GATA-4 is a granulosa cell factor employed in inhibin-alpha activation by the TGF-beta pathway

Unveiling the Ovarian Cell Characteristics and Molecular Mechanism of Prolificacy in Goats via Single-Nucleus Transcriptomics Data Analysis

Increases in litter size, which are influenced by ovulation, are responsible for between 74% and 96% of the economic value of genetic progress, which influences selection. For the selection and breeding of highly prolific goats, genetic mechanisms underlying variations in litter size should be elucidated. Here, we used single-nucleus RNA sequencing to analyze 44,605 single nuclei from the ovaries of polytocous and monotocous goats during the follicular phase. Utilizing known reference marker genes, we identified 10 ovarian cell types characterized by distinct gene expression profiles, transcription factor networks, and reciprocal interaction signatures. An in-depth analysis of the granulosa cells revealed three subtypes exhibiting distinct gene expression patterns and dynamic regulatory mechanisms. Further investigation of cell-type-specific prolificacy-associated transcriptional changes elucidated that "downregulation of apoptosis", "increased anabolism", and "upstream responsiveness to hormonal stimulation" are associated with prolificacy. This study provides a comprehensive understanding of the cell-type-specific mechanisms and regulatory networks in the goat ovary, providing insights into the molecular mechanisms underlying goat prolificacy. These findings establish a vital foundation for furthering understanding of the molecular mechanisms governing folliculogenesis and for improving the litter size in goats via molecular design breeding.

Ovarian follicle transcriptome dynamics reveals enrichment of immune system process during transition from small to large follicles in cyclic Indian Ghoongroo pigs

Ovarian follicular development is a critical determinant of reproductive performance in litter bearing species like pigs, wherein economic gains depend on litter size. The study aimed to gain insight into the differentially expressed genes (DEGs) and signalling pathways regulating follicular growth and maturation in Ghoongroo pigs. Transcriptome profiling of porcine small follicles (SF) and large follicles (LF) was conducted using NovaSeq600 sequencing platform and DEGs were identified using DESeq2 with threshold of Padj. < 0.05 and log2 fold change cut off 0.58 (LF vs. SF). Functional annotations and bioinformatics analysis of DEGs were performed to find out biological functions, signalling pathways and hub genes regulating follicular dynamics. Transcriptome analysis revealed 709 and 479 genes unique to SF and LF stages, respectively, and 11,993 co-expressed genes in both the groups. In total, 507 DEGs (284 upregulated and 223 downregulated) were identified, which encoded for diverse proteins including transcription factors (TFs). These DEGs were functionally linked to response to stimulus, lipid metabolic process, developmental process, extracellular matrix organisation along with the immune system process, indicating wide-ranging mechanisms associated with follicular transition. The enriched KEGG pathways in LF stage consisted of ovarian steroidogenesis, cholesterol and retinol metabolism, cell adhesion molecules, cytokine receptor interaction and immune signalling pathways, depicting intra-follicular control of varied ovarian function. The hub gene analysis revealed APOE, SCARB1, MMP9, CYP17A1, TYROBP as key regulators of follicular development. This study identified candidate genes and TFs providing steroidogenic advantage to LFs which makes them fit for selection into the ovulatory pool of follicles.

Immunohistochemical markers of prognosis in adult granulosa cell tumors of the ovary - a review

BACKGROUND

Granulosa cell tumors (GCT) are rare malignant ovarian tumors. The two subtypes, adult and juvenile granulosa cell tumors, differ in clinical and molecular characteristics. GCT are low-malignant tumors and are generally associated with favorable prognosis. However, relapses are common even years and decades after diagnosis. Prognostic and predictive factors are difficult to assess in this rare tumor entity. The purpose of this review is to provide a comprehensive overview of the current state of knowledge on prognostic markers of GCT to identify patients with a high risk of recurrence.

METHODS

Systematic research for adult ovarian granulosa cell tumors and prognosis revealed n = 409 English full text results from 1965 to 2021. Of these articles, n = 35 were considered for this review after title and abstract screening and topic-specific matching. A specific search for pathologic markers with prognostic relevance for GCT identified n = 19 articles that were added to this review.

RESULTS

FOXL2 mutation and FOXL2 mRNA were inverse and immunohistochemical (IHC) expression of CD56, GATA-4 and SMAD3 was associated with reduced prognosis. IHC analysis of estrogen receptor, Anti-Mullerian hormone (AMH) and inhibin was not associated with prognosis for GCT. Analyses of mitotic rate, Ki-67, p53, β-catenin and HER2 revealed inconsistent results.

Incidental FOXL2 mutated adult granulosa cell tumour of the ovary with thecoma-like foci

We report on the incidental finding of a FOXL2 mutated adult granulosa cell tumour of the ovary with thecoma-like foci, a rare entity recently described by Jennifer N. Stall and Robert H. Young in a series of sixteen cases in 2019, displaying features differing from conventional adult granulosa cell tumour. Our aim is to specify the morphologic and molecular particularities of this presumably underrecognized finding, with a short presentation of the typical clinical context. Awareness of this rare and challenging neoplasm with indeterminate clinical course is crucial in routine diagnostics.

Transcript abundance of anti-Mullérian hormone and follicle-stimulating hormone receptor predicted superstimulatory response in embryo donor Holstein cows

The goal was to investigate the relationship among mRNA expressions of anti-Mullérian hormone (AMH), follicle-stimulating hormone receptor (FSHR) and responses to superovulation (SO) in embryo donor dairy cows. Holstein cows (n = 19) were submitted to a standard SO protocol, with twice daily FSH treatments, and artificially inseminated. Prior to SO (Day 0), relative mRNA expressions of AMH and FSHR in blood were determined for all cows. Day 7 embryos were collected and were graded to determine superovulatory response for each donor. Results showed that relative mRNA expressions of AMH and FSHR were positively correlated (R²  = 0.94). Relative mRNA expressions of both AMH and FSHR were positively correlated with total embryos (R²  = 0.68 and 0.69, respectively), total transferable embryos (R²  = 0.92 and 0.97, respectively) and total grade 1 embryos (R²  = 0.54 and 0.59, respectively). Further, transcript abundances of AMH and FSHR positively associated with milk production of donor cows, and meanwhile, they were negatively associated with days in milk (DIM) at submission of cows to SO (p < .05) protocol. The relative mRNA expression of AMH was higher (p < .05) in donor cows <5 years of age. However, age of donor at superovulation did not influence mRNA expression of FSHR. Collectively, we infer that the mRNA expressions of AMH and FSHR prior to superovulation can predict donor cows' positive response to superovulation.

