An anti-inflammatory role for glucocorticoids in the ovaries?

Upregulation of coagulation factor V by glucocorticoid in the preovulatory follicles of zebrafish

Increased cortisol levels in the preovulatory follicular fluid suggests a role of glucocorticoid in human ovulation. However, the mechanisms through which cortisol regulates the ovulatory process remain poorly understood. In this study, we examined the upregulation of f5 mRNA by glucocorticoid and its receptor (Gr) in the preovulatory follicles of zebrafish. Our findings demonstrate a significant increase in 11β-hydroxysteroid dehydrogenase type 2 (hsd11b2), a cortisol response gene, in preovulatory follicles. Additionally, hydrocortisone exerts a dose- and time-dependent upregulation of f5 mRNA in these follicles. Importantly, this stimulatory effect is Gr-dependent, as it was completely abolished in gr-/- mutants. Furthermore, site-directed mutagenesis identified a glucocorticoid response element (GRE) in the promoter of zebrafish f5. Interestingly, successive incubation of hydrocortisone and the native ovulation-inducing steroid, progestin (17α,20β-dihydroxy-4-pregnen-3-one, DHP), further enhanced f5 expression in preovulatory follicles. Overall, our results indicate that the dramatic increase of f5 expression in preovulatory follicles is partially attributable to the regulation of glucocorticoid and Gr.

The intrafollicular concentrations of biologically active cortisol in women rise abruptly shortly before ovulation and follicular rupture

STUDY QUESTION

What is the temporal activity and the concentration in follicular fluid (FF) of the anti-inflammatory steroid cortisol during the ovulatory process in humans?

SUMMARY ANSWER

Intrafollicular concentrations of cortisol become massively upregulated close to ovulation concomitant with an exceptionally high biological activity securing a timely and efficient termination of inflammatory processes.

WHAT IS KNOWN ALREADY

Ovulation has been described as a local, controlled inflammatory process resulting in the degeneration of the follicle wall which facilitate oocyte extrusion. Ovulation also affects the glucocorticoid metabolism of granulosa cells (GCs) and although de novo synthesis of cortisol only occurs in the adrenal cortex, the mid-cycle surge has been shown to induce a change from high expression of HSD11B2, inactivating cortisol to cortisone, to high expression of HSD11B1 which reversibly catalyses cortisol production from cortisone. Furthermore, high concentrations of progesterone and 17OH-progesterone within follicles may cause dislodging of cortisol from cortisol binding protein (CBP) thereby activating the biological activity of cortisol.

STUDY DESIGN, SIZE, DURATION

This prospective cohort study included 50 women undergoing fertility treatment according to a standard antagonist protocol at a university hospital-affiliated fertility clinic in Denmark.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Women donated FF and GCs from one follicle for research purpose aspirated at one of four time points during the process of final maturation of follicles: T = 0 h, T = 12 h, T = 17 h, T = 32 h. A second sample was collected at oocyte pick up at T = 36 h. The concentration of cortisol and cortisone together with a range of sex steroids was measured by LC-MS/MS in FF collected at the five time points mentioned above. Whole genome microarray data, validated by q-PCR analysis, was used to evaluate gene expression of CYP11B1, CYP21A2, HSD11B1, HSD11B2, and NR3C1 in GCs at the same time points.

MAIN RESULTS AND THE ROLE OF CHANCE

The concentration of cortisol was significantly increased from a few nM at 0 h to around 100-140 nM (P ≤ 0.0001) at 32-36 h, whilst cortisone was almost constant from 0 to 17 h at a concentration of between 90 and 100 nM being significantly reduced to 25-40 nM (P ≤ 0.0001) at 32-36 h. This was paralleled by a 690-fold upregulation of HSD11B1 from 0 to 12 h increasing to a more than 20.000-fold change at 36 h. HSD11B2 was quickly downregulated 15- to 20-fold after ovulation induction. Concentrations of progesterone and 17OH-progesterone increased during the ovulatory process to high levels which in essence displaces cortisol from its binding protein CBP due to similar binding affinities. Furthermore, a significant decrease in 11-deoxycortisol expression was seen, but CYP11B1 expression was below detection limit in GCs.

LIMITATIONS, REASONS FOR CAUTION

The study included women undergoing ovarian stimulation and results may differ from the natural cycle. More observations at each specific time point may have strengthened the conclusions. Furthermore, we have not been able to measure the actual active biological concentration of cortisol.

WIDER IMPLICATIONS OF THE FINDINGS

For the first time, this study collectively evaluated the temporal pattern of cortisol and cortisone concentrations during human ovulation, rendering a physiological framework for understanding potential dysregulations in the inflammatory reaction of ovulation.

STUDY FUNDING/COMPETING INTEREST(S)

This research was supported by the University Hospital of Copenhagen, Rigshospitalet, and Novo Nordisk Foundation grant number NNF21OC00700556. Interreg V ÔKS through ReproUnion (www.reprounion.eu); Region Zealand Research Foundation. The funders had no role in study design, collection of data, analyses, writing of the article, or the decision to submit it for publication. The authors have no conflicts of interest to declare.

TRIAL REGISTRATION NUMBER

N/A.

Progesterone modulates HSD11B1-mediated cortisol production in luteinized bovine granulosa cells

Progesterone (P4) and cortisol production increase in luteinized granulosa cells (LGCs) during the periovulatory period, but their interaction is not well established. Therefore, we investigated their interaction in cultured bovine LGCs. Granulosa cells were collected from follicles of 2-5 mm in diameter and cultured in DMEM/F-12 supplemented with 10% fetal calf serum for up to 14 days. P4 production and the expression of steroidogenic acute regulatory protein (STAR), cholesterol side-chain cleavage enzyme (CYP11A1), and 3β-hydroxysteroid dehydrogenase type 1 (HSD3B1) rapidly increased until day 10 and remained high thereafter. No de novo production of cortisol from P4 was detected during the culture period. The expression of 11β-hydroxysteroid dehydrogenase type 1 (HSD11B1), which converts cortisone to cortisol, increased dramatically on day two, decreased until day 8, and remained relatively constant. To investigate how P4 and cortisol influence each other's production, LGCs were treated with trilostane (a P4 synthesis inhibitor), nomegestrol acetate (NA, a synthetic progestogen), P4, and/or cortisol for 24 h on days 6 and 12 of culture. Trilostane suppressed P4 and STAR expression while elevating HSD11B1 and HSD3B1 expression and cortisol production. Concomitant treatment with NA or P4 dose-dependently decreased cortisol production and HSD11B1 and HSD3B1 expression but elevated STAR expression in both days 6 and 12. Conversely, cortisol treatment increased HSD11B1 and HSD3B1 expression and decreased STAR expression without influencing P4 production. These results indicate that progestogens suppress cortisol production by modulating HSD11B1 expression and that progestogens and cortisol differentially regulate STAR, HSD3B1, and HSD11B1 expression in bovine LGCs.

Selenium suppressed the LPS-induced inflammation of bovine endometrial epithelial cells through NF-κB and MAPK pathways under high cortisol background

The bovine uterus is susceptible to infection, and the elevated cortisol level due to stress are common in cows after delivery. The essential trace element selenium plays a pivotal role in the antioxidant and anti-inflammatory defence system of body. This study investigated whether selenium supplementation protected endometrial cells from inflammation in the presence of high-level cortisol. The primary bovine endometrial epithelial cells were subjected to Escherichia coli lipopolysaccharide to establish cellular inflammation model. The gene expression of inflammatory mediators and proinflammatory cytokines was measured by quantitative PCR. The key proteins of NF-κB and MAPK signalling pathways were detected by Western blot and immunofluorescence. The result showed that pre-treatment of Na2 SeO3 (1, 2 and 4 μΜ) decreased the mRNA expression of proinflammatory genes, inhibited the activation of NF-κB and suppressed the phosphorylation of extracellular signal-regulated kinase, P38MAPK and c-Jun N-terminal kinase. This inhibition of inflammation was more apparent in the presence of high-level cortisol (30 ng/mL). These results indicated that selenium has an anti-inflammatory effect, which is mediated via NF-κB and MAPK signalling pathways and is augmented by cortisol in bovine endometrial epithelial cells.

