Effect of TLR3 and TLR7 activation in uterine NK cells from non-obese diabetic (NOD) mice

Progesterone-mediated immunoregulation of cytokine signaling by miRNA-133a and 101-3p in Chlamydia trachomatis-associated recurrent spontaneous abortion

miRNAs regulate the expression of various genes involved in cellular and metabolic pathways in pregnancy related complications including recurrent spontaneous abortion (RSA). Modulation of progesterone and associated pro-inflammatory cytokines by miRNAs in Chlamydia trachomatis-associated RSA is still under investigation. Present study aimed to evaluate the expression/correlation of serum-circulating miRNAs-133a, 101-3p, 320b, 146b-5p, 24, 559, progesterone and few cytokines in C. trachomatis-positive spontaneous aborters. Non-heparinized blood and urine was collected from 120 patients with history of RSA (Group I) and 120 patients with ≥ 2 successful deliveries (Group II) attending Department of Obstetrics and Gynecology, Safdarjung hospital, New Delhi, India. C. trachomatis detection was performed by PCR and chlamydial load by real time PCR. Progesterone concentration was estimated by ELISA. miRNAs and cytokine expression was studied by quantitative real-time PCR and correlated with progesterone expression. Twenty six patients were found to be positive for C. trachomatis. miRNAs- 133a, 101-3p showed maximum upregulation in infected versus control patients. miRNA expression showed positive correlation with chlamydial load. Progesterone concentration showed significant decrease while cytokines (IL-6, IFN-γ, TNF-α) were significantly upregulated in C. trachomatis-positive patients. Positive correlation was observed between expression of miRNAs-133a and 101-3p and cytokines while negative correlation was observed with progesterone in infected RSA patients. Correlation between progesterone and cytokines was found to be significantly negative in infected RSA patients. Although further validation is required, the study concludes that miR-133a and 101-3p are of clinical importance and have a role in immunoregulation of progesterone and cytokines in infection associated RSA.

Prevention of intrauterine fetal growth restriction by administrating C1q/TNF-related protein 6, a specific inhibitor of the alternative complement pathway

PURPOSE

The latest treatments do not sufficiently prevent miscarriage and fetal growth restriction (FGR) in pregnant women. Here, we assessed the effects of a human protein, CTRP6, that specifically inhibits the activation of the alternative complement pathway on miscarriage, fetal and placental development.

METHODS

Pregnant CBA/J mice mated with DBA/2 male mice as a model of spontaneous abortion and FGR were randomly divided into the control and CTRP6 groups. In the CTRP6 group, the mice were intravenously administered CTRP6 on days 4.5 and 6.5 post-conception (dpc). The abortion rate and fetal and placental weights on 14.5 dpc were examined. Remodeling of the spiral artery was also assessed.

RESULTS

The abortion rate in the CTRP6 group (13%) was reduced compared to the control group (21%), but there was no statistical difference. The placental and fetal weights in the CTRP6 group were also heavier than those in the control (P < 0.05). Moreover, the thickness of the blood vessel wall in the CTRP6 group was significantly thinner than that in the control (P < 0.05) and comparable to that in the non-abortion model (CBA/J x BALB). The ratio of the inner-per-the-outer diameter of the spiral artery increased more in the CTRP6 group than that in the control (P < 0.05). As well, the Th1/Th2 cytokine ratio was significantly reduced by CTRP6 treatment.

CONCLUSIONS

Taken together, the supplementation with a protein that regulates the alternative complement pathway in vivo improves FGR and promotes spiral artery remodeling in a mouse model of miscarriage and FGR.

