Luteinizing hormone deficiency and female infertility in mice lacking the transcription factor NGFI-A (Egr-1)

Comparison of Steroidogenic and Ovulation-Inducing Effects of Orthosteric and Allosteric Agonists of Luteinizing Hormone/Chorionic Gonadotropin Receptor in Immature Female Rats

Gonadotropins, including human chorionic gonadotropin (hCG), are used to induce ovulation, but they have a number of side effects, including ovarian hyperstimulation syndrome (OHSS). A possible alternative is allosteric luteinizing hormone (LH)/hCG receptor agonists, including the compound TP4/2 we developed, which remains active when administered orally. The aim was to study the effectiveness of TP4/2 (orally, 40 mg/kg) as an ovulation inducer in FSH-stimulated immature female rats, compared with hCG (s.c., 15 IU/rat). TP4/2 stimulated progesterone production and corpus luteum formation; time-dependently increased the ovarian expression of steroidogenic genes (Star, Cyp11a1, Cyp17a1) and genes involved in ovulation regulation (Adamts-1, Cox-2, Egr-1, Mt-1); and increased the content of metalloproteinase ADAMTS-1 in the ovaries. These effects were similar to those of hCG, although in some cases they were less pronounced. TP4/2, in contrast to hCG, maintained normal LH levels and increased the ovarian expression of the LH/hCG receptor gene, indicating preservation of ovarian sensitivity to LH, and did not cause a sustained increase in expression of vascular endothelial growth factor-A involved in OHSS. Thus, TP4/2 is an effective ovulation inducer that, unlike hCG, has a lower risk of OHSS and ovarian LH resistance due to its moderate stimulating effect on steroidogenesis.

Sex-Linked Growth Disorder and Aberrant Pituitary Gene Expression in Nestin-Cre-Mediated Egr1 Conditional Knockout Mice

Genes that regulate hormone release are essential for maintaining metabolism and energy balance. Egr1 encodes a transcription factor that regulates hormone production and release, and a decreased in growth hormones has been reported in Egr1 knockout mice. A reduction in growth hormones has also been observed in Nestin-Cre mice, a model frequently used to study the nervous system. Currently, it is unknown how Egr1 loss or the Nestin-Cre driver disrupt pituitary gene expression. Here, we compared the growth curves and pituitary gene expression profiles of Nestin-Cre-mediated Egr1 conditional knockout (Egr1cKO) mice with those of their controls. Reduced body weight was observed in both the Nestin-Cre and Egr1cKO mice, and the loss of Egr1 had a slightly more severe impact on female mice than on male mice. RNA-seq data analyses revealed that the sex-related differences were amplified in the Nestin-Cre-mediated Egr1 conditional knockout mice. Additionally, in the male mice, the influence of Egr1cKO on pituitary gene expression may be overridden by the Nestin-Cre driver. Differentially expressed genes associated with the Nestin-Cre driver were significantly enriched for genes related to growth factor activity and binding. Altogether, our results demonstrate that Nestin-Cre and the loss of Egr1 in the neuronal cell lineage have distinct impacts on pituitary gene expression in a sex-specific manner.

A CRISPR/Cas9-engineered mouse carrying a conditional knockout allele for the early growth response-1 transcription factor

Early growth response 1 (EGR1) mediates transcriptional programs that are indispensable for cell division, differentiation, and apoptosis in numerous physiologies and pathophysiologies. Whole-body EGR1 knockouts in mice (Egr1KO ) have advanced our understanding of EGR1 function in an in vivo context. To extend the utility of the mouse to investigate EGR1 responses in a tissue- and/or cell-type-specific manner, we generated a mouse model in which exon 2 of the mouse Egr1 gene is floxed by CRISPR/Cas9 engineering. The floxed Egr1 alleles (Egr1f/f ) are designed to enable spatiotemporal control of Cre-mediated EGR1 ablation in the mouse. To confirm that the Egr1f/f alleles can be abrogated using a Cre driver, we crossed the Egr1f/f mouse with a global Cre driver to generate the Egr1 conditional knockout (Egr1d/d ) mouse in which EGR1 expression is ablated in all tissues. Genetic and protein analysis confirmed the absence of exon 2 and loss of EGR1 expression in the Egr1d/d mouse, respectively. Moreover, the Egr1d/d female exhibits overt reproductive phenotypes previously reported for the Egr1KO mouse. Therefore, studies described in this short technical report underscore the potential utility of the murine Egr1 floxed allele to further resolve EGR1 function at a tissue- and/or cell-type-specific level.

Single-cell RNA-seq with spatial transcriptomics to create an atlas of human diabetic kidney disease

Diabetic kidney disease (DKD) develops in ~40% of patients with diabetes and is the leading cause of chronic kidney disease worldwide. We used single-cell RNA-sequencing and spatial transcriptomic analyses of kidney specimens from patients with DKD. Unsupervised clustering revealed distinct cell clusters, including epithelial cells and fibroblasts. We also identified differentially expressed genes (DEGs) and assessed enrichment, and cell-cell interactions. Specific enrichment of DKD was evident in venous endothelial cells (VECs) and fibroblasts with elevated CCL19 expression. The DEGs in most kidney parenchymal cells in DKD were primarily enriched in inflammatory signaling pathways. Intercellular crosstalk revealed that most cell interactions in DKD are associated with chemokines. Spatial transcriptomics revealed that VECs co-localized with fibroblasts, with most immune cells being enriched in areas of renal fibrosis. These results provided insight into the cell populations, intercellular interactions, and signaling pathways underlying the pathogenesis and potential targets for treating DKD.

Analysis of Lin28B Promoter Activity and Screening of Related Transcription Factors in Dolang Sheep

The Lin28B gene is involved in the initiation of puberty, but its regulatory mechanisms remain unclear. Therefore, in this study, we aimed to study the regulatory mechanism of the Lin28B promoter by cloning the Lin28B proximal promoter for bioinformatic analysis. Next, a series of deletion vectors were constructed based on the bioinformatic analysis results for dual-fluorescein activity detection. The transcriptional regulation mechanism of the Lin28B promoter region was analyzed by detecting mutations in transcription factor-binding sites and overexpression of transcription factors. The dual-luciferase assay showed that the Lin28B promoter region -837 to -338 bp had the highest transcriptional activity, and the transcriptional activity of the Lin28B transcriptional regulatory region decreased significantly after Egr1 and SP1 mutations. Overexpression of the Egr1 transcription factor significantly enhanced the transcription of Lin28B, and the results indicated that Egr1 and SP1 play important roles in regulating Lin28B. These results provide a theoretical basis for further research on the transcriptional regulation of sheep Lin28B during puberty initiation.

Activating Transcription Factor 3 Stimulates Follicle-Stimulating Hormone-β Expression In Vitro But Is Dispensable for Follicle-Stimulating Hormone Production in Murine Gonadotropes In Vivo

Follicle-stimulating hormone (FSH), a dimeric glycoprotein produced by pituitary gonadotrope cells, regulates spermatogenesis in males and ovarian follicle growth in females. Hypothalamic gonadotropin-releasing hormone (GnRH) stimulates FSHβ subunit gene (Fshb) transcription, though the underlying mechanisms are poorly understood. To address this gap in knowledge, we examined changes in pituitary gene expression in GnRH-deficient mice (hpg) treated with a regimen of exogenous GnRH that increases pituitary Fshb but not luteinizing hormone β (Lhb) messenger RNA levels. Activating transcription factor 3 (Atf3) was among the most upregulated genes. Activating transcription factor 3 (ATF3) can heterodimerize with members of the activator protein 1 family to regulate gene transcription. Co-expression of ATF3 with JunB stimulated murine Fshb, but not Lhb, promoter-reporter activity in homologous LβT2b cells. ATF3 also synergized with a constitutively active activin type I receptor to increase endogenous Fshb expression in these cells. Nevertheless, FSH production was intact in gonadotrope-specific Atf3 knockout [conditional knockout (cKO)] mice. Ovarian follicle development, ovulation, and litter sizes were equivalent between cKOs and controls. Testis weights and sperm counts did not differ between genotypes. Following gonadectomy, increases in LH secretion were enhanced in cKO animals. Though FSH levels did not differ between genotypes, post-gonadectomy increases in pituitary Fshb and gonadotropin α subunit expression were more pronounced in cKO than control mice. These data indicate that ATF3 can selectively stimulate Fshb expression in vitro but is not required for FSH production in vivo.

Models of Congenital Adrenal Hyperplasia for Gene Therapies Testing

The adrenal glands are important endocrine organs that play a major role in the stress response. Some adrenal glands abnormalities are treated with hormone replacement therapy, which does not address physiological requirements. Modern technologies make it possible to develop gene therapy drugs that can completely cure diseases caused by mutations in specific genes. Congenital adrenal hyperplasia (CAH) is an example of such a potentially treatable monogenic disease. CAH is an autosomal recessive inherited disease with an overall incidence of 1:9500–1:20,000 newborns. To date, there are several promising drugs for CAH gene therapy. At the same time, it remains unclear how new approaches can be tested, as there are no models for this disease. The present review focuses on modern models for inherited adrenal gland insufficiency and their detailed characterization. In addition, the advantages and disadvantages of various pathological models are discussed, and ways of further development are suggested.