Elevated glucocorticoids during the ovarian follicular phase predict conception in wild female chacma baboons

Mating related behavior during ovarian cycling can be energetically demanding and constitute a significant stressor, requiring physiological responses to mediate investment in reproduction. To better understand the proximate mechanisms underlying these responses, we examine hormonal and behavioral variation across the ovarian cycle during conceptive and nonconceptive cycles in wild female chacma baboons (Papio ursinus). We quantified immunoreactive fecal estradiol, progesterone, and cortisol metabolites for 21 adult females, and calculated activity budgets and rates of received aggression from over 5000 15-min behavioral samples. We found conception to be associated with higher concentrations of both estradiol and cortisol during the follicular phase, but no difference in progesterone between conceptive and nonconceptive cycles for either the follicular or luteal phase. While females spent less time feeding during the follicular compared to the luteal phase, we found no difference in time spent feeding, moving, or copulating between conceptive and nonconceptive cycles of the same phase. Rates of received aggression also were similar across the ovarian cycle, with no difference between conceptive and nonconceptive cycles. Finally, we found positive associations between cortisol and estradiol, indicating that glucocorticoids (GCs) do not suppress hypothalamic-pituitary-gonadal (HPG) activity and reproductive function in this context. Overall, our results suggest that elevated GCs may play an adaptive role in mobilizing energy during sexually receptive periods of ovarian cycling.

Cortisol/glucocorticoid receptor: a critical mediator of the ovulatory process and luteinization in human periovulatory follicles

STUDY QUESTION

Do cortisol/glucocorticoid receptors play an active role in the human ovary during ovulation and early luteinization?

SUMMARY ANSWER

The ovulatory hCG stimulation-induced glucocorticoid receptor signaling plays a crucial role in regulating steroidogenesis and ovulatory cascade in human periovulatory follicles.

WHAT IS KNOWN ALREADY

Previous studies reported an increase in cortisol levels in the human follicular fluid after the LH surge or ovulatory hCG administration. However, little is known about the role of cortisol/glucocorticoid receptors in the ovulatory process and luteinization in humans.

STUDY DESIGN, SIZE, DURATION

This study was an experimental prospective clinical and laboratory-based study. An in vivo experimental study was accomplished utilizing the dominant ovarian follicles from 38 premenopausal women undergoing laparoscopic sterilization. An in vitro experimental study was completed using the primary human granulosa/lutein cells (hGLC) from 26 premenopausal women undergoing IVF.

PARTICIPANTS/MATERIALS, SETTING, METHODS

This study was conducted in a private fertility clinic and academic medical centers. Dominant ovarian follicles were collected before the LH surge and at defined times after hCG administration from women undergoing laparoscopic sterilization. Primary hGLC were collected from women undergoing IVF. hGLC were treated without or with hCG in the absence or presence of RU486 (20 µM; dual antagonist for progesterone receptor and glucocorticoid receptor) or CORT125281 (50 µM; selective glucocorticoid receptor antagonist) for 12 or 36 h. The expression of genes involved in glucocorticoid receptor signaling, steroidogenesis, and ovulatory cascade was studied with RT-quantitative PCR and western blotting. The production of cortisol, corticosterone, and progesterone was assessed by hormone assay kits.

MAIN RESULTS AND THE ROLE OF CHANCE

hCG administration upregulated the expression of hydroxysteroid 11-beta dehydrogenase 1 (HSD11B1), nuclear receptor subfamily 3 group C member 1 (NR3C1), FKBP prolyl isomerase 5 (FKBP5), and FKBP prolyl isomerase 4 (FKBP4) in human ovulatory follicles and in hGLC (P < 0.05). RU486 and CORT125281 reduced hCG-induced increases in progesterone and cortisol production in hGLC. The expression of genes involved in glucocorticoid receptor signaling, steroidogenesis, and the key ovulatory process was reduced by RU486 and/or CORT125281 in hGLC.

LARGE SCALE DATA

N/A.

LIMITATIONS, REASONS FOR CAUTION

The role of cortisol/glucocorticoid receptors demonstrated using the hGLC model may not fully reflect their physiological roles in vivo.

WIDER IMPLICATIONS OF THE FINDINGS

Successful ovulation and luteinization are essential for female fertility. Women with dysregulated cortisol levels often suffer from anovulatory infertility. Deciphering the functional role of glucocorticoid receptor signaling in human periovulatory follicles enhances our knowledge of basic ovarian physiology and may provide therapeutic insights into treating infertility in women.

STUDY FUNDING/COMPETING INTEREST(S)

This study was supported by P01HD71875 (to M.J., T.E.C., and M.B.) and R01HD096077 (to M.J.) from the Foundation for the National Institutes of Health and the BTPSRF of the University of Kentucky Markey Cancer Center (P30CA177558). The authors report no competing interests.

TRIAL REGISTRATION NUMBER

N/A.

miRNA-mRNA analysis of sheep adrenal glands reveals the network regulating reproduction

Background

The adrenal gland participates in the process of sheep reproduction. MicroRNAs (miRNAs), endogenous small noncoding RNAs, regulate gene expression at the posttranscriptional level. However, the miRNA-mRNA network profile of adrenal glands relating to reproduction in sheep is still not well-studied. As sheep with FecB^BB genotype show higher lambing number compare with the sheep with FecB⁺⁺ genotype. This research aims to compare gene expression by small RNA-seq in adrenal tissues at follicular (F) and luteal (L) phases in FecB^BB (MM) and FecB⁺⁺ (ww) sheep. After analysis of gene expression, significant differentially expressed microRNAs (DEMs) and corresponding target genes were identified.

Results

A total of 180 miRNAs were found in this study, of which 19 DEMs were expressed in the four comparison groups (MM_F_A vs. MM_L_A, MM_F_A vs. ww_F_A, MM_L_A vs. ww_L_A, ww_F_A vs. ww_L_A). Subsequently, 354 target genes of 19 DEMs were predicted by integrated analysis. Cluster analysis was performed by K_means_cluster, and the expression patterns of these DEMs were separated into four subclusters. Functional analysis of target genes was performed by Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG). The results indicated that the target genes were involved mainly in the Notch signaling pathway, signal transduction, cell communication, innate immune response and amino acid metabolism. Specifically, the Notch signaling pathway, biosynthetic process and metabolic process of pyrimidine nucleotide and amino acid metabolism appear to play key regulatory roles in the sheep fertility trait. Furthermore, miRNA-mRNA interaction networks were constructed by differentially expressed genes combined with our previous study of transcriptome data. The results showed that several key genes, including TDRD3, ANAPC7, CCNL2, BRD2 and MUT, were related to the transformation from the follicular phase to the luteal phase. PLAC8L1, NFAT5, DDX24 and MBD1 were related to the high fecundity of small tail Han sheep.

Conclusions

In this study, the miRNA transcriptome profile was identified, and miRNA-mRNA interaction networks were constructed in adrenal gland tissue of small tail Han sheep, the interaction between miR-370-3p and its targets were considered to play a major role in the reproduction regulation process. The results enriched the number of known miRNAs in adrenal glands and provided novel ideas and further information to demonstrate posttranscriptional regulation mechanisms at follicular and luteal phases in different genotypes of small tail Han sheep.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12863-022-01060-y.

Involvement of BMP-15 in glucocorticoid actions on ovarian steroidogenesis by rat granulosa cells

To elucidate the impact of glucocorticoids on ovarian steroidogenesis and its molecular mechanism by focusing on bone morphogenetic proteins (BMPs), we examined the effect of dexamethasone (Dex) on estradiol and progesterone synthesis by using primary culture of rat granulosa cells. It was revealed that Dex treatment dose-dependently decreased estradiol production but increased progesterone production induced by follicle-stimulating hormone (FSH) by granulosa cells. In accordance with the effects of Dex on estradiol synthesis, Dex suppressed P450arom mRNA expression and cAMP synthesis induced by FSH. Dex treatment in turn enhanced basal as well as FSH-induced levels of mRNAs encoding the enzymes for progesterone synthesis including P450scc and 3βHSD but not StAR and 20αHSD. Of note, Dex treatment significantly upregulated transcription of the BMP target gene Id-1 and Smad1/5/9 phosphorylation in the presence of BMP-15 among the key ovarian BMP ligands. It was also found that Dex treatment increased the expression level of BMP type-I receptor ALK-6 among the type-I and -II receptors for BMP-15. Inhibitory Smad6/7 expression was not affected by Dex treatment. On the other hand, BMP-15 treatment upregulated glucocorticoid receptor (GR) expression in granulosa cells. Collectively, it was revealed that glucocorticoids elicit differential effects on ovarian steroidogenesis, in which GR and BMP-15 actions are mutually enhanced in granulosa cells.