Preterm Birth in Women With HIV: The Role of the Placenta

Maternal HIV infection is associated with an increased risk of preterm birth (PTB). However, the mechanisms underlying this increased risk in women with HIV remain poorly understood. In this regard, it is well-established that labor is an inflammatory process and premature activation of the pro-inflammatory signals (associated with labor) can result in preterm labor which can subsequently lead to PTB. HIV infection is known to cause severe immune dysregulation within its host characterized by altered immune profiles, chronic inflammation and eventually, the progressive failure of the immune system. The human placenta comprises different immune cell subsets, some of which play an important role during pregnancy including participating in the inflammatory processes that accompany labor. It is therefore plausible that HIV/antiretroviral therapy (ART)-associated immune dysregulation within the placental microenvironment may underlie the increased risk of PTB reported in women with HIV. Here, we review evidence from studies that point toward the placental origin of spontaneous PTB and discuss possible ways maternal HIV infection and/or ART could increase this risk. We focus on key cellular players in the maternal decidua including natural killer cells, CD4+ T cells including CD4+ regulatory T cells, CD8+ T cells as well as macrophages.

Low-dose aspirin protects unexplained recurrent spontaneous abortion via downregulation of HMGB1 inflammation activation

BACKGROUND

High mobility group box protein 1 (HMGB1) is considered as a kind of sterile inflammatory mediators, which is an overexpression in patients with unexplained recurrent spontaneous abortion (URSA). Specific targeting effect of aspirin on HMGB1 has been revealed. Our previous studies have explored the application of HMGB1 as a therapeutic target of aspirin in URSA disease of mice model and human, but the dynamic process of aspirin downregulating HMGB1 concentration has not been demonstrated.

METHODS

From December 2018 to November 2020, women with URSA (n = 91) and control women (n = 90) with no history of recurrent abortion or adverse pregnancy were included in the Reproductive Medicine Center of the First Affiliated Hospital of Anhui Medical University. ELISA was applied to detect the concentrations of HMGB1 and IFN-γ in the peripheral blood. Thirty-one URSA patients were monitored for low-dose aspirin treatment (2 and 4 weeks), the changes of HMGB1 and IFN-γ concentrations in peripheral blood of URSA patients before and after using aspirin were compared, and pregnancy outcomes after aspirin treatment were followed up.

RESULTS

The levels of HMGB1 in peripheral blood were significantly higher in URSA patients compared with controls, decreasing trends of HMGB1 and IFN-γ concentrations in plasma of URSA patients were observed after treatment with low-dose aspirin continuously, and the expression of HMGB1 was positively correlated with IFN-γ. There were no birth abnormalities in the babies of the URSA patients treated with aspirin.

CONCLUSIONS

High levels of HMGB1 may be one of the pathogenesis of URSA. Low-dose aspirin may provide protective effect on the HMGB1-triggered URSA.

T helper cell immunity in pregnancy and influence on autoimmune disease progression

Pregnancy presents the maternal immune system with a unique immunological challenge since it has to defend against pathogens while tolerating paternal allo-antigens expressed by fetal tissues. T helper (Th) cells play a central role in modulating immune responses and recent advances have defined distinct contributions of various Th cell subsets throughout each phase of human pregnancy, while dysregulation in Th responses show association with multiple obstetrical complications. In addition to localized decidual mechanisms, modulation of Th cell immunity during gestation is mediated largely by oscillations in sex hormone concentrations. Aberrant Th cell responses also underlie several autoimmune disorders while pregnancy-induced changes in the balance of Th cell immunity has been shown to exert favorable outcomes in the progression Th1 and Th17 driven autoimmune conditions only to be followed by post-partal exacerbations in disease.