Granulosa Cell Tumors: Novel Predictors of Recurrence in Early-stage Patients

Granulosa cell tumors (GCTs) comprise 2% to 5% of ovarian neoplasms, with unpredictable patterns of recurrence. The HER family, GATA4, and SMAD3 genes are reportedly involved in GCT proliferation and apoptosis and may serve as new predictors of recurrence. The aim of the study was to evaluate novel predictors of recurrence in GCT from a large single institution cohort. Patients diagnosed with GCTs (n=125) between 1975 and 2014 were identified. Clinicopathologic parameters were obtained and immunohistochemical evaluation was performed of calretinin, inhibin, HER2, CD56, SMAD3, and GATA4. Statistical analyses were conducted using Fisher exact test and Kaplan-Meier survival curves and Cox regression analysis. The median follow-up period was 120 months (range, 1-465 mo). Recurrence was noted in 12/125 (9.6%) patients. Kaplan-Meier analysis showed a shorter mean disease-free interval in whites versus blacks (P=0.001), stage III-IV versus stage I-II (P=0.0001), patients treated with surgery+chemotherapy versus surgery (P=0.0001), mitotic rate ≥4 (P=0.005), severe nuclear pleomorphism (P=0.013), high HER2 expression (P=0.001), high CD56 expression (P=0.001), and high SMAD3 expression (P=0.001). On Cox regression analysis, SMAD3 and type of treatment received were the only 2 independent prognostic factors for disease-free interval (P=0.03 and P=0.007, respectively). On subanalysis for early-stage (stage I) GCTs, the need for adjuvant chemotherapy and high expression of SMAD3 continued to be independent predictors of recurrence (HR=10.2, P=0.01 and HR=8.9, P=0.001, respectively).

GATA4 is a transcriptional regulator of R-spondin1 in Japanese flounder (Paralichthys olivaceus)

GATA4 is a well-known transcription factor of the GATA family implicated in regulation of sex determination and gonadal development in mammals. In this study, we cloned the full-length cDNA of Paralichthys olivaceus gata4 (Po-gata4). Phylogenetic, gene structure, and synteny analysis showed that Po-GATA4 is homologous to GATA4 of teleost and tetrapod. Po-gata4 transcripts were detected in Sertoli cells, spermatogonia, oogonia and oocytes, with higher transcript levels overall in the testis than the ovary. The promoter region of P. olivaceus R-spondin1was found to contain a GATA4-binding motif. Results of CBA (cleaved amplified polymorphic sequence-based binding assay) indicated that GATA4 could indeed bind to the promoter sequence of R-spondin1. Moreover, human GATA4 recombinant protein could upregulate R-spondin1 in P. olivaceus ovary cells and FBCs (flounder brain cell line). In FBCs, overexpression of Po-gata4 resulted in elevated transcript levels of R-spondin1. Taken together, our results indicate that Po-GATA4 is involved in gonadal development by regulating R-spondin1 expression.

GATA Regulation and Function During the Ovarian Life Cycle

GATA4 and GATA6 are the sole GATA factors expressed in the ovary during embryonic development and adulthood. Up today, GATA4 and GATA6 are the only transcription factors that have been conditionally deleted during ovarian development and at each major stage of follicle maturation. The evidence from these transgenic mice revealed that GATA4 and GATA6 are crucial for follicles assembly, granulosa cell differentiation, postnatal follicle growth, and luteinization. Thus, conditional knockdown of both factors in the granulosa cells at any stage of development leads to female infertility. GATA targets impacting female reproduction include genes involved in steroidogenesis, hormone signaling, ovarian hormones, extracellular matrix organization, and apoptosis/cell division.

Pathogenesis and treatment of adult-type granulosa cell tumor of the ovary

Adult-type granulosa cell tumor is a clinically and molecularly unique subtype of ovarian cancer. These tumors originate from the sex cord stromal cells of the ovary and represent 3-5% of all ovarian cancers. The majority of adult-type granulosa cell tumors are diagnosed at an early stage with an indolent prognosis. Surgery is the cornerstone for the treatment of both primary and relapsed tumor, while chemotherapy is applied only for advanced or non-resectable cases. Tumor stage is the only factor consistently associated with prognosis. However, every third of the patients relapse, typically in 4-7 years from diagnosis, leading to death in 50% of these patients. Anti-Müllerian Hormone and inhibin B are currently the most accurate circulating biomarkers. Adult-type granulosa cell tumors are molecularly characterized by a pathognomonic somatic missense point mutation 402C->G (C134W) in the transcription factor FOXL2. The FOXL2 402C->G mutation leads to increased proliferation and survival of granulosa cells, and promotes hormonal changes. Histological diagnosis of adult-type granulosa cell tumor is challenging, therefore testing for the FOXL2 mutation is crucial for differential diagnosis. Large international collaborations utilizing molecularly defined cohorts are essential to improve and validate new treatment strategies for patients with high-risk or relapsed adult-type granulosa cell tumor. Key Messages: Adult-type granulosa cell tumor is a unique ovarian cancer with an indolent, albeit unpredictable disease course. Adult-type granulosa cell tumors harbor a pathognomonic somatic missense mutation in transcription factor FOXL2. The key challenges in the treatment of patients with adult-type granulosa cell tumor lie in the identification and management of patients with high-risk or relapsed disease.

Review on crosstalk and common mechanisms of endocrine disruptors: Scaffolding to improve PBPK/PD model of EDC mixture

Endocrine disruptor compounds (EDCs) are environment chemicals that cause harmful effects through multiple mechanisms, interfering with hormone system resulting in alteration of homeostasis, reproduction and developmental effect. Many of these EDCs have concurrent exposure with crosstalk and common mechanisms which may lead to dynamic interactions. To carry out risk assessment of EDCs' mixture, it is important to know the detailed toxic pathway, crosstalk of receptor and other factors like critical window of exposure. In this review, we summarize the major mechanism of actions of EDCs with the different/same target organs interfering with the same/different class of hormone by altering their synthesis, metabolism, binding and cellular action. To show the impact of EDCs on life stage development, a case study on female fertility affecting germ cell is illustrated. Based on this summarized discussion, major groups of EDCs are classified based on their target organ, mode of action and potential risk. Finally, a conceptual model of pharmacodynamic interaction is proposed to integrate the crosstalk and common mechanisms that modulate estrogen into the predictive mixture dosimetry model with dynamic interaction of mixture. This review will provide new insight for EDCs' risk assessment and can be used to develop next generation PBPK/PD models for EDCs' mixture analysis.

GATA factors in endocrine neoplasia

GATA transcription factors are structurally-related zinc finger proteins that recognize the consensus DNA sequence WGATAA (the GATA motif), an essential cis-acting element in the promoters and enhancers of many genes. These transcription factors regulate cell fate specification and differentiation in a wide array of tissues. As demonstrated by genetic analyses of mice and humans, GATA factors play pivotal roles in the development, homeostasis, and function of several endocrine organs including the adrenal cortex, ovary, pancreas, parathyroid, pituitary, and testis. Additionally, GATA factors have been shown to be mutated, overexpressed, or underexpressed in a variety of endocrine tumors (e.g., adrenocortical neoplasms, parathyroid tumors, pituitary adenomas, and sex cord stromal tumors). Emerging evidence suggests that GATA factors play a direct role in the initiation, proliferation, or propagation of certain endocrine tumors via modulation of key developmental signaling pathways implicated in oncogenesis, such as the WNT/β-catenin and TGFβ pathways. Altered expression or function of GATA factors can also affect the metabolism, ploidy, and invasiveness of tumor cells. This article provides an overview of the role of GATA factors in endocrine neoplasms. Relevant animal models are highlighted.

