Expression and regulation of chemokine genes in the mouse uterus during pregnancy

Going Full TeRM: The Seminal Role of Tissue-Resident Macrophages in Organ Remodeling during Pregnancy and Lactation

During pregnancy and lactation, the uterus and mammary glands undergo remarkable structural changes to perform their critical reproductive functions before reverting to their original dormant state upon childbirth and weaning, respectively. Underlying this incredible plasticity are complex remodeling processes that rely on coordinated decisions at both the cellular and tissue-subunit levels. With their exceptional versatility, tissue-resident macrophages play a variety of supporting roles in these organs during each stage of development, ranging from maintaining immune homeostasis to facilitating tissue remodeling, although much remains to be discovered about the identity and regulation of individual macrophage subsets. In this study, we review the increasingly appreciated contributions of these immune cells to the reproductive process and speculate on future lines of inquiry. Deepening our understanding of their interactions with the parenchymal or stromal populations in their respective niches may reveal new strategies to ameliorate complications in pregnancy and breastfeeding, thereby improving maternal health and well-being.

Immune Regulation of Seminal Plasma on the Endometrial Microenvironment: Physiological and Pathological Conditions

Seminal plasma (SP) accounts for more than 90% of semen volume. It induces inflammation, regulates immune tolerance, and facilitates embryonic development and implantation in the female reproductive tract. In the physiological state, SP promotes endometrial decidualization and causes changes in immune cells such as macrophages, natural killer cells, regulatory T cells, and dendritic cells. This leads to the secretion of cytokines and chemokines and also results in the alteration of miRNA profiles and the expression of genes related to endometrial tolerance and angiogenesis. Together, these changes modulate the endometrial immune microenvironment and contribute to implantation and pregnancy. However, in pathological situations, abnormal alterations in SP due to advanced age or poor diet in men can interfere with a woman's immune adaptation to pregnancy, negatively affecting embryo implantation and even the health of the offspring. Uterine pathologies such as endometriosis and endometritis can cause the endometrium to respond negatively to SP, which can further contribute to pathological progress and interfere with conception. The research on the mechanism of SP in the endometrium is conducive to the development of new targets for intervention to improve reproductive outcomes and may also provide new ideas for semen-assisted treatment of clinical infertility.

The effects of protein level on cytokines and chemokines in the uterine environment of beef heifers during development

The development of replacement heifers is crucial for breeding success and herd efficiency. Nutritional management can affect not only reproductive development but also the inflammatory status of the uterine environment, which may impact reproductive functions such as pregnancy establishment and development. The study herein evaluated the concentration of cytokines and chemokines in the uterus of heifers supplemented with different levels of protein. Angus heifers (n = 60) were blocked by body weight (BW) and randomly assigned to 1 of 3 treatments based on protein supplementation level: control of 10% crude protein (CON), 20% crude protein (P20), or 40% crude protein (P40). BW, body condition score, and blood samples were taken every 2 wk for 140 d to monitor development. Uterine flushes were performed monthly and concentrations of cytokines (IL-1α, IL-1β, TNF-α, IFN-γ, IL-10, VEGF-α, IL-17A, and IL-36RA) and chemokines (IL-8, MCP-1, MIP-1α, and MIP-1β) were quantified via ELISA multiplex. To test if there were mean differences in cytokines between the treatment groups or over time, PROC GLIMMIX (SAS v 9.4) was utilized. Concentrations of all cytokines and chemokines, except IL-1α, changed throughout heifer development (P < 0.05). Heifers in the P40 treatment group displayed reduced concentrations of MCP-1 (P = 0.007) and tended to have decreased concentrations of IFN-γ (P = 0.06). Cytokine IL-36RA tended (P = 0.06) to be affected by protein level, with the lowest concentrations observed in CON heifers. Most cytokines and chemokines increased following the initial month of supplementation (P < 0.05). The increase in concentrations after 1 mo may indicate an adaptive response in the uterus to diet change. Cytokines and chemokines fluctuated due to physiological changes occurring during development. Further research is needed to determine the influence of nutrition on uterine inflammation and long-term impacts on reproductive function.