Analysis of Methylation and mRNA Expression of Lin28B Gene Promoter Region in the Hypothalamus of Dolang Sheep During Pubertal Initiation

Lin28B plays an important role in puberty initiation in sheep. This study aimed to discuss the correlation between different growth periods and the methylation status of cytosine-guanine dinucleotide (CpG) islands in the promoter region of the Lin28B gene in the Dolang sheep's hypothalamus. In this study, the sequence of the Lin28B gene promoter region in Dolang sheep was obtained by cloning and sequencing, and methyl groups of the CpG island of the Lin28B gene promoter in the hypothalamus were detected by bisulfite sequencing PCR during the three periods of prepuberty, adolescence, and postpuberty in Dolang sheep. Lin28B expression in the Dolang sheep's hypothalamus was detected by fluorescence quantitative PCR at three stages: prepuberty, puberty, and postpuberty. In this experiment, the 2993-bp Lin28B promoter region was obtained, and it was predicted that there was a CpG island containing 15 transcription factor binding sites and 12 CpG sites, which may play a role in gene expression regulation. Overall, methylation levels increased from prepuberty to postpuberty, while Lin28B expression levels decreased, indicating that Lin28B expression was negatively correlated with promoter methylation levels. Variance analysis showed significant differences in the methylation status of CpG5, CpG7, and CpG9 between pre- and postpuberty (p < 0.05). Our data show that Lin28B expression is increased by demethylation of promoter CpG islands, with CpG5, CpG7, and CpG9 implicated as critical regulatory sites.

Glucose Homeostasis and Pancreatic Islet Size Are Regulated by the Transcription Factors Elk-1 and Egr-1 and the Protein Phosphatase Calcineurin

Pancreatic β-cells synthesize and secrete insulin. A key feature of diabetes mellitus is the loss of these cells. A decrease in the number of β-cells results in decreased biosynthesis of insulin. Increasing the number of β-cells should restore adequate insulin biosynthesis leading to adequate insulin secretion. Therefore, identifying proteins that regulate the number of β-cells is a high priority in diabetes research. In this review article, we summerize the results of three sophisticated transgenic mouse models showing that the transcription factors Elk-1 and Egr-1 and the Ca²⁺/calmodulin-regulated protein phosphatase calcineurin control the formation of sufficiently large pancreatic islets. Impairment of the biological activity of Egr-1 and Elk-1 in pancreatic β-cells leads to glucose intolerance and dysregulation of glucose homeostasis, the process that maintains glucose concentration in the blood within a narrow range. Transgenic mice expressing an activated calcineurin mutant also had smaller islets and showed hyperglycemia. Calcineurin induces dephosphorylation of Elk-1 which subsequently impairs Egr-1 biosynthesis and the biological functions of Elk-1 and Egr-1 to regulate islet size and glucose homeostasis.

Age-related changes in Folliculogenesis and potential modifiers to improve fertility outcomes - A narrative review

Reproductive aging is characterized by a decline in oocyte quantity and quality, which is directly associated with a decline in reproductive potential, as well as poorer reproductive success and obstetrical outcomes. As women delay childbearing, understanding the mechanisms of ovarian aging and follicular depletion have become increasingly more relevant. Age-related meiotic errors in oocytes are well established. In addition, it is also important to understand how intraovarian regulators change with aging and how certain treatments can mitigate the impact of aging. Individual studies have demonstrated that reproductive pathways involving antimullerian hormone (AMH), vascular endothelial growth factor (VEGF), neurotropins, insulin-like growth factor 1 (IGF1), and mitochondrial function are pivotal for healthy oocyte and cumulus cell development and are altered with increasing age. We provide a comprehensive review of these individual studies and explain how these factors change in oocytes, cumulus cells, and follicular fluid. We also summarize how modifiers of folliculogenesis, such as vitamin D, coenzyme Q, and dehydroepiandrosterone (DHEA) may be used to potentially overcome age-related changes and enhance fertility outcomes of aged follicles, as evidenced by human and rodent studies.

Integrative Analysis of miRNA-mRNA in Ovarian Granulosa Cells Treated with Kisspeptin in Tan Sheep

Kisspeptin is a peptide hormone encoded by the kiss-1 gene that regulates animal reproduction. Our studies revealed that kisspeptin can regulate steroid hormone production and promote cell proliferation in ovarian granulosa cells of Tan sheep, but the mechanism has not yet been fully understood. We speculated that kisspeptin might promote steroid hormone production and cell proliferation by mediating the expression of specific miRNA and mRNA in granulosa cells. Accordingly, after granulosa cells were treated with kisspeptin, the RNA of cells was extracted to construct a cDNA library, and miRNA-mRNA sequencing was performed. Results showed that 1303 expressed genes and 605 expressed miRNAs were identified. Furthermore, eight differentially expressed miRNAs were found, and their target genes were significantly enriched in progesterone synthesis/metabolism, hormone biosynthesis, ovulation cycle, and steroid metabolism regulation. Meanwhile, mRNA was significantly enriched in steroid biosynthesis, IL-17 signaling pathway, and GnRH signaling pathway. Integrative analysis of miRNA-mRNA revealed that the significantly different oar-let-7b targets eight genes, of which EGR1 (early growth response-1) might play a significant role in regulating the function of granulosa cells, and miR-10a regulates lipid metabolism and steroid hormone synthesis by targeting HNRNPD. Additionally, PPI analysis revealed genes that are not miRNA targets but crucial to other biological processes in granulosa cells, implying that kisspeptin may also indirectly regulate granulosa cell function by these pathways. The findings of this work may help understand the molecular mechanism of kisspeptin regulating steroid hormone secretion, cell proliferation, and other physiological functions in ovarian granulosa cells of Tan sheep.

Molecular Regulators of Embryonic Diapause and Cancer Diapause-like State

Embryonic diapause is an enigmatic state of dormancy that interrupts the normally tight connection between developmental stages and time. This reproductive strategy and state of suspended development occurs in mice, bears, roe deer, and over 130 other mammals and favors the survival of newborns. Diapause arrests the embryo at the blastocyst stage, delaying the post-implantation development of the embryo. This months-long quiescence is reversible, in contrast to senescence that occurs in aging stem cells. Recent studies have revealed critical regulators of diapause. These findings are important since defects in the diapause state can cause a lack of regeneration and control of normal growth. Controlling this state may also have therapeutic applications since recent findings suggest that radiation and chemotherapy may lead some cancer cells to a protective diapause-like, reversible state. Interestingly, recent studies have shown the metabolic regulation of epigenetic modifications and the role of microRNAs in embryonic diapause. In this review, we discuss the molecular mechanism of diapause induction.

Early growth response 1 transcription factor is essential for the pathogenic properties of human endometriotic epithelial cells

Although a non-malignant gynecological disorder, endometriosis displays some pathogenic features of malignancy, such as cell proliferation, migration, invasion and adaptation to hypoxia. Current treatments of endometriosis include pharmacotherapy and/or surgery, which are of limited efficacy and often associated with adverse side effects. Therefore, to develop more effective therapies to treat this disease, a broader understanding of the underlying molecular mechanisms that underpin endometriosis needs to be attained. Using immortalized human endometriotic epithelial and stromal cell lines, we demonstrate that the early growth response 1 (EGR1) transcription factor is essential for cell proliferation, migration and invasion, which represent some of the pathogenic properties of endometriotic cells. Genome-wide transcriptomics identified an EGR1-dependent transcriptome in human endometriotic epithelial cells that potentially encodes a diverse spectrum of proteins that are known to be involved in tissue pathologies. To underscore the utility of this transcriptomic data set, we demonstrate that carbonic anhydrase 9 (CA9), a homeostatic regulator of intracellular pH, is not only a molecular target of EGR1 but is also important for maintaining many of the cellular properties of human endometriotic epithelial cells that are also ascribed to EGR1. Considering therapeutic intervention strategies are actively being developed for EGR1 and CAIX in the treatment of other pathologies, we believe EGR1 and its transcriptome (which includes CA9) will offer not only a new conceptual framework to advance our understanding of endometriosis but will also furnish new molecular vulnerabilities to be leveraged as potential therapeutic options in the future treatment of endometriosis.

