Neutralization of LPS or blockage of TLR4 signaling prevents stress-triggered fetal loss in murine pregnancy

Vasopressin as Possible Treatment Option in Autism Spectrum Disorder

Autism spectrum disorder (ASD) is rather common, presenting with prevalent early problems in social communication and accompanied by repetitive behavior. As vasopressin was implicated not only in salt-water homeostasis and stress-axis regulation, but also in social behavior, its role in the development of ASD might be suggested. In this review, we summarized a wide range of problems associated with ASD to which vasopressin might contribute, from social skills to communication, motor function problems, autonomous nervous system alterations as well as sleep disturbances, and altered sensory information processing. Beside functional connections between vasopressin and ASD, we draw attention to the anatomical background, highlighting several brain areas, including the paraventricular nucleus of the hypothalamus, medial preoptic area, lateral septum, bed nucleus of stria terminalis, amygdala, hippocampus, olfactory bulb and even the cerebellum, either producing vasopressin or containing vasopressinergic receptors (presumably V1a). Sex differences in the vasopressinergic system might underline the male prevalence of ASD. Moreover, vasopressin might contribute to the effectiveness of available off-label therapies as well as serve as a possible target for intervention. In this sense, vasopressin, but paradoxically also V1a receptor antagonist, were found to be effective in some clinical trials. We concluded that although vasopressin might be an effective candidate for ASD treatment, we might assume that only a subgroup (e.g., with stress-axis disturbances), a certain sex (most probably males) and a certain brain area (targeting by means of virus vectors) would benefit from this therapy.

Climate change and pregnancy complications: From hormones to the immune response

Pregnant women are highly vulnerable to adverse environments. Accumulating evidence highlights that increasing temperatures associated with the ongoing climate change pose a threat to successful reproduction. Heat stress caused by an increased ambient temperature can result in adverse pregnancy outcomes, e.g., preterm birth, stillbirth and low fetal weight. The pathomechanisms through which heat stress interferes with pregnancy maintenance still remain vague, but emerging evidence underscores that the endocrine system is severely affected. It is well known that the endocrine system pivotally contributes to the physiological progression of pregnancy. We review – sometimes speculate - how heat stress can offset hormonal dysregulations and subsequently derail other systems which interact with hormones, such as the immune response. This may account for the heat-stress related threat to successful pregnancy progression, fetal development and long-term children’s health.

Toll-like receptor-4 null mutation causes fetal loss and fetal growth restriction associated with impaired maternal immune tolerance in mice

Maternal immune adaptation to accommodate pregnancy depends on sufficient availability of regulatory T (Treg) cells to enable embryo implantation. Toll-like receptor 4 is implicated as a key upstream driver of a controlled inflammatory response, elicited by signals in male partner seminal fluid, to initiate expansion of the maternal Treg cell pool after mating. Here, we report that mice with null mutation in Tlr4 (Tlr4^−/−) exhibit impaired reproductive outcomes after allogeneic mating, with reduced pregnancy rate, elevated mid-gestation fetal loss, and fetal growth restriction, compared to Tlr4^+/+ wild-type controls. To investigate the effects of TLR4 deficiency on early events of maternal immune adaptation, TLR4-regulated cytokines and immune regulatory microRNAs were measured in the uterus at 8 h post-mating by qPCR, and Treg cells in uterus-draining lymph nodes were evaluated by flow cytometry on day 3.5 post-coitum. Ptgs2 encoding prostaglandin-endoperoxide synthase 2, cytokines Csf2, Il6, Lif, and Tnf, chemokines Ccl2, Cxcl1, Cxcl2, and Cxcl10, and microRNAs miR-155, miR-146a, and miR-223 were induced by mating in wild-type mice, but not, or to a lesser extent, in Tlr4^−/− mice. CD4⁺ T cells were expanded after mating in Tlr4^+/+ but not Tlr4^−/− mice, with failure to expand peripheral CD25⁺FOXP3⁺ NRP1⁻ or thymic CD25⁺FOXP3⁺ NRP1⁺ Treg cell populations, and fewer Treg cells expressed Ki67 proliferation marker and suppressive function marker CTLA4. We conclude that TLR4 is an essential mediator of the inflammation-like response in the pre-implantation uterus that induces generation of Treg cells to support robust pregnancy tolerance and ensure optimal fetal growth and survival.

Decidual cells are the initial target of polyriboinosinic-polyribocytidylic acid in a mouse model of maternal viral infection

Background

Maternal immune activation has been implicated in the pathophysiology of neurodevelopmental disorders such as autism spectrum disorders caused by maternal infection. It has been suggested that the placental origin of inflammatory cytokines leads to neurodevelopmental disorders. However, the identity of the initial immune-activated site in the placenta, in response to maternal viral infection, is not clear.