The Female Response to Seminal Fluid

Seminal fluid is often assumed to have just one function in mammalian reproduction, delivering sperm to fertilize oocytes. But seminal fluid also transmits signaling agents that interact with female reproductive tissues to facilitate conception and .pregnancy. Upon seminal fluid contact, female tissues initiate a controlled inflammatory response that affects several aspects of reproductive function to ultimately maximize the chances of a male producing healthy offspring. This effect is best characterized in mice, where the female response involves several steps. Initially, seminal fluid factors cause leukocytes to infiltrate the female reproductive tract, and to selectively target and eliminate excess sperm. Other signals stimulate ovulation, induce an altered transcriptional program in female tract tissues that modulates embryo developmental programming, and initiate immune adaptations to promote receptivity to implantation and placental development. A key result is expansion of the pool of regulatory T cells that assist implantation by suppressing inflammation, mediating tolerance to male transplantation antigens, and promoting uterine vascular adaptation and placental development. Principal signaling agents in seminal fluid include prostaglandins and transforming growth factor-β. The balance of male signals affects the nature of the female response, providing a mechanism of ‟cryptic female choiceˮ that influences female reproductive investment. Male-female seminal fluid signaling is evident in all mammalian species investigated including human, and effects of seminal fluid in invertebrates indicate evolutionarily conserved mechanisms. Understanding the female response to seminal fluid will shed new light on infertility and pregnancy disorders and is critical to defining how events at conception influence offspring health.

Male Seminal Relaxin Contributes to Induction of the Post-mating Cytokine Response in the Female Mouse Uterus

The hormone relaxin is important in female reproduction for embryo implantation, cardiovascular function, and during labor and lactation. Relaxin is also synthesized in males by organs of the male tract. We hypothesized that relaxin might be one component of seminal plasma responsible for eliciting the female cytokine response induced in the uterus at mating. When recombinant relaxin was injected into the uterus of wild-type (Rln^+/+) mice at estrus, it evoked the production of Cxcl1 mRNA and its secreted protein product CXCL1 in four of eight animals. Mating experiments were then conducted using mice with a null mutation in the relaxin gene (Rln^−/− mice). qRT-PCR analysis of mRNA expression in wild-type females showed diminished uterine expression of several cytokine and chemokine genes in the absence of male relaxin. Similar differences were also noted comparing Rln^−/− and Rln^+/+ females mated to wild-type males. Quantification of uterine luminal fluid cytokine content confirmed that male relaxin provokes the production of CXCL10 and CSF3 in Rln^+/+ females. Differences were also seen comparing Rln^−/− and Rln^+/+ females mated with Rln^−/− males for CXCL1, CSF3, and CCL5, implying that endogenous relaxin in females might prime the uterus to respond appropriately to seminal fluid at coitus. Finally, pan-leukocyte CD45 mRNA was increased in wild-type matings compared to other combinations, implying that male and female relaxin may trigger leukocyte expansion in the uterus. We conclude that male and/or female relaxin may be important in activating the uterine cytokine/chemokine network required to initiate maternal immune adaptation to pregnancy.

TLR4 Signaling Is a Major Mediator of the Female Tract Response to Seminal Fluid in Mice

Seminal fluid interacts with epithelial cells lining the female reproductive tract to induce expression of proinflammatory cytokines and chemokines, initiating immune tolerance mechanisms to facilitate pregnancy. TGFB cytokines are key signaling agents in seminal plasma but do not fully account for the female response to seminal fluid. We hypothesized that additional molecular pathways are utilized in seminal fluid signaling. Affymetrix microarray was employed to compare gene expression in the endometrium of mice 8 h after mating with either intact males or seminal fluid deficient (SVX/VAS) males. Bioinformatics analysis revealed TLR4 signaling as a strongly predicted upstream regulator activated by the differentially expressed genes and implicated TGFB signaling as a second key pathway. Quantitative PCR and microbead data confirmed that seminal fluid induces endometrial synthesis of several TLR4-regulated cytokines and chemokines, including CSF3, CXCL1, CXCL2, IL1A, IL6, LIF, and TNF. In primary uterine epithelial cells, CSF3, CXCL1, and CXCL2 were strongly induced by the TLR4 ligand LPS but suppressed by TGFB, while IL1A, TNF, and CSF2 were induced by both ligands. TLR4 was confirmed as essential for the full endometrial cytokine response using mice with a null mutation in Tlr4, where seminal fluid failed to induce endometrial Csf3, Cxcl2, Il6, and Tnf expression. This study provides evidence that TLR4 contributes to seminal fluid modulation of the periconception immune environment. Activation of TLR4 signaling by microbial or endogenous components of seminal fluid is thus implicated as a key element of the female tract response to seminal fluid at the outset of pregnancy in mice.