Bivalent-histone-marked immediate-early gene regulation is vital for VEGF-responsive angiogenesis

Endothelial cells (ECs) are phenotypically heterogeneous, mainly due to their dynamic response to the tissue microenvironment. Vascular endothelial cell growth factor (VEGF), the best-known angiogenic factor, activates calcium-nuclear factor of activated T cells (NFAT) signaling following acute angiogenic gene transcription. Here, we evaluate the global mapping of VEGF-mediated dynamic transcriptional events, focusing on major histone-code profiles using chromatin immunoprecipitation sequencing (ChIP-seq). Remarkably, the gene loci of immediate-early angiogenic transcription factors (TFs) exclusively acquire bivalent H3K4me3-H3K27me3 double-positive histone marks after the VEGF stimulus. Moreover, NFAT-associated Pax transactivation domain-interacting protein (PTIP) directs bivalently marked TF genes transcription through a limited polymerase II running. The non-canonical polycomb1 variant PRC1.3 specifically binds to and allows the transactivation of PRC2-enriched bivalent angiogenic TFs until conventional PRC1-mediated gene silencing is achieved. Knockdown of these genes abrogates post-natal aberrant neovessel formation via the selective inhibition of indispensable bivalent angiogenic TF gene transcription. Collectively, the reported dynamic histone mark landscape may uncover the importance of immediate-early genes and the development of advanced anti-angiogenic strategies.

Deletion of Gαq/11 or Gαs Proteins in Gonadotropes Differentially Affects Gonadotropin Production and Secretion in Mice

Gonadotropin-releasing hormone (GnRH) regulates gonadal function via its stimulatory effects on gonadotropin production by pituitary gonadotrope cells. GnRH is released from the hypothalamus in pulses and GnRH pulse frequency differentially regulates follicle-stimulating hormone (FSH) and luteinizing hormone (LH) synthesis and secretion. The GnRH receptor (GnRHR) is a G protein-coupled receptor that canonically activates Gα q/11-dependent signaling on ligand binding. However, the receptor can also couple to Gα s and in vitro data suggest that toggling between different G proteins may contribute to GnRH pulse frequency decoding. For example, as we show here, knockdown of Gα s impairs GnRH-stimulated FSH synthesis at low- but not high-pulse frequency in a model gonadotrope-derived cell line. We next used a Cre-lox conditional knockout approach to interrogate the relative roles of Gα q/11 and Gα s proteins in gonadotrope function in mice. Gonadotrope-specific Gα q/11 knockouts exhibit hypogonadotropic hypogonadism and infertility, akin to the phenotypes seen in GnRH- or GnRHR-deficient mice. In contrast, under standard conditions, gonadotrope-specific Gα s knockouts produce gonadotropins at normal levels and are fertile. However, the LH surge amplitude is blunted in Gα s knockout females and postgonadectomy increases in FSH and LH are reduced both in males and females. These data suggest that GnRH may signal principally via Gα q/11 to stimulate gonadotropin production, but that Gα s plays important roles in gonadotrope function in vivo when GnRH secretion is enhanced.

ADAMTS-1: a novel target gene of an estrogen-induced transcription factor, EGR1, critical for embryo implantation in the mouse uterus

BACKGROUND

Recently, we demonstrated that estrogen (E₂) induces early growth response 1 (Egr1) to mediate its actions on the uterine epithelium by controlling progesterone receptor signaling for successful embryo implantation. EGR1 is a transcription factor that regulates the spectrum of target genes in many different tissues, including the uterus. E₂-induced EGR1 regulates a set of genes involved in epithelial cell remodeling during embryo implantation in the uterus. However, only few target genes of EGR1 in the uterus have been identified.

RESULT

The expression of ADAM metallopeptidase with thrombospondin type 1 motif 1 (Adamts-1) was significantly downregulated in the uteri of E₂-treated ovariectomized (OVX) Egr1(-/-) mice. Immunostaining of ADAMTS-1 revealed its exclusive expression in the uterine epithelium of OVX wild-type but not Egr1(-/-) mice treated with E₂. The expression profiles of Adamts-1 and Egr1 were similar in the uteri of E₂-treated OVX mice at various time points tested. Pre-treatment with ICI 182, 780, a nuclear estrogen receptor (ER) antagonist, effectively inhibited the E₂-dependent induction of Egr1 and Adamts-1. Pharmacologic inhibition of E₂-induced ERK1/2 or p38 phosphorylation interfered with the induction of EGR1 and ADAMTS-1. Furthermore, ADAMTS-1, as well as EGR1, was induced in stroma cells surrounding the implanting blastocyst during embryo implantation. Transient transfection with EGR1 expression vectors significantly induced the expression of ADAMTS-1. Luciferase activity of the Adamts-1 promoter containing EGR1 binding sites (EBSs) was increased by EGR1 in a dose-dependent manner, suggesting functional regulation of Adamts-1 transcription by EGR1. Site-directed mutagenesis of EBS on the Adamts-1 promoter demonstrated that EGR1 directly binds to the EBS at -1151/-1134 among four putative EBSs.

CONCLUSIONS

Collectively, we have demonstrated that Adamts-1 is a novel target gene of E₂-ER-MAPK-EGR1, which is critical for embryo implantation in the mouse uterus during early pregnancy.

Chromatin-embedded reporter genes: Quantification of stimulus-induced gene transcription

Receptors and ion channels expressed on the cell surface ensure proper communication between the cells and the environment. In multicellular organism, stimulus-regulated gene transcription is the basis for communication with the environment allowing individual cells to respond to stimuli such as nutrients, chemical stressors and signaling molecules released by other cells of the organism. Hormones, cytokines, and mitogens bind to receptors and ion channels and induce intracellular signaling cascades involving second messengers, kinases, phosphatases, and changes in the concentration of particular ions. Ultimately, the signaling cascades reach the nucleus. Transcription factors are activated that respond to cellular stimulation and induce changes in gene transcription. Investigating stimulus-transcription coupling combines cell biology with genetics. In this review, we discuss the molecular biology of stimulus-induced transcriptional activators and their responsiveness to extracellular and intracellular signaling molecules and to epigenetic regulators. Stimulus-induced gene expression is measured by several methods, including detection of nuclear translocation of transcription factors, phosphorylation or DNA binding. In this article, we emphasize that the most reliable method to directly measure transcriptional activation involves the use of chromatin-embedded reporter genes.

Advances in the Regulation of Mammalian Follicle-Stimulating Hormone Secretion

Simple Summary

The reproduction of mammals is regulated by the hypothalamic-pituitary-gonadal axis. Follicle stimulating hormone, as one of the gonadotropins secreted by the pituitary gland, plays an immeasurable role. This article mainly reviews the molecular basis and classical signaling pathways that regulate the synthesis and secretion of follicle stimulating hormone, and summarizes its internal molecular mechanism, which provides a certain theoretical basis for the research of mammalian reproduction regulation and the application of follicle stimulating hormone in production practice.

Abstract

Mammalian reproduction is mainly driven and regulated by the hypothalamic-pituitary-gonadal (HPG) axis. Follicle-stimulating hormone (FSH), which is synthesized and secreted by the anterior pituitary gland, is a key regulator that ultimately affects animal fertility. As a dimeric glycoprotein hormone, the biological specificity of FSH is mainly determined by the β subunit. As research techniques are being continuously innovated, studies are exploring the underlying molecular mechanism regulating the secretion of mammalian FSH. This article will review the current knowledge on the molecular mechanisms and signaling pathways systematically regulating FSH synthesis and will present the latest hypothesis about the nuclear cross-talk among the various endocrine-induced pathways for transcriptional regulation of the FSH β subunit. This article will provide novel ideas and potential targets for the improved use of FSH in livestock breeding and therapeutic development.

Two transcriptionally distinct pathways drive female development in a reptile with both genetic and temperature dependent sex determination

How temperature determines sex remains unknown. A recent hypothesis proposes that conserved cellular mechanisms (calcium and redox; 'CaRe' status) sense temperature and identify genes and regulatory pathways likely to be involved in driving sexual development. We take advantage of the unique sex determining system of the model organism, Pogona vitticeps, to assess predictions of this hypothesis. P. vitticeps has ZZ male: ZW female sex chromosomes whose influence can be overridden in genetic males by high temperatures, causing male-to-female sex reversal. We compare a developmental transcriptome series of ZWf females and temperature sex reversed ZZf females. We demonstrate that early developmental cascades differ dramatically between genetically driven and thermally driven females, later converging to produce a common outcome (ovaries). We show that genes proposed as regulators of thermosensitive sex determination play a role in temperature sex reversal. Our study greatly advances the search for the mechanisms by which temperature determines sex.