Methods

By cross-breeding male enhanced green fluorescent protein (EGFP) transgenic mice with wild-type females, the placental tissues of maternal origin can be distinguished from those of paternal origin by EGFP expression. Using this method, at embryonic day (E) 12.5, dams were administered an intraperitoneal polyriboinosinic-polyribocytidylic acid (poly [I:C]) injection. We quantitatively analyzed the levels of phosphorylated interferon (IFN) regulatory factor 3 (pIRF3) in the placenta, and investigated the distribution of pIRF3 positive cells.

Results

We show that maternally derived decidual cells are the initial target of maternal poly (I:C) through the toll-like receptor 3/TIR-domain-containing the adapter-inducing interferon-β signaling pathway. We also show that the expression of interferon-β was upregulated in the placenta after maternal injection with poly (I:C).

Conclusion

These results suggest that maternally derived decidual cells are the initial target of maternal poly (I:C) and that this innate immune response is likely associated with a state of maternal immune activation.

Definition and Multiple Factors of Recurrent Spontaneous Abortion

Recurrent spontaneous abortion (RSA) is usually defined as three or more spontaneous abortions prior to 20-28 weeks gestation. RSA affects approximately 2-5% of all women of childbearing age, and it brings tremendous psychological and psychiatric trauma to the women and also results in economic burden. The causes could be female age, anatomical and chromosomal abnormalities, genetic, endocrinological, placental anomalies, infection, smoking and alcohol consumption, psychological factor, exposure to environmental factors such as heavy metal, environment pollution, and radiation.

Gut microbes in neurocognitive and mental health disorders

INTRODUCTION

As individuals age, the prevalence of neurocognitive and mental health disorders increases. Current biomedical treatments do not completely address the management of these conditions. Despite new pharmacological therapy the challenges of managing these diseases remain.There is increasing evidence that the Gut Microbiome (GM) and microbial dysbiosis contribute to some of the more prevalent mental health and neurocognitive disorders, such as depression, anxiety, obsessive-compulsive disorder (OCD), post-traumatic stress disorder (PTSD), schizophrenia, bipolar disorder (BP), and dementia as well as the behavioural and psychological symptoms of dementia (BPSD) through the microbiota-gut-brain axis. Methodology: Scoping review about the effect of gut microbiota on neurocognitive and mental health disorders.

RESULTS

This scoping review found there is an evolving evidence of the involvement of the gut microbiota in the pathophysiology of neurocognitive and mental health disorders. This manuscript also discusses how the psychotropics used to treat these conditions may have an antimicrobial effect on GM, and the potential for new strategies of management with probiotics and faecal transplantation.

CONCLUSIONS

This understanding can open up the need for a gut related approach in these disorders as well as unlock the door for the role of gut related microbiota management. KEY MESSAGES Challenges of managing mental health conditions remain in spite of new pharmacological therapy. Gut dysbiosis is seen in various mental health conditions. Various psychotropic medications can have an influence on the gut microbiota by their antimicrobial effect.

Role of galectin-glycan circuits in reproduction: from healthy pregnancy to preterm birth (PTB)

Growing evidence suggests that galectins, an evolutionarily conserved family of glycan-binding proteins, fulfill key roles in pregnancy including blastocyst implantation, maternal-fetal immune tolerance, placental development, and maternal vascular expansion, thereby establishing a healthy environment for the growing fetus. In this review, we comprehensively present the function of galectins in shaping cellular circuits that characterize a healthy pregnancy. We describe the current understanding of galectins in term and preterm labor and discuss how the galectin-glycan circuits contribute to key immunological pathways sustaining maternal tolerance and preventing microbial infections. A deeper understanding of the glycoimmune pathways regulating early events in preterm birth could offer the broader translational potential for the treatment of this devastating syndrome.

Steroids, Pregnancy and Fetal Development

Maternal glucocorticoids critically rise during pregnancy reaching up to a 20-fold increase of mid-pregnancy concentrations. Concurrently, another steroid hormone, progesterone, increases. Progesterone, which shows structural similarities to glucocorticoids, can bind the intracellular glucocorticoid receptor, although with lower affinity. Progesterone is essential for the establishment and continuation of pregnancy and it is generally acknowledged to promote maternal immune tolerance to fetal alloantigens through a wealth of immunomodulatory mechanisms. Despite the potent immunomodulatory capacity of glucocorticoids, little is known about their role during pregnancy. Here we aim to compare general aspects of glucocorticoids and progesterone during pregnancy, including shared common steroidogenic pathways, plasma transporters, regulatory pathways, expression of receptors, and mechanisms of action in immune cells. It was recently acknowledged that progesterone receptors are not ubiquitously expressed on immune cells and that pivotal features of progesterone induced- maternal immune adaptations to pregnancy are mediated via the glucocorticoid receptor, including e.g., T regulatory cells expansion. We hypothesize that a tight equilibrium between progesterone and glucocorticoids is critically required and recapitulate evidence supporting that their disequilibrium underlie pregnancy complications. Such a disequilibrium can occur, e.g., after maternal stress perception, which triggers the release of glucocorticoids and impair progesterone secretion, resulting in intrauterine inflammation. These endocrine misbalance might be interconnected, as increase in glucocorticoid synthesis, e.g., upon stress, may occur in detriment of progesterone steroidogenesis, by depleting the common precursor pregnenolone. Abundant literature supports that progesterone deficiency underlies pregnancy complications in which immune tolerance is challenged. In these settings, it is largely yet undefined if and how glucocorticoids are affected. However, although progesterone immunomodulation during pregnancy appear to be chiefly mediated glucocorticoid receptors, excess glucocorticoids cannot compensate by progesterone deficiency, indicating that additional und still undercover mechanisms are at play.

