Regulation of oocyte and cumulus cell interactions by intermedin/adrenomedullin 2

Reduced PATL2 Impairs the Proliferation of Ovarian Granulosa Cells by Decreasing ADM2 Expression in Patients with PCOS

It is recognized that PCOS patients are often accompanied with aberrant follicular development, which is an important factor leading to infertility in patients. However, the relevant regulatory mechanisms of abnormal follicular development are not well understood. In the present study, by collecting human ovarian granulosa cells (GCs) from PCOS patients who underwent in vitro fertilization (IVF), we found that the proliferation ability of GCs in PCOS patients was significantly reduced. Surprisingly, PATL2 and adrenomedullin 2 (ADM2) were obviously decreased in the GCs of PCOS patients. To further explore the potential roles of PATL2 and ADM2 on GC, we transfected PATL2 siRNA into KGN cells to knock down the expression of PATL2. The results showed that the growth of GCs remarkably repressed after knocking down the PATL2, and ADM2 expression was also weakened. Subsequently, to study the relationship between PATL2 and ADM2, we constructed PATL2 mutant plasmid lacking the PAT construct and transfected it into KGN cells. The cells showed the normal PATL2 expression, but attenuated ADM2 expression and impaired proliferative ability of GCs. Finally, the rat PCOS model experiments further confirmed our findings in KGN cells. In conclusion, our study suggests that PATL2 promoted the proliferation of ovarian GCs by stabilizing the expression of ADM2 through "PAT" structure, which is beneficial to follicular development, whereas, in the ovary with polycystic lesions, reduction of PATL2 could result in the decreased expression of ADM2, subsequently weakened the proliferation ability of GCs and finally led to the occurrence of aberrant follicles.

Identification of genes involved in chicken follicle selection by ONT sequencing on granulosa cells

In chickens, follicle selection is an important process affecting laying traits, which is characterized by the differentiation of granulosa cells and the synthesis of progesterone by granulosa cells from hierarchical follicles. By using Oxford Nanopore Technologies (ONT) approach, we compared the transcriptomes of granulosa cells between pre-hierarchical (Pre-GCs) and hierarchical follicles (Post-GCs) to identify genes underlying chicken follicle selection. A total of 2,436 differentially expressed genes (DEGs), 3,852 differentially expressed transcripts (DETs) and 925 differentially expressed lncRNA transcripts were identified between chicken Pre-GCs and Post-GCs. For all of the significant DETs, the alternative 3'splice sites (A3) accounted for a maximum of 23.74% of all alternative splicing events. Three DETs of the 7-dehydrocholesterol reductase gene (DHCR7) named as T1, T3, and T4, differing in 5'untranslated regions (UTRs), increased in Post-GCs with different folds (T1: 1.83, T3: 2.42, T4: 5.06). The expression of the three DHCR7 transcripts was upregulated by estrogen in a dose-dependent manner, while was downregulated by bone morphogenetic protein 15 (BMP15) and transforming growth factor-beta 1 (TGF-β1). Follicle-stimulating hormone (FSH) and bone morphogenetic protein 4 (BMP4) promoted the expression of the three DHCR7 transcripts in Pre-GCs at lower concentrations, while repressed their expression at higher concentrations. The data from this study may provide a reference for better understanding of the genetic mechanisms underlying follicle selection in chicken and other poultry species.

IMD/ADM2 operates as a secretory factor that controls cumulus-oocyte complexes (COCs) conformation for oocytes in vitro maturation

During in vitro maturation (IVM), the compact structure of cumulus-oocyte complexes (COCs) is vital for oocyte competence acquisition. Intermedin/Adrenomedullin-2 (IMD/ADM2) binds to the receptor RAMP (1, 2, or 3):CLR. Recently, it was demonstrated that IMD/ADM2 stimulates oocyte competence and improves bovine embryo quality. Therefore, this study aimed to examine the IMD/ADM2 as a secretory factor controlling COCs conformation for oocyte maturation. The results showed that traditional M-CDM medium induced in COCs the Imd/Adm2 gene expression during IVM and produced IMD/ADM2 peptide secretion. Furthermore, after IVM, in the oocytes, the expression of ramps (1, 2, or 3) and clr was demolished, and RAMPs and CLR proteins were decreased, with a negative Pearson correlation. These results suggest that RAMPs and CLR are synthesized and stored during oocyte maturation. Supplementing the M-CDM with α-RAMP1 or α-IMD/ADM2 antibodies elicits a negative effect (P < 0.05) in COCs compaction. Blocking the IMD/ADM2 signaling pathway with any α-RAMPs or α-CLR antibodies produces a similar lower yield of oocytes in metaphase II (P > 0.05) but was lower than control culture medium (P < 0.05). In conclusion, when COCs are cultured with M-CDM, the IMD/ADM2 becomes expressed and secreted. In turn, it acts as a ligand preferentially to RAMP1:CLR or RAMP3:CLR, present in cumulus cells and oocytes. Sequentially, COCs compact structure is conformed to promote an adequate bidirectional communication that conduces the oocytes' maturation.