Nuclear receptors: Key regulators of somatic cell functions in the ovulatory process

The development of the ovarian follicle to its culmination by ovulation is an essential element of fertility. The final stages of ovarian follicular growth are characterized by granulosa cell proliferation and differentiation, and steroid synthesis under the influence of follicle-stimulating hormone (FSH). The result is a population of granulosa cells poised to respond to the ovulatory surge of luteinizing hormone (LH). Members of the nuclear receptor superfamily of transcription factors play indispensable roles in the regulation of these events. The key regulators of the final stages of follicular growth that precede ovulation from this family include the estrogen receptor beta (ESR2) and the androgen receptor (AR), with additional roles for others, including steroidogenic factor-1 (SF-1) and liver receptor homolog-1 (LRH-1). Following the LH surge, the mural and cumulus granulosa cells undergo rapid changes that result in expansion of the cumulus layer, and a shift in ovarian steroid hormone biosynthesis from estradiol to progesterone production. The nuclear receptor best associated with these events is LRH-1. Inadequate cumulus expansion is also observed in the absence of AR and ESR2, but not the progesterone receptor (PGR). The terminal stages of ovulation are regulated by PGR, which increases the abundance of the proteases that are directly responsible for rupture. It further regulates the prostaglandins and cytokines associated with the inflammatory-like characteristics of ovulation. LRH-1 regulates PGR, and is also a key regulator of steroidogenesis, cellular proliferation, and cellular migration, and cytoskeletal remodeling. In summary, nuclear receptors are among the panoply of transcriptional regulators with roles in ovulation, and several are necessary for normal ovarian function.

Human granulosa cells function as innate immune cells executing an inflammatory reaction during ovulation: a microarray analysis

Ovulation has been compared to a local inflammatory reaction. We performed an in silico study on a unique, PCR validated, transcriptome microarray study to evaluate if known inflammatory mechanisms operate during ovulation. The granulosa cells were obtained in paired samples at two different time points during ovulation (just before and 36 hours after ovulation induction) from nine women receiving fertility treatment. A total of 259 genes related to inflammation became significantly upregulated during ovulation (2-80 fold, p<0.05), while specific leukocyte markers were absent. The genes and pathway analysis indicated NF-KB-, MAPK- and JAK/STAT signalling (p<1.0E-10) as the major pathways involved in danger recognition and cytokine signalling to initiate inflammation. Upregulated genes further encoded enzymes in eicosanoid production, chemo-attractants, coagulation factors, cell proliferation factors involved in tissue repair, and anti-inflammatory factors to resolve the inflammation again. We conclude that granulosa cells, without involvement from the innate immune system, can orchestrate ovulation as a complete sterile inflammatory reaction.

Ovulation: Parallels With Inflammatory Processes

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

Maternal mRNA input of growth and stress-response-related genes in cichlids in relation to egg size and trophic specialization

BACKGROUND

Egg size represents an important form of maternal effect determined by a complex interplay of long-term adaptation and short-term plasticity balancing egg size with brood size. Haplochromine cichlids are maternal mouthbrooders showing differential parental investment in different species, manifested in great variation in egg size, brood size and duration of maternal care. Little is known about maternally determined molecular characters of eggs in fishes and their relation to egg size and trophic specialization. Here we investigate maternal mRNA inputs of selected growth- and stress-related genes in eggs of mouthbrooding cichlid fishes adapted to different trophic niches from Lake Tanganyika, Lake Malawi, Lake Victoria and compare them to their riverine allies.

RESULTS

We first identified two reference genes, atf7ip and mid1ip1, to be suitable for cross-species quantification of mRNA abundance via qRT-PCR in the cichlid eggs. Using these reference genes, we found substantial variation in maternal mRNA input for a set of candidate genes related to growth and stress response across species and lakes. We observed negative correlation of mRNA abundance between two of growth hormone receptor paralogs (ghr1 and ghr2) across all haplochromine cichlid species which also differentiate the species in the two younger lakes, Malawi and Lake Victoria, from those in Lake Tanganyika and ancestral riverine species. Furthermore, we found correlations between egg size and maternal mRNA abundance of two growth-related genes igf2 and ghr2 across the haplochromine cichlids as well as distinct clustering of the species based on their trophic specialization using maternal mRNA abundance of five genes (ghr1, ghr2, igf2, gr and sgk1).

CONCLUSIONS

These findings indicate that variations in egg size in closely related cichlid species can be linked to differences in maternal RNA deposition of key growth-related genes. In addition, the cichlid species with contrasting trophic specialization deposit different levels of maternal mRNAs in their eggs for particular growth-related genes; however, it is unclear whether such differences contribute to differential morphogenesis at later stages of development. Our results provide first insights into this aspect of gene activation, as a basis for future studies targeting their role during ecomorphological specialization and adaptive radiation.

The effects of dexamethasone administered during pregnancy on the postpartum spiny mouse ovary

Excessive exposure to glucocorticoids can alter ovarian function by modulating oogenesis, folliculogenesis and steroidogenesis. The aim of the present study was to examine the effects of dexamethasone (DEX) administered during pregnancy on folliculogenesis and corpus luteum development in the postpartum spiny mouse ovary. DEX (125 μg kg^-1 body weight per day) was applied to pregnant spiny mouse from day 20 of gestation to parturition. The obtained ovaries were fixed and used for immunohistochemistry and TEM analysis. The expression of proteins related to apoptosis (caspase-3, Bax, Bcl-2) and autophagy (Beclin1, Lamp1) as well as PCNA and GR receptors were evaluated by western-blot. In comparison with DEX-treated group a higher percentage of TUNEL positive granulosa and luteal cells was observed in the control group. These data were consistent with changes in caspase-3 and Bax expression, which increased in the control and decreased after DEX exposure. In turn, the proliferation index and PCNA expression were higher in the DEX-treated group. Moreover, the higher level of Beclin1, Lamp1, anti-apoptotic Bcl-2 protein and GR was observed in the DEX-treated females than in the control group. Beclin1 and Lamp1 were strongly expressed in luteal cells which exhibited an autophagic ultrastructure. Surprisingly, DEX augmented the number of ovarian follicles and corpora lutea, which resulted in a significant increase in ovarian weight. These findings suggest that DEX exerts anti-apoptotic action on granulosa layer and stimulates follicular maturation. Moreover, DEX induces autophagy in luteal cells promoting cell survival rather than cell death, which can prolong the corpus luteum life span.

Improvement of pregnancy rate by intrauterine administration of dexamethasone and recombinant human leukemia inhibitory factor at the time of embryo transfer in cattle

Bovine embryos (day 5) were cultured to day 10 with or without 100 ng/mL PGF2α in medium supplemented with control; 100 nM Dex; 1,000 U/mL recombinant human leukemia inhibitory factor (rhLIF); or Dex+rhLIF. Although the rates to development to the blastocyst were not significantly different among groups, the hatching rate after additional culture with Dex +/or rhLIF was significantly higher in all supplemented groups than the control (p < 0.05). In the presence of PGF2α, the hatching rate was significantly restored in all supplemented groups relative to the group treated with only PGF2α and the control (p < 0.05). Embryo transfer (ET) was performed with blastocysts (day 7). PGF2α levels of control recipient cows were significantly higher in the circulatory blood samples collected 60 min after ET than in samples collected 60 min before ET (p < 0.005), and were decreased in cows injected with loading medium supplemented with Dex+rhLIF (p < 0.005). Pregnancy rate was significantly higher in the ET group that received supplemented embryo-loading medium than in the non-supplemented control (p < 0.05). The intrauterine administration of Dex and rhLIF at ET prevented increased PGF2α in circulatory blood and resulted in enhanced pregnancy rate.