Analysis of chicken macrophage functions and gene expressions following infectious bronchitis virus M41 infection

Infectious bronchitis virus (IBV) is a pathogenic coronavirus with high morbidity and mortality in chicken breeding. Macrophages with normal biofunctions are essential for host immune responses. In this study, the HD11 chicken macrophage cell line and chicken peripheral blood mononuclear cell-derived macrophages (PBMCs-Mφ) were infected with IBV at multiplicity of infection (MOI) of 10. The dynamic changes of their biofunctions, including cell viability, pathogen elimination function, phagocytic ability, and gene expressions of related proteins/mediators in innate and acquired immunity, inflammation, autophagy and apoptosis were analyzed. Results showed that IBV infection decreased chicken macrophage viability and phagocytic ability, and increased pathogen elimination function. Moreover, IBV augmented the gene expressions of most related proteins in macrophages involved in multiple host bioprocesses, and the dynamic changes of gene expressions had a close relationship with virus replication. Among them, MHCII, Fc receptor, TLR3, IFN-α, CCL4, MIF, IL-1β, IL-6, and iNOS showed significantly higher expressions in IBV-infected cells. However, TLR7, MyD88, MDA5, IFN-γ, MHCII, Fc receptor, MARCO, CD36, MIF, XCL1, CXCL12, TNF-α, iNOS, and IL-10 showed early decreased expressions. Overall, chicken macrophages play an important role in host innate and acquired immune responses to resist IBV infection, despite early damage or suppression. Moreover, the IBV-induced autophagy and apoptosis might participate in the virus-host cell interaction which is attributed to the biological process.

T Helper (Th) Cell Profiles in Pregnancy and Recurrent Pregnancy Losses: Th1/Th2/Th9/Th17/Th22/Tfh Cells

During pregnancy, various immune effectors and molecules participating in the immune-microenvironment establish specific maternal tolerance toward the semi-allogeneic fetus. Activated maternal immune effectors by the trophoblast antigens, such as T helper (Th), T cytotoxic (Tc), T regulatory (Treg), and B cells, are involved in the regulation of adaptive immunity. Recognition of active signal through the T cell receptors stimulate the differentiation of naive CD3⁺CD4⁺ T cells into specific T cell subsets, such as Th1, Th2, Th9, Th17, Th22, and follicular Th cells (Tfh). Each of these subsets has a significant and distinct role in human pregnancy. Th1 immunity, characterized by immune-inflammatory responses, becomes dominant during the peri-implantation period, and the “controlled” Th1 immunity benefits the invading trophoblasts rather than harm. Quickly after the placental implantation, the early inflammatory Th1 immunity is shifted to the Th2 anti-inflammatory immune responses. The predominant Th2 immunity, which overrules the Th1 immunity at the placental implantation site, protects a fetus by balancing Th1 immunity and accommodate fetal and placental development. Moreover, Treg and Th9 cells regulate local inflammatory immune responses, potentially detrimental to the fetus. Th17 cells induce protective immunity against extracellular microbes during pregnancy. However, excessive Th17 immunity may induce uncontrolled neutrophil infiltration at the maternal-fetal interface. Other Th cell subsets such as Tfh cells, also contribute to pregnancy by setting up favorable humoral immunity during pregnancy. However, dysregulation of Th cell immunity during pregnancy may result in obstetrical complications, such as recurrent pregnancy losses (RPL) and preeclampsia (PE). With this review, we intend to deliver a comprehensive overview of CD4⁺ Th cell subsets, including Th1, Th2, Th9, Th17, Th22, and Tfh cells, in human pregnancy by reviewing their roles in normal and pathological pregnancies.

CaMK4 promotes abortion-related Th17 cell imbalance by activating AKT/mTOR signaling pathway

PROBLEM

The balance of the immune microenvironment along the maternal-fetal interface is closely related to pregnancy outcomes, with excessive inflammatory reactions leading to the occurrence of pathological pregnancy outcomes such as abortion. CaMK4 has been reported to play a significant role in autoimmune diseases through the regulation of Th17 cells. However, whether CaMK4 is associated with spontaneous abortion or the immune microenvironment along the maternal-fetal interface remains unclear.

METHODS OF STUDY

In this study, we constructed normal pregnancy and LPS-induced abortion models in mice, and a CaMK4 inhibitor called KN-93 was administered to investigate the changes in and mechanisms of the immune response. The expression of CaMK4 was evaluated in the uteroplacental complex and spleen. Furthermore, the infiltration and function of Th17 cells were estimated in peripheral tissues and the uteroplacental complex.