Epithelial and stromal-specific immune pathway activation in the murine endometrium post-coitum

The endometrium is a dynamic tissue, demonstrating cyclical growth/remodelling in preparation for implantation. In mice, seminal constituents trigger mechanisms to prepare the endometrium, a process dubbed 'seminal priming' that modifies immune system components and mediates endometrial remodelling in preparation for pregnancy. An array of cytokines has been reported to mediate this interaction, although much of the literature relates to in vitro studies on isolated endometrial epithelial cells. This study measured changes in immune-related gene expression in endometrial epithelial and stromal cells in vivo following natural mating. CD1 mice were naturally mated and sacrificed over the first 4 days post-coitum (n=3 each day). Endometrial epithelial and stromal compartments were isolated by laser capture microdissection. Labelled cRNA was generated and hybridised to genome-wide expression microarrays. Pathway analysis identified several immune-related pathways active within epithelial and stromal compartments, in particular relating to cytokine networks, matrix metalloproteinases and prostaglandin synthesis. Cluster analysis demonstrated that the expression of factors involved in immunomodulation/endometrial remodelling differed between the epithelial and stromal compartments in a temporal fashion. This study is the first to examine the disparate responses of the endometrial epithelial and stromal compartments to seminal plasma in vivo in mice, and demonstrates the complexity of the interactions between these two compartments needed to create a permissive environment for implantation.

Differential migration and activation profile of monocytes after trophoblast interaction

Macrophages at the maternal-placental interface coordinate opposite demands under the control of trophoblast cells such as the response against pathogens on one hand, and apoptotic cell clearance and wound healing with the production of suppressor cytokines. Here, we investigated whether trophoblast cells induce maternal monocyte activation towards an alternative activated macrophage profile and whether bacterial or viral stimuli modulate their migratory properties. We used an in vitro model of the maternal-placental interface represented by co-cultures of CD14+ cells isolated from fertile women with first trimester trophoblast cell line (Swan-71 cells) in the presence or absence of pathogen associated molecular pattern (PAMP) stimuli lipopolysaccharide (LPS), peptidoglycan (PGN) or poly [I:C]). Maternal CD14+ cells showed increased CD16 and CD39 expression, both markers associated to an alternative activation profile, with no changes in CD80 expression after trophoblast cell interaction. These changes were accompanied by increased IL-10 and decreased IL-12 production by CD14+ cells. After stimulation with LPS, PGN or poly [I:C], monocytes co-cultured with trophoblast cells had lower production of TNF-α and IL-1β compared with non co-cultured monocytes. Interestingly, monocyte migration towards trophoblast cells was prevented in the presence of LPS or PGN but not after 24h of stimulation with poly [I:C]. LPS or PGN also decreased CCR5, CXCL-8 and CCL5 expression. Finally, trophoblast cells co-cultured with monocytes in the presence of pathological stimuli failed to increase chemokine expression, indicating a bidirectional effect. In conclusion, trophoblast might 'instruct' maternal monocytes to express an alternative activation profile and restrain their early recruitment under pathological threats as one of the first strategies to avoid potential tissue damage at the maternal-placental interface.

Glucose-6-phosphatase-β, implicated in a congenital neutropenia syndrome, is essential for macrophage energy homeostasis and functionality

Glucose-6-phosphatase-β (G6Pase-β or G6PC3) deficiency, also known as severe congenital neutropenia syndrome 4, is characterized not only by neutropenia but also by impaired neutrophil energy homeostasis and functionality. We now show the syndrome is also associated with macrophage dysfunction, with murine G6pc3(-/-) macrophages having impairments in their respiratory burst, chemotaxis, calcium flux, and phagocytic activities. Consistent with a glucose-6-phosphate (G6P) metabolism deficiency, G6pc3(-/-) macrophages also have a lower glucose uptake and lower levels of G6P, lactate, and ATP than wild-type macrophages. Furthermore, the expression of NADPH oxidase subunits and membrane translocation of p47(phox) are down-regulated, and G6pc3(-/-) macrophages exhibit repressed trafficking in vivo both during an inflammatory response and in pregnancy. During pregnancy, the absence of G6Pase-β activity also leads to impaired energy homeostasis in the uterus and reduced fertility of G6pc3(-/-) mothers. Together these results show that immune deficiencies in this congenital neutropenia syndrome extend beyond neutrophil dysfunction.

Keratinocyte Growth Factor Stimulates Macrophage Inflammatory Protein 3α and Keratinocyte-derived Chemokine Secretion by Mouse Uterine Epithelial Cells

PROBLEM

communication between uterine epithelial cells and the underlying stromal fibroblasts is critical for proper endometrial function. Stromal fibroblast-derived growth factors have been shown to regulate epithelial immune functions. The purpose of this study was to determine whether keratinocyte growth factor (KGF) regulates uterine epithelial cell chemokine and antimicrobial secretion.