GATA4 and GATA6 Knockdown During Luteinization Inhibits Progesterone Production and Gonadotropin Responsiveness in the Corpus Luteum of Female Mice

The surge of luteinizing hormone triggers the genomic reprogramming, cell differentiation, and tissue remodeling of the ovulated follicle, leading to the formation of the corpus luteum. During this process, called luteinization, follicular granulosa cells begin expressing a new set of genes that allow the resulting luteal cells to survive in a vastly different hormonal environment and to produce the extremely high amounts of progesterone (P4) needed to sustain pregnancy. To better understand the molecular mechanisms involved in the regulation of luteal P4 production in vivo, the transcription factors GATA4 and GATA6 were knocked down in the corpus luteum by crossing mice carrying Gata4 and Gata6 floxed genes with mice carrying Cre recombinase fused to the progesterone receptor. This receptor is expressed exclusively in granulosa cells after the luteinizing hormone surge, leading to recombination of floxed genes during follicle luteinization. The findings demonstrated that GATA4 and GATA6 are essential for female fertility, whereas targeting either factor alone causes subfertility. When compared to control mice, serum P4 levels and luteal expression of key steroidogenic genes were significantly lower in conditional knockdown mice. The results also showed that GATA4 and GATA6 are required for the expression of the receptors for prolactin and luteinizing hormone, the main luteotropic hormones in mice. The findings demonstrate that GATA4 and GATA6 are crucial regulators of luteal steroidogenesis and are required for the normal response of luteal cells to luteotropins.

GATA4 is essential for bone mineralization via ERα and TGFβ/BMP pathways

Osteoporosis is a disease characterized by low bone mass, leading to an increased risk of fragility fractures. GATA4 is a zinc-finger transcription factor that is important in several tissues, such as the heart and intestines, and has recently been shown to be a pioneer factor for estrogen receptor alpha (ERα) in osteoblast-like cells. Herein, we demonstrate that GATA4 is necessary for estrogen-mediated transcription and estrogen-independent mineralization in vitro. In vivo deletion of GATA4, driven by Cre-recombinase in osteoblasts, results in perinatal lethality, decreased trabecular bone properties, and abnormal bone development. Microarray analysis revealed GATA4 suppression of TGFβ signaling, necessary for osteoblast progenitor maintenance, and concomitant activation of BMP signaling, necessary for mineralization. Indeed, pSMAD1/5/8 signaling, downstream of BMP signaling, is decreased in the trabecular region of conditional knockout femurs, and pSMAD2/3, downstream of TGFβ signaling, is increased in the same region. Together, these experiments demonstrate the necessity of GATA4 in osteoblasts. Understanding the role of GATA4 to regulate the tissue specificity of estrogen-mediated osteoblast gene regulation and estrogen-independent bone differentiation may help to develop therapies for postmenopausal osteoporosis.

Inhibin alpha gene expression in human trophoblasts is regulated by interactions between TFAP2 and cAMP signaling pathways

Inhibin α (Inha) gene expression is regulated, in rat granulosa cells, via a cyclic 3',5'-adenosine monophosphate (AMP)-response element (CRE) found in a region of the promoter that is homologous to the human INHA promoter. We previously found that during in vitro cytotrophoblast differentiation, human INHA gene expression was regulated by TFAP2A via association with an AP-2 site located upstream of this CRE. The aim of this study was to evaluate if the human INHA gene was also regulated by cAMP in trophoblasts, and to investigate the possible crosstalk between TFAP2 and cAMP signaling pathways in the regulation of INHA gene expression. Treatment with cAMP or forskolin increased INHA mRNA expression by 7- and 2-fold in primary cytotrophoblasts and choriocarcinoma-derived BeWo cells, respectively. Treatment with the protein kinase A inhibitor H-89 reduced forskolin-induced luciferase activity by ∼40% in BeWo cells transfected with an INHA promoter-driven luciferase reporter vector. TFAP2 overexpression increased basal luciferase activity, whereas the dominant repressor KCREB abolished it. Surprisingly, mutation of the CRE also eliminated the TFAP2-induced transcription, although TFAP2 overexpression was still able to increase forskolin-induced luciferase activity when the AP-2 binding site, but not the CRE site, was mutated. Thus, INHA gene expression is upregulated by cAMP via CRE in human trophoblasts, and TFAP2 regulates this expression by interacting with CRE.

GATA binding protein 2 mediates leptin inhibition of PPARγ1 expression in hepatic stellate cells and contributes to hepatic stellate cell activation

Hepatic stellate cell (HSC) activation is a crucial step in the development of liver fibrosis. Peroxisome-proliferator activated receptor γ (PPARγ) exerts a key role in the inhibition of HSC activation. Leptin reduces PPARγ expression in HSCs and plays a unique role in promoting liver fibrosis. The present studies aimed to investigate the mechanisms underlying leptin regulation of PPARγ1 (a major subtype of PPARγ) in HSCs in vivo and in vitro. Results revealed a leptin response region in mouse PPARγ1 promoter and indicated that the region included a GATA binding protein binding site around position -2323. GATA binding protein-2 (GATA-2) could bind to the site and inhibit PPARγ1 promoter activity in HSCs. Leptin induced GATA-2 expression in HSCs in vitro and in vivo. GATA-2 mediated leptin inhibition of PPARγ1 expression by its binding site in PPARγ1 promoter in HSCs and GATA-2 promoted HSC activation. Leptin upregulated GATA-2 expression through β-catenin and sonic hedgehog pathways in HSCs. Leptin-induced increase in GATA-2 was accompanied by the decrease in PPARγ expression in HSCs and by the increase in the activated HSC number and liver fibrosis in vivo. Our data might suggest a possible new explanation for the promotion effect of leptin on liver fibrogenesis.