Altered light induced EGR1 expression in the SCN of PACAP deficient mice

The brain’s biological clock is located in the suprachiasmatic nucleus (SCN) of the hypothalamus and generates circadian rhythms in physiology and behavior. The circadian clock needs daily adjustment by light to stay synchronized (entrained) with the astronomical 24 h light/dark cycle. Light entrainment occurs via melanopsin expressing retinal ganglion cells (mRGCs) and two neurotransmitters of the retinohypothalamic tract (RHT), PACAP and glutamate, which transmit light information to the SCN neurons. In SCN neurons, light signaling involves the immediate-early genes Fos, Egr1 and the clock genes Per1 and Per2. In this study, we used PACAP deficient mice to evaluate PACAP’s role in light induced gene expression of EGR1 in SCN neurons during early (ZT17) and late (ZT23) subjective night at high (300 lux) and low (10 lux) white light exposure. We found significantly lower levels of both EGR1 mRNA and protein in the SCN in PACAP deficient mice compared to wild type mice at early subjective night (ZT17) exposed to low but not high light intensity. No difference was found between the two genotypes at late night (ZT23) at neither light intensities. In conclusion, light mediated EGR1 induction in SCN neurons at early night at low light intensities is dependent of PACAP signaling. A role of PACAP in shaping synaptic plasticity during light stimulation at night is discussed.

Early growth response gene mediates in VEGF and FGF signaling as dissected by CRISPR in corpus luteum of water buffalo

The EGR family comprises of EGR 1, EGR 2, EGR 3 and EGR 4 which are involved in the transactivation of several genes. A broad range of extracellular stimuli by growth factors is capable of activating EGR mediated transactivation of genes involved in angiogenesis and cell proliferation. However, their role in controlling VEGF A and FGF 2 signaling in the CL of water buffalo is not known. The present study was conducted to understand the role of EGR mediated regulation of VEGF A and FGF 2 signaling in buffalo luteal cells. Towards this goal, luteal cells were cultured and treated with VEGF A and FGF 2 and the mRNA expression pattern of EGR family members were documented. The EGR 1 message was found to be up-regulated in luteal cells of buffalo at 72 hours of culture. The functional validation of EGR 1 gene was accomplished by knocking out (KO) of EGR 1 in cultured luteal cells by CRISPR/Cas9 mediated gene editing technology. The EGR 1 KO cells were then cultured and stimulated with VEGF A and FGF 2. It was observed that VEGF A and FGF 2 induced angiogenesis, cell proliferation and steroidogenesis in wild type luteal cells, whereas the response of the growth factors was attenuated in the EGR 1 KO cells. Taken together our study provides evidence convincingly that both VEGF and FGF mediate their biological action through a common intermediate, EGR 1, to regulate corpus luteum function of buffalo.

Mitochondrial pyruvate and fatty acid flux modulate MICU1-dependent control of MCU activity

The tricarboxylic acid (TCA) cycle converts the end products of glycolysis and fatty acid β-oxidation into the reducing equivalents NADH and FADH2 Although mitochondrial matrix uptake of Ca2+ enhances ATP production, it remains unclear whether deprivation of mitochondrial TCA substrates alters mitochondrial Ca2+ flux. We investigated the effect of TCA cycle substrates on MCU-mediated mitochondrial matrix uptake of Ca2+, mitochondrial bioenergetics, and autophagic flux. Inhibition of glycolysis, mitochondrial pyruvate transport, or mitochondrial fatty acid transport triggered expression of the MCU gatekeeper MICU1 but not the MCU core subunit. Knockdown of mitochondrial pyruvate carrier (MPC) isoforms or expression of the dominant negative mutant MPC1R97W resulted in increased MICU1 protein abundance and inhibition of MCU-mediated mitochondrial matrix uptake of Ca2+ We also found that genetic ablation of MPC1 in hepatocytes and mouse embryonic fibroblasts resulted in reduced resting matrix Ca2+, likely because of increased MICU1 expression, but resulted in changes in mitochondrial morphology. TCA cycle substrate-dependent MICU1 expression was mediated by the transcription factor early growth response 1 (EGR1). Blocking mitochondrial pyruvate or fatty acid flux was linked to increased autophagy marker abundance. These studies reveal a mechanism that controls the MCU-mediated Ca2+ flux machinery and that depends on TCA cycle substrate availability. This mechanism generates a metabolic homeostatic circuit that protects cells from bioenergetic crisis and mitochondrial Ca2+ overload during periods of nutrient stress.

Clinicopathological analysis of 250 cases of pituitary adenoma under the new WHO classification

Pituitary adenomas (PAs) are a common subtype of intracranial tumors. The aim of the present study was to analyse the clinical and pathological features of different types of pituitary adenomas (PAs) according to the 2017 World Health Organisation Endocrine Organ Tumor Classification guidelines. The clinical data of 250 patients with PAs were collected and analysed. Differences in the incidence of invasion, recurrence and apoplexy in patients between high- and low-risk PAs were compared, as were differences in the Ki-67 index between invasive and non-invasive PAs and between recurrent PAs and non-recurrent PAs. Of the 250 cases, 45 cases were diagnosed as somatotroph adenomas, 26 cases as lactotroph adenomas, 1 case as thyrotroph adenoma, 61 cases as corticotroph adenomas, 93 cases as gonadotropin adenomas, 15 cases as null cell adenomas and 9 cases as plurihormonal adenomas. There were 5 types of high-risk pituitary adenoma identified: 17 cases of sparsely granulated somatotroph adenoma, 11 cases of lactotroph adenoma in men, 3 cases of plurihormonal PIT-1 positive adenoma and 42 cases of silent corticotroph adenoma. Crooke's cell adenoma was not identified. High-risk PAs had significantly higher rates of invasion, recurrence and apoplexy compared with that in low-risk types (P<0.001). Invasive PAs had a significantly higher Ki-67 index compared with that in non-invasive PAs (3.5±1.8 vs. 2.8±1.3; P<0.01). Recurrent PAs had a significantly higher Ki-67 index compared with that in non-recurrent PAs (3.9±1.9 vs. 2.8±1.3; P<0.001). According to the 2017 classification criteria, patients most frequently had gonadotrophin cell adenomas, followed by corticotroph adenomas and the proportion of null cell adenomas was reduced. Differences were noted in the proliferation, recurrence and apoplexy characteristics of high-risk PAs and low-risk PAs. The invasion and recurrence of PAs were found to be related to the Ki-67 index.

Plasticity of Anterior Pituitary Gonadotrope Cells Facilitates the Pre-Ovulatory LH Surge

Gonadotropes cells located in the anterior pituitary gland are critical for reproductive fitness. A rapid surge in the serum concentration of luteinizing hormone (LH) secreted by anterior pituitary gonadotropes is essential for stimulating ovulation and is thus required for a successful pregnancy. To meet the requirements to mount the LH surge, gonadotrope cells display plasticity at the cellular, molecular and morphological level. First, gonadotrope cells heighten their sensitivity to an increasing frequency of hypothalamic GnRH pulses by dynamically elevating the expression of the GnRH receptor (GnRHR). Following ligand binding, GnRH initiates highly organized intracellular signaling cascades that ultimately promote the synthesis of LH and the trafficking of LH vesicles to the cell periphery. Lastly, gonadotrope cells display morphological plasticity, where there is directed mobilization of cytoskeletal processes towards vascular elements to facilitate rapid LH secretion into peripheral circulation. This mini review discusses the functional and organizational plasticity in gonadotrope cells including changes in sensitivity to GnRH, composition of the GnRHR signaling platform within the plasma membrane, and changes in cellular morphology. Ultimately, multimodal plasticity changes elicited by gonadotropes are critical for the generation of the LH surge, which is required for ovulation.

Divergent expression patterns of pituitary gonadotropin subunit and GnRH receptor genes to continuous GnRH in vitro and in vivo

Continuous, as opposed to pulsatile, delivery of hypothalamic gonadotropin-releasing hormone (GnRH) leads to a marked decrease in secretion of pituitary gonadotropins LH and FSH and impairment of reproductive function. Here we studied the expression profile of gonadotropin subunit and GnRH receptor genes in rat pituitary in vitro and in vivo to clarify their expression profiles in the absence and continuous presence of GnRH. Culturing of pituitary cells in GnRH-free conditions downregulated Fshb, Cga, and Gnrhr expression, whereas continuous treatment with GnRH agonists upregulated Cga expression progressively and Gnrhr and Fshb expression transiently, accompanied by a prolonged blockade of Fshb but not Gnrhr expression. In contrast, Lhb expression was relatively insensitive to loss of endogenous GnRH and continuous treatment with GnRH, probably reflecting the status of Egr1 and Nr5a1 expression. Similar patterns of responses were observed in vivo after administration of a GnRH agonist. However, continuous treatment with GnRH stimulated LH secretion in vitro and in vivo, leading to decrease in LH cell content despite high basal Lhb expression. These data suggest that blockade of Fshb expression and depletion of the LH secretory pool are two major factors accounting for weakening of the gonadotroph secretory function during continuous GnRH treatment.