Oocyte-specific disruption of adrenomedullin 2 gene enhances ovarian follicle growth after superovulation

BACKGROUND

Adrenomedullin 2 (ADM2), adrenomedullin (ADM), and calcitonin gene-related peptides (α- and β-CGRPs) signal through heterodimeric calcitonin receptor-like receptor/receptor activity-modifying protein 1, 2 and 3 (CLR/RAMP1, 2 and 3) complexes. These peptides are important regulators of neurotransmission, vasotone, cardiovascular development, and metabolic homeostasis. In rodents, ADM is essential for regulating embryo implantation, fetal-placental development, and hemodynamic adaptation during pregnancy. On the other hand, ADM2 was shown to affect vascular lumen enlargement, and cumulus cell-oocyte complex (COC) communication in rodent and bovine ovarian follicles. To investigate whether oocyte-derived ADM2 plays a physiological role in regulating ovarian folliculogenesis, we generated mice with oocyte-specific disruption of the Adm2 gene using a LoxP-flanked Adm2 transgene (Adm2 loxP/loxP) and crossed them with Zp3-Cre mice which carry a zona pellucida 3 (Zp3) promoter-Cre recombinase transgene.

RESULTS

While heterozygous Adm2 +/-/Zp3-Cre and homozygous Adm2 -/-/Zp3-Cre mice were fertile, Adm2 disruption in oocytes significantly increased the number of ovulated oocytes following a superovulation treatment. Oocyte-specific Adm2 disruption also significantly impaired the developmental capacity of fertilized eggs and decreased the size of the corpus luteum following superovulation, perhaps due to a reduction of ovarian cyclin D2-associated signaling.

CONCLUSIONS

The disruption of intrafollicular ADM2 signaling leads to follicular dysfunction. These data suggested that oocyte-derived ADM2 plays a facilitative role in the regulation of hormonal response and follicle growth independent of the closely related ADM and CGRP peptides, albeit in a subtle manner.

IMD/ADM21-47, a factor that improves embryo quality

Starting in vitro fertilization process with competent oocytes that may endure first cellular divisions is a critical step for obtaining an embryo. To obtain in vitro competent oocytes, culture conditions should emulate the in vivo microenvironment as close as possible. With the aim of improving the in vitro culture medium, the present study evaluated the IMD/ADM2_1-47 peptide as a factor that promotes oocyte competence and improves embryo quality in bovine systems. The culture supplemented with 153 μg/mL of IMD/ADM2_1-47 was correlated with the production of healthy oocytes in metaphase II (MII) stage in compacted cumulus-oocyte complexes (COC) with a decrease of BAX/BCL-2 to mRNA ratio and a reduction of late apoptosis by TUNEL in MII oocytes. In addition to this, treatment with IMD/ADM2_1-47 caused cAMPi level to be constant over time, and the cAMPi level kept increasing until 6 h. COC supplementation with 153 μg/mL of IMD/ADM2_1-47 increased the blastocyst production rate two-fold in comparison with control conditions. Only embryos from COC treatment with this peptide were capable of developing blastocysts in stage-6 grade I; compared with the control culture, it was the treatment with the greater number of blastocysts stage-5; these are characteristics of good quality blastocysts.

