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Pregnancy |
Department of Animal Science, Oklahoma Agriculture Experiment Station,3
Department of Physiological Sciences,4
Department of Veterinary Pathobiology,5 College of Veterinary Medicine, Oklahoma State University, Stillwater, Oklahoma 74078
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ABSTRACT |
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 TOP ABSTRACT INTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONREFERENCES |
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conceptus, cytokines, early development, implantation, pregnancy
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INTRODUCTION |
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TOPABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONREFERENCES |
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Although the biological mechanisms involved with the initiation of trophoblastic remodeling are largely unknown, a few genes proposed to be involved with the rapid transformation of porcine conceptuses have been investigated. Gene expression for retinoic acid receptors (RAR) 
, ß, and 
as well as retinal binding proteins (RBP) has been evaluated during porcine conceptus development and trophoblastic elongation [5]. Results from a semiquantitative polymerase chain reaction (PCR) evaluation of gene expression indicated RAR and RBP increase during transition to the filamentous morphology. Porcine conceptus expression of growth factors such as transforming growth factor-, epidermal growth factor, and interleukin 6 have been reported [6–9]. Pregnancy-specific endometrial expression of leukemia inhibitory factor (LIF) is initiated during the period of conceptus elongation and could affect conceptus development because peri-implantation porcine conceptuses express LIF-receptor ß [8, 9]. Conceptus aromatase gene expression also increased during trophoblastic elongation [10], possibly having an autocrine effect on development through the increase in conceptus estrogen receptor ß expression [11]. Conceptus elongation is associated with increased prostaglandin synthesis and release into the uterine lumen [12]. Increase in prostaglandin release is consistent with the detection of enhanced cyclooxygenase-2 (COX-2) gene expression in filamentous conceptuses following rapid trophoblastic elongation [13].
Recently, interleukin-1ß (IL-1ß), a proinflammatory cytokine, was identified through utilization of suppression subtractive hybridization (SSH) as a gene differentially expressed during the process of rapid trophoblastic elongation [14]. It is possible that IL-1ß serves an important role in trophoblastic elongation and initiation of placental-uterine interfacing needed for the establishment of pregnancy. Previously, Tou et al. [15] reported that conceptus IL-1ß gene expression was high during porcine peri-implantation development on Days 10–12 of pregnancy. Peri-implantation expression of IL-1ß has also been documented to increase prior to initiation of blastocyst implantation in the mouse [16, 17] and has been suggested as the initiator of conceptus-uterine cross talk during pregnancy in the human [18]. Many of the endometrial responses evoked by porcine conceptuses during trophoblastic elongation and subsequent adhesion to the uterine apical surface resemble the IL-1 mediated acute-phase responses induced during inflammation of tissue [19].
The present study was undertaken to evaluate changes in gene expression of IL-1 family members to better understand the role of IL-1ß in embryonic development and establishment of pregnancy in pigs. Gene expression for IL-1ß, IL-1 receptor type 1 (IL-1RT1), IL-1 receptor accessory protein (IL-1RAP), and IL-1 receptor antagonist (IL-1Rant) was analyzed in peri- and postimplantation conceptuses as well as from the endometrium of cyclic and pregnant gilts. Uterine luminal content of IL-1ß was also quantitated during the estrous cycle and early pregnancy. The study was designed to specifically target uterine lumen IL-1ß fluctuation occurring during conceptus transition from spherical to filamentous morphology.
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MATERIALS AND METHODS |
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TOPABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONREFERENCES |
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Research was conducted in accordance with and approved by the Oklahoma State Institutional Animal Care and Use Committee. Cyclic, large white gilts of similar age (8–10 mo) and weight (100–130 kg) were checked for estrus behavior twice daily in the presence of an intact boar. Onset of estrus was designated Day 0 of the estrous cycle. Gilts assigned to be bred were naturally mated with fertile boars at the onset of their second estrus (Day 0 of estrous cycle) and again 24 h later.