Calcineurin and CRTC2 mediate FSH and TGFβ1 upregulation of Cyp19a1 and Nr5a in ovary granulosa cells

Estrogens are essential for female reproduction and overall well-being, and estrogens in the circulation are largely synthesized in ovarian granulosa cells. Using primary cultures of ovarian granulosa cells from gonadotropin-primed immature rats, we have recently discovered that pituitary FSH and ovarian cytokine transforming growth factor beta 1 (TGFβ1) induce calcineurin-mediated dephosphorylation-activation of cAMP-response element-binding protein (CREB)-regulated transcription coactivator (CRTC2) to modulate the expression of Star, Cyp11a1, and Hsd3b leading to increased production of progesterone. This study explored the role of calcineurin and CRTC2 in FSH and TGFβ1 regulation of Cyp19a1 expression in granulosa cells. Ovarian granulosa cells treated with FSH displayed increased aromatase protein at 24  h post-treatment, which subsided by 48  h, while TGFβ1 acting through its type 1 receptor augmented the action of FSH with a greater and longer effects. It is known that the ovary-specific Cyp19a1 PII-promoter contains crucial response elements for CREB and nuclear receptor NR5A subfamily liver receptor homolog 1 (LRH1/NR5A2) and steroidogenic factor 1 (SF1/NR5A1), and that the Nr5a2 promoter also has a potential CREB-binding site. Herein, we demonstrate that FSH+TGFβ1 increased LRH1 and SF1 protein levels, and their binding to the Cyp19a1 PII-promoter evidenced, determined by chromatin immunoprecipitation analysis. Moreover, pretreatment with calcineurin auto-inhibitory peptide (CNI) abolished the FSH+TGFβ1-upregulated but not FSH-upregulated aromatase activity at 48  h, and the corresponding mRNA changes in Cyp19a1, and Nr5a2 and Nr5a1 at 24  h. In addition, FSH and TGFβ1 increased CRTC2 binding to the Cyp19a1 PII-promoter and Nr5a2 promoter at 24  h, with CREB bound constitutively. In summary, the results of this study indicate that calcineurin and CRTC2 have important roles in mediating FSH and TGFβ1 collateral upregulation of Cyp19a1 expression together with its transcription regulators Nr5a2 and Nr5a1 in ovarian granulosa cells.

A comprehensive transcriptomic analysis of infant and adult mouse ovary

Ovary development is a complex process involving numerous genes. A well-developed ovary is essential for females to keep fertility and reproduce offspring. In order to gain a better insight into the molecular mechanisms related to the process of mammalian ovary development, we performed a comparative transcriptomic analysis on ovaries isolated from infant and adult mice by using next-generation sequencing technology (SOLiD). We identified 15,454 and 16,646 transcriptionally active genes at the infant and adult stage, respectively. Among these genes, we also identified 7021 differentially expressed genes. Our analysis suggests that, in general, the adult ovary has a higher level of transcriptomic activity. However, it appears that genes related to primordial follicle development, such as those encoding Figla and Nobox, are more active in the infant ovary, whereas expression of genes vital for follicle development, such as Gdf9, Bmp4 and Bmp15, is upregulated in the adult. These data suggest a dynamic shift in gene expression during ovary development and it is apparent that these changes function to facilitate follicle maturation, when additional functional gene studies are considered. Furthermore, our investigation has also revealed several important functional pathways, such as apoptosis, MAPK and steroid biosynthesis, that appear to be much more active in the adult ovary compared to those of the infant. These findings will provide a solid foundation for future studies on ovary development in mice and other mammals and help to expand our understanding of the complex molecular and cellular events that occur during postnatal ovary development.

Transgenic mouse models in the study of reproduction: insights into GATA protein function

For the past 2 decades, transgenic technology in mice has allowed for an unprecedented insight into the transcriptional control of reproductive development and function. The key factor among the mouse genetic tools that made this rapid advance possible is a conditional transgenic approach, a particularly versatile method of creating gene deletions and substitutions in the mouse genome. A centerpiece of this strategy is an enzyme, Cre recombinase, which is expressed from defined DNA regulatory elements that are active in the tissue of choice. The regulatory DNA element (either genetically engineered or natural) assures Cre expression only in predetermined cell types, leading to the guided deletion of genetically modified (flanked by loxP or ‘floxed’ byloxP) gene loci. This review summarizes and compares the studies in which genes encoding GATA family transcription factors were targeted either globally or by Cre recombinases active in the somatic cells of ovaries and testes. The conditional gene loss experiments require detailed knowledge of the spatial and temporal expression of Cre activity, and the challenges in interpreting the outcomes are highlighted. These studies also expose the complexity of GATA-dependent regulation of gonadal gene expression and suggest that gene function is highly context dependent.

HER2 and GATA4 are new prognostic factors for early-stage ovarian granulosa cell tumor-a long-term follow-up study

Granulosa cell tumors (GCTs) carry a risk of recurrence also at an early stage, but reliable prognostic factors are lacking. We assessed clinicopathological prognostic factors and the prognostic roles of the human epidermal growth factor receptors (HER 2–4) and the transcription factor GATA4 in GCTs. We conducted a long-term follow-up study of 80 GCT patients with a mean follow-up time of 16.8 years. A tumor-tissue microarray was immunohistochemically stained for HER2–4 and GATA4. Expression of HER2–4 mRNA was studied by means of real time polymerase chain reaction and HER2 gene amplification was analyzed by means of silver in situ hybridization. The results were correlated to clinical data on recurrences and survival. We found that GCTs have an indolent prognosis, with 5-year disease-specific survival (DSS) being 97.5%. Tumor recurrence was detected in 24% of the patients at a median of 7.0 years (range 2.6–18 years) after diagnosis. Tumor stage was not prognostic of disease-free survival (DFS). Of the molecular prognostic factors, high-level expression of HER2, and GATA4, and high nuclear atypia were prognostic of shorter DFS. In multivariate analyses, high-level coexpression of HER2 and GATA4 independently predicted DFS (hazard ratio [HR] 8.75, 95% CI 2.20–39.48, P = 0.002). High-level expression of GATA4 also predicted shorter DSS (HR 3.96, 95% CI 1.45–12.57, P = 0.006). In multivariate analyses, however, tumor stage (II–III) and nuclear atypia were independent prognostic factors of DSS. In conclusion HER2 and GATA4 are new molecular prognostic markers of GCT recurrence, which could be utilized to optimize the management and follow-up of patients with early-stage GCTs.

Transcription factors GATA-4 and GATA-6: molecular characterization, expression patterns and possible functions during goose (Anser cygnoides) follicle development

The transcription factors GATA-4 and GATA-6, members of the GATA family, play an important role in ovarian cell proliferation, differentiation and apoptosis. In this study, the full-length coding sequences of goose GATA-4 and GATA-6 were cloned and characterized. GATA-4 and GATA-6 consist of 1236 and 1104 nucleotides encoding proteins with 411 and 367 amino acids, respectively. The deduced amino acid sequences of both proteins include two adjacent zinc finger domains with the distinctive form (CVNC-X17-CNAC)-X29-(CANC-X17-CNAC) and share 84.76% identity within this domain. In silico prediction together with matching of the high affinity RRXS(T)Y motif revealed that the GATA-4 protein might be phosphorylated predominantly at S(233), but no phosphorylation site was found in the GATA-6 protein. Real-time quantitative PCR analysis showed that GATA-4 and GATA-6 mRNAs were co-expressed in goose follicles, moderately expressed in granulosa cells and weakly expressed in theca cells. The expression level of GATA-4 mRNA in healthy follicles was significantly higher than in atretic follicles or postovulatory follicles (P<0.01), and the expression level of GATA-6 mRNA in healthy follicles was significantly lower than in atretic follicles or postovulatory follicles (P<0.01). The expression level of GATA-4 mRNA in granulosa cells was downregulated during follicle development; the peak of expression occurred in the 8-10 mm follicles, and the lowest expression was in the F1 follicles. GATA-6 was upregulated and reached its peak expression in the F1 follicles. These results indicate that the molecular structural differences in goose GATA-4 and GATA-6 may be related to their different roles during follicle development.

