Cell-specific expression of estrogen-responsive genes in the uteri of cyclic, early pregnant and ovariectomized ewes

The uncommon function and mechanism of the common enzyme glyceraldehyde-3-phosphate dehydrogenase in the metamorphosis of Helicoverpa armigera

Glyceraldehyde-3-phosphate dehydrogenase (GAPDH), a key enzyme in glycolysis, is commonly used as an internal reference gene in humans, mice, and insects. However, the function of GAPDH in insect development, especially in metamorphosis, has not been reported. In the present study, Helicoverpa armigera and Spodoptera frugiperda ovarian cell lines (Sf9 cells) were used as materials to study the function and molecular mechanism of GAPDH in larval metamorphosis. The results showed that HaGAPDH was more closely related to GAPDH of S. frugiperda and Spodoptera litura. The transcript peaks of HaGAPDH in sixth instar larvae were 6L-3 (epidermal and midgut) and 6L-1 (fat body) days, and 20E and methoprene significantly upregulated the transcripts of HaGAPDH of larvae in qRT-PCR. HaGAPDH–GFP–His was specifically localized in mitochondria in Sf9 cells. Knockdown of HaGAPDH by RNA interference (RNAi) in sixth instar larvae resulted in weight loss, increased mortality, and decreases in the pupation rate and emergence rates. HaGAPDH is directly bound to soluble trehalase (HaTreh1) physically and under 20E treatment in yeast two-hybrid, coimmunoprecipitation, and colocalization experiments. In addition, knockdown of HaGAPDH increased the Treh1 activity, which in turn decreased the trehalose content but increased the glucose content in larvae. Therefore, these data demonstrated that GAPDH controlled the glucose content within the normal range to ensure glucose metabolism and metamorphosis by directly binding with HaTreh1.

Identification of Estrus in Sows Based on Salivary Proteomics

The estrus cycle of multiparous Large White sows was divided into three stages to solve the problems of heavy workload and low accuracy of the traditional estrus identification method in pig production. Saliva protein was extracted from the oral saliva of multiparous sows. Label-free quantitative proteomics was used to detect salivary proteome, and MaxQuant software was used for quality control. Results showed that 246 proteins were identified in the three stages, where 40 proteins were significantly different (p < 0.05). The total proteins identified were enriched by STEM software and the protein function was annotated by using the ClueGO plug-in in the Cytoscape software. The results were enriched to eight different trends. The annotated items were related to protein synthesis and processing and estrogen response. Gene ontology and the Kyoto Encyclopedia of Genes and Genomes enrichment analysis of differential proteins involved in the pathways and entries included oocyte meiosis, response to estradiol, and oogenesis. Further interaction analysis showed that an interaction occurred between P00355, F1SHL9, P28491, F1SDR7, F2Z558, F1RYY6, and F2Z5G3 proteins. The findings served as a basis for revealing the changes in salivary protein content in the sow estrus cycle and provided a reference for the development of an estrus identification kit/test strip in the next step.

Placental development during early pregnancy in sheep: nuclear estrogen and progesterone receptor mRNA expression in the utero-placental compartments

Sex steroid hormones are major regulators of uterine and placental growth and functions, as well as many other biological processes. To examine the mRNA expression of nuclear estrogen (ESR1 and 2) and progesterone (PGRAB and B) receptors in different compartments of the uterus and placenta, tissues were collected in experiment 1 on days 16, 20, and 28 after natural mating (NAT) and on day 10 after estrus (nonpregnant controls [NP]); and in experiment 2 on day 22 of NAT, and pregnancies established after transfer of embryos generated through mating of FSH-treated ewes (NAT-ET), in vitro fertilization (IVF), or in vitro activation (parthenotes). In experiment 1, ESR1 expression in endometrial stroma (ES), endometrial glands (EGs), and myometrial blood vessels (MBVs), ESR2 in endometrial blood vessels (EBV), PGRAB in ES, and PGRB in ES, EG, and MBV was greater in pregnant than NP ewes depending on the day of pregnancy. The day of pregnancy affected the expression of ESR1 in MBV, ESR2 in EBV and MBV, and PGRAB in ES. In experiment 2, ESR1, PGRAB, and PGRB in EG, but not in other compartments, was greater in NAT-ET than NAT, and PGRB was greater for NAT-ET than IVF. These data demonstrate that ESR and PGR expression differ in pregnant versus NP ewes in selected compartments and was affected by pregnancy stage or embryo origin in selected utero-placental compartments. Thus, sex steroid hormone mRNA expression is differentially regulated in a spatiotemporal manner in the uterus and placenta and is affected by the application of assisted reproductive technology in sheep.