RESULTS

The expression of CaMK4 in the uteroplacental complex and spleen was significantly higher in the LPS-treated group than in the normal pregnancy group. KN-93, the CaMK4 inhibitor, reversed fetal resorption and excessive inflammation. In detail, KN-93 led to reduced infiltration of Th17 cells into peripheral tissues and the uteroplacental complex, and the functions of Th17 cells were inhibited. In addition, CaMK4 promoted the AKT/mTOR signaling pathway, which is one of the mechanisms that regulate the immune microenvironment.

CONCLUSION

CaMK4 is a critical regulator that promotes the expansion of Th17 cells and enhances their functions through the AKT/mTOR signaling pathway. The inhibition of CaMK4 can reverse the immune imbalance along the maternal-fetal interface and improve pregnancy outcomes.

Does tumour necrosis factor alpha-induced cyclooxygenase-2 expression lead to spontaneous abortion in Chlamydia trachomatis-infected women

Cytokines might be involved in spontaneous abortion by triggering inflammatory mediators (Cyclooxygenases (Cox)) leading to spontaneous abortion in Chlamydia trachomatis (Ct)-infected women. Study aimed to quantitate the expression of pro-inflammatory cytokines (TNF-α, IFN-γ, IL-8) and Cox-2 in endometrial curettage tissue (ECT) of Spontaneous Aborters (SA). SA (n = 135) and 120 age-matched controls were enrolled from SJH, New Delhi, India. PCR was performed for detection of Ct MOMP gene (537 bp) in ECT. mRNA expression of pro-inflammatory cytokines and Cox-2 was assessed by real-time qPCR. Data was statistically evaluated. 14.8% SA were diagnosed as Ct-positive. Elevated expression of TNF-α, IFN-γ, IL-8 and Cox-2 was observed in Ct-infected SA. Ct-positive recurrent aborters showed significantly higher cytokine expression. Significant positive correlation was found between expression of Cox-2 and TNF-α in infected SA. Data suggested an increased expression of Th-1 cytokines, particularly TNF-α that induced Cox-2 expression in ECT, leading to spontaneous abortion in Ct-infected pregnant women.

Dynamic Function and Composition Changes of Immune Cells During Normal and Pathological Pregnancy at the Maternal-Fetal Interface

A successful pregnancy requires a fine-tuned and highly regulated balance between immune activation and embryonic antigen tolerance. Since the fetus is semi-allogeneic, the maternal immune system should exert tolerant to the fetus while maintaining the defense against infection. The maternal-fetal interface consists of different immune cells, such as decidual natural killer (dNK) cells, macrophages, T cells, dendritic cells, B cells, and NKT cells. The interaction between immune cells, decidual stromal cells, and trophoblasts constitute a vast network of cellular connections. A cellular immunological imbalance may lead to adverse pregnancy outcomes, such as recurrent spontaneous abortion, pre-eclampsia, pre-term birth, intrauterine growth restriction, and infection. Dynamic changes in immune cells at the maternal-fetal interface have not been clearly stated. While many studies have described changes in the proportions of immune cells in the normal maternal-fetus interface during early pregnancy, few studies have assessed the immune cell changes in mid and late pregnancy. Research on pathological pregnancy has provided clues about these dynamic changes, but a deeper understanding of these changes is necessary. This review summarizes information from previous studies, which may lay the foundation for the diagnosis of pathological pregnancy and put forward new ideas for future studies.