The anti-androgenic effects of cypermethrin mediated by non-classical testosterone pathway activation of mitogen-activated protein kinase cascade in mouse Sertoli cells

Previous studies have demonstrated that the anti-androgenic effects of cypermethrin (CYP) are associated with testosterone (T) - related signaling pathway. This study was to investigate the effects of CYP on mouse Sertoli cells (TM4) and clarify whether the mechanisms were mediated by non-classical T signaling pathway activating mitogen-activated protein kinase (MAPK) cascade. The Cell Counting Kit 8 (CCK8) and Real-Time Cell Analysis iCELLigence (RTCA-iCELLigence) system were performed to detect the effects of 10 μM, 20 μM, 40 μM and 80 μM CYP on the viability and proliferation of TM4. The mammalian two hybrid assay, quantitative Real-Time PCR (qRT-PCR) and western blot were conducted to analyze the key genes and proteins involved in T-mediated MAPK signaling pathway. CYP was found to inhibit the viability and proliferation of TM4. Additionally, CYP disturbed the functions of Sertoli cells by inhibiting inhibin B (INH B) expression and facilitating androgen binding protein (ABP) and transferrin (TF) expression. Moreover, CYP suppressed the interaction of AR and Src kinase and inhibited androgen-mediated phosphorylation of Src, epidermal growth factor receptor (EGFR), extracellular-regulated kinase1/2 (ERK1/2) and transcription factor cAMP response element binding protein (CREB). Furthermore, the androgen-induced mRNA and protein expression of CREB-regulated gene early growth response factor (Egr1) decreased after treated with CYP. It is indicated that CYP inhibits the viability and proliferation of Sertoli cells and non-classical T signaling pathway activation of MAPK cascade is involved in anti-androgenic effect of CYP. This study provides a novel insight into the CYP-induced reproductive toxicity.

Single-molecule DNA unzipping reveals asymmetric modulation of a transcription factor by its binding site sequence and context

Most functional transcription factor (TF) binding sites deviate from their ‘consensus’ recognition motif, although their sites and flanking sequences are often conserved across species. Here, we used single-molecule DNA unzipping with optical tweezers to study how Egr-1, a TF harboring three zinc fingers (ZF1, ZF2 and ZF3), is modulated by the sequence and context of its functional sites in the Lhb gene promoter. We find that both the core 9 bp bound to Egr-1 in each of the sites, and the base pairs flanking them, modulate the affinity and structure of the protein–DNA complex. The effect of the flanking sequences is asymmetric, with a stronger effect for the sequence flanking ZF3. Characterization of the dissociation time of Egr-1 revealed that a local, mechanical perturbation of the interactions of ZF3 destabilizes the complex more effectively than a perturbation of the ZF1 interactions. Our results reveal a novel role for ZF3 in the interaction of Egr-1 with other proteins and the DNA, providing insight on the regulation of Lhb and other genes by Egr-1. Moreover, our findings reveal the potential of small changes in DNA sequence to alter transcriptional regulation, and may shed light on the organization of regulatory elements at promoters.

Invited Review: Pathology of pituitary neuroendocrine tumours: present status, modern diagnostic approach, controversies and future perspectives from a neuropathological and clinical standpoint

Neuroendocrine tumours of the adenohypophysis have traditionally been designated as pituitary adenomas to underline their usually indolent growth and lack of metastatic potential. However, they may demonstrate a huge spectrum of growth patterns and endocrine disturbances, some of them significantly affecting health and quality of life. To predict tumour growth, risk of postoperative recurrence and response to medical therapy in patients with pituitary neuroendocrine tumours is challenging. A thorough histopathological and immunohistochemical diagnostic work-up is an obligatory part of a multidisciplinary effort to precisely define the tumour type and assess prognostic and predictive factors on an individual basis. In this review, we have summarized the current status in the pathology in pituitary neuroendocrine tumours based on the selection of references from the PubMed database. We have presented possible diagnostic approaches according to the current pituitary cell lineage-based classification. The importance of recognizing histological subtypes with potentially aggressive behaviour and identification of prognostic and predictive tissue biomarkers have been highlighted. Controversies related to particular subtypes of pituitary tumours and a still limited prognostic impact of the current classification indicate the need for further refinement. Multidisciplinary approach including clinical, pathological and molecular genetic characterization will be essential for improved personalized therapy and the search for novel therapeutic targets in patients with pituitary neuroendocrine tumours.

DNA Methylation Readers and Cancer: Mechanistic and Therapeutic Applications

DNA methylation is a major epigenetic process that regulates chromatin structure which causes transcriptional activation or repression of genes in a context-dependent manner. In general, DNA methylation takes place when methyl groups are added to the appropriate bases on the genome by the action of "writer" molecules known as DNA methyltransferases. How these methylation marks are read and interpreted into different functionalities represents one of the main mechanisms through which the genes are switched "ON" or "OFF" and typically involves different types of "reader" proteins that can recognize and bind to the methylated regions. A tightly balanced regulation exists between the "writers" and "readers" in order to mediate normal cellular functions. However, alterations in normal methylation pattern is a typical hallmark of cancer which alters the way methylation marks are written, read and interpreted in different disease states. This unique characteristic of DNA methylation "readers" has identified them as attractive therapeutic targets. In this review, we describe the current state of knowledge on the different classes of DNA methylation "readers" identified thus far along with their normal biological functions, describe how they are dysregulated in cancer, and discuss the various anti-cancer therapies that are currently being developed and evaluated for targeting these proteins.

Early growth response 1 transcriptionally primes the human endometrial stromal cell for decidualization

Mouse studies support a role for endometrial early growth response 1 (EGR1) in uterine receptivity and decidualization, which are processes controlled by estrogen and progesterone. However, the importance of this transcription factor in similar cellular processes in human is unclear. Analysis of clinical samples indicate that endometrial EGR1 levels are decreased in the endometrium of women with recurrent implantation failure, suggesting that tight control of EGR1 levels are necessary for normal endometrial function. Therefore, we used siRNA-mediated knockdown of EGR1 expression in cultured human endometrial stromal cells (hESCs) to assess the functional role of EGR1 in hESC decidualization. Protein expression studies revealed that EGR1 is highly expressed in pre-decidual hESCs. However, EGR1 protein levels rapidly decrease following administration of an established deciduogenic hormone stimulus containing estradiol, medroxyprogesterone acetate, and cyclic adenosine monophosphate. Intriguingly, EGR1 knockdown in pre-decidual hESCs blocks the ability of these cells to decidualize later, indicating that EGR1 is required to transcriptionally program pre-decidual hESCs for decidualization. Support for this proposal comes from the analysis of transcriptome and cistrome datasets, which shows that EGR1 target genes are primarily involved in transcriptional regulation, cell signaling, and proliferation. Collectively, our studies provide translational support for an evolutionary conserved role for human endometrial stromal EGR1 in the early events of pregnancy establishment.

Filtered reproductive long non-coding RNAs by genome-wide analyses of goat ovary at different estrus periods

Background

The goat is an important farm animal. Reproduction is an important process of goat farming. The ovary is the most important reproductive organ for goats. In recent years, an increasing number of long non-coding RNAs (lncRNAs) have been implicated in the regulation of mammal reproduction. However, there are few studies on the function of lncRNAs in reproduction, particularly lncRNAs in the ovary.

Results

The sequencing of goat ovaries generated 1,122,014,112 clean reads, and 4926 lncRNAs and 1454 TUCPs (transcripts of uncertain coding potential) were identified for further analysis by using the coding potential analysis software, CNCI, CPC and Pfam-sca. There were 115 /22 differential lncRNAs /TUCPs transcripts between the ovaries of the luteal phase and the follicular phase. We predicted the related genes of lncRNA /TUCP based on co-expression and co-localization methods. In total, 2584 /904 genes were predicted by co-expression, and 326/73 genes were predicted by co-localization. The functions of these genes were further analyzed with GO and KEGG analysis. The results showed that lncRNAs /TUCPs, which are highly expressed in goat ovaries in the luteal phase, are mainly associated with the synthesis of progesterone, and we filtered the lncRNAs /TUCPs, such as XR_001918177.1 and TUCP_001362, which may regulate the synthesis of progesterone; lncRNAs /TUCPs, which are highly expressed in goat ovaries in the follicular phase, are mainly associated with oogenesis and the maturation of oocytes, and we filtered the lncRNAs /TUCPs that may regulate the oogenesis and maturation of oocyte, such as XR_001917388.1 and TUCP_000849.

Conclusion

The present study provided the genome expression profile of lncRNAs /TUCPs in goat ovaries at different estrus periods and filtered the potential lncRNAs /TUCPs associated with goat reproduction. These results are helpful to further study the molecular mechanisms of goat reproduction.

Electronic supplementary material

The online version of this article (10.1186/s12864-018-5268-7) contains supplementary material, which is available to authorized users.

