. Normalization and cutoffs (FC 1.5, P ≤ 0.05) revealed 3864 differentially expressed genes between treatments. Analysis of major upstream regulators showed that PKA is a master kinase of early cell differentiation as its activation resulted in the gene expression profile that accompanies granulosa cell differentiation. Our data also revealed that the activation of PKC in granulosa cells is also a strong differentiation signal that could control "advanced" differentiation in granulosa cells and the inflammatory cascade that occurs in the dominant follicle. According to our results, PKB activation provides support for PKA-stimulated gene expression and is also involved in granulosa cell survival throughout follicular development. Taken together, our results provide new information on PKA, PKB, and PKC signaling pathways and their roles in stimulating a follicle at the crossroad between maturation/ovulation and atresia.

Core Binding Factors are essential for ovulation, luteinization, and female fertility in mice

Core Binding Factors (CBFs) are a small group of heterodimeric transcription factor complexes composed of DNA binding proteins, RUNXs, and a non-DNA binding protein, CBFB. The LH surge increases the expression of Runx1 and Runx2 in ovulatory follicles, while Cbfb is constitutively expressed. To investigate the physiological significance of CBFs, we generated a conditional mutant mouse model in which granulosa cell expression of Runx2 and Cbfb was deleted by the Esr2Cre. Female Cbfbflox/flox;Esr2cre/+;Runx2flox/flox mice were infertile; follicles developed to the preovulatory follicle stage but failed to ovulate. RNA-seq analysis of mutant mouse ovaries collected at 11 h post-hCG unveiled numerous CBFs-downstream genes that are associated with inflammation, matrix remodeling, wnt signaling, and steroid metabolism. Mutant mice also failed to develop corpora lutea, as evident by the lack of luteal marker gene expression, marked reduction of vascularization, and excessive apoptotic staining in unruptured poorly luteinized follicles, consistent with dramatic reduction of progesterone by 24 h after hCG administration. The present study provides in vivo evidence that CBFs act as essential transcriptional regulators of both ovulation and luteinization by regulating the expression of key genes that are involved in inflammation, matrix remodeling, cell differentiation, vascularization, and steroid metabolisms in mice.

Detection of insertions/deletions (InDels) within the goat Runx2 gene and their association with litter size and growth traits

Runt-related transcription factor 2 (Runx2) is characterized by its critical functions in osteoblastic and ovulatory processes. The goal of this study was to explore the insertion/deletion (indel) variants of this gene and to evaluate their association with productive traits. Herein, a 12 bp and 6 bp insertion within the Runx2 gene was uncovered in Shaanbei white cashmere goats (SBWC; n = 1200). Chi-square analysis revealed that the 12 bp insertion was related to litter size (p < 0.01). Further association analysis also found this insertion was significantly associated with litter size (p = 1.1E-5). Interestingly, this insertion was also significantly associated with chest circumference (p = 0.018). Additionally, the 6 bp insertion was associated with body length (p = 0.003), chest width (p = 0.011), and chest circumference (p = 0.005). Furthermore, diplotype associations also uncovered that the combined genotypes of these two indels also significantly affected litter size and growth traits (p < 0.05). These findings suggested that these two insertions within the Runx2 gene were significantly associated with reproduction and growth traits, which would make them beneficial functional DNA markers that can be used in goat breeding.

RUNX3 Promotes the Tumorigenic Phenotype in KGN, a Human Granulosa Cell Tumor-Derived Cell Line

Granulosa cell tumors of the ovary (GCT) are the predominant type of ovarian sex cord/stromal tumor. Although prognosis is generally favorable, the outcome for advanced and recurrent GCT is poor. A better understanding of the molecular pathogenesis of GCT is critical to developing effective therapeutic strategies. Here we have examined the potential role of the runt-related transcription factor RUNX3. There are only two GCT cell lines available. While RUNX3 is silenced in the GCT cell line KGN cells, it is highly expressed in another GCT cell line, COV434 cells. Re-expression of RUNX3 promotes proliferation, anchorage-independent growth, and motility in KGN cells in vitro and tumor formation in mice in vivo. Furthermore, expression of a dominant negative form of RUNX3 decreases proliferation of COV434 cells. To address a potential mechanism of action, we examined expression of cyclin D2 and the CDK inhibitor p27^Kip1, two cell cycle regulators known to be critical determinants of GCT cell proliferation. We found that RUNX3 upregulates the expression of cyclin D2 at the mRNA and protein level, and decreases the level of the p27^Kip1 protein, but not p27^Kip1 mRNA. In conclusion, we demonstrate that RUNX proteins are expressed in GCT cell lines and human GCT specimens, albeit at variable levels, and RUNX3 may play an oncogenic role in a subset of GCTs.