Ligands, Receptors, and Transcription Factors that Mediate Inter-Cellular and Intra-Cellular Communication during Ovarian Follicle Development

Reliably producing a competent oocyte entails a deeper comprehension of ovarian follicle maturation, a very complex process that includes meiotic maturation of the female gamete, the oocyte, together with the mitotic divisions of the hormone-producing somatic cells. In this report, we investigate murine ovarian folliculogenesis in vivo using publicly available time-series microarrays from primordial to antral stage follicles. Manually curated protein interaction networks were employed to identify autocrine and paracrine signaling between the oocyte and the somatic cells (granulosa and theca cells) at multiple stages of follicle development. We established plausible protein-binding interactions between expressed genes that encode secreted factors and expressed genes that encode cellular receptors. Some computationally identified signaling interactions are well established, such as the paracrine signaling from the oocyte to the somatic cells through the oocyte-secreted growth factor Gdf9, while others are novel connections in term of ovarian folliculogenesis, such as the possible paracrine connection from somatic-secreted factor Ntn3 to the oocyte receptor Neo1. Additionally, we identified several of the likely transcription factors that might control the dynamic transcriptome during ovarian follicle development, noting that the YAP/TAZ signaling pathway is very active in vivo. This novel dynamic model of signaling and regulation can be employed to generate testable hypotheses regarding follicle development that could be validated experimentally, guiding the improvement of culture media to enhance in vitro ovarian follicle maturation and possibly novel therapeutic targets for reproductive diseases.

PATL2 is a key actor of oocyte maturation whose invalidation causes infertility in women and mice

The genetic causes of oocyte meiotic deficiency (OMD), a form of primary infertility characterised by the production of immature oocytes, remain largely unexplored. Using whole exome sequencing, we found that 26% of a cohort of 23 subjects with OMD harboured the same homozygous nonsense pathogenic mutation in PATL2, a gene encoding a putative RNA‐binding protein. Using Patl2 knockout mice, we confirmed that PATL2 deficiency disturbs oocyte maturation, since oocytes and zygotes exhibit morphological and developmental defects, respectively. PATL2's amphibian orthologue is involved in the regulation of oocyte mRNA as a partner of CPEB. However, Patl2's expression profile throughout oocyte development in mice, alongside colocalisation experiments with Cpeb1, Msy2 and Ddx6 (three oocyte RNA regulators) suggest an original role for Patl2 in mammals. Accordingly, transcriptomic analysis of oocytes from WT and Patl2^−/− animals demonstrated that in the absence of Patl2, expression levels of a select number of highly relevant genes involved in oocyte maturation and early embryonic development are deregulated. In conclusion, PATL2 is a novel actor of mammalian oocyte maturation whose invalidation causes OMD in humans.

Follicular Fluid Levels of Adrenomedullin 2, Vascular Endothelial Growth Factor and its Soluble Receptors Are Associated with Ovarian Response During ART Cycles

Introduction Adrenomedullin 2 (ADM2) and vascular endothelial growth factor (VEGF) affect ovarian function, especially angiogenesis and follicular development. The actions of VEGF can be antagonized by its soluble receptors, soluble Fms-like tyrosine kinase-1 (sFlt-1) and soluble VEGF receptor 2 (sVEGFR-2), as they decrease its free form. In the present study, we evaluated the relationship between follicular fluid (FF) levels of AMD2, VEGF and its soluble receptors, and ICSI outcomes.

Materials and Methods ICSI cycle outcomes were evaluated and FF levels of VEGF, sFlt-1, sVEGFR-2 and ADM2 were determined using ELISA kits.

Results FF levels of ADM2, VEGF, and sVEGFR-2 were significantly higher in non-responders compared to other ovarian response groups (p < 0.05). There were significant correlations between ADM2, VEGF and sVEGFR-2 levels as well as VEGF/sFlt-1 and VEGF/sVEGFR-2 ratios (r = 0.586, 0.482, 0.260, and − 0.366, respectively). Based on the ROC curve, the cutoff value for ADM2 as a non-responder predictor was 348.55 (pg/ml) with a sensitivity of 67.7% and a specificity of 94.6%.

Conclusions For the first time we measured FF ADM2 levels to determine the relationship to VEGF and its soluble receptors. We suggest that ADM2 could be a potential predictive marker for non-responders. Although the exact function of ADM2 in ovarian angiogenesis is not yet understood, our study may shed light on the possible role of ADM2 in folliculogenesis and ovulation.