Collection of Endometrial Tissue and Conceptuses
Cyclic and pregnant gilts (4 animals/status per day) were hysterectomized through midventral laparotomy as previously described by Gries et al. [20]. Cyclic gilts were hysterectomized on Days 0, 5, 10, 12, 15, and 18 of the estrous cycle while pregnant gilts were hysterectomized on Days 10, 12, 15, and 18 of gestation. Immediately following removal, each uterine horn was flushed with 20 ml of a physiological saline and conceptuses were removed from pregnant gilts. Conceptus morphology was recorded and pools of conceptuses of identical morphologies (spherical, ovoid, tubular, and filamentous) were transferred to cryogenic vials, snap frozen in liquid nitrogen, and transferred to -80°C for long-term storage. Uterine flushings were transferred to a 50-ml conical tube and centrifuged at 1000 rpm for 1 min to remove cell debris. Uterine flushings were stored at -80°C until utilized in an IL-1ß ELISA protein assay. Following conceptus removal, one uterine horn was cut along its antimesometrial border, and endometrium (5–10 g) was removed with sterile scissors. Endometrium was snap frozen in liquid nitrogen and stored at -80°C until analyzed.
Collection of Elongating Porcine Conceptuses
Because the 9- to 10-mm spherical to filamentous transition occurs within a short period of time (2–3 h), collection of tubular conceptuses required utilization of a unilateral hysterectomy procedure previously described by Geisert et al. [1]. For that reason, 15 additional pregnant gilts were utilized to collect conceptuses during the transitional period between Days 11 and 12 of gestation. Conceptuses flushed from the uteri were separated based on morphological development stage (i.e., spherical, ovoid, tubular, filamentous). Conceptuses and uterine flushings were collected and stored at -80°C as described above.
RNA Isolation
Total RNA was extracted from conceptus pools following the extraction method previously described by our laboratory [14]. Conceptuses were denatured for 15 min on ice using 500 µl of denaturing solution (4 M guanidinium thiocyanate, 25 mM sodium citrate, pH 7.0, 0.5% sarcosyl, 0.1 M 2-ß-mercaptoethanol), 500 µl phenol, 70 µl of 2 M sodium acetate (pH 4.0), and 140 µl chloroform/iso-amyl-alcohol (49:1 fresh dilution). The aqueous phase was recovered following centrifugation at 14 000 rpm for 20 min at 4°C and added to a tube containing 500 µl of chloroform/iso-amyl-alcohol (49:1), and centrifuged at 10 000 rpm for 10 min at 4°C. The aqueous phase was recovered, placed in a sterile tube, and 7 µl of Rnaid binding matrix (BIO 101, LaJolla, CA) was added, vortexed briefly, and rotated for 25 min at 22–25°C. Following rotation, the suspension was centrifuged at 10 000 rpm for 2 min and the aqueous phase was discarded. The remaining pellet containing the glass beads bound to total RNA was washed three times using 250 µl of 50% RNA wash (BIO 101) and 50% ethanol solution followed by centrifugation at 10 000 rpm for 2 min at 22–25°C. The pellet was dried at 22–25°C for 10 min and resuspended in 50 µl of nuclease-free H2O. The resuspended solution was heated at 56°C for 5 min and centrifuged at 10 000 rpm for 2 min. Approximately 40 µl of the aqueous phase containing the purified total RNA was transferred to a sterile tube and stored at -80°C. Endometrium tissue total RNA was extracted using the TRIzol reagent (Invitrogen, Carlsbad, CA) according to manufacturer's recommendations as previously described [21]. Approximately 500 mg of endometrium was homogenized in 5 ml TRIzol reagent using a Virtishear homogenizer (Virtis Company Inc., Gardiner, NY). RNA pellets were rehydrated in nuclease-free H2O and stored at -80°C. RNA content was estimated spectrophotometrically and purity determined by the 260:280 ratio.