Ovulation: Parallels With Inflammatory Processes

The midcycle surge of LH sets in motion interconnected networks of signaling cascades to bring about rupture of the follicle and release of the oocyte during ovulation. Many mediators of these LH-induced signaling cascades are associated with inflammation, leading to the postulate that ovulation is similar to an inflammatory response. First responders to the LH surge are granulosa and theca cells, which produce steroids, prostaglandins, chemokines, and cytokines, which are also mediators of inflammatory processes. These mediators, in turn, activate both nonimmune ovarian cells as well as resident immune cells within the ovary; additional immune cells are also attracted to the ovary. Collectively, these cells regulate proteolytic pathways to reorganize the follicular stroma, disrupt the granulosa cell basal lamina, and facilitate invasion of vascular endothelial cells. LH-induced mediators initiate cumulus expansion and cumulus oocyte complex detachment, whereas the follicular apex undergoes extensive extracellular matrix remodeling and a loss of the surface epithelium. The remainder of the follicle undergoes rapid angiogenesis and functional differentiation of granulosa and theca cells. Ultimately, these functional and structural changes culminate in follicular rupture and oocyte release. Throughout the ovulatory process, the importance of inflammatory responses is highlighted by the commonalities and similarities between many of these events associated with ovulation and inflammation. However, ovulation includes processes that are distinct from inflammation, such as regulation of steroid action, oocyte maturation, and the eventual release of the oocyte. This review focuses on the commonalities between inflammatory responses and the process of ovulation.

Regulation and function of runt-related transcription factors (RUNX1 and RUNX2) in goat granulosa cells

Transcription factors, runt-related transcription factor 1 (RUNX1) and 2 (RUNX2), belong to the runt-related (RUNX) gene family and play critical roles in mammalian reproduction processes. However, the regulatory mechanisms of RUNX1 and RUNX2 expression or their functions in goat follicles remain largely unknown. Herein, RUNX1 and RUNX2 proteins were detected in the oocytes and granulosa cells of preantral and antral follicles, as well as corpus luteum by immunohistochemistry. Treatments with human chorionic gonadotropin (hCG) or with the agonists and inhibitors of hCG-induced intracellular signaling pathways in granulosa cells in vitro, we found that hCG increased RUNX1 expression by activating PKC and PI3K signaling molecules, and increased RUNX2 expression by activating adenylate cyclase, PKC, and PI3K signaling molecules. We also demonstrated that miR-181b expression is dependent on the hCG-induced activation of PKC and PKA, and miR-222 expression is dependent on the hCG-induced activation of PI3K and PKC in cultured granulosa cells. Meanwhile, miR-181b and miR-222 suppressed RUNX1 and RUNX2 expression by targeting RUNX1 and RUNX2 3' untranslated regions (3'UTRs) with or without hCG, respectively. These results suggested that hCG-mediated miR-181b and miR-222 expression are important for the regulation of RUNX1 and RUNX2 expression levels in granulosa cells. To explore the specific functions of RUNX1 and RUNX2, we transfected RUNX1 and RUNX2 small interfering RNAs into primary cultured granulosa cells. Knockdown of RUNX1 and RUNX2 significantly decreased progesterone productions and the mRNA abundance of key steroidogenic enzymes (StAR, CYP11A1 and HSD3B) after hCG treatment. But only miR-222 increased estradiol secretion in goat granulosa cells. In addition, knockdown of RUNX1 and RUNX2 also promoted granulosa cell proliferation. The hormonally regulated expression of RUNX1 and RUNX2 in granulosa cells, their involvement in progesterone production, and promoted granulosa cell proliferation suggest important roles of RUNX1 and RUNX2 in follicular development and luteinization.