The Relationship Between Perinatal Mental Health and Stress: a Review of the Microbiome

PURPOSE OF REVIEW

Our current understanding of the underlying mechanisms and etiologies of perinatal mood and anxiety disorders (PMADs) is not clearly identified. The relationship of stress-induced adaptations (i.e., the hypothalamic-pituitary-adrenal (HPA) axis, the autonomic nervous system (ANS), the immune system) and the microbiota are potential contributors to psychopathology exhibited in women during pregnancy and postpartum and should be investigated.

RECENT FINDINGS

The stress response activates the HPA axis and dysregulates the ANS, leading to the inhibition of the parasympathetic system. Sustained high levels of cortisol, reduced heart variability, and modulated immune responses increase the vulnerability to PMAD. Bidirectional communication between the nervous system and the microbiota is an important factor to alter host homeostasis and development of PMAD. Future research in the relationship between the psychoneuroimmune system, the gut microbiota, and PMAD has the potential to be integrated in clinical practice to improve screening, diagnosis, and treatment.

Expression of TLR4 and its effect on Treg cells in early pregnancy decidual stromal cells after lipopolysaccharide treating

OBJECTIVE

To investigate the expression of TLR4 in human early pregnancy decidual stromal cells (DSCs) induced by lipopolysaccharide (LPS) and its effect on the peripheral blood regulatory T (Treg) cells subgroup in women of childbearing age.

METHOD

Isolating and cultivating normal human early pregnancy DSCs followed by treatment with 0, 25, 50, 100 and 200 ng/ml LPS, and the expression level of TLR4 mRNA was detected by RT-PCR. After 3 or 4 generation we divide the DSCs into 5 groups: ①Control group: Cultivation of peripheral blood lymphocyte (PBLC); ②Co-cultivation group: Co-cultivation of PBLC and DSCs; ③LPS stimulation group: PBLC + DSCs + LPS; ④PDTC blocking-up group: PBLC + DSCs + LPS + PDTC; ⑤TLR4 blocking-up group: PBLC + DSCs + LPS + TLR4mAb. In ①-④ groups, western blot was used to detect the expression of inhibitory factor-κB (IκB-α) protein and RT-PCR was used to detect the expression of FoxP3 mRNA. In ①-⑤ groups, flow cytometry was applied to detect the percentage of Treg cells subgroup.

RESULTS

The purity of primary cultured DSCs was more than 95%. RT-PCR results showed that the expression level of TLR4 mRNA increased gradually with the augment of LPS concentration. Western blot and RT-PCR showed that the expression of IκBα protein and FoxP3 mRNA in the other 3 groups was significantly higher than that in the control group (P <  0.05), and the expression of IκBα protein and FoxP3 mRNA in LPS stimulation group was lower than that in the co-cultivation group (P <  0.05). Compared with the LPS stimulation group, the expression of IκBα protein and FoxP3 mRNA in PDTC blocking-up group was higher than that in the LPS stimulation group (P <  0.05), but still lower than the co-cultivation group (P <  0.05). The proportion of Treg cells in the other 4 groups detected by flow cytometry was significantly higher than that in the control group (P <  0.05). Compared with the co-cultivation group, the Treg cells ratio of the LPS stimulation group was significantly decreased (P <  0.05). The proportions of Treg cells in PDTC blocking-up group and TLR4 blocking-up group were higher than that in the LPS stimulation group, but still lower than that in the co-cultivation group (P <  0.05). There was no significant difference between the PDTC blocking-up group and the TLR4 blocking-up group (P > 0.05).

CONCLUSION

Human early pregnancy DSCs can promote the differentiation of Treg cells. LPS can stimulate the expression of TLR4 in early pregnancy DSCs and decrease the proportion of Treg cells in PBLC, with NF-κB signaling pathway being the potential underlying mechanisms.