Quantitative 1-Step RT-PCR
Quantitative analysis of IL-1ß, IL-1RT1, IL-1RAP, and IL-1Rant mRNA were assayed using quantitative real-time reverse transcription-polymerase chain reaction (RT-PCR) and a fluorescent reporter as previously described [22]. Endometrial tissue was assayed in addition to pools (2–7) of conceptuses at the four morphologically distinct stages during rapid trophoblastic elongation, i.e., spherical (n = 8), ovoid (n = 2), tubular (n = 5), and filamentous (n = 6), and during late peri-implantation development, i.e., Days 15 (n = 2) and 18 (n = 5). The PCR amplification was conducted using the ABI PRISM 7700 Sequence Detection System (PE Applied Biosystems, Foster City, CA). The transcripts were evaluated using dual-labeled probes designed to have a 5' reporter dye (6-FAM) and a 3' quenching dye (TAMRA). One hundred nanograms of total RNA were assayed for each sample in duplicate. Thermal cycling conditions were 48°C for 30 min and 95°C for 10 min, followed by 40 repetitive cycles of 95°C for 15 sec and 60°C for 1 min. The 18S ribosomal RNA was assayed as a normalization control to correct for loading discrepancies for all samples assayed. GenBank accession numbers representing full-length cDNA sequences or estimated sequence tags used to generate primer and probe sequences for the amplification of IL-1ß, IL-1RT1, IL-1RAP, and IL-1Rant are presented in Table 1. Primer and probe sequences generated for IL-1ß using the available porcine GenBank sequence (accession # M86725) efficiently amplified endometrial IL-1ß. However, the amplification of conceptus IL-1ß gene expression with the same primers and probe was not exponential. The IL-1ß cDNA sequence previously isolated in our laboratory (GenBank accession # AY291592) has only 90% homology to the known porcine IL-1ß sequence (GenBank accession # M86725). The region in which the primers and probe were constructed (exon number 5) to amplify IL-1ß was not totally homologous (81%) between the porcine lung IL-1ß sequence in GenBank (# M86725) and conceptus sequence isolated using SSH (GenBank accession # AY291592) [14]. A second set of primers and probe were designed using the isolated IL-1ß cDNA sequence from conceptuses (Table 1).
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Template amplification was quantified by determining the threshold cycle (CT) based on the fluorescence detected within the geometric region of the semilog plot. In the geometric region, one cycle is equivalent to the doubling of the PCR target template. Using the comparative CT method [22], relative quantification and fold gene expression differences were determined for different conceptus stages (Table 2) and endometrial status during days of the estrous cycle and early pregnancy (Tables 3 and 4). The 
CT value was determined by subtracting the target CT of each sample from its respective ribosomal 18S CT value. Calculation of CT involves using the highest sample CT value as an arbitrary constant to subtract from all other CT sample values. Fold changes in gene expression of the target gene are equivalent to 2-Ct.
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Enzyme-Linked Immunosorbent Assay
The IL-1ß protein content in uterine luminal flushings of Day 12 and 15 cyclic gilts and pregnant gilts with spherical, ovoid, tubular, filamentous, and in Day 15 and 18 conceptuses was quantified using a commercially available ELISA (R&D Systems, Minneapolis, MN). The assay employs the quantitative sandwich enzyme immunoassay technique using a monoclonal antibody specific to porcine IL-1ß precoated onto a microplate. Due to concentrations that exceeded the standard curve, a number of samples were diluted with calibrator diluent RD6-33 (R&D Systems) to place the samples within the sensitivity of the assay (10–2500 pg/ml). All samples, standards, and controls were assayed in duplicate. The assay was conducted according to the manufacturer's recommendations (R&D Systems). IL-1ß concentrations were calculated based on the generated standard curve. The intraassay coefficient of variation of the IL-1ß ELISA was 4.8%.