Detection and activity of 11 beta hydroxylase (CYP11B1) in the bovine ovary

Glucocorticoids (GCs) such as cortisol and corticosterone are important steroid hormones with different functions in intermediate metabolism, development, cell differentiation, immune response and reproduction. In response to physiological and immunological stress, adrenocorticotropic hormone (ACTH) acts on the adrenal gland by stimulating the synthesis and secretion of GCs. However, there is increasing evidence that GCs may also be synthesized by extra-adrenal tissues. Here, we examined the gene and protein expression of the enzyme 11β-hydroxylase P450c11 (CYP11B1), involved in the conversion of 11-deoxycortisol to cortisol, in the different components of the bovine ovary and determined the functionality of CYP11B1in vitro.CYP11B1mRNA was expressed in granulosa and theca cells in small, medium and large antral ovarian follicles, and CYP11B1 protein was expressed in medium and large antral follicles. After stimulation by ACTH, we observed an increased secretion of cortisol by the wall of large antral follicles. We also observed a concentration-dependent decrease in the concentration of cortisol in response to metyrapone, an inhibitor of CYP11B1. This decrease was significant at 10−5 µM metyrapone. In conclusion, this study demonstrated for the first time the presence of CYP11B1 in the bovine ovary. This confirms that there could be a local synthesis of GCs in the bovine ovary and therefore a potential endocrine responder to stress through these hormones.

Glucocorticoid metabolism in equine follicles and oocytes

The objective of this study was to determine whether (1) systemic and intrafollicular cortisol concentrations in horses are directly related and (2) supraphysiological levels of glucocorticoids affect in vitro maturation (IVM) rates of oocytes. Specifically, we studied the (1) changes in the intrafollicular cortisol and progesterone in context with granulosa cell gene expression during maturation of equine follicles (from 5-9 mm, 10-14 mm, 15-19 mm, 20-24 mm, and ≥25 mm in diameter) and (2) effects of cortisol supplementation on IVM rates and gene expression of equine cumulus-oocyte complexes (COCs). For these purposes, follicular fluid, granulosa cells, and COCs were collected from 12 mares (mean age 8.6 ± 0.5 yr) by transvaginal aspiration. Cortisol and progesterone concentrations in follicular fluid from follicles ≥25 mm were greater (P < 0.05) than in all other follicle classes and were positively correlated (r = 0.8; P < 0.001). Plasma concentrations of cortisol and progesterone did not differ before and after follicle aspiration (P > 0.05). In granulosa cells, gene expression of NR3C1, HSD11B1, HSD11B2, and CYP21A2 did not differ (P > 0.05) among different follicle classes. Maturation rates were similar (P > 0.05) among groups, regardless of the cortisol concentration in the IVM medium. In cumulus cells, messenger RNA expression of genes involved in glucocorticoid mechanism and apoptosis was either increased (NR3C1 and BCL2) or decreased (HSD11B2) by treatment (P < 0.01). In oocytes, gene expression of maturation markers (BMP15 and GDF9) was affected (P < 0.001) by cortisol treatment. This study demonstrates the involvement of glucocorticoids in follicle and oocyte maturation and cortisol modulation by HSD11B2 in equine COCs. Our data provide further information for understanding the normal ovarian endocrine physiology which might in turn also help improve equine assisted reproduction techniques.

Autoantibodies to Heat-Shock Protein, HSPA5, and Epitope Spreading: High-Dose Dexamethasone Therapy Rescues Ovarian Function in Experimental Autoimmune Ovarian Insufficiency Mouse Model

PROBLEM

Role of autoantibodies to heat-shock protein 70 isoform, HSPA5, both alone or in combination with other antigenic peptides in epitope spreading and effect of high-dose dexamethasone to overcome this.

METHOD OF STUDY

Experimental autoimmune premature ovarian insufficiency mouse model generated by immunization with immunodominant epitopes of HSPA5 alone or in combination with other antigenic peptides. Two doses of dexamethasone treatment are given to the latter group. Immunosorbent assay and Western blot analysis were undertaken to detect cross-reactivity. Hormonal estimations, histological evaluation, and fertility studies were performed to assess treatment efficacy.

RESULTS

One of the immunodominant epitopes of HSPA5 led to epitope spreading. Of the two doses, 100 mg was more effective in rescuing fertility.

CONCLUSIONS

We postulate that the shared immunodominant peptide could be included in a peptide array to detect both HSAP5 and HSP90β autoantibodies for early diagnosis or prognosis of aPOI and customized glucocorticoid therapy for such subjects.

Role of Glucocorticoids in Cystic Ovarian Disease: Expression of Glucocorticoid Receptor in the Bovine Ovary

The aim of this study was to characterize the expression of glucocorticoid receptor (GR) in the components of normal bovine ovary and in animals with cystic ovarian disease (COD). Changes in the protein and mRNA expression levels were determined in control cows and cows with COD by immunohistochemistry and real-time PCR. GR protein expression in granulosa cells was higher in cysts from animals with spontaneous COD and adrenocorticotropic hormone-induced COD than in tertiary follicles from control animals. In theca interna cells, GR expression was higher in cysts from animals with spontaneous COD than in tertiary follicles from control animals. The increase in GR expression observed in cystic follicles suggests a mechanism of action for cortisol and its receptor through the activation/inactivation of specific transcription factors. These factors could be related to the pathogenesis of COD in cattle.

The value of eutherian-marsupial comparisons for understanding the function of glucocorticoids in female mammal reproduction

This article is part of a Special Issue "SBN 2014". Chronic stress is known to inhibit female reproductive function. Consequently, it is often assumed that glucocorticoid (GC) concentrations should be negatively correlated with reproductive success because of the role they play in stress physiology. In contrast, a growing body of evidence indicates that GCs play an active role in promoting reproductive function. It is precisely because GCs are so integral to the entire process that disruptions to adrenal activity have negative consequences for reproduction. The goal of this paper is to draw attention to the increasing evidence showing that increases in adrenal activity are important for healthy female reproduction. Furthermore, we outline several hypotheses about the functional role(s) that GCs may play in mediating reproduction and argue that comparative studies between eutherian and marsupial mammals, which exhibit some pronounced differences in reproductive physiology, may be particularly useful for testing different hypotheses about the functional role of GCs in reproduction. Much of our current thinking about GCs and reproduction comes from research involving stress-induced levels of GCs and has led to broad assumptions about the effects of GCs on reproduction. Unfortunately, this has left a gaping hole in our knowledge about basal GC levels and how they may influence reproductive function, thereby preventing a broader understanding of adrenal physiology and obscuring potential solutions for reproductive dysfunction.

Glucocorticoid metabolism in the bovine cumulus-oocyte complex matured in vitro

Glucocorticoid action in target organs is regulated by relative activities of 11β-HSD type 1 (HSD11B1) that mainly converts cortisone to active cortisol and type 2 (HSD11B2) that inactivates cortisol to cortisone. HSD11Bs have been shown to be expressed in the ovary of various species. However, little is known about the expression and activity of HSD11Bs in the bovine cumulus-oocyte complex (COC). In the present study, we investigated the expression and activities of HSD11Bs in in vitro-matured (IVM) bovine COCs. Bovine COCs were matured in M199 supplemented with or without FSH and FCS. The expression of HSD11B1 and HSD11B2 was measured by using quantitative RT-PCR in denuded oocytes (DO) and cumulus cells (CC). Reductive and oxidative activities of HSD11Bs were determined by radiometric conversion assay using labeled cortisol, cortisone or dexamethasone in intact COCs, DO or CC in the presence or absence of 11-keto-progesterone (11kP), a selective inhibitor of HSD11B2. The presence of HSD11Bs in the oocyte was examined by immunofluorescence microscopy. Oocytes exclusively expressed HSD11B2 and its expression and activity were largely unchanged during IVM. CC, on the other hand, exclusively expressed HSD11B1 and its expression and activity were upregulated as IVM progressed. As a result, the net glucocorticoid metabolism shifted from inactivation to activation towards the end of IVM. These results indicate that the bovine COC is capable of modulating local glucocorticoid concentration and, by doing so, may create an environment that is favorable to ovulating oocyte for maturation, fertilization and subsequent development.