Prenatal Immune and Endocrine Modulators of Offspring's Brain Development and Cognitive Functions Later in Life

Milestones of brain development in mammals are completed before birth, which provide the prerequisite for cognitive and intellectual performances of the offspring. Prenatal challenges, such as maternal stress experience or infections, have been linked to impaired cognitive development, poor intellectual performances as well as neurodevelopmental and psychiatric disorders in the offspring later in life. Fetal microglial cells may be the target of such challenges and could be functionally modified by maternal markers. Maternal markers can cross the placenta and reach the fetus, a phenomenon commonly referred to as “vertical transfer.” These maternal markers include hormones, such as glucocorticoids, and also maternal immune cells and cytokines, all of which can be altered in response to prenatal challenges. Whilst it is difficult to discriminate between the maternal or fetal origin of glucocorticoids and cytokines in the offspring, immune cells of maternal origin—although low in frequency—can be clearly set apart from offspring's cells in the fetal and adult brain. To date, insights into the functional role of these cells are limited, but it is emergingly recognized that these maternal microchimeric cells may affect fetal brain development, as well as post-natal cognitive performances and behavior. Moreover, the inheritance of vertically transferred cells across generations has been proposed, yielding to the presence of a microchiome in individuals. Hence, it will be one of the scientific challenges in the field of neuroimmunology to identify the functional role of maternal microchimeric cells as well as the brain microchiome. Maternal microchimeric cells, along with hormones and cytokines, may induce epigenetic changes in the fetal brain. Recent data underpin that brain development in response to prenatal stress challenges can be altered across several generations, independent of a genetic predisposition, supporting an epigenetic inheritance. We here discuss how fetal brain development and offspring's cognitive functions later in life is modulated in the turnstile of prenatal challenges by introducing novel and recently emerging pathway, involving maternal hormones and immune markers.

Emerging literature in the Microbiota-Brain Axis and Perinatal Mood and Anxiety Disorders

Perinatal Mood and Anxiety Disorders (PMAD) are common and can cause significant morbidity and mortality for mother and child. A healthy perinatal period requires significant adaptations; however, systems can become imbalanced resulting in depressive and anxiety symptoms. The interface between the microbiome, the immune system, and the stress system may be a model for understanding mechanisms underlying PMAD. Emerging literature from general populations regarding immune, hormone, and HPA axis changes in relation to the microbiome combined with literature on immune, gonadotropin, and stress systems in the perinatal period provides a background. We systematically investigated literature in the developing field of the microbiome in relation to PMAD. Our inclusion criteria were 1) reporting measure of maternal mood, stress, or anxious or depressed behavior; 2) in the perinatal period, defined as pregnancy through one year postpartum; and 3) reporting measure of maternal microbiome including manipulations of the microbiome through prebiotics, probiotics, or interventions with microbial byproducts. The review identified research studying associations between stress and maternal microbiome; dietary impacts on microbial composition, mood, and stress; and the relationship between the microbiome and the immune system through immunoregulatory mechanisms. Important themes identified include: the importance of studying the maternal microbiome and measures of stress, anxiety, and depression and that multi-hit models will be needed as research strives to determine the effects of multiple mechanisms working in concert.

Maternal socioeconomic disadvantage is associated with transcriptional indications of greater immune activation and slower tissue maturation in placental biopsies and newborn cord blood

Children from economically disadvantaged families experience worse cognitive, psychiatric, and medical outcomes compared to more affluent youth. Preclinical models suggest some of the adverse influence of disadvantage could be transmitted during gestation via maternal immune activation, but this hypothesis has not been tested in humans. It also remains unclear whether prenatal interventions can mitigate such effects. To fill these gaps, we conducted two studies. Study 1 characterized the socioeconomic conditions of 79 women during pregnancy. At delivery, placenta biopsies and umbilical blood were collected for transcriptional profiling. Maternal disadvantage was associated with a transcriptional profile indicative of higher immune activation and slower fetal maturation, particularly in pathways related to brain, heart, and immune development. Cord blood cells of disadvantaged newborns also showed indications of immaturity, as reflected in down-regulation of pathways that coordinate myeloid cell development. These associations were independent of fetal sex, and characteristics of mothers (age, race, adiposity, diabetes, pre-eclampsia) and babies (delivery method, gestational age). Study 2 performed the same transcriptional analyses in specimens from 20 women participating in CenteringPregnancy, a group-based psychosocial intervention, and 20 women in traditional prenatal care. In both placenta biopsies and cord blood, women in CenteringPregnancy showed up-regulation of transcripts found in Study 1 to be most down-regulated in conjunction with disadvantage. Collectively, these results suggest socioeconomic disparities in placental biology are evident at birth, and provide clues about the mechanistic origins of health disparities. They also suggest the possibility that psychosocial interventions could have mitigating influences.

Acoustic stress induces long term severe intestinal inflammation in the mouse

The influence of noise on the presentation and progression of inflammatory bowel diseases has been poorly analyzed. We designed this study to investigate immediate and late effects of acoustic stress (AS) on small intestine. To this aim, CBA/J, BALB/c and DBA/2 mice were divided into AS and control groups. AS mice were exposed to noise (300Hz-70dB) during 24hs and randomized into: A) Acute effects group: mice were killed after AS; L) Late effects group: mice were killed 3 weeks after AS and O) Over-exposed effects group: mice were submitted to AS once a week during a month and killed. Small intestine sections were histologically examined. The expression of cytokines (IL-17, IL-22, TNF-α, INF-ɣ and TGF-β), CCL-25 and Ki67 was studied by immunohistochemistry and immunofluorescence techniques. "A" group displayed short and fragmented villi, diminished number of lamina propria cells, leucocyte infiltration, higher number of goblet cells and predominance of IL-17 expression. "L" group showed epithelial proliferative foci (CCL25+Ki67+) and increased TNFα/TGF-β expression. Tissue damage was aggravated in "O" group. In conclusion, AS is able to trigger a severe intestinal inflammatory process in healthy mice, which spontaneously amplifies and perpetuates. Noise might be harmful to humans by aggravating inflammatory bowel diseases.