Low expression of miR-186-5p regulates cell apoptosis by targeting toll-like receptor 3 in high glucose-induced cardiomyocytes

To investigate the effect and mechanism of microRNA-186-5p (miR-186-5p) on the apoptosis in high glucose (HG)-treated cardiomyocytes. Diabetic cardiomyopathy model was established in cardiomyocytes by stimulating with HG. The expressions of miR-186-5p and toll-like receptor 3 (TLR3) were detected by quantitative polymerase chain reaction or Western blot analysis, respectively. Apoptosis was detected in HG-treated cardiomyocytes by flow cytometry and Western blot analysis. The interaction between miR-186-5p and TLR3 was explored by bioinformatics analysis and luciferase activity assay. Results showed that miR-186-5p expression was downregulated in HG-treated cardiomyocytes and its overexpression reversed HG-induced apoptosis and cleaved caspase-3 protein expression. Moreover, TLR3 was indicated as a target of miR-186-5p and regulated by miR-186-5p. Knockdown of TLR3 suppressed HG-induced apoptosis and cleaved caspase-3 protein expression. Besides, restoration of TLR3 ablated the effect of miR-186-5p on cell apoptosis. Collectively, miR-186-5p attenuated HG-induced apoptosis by regulating TLR3 in cardiomyocytes, providing novel biomarker for treatment of diabetic cardiomyopathy.

TLR3 Modulates the Response of NK Cells against Schistosoma japonicum

Natural killer (NK) cells are classic innate immune cells that play roles in many types of infectious diseases. NK cells possess many kinds of TLRs that allow them to sense and respond to invading pathogens. Our previous study found that NK cells could modulate the immune response induced by Schistosoma japonicum (S. japonicum) in C57BL/6 mice. In the present study, the role of TLRs in the progress of S. japonicum infection was investigated. Results showed that the expression of TLR3 on NK cells increased significantly after S. japonicum infection by using RT-PCR and FACS (P < 0.05). TLR3 agonist (Poly I:C) increased IFN-γ and IL-4 levels in the supernatant of cultured splenocytes and induced a higher percentage of IFN-γ- and IL-4-secreting NK cells from infected mouse splenocytes (P < 0.05). Not only the percentages of MHC II-, CD69-, and NKG2A/C/E-expressing cells but also the percentages of IL-4-, IL-5-, and IL-17-producing cells in TLR3⁺ NK cells increased significantly after infection (P < 0.05). Moreover, the expression of NKG2A/C/E, NKG2D, MHC II, and CD69 on the surface of splenic NK cells was changed in S. japonicum-infected TLR3^-/- (TLR3 KO mice, P < 0.05); the abilities of NK cells in IL-4, IL-5, and IL-17 secretion were decreased too (P < 0.05). These results indicate that TLR3 is the primary molecule which modulates the activation and function of NK cells during the course of S. japonicum infection in C57BL/6 mice.

Expression of C-type lectin receptors and Toll-like receptors in decidua of patients with unexplained recurrent spontaneous abortion

In the present study, the mechanisms underlying the pathogenesis of unexplained recurrent spontaneous abortion (URSA) were explored. The protein and mRNA expression of two C-type lectin-like receptors (CLRs), namely dendritic cell-specific intercellular adhesion molecule-3-grabbing non-integrin (DC-SIGN) and mannose receptor (MR), and two Toll-like receptors (TLRs), namely TLR2 and TLR4, in the decidua and dendritic cells (DCs) was compared between URSA patients and normal controls. URSA patients had significantly lower protein and mRNA expression of DC-SIGN and significantly higher expression of TLR2 and TLR4 in decidual tissues compared with normal controls. In addition, URSA patients had significantly higher levels of the T helper (Th) 1 cytokines interleukin (IL)-2 and interferon-γ, and significantly lower levels of the Th2 cytokines IL-10 and transforming growth factor β1 in decidual tissues compared with the control group. The TLR2 agonist synthetic triacylated lipoprotein (Pam3CSK4) and the TLR4 agonist lipopolysaccharide were used to demonstrate that TLR2 and TLR4 modulate Th1/Th2 cytokine imbalance in DC–T cell cocultures. The results suggest that the balance between CLRs and TLRs was tilted towards a TLR-dominant response in URSA patients, which may disrupt maternal–fetal immune tolerance, resulting in spontaneous abortion.