The global effect of follicle-stimulating hormone and tumour necrosis factor α on gene expression in cultured bovine ovarian granulosa cells

BACKGROUND

Oocytes mature in ovarian follicles surrounded by granulosa cells. During follicle growth, granulosa cells replicate and secrete hormones, particularly steroids close to ovulation. However, most follicles cease growing and undergo atresia or regression instead of ovulating. To investigate the effects of stimulatory (follicle-stimulating hormone; FSH) and inhibitory (tumour necrosis factor alpha; TNFα) factors on the granulosa cell transcriptome, bovine ovaries were obtained from a local abattoir and pools of granulosa cells were cultured in vitro for six days under defined serum-free conditions with treatments present on days 3-6. Initially dose-response experiments (n = 4) were performed to determine the optimal concentrations of FSH (0.33 ng/ml) and TNFα (10 ng/ml) to be used for the microarray experiments. For array experiments cells were cultured under control conditions, with FSH, with TNFα, or with FSH plus TNFα (n = 4 per group) and RNA was harvested for microarray analyses.

RESULTS

Statistical analysis showed primary clustering of the arrays into two groups, control/FSH and TNFα/TNFα plus FSH. The effect of TNFα on gene expression dominated that of FSH, with substantially more genes differentially regulated, and the pathways and genes regulated by TNFα being similar to those of FSH plus TNFα treatment. TNFα treatment reduced the endocrine activity of granulosa cells with reductions in expression of FST, INHA, INBA and AMH. The top-ranked canonical pathways and GO biological terms for the TNFα treatments included antigen presentation, inflammatory response and other pathways indicative of innate immune function and fibrosis. The two most significant networks also reflect this, containing molecules which are present in the canonical pathways of hepatic fibrosis/hepatic stellate cell activation and transforming growth factor β signalling, and these were up regulated. Upstream regulator analyses also predicted TNF, interferons γ and β1 and interleukin 1β.

CONCLUSIONS

In vitro, the transcriptome of granulosa cells responded minimally to FSH compared with the response to TNFα. The response to TNFα indicated an active process akin to tissue remodelling as would occur upon atresia. Additionally there was reduction in endocrine function and induction of an inflammatory response to TNFα that displays features similar to immune cells.

FOXL2, GATA4, and SMAD3 co-operatively modulate gene expression, cell viability and apoptosis in ovarian granulosa cell tumor cells

Aberrant ovarian granulosa cell proliferation and apoptosis may lead to granulosa cell tumors (GCT), the pathogenesis of which involves transcription factors GATA4, FOXL2, and SMAD3. FOXL2 gene harbors a point mutation (C134W) in a vast majority of GCTs. GATA4 is abundantly expressed in GCTs and its expression correlates with poor prognosis. The TGF-β mediator SMAD3 promotes GCT cell survival through NF-κB activation, and interacts with FOXL2. Here, we find that the expression patterns of these factors overlap in the normal human ovary and 90 GCTs, and positively correlate with each other and with their mutual target gene CCND2, which is a key factor for granulosa cell proliferation. We have explored the molecular interactions of FOXL2, GATA4, and SMAD3 and their roles in the regulation of CCND2 using co-immunoprecipitation, promoter transactivation, and cell viability assays in human GCT cells. We found that not only SMAD3, but also GATA4 physically interact with both wild type and C134W-mutated FOXL2. GATA4 and SMAD3 synergistically induce a 8-fold increase in CCND2 promoter transactivation, which is 50% reduced by both FOXL2 types. We confirmed that wild type FOXL2 significantly decreases cell viability. Interestingly, GATA4 and SMAD3 caused a marked reduction of GCT cell apoptosis induced by wild type FOXL2. Thus, the effects of GATA4 and SMAD3 on both cell viability and apoptosis are distinct from those of wild type FOXL2; a perturbation of this balance due to the oncogenic FOXL2 mutation is likely to contribute to GCT pathogenesis.

GATA4 and GATA6 silencing in ovarian granulosa cells affects levels of mRNAs involved in steroidogenesis, extracellular structure organization, IGF-I activity, and apoptosis

Knockdown of the transcription factors GATA4 and GATA6 in granulosa cells (GCs) impairs folliculogenesis and induces infertility. To investigate the pathways and genes regulated by these factors, we performed microarray analyses on wild-type GCs or GCs lacking GATA4, GATA6, or GATA4/6 (G4(gcko), G6(gcko), and G4/6(gcko)) after in vivo treatment with equine chorionic gonadotropin. GATA4 deletion affected a greater number of genes than GATA6, which correlates with the subfertility observed in G4(gcko) mice and the normal reproductive function found in G6(gcko) animals. An even greater number of genes were affected by the deletion of both factors. Moreover, the expression of FSH receptor, LH receptor, inhibin α and β, versican, pregnancy-associated plasma protein A, and the regulatory unit 2b of protein kinase A, which are known to be crucial for ovarian function, was greatly affected in double GATA4 and GATA6 knockouts when compared with single GATA-deficient animals. This suggests that GATA4 and GATA6 functionally compensate for each other in the regulation of key ovarian genes. Functional enrichment revealed that ovulation, growth, intracellular signaling, extracellular structure organization, gonadotropin and growth factor actions, and steroidogenesis were significantly regulated in G4/6(gcko) mice. The results of this analysis were confirmed using quantitative polymerase chain reaction, immunohistochemical, and biological assays. Treatment of GCs with cAMP/IGF-I, to bypass FSH and IGF-I signaling defects, revealed that most of the affected genes are direct targets of GATA4/6. The diversity of pathways affected by the knockdown of GATA underscores the important role of these factors in the regulation of GC function.

FSH modulates the expression of inhibin-alpha and the secretion of inhibins via orphan nuclear receptor NUR77 in ovarian granulosa cells

It has been previously reported that follicle-stimulating hormone (FSH) regulates the expression of inhibin-alpha in human granulosa cells, but the precise molecular pathway remains unknown. In the present study, we investigated the role of the orphan nuclear receptor, NUR77, in both the transcriptional regulation of the inhibin α-subunit gene and the secretion of inhibins. Our results showed that in a human granulosa cell tumor-derived cell line (KGN) and in human granulosa-lutein cells (hGL), FSH induced the expression of NUR77 and inhibin-alpha, although inhibin-alpha expression did not increased following FSH treatment if NUR77 was knocked down. Furthermore, simply overexpressing or reducing NUR77 levels affected inhibin-alpha expression, while NUR77 overexpression improved the secretion of inhibin A and B from human granulosa cells. In addition, chromatin immunoprecipitation-PCR, avidin-biotin-conjugated DNA precipitation, and luciferase reporter assays confirmed that NUR77 directly regulated the transcription of the inhibin-alpha gene through the specific NGFI-B response element located within its promoter. In the ovarian granulosa cells of the Nur77 knockout mice, the mRNA levels of inhibin-alpha were decreased relative to wild-type mice. These data indicate a role of NUR77 in the regulation of inhibin-alpha in ovarian granulosa cells.