Protein oligomerization is the biochemical process highly up-regulated in porcine oocytes before in vitro maturation (IVM)

A wide variety of mechanisms controlling oligomerization are observed. The dynamic nature of protein oligomerization is important for bioactivity control. The oocyte must undergo a series of changes to become a mature form before it can fully participate in the processes associated with its function as a female gamete. The growth of oocytes in the follicular environment is accompanied by surrounding somatic cumulus (CCs) and granulosa cells (GCs). It has been shown that oocytes tested before and after in vitro maturation (IVM) differ significantly in the transcriptomic and proteomic profiles. The aim of this study was to determine new proteomic markers for the oligomerization of porcine oocyte proteins that are associated with cell maturation competence. The Affymetrix microarray assay was performed to examine the gene expression profile associated with protein oligomerization in oocytes before and after IVM. In total, 12258 different transcriptomes were analyzed, of which 419 genes with lower expression in oocytes after IVM. We found 9 genes: GJA1, VCP, JUP, MIF, MAP3K1, INSR, ANGPTL4, EIF2AK3, DECR1, which were significantly down-regulated in oocytes after IVM (in vitro group) compared to oocytes analyzed before IVM (in vivo group). The higher expression of genes involved in the oligomerization of the protein before IVM indicates that they can be recognized as important markers of biological activation of proteins necessary for the further growth and development of pig embryos.

Urea influences amino acid turnover in bovine cumulus-oocyte complexes, cumulus cells and denuded oocytes, and affects in vitro fertilization outcome

High-protein diets often lead to an increase in urea concentration in follicular fluid of dairy cows, which may reduce oocyte competence. In the present study, maturation media were supplemented with urea (0, 20, 40 mg/dl), and amino acids (AAs) turnover was evaluated in the 24-h spent media of specimens (cell types), bovine cumulus-oocyte complexes (COCs), cumulus cells (CCs), or denuded oocytes (DOs). The main effects of urea and cell type, and their interaction were significant on the individual turnover (expect threonine, glycine, and tyrosine) and total turnover, depletion, and appearance of AAs. The results showed a high level of urea and DOs increased the depletion of all AAs and that of essential and non-AAs, respectively. Sensitivity analysis revealed the highest sensitivity of isoleucine, lysine, and tryptophan to urea, especially in DOs. Principal component analysis (PCA) evaluated the strong correlations between the turnover of: (1) glutamine, aspartic acid or glycine, and developmental competence and fertilization of COCs; (2) serine, isoleucine, valine or glutamic acid, and cleavage rate of DOs; and (3) serine, glutamine, aspartic acid or alanine, and CCs viability. In conclusion, urea significantly changed the turnover of AAs by COCs, CCs and DOs, and reduced the subsequent developmental competence of bovine oocytes.

Mechanisms controlling germline cyst breakdown and primordial follicle formation

In fetal females, oogonia proliferate immediately after sex determination. The progress of mitosis in oogonia proceeds so rapidly that the incompletely divided cytoplasm of the sister cells forms cysts. The oogonia will then initiate meiosis and arrest at the diplotene stage of meiosis I, becoming oocytes. Within each germline cyst, oocytes with Balbiani bodies will survive after cyst breakdown (CBD). After CBD, each oocyte is enclosed by pre-granulosa cells to form a primordial follicle (PF). Notably, the PF pool formed perinatally will be the sole lifelong oocyte source of a female. Thus, elucidating the mechanisms of CBD and PF formation is not only meaningful for solving mysteries related to ovarian development but also contributes to the preservation of reproduction. However, the mechanisms that regulate these phenomena are largely unknown. This review summarizes the progress of cellular and molecular research on these processes in mice and humans.

"Cell Migration" Is the Ontology Group Differentially Expressed in Porcine Oocytes Before and After In Vitro Maturation: A Microarray Approach