Transcriptomic Insights into the Response of Placenta and Decidua Basalis to the CpG Oligodeoxynucleotide Stimulation in Non-Obese Diabetic Mice and Wild-Type Controls

Intrauterine infection is one of the most frequent causes of miscarriage. CpG oligodeoxynucleotide (CpG ODN) can mimic intrauterine infection. CpG ODN-induced embryo-resorption was observed consistently in the NK-cell deficient non-obese diabetic (NOD) mice but not in the wild-type (WT) mice. To elucidate the molecular mechanisms of differential pregnancy outcomes, differentially expressed genes (DEGs) in the placenta and decidua basalis was revealed by RNA-Seq with CpG ODN or control ODN treatment. Common DEGs in the WT and NOD mice were enriched in antimicrobial/antibacterial humoral responses that may be activated as a primary response to bacterial infection. The susceptibility to CpG ODN-induced embryo-resorption in the NOD mice might mainly be attributed to M1 macrophage polarization and the immunodeficient status, such as the down-regulation in antigen processing and presentation, allograft rejection, and natural killer cell mediated cytotoxicity. In contrast, the WT mice with normal immune systems could activate multiple immune responses and be resistant to CpG ODN-induced embryo-resorption, such as M2 macrophage differentiation and activation regulated by complement component C1q and peroxisome proliferation-activated receptor (PPAR) signaling pathways. Collectively, this study suggests that the immunodeficient status of NOD mice and the macrophage polarization regulated by C1q and PPAR signaling might be the basis for differential pregnancy outcomes between the NOD and WT mice.

Potential effects of interferon regulatory factor 4 in a murine model of polyinosinic-polycytidylic acid-induced embryo resorption

Interferon regulatory factor (IRF) 4 has been reported to modulate Toll-like receptor (TLR) signalling. Polyinosinic-polycytidylic acid (poly(I:C)) can be specifically recognised by TLR3, triggering the innate immune response and subsequently resulting in pregnancy loss. In the present study, poly(I:C) was administered to mice with or without TLR3 blockade. Chemokine (C-X-C motif) receptor 4 (CXCR4) expression was measured with or without chemokine (C-X-C motif) ligand 12 (CXCL12) inhibition. In cultured murine splenic mononuclear cells, IRF4 was knocked down by a specific short interference (si) RNA. IRF4 mRNA and protein levels and T helper (Th) 17 cell frequencies in the poly(I:C)-treated group were significantly higher than in the phosphate-buffered saline (PBS)-treated control group, and were correlated with a significantly higher embryo resorption rate. Interleukin (IL)-17A and IL-21 levels were markedly lower in the IRF4 siRNA-treated group than in the non-specific siRNA- or vehicle control-treated groups. The CXCR4+ cell frequency was significantly higher among IRF4+ uterine mononuclear and granular cells (UMGCs) compared with IRF4- cells. Inhibition of CXCL12 significantly abrogated poly(I:C)-induced increases in the frequency of IRF4+CXCR4+ cells in UMGCs. IRF4 might play a critical role in TLR3 signalling, which mediates Th17 cell activation and upregulates the expression of IL-17A and IL-21, which results in pregnancy loss. CXCL12 may modulate IRF4+CXCR4+ cell migration at the fetomaternal interface. TLR3 and IRF4 blockade could potentially prevent spontaneous abortion under certain conditions.

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.