Glucocorticoid Regulation of Reproduction

It is well accepted that stress, measured by increased glucocorticoid secretion, leads to profound reproductive dysfunction. In times of stress, glucocorticoids activate many parts of the fight or flight response, mobilizing energy and enhancing survival, while inhibiting metabolic processes that are not necessary for survival in the moment. This includes reproduction, an energetically costly procedure that is very finely regulated. In the short term, this is meant to be beneficial, so that the organism does not waste precious energy needed for survival. However, long-term inhibition can lead to persistent reproductive dysfunction, even if no longer stressed. This response is mediated by the increased levels of circulating glucocorticoids, which orchestrate complex inhibition of the entire reproductive axis. Stress and glucocorticoids exhibits both central and peripheral inhibition of the reproductive hormonal axis. While this has long been recognized as an issue, understanding the complex signaling mechanism behind this inhibition remains somewhat of a mystery. What makes this especially difficult is attempting to differentiate the many parts of both of these hormonal axes, and new neuropeptide discoveries in the last decade in the reproductive field have added even more complexity to an already complicated system. Glucocorticoids (GCs) and other hormones within the hypothalamic-pituitary-adrenal (HPA) axis (as well as contributors in the sympathetic system) can modulate the hypothalamic-pituitary-gonadal (HPG) axis at all levels-GCs can inhibit release of GnRH from the hypothalamus, inhibit gonadotropin synthesis and release in the pituitary, and inhibit testosterone synthesis and release from the gonads, while also influencing gametogenesis and sexual behavior. This chapter is not an exhaustive review of all the known literature, however is aimed at giving a brief look at both the central and peripheral effects of glucocorticoids on the reproductive function.

Cyclic changes in cortisol across the estrous cycle in parous and nulliparous Asian elephants

In the context of reproduction, glucocorticoids (GCs) are generally considered to have negative effects. However, in well-studied model species, GCs fluctuate predictability across the estrous cycles, and short-term increases promote healthy ovarian function. Reproductive challenges have plagued captive elephant populations, which are not currently self-sustaining. Efforts to understand reproductive dysfunction in elephants have focused on the suppressive effects of cortisol, but the potential permissive or stimulatory effects of cortisol are unknown. In this study, we provide a detailed examination of cortisol patterns across the estrous cycle in Asian elephants (Elephas maximus). Time series analysis was used to analyze cortisol and progesterone data for a total of 73 cycles from eight females. We also compared cortisol profiles between females that successfully conceived and females that failed to conceive despite repeated mating attempts. Our results revealed that cortisol fluctuates predictably across the estrous cycle, with a peak during the second half of the follicular phase followed by low levels throughout the luteal phase. Furthermore, this pattern was significantly altered in nulliparous females; cortisol concentrations did not decline during the luteal phase to the same extent as in parous females. This study highlights the complexity of cortisol signaling and suggests future directions for understanding the role of cortisol in reproductive dysfunction.

Ovarian localization of 11β-hydroxysteroid dehydrogenase (11βHSD): effects of ACTH stimulation and its relationship with bovine cystic ovarian disease

Cystic ovarian disease (COD) is an important cause of infertility in cattle, and ACTH has been involved in regulatory mechanisms related to ovarian function associated with ovulation, steroidogenesis, and luteal function. Here, we examined the localization of 11β-hydroxysteroid dehydrogenase type 1 (11βHSD1) and 11βHSD2 proteins in the ovary of healthy cows and animals with spontaneous and ACTH-induced COD and the in vitro response of the follicular wall exposed to ACTH. After stimulation by ACTH, we documented changes in 11βHSD expression and cortisol secretion by the follicular wall of large antral and follicular cysts. Follicular cysts showed a higher constitutive expression of both enzymes, whereas ACTH induced an increase in 11βHSD1 in tertiary follicles and follicular cysts and a decrease in 11βHSD2 in follicular cysts. Moderate expression of 11βHSD1 was observed by immunohistochemistry in granulosa of control animals, with an increase (P < 0.05) from primary to secondary, tertiary, and atretic follicles. The level of immunostaining in theca interna was lower than that in granulosa. The expression of 11βHSD2 was lower in the granulosa of primary follicles than in that of secondary, tertiary, and atretic follicles and was lower in the theca interna than in the granulosa. In ACTH-induced and spontaneously occurring follicular cysts, differences from controls were observed only in the expression of 11βHSD1 in the granulosa, being higher (P < 0.05) than in tertiary follicles. These findings indicate that follicular cysts may be exposed to high local concentrations of active glucocorticoids and indicate a local role for cortisol in COD pathogenesis and in regulatory mechanisms of ovarian function.

Effects of cortisol on pregnancy rate and corpus luteum function in heifers: an in vivo study

To determine whether glucocorticoids affect the function of the bovine corpus luteum (CL) during the estrous cycle and early pregnancy, we examined the effects of exogenous cortisol or reduced endogenous cortisol on the secretion of progesterone (P4) and on pregnancy rate. In preliminary experiments, doses of cortisol and metyrapone (an inhibitor of cortisol synthesis) were established (n=33). Cortisol in effective doses of 10 mg blocked tumor necrosis factor-induced prostaglandin F(2α) secretion as measured by its metabolite (PGFM) concentrations in the blood. Metyrapone in effective doses of 500 mg increased the P4 concentration. Thus, both reagents were then intravaginally applied in the chosen doses daily from Day 15 to 18 after estrus (Day 0) in noninseminated heifers (n=18) or after artificial insemination (n=36). Pregnancy was confirmed by transrectal ultrasonography between Days 28-30 after insemination. Plasma concentrations of P4 were lower in cortisol-treated heifers than in control heifers on Days 17 and 18 of the estrous cycle (P<0.05). However, the interestrus intervals were not different between control and cortisol-treated animals (P>0.05). Moreover, metyrapone increased P4 and prolonged the CL lifespan in comparison to control animals (P<0.05). Interestingly, in inseminated heifers, cortisol increased the pregnancy rate (75%) compared with control animals (58%), whereas metyrapone reduced the pregnancy rate to 16.7% (P<0.05). The overall results suggest that cortisol, depending on the physiological status of heifers (pregnant vs. nonpregnant), modulates CL function by influencing P4 secretion. Cortisol may have a positive influence on CL function during early pregnancy, leading to support of embryo implantation and resulting in higher rates of pregnancy in heifers.

Glucocorticoid regulation of SLIT/ROBO tumour suppressor genes in the ovarian surface epithelium and ovarian cancer cells

The three SLIT ligands and their four ROBO receptors have fundamental roles in mammalian development by promoting apoptosis and repulsing aberrant cell migration. SLITs and ROBOs have emerged as candidate tumour suppressor genes whose expression is inhibited in a variety of epithelial tumours. We demonstrated that their expression could be negatively regulated by cortisol in normal ovarian luteal cells. We hypothesised that after ovulation the locally produced cortisol would inhibit SLIT/ROBO expression in the ovarian surface epithelium (OSE) to facilitate its repair and that this regulatory pathway was still present, and could be manipulated, in ovarian epithelial cancer cells. Here we examined the expression and regulation of the SLIT/ROBO pathway in OSE, ovarian cancer epithelial cells and ovarian tumour cell lines. Basal SLIT2, SLIT3, ROBO1, ROBO2 and ROBO4 expression was lower in primary cultures of ovarian cancer epithelial cells when compared to normal OSE (P<0.05) and in poorly differentiated SKOV-3 cells compared to the more differentiated PEO-14 cells (P<0.05). Cortisol reduced the expression of certain SLITs and ROBOs in normal OSE and PEO-14 cells (P<0.05). Furthermore blocking SLIT/ROBO activity reduced apoptosis in both PEO-14 and SKOV-3 tumour cells (P<0.05). Interestingly SLIT/ROBO expression could be increased by reducing the expression of the glucocorticoid receptor using siRNA (P<0.05). Overall our findings indicate that in the post-ovulatory phase one role of cortisol may be to temporarily inhibit SLIT/ROBO expression to facilitate regeneration of the OSE. Therefore this pathway may be a target to develop strategies to manipulate the SLIT/ROBO system in ovarian cancer.

Ovarian epithelial-stromal interactions: role of interleukins 1 and 6

Ovarian epithelial cancer is the most lethal gynecologic malignancy. The high mortality is attributed to the fact that most cases typically present in late stage when ovarian cancer (OC) has already spread beyond the ovary. Ovarian epithelial cancer cells are shed into intraperitoneal ascites and easily disseminate throughout the peritoneal cavity with preferential metastasis to the omentum, peritoneum, and local organs. Understanding how ovarian epithelial cells interact with and modulate their microenvironment can provide insight into the molecular mechanism(s) involved with malignant transformation and progression which may eventually identify novel diagnostic, prognostic, and therapeutic targets. The objective of this paper is to provide a brief consideration of ovarian surface epithelial-stromal interactions in regard to normal physiological function and tumor progression as influenced by two potentially key interleukins, interleukins-1 (IL-1) and -6 (IL-6), present in the microenvironment. Lastly, we will consider the clinical implications of IL-1 and IL-6 for OC patients.