Expression of progesterone receptor protein in the ovine uterus during the estrous cycle: Effects of nutrition, arginine and FSH

To evaluate expression of progesterone receptor (PGR) AB in follicle stimulating hormone (FSH)-treated or non-treated sheep administered with arginine (Arg) or saline (Sal) fed a control (C), excess (O) or restricted (U) diet, uterine tissues were collected at the early, mid and/or late luteal phases. In exp. 1, ewes from each diet were randomly assigned to one of two treatments, Arg or Sal administration three times daily from day 0 of the first estrous cycle until uterine tissue collection. In exp. 2, ewes were injected twice daily with FSH on days 13-15 of the first estrous cycle. Uterine tissues were immunostained to detect PGR followed by image analysis. PGR were detected in luminal epithelium (LE), endometrial glands (EG), endometrial stroma (ES), myometrium (Myo), and endometrial and myometrial blood vessels. The percentage of PR-positive cells and/or intensity of staining were affected by phase of the estrous cycle, plane of nutrition, and/or FSH but not by Arg. In exp. 1, percentage of PGR-positive cells in LE and EG but not in ES and Myo was greater at the early and mid than late luteal phase, was not affected by plane of nutrition, and was similar in LE and EG. Intensity of staining was affected by phase of the estrous cycle and plane of nutrition in LE, EG and Myo, and was the greatest in LE, less in EG, and least in ES and Myo. In exp. 2, percentage of PGR-positive cells in LE, EG, ES and Myo was affected by phase of the estrous cycle, but not by plane of nutrition; was greater at the early than mid luteal phase; and was greatest in LE and EG, less in luminal (superficial) ES and Myo and least in deep ES. Intensity of staining was affected by phase of the estrous cycle and plane of nutrition in all compartments but ES, and was the greatest in LE and luminal EG, less in deep EG, and least in ES and Myo. Comparison of data for FSH (superovulated) and Sal-treated (non-superovulated) ewes demonstrated that FSH affected PR expression in all evaluated uterine compartments depending on plane of nutrition and phase of the estrous cycle. Thus, PGR are differentially distributed in uterine compartments, and PGR expression is affected by nutritional plane and FSH, but not Arg depending on phase of the estrous cycle. Such changes in dynamics of PGR expression indicate that diet plays a regulatory role and that FSH-treatment may alter uterine functions.

Maternal hypothyroidism decreases progesterone receptor expression in the cortical subplate of foetal rat brain

Steroid hormones exert profound effects on the development of brain areas controlling complex cognitive function in adulthood. One class, progestins, may contribute by acting on the progestin receptor (PR), which is transiently expressed in a critical layer of developing cortex: the subplate. PR expression in the subplate coincides with the establishment of ongoing cortical connectivity and may play an important organisational role. Identification of the factor(s) that regulate the precise timing of PR expression within subplate may help elucidate the function of PR. Thyroid hormone may interact with hormone response elements within the PR gene. The present study examined the effects of maternal hypothyroidism on levels of PR immunoreactivity (PR-IR) within the foetal subplate. Pregnant rats were made hypothyroid by the administration of methimazole and potassium perchlorate in drinking water. Maternal hypothyroidism significantly decreased PR-IR within the foetal subplate. Using the incorporation of 5-bromo-2'-deoxyuridine (BrDU) during subplate cell neurogenesis (embryonic day 13.5) to determine subplate cell survival in hypothyroid animals, we found that decreases in PR-IR cannot be attributed to significant subplate cell loss but are more likely the result of altered PR expression. Gestational thyroxine replacement to hypothyroid dams prevented the decrease in PR-IR within the subplate. These results identify thyroid hormone as a potential factor in the regulation of PR expression in the developing brain. These results are consistent with the idea that endocrine cross-talk between progesterone and thyroid hormone may be one mechanism by which maternal hypothyroidism alters normal cortical development.