GnRH Transactivates Human AMH Receptor Gene via Egr1 and FOXO1 in Gonadotrope Cells

BACKGROUND/OBJECTIVES

Anti-Müllerian hormone (AMH) signaling is critical for sexual differentiation and gonadal function. AMH receptor type 2 (AMHR2) is expressed in extragonadal sites such as brain, and pituitary and emerging evidence indicates that AMH biological action is much broader than initially thought. We recently reported that AMH signaling enhances follicle-stimulating hormone synthesis in pituitary gonadotrope cells. However, mechanisms regulating AMHR2 expression in these extragonadal sites remain to be explored.

METHOD/RESULTS

Here, we demonstrated in perifused murine LβT2 gonadotrope cells that Amhr2 expression is differentially regulated by GnRH pulse frequency with an induction under high GnRH pulsatility. Furthermore, we showed that GnRH transactivates the human AMHR2 promoter in LβT2 cells. Successive deletions of the promoter revealed the importance of a short proximal region (-53/-37 bp) containing an Egr1 binding site. Using site-directed mutagenesis of Egr1 motif and siRNA mediated-knockdown of Egr1, we demonstrated that Egr1 mediates basal and GnRH-dependent activity of the promoter, identifying Egr1 as a new transcription factor controlling hAMHR2 expression. We also showed that SF1 and β-catenin are required for basal promoter activity and demonstrated that both factors contribute to the GnRH stimulatory effect, independently of their respective binding sites. Furthermore, using a constitutively active mutant of FOXO1, we identified FOXO1 as a negative regulator of basal and GnRH-dependent AMHR2 expression in gonadotrope cells.

CONCLUSIONS

This study identifies GnRH as a regulator of human AMHR2 expression, further highlighting the importance of AMH signaling in the regulation of gonadotrope function.

Bu-shen-zhu-yun decoction promotes synthesis and secretion of FSHβ and LHβ in anterior pituitary cells in vitro

Luteal phase defects (LPD) are an important etiology of infertility which has increased in recent years. Studies have shown that bu-shen-zhu-yun decoction (BSZY-D) can lower the expression of estrogen receptor and progesterone receptor, in rats endometrium of embryonic implantation period, which upregulated by mifepristone, and improve uterine receptivity. The aim of present study was to determine the effect of BSZY-D on the synthesis and secretion of gonadotropic hormones in the anterior pituitary cells of rats. Rats were treated with saline (control) or BSZY-D two times/day for three estrous cycles by gavage. The cerebrospinal fluid (CSF) were collected for further cell treatment. The components in BSZY-D, serum and CSF were analysed by High Performance Liquid Chromatography (HPLC). Cells were either pretreated with normal CSF or BSZY-D/CSF before being stimulated with or without cetrorelix. The mRNA and proteins levels of receptors, hormones, and transcription factors were detected by RT-PCR, western blot analysis and immunostaining. We show that non-toxic concentrations of cetrorelix, a GnRH antagonist, can reduce the mRNA and protein levels of GnRHR, LH, and FSH. This effect could be reversed by the addition of BSZY-D/CSF. We also show decreased mRNA and protein expression of transcription factors, such as CREB, and Egr-1 and secretory vescicles, including SNAP-25 and Munc-18 upon treatment with cetrorelix could be reversed post co-treatment with BSZY-D/CSF. These results indicate that BSZY-D/CSF treatment led to increased levels of GnRHR, transcription factors, and secretory vesicles leading to increased secretion of FSH and LH. Thus, BSZY-D presents a promising candidate to treat luteal phase defects and infertility.

Regulation of reproduction via tight control of gonadotropin hormone levels

Mammalian reproduction is controlled by the hypothalamic-pituitary-gonadal axis. GnRH from the hypothalamus regulates synthesis and secretion of gonadotropins, LH and FSH, which then control steroidogenesis and gametogenesis. In females, serum LH and FSH levels exhibit rhythmic changes throughout the menstrual or estrous cycle that are correlated with pulse frequency of GnRH. Lack of gonadotropins leads to infertility or amenorrhea. Dysfunctions in the tightly controlled ratio due to levels slightly outside the normal range occur in a larger number of women and are correlated with polycystic ovaries and premature ovarian failure. Since the etiology of these disorders is largely unknown, studies in cell and mouse models may provide novel candidates for investigations in human population. Hence, understanding the mechanisms whereby GnRH regulates gonadotropin hormone levels will provide insight into the physiology and pathophysiology of the reproductive system. This review discusses recent advances in our understanding of GnRH regulation of gonadotropin synthesis.

Gonadotropin regulation by pulsatile GnRH: Signaling and gene expression

The precise orchestration of hormonal regulation at all levels of the hypothalamic-pituitary-gonadal axis is essential for normal reproductive function and fertility. The pulsatile secretion of hypothalamic gonadotropin-releasing hormone (GnRH) stimulates the synthesis and release of follicle-stimulating hormone (FSH) and luteinizing hormone (LH) by pituitary gonadotropes. GnRH acts by binding to its high affinity seven-transmembrane receptor (GnRHR) on the cell surface of anterior pituitary gonadotropes. Different signaling cascades and transcriptional mechanisms are activated, depending on the variation in GnRH pulse frequency, to stimulate the synthesis and release of FSH and LH. While changes in GnRH pulse frequency may explain some of the differential regulation of FSH and LH, other factors, such as activin, inhibin and sex steroids, also contribute to gonadotropin production. In this review, we focus on the transcriptional regulation of the gonadotropin subunit genes and the signaling pathways activated by pulsatile GnRH.

GnRH Receptor Expression and Reproductive Function Depend on JUN in GnRH Receptor‒Expressing Cells

Gonadotropin-releasing hormone (GnRH) from the hypothalamus regulates synthesis and secretion of luteinizing hormone (LH) and follicle-stimulating hormone (FSH) from the anterior pituitary gonadotropes. LH and FSH are heterodimers composed of a common α-subunit and unique β-subunits, which provide biological specificity and are limiting components of mature hormone synthesis. Gonadotrope cells respond to GnRH via specific expression of the GnRH receptor (Gnrhr). GnRH induces the expression of gonadotropin genes and of the Gnrhr by activation of specific transcription factors. The JUN (c-Jun) transcription factor binds to AP-1 sites in the promoters of target genes and mediates induction of the FSHβ gene and of the Gnrhr in gonadotrope-derived cell lines. To analyze the role of JUN in reproductive function in vivo, we generated a mouse model that lacks JUN specifically in GnRH receptor‒expressing cells (conditional JUN knockout; JUN-cKO). JUN-cKO mice displayed profound reproductive anomalies such as reduced LH levels resulting in lower gonadal steroid levels, longer estrous cycles in females, and diminished sperm numbers in males. Unexpectedly, FSH levels were unchanged in these animals, whereas Gnrhr expression in the pituitary was reduced. Steroidogenic enzyme expression was reduced in the gonads of JUN-cKO mice, likely as a consequence of reduced LH levels. GnRH receptor‒driven Cre activity was detected in the hypothalamus but not in the GnRH neuron. Female, but not male, JUN-cKO mice exhibited reduced GnRH expression. Taken together, our results demonstrate that GnRH receptor‒expression levels depend on JUN and are critical for reproductive function.

Beta-Defensin 2 and 3 Promote Bacterial Clearance of Pseudomonas aeruginosa by Inhibiting Macrophage Autophagy through Downregulation of Early Growth Response Gene-1 and c-FOS

Beta-defensins 2 and 3 (BD2 and BD3) are inducible peptides present at the sites of infection, and they are well characterized for their antimicrobial activities and immune-regulatory functions. However, no study has thoroughly investigated their immunomodulatory effects on macrophage-mediated immune responses against Pseudomonas aeruginosa (PA). Here, we use THP-1 and RAW264.7 cell lines and demonstrate that BD2 and BD3 suppressed macrophage autophagy but enhanced the engulfment of PA and Zymosan bioparticles as well as the formation of phagolysosomes, using immunofluorescence staining and confocal microscopy. Plate count assay showed that macrophage-mediated phagocytosis and intracellular killing of PA were promoted by BD2 and BD3. Furthermore, microarray and real-time PCR showed that the expression of two genes, early growth response gene-1 (EGR1) and c-FOS, was attenuated by BD2 and BD3. Western blot revealed that BD2 and BD3 inhibited the expression and nuclear translocation of EGR1 and c-FOS. Knockdown of EGR1 and c-FOS by siRNA transfection suppressed macrophage autophagy before and after PA infection; while overexpression of these two transcription factors enhanced autophagy but reversed the role of BD2 and BD3 on macrophage-mediated PA eradication. Together, these results demonstrate a novel immune defense activity of BD2 and BD3, which promotes clearance of PA by inhibiting macrophage autophagy through downregulation of EGR1 and c-FOS.