METHOD OF STUDY

uterine epithelial cells were isolated from Balb/c mice and cultured in either 96-well plates or transwell inserts. Epithelial cells were treated with KGF, epidermal growth factor (EGF), or hepatocyte growth factor (HGF). Macrophage inflammatory protein 3α (MIP3α) and keratinocyte-derived chemokine (KC) levels were measured by ELISA.

RESULTS

keratinocyte growth factor stimulated the secretion of MIP3α and KC. The effects on MIP3α by KGF were specific because EGF and HGF had no effect. In contrast, KGF, EGF, and HGF had similar effects on KC. Furthermore, KGF administered to the apical side of epithelial cells had no effect on MIP3α or KC secretion, indicating that the KGF receptor is located on the basolateral surface of uterine epithelial cells.

CONCLUSION

we demonstrate that KGF plays a role in uterine epithelial cell secretion of MIP3α and KC, key immune mediators involved in the protection of mucosal surfaces in the female reproductive tract.

Contraceptive vaccines targeting factors involved in establishment of pregnancy

Current methods of contraception lack specificity and are accompanied with serious side effects. A more specific method of contraception is needed. Contraceptive vaccines can provide most, if not all, the desired characteristics of an ideal contraceptive. This article reviews several factors involved in the establishment of pregnancy, focusing on those that are essential for successful implantation. Factors that are both essential and pregnancy-specific can provide potential targets for contraception. Using database search, 76 factors (cytokines/chemokines/growth factors/others) were identified that are involved in various steps of the establishment of pregnancy. Among these factors, three, namely chorionic gonadotropin (CG), leukemia inhibitory factor (LIF), and pre-implantation factor (PIF), are found to be unique and exciting molecules. Human CG is a well-known pregnancy-specific protein that has undergone phase I and phase II clinical trials, in women, as a contraceptive vaccine with encouraging results. LIF and PIF are pregnancy-specific and essential for successful implantation. These molecules are intriguing and may provide viable targets for immunocontraception. A multiepitope vaccine combining factors/antigens involved in various steps of the fertilization cascade and pregnancy establishment may provide a highly immunogenic and efficacious modality for contraception in humans.

Seminal fluid regulates accumulation of FOXP3+ regulatory T cells in the preimplantation mouse uterus through expanding the FOXP3+ cell pool and CCL19-mediated recruitment

Regulatory T (Treg) cells facilitate maternal immune tolerance of the semiallogeneic conceptus in early pregnancy, but the origin and regulation of these cells at embryo implantation is unclear. During the preimplantation period, factors in the seminal fluid delivered at coitus cause expansion of a CD4(+)CD25(+) putative Treg cell population in the para-aortic lymph nodes draining the uterus. Using flow cytometry, immunohistochemistry, and real-time quantitative PCR (qPCR) for the signature Treg cell transcription factor FOXP3, we confirmed the identity of the expanded lymph node population as FOXP3(+) Treg cells and showed that this is accompanied by a comparable increase in the uterus of FOXP3(+) Treg cells and expression of Foxp3 mRNA by Day 3.5 postcoitum. Seminal plasma was necessary for uterine Treg cell accumulation, as mating with seminal vesicle-deficient males failed to elicit an increase in uterine Treg cells. Furthermore seminal fluid induced expression of mRNA encoding the Treg chemokine CCL19 (MIP3beta), which acts through the CCR7 receptor to regulate Treg cell recruitment and retention in peripheral tissues. Glandular and luminal epithelial cells were identified as the major cellular origins of uterine CCL19, and exposure to both seminal plasma and sperm was required for maximum expression. Together, these results indicate that Treg cells accumulate in the uterus prior to embryo implantation and that seminal fluid is a key regulator of the uterine Treg cell population, operating by both increasing the pool of available Treg cells and promoting their CCL19-mediated recruitment from the circulation into the implantation site.

Estradiol and progesterone regulate the migration of mast cells from the periphery to the uterus and induce their maturation and degranulation

BACKGROUND

Mast cells (MCs) have long been suspected as important players for implantation based on the fact that their degranulation causes the release of pivotal factors, e.g., histamine, MMPs, tryptase and VEGF, which are known to be involved in the attachment and posterior invasion of the embryo into the uterus. Moreover, MC degranulation correlates with angiogenesis during pregnancy. The number of MCs in the uterus has been shown to fluctuate during menstrual cycle in human and estrus cycle in rat and mouse indicating a hormonal influence on their recruitment from the periphery to the uterus. However, the mechanisms behind MC migration to the uterus are still unknown.