Estradiol Suppresses TLR4-triggered Apoptosis of Decidual Stromal Cells and Drives an Anti-inflammatory TH2 Shift by Activating SGK1

A pro-inflammatory cytokine profile at the feto-maternal interface may predispose immune maladaptation notably in early miscarriages. We investigated the involvement of estradiol (E2)-activated serum-glucocorticoid regulated kinase 1 (SGK1) in preserving the tolerogenic and pro-survival intrauterine microenvironment beneficial to gestation maintenance. Decidual SGK1 was down-regulated in early miscarriage, consistent with the lower serum E2 concentration seen in pregnancy loss. Lipopolysaccharide (LPS)/Toll-like receptors 4 (TLR4) signaling induced apoptosis and the pro-inflammatory T helper type (TH) 1 response of decidual stromal cells (DSCs) were associated with miscarriage. SGK1 activation was suppressed by LPS/TLR4 signaling and would be rescued by E2 administration via the PI3K signaling pathway in DSCs. SGK1 activation attenuated TLR4-mediated cell apoptosis, while promoting cell viability of DSCs by up-regulating the pro-survival genes BCL2 and XIAP, and enhancing the phosphorylation of FOXO1. Furthermore, E2-induced SGK1 activation reduced the secretion of pro-inflammatory TH1 cytokines, and promoted the generation of TH2 cytokines and elevated IRF4 mRNA and protein levels in LPS-incubated DSCs. Pharmacologic inhibition of SGK1 or suppression by small interfering (si) RNA increased the phosphorylation and nuclear translocation of NF-κB to reverse the pro-TH2 and anti-inflammatory effects of E2 pretreatment, leading to compromised pregnancy. These findings suggest that the E2-mediated SGK1 activation suppressed LPS-mediated apoptosis and promoted the anti-inflammatory TH2 responses in DSCs, ultimately contributing to a successful pregnancy.

Novel Toll-like receptor-4 antagonist (+)-naloxone protects mice from inflammation-induced preterm birth

Toll-like receptor 4 (TLR4) activation by bacterial infection, or by sterile inflammatory insult is a primary trigger of spontaneous preterm birth. Here we utilize mouse models to investigate the efficacy of a novel small molecule TLR4 antagonist, (+)-naloxone, the non-opioid isomer of the opioid receptor antagonist (−)-naloxone, in infection-associated preterm birth. Treatment with (+)-naloxone prevented preterm delivery and alleviated fetal demise in utero elicited by i.p. LPS administration in late gestation. A similar effect with protection from preterm birth and perinatal death, and partial correction of reduced birth weight and postnatal mortality, was conferred by (+)-naloxone administration after intrauterine administration of heat-killed E. coli. Local induction by E. coli of inflammatory cytokine genes Il1b, Il6, Tnf and Il10 in fetal membranes was suppressed by (+)-naloxone, and cytokine expression in the placenta, and uterine myometrium and decidua, was also attenuated. These data demonstrate that inhibition of TLR4 signaling with the novel TLR4 antagonist (+)-naloxone can suppress the inflammatory cascade of preterm parturition, to prevent preterm birth and perinatal death. Further studies are warranted to investigate the utility of small molecule inhibition of TLR-driven inflammation as a component of strategies for fetal protection and delaying preterm birth in the clinical setting.

Identification of suitable reference genes in the mouse placenta

INTRODUCTION

Quantitative real-time reverse transcription polymerase chain reaction (RT-qPCR) is a reliable tool to analyse gene expression profiles. The expression of housekeeping genes generally serves as a reference for mRNA amount, assuming that it remains stable under pathophysiological and experimental conditions. To date, an empirical validation of reference genes suitable for RT-qPCR-based studies in the mouse placenta is missing.

METHODS

We used NormFinder and BestKeeper statistical software to analyse the expression stability of candidate housekeeping genes quantified by RT-qPCR in mouse placentas.

RESULTS

Fifteen of 32 potential candidate housekeeping genes analysed on gestation day (gd) 16.5 in mouse placentas exhibited an optimal cycle threshold (Ct). Among them B2m, Polr2a, Ubc, and Ywhaz genes showed the highest expression stability in placentas from control, but also experimentally-challenged mice. These genes as well as the currently widely used housekeeping genes Hprt1, Actb, and Gapdh were selected for further quality assessments. We quantified the Ct values of these selected genes in placental samples obtained from wild-type or genetically engineered dams at different gds, or upon selected experimental interventions known to affect placental phenotype. Among all housekeeping genes analysed, Polr2a was the most stably expressed and its expression stability excelled in combination with Ubc.