Statistical Analysis
Quantitative RT-PCR CT values were analyzed using PROC MIXED of the Statistical Analysis System [23]. Analysis of conceptus gene expression tested for the fixed effect of morphology. The analysis of endometrial gene expression tested for the effect of status, day, and status x day interaction. The effect of status, day, and status x day interaction was evaluated for IL-1ß protein in uterine flushings from Day 12 and 15 pregnant and cyclic gilts. The fixed effect of conceptus morphology was tested for IL-1ß protein in uterine flushings from pregnant uteri during trophoblastic elongation (Days 11–12), and for Days 15 and 18. Significance (P < 0.05) was determined by probability differences of least squares means. A Satterthwaite approximation was used for means with heterogeneous variance to calculate the effective degrees of freedom for the error term [24]. Results are presented as arithmetic means ± SEM.
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RESULTS |
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TOPABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONREFERENCES |
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Interleukin-1ß A significant difference (P < 0.0001) in IL-1ß gene expression between morphological variants during porcine trophoblast development was detected using quantitative RT-PCR (Table 2). Selectively comparing fold differences in IL-1ß gene expression only during the period of trophoblastic elongation indicates an approximate 2-fold increase in IL-1ß gene expression during conceptus transition from spherical to tubular conceptuses, which increased to 6-fold in filamentous conceptuses (Fig. 1). Comparing all morphologies evaluated, greatest IL-1ß gene expression was detected in Day 12 filamentous conceptuses, which was over 2200- and 1200-fold greater compared with conceptuses collected on Days 15 and 18 of pregnancy, respectively (Fig. 1). The IL-1ß gene expression was extremely low in Day 15 and 18 conceptuses as spherical conceptuses expressed over 300-fold greater IL-1ß compared with postelongation conceptuses (Fig. 1).
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No significant status or day x status interaction was detected in endometrial IL-1ß gene expression (Table 3). However, there was a tendency for a day effect (P < 0.06) as gene expression for IL-1ß was greater during estrus (Day 0) and early diestrus (Day 5) compared with the later days of the estrous cycle and early pregnancy (Fig. 2).
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Interleukin-1 receptor type I Conceptus IL-1 RT1 gene expression was affected (P < 0.003) by morphological stage of development (Table 2). IL-1RT1 expression was lowest in tubular conceptuses compared with all other morphologies (Table 2). Similar to IL-1ß gene expression, filamentous conceptuses expressed greater IL-1RT1 mRNA when compared with spherical and tubular conceptuses (Table 2). IL-1RT1 mRNA expression was approximately 6-fold greater in Day 12 filamentous conceptuses compared with spherical conceptuses and approximately 17-fold greater than tubular conceptuses (Fig. 3).
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A day x status interaction (P < 0.0001) was detected in endometrial IL-1RT1 gene expression (Table 4). Endometrium from Day 12 of gestation contained greater (P < 0.04) mRNA levels of IL-1RT1 compared with all other days of the estrous cycle and pregnancy (Table 4). Endometrial IL-1RT1 gene expression was enhanced 2- to 4-fold on Day 12 of pregnancy compared with all days of estrous cycle and pregnancy (Fig. 4).
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Interleukin-1 receptor accessory protein Conceptus IL-1RAP gene expression was affected (P < 0.0001) by morphological stage of development (Table 2). The IL-1RAP gene expression increased and was maintained following trophoblastic elongation (Fig. 3). The greatest IL-1RAP mRNA expression occurred in Day 15 conceptuses compared with all other morphologies evaluated, while tubular conceptuses contained the lowest IL-1RAP mRNA (Table 2). Compared with tubular conceptuses, IL-1RAP expression was approximately 5-, 23-, and 7-fold greater in filamentous (Day 12) and Day 15 and 18 conceptuses, respectively (Fig. 3).