METHODOLOGY/PRINCIPAL FINDINGS

We first utilized migration assays to show that MCs are able to migrate to the uterus and to the fetal-maternal interface upon up-regulation of the expression of chemokine receptors by hormonal changes. By using a model of ovariectomized animals, we provide clear evidences that also in vivo, estradiol and progesterone attract MC to the uterus and further provoke their maturation and degranulation.

CONCLUSION/SIGNIFICANCE

We propose that estradiol and progesterone modulate the migration of MCs from the periphery to the uterus and their degranulation, which may prepare the uterus for implantation.

Regulation of dendritic cells by female sex steroids: Relevance to immunity and autoimmunity

Dendritic cells (DCs) are critical mediators of adaptive immunity, tolerance and autoimmunity. The human immune system exhibits sexual dimorphism, which is most evident in the female predominance of autoimmune diseases such as systemic lupus erythematosus (SLE). Female sex steroids are strongly implicated in mediating immune sexual dimorphism, in part because estrogen accentuates disease in several models of lupus autoimmunity. In contrast, progesterone may prevent disease development. While much investigation has focused on the effects of estrogen and progesterone on lymphocyte functions, far less attention has been paid to the effects of these hormones on DCs. Current evidence now indicates estrogen can activate DCs, while in contrast, progesterone inhibits DC functions. Thus, we hypothesize that the opposite effects these two hormones have on lupus autoimmunity reflect opposing effects on DC functions. Thus, through direct actions on DCs, female sex steroids may influence autoimmunity, immunity and tolerance.

Tumour necrosis factor alpha stimulates the production of monocyte chemoattractants by extravillous trophoblast cells via differential activation of MAPK pathways

The decidual microenvironment is characterized by a unique population of leukocytes composed primarily of CD56(bright) NK cells and macrophages. The latter are situated near trophoblast cells at the fetal-maternal interface and there is evidence that trophoblast cells are capable of recruiting macrophages to this site. This study sought to determine the role of tumour necrosis factor alpha (TNF) in the trophoblast-mediated recruitment of monocyte-derived macrophages to the fetal-maternal interface. The human first trimester extravillous trophoblast cell line HTR-8/SVneo was shown to express TNFR1 and to secrete the monocyte-attracting chemokines CCL2 and CCL5 after exposure to TNF in a dose-dependent manner. TNF-mediated stimulation of CCL2 secretion was completely inhibited by incubating the trophoblast cells with the p38-MAPK inhibitor SB203580, whereas CCL5 secretion was inhibited by treating the trophoblast cells with inhibitors specific for JNK (SP600125) and ERK kinase (U0126). Media conditioned by TNF-treated trophoblast cells significantly enhanced the ability of the monocyte cell line THP-1 to invade through Matrigel, and this effect was inhibited using antibodies specific for CCL2 and CCL5. These results support a role for TNF at the fetal-maternal interface as a regulator of macrophage recruitment by trophoblast cells.

Alloantigen-enhanced accumulation of CCR5+ 'effector' regulatory T cells in the gravid uterus

Regulatory T cells play an essential role in preventing fetal rejection by the maternal immune system. Here we show that, based on the expression of CCR5, regulatory T cells can be divided into a highly suppressive CCR5+ and a far less suppressive CCR5- subpopulation, suggesting that the former represent the effector arm of regulatory T cells. Although regulatory T cells from CCR5-/- gene deletion mutants still suppress, they are less effective mediators of maternal-fetal tolerance. The accumulation of CCR5+ regulatory T cells at this site appears to be enhanced by alloantigen. This finding is in stark contrast to the systemic expansion of regulatory T cells during pregnancy, which appears to be alloantigen-independent. The fact that CCR5+ regulatory T cells preferentially accumulate in the gravid uterus and that expression of CCR5 on regulatory T cells can be induced by activation lead us to propose that CCR5 is responsible for the accumulation of those regulatory T cells that have been activated by paternal antigens.