Anakinra and etanercept prevent embryo loss in pregnant nonobese diabetic mice

Bacteria and viruses activate the host innate immune response via Toll-like receptor (TLR)-involved signaling and potentially cause pregnancy failure. TLR7 and TLR9 respond to single-stranded RNA (a viral intermediate) and hypomethylated CpG DNA motifs (specific molecular constituents of bacteria) respectively. In this study, we treated murine RAW264.7 cells with R837, CpG1826, or a combination of the two. RT-PCR was performed to detect cytokines, Tlr7, and Tlr9. WT and nonobese diabetic murine embryo resorption models were established by i.p. injections of TLR7 and TLR9 ligands. Neutralizing antibodies and the IL1β and TNFα inhibitors were used. The specific inhibitors anakinra and etanercept effectively prevented TLR7 and TLR9 ligand-induced embryo loss. Notably, this effect was not observed in decidual NK cell-depleted mice. Our findings suggest that anakinra and etanercept may have potential for preventing TLR7 or TLR9 ligand-induced abortion in the presence of decidual NK cells.

Prevention of CpG-induced pregnancy disruption by adoptive transfer of in vitro-induced regulatory T cells

OBJECTIVE

To elucidate the mechanism by which embryo-resorption and preterm birth were enhanced by pathogenic CpG motif and to develop a counter strategy for normal pregnancy outcome.

METHODS

This is an animal model-based study. In pregnant nonobese diabetic (NOD) mice and wild-type (WT) mice in the same strain background, an infection was mimicked by toll-like receptor 9 (TLR9) activation through CpG1826-injection. In vivo inactivation of IL-10 was performed to enhance pregnancy loss. Regulatory T cells induced by FTY720 in vitro from splenic CD4+CD25-Foxp3- cells (iTreg cells) were transferred to improve pregnancy outcomes in NOD mice.

RESULTS

Embryo-resorption and preterm birth were readily induced by CpG1826 in NOD mice, but not in WT mice. However, inactivation of IL-10 using neutralizing antibody injections enhanced pregnancy loss in WT mice exposed to CpG, while adoptive transfer of iTreg cells increased decidual Foxp3+ Treg cells and IL-10+ cell number and rescued pregnancy.

CONCLUSIONS

NOD mice are prone to abortion and preterm birth. This can be attributed to lacking Treg cells and insufficient IL-10 expression. Adoptive transfer of iTreg cells can rescue CpG-mediated pregnancy failure.

Differential effects of the CpG-Toll-like receptor 9 axis on pregnancy outcome in nonobese diabetic mice and wild-type controls

OBJECTIVE

To elucidate the relationship between CpG-induced activation of innate immunity and pregnancy outcome.

DESIGN

An animal model-based study.

SETTING

Academic.

ANIMAL(S)

Pregnant nonobese diabetic (NOD) mice were compared with nonimmunodeficient mice.

INTERVENTION(S)

We mimic toll-like receptor 9 (TLR9) activation using CpG ODN administration in pregnant wild-type (WT) and natural killer (NK) cell-deficient NOD mice.

MAIN OUTCOME MEASURE(S)

Evaluation of fetal resorption and preterm birth in pregnant mice; flow-cytometric analysis and ELISA detection.

RESULT(S)

CpG-induced fetal resorption or preterm birth was observed steadily only in NOD mice but not in WT mice. Concurrently, CpG treatment triggered amplification of uterine macrophages and neutrophils. Moreover, CpG induced a substantial increase of serum mouse keratinocyte-derived cytokine (mKC) and tumor necrosis factor-α (TNF-α) that were produced by uterine CD11b(+)F4/80(+) cells but not by NK or CD11b(+)Gr-1(+) cells. In addition, depletion of F4/80(+) cells abrogated a CpG-induced increase in TNF-α production and improved pregnancy outcomes in NOD mice treated with CpG.

CONCLUSION(S)

These results provide evidence that CpG-driven innate immune activation may lead to activation and amplification of macrophages followed by their migration to fetomaternal microenvironment, up-regulated TNF-α production, and consequent adverse pregnancy outcomes.