Expression of Wnt and TGF-β pathway components and key adrenal transcription factors in adrenocortical tumors: association to carcinoma aggressiveness

Factors controlling benign and malignant adrenocortical tumorigenesis are largely unknown, but several mouse models suggest an important role for inhibin-alpha (INHA). To show that findings in the mouse are relevant to human tumors and clinical outcome, we investigated the expression of signaling proteins and transcription factors involved in the regulation of INHA in human tumor samples⋅ Thirty-one adrenocortical tumor samples, including 13 adrenocortical carcinomas (ACCs), were categorized according to Weiss score, hormonal profile, and patient survival data and analyzed using immunohistochemistry and RT-PCR. Expression of the TGF-β signaling mediator SMAD3 varied inversely with Weiss score, so that SMAD3 expression was lowest in the most malignant tumors. By contrast, SMAD2 expression was upregulated in most malignant tumors. Wnt pathway co-receptors LRP5 and LRP6 were predominantly expressed in benign adrenocortical tumors. In ACCs, expression of transcription factors GATA-6 and SF-1 correlated with that of their target gene INHA. Moreover, the diminished expression of GATA-6 and SF-1 in ACCs correlated with poor outcome. We conclude that the factors driving INHA expression are reduced in ACCs with poor outcome, implicating a role for INHA as a tumor suppressor in humans.

Betaglycan alters NFκB-TGFβ2 cross talk to reduce survival of human granulosa tumor cells

The molecular pathways controlling granulosa cell tumor (GCT) survival are poorly understood. In many cell types, nuclear factor-κB (NFκB) and TGFβ coordinately regulate cell survival to maintain tissue homeostasis. Because GCT cell lines exhibit constitutively activated NFκB, we hypothesized that NFκB blocks TGFβ-mediated cell death in GCT cells. To test this hypothesis, we used the human GCT cell line KGN, which exhibits loss of betaglycan, a TGFβ co-receptor. After inhibition of NFκB in KGN cells, re-expression of betaglycan resulted in a decrease in cell viability, which was further decreased by TGFβ2. Intriguingly, TGFβ2 increased NFκB reporter activity in control cells, but betaglycan expression suppressed both basal and TGFβ2-stimulated NFκB activity. Chemical inhibition of Mothers against decapentaplegic homolog 2/3 (SMAD2/3) signaling or SMAD2/3 gene silencing revealed that both SMADs contributed to cell survival. Furthermore, inhibiting NFκB activity resulted in a specific reduction in SMAD3 expression. Conversely, overexpression of SMAD3 increased basal NFκB activity and countered betaglycan-mediated suppression of NFκB activity. Finally, ERK1/2 activation emerged as the point of convergence of NFκB, SMAD3, and TGFβ2/betaglycan governance of GCT cell viability. Key findings in KGN cells were reproduced in a second GCT cell line, COV434. Collectively, our data establish that both SMAD2/3 and NFκB signaling pathways support GCT cell viability and suggest the existence of a positive feedback loop between NFκB and SMAD3 signaling in late-stage GCT. Furthermore, our data suggest that loss of betaglycan during tumor progression in GCT alters the functional outcomes generated by NFκB and TGFβ pathway cross talk.

Luteinizing hormone regulates inhibin-α subunit expression through multiple signaling pathways involving steroidogenic factor-1 and beta-catenin in the macaque corpus luteum

We employed different experimental model systems to define the role of GATA4, beta-catenin, and steroidogenic factor (SF-1) transcriptional factors in the regulation of monkey luteal inhibin secretion. Reverse transcription polymerase chain reactions and western blotting analyses show high expression of inhibin-α, GATA4, and beta-catenin in corpus luteum (CL) of the mid-luteal phase. Gonadotropin-releasing hormone receptor antagonist-induced luteolysis model suggested the significance of luteinizing hormone (LH) in regulating these transcriptional factors. Inducible cyclic AMP early repressor mRNA expression was detected in the CL and no change was observed in different stages of CL. Following amino acid sequence analysis, interaction between SF-1 and beta-catenin in mid-stage CL was verified by reciprocal co-immunoprecipitation experiments coupled to immunoblot analysis. Electrophoretic mobility shift analysis support the role of SF-1 in regulating luteal inhibin-α expression. Our results suggest a possible multiple crosstalk of Wnt, cAMP, and SF-1 in the regulation of luteal inhibin secretion.

GATA4 is involved in the gonadal development and maturation of the teleost fish tilapia, Oreochromis niloticus

GATA4, a member of the GATA family, is a well-known transcription factor implicated in the regulation of sex determination and sexual differentiation in mammals. However, little is known about the possible role of GATA4 in fish reproduction. In the present study, a full-length GATA4 cDNA from the tilapia was cloned and characterized. The tilapia GATA4 gene contained an open reading frame (ORF) of 1179 nucleotides encoding a protein of 392 amino acids. Sequence alignment revealed that the tilapia GATA4 protein shared higher homology (ranging from 63.1 to 74.6%) with other vertebrates. RT-PCR analysis indicated that the GATA4 gene is expressed in the ovary, testis, liver, intestine and heart in adult tilapia. In situ hybridization was performed to examine the temporal and spatial expression patterns of GATA4 during tilapia gonadal differentiation and development. In the undifferentiated gonad, GATA4 was expressed in the somatic cells of both sexes. Subsequently, GATA4 expression persisted in the differentiated, juvenile and adult ovary and testis in tilapia. Our data indicate for the first time that GATA4 is not only necessary for the onset of gonadal differentiation, but also important for gonadal development and maturation.

Expression of Transcription Factor GATA-6 in Alveolar Epithelial Cells Is Linked to Neonatal Lung Disease

BACKGROUND

Premature birth and respiratory distress syndrome (RDS) are risk factors for disturbed lung development and bronchopulmonary dysplasia (BPD). The molecular mechanisms related to prematurity and BPD remain largely unknown. Epithelial expression of the transcription factor GATA-6 has been implicated in normal and abnormal murine lung development.

OBJECTIVES

The possible involvement of GATA-6 in the normal development and in RDS and BPD was investigated in the human and baboon lung.

METHODS

Immunohistochemistry was used to study the expression of GATA-6 and thyroid transcription factor 1 in lung specimens from different age groups of human and baboon fetuses and newborns with lung disease. Furthermore, the regulatory role of TGF-β₁ in GATA-6 expression was investigated in human pulmonary epithelial cell lines using RT-PCR.

RESULTS

GATA-6 expression increased in the developing human airway epithelium along with advancing gestation, but diminished to negligible at birth. In RDS, GATA-6 expression was enhanced at 5-7 days after birth, and decreased thereafter. In BPD, the expression of GATA-6 in alveolar epithelial cells was low. These results were confirmed and extended using an established baboon model of prematurity. The in vitro experiments revealed that TGF-β₁ induces GATA-6 and thyroid transcription factor 1 expression in lung epithelial cells.