Estrogen selectively regulates chemokines in murine splenocytes

Estrogen has striking effects on immunity and inflammatory autoimmune conditions. One potential mechanism of estrogen-induced regulation of immunity and inflammatory autoimmune conditions is by altering the secretion of chemokines by lymphocytes, an aspect not well addressed thus far. We found that estrogen has marked, but differential, effects on the secretion of chemokines from activated splenocytes. Estrogen treatment significantly increased the secretion of MCP-1, MCP-5, eotaxin, and stromal cell-derived factor 1beta from Con A-activated splenocytes when compared with placebo-treated controls, and it had no effects on the levels of RANTES, thymus and activation-regulated chemokine, and keratinocyte-derived chemokine (KC) at 24 h. A kinetic analysis showed that chemokines tended to increase with stimulation time, but only MCP-1 and MCP-5 showed a biological trend of increasing in splenocytes from estrogen-treated mice, and KC was decreased significantly in estrogen-treated splenocytes at 18 h. Estrogen did not affect the protein levels of chemokine receptors CCR1 or CCR2 at 24 h. Estrogen-induced alterations in the levels of MCP-1 and MCP-5 are mediated, in part, by IFN-gamma, as estrogen treatment of IFN-gamma null mice, unlike wild-type mice, did not up-regulate these chemokines. However, addition of recombinant IFN-gamma resulted in markedly increased secretion of MCP-1 and MCP-5 only in the cells derived from estrogen-treated mice. These studies provide novel data indicating that estrogen may promote inflammatory conditions by altering the levels of chemokines, providing evidence for an additional mechanism by which estrogens can regulate inflammation.

17beta-Estradiol inhibits keratinocyte-derived chemokine production following trauma-hemorrhage

Neutrophil infiltration is a key step in the development of organ dysfunction following trauma-hemorrhage (T-H). Although we have previously shown that 17beta-estradiol (E2) prevents neutrophil infiltration and organ damage following T-H, the mechanism by which E2 inhibits neutrophil transmigration remains unknown. We hypothesized that E2 prevents neutrophil infiltration via modulation of keratinocyte-derived chemokine (KC), a major attractant for neutrophils. To examine this, male C3H/HeN mice were subjected to T-H or sham operation and thereafter resuscitated with Ringer lactate and E2 (1 mg/kg body wt) or vehicle. Animals were killed 2 h after resuscitation, and Kupffer cells were isolated. Plasma levels and Kupffer cell production capacities of KC, TNF-alpha, and IL-6 were determined by BD Cytometric Bead Arrays; lung mRNA expression of KC was measured with real-time PCR; myeloperoxidase activity assays were performed to determine neutrophil infiltration, and organ damage was assessed by edema formation. Treatment with E2 decreased systemic levels and restored Kupffer cell production of KC, TNF-alpha, and IL-6, as well as KC gene expression and protein in the lung. This was accompanied with a decrease in neutrophil infiltration and edema formation in the lung. These results suggest that E2 prevents lung neutrophil infiltration and organ damage in part by decreasing KC during posttraumatic immune response.

Uterine and serum cytokine arrays in the mouse during estrus

Cytokines govern uterine immunology and embryo receptivity and are increasingly recognized for their embryotrophic roles. While supplementing culture media with cytokines may improve embryo development/viability in vitro, little is known about their physiological profiles in vivo, and hence which are likely to be uterine immunoregulators and embryotrophins. Therefore, this study profiled 23 cytokines in uterine fluid and serum from individual naturally cycling estrous mice. Samples were analyzed by fluid-phase multiplex immunoassays for interleukin (IL)-1alpha, IL-1beta, IL-2, IL-3, IL-4, IL-5, IL-6, IL-10, IL-12 (p40), IL-12 (p70), IL-13, IL-17, eotaxin, granulocyte-colony stimulating factor (G-CSF), granulocyte macrophage-colony stimulating factor (GM-CSF), interferon (IFN)-gamma, keratinocyte-derived chemokine (KC), monocyte chemoattractant protein (MCP)-1, macrophage inflammatory protein (MIP)-1alpha MIP)-1beta regulated upon activation, normal T-cell expressed and secreted (RANTES) and tumor necrosis factor (TNF)-alpha. There was a marked divergence in cytokine concentrations between uterine fluid and serum. The former was dominated by G-CSF, eotaxin, KC and IL-1alpha, and had significantly higher levels of IL-1beta, IL-2, IL-3, IL-4, IL-6, IL-9, GM-CSF, MIP-1alpha, MIP-1beta and RANTES. Serum had significantly higher IL-12 (p40), IL-12 (p70), IL-17 and IFN-gamma concentrations. No significant differences in IL-5, IL-10, IL-13, MCP-1 or TNF-alpha profiles were noted. These data indicated a strict compartmentalization of uterine cytokines, with G-CSF as a major cytokine at estrous. Results are discussed with respect to immune cell function, post-coital paternal antigen processing, estrous cyclicity, and endometrial angiogenesis, cell turnover and differentiation.