Direct actions of ACTH on ovarian function of pseudopregnant rabbits

The present study sought to assess whether the receptors for adrenocorticotropic hormone (ACTH), MC2R, and for glucocorticoid (GR) are expressed in corpora lutea (CL) of pseudopregnant rabbits and whether ACTH and cortisol exert any direct action on luteal function. By immunohistochemistry, positive reaction for MC2R and GR was detectable within luteal cells of CL. The MC2R mRNA levels were five-fold less abundant in day 9 than in day 4 CL (P<0.01). At both stages, ACTH agonist (ACTH 1-24) increased progesterone and prostaglandin (PG) E(2) (PGE(2)) (P<0.01), but reduced PGF(2α) releases (P<0.01) in vitro. ACTH 1-24 injection increased plasma cortisol levels within 4h (P<0.01), but decreased (P<0.01) progesterone 24h later and for the following two days. ACTH administration to estrous rabbits caused a transitory increase in blood progesterone concentrations (P<0.01). Daily injections of ACTH did not modify progesterone profile following ovulation. In conclusion, ACTH directly up-regulates CL progesterone production in vitro via MC2R, but indirectly hampers luteal function via cortisol-GR associated mechanism.

Interaction of adenosine 3',5'-cyclic monophosphate and tumor necrosis factor-alpha on serum amyloid A3 expression in mouse granulosa cells: dependence on CCAAT-enhancing binding protein-beta isoform

TNFalpha is an inflammatory-related cytokine that has inhibitory effects on gonadotropin- and cAMP-stimulated steroidogenesis and folliculogenesis. Because ovulation is an inflammatory reaction and TNF specifically induces serum amyloid A3 (SAA3) in mouse granulosa cells, the effect of cAMP on TNF-induced SAA3 promoter activity, mRNA and protein was investigated. Granulosa cells from immature mice were cultured with TNF and/or cAMP. TNF increased SAA3 promoter activity, mRNA, and protein, which were further increased by cAMP. cAMP alone increased SAA3 promoter activity, but SAA3 mRNA and protein remained undetectable. Thus, there appeared to be different mechanisms by which TNF and cAMP regulated SAA3 expression. SAA3 promoters lacking a nuclear factor (NF)-kappaB-like site or containing its mutant were not responsive to TNF but were responsive to cAMP. Among four CCAAT-enhancing binding protein (C/EBP) sites in the SAA3 promoter, the C/EBP site nearest the NF-kappaB-like site was required for TNF-induced SAA3. The C/EBP site at -75/-67 was necessary for responsiveness to cAMP. Dominant-negative C/EBP and cAMP response element-binding protein or short interfering RNA of C/EBPbeta blocked TNF- or cAMP-induced SAA3 promoter activity. The combination of TNF and cAMP increased C/EBPbeta protein above that induced by TNF or cAMP alone. Thus, cAMP in combination with TNF specifically induced C/EBPbeta protein, leading to enhanced SAA3 expression but requiring NF-kappaB in mouse granulose cells. In addition, like TNF, SAA inhibited cAMP-induced estradiol accumulation and CYP19 levels. These data indicate SAA may play a role in events occurring during the ovulation process.

Programming of offspring sex ratios by maternal stress in humans: assessment of physiological mechanisms using a comparative approach

Sex ratio adjustment has become a hot topic in ecology and evolutionary biology, as documentations of sex ratio skews are numerous, and include examples in diverse animal species. Over the past several decades, scientists have repeatedly debated whether human sex ratios also significantly deviate toward one sex or the other based on environmental or social conditions. An increasing number of studies supports the idea that exposure to stressful conditions can influence the sexes of offspring produced by humans, a majority of which document significantly fewer males after exposure to adverse conditions such as severe life events, economic disruption, or natural disasters. From a comparative standpoint, these findings are similar to studies in non-human mammals and other vertebrate species showing a bias toward females during times of stress. However, the mechanisms by which stress-related biases in the offspring sex ratio may occur remain elusive, and the involvement of glucocorticoids indicating a true influence of stress itself remains unstudied. Here, I review the evidence that stressful events induce sex ratio adjustment in humans. Additionally, I discuss the possibility for glucocorticoid mediation of sex ratio adjustment and the potential reproductive stages during which stress-induced sex ratio adjustment may occur in humans and other mammals.

The SLIT-ROBO pathway: a regulator of cell function with implications for the reproductive system

The secreted SLIT glycoproteins and their Roundabout (ROBO) receptors were originally identified as important axon guidance molecules. They function as a repulsive cue with an evolutionarily conserved role in preventing axons from migrating to inappropriate locations during the assembly of the nervous system. In addition the SLIT-ROBO interaction is involved in the regulation of cell migration, cell death and angiogenesis and, as such, has a pivotal role during the development of other tissues such as the lung, kidney, liver and breast. The cellular functions that the SLIT/ROBO pathway controls during tissue morphogenesis are processes that are dysregulated during cancer development. Therefore inactivation of certain SLITs and ROBOs is associated with advanced tumour formation and progression in disparate tissues. Recent research has indicated that the SLIT/ROBO pathway could also have important functions in the reproductive system. The fetal ovary expresses most members of the SLIT and ROBO families. The SLITs and ROBOs also appear to be regulated by steroid hormones and regulate physiological cell functions in adult reproductive tissues such as the ovary and endometrium. Furthermore several SLITs and ROBOs are aberrantly expressed during the development of ovarian, endometrial, cervical and prostate cancer. This review will examine the roles this pathway could have in the development, physiology and pathology of the reproductive system and highlight areas for future research that could further dissect the influence of the SLIT/ROBO pathway in reproduction.

Dexamethasone-induced cardioprotection: a role for the phosphatase MKP-1?

AIMS

Previous studies suggested that p38 MAPK activation during sustained myocardial ischaemia and reperfusion was harmful. We hypothesize that attenuation of p38MAPK activity via dephosphorylation by the dual-specificity phosphatase MKP-1 should be protective against ischaemia/reperfusion injury. Since the glucocorticoid, dexamethasone, induces the expression of MKP-1, the aim of this study was to determine whether upregulation of this phosphatase by dexamethasone protects the heart against ischaemia/reperfusion injury.

MAIN METHODS

Male Wistar rats were treated with dexamethasone (3 mg/kg/day ip) for 10 days, before removal of the hearts for Western blot (ip Dex-P) or perfusion in the working mode (ip Dex+P). Hearts were subjected to 20 min global or 35 min regional ischaemia (36.5 degrees C) and 30 or 120 min reperfusion. In a separate series, dexamethasone (1 microM) was added to the perfusate for 10 min (Pre+Dex) before or after (Rep+Dex) ischaemia.

KEY FINDINGS

Dexamethasone, administered intraperitoneally or added directly to the perfusate, significantly improved post-ischaemic functional recovery and reduced infarct size compared to untreated controls (p<0.05). These were associated with enhanced up-regulation of MKP-1 protein expression (arbitrary units (mean+/-SD): Untreated: 1; ip Dex-P: 2.59+/-0.22; ip Dex+P: 1.51+/-0.22; Pre+Dex: 4.11+/-0.73, Rep+15'Dex: 1.51+/-0.14; untreated vs. all groups, p<0.05) and attenuation of p38 MAPK activation (p<0.05) in all dexamethasone-treated groups, except for Rep+10'Dex. ERK and PKB/Akt activation were unchanged.

SIGNIFICANCE

Dexamethasone-induced cardioprotection was associated with upregulation of the phosphatase MKP-1 and inactivation of pro-apoptotic p38 MAPK.