Estrogen induces EGR1 to fine-tune its actions on uterine epithelium by controlling PR signaling for successful embryo implantation

The harmonized actions of ovarian E₂ and progesterone (P₄) regulate the proliferation and differentiation of uterine cells in a spatiotemporal manner. Imbalances between these hormones often lead to infertility and gynecologic diseases. Whereas numerous factors that are involved in P₄ signaling have been identified, few local factors that mediate E₂ actions in the uterus have been revealed. Here, we demonstrate that estrogen induces the transcription factor, early growth response 1 ( Egr1), to fine-tune its actions in uterine epithelial cells (ECs) that are responsible for uterine receptivity for embryo implantation. In the presence of exogenous gonadotrophins, ovulation, fertilization, and embryonic development normally occur in Egr1^-/- mice, but these animals experience the complete failure of embryo implantation with reduced artificial decidualization. Although serum levels of E₂ and P₄ were comparable between Egr1^+/+ and Egr1^-/- mice on d 4 of pregnancy, aberrantly reduced levels of progesterone receptor in Egr1^-/- uterine ECs caused enhanced E₂ activity and impaired P₄ response. Ultrastructural analyses revealed that Egr1^-/- ECs are not fully able to provide proper uterine receptivity. Uterine mRNA landscapes in Egr1^-/- mice revealed that EGR1 controls the expression of a subset of E₂-regulated genes. In addition, P₄ signaling was unable to modulate estrogen actions, including those that are involved in cell-cycle progression, in ECs that were deficient in EGR1. Furthermore, primary coculture of Egr1^-/- ECs with Egr1^+/+ stromal cells, and vice versa, supported the notion that Egr1 is required to modulate E₂ actions on ECs to prepare the uterine environment for embryo implantation. In contrast to its role in ECs, loss of Egr1 in stroma significantly reduced stromal cell proliferation. Collectively, our results demonstrate that E₂ induces EGR1 to streamline its actions for the preparation of uterine receptivity for embryo implantation in mice.-Kim, H.-R., Kim, Y. S., Yoon, J. A., Yang, S. C., Park, M., Seol, D.-W., Lyu, S. W., Jun, J. H., Lim, H. J., Lee, D. R., Song, H. Estrogen induces EGR1 to fine-tune its actions on uterine epithelium by controlling PR signaling for successful embryo implantation.

Loss of Egr1, a human del5q gene, accelerates BCR-ABL driven chronic myelogenous leukemia

There is substantial evidence that early growth response-1 (Egr1) gene, a zinc-finger transcription factor, behaves as a tumor suppressor in leukemia. This includes reports from this laboratory that constitutive Egr1 overrides leukemia conferred by deregulated c-Myc or E2F-1 in the M1 myeloid leukemic cell line by promoting differentiation. To investigate the effect of Egr1 on the initiation and progression of Chronic Myelogenous Leukemia (CML), lethally irradiated syngeneic wild type mice were reconstituted with bone marrow (BM) from either wild type or Egr1 null mice transduced with a 210-kD BCR-ABL-expressing MSCV-retrovirus (bone marrow transplantation {BMT}). Loss of Egr1 was observed to accelerate the development of BCR-ABL driven leukemia in recipient mice, resulting in the development of a more aggressive disease, a significantly shortened median survival time, and increased BCR-ABL expressing leukemic stem/progenitor cells (GFP+Lin-cKit+Sca+). Egr1 deficient progenitors expressing BCR-ABL exhibited decreased apoptosis, and increased cell viability and proliferation relative to WT counterparts. Secondary BMT of BCR-ABL BM revealed that loss of Egr1 resulted in enrichment of LSCs, consistent with shorter survival time and more aggressive disease of these mice compared to WT counterparts. Furthermore, serial re-plating colony assays indicated that loss of Egr1 increased self-renewal ability of BCR-ABL expressing BM. These novel findings on the tumor suppressor role of Egr1 in CML provide the impetus to study the effect of altering Egr1 expression in AML, where the overall five year survival rate remains low. The effect of loss of Egr1 in CML could reflect its established functions in normal hematopoiesis, maintaining quiescence of HSCs and driving terminal differentiation to the monocyte/macrophage lineage. Gain of function studies should validate these conclusions and provide further rationale for increased Egr1 as a therapeutic target in AML.

Regulation of Gene Transcription Following Stimulation of Transient Receptor Potential (TRP) Channels

Transient receptor potential (TRP) channels belong to a heterogeneous superfamily of cation channels that are involved in the regulation of numerous biological functions, including regulation of Ca²⁺ and glucose homeostasis, tumorigenesis, temperature, and pain sensation. To understand the functions of TRP channels, their associated intracellular signaling pathways and molecular targets have to be identified on the cellular level. Stimulation of TRP channels frequently induces an influx of Ca²⁺ ions into the cells and the subsequent activation of protein kinases. These intracellular signal transduction pathways ultimately induce changes in the gene expression pattern of the cells. Here, we review the effects of TRPC6, TRPM3, and TRPV1 channel stimulation on the activation of the stimulus-responsive transcription factors AP-1, CREB, Egr-1, Elk-1, and NFAT. Following activation, these transcription factors induce the transcription of delayed response genes. We propose that many biological functions of TRP channels can be explained by the activation of stimulus-responsive transcription factors and their delayed response genes. The proteins encoded by those delayed response genes may be responsible for the biochemical and physiological changes following TRP channel activation.

Inhibition of Early Growth Response 1 in the Hippocampus Alleviates Neuropathology and Improves Cognition in an Alzheimer Model with Plaques and Tangles

A sporadic form of Alzheimer disease (AD) and vascular dementia share many risk factors, and their pathogenic mechanisms are suggested to be related. Transcription factor early growth response 1 (Egr-1) regulates various vascular pathologies and is up-regulated in both AD brains and AD mouse models; however, its role in AD pathogenesis is unclear. Herein, we report that silencing of Egr-1 in the hippocampus by shRNA reduces tau phosphorylation, lowers amyloid-β (Aβ) pathology, and improves cognition in the 3xTg-AD mouse model. Egr-1 silencing does not affect levels of cyclin-dependent protein kinase 5 (Cdk5), glycogen synthase kinase 3β, protein phosphatase 1, or protein phosphatase 2A, but reduces p35 subunit of Cdk5. Egr-1 silencing also reduces levels of β-secretase 1 (BACE-1) and BACE-1-cleaved amyloid precursor protein (APP) metabolites (secreted APPβ, C99, Aβ40, and Aβ42) but has no effect on presenilin 1 and presenilin 2. In hippocampal primary neurons, Egr-1 binds to BACE-1 and p35 promoters, enhances tau phosphorylation, activates Cdk5 and BACE-1, and accelerates amyloidogenic APP processing. Blocking Cdk5 action blocks Egr-1-induced tau phosphorylation but has no effect on BACE-1 activation and amyloidogenic APP processing. Blocking BACE-1 action, on the other hand, blocks Egr-1-induced amyloidogenic APP processing but does not affect tau phosphorylation. Egr-1 regulates tau phosphorylation and Aβ synthesis in the brain by respectively controlling activities of Cdk5 and BACE-1, suggesting that Egr-1 is a potential therapeutic candidate for the treatment of AD.

Sequence variations of the EGR4 gene in Korean men with spermatogenesis impairment

Background

Egr4 is expressed in primary and secondary spermatocytes in adult mouse testes and has a crucial role in regulating germ cell maturation. The functional loss of Egr4 blocks spermatogenesis, significantly reducing the number of spermatozoa that are produced. In this study, we examined whether EGR4 variants are present in Korean men with impaired spermatogenesis.

Methods

A total 170 Korean men with impaired spermatogenesis and 272 normal controls were screened. The coding regions including exon-intron boundaries of EGR4 were sequenced by PCR-direct sequencing method.

Results

We identified eight sequence variations in the coding region and 3′-UTR regions of the EGR4 gene. Four were nonsynonymous variants (rs771189047, rs561568849, rs763487015, and rs546250227), three were synonymous variants (rs115948271, rs528939702, and rs7558708), and one variant (rs2229294) was localized in the 3′-UTR. Three nonsynonymous variants [c.65_66InsG (p. Cys23Leufs*37), c.236C > T (p. Pro79Leu), c.1294G > T (p. Val432Leu)] and one synonymous variant [c.1230G > A (p. Thr410)] were not detected in controls. To evaluate the pathogenic effects of nonsynonymous variants, we used seven prediction methods. The c.214C > A (p. Arg72Ser) and c.236C > T (p. Pro79Leu) variants were predicted as “damaging” by SIFT and SNAP². The c.65_66insG (p. Cys23Leufs*37) variants were predicted as “disease causing” by Mutation Taster, SNPs &GO and SNAP². The c.867C > G (p. Leu289) variants were predicted as “disease causing” only by Mutation Taster.

Conclusion

To date, this study is the first to screen the EGR4 gene in relation to male infertility. However, our findings did not clearly explain how nonsynonymous EGR4 variations affect spermatogenesis. Therefore, further studies are required to validate the functional impact of EGR4 variations on spermatogenesis.