Effect of hochuekkito on alveolar macrophage inflammatory responses in hyperglycemic mice

Diabetes mellitus reduces immunological activity and increases susceptibility to various infections. Hochuekkito (TJ-41) has been reported to improve the weakened physical condition of various chronic diseases. BALB/c mice were divided into three groups; groups A and B were fed a standard diet, and group C, a TJ-41 diet. Two weeks after starting these diets, hyperglycemia was induced in groups B and C by injection with streptozotocin. Two weeks later, bronchoalveolar lavage was performed. Toll-like receptor (TLR) ligands (TLR2: peptidoglycan, PGN; TLR4: lipopolysaccharide, LPS; TLR5: flagellin, FLG) were used to stimulate alveolar macrophages (AMs), and TNF-α production was measured. Under hyperglycemic conditions and PGN or FLG stimulation, TNF-α production from AMs was significantly reduced in group B compared with group A. However, treatment with TJ-41 (group C) significantly improved the impaired production of TNF-α. These results suggest that, under hyperglycemic conditions, TJ-41 can improve the inflammatory responses of AMs with stimulation of TLR ligands.

Viral ssRNA induces first trimester trophoblast apoptosis through an inflammatory mechanism

PROBLEM

Infection during pregnancy represents a significant cause of mobility and mortality. While viruses pose a major threat, little is known about their effect on early pregnancy, or the mechanisms involved. The objective of this study was to characterize the trophoblast response following exposure to viral ssRNA.

METHOD OF STUDY

First trimester trophoblast cells were treated with or without viral ssRNA. Cytokine production was measured using multiplex analysis and ELISA. Apoptosis was determined using Hoechst staining, cell viability, and caspase activity assays.

RESULTS

Treatment of trophoblasts with viral ssRNA increased their secretion of IL-8, IL-6, and IFNbeta. However, the ssRNA also induced trophoblast apoptosis. To test whether the viral ssRNA-induced inflammatory response was responsible for this induction of apoptosis, conditioned media (CM) from trophoblasts were added to a fresh culture of cells. The CM from viral ssRNA-treated induced higher levels of trophoblast apoptosis than the control CM. Moreover, recombinant IFNbeta induced trophoblast apoptosis.

CONCLUSION

We demonstrate that viral ssRNA induces a pro-inflammatory and type I interferon response in the trophoblast and this inflammatory process may indirectly induce trophoblast apoptosis. These results provide a novel mechanism by which certain viral infections might compromise placental integrity and function, and therefore, pregnancy outcome.

Th1/Th2/Th17 and regulatory T-cell paradigm in pregnancy

T-helper (Th) cells play a central role in modulating immune responses. The Th1/Th2 paradigm has now developed into the new Th1/Th2/Th17 paradigm. In addition to effector cells, Th cells are regulated by regulatory T (Treg) cells. Their capacity to produce cytokines is suppressed by immunoregulatory cytokines such as transforming growth factor (TGF)-beta and interleukin (IL)-10 or by cell-to-cell interaction. Here, we will review the immunological environment in normal pregnancy and complicated pregnancy, such as implantation failure, abortion, preterm labor, and preeclampsia from the viewpoint of the new Th1/Th2/Th17 and Treg paradigms.

Toll-like receptor signaling in uterine natural killer cells--role in embryonic loss

Embryonic development is a complex process that is regulated by many cell types and signaling pathways. This review focuses on the role of NK cells and regulatory T-cells (Treg cells) in embryonic loss. Approximately 70% of uterine leukocytes until the time of mid-gestation are found to be CD16(-)CD56(bright) NK cells. This subset of NK cells, along with Treg cells, has been shown to regulate fetal development. We recently found a population of NK cells in the pregnant mouse uterus with a unique CD3(-)CD49b(+)CD25(+)Foxp3(+) phenotype. This review summarizes the studies indicating critical roles for expression of IL-10 by CD3(-)CD49b(+)CD25(+)Foxp3(+) cells and CXCR4 expression on CD16(-)CD56(bright) NK cells in preventing embryonic loss. In addition, the roles of toll-like receptors (TLRs) and CXCR4 in NK cell migration and functional modulation are discussed.