Murine serum cytokines throughout the estrous cycle, pregnancy and post partum period

Cytokines are pleiotropic glycoproteins participating in many aspects of mammalian reproductive physiology. Although murine models have been established to study normal and pathological pregnancy, the small volume of retrievable sample has hampered investigations into the role of cytokines in these processes. These problems were overcome by using fluid-phase multiplex immunoassays to monitor the serum profiles of 18 cytokines in single animals throughout normal murine reproduction: estrus, diestrus, post coitum, preimplantation, implantation, mid-pregnancy, late pregnancy and post partum. Most cytokines were detectable throughout all stages studied. Modest changes in profile were associated with estrous cyclicity and early pregnancy while virtually all cytokine levels increased markedly in mid- to late pregnancy and either fell slightly or levelled off post partum. The functional interrelationships between the various cytokines and the hormonal milieu are discussed with respect to gestational stage. Although certain profiles supported the 'conventional' Th1:Th2 cytokine paradigm of pregnancy, many of the changes recorded were orchestrated around IL-12 (p40) and (p70). The present findings suggest that the traditional cytokine dichotomy poorly describes complex immunological processes like pregnancy.

Regulation of Numbers of Macrophages in the Endometrium of the Sheep by Systemic Effects of Pregnancy, Local Presence of the Conceptus, and Progesterone

Many species exhibiting hemochorial placentation experience an accumulation of macrophages in the endometrium during pregnancy. For the present study, it was tested whether macrophages also accumulate in the endometrium of the sheep, which is a species undergoing an epitheliochorial placentation. An additional objective was to determine whether regulation of endometrial macrophage number occurs via systemic or local signals and whether progesterone is one of these signals. The approach was to evaluate presence of macrophages immunohistochemically using antibodies to CD68 and CD14. Tissues examined were from cyclic ewes in the luteal phase of the estrous cycle, unilaterally-pregnant ewes at day 140 of pregnancy in which pregnancy was surgically confined to one uterine horn, ovariectomized ewes, and ovariectomized ewes treated with progesterone for 44 days. Macrophages were localized predominately to the stromal compartment of the stratum compactum region of the endometrium. In non-pregnant ewes, macrophages were not abundant regardless of physiological status. Increased numbers of endometrial macrophages were seen for both the pregnant and non-pregnant uterine horns of unilaterally pregnant ewes. Numbers of macrophages were higher in the endometrium from the pregnant uterine horn than from endometrium from the non-pregnant uterine horn. Results indicate that macrophages accumulate in the endometrium by day 140 of pregnancy in the sheep and that this induction is because of both systemic and local signals. Progesterone appears not to be an important regulator of numbers of endometrial macrophages.

Regulation of blastocyst migration, apposition, and initial adhesion by a chemokine, interferon gamma-inducible protein 10 kDa (IP-10), during early gestation

For a pregnancy to be established, initial apposition and adhesion of the blastocyst to maternal endometrium must occur in a coordinated manner; however, a key factor(s) that mediates the trophoblast cell migration and attachment to the apical surface of the endometrium has not been identified. In this study, we examined the effect of an endometrial chemokine, interferon-gamma-inducible protein 10 kDa (IP-10), on conceptus migration to the endometrial epithelium. We first studied endometrial IP-10 mRNA expression, which was localized in the subepithelial stromal region, and detected the protein in the uterine flushing media during early pregnancy. Expression of IP-10 mRNA by the endometrium of cyclic animals was stimulated by the addition of a conceptus factor interferon-tau (IFN-tau). Immunofluorescent analysis revealed that IP-10 receptor, CXCR3, was localized in the trophoblast cells, to which biotinylated-recombinant caprine IP-10 (rcIP-10) bound. Chemotaxis assay indicated that rcIP-10 stimulated the migration of trophoblast cells, and the effects of rcIP-10 were neutralized by the pretreatment with an anti-IP-10 antibody. Adhesive activity of trophoblast cells to fibronectin was promoted by rcIP-10, and the effect was inhibited by the use of anti-IP-10 antibody. Further adhesion experiments demonstrated that binding of trophoblast cells to fibronectin was completely inhibited by a peptide of the Arg-Gly-Asp (RGD) sequence, which binds to integrins alpha5beta1, alphaVbeta1, alphaVbeta3, and alphaVbeta5, whereas non-binding peptide containing Arg-Gly-Glu (RGE) had minimal effects. More importantly, rcIP-10 promoted the adhesion of trophoblast cells to primary cells isolated from endometrial epithelium. Furthermore, rcIP-10 stimulated the expression of integrin alpha5, alphaV, and beta3 subunit mRNA in trophoblast cells. These findings suggest that endometrial IP-10 regulates the establishment of apical interactions between trophoblast and epithelial cells during early gestation.