Ablation of Runx2 in Ameloblasts Suppresses Enamel Maturation in Tooth Development

Runt-related transcription factor 2 (Runx2) is involved in the early stage of tooth development. However, only few studies have reported the role of Runx2 in enamel development, which may be attributed to that Runx2 full knockout mice cannot survive after birth. In the present study, we successfully established a Runx2-deficient mouse model using a conditional knockout (cKO) method. We observed a significant reduction in the degree of mineralization and the decreased size of enamel rods in cKO mice. Histological analysis showed the retained enamel proteins in enamel layer at maturation stage in cKO molars. Further analysis by qRT-PCR revealed that the expressions of genes encoding enamel structure proteins, such as amelogenin (AMELX), ameloblastin (AMBN) and enamelin (ENAM), were increased in cKO enamel organs. On the other hand, the expression of kallikrein-related peptidase-4 (KLK4) at the mRNA and protein levels was dramatically decreased from late secretory stage to maturation stage in cKO enamel organs, while the expression of matrix metalloproteinase-20 (MMP-20) was not significantly altered. Finally, immunohistochemistry indicated that the uptake of amelogenins by ameloblasts was significantly decreased in cKO mice. Taken together, Runx2 played critical roles in controlling enamel maturation by increasing synthesis of KLK4 and decreasing synthesis of AMELX, AMBN and ENAM.

Core Binding Factor β Expression in Ovarian Granulosa Cells Is Essential for Female Fertility

Core binding factor β (CBFβ) is a non-DNA-binding partner of all RUNX proteins and critical for transcription activity of CBF transcription factors (RUNXs/CBFβ). In the ovary, the expression of Runx1 and Runx2 is highly induced by the luteinizing hormone (LH) surge in ovulatory follicles, whereas Cbfb is constitutively expressed. To investigate the physiological significance of CBFs in the ovary, the current study generated two different conditional mutant mouse models in which granulosa cell expression of Cbfb and Runx2 was reduced by Cre recombinase driven by an Esr2 promoter. Cbfbgc-/- and Cbfbgc-/- × Runx2gc+/- mice exhibited severe subfertility and infertility, respectively. In the ovaries of both mutant mice, follicles develop normally, but the majority of preovulatory follicles failed to ovulate either in response to human chorionic gonadotropin administration in pregnant mare serum gonadotropin-primed immature animals or after the LH surge at 5 months of age. Morphological and physiological changes in the corpus luteum of these mutant mice revealed the reduced size, progesterone production, and vascularization, as well as excessive lipid accumulation. In granulosa cells of periovulatory follicles and corpora lutea of these mice, the expression of Edn2, Ptgs1, Lhcgr, Sfrp4, Wnt4, Ccrl2, Lipg, Saa3, and Ptgfr was also drastically reduced. In conclusion, the current study provided in vivo evidence that CBFβ plays an essential role in female fertility by acting as a critical cofactor of CBF transcription factor complexes, which regulate the expression of specific key ovulatory and luteal genes, thus coordinating the ovulatory process and luteal development/function in mice.

Vascular action of bisphosphonates: In vitro effect of alendronate on the regulation of cellular events involved in vessel pathogenesis

In this work we investigate whether, despite the procalcific action of alendronate on bone, the drug would be able to regulate in vitro the main cellular events that take part in atherosclerotic lesion generation. Using endothelial cell cultures we showed that Alendronate (1-50μM) acutely enhances nitric oxide production (10-30min). This stimulatory action of the bisphosphonate involves the participation of MAPK signaling transduction pathway. Under inflammatory stress, the drug reduces monocytes and platelets interactions with endothelial cells induced by lipopolysaccharide. Indeed the bisphophonate exhibits a significant inhibition of endothelial dependent platelet aggregation. The molecular mechanism of alendronate (ALN) on leukocyte adhesion depends on the regulation of the expression of cell adhesion related genes (VCAM-1; ICAM-1); meanwhile the antiplatelet activity is associated with the effect of the drug on nitric oxide production. On vascular smooth muscle cells, the drug exhibits ability to decrease osteogenic transdifferentiation and extracellular matrix mineralization. When vascular smooth muscle cells were cultured in osteogenic medium for 21days, they exhibited an upregulation of calcification markers (RUNX2 and TNAP), high alkaline phosphatase activity and a great amount of mineralization nodules. ALN treatment significantly down-regulates mRNA levels of osteoblasts markers; diminishes alkaline phosphatase activity and reduces the extracellular calcium deposition. The effect of ALN on vascular cells differs from its own bone action. On calvarial osteoblasts ALN induces cell proliferation, enhances alkaline phosphatase activity, and increases mineralization, but does not affect nitric oxide synthesis. Our results support the hypothesis that ALN is an active drug at vascular level that regulates key processes involved in vascular pathogenesis through a direct action on vessel cells.