Maturation of cumulus-oocyte complexes (COCs) is crucial for further successful monospermic fertilization, embryo growth, and implantation. All these events are accompanied by proliferation and differentiation of cumulus cells. The migration of COCs to the oviduct after ovulation and the interaction between female gametes and/or embryos with maternal tissues are still poorly recognized on the molecular level. This study was aimed to first demonstrate the mRNA expression profile of cell migration markers during different stages of porcine oocytes maturation and developmental capability in vitro. The COCs were collected from a total of 45 pubertal crossbred Landrace gilts, brilliant cresyl blue (BCB) stained, and analyzed before (n = 150) or after (n = 150) in vitro maturation (IVM). Using the Affymetrix^® Porcine Gene 1.1 ST Array, the expression profile of 12,258 porcine transcripts was examined. We found nine genes involved in cell migration mechanisms, that is, PLD1, KIT, LAMA2, MAP3K1, VEGFA, TGFBR3, INSR, TPM1, and RTN4. These genes were upregulated in porcine oocytes before IVM as compared with post-IVM expression analysis. Moreover, important mechanisms of biological interaction between VEGFA-KIT and VEGFA-INSR were also observed. The upregulation and/or downregulation of selected mRNAs expression after microarray assays was checked and approved by real-time quantitative polymerase chain reaction. We suggest that several genes, including LAMA2 or TPM1, encode proteins participating in the formation of the oocyte's protein architecture such as microtubules and kinetochore reorganization. As the expression of all "migration regulatory genes" investigated in this study was significantly upregulated in oocytes before IVM, we conclude that they may contribute to the maturational capability of porcine oocytes. However, migration potency of COCs is not accompanied by achievement of the MII stage by porcine oocytes in vitro. The investigated genes such as PLD1, KIT, LAMA2, MAP3K1, VEGFA, TGFBR3, INSR, TPM1, and RTN4 may be recognized as a new marker of porcine oocytes maturational competence during in vitro culture.

Biobanking of different body fluids within the frame of IVF-a standard operating procedure to improve reproductive biology research

Purpose

The aim of the present study was to develop a standard operating procedure (SOP) for the collection, transport, and storage of human cumulus cells, follicular fluid, blood serum, seminal plasma, embryo culture supernatant, and embryo culture supernatant control obtained within the IVF process under approved protocols and written informed consent from participating patients. The SOP was developed at the Kinderwunsch Institut Schenk, Dobl, Austria, together with Biobank Graz of the Medical University of Graz, Austria.

Methods

The SOP provides comprehensive details of laboratory procedures and sampling of the different fluids within the IVF process. Furthermore, information on sample coding, references of involved laboratory techniques (e.g., oocyte retrieval with a Steiner-TAN needle), ethical approvals, and biobanking procedures are presented.

Results

The result of the present study is a standard operating procedure.

Conclusions

The SOP ensures a professional way for collection and scientific use of IVF samples by the Kinderwunsch Institut Schenk, Dobl, Austria, and Biobank Graz of the Medical University of Graz, Austria. It can be used as a template for other institutions to unify specimen collection procedures in the field of reproductive health research.

Phosphoramide mustard induces autophagy markers and mTOR inhibition prevents follicle loss due to phosphoramide mustard exposure

Phosphoramide mustard (PM) is an ovotoxic metabolite of cyclophosphamide. Postnatal day 4 Fisher 344 rat ovaries were exposed to vehicle control (1% DMSO) or PM (60μM)±LY294002 or rapamycin for 2 or 4 d. Transmission election microscopy revealed abnormally large golgi apparatus and electron dense mitochondria in PM-exposed ovaries prior to and at the time of follicle depletion. PM exposure increased (P<0.05) mRNA abundance of Bbc3, Cdkn1a, Ctfr, Edn1, Gstp1, Nqo1, Tlr4, Tnfrsfla, Txnrd1 and decreased (P<0.05) Casp1 and Il1b after 4d. PM exposure increased (P<0.1) BECN1 and LAMP, decreased (P<0.1) ABCB1 and did not alter ABCC1 protein. LY294002 did not impact PM-induced ovotoxicity, but decreased ABCC1 and ABCB1 protein. Rapamycin prevented PM-induced follicle loss. These data suggest that the mammalian target of rapamycin, mTOR, may be a gatekeeper of PM-induced follicle loss.

Insights into female germ cell biology: from in vivo development to in vitro derivations

Understanding the mechanisms of human germ cell biology is important for developing infertility treatments. However, little is known about the mechanisms that regulate human gametogenesis due to the difficulties in collecting samples, especially germ cells during fetal development. In contrast to the mitotic arrest of spermatogonia stem cells in the fetal testis, female germ cells proceed into meiosis and began folliculogenesis in fetal ovaries. Regulations of these developmental events, including the initiation of meiosis and the endowment of primordial follicles, remain an enigma. Studying the molecular mechanisms of female germ cell biology in the human ovary has been mostly limited to spatiotemporal characterizations of genes or proteins. Recent efforts in utilizing in vitro differentiation system of stem cells to derive germ cells have allowed researchers to begin studying molecular mechanisms during human germ cell development. Meanwhile, the possibility of isolating female germline stem cells in adult ovaries also excites researchers and generates many debates. This review will mainly focus on presenting and discussing recent in vivo and in vitro studies on female germ cell biology in human. The topics will highlight the progress made in understanding the three main stages of germ cell developments: namely, primordial germ cell formation, meiotic initiation, and folliculogenesis.