Endometrial population of oestrogen receptors alpha and beta and progesterone receptors A and B during the different phases of the follicular wave of llamas (Lama glama)

The aim of this study was to characterize the distribution of oestrogen receptor (ER)α and ERβ as well as both progesterone receptors isoforms progesterone receptor (PR) A and PRB in the luminal and glandular epithelia and stroma of the endometrium during the different phases of the follicular wave in llamas. Six llamas were examined by transrectal ultrasonography, and a transcervical biopsy was obtained when a follicle at the growing, plateau and regressing phase was recorded. Blood samples were collected at the time of biopsy for hormone determinations. An immunohistochemical technique was used to study receptor populations. Total positive area was evaluated in the different cell types by Image Analysis. Mean diameter measurements of the largest follicle were 6.9, 8.5 and 5.1 mm (p < 0.001) and mean plasma oestradiol-17β concentrations were 27.9 ± 3.26; 30.0 ± 2.79 and 24.0 ± 1.78 pmol/l (p = 0.32) during the growing, plateau and regressing phases, respectively. Immunostaining of ERα was higher in the luminal epithelium during the plateau and regressing phases (p < 0.05) than during the growing phase. More positive cells to ERβ were observed in the glandular epithelium of the growing and plateau phases (p < 0.05) than during the regressing phase. A higher percentage of cells positive to PRB was recorded in the luminal and glandular epithelia during the plateau phase (p < 0.05), while the PRA immunostaining was similar among phases. In brief, this study showed an increased population of ERα and PRB in the luminal epithelium, and only of PRB in the glandular epithelium at the time when an ovulatory follicle is present. The physiological importance of these changes in llamas remains to be elucidated.

Endometrial modifications during early pregnancy in bonnet monkeys (Macaca radiata)

The present study was undertaken to investigate endometrial modifications that occur before embryo invasion in bonnet monkeys (Macaca radiata). These changes were analysed in luminal epithelium, glandular epithelium and stroma of endometrial functionalis on Day 6 post ovulation from pregnant and non-pregnant animals (n = 4 each) by transmission electron microscopy. Distinct features (i.e. loss of columnar shape by epithelial cells, changes in mitochondrial size and diffused apicolateral gap junctions) were observed in the luminal and glandular epithelium in pregnant animals. Stromal compaction was also observed in pregnant animals. Further, immunogold localisation studies demonstrated significantly higher expression (P < 0.05) of oestrogen receptor alpha, an oestrogen-regulated gene, in the glandular epithelium and stroma of the endometrium in pregnant animals compared with non-pregnant animals. Expression of two other genes known to be regulated by oestradiol, namely beta-actin and cyclo-oxygenase-1, were also significantly higher (P < 0.05) in the endometria of pregnant animals. These studies demonstrate marked changes in the endometrium before embryo invasion in bonnet monkeys. These studies also indicate altered oestrogenic activity in the uterine milieu before embryo invasion.

The effects of estrogen and testosterone on gene expression in the rat mesenteric arteries

A dramatic difference exists in the timing of development of cardiovascular disease in men vs. women. The primary candidates underlying the cause of this gender difference are the sex steroids, estrogen and testosterone. The vasculature is considered to be a site of action of these steroids. In spite of these concepts there is little data on the direct effects of estrogen and testosterone on gene expression in the vasculature. In this study, ovariectomized Sprague Dawley rats were treated for 4 days with vehicle (sesame oil), estradiol benzoate (0.15 mg/kg/day), or testosterone (1 mg/kg/day). The mesenteric arteries were obtained, total RNA was extracted, and CodeLink Uniset Rat I DNA microarrays were used to identify differential gene expression. Seven genes were identified as differentially expressed from the DNA microarray data and confirmed by real time RT-PCR. The expression of D site albumin promoter binding protein and fatty acid synthase were increased in response to both estrogen and testosterone. 3 alpha-hydroxysteroid dehydrogenase, interleukin 4 receptor, JunB and c-Fos expression were increased by estrogen but not by testosterone. Aryl hydrocarbon nuclear translocator-like gene was reduced by testosterone. These data identify genes not previously known to be responsive to estrogen and testosterone in the vasculature.