Core Binding Factor-β Knockdown Alters Ovarian Gene Expression and Function in the Mouse

Core binding factor (CBF) is a heterodimeric transcription factor complex composed of a DNA-binding subunit, one of three runt-related transcription factor (RUNX) factors, and a non-DNA binding subunit, CBFβ. CBFβ is critical for DNA binding and stability of the CBF transcription factor complex. In the ovary, the LH surge increases the expression of Runx1 and Runx2 in periovulatory follicles, implicating a role for CBFs in the periovulatory process. The present study investigated the functional significance of CBFs (RUNX1/CBFβ and RUNX2/CBFβ) in the ovary by examining the ovarian phenotype of granulosa cell-specific CBFβ knockdown mice; CBFβ f/f * Cyp19 cre. The mutant female mice exhibited significant reductions in fertility, with smaller litter sizes, decreased progesterone during gestation, and fewer cumulus oocyte complexes collected after an induced superovulation. RNA sequencing and transcriptome assembly revealed altered expression of more than 200 mRNA transcripts in the granulosa cells of Cbfb knockdown mice after human chorionic gonadotropin stimulation in vitro. Among the affected transcripts are known regulators of ovulation and luteinization including Sfrp4, Sgk1, Lhcgr, Prlr, Wnt4, and Edn2 as well as many genes not yet characterized in the ovary. Cbfβ knockdown mice also exhibited decreased expression of key genes within the corpora lutea and morphological changes in the ovarian structure, including the presence of large antral follicles well into the luteal phase. Overall, these data suggest a role for CBFs as significant regulators of gene expression, ovulatory processes, and luteal development in the ovary.

Runx2 acts downstream of C/EBPβ to regulate the differentiation of uterine stromal cells in mice

Although Runx2 is involved in the regulation of cellular differentiation, its physiological roles in the differentiation of uterine stromal cells during decidualization still remain unknown. The aim of this study was to examine the expression, regulation and function of Runx2 in mouse uterus during decidualization. The results showed that Runx2 was highly expressed in the decidua and oil-induced decidualized cells. In the uterine stromal cells, recombinant human Runx2 (rRunx2) could induce the expression of Prl8a2 and Prl3c1 which are two well-known differentiation markers for decidualization, while inhibition of Runx2 with specific siRNA reduced their expression. Further study found that rRunx2 could improve the expression of Prl8a2 and Prl3c1 in the C/EBPβ siRNA-transfected stromal cells. In the stromal cells, cAMP analogue 8-Br-cAMP could induce the expression of Runx2. Moreover, the induction was blocked by PKA inhibitor H89. Simultaneously, attenuation of C/EBPβ with siRNA could also reduce the cAMP-induced Runx2 expression. Furthermore, siRNA-mediated silencing of Runx2 expression alleviated the effects of cAMP on the differentiation of stromal cells. Runx2 might act downstream of C/EBPβ to regulate the expression of Cox-2, Vegf and Mmp9 in the uterine stromal cells. Collectively, Runx2 may play an important role during mouse decidualization.

Gene expression of cumulus cells in women with poor ovarian response after dehydroepiandrosterone supplementation

OBJECTIVE

Our previous study showed the potential benefits of dehydroepiandrosterone (DHEA) supplementation in women with a poor ovarian response (POR). Because the connection between cumulus cells (CCs) and oocytes is a key step for oocyte maturation, we supposed that altered gene expression of CCs in women with POR after DHEA supplementation might favor oocyte maturation.

MATERIALS AND METHODS

Women with POR treated with flexible daily gonadotropin-releasing hormone antagonist in vitro fertilization (IVF) cycles at The Reproductive Center in Kaohsiung Veterans General Hospital, Kaohsiung, Taiwan between January 2013 and October 2013 were enrolled for this prospective study. CCs were isolated during IVF before and after DHEA (CPH-Formulation, Oakdale, CA, USA) supplementation. Nine genes of isolated CCs, including hyaluronan synthase (HAS2), versican (VCAN), thrombospondin 1 (THBS1), runt-related transcription factor 2 (RUNX2), chromobox homolog 3 (CBX3), tripartite motif-containing 28 (TRIM28), B-cell lymphoma 2 (BCL2), BCL2-associated X protein (BAX), and ankyrin repeat domain 57 (ANKRD57), were compared.