Evaluation of endometrial IL-1RAP gene expression (Table 4) detected a day x status interaction (P < 0.03). The highest IL-1RAP mRNA expression was detected in endometrium collected on Day 12 of pregnancy (Table 4). The IL-1RAP gene expression was enhanced approximately 8-fold compared with Days 10–18 of the estrous cycle and 3-fold compared with Days 15 and 18 of gestation (Fig. 5).
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Interleukin-1 receptor antagonist Gene expression for IL-1Rant was not affected (P < 0.74) by morphological stage of conceptus development (Table 2).
A day x status interaction (P < 0.03) was detected for endometrial IL-1Rant gene expression (Table 3). Endometrial IL-1Rant gene expression was greatest on Day 0 of the estrous cycle (Table 3). IL-1Rant endometrial gene expression was high during estrus and early diestrus (Day 5), rapidly declining during diestrus and early pregnancy (Fig. 6). Differences in gene expression were approximately 50- to 90-fold greater on Days 0 and 5 compared with endometrium during the time of peak conceptus IL-1ß gene expression occurring on Day 12 of gestation (Fig. 6).
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IL-1ß Protein
Analysis of IL-1ß protein in uterine flushings of pregnant and cyclic gilts from Days 12 and 15 of gestation or the estrous cycle indicated a status effect (P < 0.003). The uterine concentration of IL-1ß was below the detectable range of the ELISA (10 pg/ml) in flushings from all cyclic gilts while the concentration of IL-1ß in uterine flushings averaged 184 ± 50.3 and 112 ± 31.4 ng/ml on Days 12 and 15 of pregnancy, respectively. When data were analyzed for pregnant gilts only, there was an effect (P < 0.003) of conceptus morphology in the uterine horn on the concentration of IL-1ß protein in the uterine flushings. Concentration of IL-1ß in the uterine flushings from pregnant gilts increased during the transition from spherical (2.9 ± 1.0 ng/ml) to tubular (65.4 ± 10.7 ng/ml) morphology and peaked during the presence of Day 12 filamentous conceptuses (Fig. 7). The IL-1ß protein content in the uterine lumen declined slightly by Day 15 and returned to concentrations similar to uteri containing spherical conceptuses on Day 18 (5.9 ± 1.5 ng/ml) of gestation.
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DISCUSSION |
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TOPABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONREFERENCES |
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IL-1ß is a proinflammatory cytokine associated with implantation in the mouse [16, 17] and has been suggested as the initiator of cross talk between human embryos and the endometrium during initiation of implantation [18]. Deletion of IL-1RT1 in knockout mice results in only a slightly reduced litter size [27]. However, repeated injections of IL-1Rant into pregnant mice prior to implantation caused implantation failure [28]. Regardless of the receptor pathway, these studies indicate the importance of IL-1ß signaling during implantation in the mouse. Detection of porcine conceptus IL-1ß gene expression led us to investigate expression patterns of IL-1ß, IL-1RT1, IL-1RAP, and IL-1Rant in conceptuses and uterine endometrium during peri-implantation development and the establishment of pregnancy in the pig.
The present study clearly demonstrates the presence of IL-1ß in the uterine lumen during the time of conceptus elongation and maternal recognition of pregnancy on Day 12 of gestation. Uterine luminal content of IL-1ß increased during the initiation of rapid trophoblastic elongation. Absence of IL-1ß protein in the uterine lumen on Days 12 and 15 of the estrous cycle with the increase in conceptus IL-1ß gene expression detected during trophoblastic elongation suggests the IL-1ß in the uterine lumen originates from peri-implantation conceptuses. Following the initial sharp increase in IL-1ß on Day 12, conceptus gene expression and release of IL-1ß is greatly reduced by Days 15 and 18 of gestation. IL-1ß gene expression was more than 2000-fold less in Day 15 conceptuses compared with Day 12 filamentous conceptuses. Similarly, IL-1ß protein availability in the uterine lumen is declining on Day 15 and returns to pre-elongation concentrations by Day 18 of gestation. This transient pattern of conceptus IL-1ß gene expression and protein secretion is temporally and spatially associated with IL-1RT1 and IL-1RAP gene expression in elongated conceptuses (Days 12–15) and in endometrium from pregnant gilts on Day 12 of gestation. Conceptus expression for IL-1RT1 and IL-1RAP is greater in filamentous conceptuses compared with earlier morphologies and tends to decline in Day 18 conceptuses.