CONCLUSIONS

Our results suggest that the expression of GATA-6 at the early stages of the preterm lung may be related to impaired postnatal alveolar development.

GATA transcription factors in the developing reproductive system

Previous work has firmly established the role for both GATA4 and FOG2 in the initial global commitment to sexual fate, but their (joint or individual) function in subsequent steps remained unknown. Hence, gonad-specific deletions of these genes in mice were required to reveal their roles in sexual development and gene regulation. The development of tissue-specific Cre lines allowed for substantial advances in the understanding of the function of GATA proteins in sex determination, gonadal differentiation and reproductive development in mice. Here we summarize the recent work that examined the requirement of GATA4 and FOG2 proteins at several critical stages in testis and ovarian differentiation. We also discuss the molecular mechanisms involved in this regulation through the control of Dmrt1 gene expression in the testis and the canonical Wnt/ß-catenin pathway in the ovary.

Transcription factors and ovarian functions

This study represents a first review of contemporarily knowledge concerning involvement of transcription factors in control of different ovarian functions. After introduction of basic functions and classification of transcription factors, the available data concerning involvement of transcription factors in control of the following ovarian events are present: follicular development and selection, ovarian cell proliferation and cancerogenesis, ovarian cell apoptosis, ovarian secretory activity, oocyte/cumulus maturation, ovulation and luteogenesis, mediation effect of hormones, growth factors, and cytokines. The importance of transcription factors of Smad family, of forkhead transcription factor (Fox) family, of breast cancer-associated genes/transcription factor, hypoxia-induced transcription factors and of other transcription factors in control of these processes has been demonstrated.

The regulation of TGFbeta signal transduction

Transforming growth factor beta (TGFbeta) pathways are implicated in metazoan development, adult homeostasis and disease. TGFbeta ligands signal via receptor serine/threonine kinases that phosphorylate, and activate, intracellular Smad effectors as well as other signaling proteins. Oligomeric Smad complexes associate with chromatin and regulate transcription, defining the biological response of a cell to TGFbeta family members. Signaling is modulated by negative-feedback regulation via inhibitory Smads. We review here the mechanisms of TGFbeta signal transduction in metazoans and emphasize events crucial for embryonic development.

An integrative ChIP-chip and gene expression profiling to model SMAD regulatory modules

Background

The TGF-β/SMAD pathway is part of a broader signaling network in which crosstalk between pathways occurs. While the molecular mechanisms of TGF-β/SMAD signaling pathway have been studied in detail, the global networks downstream of SMAD remain largely unknown. The regulatory effect of SMAD complex likely depends on transcriptional modules, in which the SMAD binding elements and partner transcription factor binding sites (SMAD modules) are present in specific context.

Results

To address this question and develop a computational model for SMAD modules, we simultaneously performed chromatin immunoprecipitation followed by microarray analysis (ChIP-chip) and mRNA expression profiling to identify TGF-β/SMAD regulated and synchronously coexpressed gene sets in ovarian surface epithelium. Intersecting the ChIP-chip and gene expression data yielded 150 direct targets, of which 141 were grouped into 3 co-expressed gene sets (sustained up-regulated, transient up-regulated and down-regulated), based on their temporal changes in expression after TGF-β activation. We developed a data-mining method driven by the Random Forest algorithm to model SMAD transcriptional modules in the target sequences. The predicted SMAD modules contain SMAD binding element and up to 2 of 7 other transcription factor binding sites (E2F, P53, LEF1, ELK1, COUPTF, PAX4 and DR1).

Conclusion

Together, the computational results further the understanding of the interactions between SMAD and other transcription factors at specific target promoters, and provide the basis for more targeted experimental verification of the co-regulatory modules.

Transcription factor GATA-6 is expressed in quiescent myofibroblasts in idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) (histopathology of usual interstitial pneumonia [UIP]) is a progressive disease with poor prognosis. Characteristic features of IPF/UIP include fibroblastic foci, which are patchy lesions of focal, disarranged myofibroblasts. GATA-6 is a transcription factor linked with cell differentiation. Its role in the development of IPF has not previously been investigated. We hypothesized that GATA-6 participates in the differentiation of fibroblasts into myofibroblasts in IPF/UIP lungs. The expression patterns of GATA-6, the mesenchymal marker alpha-smooth muscle actin (alpha-SMA), and markers for proliferation (Ki67) and apoptosis (caspase-3) were analyzed in human IPF/UIP tissue samples. The effects of GATA-6 overexpression and silencing were studied in cell cultures. The results show that the alpha-SMA-positive fibroblastic foci in IPF/UIP lungs are positive for GATA-6, but negative for Ki67 and caspase-3. Cultured human IPF/UIP fibroblasts expressed GATA-6 mRNA, whereas cells from the normal adult lung did not. In cultured A549 lung epithelial cells, the induction of GATA-6 by transforming growth factor-beta1 resulted in simultaneous expression of alpha-SMA and decrease of E-cadherin. The inhibition of GATA-6 expression in fibroblasts showed that GATA-6 mediates the alpha-SMA-inducing signal of transforming growth factor-beta1. In conclusion, the hallmark of IPF/UIP histopathology, the fibroblast focus, consists of differentiated, quiescent cells that prominently express GATA-6.

GATA4 is a regulator of astrocyte cell proliferation and apoptosis in the human and murine central nervous system

The GATA transcription factors consist of six family members, which bind to the consensus DNA-binding element, W-GATA-R, and are poorly characterized in the central nervous system (CNS). Using retroviral gene trapping on transgenic mouse glioma models, we identified GATA6 to be a novel tumor suppressor gene in glioblastoma multiforme. We now show GATA4, a family member of GATA6, to be expressed in the neurons and glia of normal murine and human embryonic and adult CNS. Silencing GATA4 in normal astrocytes did not alter their growth properties. In contrast, knockdown of Gata4 in p53 null non-transformed murine astrocytes induced transformation, with increased proliferation and resistance to chemotherapy or radiation-induced apoptosis. Furthermore, GATA4 expression was lost in a panel of human malignant astrocytoma cell lines. GATA4 overexpression in normal human and murine astrocytes resulted in a cell cycle block in G1 phase, with increased apoptosis. Mechanistically, GATA4 was a transcriptional inducer of the cyclin-dependent kinase inhibitor, p15INK4B, leading to the attenuation of cyclin D1. GATA4 expression was also induced by transforming growth factor-beta, leading to the inhibition of astrocyte proliferation. Collectively, we show that GATA4 is expressed in the embryonic and adult CNS and acts as a negative regulator of astrocyte proliferation and growth.

Enhanced expression of transcription factor GATA-4 in inflammatory bowel disease and its possible regulation by TGF-beta1

BACKGROUND

Transforming growth factor beta 1 (TGF-beta1) promotes epithelial healing in inflammatory bowel disease. We hypothesized that GATA-4, a transcription factor cooperating with TGF-beta signaling pathway, is upregulated by TGF-beta1 in the inflamed intestinal epithelium.