Appropriate 'housekeeping' genes for use in expression profiling the effects of environmental estrogens in fish

Background

Attempts to develop a mechanistic understanding of the effects of environmental estrogens on fish are increasingly conducted at the level of gene expression. Appropriate application of real-time PCR in such studies requires the use of a stably expressed 'housekeeping' gene as an internal control to normalize for differences in the amount of starting template between samples.

Results

We sought to identify appropriate genes for use as internal controls in experimental treatments with estrogen by analyzing the expression of eight functionally distinct 'housekeeping' genes (18S ribosomal RNA [18S rRNA], ribosomal protein l8 [rpl8], elongation factor 1 alpha [ef1a], glucose-6-phosphate dehydrogenase [g6pd], beta actin [bactin], glyceraldehyde-3-phosphate dehydrogenase [gapdh], hypoxanthine phosphoribosyltransferase 1 [hprt1], and tata box binding protein [tbp]) following exposure to the environmental estrogen, 17α-ethinylestradiol (EE₂), in the fathead minnow (Pimephales promelas). Exposure to 10 ng/L EE₂ for 21 days down-regulated the expression of ef1a, g6pd, bactin and gapdh in the liver, and bactin and gapdh in the gonad. Some of these effects were gender-specific, with bactin in the liver and gapdh in the gonad down-regulated by EE₂ in males only. Furthermore, when ef1a, g6pd, bactin or gapdh were used for normalization, the hepatic expression of two genes of interest, vitellogenin (vtg) and cytochrome P450 1A (cyp1a) following exposure to EE₂ was overestimated.

Conclusion

Based on the data presented, we recommend 18S rRNA, rpl8, hprt1 and/or tbp, but not ef1a, g6pd, bactin and/or gapdh, as likely appropriate internal controls in real-time PCR studies of estrogens effects in fish. Our studies show that pre-validation of control genes considering the scope and nature of the experiments to be performed, including both gender and tissue type, is critical for accurate assessments of the effects of environmental estrogens on gene expression in fish.

Sex steroid receptor expression in the oviduct and uterus of sheep with estrus synchronized with progestagen or prostaglandin analogues

The objective of this study was to investigate differences in the expression of estrogen receptor-alpha (ERalpha), progesterone receptor (PR) and the proliferative indexes (Ki-67), in the uterus and oviduct of sheep with estrus synchronized either by prostaglandin analogues (Group PA, n=27) or by treatment with progestagens (Group P, n=29) on days 4 and 7 (day 0=estrus), when the embryos were collected. Immunohistochemical methods were used to quantify ERalpha, PR and Ki-67 in six superficial and deep compartments in the uterus and oviduct. The expression of ERalpha was significantly (P<0.01) lower in progestagen treated ewes than in prostaglandin analogues treated group in the luminal epithelium, superficial glands and superficial stroma in the uterus on day 4. The expression of PR was significantly lower in progesterone treated ewes than in the PA Group in the superficial gland (P<0.05) in both days studied. The lowest expression of PR was observed in the luminal caruncular epithelium and superficial glands in both treatments, obtaining the lowest levels on day 4 (P<0.05). There were significant differences between days 4 and 7 in the Ki-67 immunostaining in the luminal epithelium (P<0.01) and superficial glands (P<0.05). A higher cell proliferation was observed in the uterine epithelium (P<0.05) on day 4 in the animals treated with progestagens. Results indicate that sheep with synchronization of estrus with progestagens showed a reduction of ERalpha and PR protein expression in most of oviductal and uterine cells.