IL-1ß ligand binding to both IL-1RT1 and IL-1RAP is needed to elicit a biological response [29], although as indicated above, IL-1ß may function through multiple receptors. The upregulation of IL-1RT1 gene expression in both the endometrium and conceptuses may be in part due to the actions of IL-1ß itself, which is known to upregulate the expression of its own receptor, IL-1RT1, in human endometrial stromal and glandular cells [30]. Endometrial IL-1RT1 and IL-1RAP gene expression decreased following conceptus trophoblastic elongation and initial apposition to the uterine apical surface on Day 12 of gestation, whereas conceptus IL-1RT1 and IL-1RAP gene expression continued to be elevated following conceptus expansion. Endometrial IL-1RT1 gene expression during the time of blastocyst attachment to the uterine surface is similarly expressed with respect to implantation in the mouse [31] and human [32]. In contrast with the pig, IL-1RAP gene expression in human endometrium is constitutively expressed throughout the menstrual cycle without significant variation, although its presence is more intense in glandular and lumenal epithelium [33].
Based on temporal IL-1RT1, IL-1RAP, and IL-1Rant gene expression, conceptus IL-1ß gene expression and presence in the uterine lumen likely induces biological actions in both the porcine conceptus and endometrium. Although we have demonstrated conceptus and endometrial gene expression for IL-1RT1, IL-1RAP, and IL-1Rant, further studies are needed to investigate protein changes for the receptors and receptor antagonists associated with the increased release of conceptus IL-1ß.
IL-1ß is a potent stimulator of aromatase activity and subsequent estrogen (E2) synthesis in human cytotrophoblasts [34] and also stimulates progesterone production in JEG-3 choriocarcinoma cells [35]. Aromatase gene expression is increased in Day 12 filamentous pig conceptuses compared with earlier morphologies [10]. Estrogen production in porcine conceptuses sharply increases during elongation on Day 12, declines rapidly on Day 13, and then initiates a second more sustained increase on Days 16–25 of gestation [19]. Conceptus IL-1ß gene expression and protein secretion is temporally associated with initiation of conceptus E2 production during the process of rapid trophoblastic elongation, suggesting IL-1ß may be involved with the E2 increase in elongating conceptuses. However, conceptus IL-1RT1 and IL-1 RAP gene expression and continued IL-1ß presence in the uterine lumen through Day 15 suggests IL-1ß could have effects on conceptus and uterine function after trophoblastic elongation. Although the initial conceptus enhancement of E2 synthesis may involve IL-1ß, our data suggest the second sustained increase in porcine conceptus E2 release initiated on Day 16 is mediated by an alternative mechanism because IL-1ß gene expression is almost absent in Day 15 and 18 conceptuses.
IL-1ß, an inducer of phospholipase A2 [36], may also regulate the release of arachidonic acid from the phospholipid bilayer, allowing membrane fluidity necessary for remodeling of the trophectoderm during elongation and its conversion to prostaglandins needed for placental attachment during the establishment of pregnancy [19, 37]. IL-1ß induces cyclo-oxygenase-2 (COX-2) gene expression in human endometrial stromal cells [38] and amnion-derived WISH cells [39]. Filamentous (Day 12) porcine conceptuses express elevated levels of COX-2 mRNA [13] that are temporally associated with the IL-1ß gene expression we report. While conceptus production of prostaglandins may not be necessary for inducing trophoblastic elongation [12], prostaglandins have been demonstrated to be essential for placental attachment and survival following elongation [40].