Electronic supplementary material

The online version of this article (doi:10.1186/s12881-017-0408-5) contains supplementary material, which is available to authorized users.

Nab2 maintains thymus cellularity with aging and stress

Thymic cellularity is influenced by a variety of biological and environmental factors, such as age and stress; however, little is known about the molecular genetic mechanisms that regulate this process. Immediate early genes of the Early growth response (Egr) family have critical roles in immune function and response to environmental stress. The transcription factors, Egr1, Egr2 and Egr3, play roles in the thymus and in peripheral T-cell activation. Nab2, which binds Egrs 1, 2, and 3 as a co-regulator of transcription, also regulates peripheral T-cell activation. However, a role for Nab2 in the thymus has not been reported. Using Nab2-deficient (KO) mice we found that male Nab2KO mice have reduced thymus size and decreased numbers of thymocytes, compared with age-matched wildtype (WT) mice. Furthermore, the number of thymocytes in Nab2KO males decreases more rapidly with age. This effect is sex-dependent as female Nab2KO mice show neither reduced thymocyte numbers nor accelerated thymocyte loss with age, compared to female WT littermates. Since stress induces expression of Nab2 and the Egrs, we examined whether loss of Nab2 alters stress-induced decrease in thymic cellularity. Restraint stress induced a significant decrease in thymic cellularity in Nab2KO and WT mice, with significant changes in the thymocyte subset populations only in the Nab2KO mice. Stress reduced the percentage of DP cells by half and increased the percentage of CD4SP and CD8SP cells by roughly three-fold in Nab2KO mice. These findings indicate a requirement for Nab2 in maintaining thymocyte number in male mice with age and in response to stress.

Gonadotropin releasing hormone activation of the mTORC2/Rictor complex regulates actin remodeling and ERK activity in LβT2 cells

The mammalian target of rapamycin (mTOR) assembles into two different multi-protein complexes, mTORC1 and mTORC2. The mTORC2 complex is distinct due to the unique expression of the specific core regulatory protein Rictor (rapamycin-insensitive companion of mTOR). mTORC2 has been implicated in regulating actin cytoskeletal reorganization but its role in gonadotrope function is unknown. Using the gonadotrope-derived LβT2 cell line, we find that the GnRH agonist buserelin (GnRHa) phosphorylates both mTOR and Rictor. Interestingly, inhibition of mTORC2 blunts GnRHa-induced cyto-architectural rearrangements. Coincident with blunting of actin reorganization, inhibition of mTORC2 also attenuates GnRHa-mediated activation of both protein kinase C (PKC) and extracellular signal regulated kinase (ERK). Collectively, our data suggests that GnRHa-mediated mTORC2 activation is important in facilitating actin reorganization events critical for initiating PKC activity and subsequent ERK phosphorylation in the gonadotrope-derived LβT2 cell line.

Gene and miRNA expression profiles in PBMCs from patients with severe and mild emphysema and PiZZ alpha1-antitrypsin deficiency

INTRODUCTION

COPD has complex etiologies involving both genetic and environmental determinants. Among genetic determinants, the most recognized is a severe PiZZ (Glu342Lys) inherited alpha1-antitrypsin deficiency (AATD). Nonetheless, AATD patients present a heterogeneous clinical evolution, which has not been completely explained by sociodemographic or clinical factors. Here we performed the gene expression profiling of blood cells collected from mild and severe COPD patients with PiZZ AATD. Our aim was to identify differences in messenger RNA (mRNA) and microRNA (miRNA) expressions that may be associated with disease severity.

MATERIALS AND METHODS

Peripheral blood mononuclear cells from 12 COPD patients with PiZZ AATD (6 with severe disease and 6 with mild disease) were used in this pilot, high-throughput microarray study. We compared the cellular expression levels of RNA and miRNA of the 2 groups, and performed functional and enrichment analyses using the Kyoto Encyclopedia of Genes and Genomes (KEGG) and Gene-ontology (GO) terms. We also integrated the miRNA and the differentially expressed putative target mRNA. For data analyses, we used the R statistical language R Studio (version 3.2.5).

RESULTS

The severe and mild COPD-AATD groups were similar in terms of age, gender, exacerbations, comorbidities, and use of augmentation therapy. In severe COPD-AATD patients, we found 205 differentially expressed genes (DEGs) (114 upregulated and 91 downregulated) and 28 miRNA (20 upregulated and 8 downregulated) compared to patients with mild COPD-AATD disease. Of these, hsa-miR-335-5p was downregulated and 12 target genes were involved in cytokine signaling, MAPK/mk2, JNK signaling cascades, and angiogenesis were much more highly expressed in severe compared with mild patients.

CONCLUSIONS

Despite the small sample size, we identified downregulated miRNA (hsa-miR-335) and the activation of pathways related to inflammation and angiogenesis on comparing patients with severe vs mild COPD-AATD. Nonetheless, our findings warrant further validation in large studies.

Expression of Egr3 in mouse gonads and its localization and function in oocytes

Objective

The early growth response (Egr) family consists of four members (Egr1, Egr2, Egr3, and Egr4) that are zinc finger transcription factors. Among them, Egr3 is involved in transcriptional regulation of target genes during muscle spindle formation and neurite outgrowth. We previously showed that the immunoreactive Egr3 is localized on oocyte spindle and accumulate near the microtubule organizing center during meiosis I in mice. Egr3 was also shown to be localized on spermatocytes. We herein investigated if Egr3 is expressed in mouse gonads and if Egr3 blockade results in any defect in oocyte maturation.

Methods

Expression of Egr3 in mouse gonads was examined by reverse transcription-polymerase chain reaction. Full-length Egr3 and truncated Egr3 (ΔEgr3) complementary RNAs (cRNAs) with Xpress tag at N-terminus and DsRed2 at C-terminus, and small interfering RNA (siRNA) targeting Egr3 were microinjected into mouse oocytes at germinal vesicle stage. Localization of microinjected Egr3 was examined by confocal live imaging and immunofluorescence staining.

Results

Egr3 mRNA was detected in mouse ovaries and testes from 1 to 4 week-old mice. An uncharacterized longer transcript containing 5′untranslated region was also detected in 3 and 4 week-old gonads. Microinjected Xpress-Egr3-DsRed2 or Xpress-ΔEgr3-DsRed2 localized to nuclei and chromosomes during meiotic progression. Microinjection of these cRNAs or Egr3 siRNA in oocytes did not affect meiotic maturation. Immunofluorescence staining of Egr3 in Xpress-ΔEgr3-DsRed2-injected oocytes showed a positive signal only on meiotic spindle, suggesting that this antibody does not detect endogenous or exogenous Egr3 in mouse oocytes.

Conclusion

The results show that Egr3 localizes to chromosomes during meiotic progression and that certain antibodies may not faithfully represent localization of target proteins in oocytes. Egr3 seems to be dispensable during oocyte maturation in mice.

EGR2 is a gonadotropin-induced survival factor that controls the expression of IER3 in ovarian granulosa cells

Pituitary gonadotropins are key hormones that orchestrate the growth and development of ovarian follicles. However, limited information is available on intra-ovarian factors that mediate the actions of gonadotropins. In this study, we identified that the early growth response 2 gene (EGR2) is a gonadotropin-inducible gene in granulosa cells of rats and humans. Analysis of consensus EGR-binding elements (EBEs) showed that the immediate early response 3 gene (IER3) is a novel transcriptional target gene of EGR2 as confirmed by the luciferase assay, electrophoretic mobility-shift assay (EMSA), chromatin immunoprecipitation (ChIP), and western blot analysis. Overexpression of EGR2 promoted survival of KGN human granulosa-derived cells in which IER3 acts as a mediator; knockdown of EGR2 induced death in KGN cells. Additionally, EGR2 was found to regulate the expression of myeloid cell leukemia 1 (MCL-1), which belongs to the BCL-2 family of proteins regulating cell survival. Thus, this study identified a novel signaling axis, comprised of gonadotropins-EGR2-IER3, which is important for the survival of granulosa cells during folliculogenesis.

Mouse Models of Gonadotrope Development

The pituitary gonadotrope is central to reproductive function. Gonadotropes develop in a systematic process dependent on signaling factors secreted from surrounding tissues and those produced within the pituitary gland itself. These signaling pathways are important for stimulating specific transcription factors that ultimately regulate the expression of genes and define gonadotrope identity. Proper gonadotrope development and ultimately gonadotrope function are essential for normal sexual maturation and fertility. Understanding the mechanisms governing differentiation programs of gonadotropes is important to improve treatment and molecular diagnoses for patients with gonadotrope abnormalities. Much of what is known about gonadotrope development has been elucidated from mouse models in which important factors contributing to gonadotrope development and function have been deleted, ectopically expressed, or modified. This chapter will focus on many of these mouse models and their contribution to our current understanding of gonadotrope development.