Proteomic analysis of human follicular fluid from fertile women

Background

Follicular fluid is a unique biological fluid in which the critical events of oocyte and follicular maturation and somatic cell-germ cell communication occur. Because of the intimate proximity of follicular fluid to the maturing oocyte, this fluid provides a unique window into the processes occurring during follicular maturation. A thorough identification of the specific components within follicular fluid may provide a better understanding of intrafollicular signaling, as well as reveal potential biomarkers of oocyte health for women undergoing assisted reproductive treatment. In this study, we used high and low pH HPLC peptide separations followed by mass spectrometry to perform a comprehensive proteomic analysis of human follicular fluid from healthy ovum donors. Next, using samples from a second set of patients, an isobaric mass tagging strategy for quantitative analysis was used to identify proteins with altered abundances after hCG treatment.

Results

A total of 742 follicular fluid proteins were identified in healthy ovum donors, including 413 that have not been previously reported. The proteins belong to diverse functional groups including insulin growth factor and insulin growth factor binding protein families, growth factor and related proteins, receptor signaling, defense/immunity, anti-apoptotic proteins, matrix metalloprotease related proteins, and complement activity. In a quantitative analysis, follicular fluid samples from age-matched women undergoing in vitro fertilization oocyte retrieval were compared and 17 follicular fluid proteins were found at significantly altered levels (p < 0.05) between pre-hCG and post-hCG samples. These proteins belong to a variety of functional processes, including protease inhibition, inflammation, and cell adhesion.

Conclusions

This database of FF proteins significantly extends the known protein components present during the peri-ovulatory period and provides a useful basis for future studies comparing follicular fluid proteomes in various fertility, disease, and environmental exposure conditions. We identified 17 differentially expressed proteins after hCG treatment and together these data showed the feasibility for defining biomarkers that illuminate how the ovarian follicle microenvironment is altered in various infertility-related conditions.

Electronic supplementary material

The online version of this article (doi:10.1186/s12014-015-9077-6) contains supplementary material, which is available to authorized users.

Adrenomedullin2 (ADM2)/intermedin (IMD) in rat ovary: changes in estrous cycle and pregnancy and its role in ovulation and steroidogenesis

Adrenomedullin2 (ADM2) is reported to facilitate embryo implantation and placental development. Therefore, the current study was undertaken to identify if ADM2 has a functional role in ovary to facilitate its reproductive actions. This study shows that the expression of ADM2 is differentially regulated in rat estrous cycle and that ADM2 increases the synthesis and secretion of 17beta-estradiol accompanied with an increase in the expression of steroidogenic factor 1 (Sf1), estrogen receptor Esr1, and enzymes involved in steroidogenesis in equine chorionic gonadotropin (eCG)-treated rat ovaries. In addition, inhibition of endogenous ADM2 function in eCG-treated immature rats caused impaired ovulation. Furthermore, the mRNA expression of Adm2 and receptor activity modifying protein 3 is higher in the ovary on Day 18 compared to nonpregnant and pregnant rats on Day 22. ADM2-like immunoreactivity is localized in granulosa cells, blood vessels, oocytes, cumulous oophorus, and corpus luteum of pregnant ovaries, suggesting a potential role for ADM2 in the ovary. This is supported by the presence of ADM2-like immunoreactivity in the corpus luteum during pregnancy and a decline in aromatase immunoreactivity in corpus luteum on Day 9 of gestation in rats infused with ADM2 antagonist during implantation and decidualization phase. Taken together, this study suggests a potential involvement of ADM2 in the rat ovary in regulating synthesis of estradiol to support ovulation and facilitate efficient implantation and placental development for a successful pregnancy.