RESULTS

There was a significant difference in the expression of genes in women with POR before and after DHEA supplementation (all p < 0.05). All genes related to extracellular matrix (ECM) formation, including HAS2, VCAN, and THBS1, were upregulated. By contrast, all genes involving cell development, differentiation, and apoptosis regulation were downregulated. Unknown function gene ANKRD57 was also downregulated after DHEA supplementation. Although expressions of both BCL2 and BAX were decreased in women with POR after DHEA supplementation compared to those before treatment, the ratio of BCL2 and BAX was significantly increased in women with POR after DHEA supplementation, suggesting that DHEA supplementation might activate the antiapoptosis process of CCs, which might be beneficial to the improvement of ovarian function in women with POR.

CONCLUSION

The study showed that DHEA therapy positively affected the gene expression of CCs in women with POR, and provided evidence to support the positive effect of DHEA supplementation on women with POR.

Characterization of the Runx gene family in a jawless vertebrate, the Japanese lamprey (Lethenteron japonicum)

The cyclostomes (jawless vertebrates), comprising lampreys and hagfishes, are the sister group of jawed vertebrates (gnathostomes) and are hence an important group for the study of vertebrate evolution. In mammals, three Runx genes, Runx1, Runx2 and Runx3, encode transcription factors that are essential for cell proliferation and differentiation in major developmental pathways such as haematopoiesis, skeletogenesis and neurogenesis and are frequently associated with diseases. We describe here the characterization of Runx gene family members from a cyclostome, the Japanese lamprey (Lethenteron japonicum). The Japanese lamprey contains three Runx genes, RunxA, RunxB, and RunxC. However, phylogenetic and synteny analyses suggest that they are not one-to-one orthologs of gnathostome Runx1, Runx2 and Runx3. The major protein domains and motifs found in gnathostome Runx proteins are highly conserved in the lamprey Runx proteins. Although all gnathostome Runx genes each contain two alternative promoters, P1 (distal) and P2 (proximal), only lamprey RunxB possesses the alternative promoters; lamprey RunxA and RunxC contain only P2 and P1 promoter, respectively. Furthermore, the three lamprey Runx genes give rise to fewer alternative isoforms than the three gnathostome Runx genes. The promoters of the lamprey Runx genes lack the tandem Runx-binding motifs that are highly conserved among the P1 promoters of gnathostome Runx1, Runx2 and Runx3 genes; instead these promoters contain dispersed single Runx-binding motifs. The 3'UTR of lamprey RunxB contains binding sites for miR-27 and miR-130b/301ab, which are conserved in mammalian Runx1 and Runx3, respectively. Overall, the Runx genes in lamprey seem to have experienced a different evolutionary trajectory from that of gnathostome Runx genes which are highly conserved all the way from cartilaginous fishes to mammals.

Runx family genes in a cartilaginous fish, the elephant shark (Callorhinchus milii)

The Runx family genes encode transcription factors that play key roles in hematopoiesis, skeletogenesis and neurogenesis and are often implicated in diseases. We describe here the cloning and characterization of Runx1, Runx2, Runx3 and Runxb genes in the elephant shark (Callorhinchus milii), a member of Chondrichthyes, the oldest living group of jawed vertebrates. Through the use of alternative promoters and/or alternative splicing, each of the elephant shark Runx genes expresses multiple isoforms similar to their orthologs in human and other bony vertebrates. The expression profiles of elephant shark Runx genes are similar to those of mammalian Runx genes. The syntenic blocks of genes at the elephant shark Runx gene loci are highly conserved in human, but represented by shorter conserved blocks in zebrafish indicating a higher degree of rearrangements in this teleost fish. Analysis of promoter regions revealed conservation of binding sites for transcription factors, including two tandem binding sites for Runx that are totally conserved in the distal promoter regions of elephant shark Runx1-3. Several conserved noncoding elements (CNEs), which are putative cis-regulatory elements, and miRNA binding sites were identified in the elephant shark and human Runx gene loci. Some of these CNEs and miRNA binding sites are absent in teleost fishes such as zebrafish and fugu. In summary, our analysis reveals that the genomic organization and expression profiles of Runx genes were already complex in the common ancestor of jawed vertebrates.