During placental attachment in the pig, the conceptus invokes an acute-phase inflammatory response [19]. At this time, the formation of a conceptus-uterine extracellular matrix is essential. Tumor necrosis factor (TNF)-stimulated gene (TSG)-6 gene expression is induced by TNF and IL-1ß [41] as well as prostaglandin E2 (PGE) [42]. TSG-6, which is strongly anti-inflammatory [43], is thought to be involved in cumulus-oocyte matrix formation in mice because of its ability to bind to both hyaluronic acid and the heavy chain of inter--trypsin inhibitor (II) stabilizing the covalent bond between the two [44]. II has been reported in the porcine endometrium and hypothesized to assist in attachment of the conceptus to the uterine surface by stabilizing the uterine epithelial surface glycocalyx [19]. It is possible that conceptus IL-1ß production may initially stimulate TSG-6 production during conceptus elongation and induce COX-2 expression for continued stimulation of TSG-6 through placental PGE release. Conceptus and endometrial expression of TSG-6 during establishment of pregnancy is currently under investigation.
The significance of the inflammatory response induced via IL-1ß lies in the effects IL-1ß may have on the regulation of the maternal T helper cell (TH) population at the fetal-maternal interface allowing a permissive response to conceptus antigens. In mice, shifting from predominately a TH1 population, which is not compatible with pregnancy [45], to a TH2 population, is generally associated with successful pregnancies [46]. TH2 proliferation in mice requires IL-1 expression by antigen-presenting cells [47] and recurrent pregnancy loss in women has been linked to TH1-type immunity to trophoblastic antigens due to polymorphisms in the IL-1ß promoter region of the mother [48], suggesting that IL-1ß may be involved in regulating a maternal immune response that is permissive to conceptus antigens in the pig.
Using quantitative real-time RT-PCR and a commercial ELISA assay, we have clearly demonstrated changes in porcine conceptus IL-1ß gene expression, synthesis, and release during rapid trophoblastic elongation and its potential signaling pathways in both the uterine endometrium and conceptus. Based on current literature and the dynamic conceptus IL-1ß gene expression and synthesis temporally and spatially to IL-1RT1 and IL-1RAP gene expression in the uterine endometrium, we suggest IL-1ß is an imperative maternal signaling component required for the establishment of a successful pregnancy in the pig.
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ACKNOWLEDGMENTS |
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FOOTNOTES |
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2 Correspondence: Rodney D. Geisert, Department of Animal Science, Animal Science Building, Rm 114, Oklahoma State University, Stillwater, OK 74078-6051. FAX: 405 744 7390; geisert{at}okstate.edu
Received: 27 January 2003.
First decision: 2 March 2003.
Accepted: 28 May 2003.