DISCUSSION

Polr2a, especially in combination with Ubc, can be proposed as highly suitable endogenous reference for gene expression analysis in mouse-derived placental tissue. Moreover, the validation of both genes as a stable reference gene in human placenta-derived tissue strengthens the translational relevance of RT-qPCR findings using mouse placenta.

Nutrient availability, the microbiome, and intestinal transport during pregnancy

Adequate adaptation of the gastrointestinal tract is important during pregnancy to ensure that the increased metabolic demands by the developing fetus are met. These include changes in surface area mediated by villus hypertrophy and enhanced functional capacity of individual nutrient receptors, including those transporting glucose, fructose, leucine, and calcium. These processes are regulated either by the enhanced nutrient demand or are facilitated by changes in the secretion of pregnancy hormones. Our review also covers recent research into the microbiome, and how pregnancy could lead to microbial adaptations, which are beneficial to the mother, yet are also similar to those seen in the metabolic syndrome. The potential role of diet in modulating the microbiome during pregnancy, as well as the potential for the intestinal microbiota to induce pregnancy complications, are examined. Gaps in the current literature are highlighted, including those where only historical evidence is available, and we suggest areas that should be a priority for further research. In summary, although a significant degree of adaptation has been described, there are both well-established processes and more recent discoveries, such as changes within the maternal microbiome, that pose new questions as to how the gastrointestinal tract effectively adapts to pregnancy, especially in conjunction with maternal obesity.

Tim-3 protects decidual stromal cells from toll-like receptor-mediated apoptosis and inflammatory reactions and promotes Th2 bias at the maternal-fetal interface

Toll-like receptors (TLRs) are important in mediating immune responses against various pathogens during pregnancy. However, uncontrolled TLR-triggered inflammation will endanger normal pregnancy, resulting in pregnancy loss. Therefore, maintenance of a moderate inflammatory response is crucial for successful pregnancy under conditions of infection. Here, we demonstrated significantly lowered expression of T-cell immunoglobulin and mucin domain 3 (Tim-3) in miscarried decidual stromal cells (DSCs), indicating that Tim-3 might play important roles in maintaining successful pregnancies. Activation of TLR signaling induced pro-inflammatory cytokine production and apoptosis of DSCs, which was accompanied by up-regulated Tim-3 expression. Tim-3, in turn, protected DSCs from TLR-mediated apoptosis in an ERK1/2 pathway-dependent manner. In addition, Tim-3 inhibited TLR signaling-induced inflammatory cytokine production by DSCs through suppressing NF-κB activation. Tim-3 increased production of T helper 2 (Th2)-type cytokines by DSCs and reversed the inhibitory effect of LPS on Th2 cytokine generation by up-regulation of interferon regulatory factor 4 expression. Tim-3 blockade abolished the effect of Tim-3 on the inflammatory response to LPS stimulation. Thus, Tim-3 signaling could represent a “self-control” mechanism in TLR-triggered inflammation during pregnancy. These findings identify Tim-3 as a key regulator of DSCs and suggest its potential as a target for the treatment of spontaneous abortion.

The activating effect of IFN-γ on monocytes/macrophages is regulated by the LIF-trophoblast-IL-10 axis via Stat1 inhibition and Stat3 activation

Interferon gamma (IFN-γ) and leukemia inhibitory factor (LIF) are key gestational factors that may differentially affect leukocyte function during gestation. Because IFN-γ induces a pro-inflammatory phenotype in macrophages and because trophoblast cells are principal targets of LIF in the placenta, we investigated whether and how soluble factors from trophoblast cells regulate the effects of IFN-γ on macrophage activation. IFN-γ reduces macrophage motility, but enhances Stat1 activation, pro-inflammatory gene expression and cytotoxic functions. Soluble factors from villous cytotrophoblasts (vCT+LIF cells) and BeWo cells (BW/ST+LIF cells) that were differentiated in the presence of LIF inhibit macrophage Stat1 activation but inversely sustain Stat3 activation in response to IFN-γ. vCT+LIF cells produce soluble factors that induce Stat3 activation; this effect is partially abrogated in the presence of neutralizing anti-interleukin 10 (IL-10) antibodies. Moreover, soluble factors from BW/ST+LIF cells reduce cell proliferation but enhance the migratory responses of monocytes. In addition, these factors reverse the inhibitory effect of IFN-γ on monocyte/macrophage motility. BW/ST+LIF cells also generate IFN-γ-activated macrophages with enhanced IL-10 expression, but reduced tumor-necrosis factor alpha (TNF-α), CD14 and CD40 expression as well as impaired cytotoxic function. Additional assays performed in the presence of neutralizing anti-IL-10 antibodies and exogenous IL-10 demonstrate that reduced macrophage cytotoxicity and proliferation, but increased cell motility result from the ability of trophoblast IL-10 to sustain Stat3 activation and suppress IFN-γ-induced Stat1 activation. These in vitro studies are the first to describe the regulatory role of the LIF-trophoblast-IL-10 axis in the process of macrophage activation in response to pro-inflammatory cytokines.