Expression of mesenchymal stem cells-related genes and plasticity of aspirated follicular cells obtained from infertile women

After removal of oocytes for in vitro fertilization, follicular aspirates which are rich in somatic follicular cells are discarded in daily medical practice. However, there is some evidence that less differentiated cells with stem cell characteristics are present among aspirated follicular cells (AFCs). The aim of this study was to culture AFCs in vitro and to analyze their gene expression profile. Using the RT² Profiler PCR array, we investigated the expression profile of 84 genes related to stemness, mesenchymal stem cells (MCSs), and cell differentiation in AFCs enriched by hypoosmotic protocol from follicular aspirates of infertile women involved in assisted reproduction programme in comparison with bone marrow-derived mesenchymal stem cells (BM-MSCs) and fibroblasts. Altogether the expression of 57 genes was detected in AFCs: 16 genes (OCT4, CD49f, CD106, CD146, CD45, CD54, IL10, IL1B, TNF, VEGF, VWF, HDAC1, MITF, RUNX2, PPARG, and PCAF) were upregulated and 20 genes (FGF2, CASP3, CD105, CD13, CD340, CD73, CD90, KDR, PDGFRB, BDNF, COL1A1, IL6, MMP2, NES, NUDT6, BMP6, SMURF2, BMP4, GDF5, and JAG1) were downregulated in AFCs when compared with BM-MSCs. The genes which were upregulated in AFCs were mostly related to MSCs and connected with ovarian function, and differed from those in fibroblasts. The cultured AFCs with predominating granulosa cells were successfully in vitro differentiated into adipogenic-, osteogenic-, and pancreatic-like cells. The upregulation of some MSC-specific genes and in vitro differentiation into other types of cells indicated a subpopulation of AFCs with specific stemness, which was not similar to those of BM-MSCs or fibroblasts.

Plasticity of granulosa cells: on the crossroad of stemness and transdifferentiation potential

The ovarian follicle represents the basic functional unit of the ovary and consists of an oocyte, which is surrounded by granulosa cells (GCs). GCs play an important role in the growth and development of the follicle. They are subject to increased attention since it has recently been shown that the subpopulation of GCs within the growing follicle possesses exceptionally plasticity showing stem cell characteristics. In assisted reproduction programs, oocytes are retrieved from patients together with GCs, which are currently discarded daily, but could be an interesting subject to be researched and potentially used in regenerative medicine in the future. Isolated GCs expressed stem cell markers such as OCT-4, NANOG and SOX-2, showed high telomerase activity, and were in vitro differentiated into other cell types, otherwise not present within ovarian follicles. Recently another phenomenon demonstrated in GCs is transdifferentiation, which could explain many ovarian pathological conditions. Possible applications in regenerative medicine are also given.

Detection of RUNX2 gene expression in cumulus cells in women undergoing controlled ovarian stimulation

BACKGROUND

RUNX2 is a transcription factor, whose expression has been recently identified in the mouse ovary. Regulation of RUNX2 expression and its function in the human ovary have not been determined yet. The aim of the present study is the investigation of the possible correlation between RUNX2 gene expression in cumulus cells and controlled ovarian stimulation and pregnancy outcomes after ART treatment.

METHODS

A total of 41 patients undergoing ICSI treatment for male factor infertility were enrolled into a specific ART program, during which cumulus cells were collected. The expression of RUNX2 gene in cumulus cells was examined by real-time PCR.

RESULTS

Concerning RUNX2 gene expression, 12 out of 41 women were detected with RUNX2 expression, with ratios ranging from 0.84 to 1.00, while 28 out of 41 women had no expression (ratio = 0). Only 1 woman presented a weak RUNX2 gene expression (ratio = 0.52). From 8 women that proceeded to pregnancy, 7 of them did not express RUNX2 gene in cumulus cells, while one was the woman with weak gene expression that also achieved pregnancy. The group of women without RUNX2 expression presented higher number of follicles (p = 0.013), higher number of retrieved oocytes (p = 0.016), higher basal LH serum levels (p = 0.016) and higher peak estradiol levels (p = 0.013), while the number of fertilized oocytes differed marginally between the two groups (p = 0.089). Moreover, RUNX2 expression was negatively associated with LH levels (OR = 0.22, p = 0.021) and E2 levels (OR = 0.25, p = 0.026).

CONCLUSIONS

Consequently, based on the preliminary findings of the present pilot study a potential inhibitory mechanism of RUNX2 gene is observed in the ovary when high mRNA levels are detected, suggesting that RUNX2 could possibly be used as a candidate genetic marker in the monitoring of the outcome of an ART treatment.