METHODS

Normal and inflamed intestinal samples were subjected to immunohistochemistry for GATA-4/6 and the TGF-beta signaling pathway components Smad2/3/4. Proliferation and apoptosis were analyzed using Ki-67 and in situ DNA 3'-end labeling assays and Bax and Bcl-2 immunohistochemistry. Furthermore, GATA-4 was assessed in intestinal Caco-2 cells stimulated with TGF-beta1, or interleukin-6 and tumor necrosis factor alpha.

RESULTS

GATA-4 was detected in only 20% of normal intestinal samples, but was upregulated in corresponding inflamed regions. GATA-6 expression remained unchanged during inflammation. TGF-beta1 and Smad3/4, but not Smad2, were expressed concomitantly with GATA-4 in inflamed bowel mucosa. In intestinal Caco-2 cells, TGF-beta1 upregulated GATA-4 and Smad2/3/4, whereas treatment with control cytokines had no effect. Inflammation was associated with increased epithelial cell apoptosis and the enhancement of Bcl-2, but not Bax.

CONCLUSIONS

We surmise GATA-4 expression is upregulated in inflamed intestine correlating with the activation of TGF-beta signaling pathway. We speculate that TGF-beta1 drives GATA-4 expression during intestinal inflammation, these two components cooperating to promote epithelial healing.

GATA-4 regulates Bcl-2 expression in ovarian granulosa cell tumors

Excessive cell proliferation and decreased apoptosis have been implicated in the pathogenesis of ovarian granulosa cell tumors (GCTs). We hypothesized that transcription factor GATA-4 controls expression of the antiapoptotic factor Bcl-2 and the cell cycle regulator cyclin D2 in normal and neoplastic granulosa cells. To test this hypothesis, a tissue microarray based on 80 GCTs was subjected to immunohistochemistry for GATA-4, Bcl-2, and cyclin D2, and the data were correlated to clinical and histopathological parameters. In addition, quantitative RT-PCR for GATA-4, Bcl-2, and cyclin D2 was performed on 21 human GCTs. A mouse GCT model was used to complement these studies. The role of GATA-4 in the regulation of Bcl2 and ccdn2 (coding for cyclin D2) was studied by transactivation assays, and by disrupting GATA-4 function with dominant negative approaches in mouse and human GCT cell lines. We found that GATA-4 expression correlated with Bcl-2 and cyclin D2 expression in human and murine GCTs. Moreover, GATA-4 enhanced Bcl-2 and cyclin D2 promoter activity in murine GCT cells. Whereas GATA-4 overexpression up-regulated and dominant negative GATA-4 suppressed Bcl-2 expression in human GCT cells, the effects on cyclin D2 were negligible. Our results reveal a previously unknown relationship between GATA-4 and Bcl-2 in mammalian granulosa cells and GCTs, and suggest that GATA-4 influences granulosa cell fate by transactivating Bcl-2.

Role of the GATA family of transcription factors in endocrine development, function, and disease

The WGATAR motif is a common nucleotide sequence found in the transcriptional regulatory regions of numerous genes. In vertebrates, these motifs are bound by one of six factors (GATA1 to GATA6) that constitute the GATA family of transcriptional regulatory proteins. Although originally considered for their roles in hematopoietic cells and the heart, GATA factors are now known to be expressed in a wide variety of tissues where they act as critical regulators of cell-specific gene expression. This includes multiple endocrine organs such as the pituitary, pancreas, adrenals, and especially the gonads. Insights into the functional roles played by GATA factors in adult organ systems have been hampered by the early embryonic lethality associated with the different Gata-null mice. This is now being overcome with the generation of tissue-specific knockout models and other knockdown strategies. These approaches, together with the increasing number of human GATA-related pathologies have greatly broadened the scope of GATA-dependent genes and, importantly, have shown that GATA action is not necessarily limited to early development. This has been particularly evident in endocrine organs where GATA factors appear to contribute to the transcription of multiple hormone-encoding genes. This review provides an overview of the GATA family of transcription factors as they relate to endocrine function and disease.

Cooperation between GATA4 and TGF-beta signaling regulates intestinal epithelial gene expression

Members of the transforming growth factor-beta (TGF-beta) family have been shown to play an important role in the regulation of gut epithelial gene expression. We have used the intestinal alkaline phosphatase (IAP) and intestinal fatty acid binding protein (IFABP) promoters to dissect the mechanisms by which TGF-beta1 signaling regulates gut epithelial gene expression. TGF-beta signaling alone was not sufficient for activation of IAP and IFABP promoters. However, TGF-beta signaling cooperated with the gut epithelial transcription factor GATA4 to synergistically activate IAP and IFABP promoters. Coexpression of GATA4 along with the TGF-beta1 signal transducing downstream effectors such as Smad2, 3, and 4 resulted in synergistic activation of both IAP and IFABP promoters. This synergistic activation was reduced by simultaneous expression of dominant-negative Smad4. -40 and -89 GATA binding sites in the IFABP promoter were required for the synergistic activation by Smad2, 3, and 4 and GATA4. GATA4 and Smad2, 3, and 4 physically associated with each other and this interaction was mediated through the MH2 domain of Smad2, 3, and 4 and the second zinc finger and the COOH-terminal basic domain of GATA4. The COOH-terminal activation domain and the Smad-interacting second zinc finger domain of GATA4 were required for the synergistic activation of the IFABP promoter. Naturally occurring oncogenic mutations within the GATA4-interacting MH2 domain of Smad2 reduced the coactivation of IFABP promoter by Smad2 and GATA4. Our results suggest that the TGF-beta signaling regulates gut epithelial gene expression by targeting GATA4.

Adrenocortical tumorigenesis, luteinizing hormone receptor and transcription factors GATA-4 and GATA-6

Luteinizing hormone (LH/hCG) responsiveness of normal and pathological human adrenal glands as well as the possibility of constitutive expressions of luteinizing hormone receptor (LHR) in adrenal cortex has been reported. Some recent studies showed a correlation between the LHR and abundant GATA-4 expression in both metastasizing and non-metastasizing human adrenocortical tumors, but not in normal adrenals, implicating the putative relevance of LHR and GATA-4 for adrenocortical pathophysiology. However, the physio- and pathophysiological significance of LHR and GATA-4 in the mechanism of adrenocortical tumorigenesis remains unclear. The paucity of suitable models for adrenal tumorigenesis makes the establishment of proper animal models highly important. LHR expression in the murine adrenal gland is an exception and not found in wild-type (WT) animal. We have previously shown that ectopic LHR expression in the murine adrenal gland can be induced by chronically elevated LH levels. We have generated a gonadotropin-responsive adrenal tumor model in gonadectomized transgenic (TG) mice expressing the inhibin alpha promoter/Simian Virus 40 T antigen transgene (inhalpha/Tag). Given the induction of expression and regulation of GATA-4 and GATA-6 zinc finger transcription factors in the gonads by gonadotropins, this review will explore their relationship to LHR expression and their role in adrenocortical tumorigenesis. A functional link between LHR and GATA-4 actions in the adrenal pathophysiology is proposed.