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REFERENCES |
|---|
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TOPABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONREFERENCES |
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, EGF and EGF receptor during early pig development. Development 1992 116:663-669[Abstract], interleukin-1ß, and interleukin-1 receptor type I mRNA during preimplantation mouse development. J Reprod Immunol 1996 32:27-35[CrossRef][Medline] and prostaglandin E2. Am J Pathol 2002 160:1495-1502-inhibitor and exerts a strong anti-inflammatory effect in vivo. J Immunol 1996 156:1609-1615[Abstract]This article has been cited by other articles:
|
|
 |
|
  J. R. Miles, B. A. Freking, L. A. Blomberg, J. L. Vallet, and K. A. Zuelke Conceptus development during blastocyst elongation in lines of pigs selected for increased uterine capacity or ovulation rate J Anim Sci, September 1, 2008; 86(9): 2126 - 2134. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 C. Herrmann-Lavoie, C. V. Rao, and A. Akoum Chorionic Gonadotropin Down-Regulates the Expression of the Decoy Inhibitory Interleukin 1 Receptor Type II in Human Endometrial Epithelial Cells Endocrinology, November 1, 2007; 148(11): 5377 - 5384. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. W. Ross, M. D. Ashworth, F. J. White, G. A. Johnson, P. J. Ayoubi, U. DeSilva, K. M. Whitworth, R. S. Prather, and R. D. Geisert Premature Estrogen Exposure Alters Endometrial Gene Expression to Disrupt Pregnancy in the Pig Endocrinology, October 1, 2007; 148(10): 4761 - 4773. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. M. Joyce, R. C. Burghardt, R. D. Geisert, J. R. Burghardt, R. N. Hooper, J. W. Ross, M. D. Ashworth, and G. A. Johnson Pig Conceptuses Secrete Estrogen and Interferons to Differentially Regulate Uterine STAT1 in a Temporal and Cell Type-Specific Manner Endocrinology, September 1, 2007; 148(9): 4420 - 4431. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 M. M. Joyce, J. R. Burghardt, R. C. Burghardt, R. N. Hooper, L. A. Jaeger, T. E. Spencer, F. W. Bazer, and G. A. Johnson Pig Conceptuses Increase Uterine Interferon-Regulatory Factor 1 (IRF1), but Restrict Expression to Stroma Through Estrogen-Induced IRF2 in Luminal Epithelium Biol Reprod, August 1, 2007; 77(2): 292 - 302. [Abstract] [Full Text] [PDF]
|
|
|
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H. Ka, S. Al-Ramadan, D. W. Erikson, G. A. Johnson, R. C. Burghardt, T. E. Spencer, L. A. Jaeger, and F. W. Bazer Regulation of Expression of Fibroblast Growth Factor 7 in the Pig Uterus by Progesterone and Estradiol Biol Reprod, July 1, 2007; 77(1): 172 - 180. [Abstract] [Full Text] [PDF]
|
|
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|
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M. D. Ashworth, J. W. Ross, J. Hu, F. J. White, D. R. Stein, U. DeSilva, G. A. Johnson, T. E. Spencer, and R. D. Geisert Expression of Porcine Endometrial Prostaglandin Synthase During the Estrous Cycle and Early Pregnancy, and Following Endocrine Disruption of Pregnancy Biol Reprod, June 1, 2006; 74(6): 1007 - 1015. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 T. A. Sato and M. D. Mitchell Molecular inhibition of histone deacetylation results in major enhancement of the production of IL-1beta in response to LPS Am J Physiol Endocrinol Metab, March 1, 2006; 290(3): E490 - E493. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 C. Tayade, G. P. Black, Y. Fang, and B. A. Croy Differential Gene Expression in Endometrium, Endometrial Lymphocytes, and Trophoblasts during Successful and Abortive Embryo Implantation J. Immunol., January 1, 2006; 176(1): 148 - 156. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 M D Ashworth, J W Ross, D R Stein, D T Allen, L J Spicer, and R D Geisert Endocrine disruption of uterine insulin-like growth factor expression in the pregnant gilt Reproduction, October 1, 2005; 130(4): 545 - 551. [Abstract] [Full Text] [PDF]
|
|
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|
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L. E. Jensen and A. S. Whitehead The 3' Untranslated Region of the Membrane-Bound IL-1R Accessory Protein mRNA Confers Tissue-Specific Destabilization J. Immunol., November 15, 2004; 173(10): 6248 - 6258. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 M. Nishida, K. Nasu, J. Fukuda, Y. Kawano, H. Narahara, and I. Miyakawa Down-Regulation of Interleukin-1 Receptor Type 1 Expression Causes the Dysregulated Expression of CXC Chemokines in Endometriotic Stromal Cells: A Possible Mechanism for the Altered Immunological Functions in Endometriosis J. Clin. Endocrinol. Metab., October 1, 2004; 89(10): 5094 - 5100. [Abstract] [Full Text] [PDF]
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