Reduced levels of maternal progesterone during pregnancy increase the risk for allergic airway diseases in females only

Observational as well as experimental studies support that prenatal challenges seemed to be associated with an increased risk for allergic airway diseases in the offspring. However, insights into biomarkers involved in mediating this risk are largely elusive. We here aimed to test the association between endogenous and exogenous factors documented in pregnant women, including psychosocial, endocrine, and life style parameters, and the risk for allergic airway diseases in the children later in life. We further pursued to functionally test identified factors in a mouse model of an allergic airway response. In a prospectively designed pregnancy cohort (n = 409 families), women were recruited between the 4th and 12th week of pregnancy. To investigate an association between exposures during pregnancy and the incidence of allergic airway disease in children between 3 and 5 years of age, multiple logistic regression analyses were applied. Further, in prenatally stressed adult offspring of BALB/c-mated BALB/c female mice, asthma was experimentally induced by ovalbumin (OVA) sensitization. In addition to the prenatal stress challenge, some pregnant females were treated with the progesterone derivative dihydrodydrogesterone (DHD). In humans, we observed that high levels of maternal progesterone in early human pregnancies were associated with a decreased risk for an allergic airway disease (asthma or allergic rhinitis) in daughters (adjusted OR 0.92; 95% confidence interval [CI] 0.84 to 1.00) but not sons (aOR 1.02, 95% CI 0.94-1.10). In mice, prenatal DHD supplementation of stress-challenged dams attenuated prenatal stress-induced airway hyperresponsiveness exclusively in female offspring. Reduced levels of maternal progesterone during pregnancy-which can result from high stress perception-increase the risk for allergic airway diseases in females but not in males. Key messages: Lower maternal progesterone during pregnancy increases the risk for allergic airway disease only in female offspring. Prenatal progesterone supplementation ameliorates airway hyperreactivity in prenatally stressed murine offspring.

Immunological modes of pregnancy loss: inflammation, immune effectors, and stress

Inflammatory immune response plays a key role in reproductive failures such as multiple implantation failures (MIF), early pregnancy loss, and recurrent pregnancy losses (RPL). Cellular immune responses particularly mediated by natural killer (NK), and T cells are often dysregulated in these conditions. Excessive or inappropriate recruitment of peripheral blood NK cells to the uterus may lead to cytotoxic environment in utero, in which proliferation and differentiation of trophoblast is hampered. In addition, inadequate angiogenesis by uterine NK cells often leads to abnormal vascular development and blood flow patterns, which, in turn, leads to increased oxidative stress or ischemic changes in the invading trophoblast. T-cell abnormalities with increased Th1 and Th17 immunity, and decreased Th2 and T regulatory immune responses may play important roles in RPL and MIF. A possible role of stress in inflammatory immune response is also reviewed.

The immune privilege of testis and gravid uterus: same difference?

The fetus in the gravid uterus and the developing spermatogenic cells in the adult testis both comprise special challenges for the host immune system. Protection of the neoantigens of the fetus and male germ cells from immune attack, defined as immune privilege, is fundamental for the propagation of species. Immune privilege is not simply the absence of leukocytes, but involves immune and non-immune cells acting synergistically together at multiple levels to create a unique tolerogenic environment. A number of the pathways are shared by the testis and gravid uterus. Amongst them steroid hormones, namely testosterone in the male and progesterone in the female, seem to function as key molecules that govern the local production of immunoregulatory factors which finally control the overall immune environment.

Potential influence of the microbiome on infertility and assisted reproductive technology

Although an altered vaginal microbiota has been demonstrated to affect parturition, its role in assisted reproductive technologies is uncertain. Nevertheless, the effect of known pathogens such as Mycoplasma tuberculosis, Chlamydia trachomatis, and Neisseria gonorrhoeae is clear, causing subclinical changes thought to be risk factors in subfertility. The Human Microbiome Project (HMP) has allowed for metagenomic studies to aid in characterizing normal vaginal flora. Recent findings from the HMP demonstrate that many different species of Lactobacillus are present in the vaginal tract, with a few that predominate. Studies that characterize the vaginal microbiome in assisted reproductive technology support the hypothesis that colonizing the transfer-catheter tip with Lactobacillus crispatus at the time of embryo transfer may increase the rates of implantation and live birth rate while decreasing the rate of infection. In addition, there is some evidence that a progesterone-resistant endometrium might increase the risk of an abnormal vaginal microbiome.

Diet-induced obesity may affect the uterine immune environment in early-mid pregnancy, reducing NK-cell activity and potentially compromising uterine vascularization

OBJECTIVES

To investigate the effect of obesity in early-mid pregnancy on crucial pregnancy hormones and the uterine immune environment.