Intermedin attenuates LPS-induced inflammation in the rat testis

First reported as a vasoactive peptide in the cardiovascular system, intermedin (IMD), also known as adrenomedullin 2 (ADM2), is a hormone with multiple potent roles, including its antioxidant action on the pulmonary, central nervous, cardiovascular and renal systems. Though IMD may play certain roles in trophoblast cell invasion, early embryonic development and cumulus cell-oocyte interaction, the role of IMD in the male reproductive system has yet to be investigated. This paper reports our findings on the gene expression of IMD, its receptor components and its protein localization in the testes. In a rat model, bacterial lippolysaccharide (LPS) induced atypical orchitis, and LPS treatment upregulated the expression of IMD and one of its receptor component proteins, i.e. receptor activity modifying protein 2 (RAMP2). IMD decreased both plasma and testicular levels of reactive oxygen species (ROS) production, attenuated the increase in the gene expression of the proinflammatory cytokines tumor necrosis factor alpha (TNFα), interleukin 6 (IL6) and interleukin 1 beta (IL1β), rescued spermatogenesis, and prevented the decrease in plasma testosterone levels caused by LPS. The restorative effect of IMD on steroidogenesis was also observed in hydrogen peroxide-treated rat primary Leydig cells culture. Our results indicate IMD plays an important protective role in spermatogenesis and steroidogenesis, suggesting therapeutic potential for IMD in pathological conditions such as orchitis.

Intermedin in rat uterus: changes in gene expression and peptide levels across the estrous cycle and its effects on uterine contraction

BACKGROUND

The present study demonstrates the expression of intermedin (IMD) and its receptor components in the uterus of the female rat during the estrous cycle and its effect on uterine contraction.

METHODS

The gene expression level of intermedin and its receptor components and the peptide level of intermedin were studied by real-time RT-PCR and enzyme immunoassay (EIA) respectively. The separation of precursor and mature IMD was studied by gel filtration chromatography and EIA. The localization of IMD in the uterus was investigated by immunohistochemistry. The effect of IMD on in vitro uterine contraction was studied by organ bath technique.

RESULTS

Uterine mRNAs of Imd and its receptor components and IMD levels displayed cyclic changes across the estrous cycle. Imd mRNA level was the highest at proestrus while the IMD level was the highest at diestrus. IMD was found in the luminal and glandular epithelia and IMD treatment significantly reduced the amplitude and frequency of uterine contraction but not the basal tone. Both calcitonin gene-related peptide (CGRP) receptor antagonist hCGRP8-37 and adrenomedullin (ADM) receptor antagonist hADM22-52 partially abolished the inhibitory effect of IMD on uterine contraction while the specific IMD receptor antagonist hIMD17-47 completely blocked the actions. The enzyme inhibitors of NO (L-NAME) and PI3K (Wortmannin) pathways diminished the IMD effects on uterine contraction while the cAMP/PKA blocker, KT5720, had no effect, indicating an involvement of NO and PI3K/Akt but not PKA.

CONCLUSIONS

IMD and the gene expression of its receptor components are differentially regulated in the uterus during the estrous cycle and IMD inhibits uterine contraction by decreasing the amplitude and frequency.

Regulation and 3 dimensional culture of tertiary follicle growth

It has been revealed that multiple cohorts of tertiary follicles develop during some animal estrous cycle and the human menstrual cycle. To reach developmental competence, oocytes need the support of somatic cells. During embryogenesis, the primordial germ cells appear, travel to the gonadal rudiments, and form follicles. The female germ cells develop within the somatic cells of the ovary, granulosa cells, and theca cells. How the oocyte and follicle cells support each other has been seriously studied. The latest technologies in genes and proteins and genetic engineering have allowed us to collect a great deal of information about folliculogenesis. For example, a few web pages (http://www.ncbi.nlm.nih.gov; http://mrg.genetics.washington.edu) provide access to databases of genomes, sequences of transcriptomes, and various tools for analyzing and discovering genes important in ovarian development. Formation of the antrum (tertiary follicle) is the final phase of folliculogenesis and the transition from intraovarian to extraovian regulation. This final step coordinates with the hypothalamic-pituitary-ovarian axis. On the other hand, currently, follicle physiology is under intense investigation, as little is known about how to overcome women's ovarian problems or how to develop competent oocytes from in vitro follicle culture or transplantation. In this review, some of the known roles of hormones and some of the genes involved in tertiary follicle growth and the general characteristics of tertiary follicles are summarized. In addition, in vitro culture of tertiary follicles is also discussed as a study model and an assisted reproductive technology model.