Mechanisms involved in tissue-specific apopotosis regulated by glucocorticoids

Physiological cell turnover is under the control of a sharp and dynamic balance of different homeostatic mechanisms such as the equilibrium between cell proliferation and cell death. These mechanisms play an important role in maintaining normal tissue function and architecture. It is well known that apoptosis is the prevalent mode of physiological cell loss in most tissues. Steroid hormones like glucocorticoids have been identified as key signals controlling cell turnover by modulating programmed cell death in a tissue- and cell-specific manner. In this sense, several reports have demonstrated that glucocorticoids are able to induce apoptosis in cells of the hematopoietic system such as monocytes, macrophages, and T lymphocytes. In contrast, they protect against apoptotic signals evoked by cytokines, cAMP, tumor suppressors, in glandular cells such as the mammary gland epithelia, endometrium, hepatocytes, ovarian follicular cells, and fibroblasts. Although several studies have provided significant information on hormone-dependent apoptosis in an specific tissue, a clearly defined pathway that mediates cell death in response to glucocorticoids in different cell types is still misunderstood. The scope of this review is held to those mechanisms by which glucocorticoids control apoptosis, emphasizing tissue-specific expression of genes that are involved in the apoptotic pathway.

Cortisol is a suppressor of apoptosis in bovine corpus luteum

Glucocorticoid (GC) acts as a modulator of physiological functions in several organs. In the present study, we examined whether GC suppresses luteolysis in bovine corpus luteum (CL). Cortisol (an active GC) reduced the mRNA expression of caspase 8 (CASP8) and caspase 3 (CASP3) and reduced the enzymatic activity of CASP3 and cell death induced by tumor necrosis factor (TNF) and interferon gamma (IFNG) in cultured bovine luteal cells. mRNAs and proteins of GC receptor (NR3C1), 11beta-hydroxysteroid dehydrogenase type 1 (HSD11B1), and HSD11B2 were expressed in CL throughout the estrous cycle. Moreover, the protein expression and the enzymatic activity of HSD11B1 were high at the early and the midluteal stages compared to the regressed luteal stage. These results suggest that cortisol suppresses TNF-IFNG-induced apoptosis in vitro by reducing apoptosis signals via CASP8 and CASP3 in bovine CL and that the local increase in cortisol production resulting from increased HSD11B1 at the early and midluteal stages helps to maintain CL function by suppressing apoptosis of luteal cells.

Role of luteal glucocorticoid metabolism during maternal recognition of pregnancy in women

The human corpus luteum (hCL) is an active, transient, and dynamic endocrine gland. It will experience extensive tissue and vascular remodeling followed by 1) demise of the whole gland without any apparent scarring or 2) maintenance of structural and functional integrity dependent on conceptus-derived human chorionic gonadotropin (hCG). Because cortisol has well-characterized roles in tissue remodeling and repair, we hypothesized that it may have a role in controlling luteal dissolution during luteolysis and would be locally produced toward the end of the luteal cycle. Glucocorticoid-metabolizing enzymes [11beta-hydroxysteroid dehydrogenase (11betaHSD) types 1 and 2] and the glucocorticoid receptor (GR) were assessed in hCL and cultures of luteinized granulosa cells (LGC) using immunofluorescence and quantitative RT-PCR. Furthermore, the effect of cortisol on steroidogenic cell survival and fibroblast-like cell activity was explored in vitro. The hCL expressed 11betaHSD isoenzymes in LGC and nuclear GR in several cell types. hCG up-regulated the expression and activity of 11betaHSD type 1 (P < 0.05) and down-regulated type 2 enzyme (P < 0.05) in vitro and tended to do the same in vivo. Cortisol increased the survival of LGC treated with RU486 (P < 0.05) and suppressed the activity of a proteolytic enzyme associated with luteolysis in fibroblast-like cells (P < 0.05). Our results suggest that, rather than during luteolysis, it is luteal rescue with hCG that is associated with increased local cortisol generation by 11betaHSD type 1. Locally generated cortisol may therefore act on the hCL through GR to have a luteotropic role in the regulation of luteal tissue remodeling during maternal recognition of pregnancy.

Thyroid hormone signaling in human ovarian surface epithelial cells

CONTEXT

Ovarian surface epithelial (OSE) cells express multiple nuclear hormone receptor genes, including those encoding thyroid hormone and estrogen receptors (TR and ER, respectively). Ovarian cancer is hormone-dependent, and epidemiological evidence links hyperthyroidism, inflammation of the ovarian surface, and increased risk of ovarian cancer.

OBJECTIVE

The objective of this study was to assess T3 action on human OSE cells in vitro, asking 1) is there evidence for (pre)receptor control, 2) is T3 inflammatory, and 3) does T3 affect ER expression?

DESIGN

Immunohistochemical analysis of fixed human ovaries and in vitro analysis of human OSE primary cell cultures were performed.

PATIENTS

Twelve women aged 29-50 yr (median, 41 yr) undergoing elective gynecological surgery for nonmalignant conditions were studied.

RESULTS

Messenger RNA transcripts for TRalpha1, TRalpha2, TRbeta1, and T3 activating deiodinase 2 and inactivating deiodinase 3 were present in primary OSE cell cultures by RT-PCR. TRalpha and TRbeta proteins were also localized to intact OSE by immunohistochemistry. Treatment of OSE cell cultures for 24 h with T3 caused dose-dependent mRNA expression of inflammation-associated genes: cyclooxygenase-2, matrix metalloproteinase-9, and 11betahydroxysteroid dehydrogenase type 1, determined by quantitative RT-PCR. Finally, treatment with T3 dose dependently stimulated ERalpha mRNA expression without affecting ERbeta1 or ERbeta2.

CONCLUSION

The ovarian surface is a potential T3 target. T3 exerts direct inflammatory effects on OSE cell function in vitro. OSE cell responses to T3 include increased expression of ERalpha mRNA, which encodes the ER isoform most strongly associated with ovarian cancer. This could help explain suggested epidemiological links between hyperthyroidism and ovarian cancer.

Glucocorticoids repress bcl-X expression in lymphoid cells by recruiting STAT5B to the P4 promoter

The bcl-X gene plays a critical role in apoptosis. Six different isoforms generated by tissue-specific promoter usage and alternative splicing were described. Some of them exert opposite effects on cell death. In mammary epithelial cells glucocorticoids induce bcl-X expression and increase the ratio bcl-X(L) (antiapoptotic)/bcl-X(S) (apoptotic) by activating P4 promoter, which contains two hormone response elements. Here we show that, on mouse thymocytes and T lymphocyte derivative S49 cells, glucocorticoids inhibited transcription from P4 and decreased the ratio bcl-X(L)/bcl-X(S) favoring apoptosis. Upon hormonal treatment, glucocorticoid receptor (GR), steroid receptor coactivator-1, and RNA polymerase II were transiently recruited to P4 promoter, whereas STAT5B was also recruited but remained bound. Concomitant with the release of GR, silencing mediator for retinoic acid receptor and thyroid hormone receptor and histone deacetylase 3 were recruited, histone H3 was deacetylated, and RNA polymerase II left the promoter. Inhibition of STAT5 activity reverted glucocorticoid repression to activation of transcription and was accompanied by stable recruitment of GR and RNA polymerase II to P4.

Mineralocorticoid Synthesis During the Periovulatory Interval in Macaques1

Ovulation and luteal formation in primates are associated with the sustained synthesis of progesterone. The observed high intrafollicular concentrations of progesterone during the periovulatory interval raise the possibility that this steroid serves as a precursor for mineralocorticoids. The aim of this study was to determine if mineralocorticoids are synthesized by the luteinizing macaque follicle during controlled ovarian stimulation cycles in which follicular fluid and granulosa cell aspirates were obtained before or after an ovulatory hCG bolus. Follicular fluid concentrations of progesterone and 17alpha-hydroxyprogesterone increased within 3 h of an ovulatory hCG bolus. Their respective metabolites, 11-deoxycorticosterone (DOC) and 11-deoxycortisol, were not detectable before an ovulatory stimulus and increased starting at 6 h after hCG, while corticosterone and aldosterone were undetectable. Cortisol was present before and after hCG administration and had increased 2-fold at 24 h after an ovulatory stimulus. The expression of 21-hydroxylase (CYP21A2) mRNA increased within 3 h of hCG administration, while 11beta-hydroxylase-1 (CYP11B1) and 11beta-hydroxylase-2 (CYP11B2) mRNAs were not detectable. 11beta-Hydroxysteroid dehydrogenase-1 (HSD11B1) mRNA had increased at 12 h after hCG administration, and 11beta-hydroxysteroid dehydrogenase-2 (HSD11B2) had decreased by 3 h after hCG administration. Mineralocorticoid receptor mRNA levels did not change following hCG administration, while glucocorticoid receptor mRNA levels increased in response to an ovulatory stimulus. Treatment of granulosa cells with the mineralocorticoid receptor antagonist spironolactone blocked hCG-induced progesterone synthesis in vitro. These data indicate that macaque granulosa cells can synthesize mineralocorticoids in response to an ovulatory stimulus and that the mineralocorticoid receptor plays a key role in steroid synthesis associated with luteinization of macaque granulosa cells.