BACKGROUND

Obesity impacts reproductive ability, adversely affecting conception and leading to complications in pregnancy. Obesity is often regarded as a stress state and an immune disease, both of which may contribute to pregnancy failure. We previously demonstrated that stress in early pregnancy greatly alters progesterone secretion. As progesterone is an immunomodulator, altered progesterone secretion may adversely modify the maternal immune system. In the current study, we test the hypothesis that obesity during pregnancy adversely alters the uterine immune environment.

METHODS

An obese mouse model was created by feeding C57/BL6 mice on a high-fat (HF)/sugar diet for 12 weeks before pregnancy. Control mice were fed on lower-fat/sugar chow. Mice were mated, and on day 7.5 of pregnancy plasma progesterone and prolactin were measured by immunoassay. Cells from the uterus-draining inguinal lymph nodes were collected for analysis of the uterine immune response by flow cytometry.

RESULTS

Diet-induced obesity increased the secretion of progesterone and altered a number of uterine natural killer (NK)- and T-cell responses. These included a marked reduction in the percentage of leucocyte-derived NK cells and reduced expression of interferon-γ (IFN-γ) in the NK cells compared with control mice.

CONCLUSIONS

Maternal obesity, induced by an HF diet, may lead to a reduction in the expression of IFN-γ in NK cells. NK-cell-derived IFN-γ is reported to be involved in supporting uterine spiral artery remodelling. Thus, obesity in early pregnancy may compromise vascularization by reducing the expression of IFN-γ-positive NK cells. Furthermore, the expression of uterine CD8(+) cells was reduced in the HF diet-fed mice, suggesting obesity may adversely alter the maternal immune adaptation that is essential for effective pregnancy.

LPS induces IL-8 expression through TLR4, MyD88, NF-kappaB and MAPK pathways in human dental pulp stem cells

AIM

To evaluate the effects of lipopolysaccharide (LPS) on interleukin-8 (IL-8) and related intracellular signalling pathways in human dental pulp stem cells (hDPSCs).

METHODOLOGY

Human pulp tissues were isolated from human impacted third molars, and the hDPSCs were cultured and characterized. The effects of LPS on IL-8 and Toll-like receptor 4 (TLR4) gene expression in hDPSCs were investigated using real-time quantitative RT-PCR and ELISA. Whether TLR4/MyD88/NF-кB was involved in the LPS-induced up-regulation of IL-8 in hDPSCs was determined using transient transfection, luciferase assay and ELISA. The involvement of MAPKs in the LPS-induced up-regulation of IL-8 in hDPSCs was investigated via transient transfection, luciferase assay, ELISA and western blot. The data were statistically analysed using Student's t-test or one-way anova followed by the Student-Neumann-Keuls test.

RESULTS

Cells exposed to LPS not only displayed an enhanced expression of TLR4 but also showed an elevated IL-8 gene expression; exposure to LPS also resulted in the induction of IL-8 gene transcription via promoter activation. The LPS-induced IL-8 promoter activation was inhibited through dominant-negative mutations in TLR4 and MyD88, but not in TLR2. The LPS-induced IL-8 protein release was attenuated through the administration of TLR4-neutralizing antibody or MyD88 inhibitory peptide and a dominant-negative mutation in IκBα. In contrast, IL-8 protein release was enhanced through the expression of NF-κB p65. Treatment with PDTC, TPCK or Bay117082 effectively antagonized LPS-induced IL-8 protein release. Moreover, both the promoter activity and the LPS-induced release of IL-8 were diminished upon the administration of U0126 and SB203580, but not SP600125. Moreover, the exposure to LPS activated ERK1/2 and p38 MAPK phosphorylation in cells.

CONCLUSIONS

This study reports the LPS-mediated transcriptional and post-translational up-regulation of IL-8, which is a process that also involves TLR4, MyD88, NF-κB and MAPK.

Progesterone interactions with the cervix: translational implications for term and preterm birth

The uterine cervix plays a vital role in maintaining pregnancy and an equally important role in allowing parturition to occur. Progesterone, either endogenously produced or supplied exogenously, supports the function of the cervix in sustaining intrauterine pregnancy, and the withdrawal of progesterone, either through natural processes or pharmacologic intervention, leads to delivery which underscores the importance of the progesterone's biological activities manifest in normal gestation and pregnancy that ends prematurely. Research crossing many scientific disciplines has demonstrated that progesterone is a pleotropic compound that affects the cervix through cytoplasmic and membrane receptors with profound effects on cellular and molecular functions that influence inflammatory cascades and extracellular matrix, both of which have consequences for parturition. Beyond the local cell and molecular biology of progesterone, it has systemic effects of relevance to pregnancy as well. This paper examines the biology of the cervix from its gross to cellular structure and biological activities of its cell and molecular processes that may be affected by progesterone. The implications of these processes for preterm birth are explored, and direction of current research is in relation to translational medicine implications for diagnostic, prognostic, and therapeutic approaches to threatened preterm birth.