Role of prostaglandin H2 synthase 2 in murine parturition: study on ovariectomy-induced parturition in prostaglandin F receptor-deficient mice

To determine the prostaglandin (PG) H2 synthase (generally referred to as cyclooxygenase [COX]) isozyme responsible for producing uterotonic PGs during parturition, we used PGF2alpha receptor-deficient mice, which exhibit parturition failure due to impaired withdrawal of serum progesterone at term. On ovariectomy-induced parturition in these mice, uterine COX-2 mRNA expression was drastically induced in the myometrium, whereas COX-1 mRNA expression in the endometrial epithelium decreased. The concomitant administration of progesterone with ovariectomy resulted in a delay in parturition and the disappearance of both the increase in COX-2 mRNA and the decrease in COX-1 mRNA. Thus, the expression of myometrial COX-2 and the occurrence of parturition are closely associated in this model. Furthermore, administration of the COX-nonselective inhibitor, indomethacin, or the COX-2-selective inhibitor, Dup-697 or JTE-522, effectively delayed ovariectomy-induced parturition in these mice. These findings suggest that COX-2-derived PGs contribute to the onset of parturition after the decrease in serum progesterone level.

Cytokine cross-talk between mother and the embryo/placenta

Cytokines are regulatory glycoproteins that can affect virtually every cell type in the body and have pleiotropic regulatory effects on hematopoietic, endocrine, nervous and immune systems. Chemokines, although considered as members of the cytokine superfamily, are establishing their own identity. Chemokines mediate leukocyte migration through specific G protein coupled receptors in various tissues. Recently, much evidence has suggested that cytokines and chemokines play a very important role in the reproduction, i.e. embryo implantation, endometrial development, and trophoblast growth and differentiation by modulating the immune and endocrine systems. The close correlation between the embryo and endometrium and between the placenta and decidua are mediated by sex steroid hormones, cytokines and chemokines. As a result of this closely related cross-talk, pregnancy is successfully maintained.

Chemokines and their receptors in the central nervous system

Chemokines are a family of proteins associated with the trafficking of leukocytes in physiological immune surveillance and inflammatory cell recruitment in host defence. They are classified into four classes based on the positions of key cystiene residues: C, CC, CXC, and CX3C. Chemokines act through both specific and shared receptors that all belong to the superfamily of G-protein-coupled receptors. Besides their well-established role in the immune system, several recent reports have demonstrated that these proteins also play a role in the central nervous system (CNS). In the CNS, chemokines are constitutively expressed by microglial cells, astrocytes, and neurons, and their expression can be increased after induction with inflammatory mediators. Constitutive expression of chemokines and chemokine receptors has been observed in both developing and adult brains, and the role played by these proteins in the normal brain is the object of intense study by many research groups. Chemokines are involved in brain development and in the maintenance of normal brain homeostasis; these proteins play a role in the migration, differentiation, and proliferation of glial and neuronal cells. The chemokine stromal cell-derived factor 1 and its receptor, CXCR4, are essential for life during development, and this ligand-receptor pair has been shown to have a fundamental role in neuron migration during cerebellar formation. Chemokine and chemokine receptor expression can be increased by inflammatory mediators, and this has in turn been associated with several acute and chronic inflammatory conditions. In the CNS, chemokines play an essential role in neuroinflammation as mediators of leukocyte infiltration. Their overexpression has been implicated in different neurological disorders, such as multiple sclerosis, trauma, stroke, Alzheimer's disease, tumor progression, and acquired immunodeficiency syndrome-associated dementia. An emerging area of interest for chemokine action is represented by the communication between the neuroendocrine and the immune system. Chemokines have hormone-like actions, specifically regulating the key host physiopathological responses of fever and appetite. It is now evident that chemokines and their receptors represent a plurifunctional family of proteins whose actions on the CNS are not restricted to neuroinflammation. These molecules constitute crucial regulators of cellular communication in physiological and developmental processes.

Estrogen and angiogenesis: A review

Multiple lines of evidence suggest that estrogen directly modulates angiogenesis via effects on endothelial cells. Under physiological conditions, angiogenesis is routinely observed in the uterus in association with fluctuations in the levels of circulating estradiol and other sex steroids. In pathological circumstances, such as breast cancer, a clear association between estrogen, estrogen receptor expression by endothelial cells, angiogenic activity, and/or tumor invasiveness has been made. Studies performed in our laboratory have revealed that estradiol accelerates functional endothelial recovery after arterial injury. Despite these consistent observations, the mechanisms by which estrogen regulates angiogenesis under physiological and pathological circumstances have not been defined.