Endometriosis as a model for inflammation–hormone interactions in ovarian and breast cancers

Chronic inflammation has been implicated in a variety of cancers. In this review, we consider associations between endometriosis and cancers both local (ovarian) and distant (breast). We review the epidemiological data linking endometriosis to ovarian and breast cancers. We then consider evidence for a role for sex steroid hormones and for inflammation in the aetiology of each of these cancers. Finally, we consider that endometriosis may promote alterations in sex steroid hormones and inflammatory mediators. A possible explanation for the association between endometriosis and these reproductive cancers may then be local and systemic enhancement of aberrant inflammatory and hormonal mediators. If this hypothesis is true, endometriosis may need to be considered as a risk factor for ovarian and breast cancers, triggering increasingly intensive surveillance. Moreover, treatments for endometriosis may require consideration of the impact on long-term cancer risk.

11Beta-hydroxysteroid dehydrogenases in human endometrium

Key reproductive events, such as menstruation and implantation, are considered to be inflammatory processes and glucocorticoids act as anti-inflammatory agents. The balance of expression of types 1 and 2 11beta-hydroxysteroid dehydrogenases (11betaHSD) controls the availability of cortisol to bind to the glucocorticoid receptor (GR) and mineralocorticoid receptor (MR). Expression profiles of glucocorticoid-metabolising enzymes and their cognate receptors have been characterized in the reproductive tract. We propose that factors that peripherally promote glucocorticoid action are part of an anti-inflammatory response to tissue remodelling in human endometrium. Protein and mRNA expression in endometrium were investigated using immunohistochemistry and quantitative real-time PCR. There was up-regulated expression of 11betaHSD-1 at menstruation and in first trimester decidua. 11BetaHSD-2 and GR were expressed across the cycle. The MR expression pattern across the cycle and in decidua implies progesterone may also play a regulatory role. The precise roles and interactions of these proteins require further investigation.

Incessant ovulation, inflammation and epithelial ovarian carcinogenesis: revisiting old hypotheses

Epithelial ovarian cancer (EOC) is often a lethal disease because in many cases early symptoms go undetected. Although research proceeds apace, as yet there are few reliable and specific biomarkers for the early stages of the disease. EOC is an umbrella label for a highly heterogeneous collection of cancers, which includes tumours of low malignant potential, serous cystadenomas, mucinous and clear cell carcinomas, all of which are likely to arise from a number of epithelial cell types and a variety of progenitor lesions. Many, but not all types of EOC are thought to arise from the cells lining ovarian inclusion cysts. In this review, we discuss the hypotheses that have driven our ideas on epithelial ovarian carcinogenesis and examine the morphological and genetic evidence for pathways to EOC. The emergence of laser-capture microdissection and expression profiling by microarray technologies offers the promise of defining these pathways more accurately, as well as providing us with the tools for earlier diagnosis.

Steroid signalling in the ovarian surface epithelium

Human ovarian surface epithelium (HOSE) undergoes serial injury-repair with each ovulation, which is probably why most ovarian epithelial cancers arise there. Considering the proposed inflammatory aetiology of ovarian cancer, anti-inflammatory steroid signalling might be vital for HOSE regulation. HOSE cells express hydroxysteroid dehydrogenase (HSD) enzymes that undertake prereceptor metabolism of bioinert steroidogenic precursors formed elsewhere in the body. Ovulation-associated cytokines activate anti-inflammatory cortisol from precursor cortisone in HOSE cells owing to up-regulation of the gene encoding 11betaHSD type 1 (HSD11B1) in vitro. Cortisol further enhances its own formation and action through augmentation of cytokine-induced HSD11B1 and glucocorticoid receptor gene expression. Understanding this feed-forward signalling process has implications for the improved diagnosis and treatment of inflammation-associated reproductive disease states such as ovarian cancer.

Inflammation-associated gene expression is altered between normal human ovarian surface epithelial cells and cell lines derived from ovarian adenocarcinomas

Ovulation is believed to contribute to the development of ovarian cancers that derive from the ovarian surface epithelium (OSE). The process of ovulation is synonymous with inflammation and inflammatory cytokines such as interleukin-1α (IL-1α) have recently been shown to induce both inflammatory and anti-inflammatory responses in human OSE (HOSE) cells. In this study we directly compared levels of IL-1α-induced gene expression by analysing the levels of 11β-hydroxysteroid dehydrogenase (11βHSD) types 1 (11βHSD-1) and 2 (11βHSD-2), cyclooxygenase-2 (COX-2), IL-1 receptor (IL-1R) and glucocorticoid receptor α (GRα) mRNA between normal HOSE cells and cell lines derived from poorly differentiated (SKOV-3, BG-1, PEO-4) and well-differentiated (PEO-14) ovarian adenocarcinoma. In HOSE cell cultures, and to a lesser extent PEO-14 cells, the basal mRNA levels of COX-2 and 11βHSD-1 were relatively high and further shown to be induced in response to IL-1α (for HOSE cells; >20-fold, P<0.05 and PEO-14 cells; >3fold, P<0.05). However, whereas HOSE cells expressed a low level of 11βHSD-2 mRNA that was only mildly responsive to IL-1α (1.3-fold, P<0.001), all cell lines exhibited a higher basal level of 11βHSD-2 mRNA that was in some cases further stimulated in PEO-4 cells (five-fold; P<0.05) or suppressed in SKOV-3 cells (two-fold; P<0.01) in response to IL-1α. All cells tested expressed IL-1R and, with the exception of BG-1, GRα. These results indicate that cell lines derived from ovarian cancers have lost the ability to respond normally to inflammatory cytokines such as IL-1α. The finding that normal OSE cells, in contrast to cell lines derived from patients with ovarian adenocarcinoma, abundantly express 11βHSD-1 mRNA but are essentially devoid of 11βHSD-2 mRNA supports the concept that the pattern of 11βHSD isoform gene expression is a defining feature of neoplastic cellular transformation, which might have particular relevance to the ovary.

In Vivo Evidence that Local Cortisol Production Increases in the Preovulatory Follicle of the Cow

The aim of the present in vivo study was to monitor real-time fluctuations of cortisol (Cr) in the wall of preovulatory follicles using a microdialysis system (MDS) implanted in the theca layer as well as changes in ovarian venous plasma (OVP) and jugular venous plasma (JVP). Seven cows were superovulated using FSH and prostaglandin F2alpha injections. Dialysis capillary membranes were surgically implanted into the theca layer of mature follicles and connected to a microdialysis system. Fractions of the perfusates were collected from Day -1 (Day 0=LH surge) to Day 3. No difference in the concentrations of Cr between JVP and OVP was detected throughout the experiment. Circulating concentrations of Cr ranged from 20 to 35 ng/ml 8 h after surgery in ovulatory and anovulatory cows. In five ovulatory cows, the Cr concentration decreased to basal levels (<10 ng/ml) between 12 and 24 h after surgery, however, two anovulatory cows retained high Cr levels (>10 ng/ml) up to 42 h after surgery. There was a clear increase in the local concentration of Cr from 13.3+/-2.1 pg/ml at -24 h to 27.5+/-1.7 pg/ml at 0 h (peak of the LH surge) within the wall of ovulatory follicles. This increase was not detected in anovulatory follicles. This transient increase in Cr occurred only in the follicle wall, but not in the OVP or JVP, indicating that the presence of a local regulatory mechanism for Cr production/conversion in ovulatory follicles, and this mechanism may modulate the inflammatory-like reaction induced by LH surge in the follicle wall. The present results demonstrate that the glucocorticoid environment in the follicular wall adjusts at the local level in bovine ovulatory follicles. This mechanism may protect follicles from the adverse effects of glucocorticoid, and it may prevent excess inflammatory reactions associated with ovulation by temporarily increasing local concentrations of glucocorticoid, thus forming an integral part of the regulatory mechanism in ovarian physiology.