Human cytomegalovirus-induces cytokine changes in the placenta with implications for adverse pregnancy outcomes

Human Cytomegalovirus Dysregulates Cellular Dual-Specificity Tyrosine Phosphorylation-Regulated Kinases and Sonic Hedgehog Pathway Proteins in Neural Astrocyte and Placental Models

Human cytomegalovirus (CMV) infection is the leading non-genetic cause of congenital malformation in developed countries, causing significant fetal injury, and in some cases fetal death. The pathogenetic mechanisms through which this host-specific virus infects then damages both the placenta and the fetal brain are currently ill-defined. We investigated the CMV modulation of key signaling pathway proteins for these organs including dual-specificity tyrosine phosphorylation-regulated kinases (DYRK) and Sonic Hedgehog (SHH) pathway proteins using human first trimester placental trophoblast (TEV-1) cells, primary human astrocyte (NHA) brain cells, and CMV-infected human placental tissue. Immunofluorescence demonstrated the accumulation and re-localization of SHH proteins in CMV-infected TEV-1 cells with Gli2, Ulk3, and Shh re-localizing to the CMV cytoplasmic virion assembly complex (VAC). In CMV-infected NHA cells, DYRK1A re-localized to the VAC and DYRK1B re-localized to the CMV nuclear replication compartments, and the SHH proteins re-localized with a similar pattern as was observed in TEV-1 cells. Western blot analysis in CMV-infected TEV-1 cells showed the upregulated expression of Rb, Ulk3, and Shh, but not Gli2. In CMV-infected NHA cells, there was an upregulation of DYRK1A, DYRK1B, Gli2, Rb, Ulk3, and Shh. These in vitro monoculture findings are consistent with patterns of protein upregulation and re-localization observed in naturally infected placental tissue and CMV-infected ex vivo placental explant histocultures. This study reveals CMV-induced changes in proteins critical for fetal development, and identifies new potential targets for CMV therapeutic development.

The Association between Prenatal Nicotine Exposure and Offspring's Hearing Impairment

OBJECTIVES

 The objective of this study is to evaluate whether there is an association between in-utero exposure to nicotine and subsequent hearing dysfunction.

MATERIALS AND METHODS

 Secondary analysis of a multicenter randomized trial to prevent congenital cytomegalovirus (CMV) infection among gravidas with primary CMV infection was conducted. Monthly intravenous immunoglobulin hyperimmune globulin therapy did not influence the rate of congenital CMV. Dyads with missing urine, fetal or neonatal demise, infants diagnosed with a major congenital anomaly, congenital CMV infection, or with evidence of middle ear dysfunction were excluded. The primary outcome was neonatal hearing impairment in one or more ears defined as abnormal distortion product otoacoustic emissions (DPOAEs; 1 to 8 kHz) that were measured within 42 days of birth. DPOAEs were interpreted using optimized frequency-specific level criteria. Cotinine was measured via enzyme-linked immunosorbent assay kits in maternal urine collected at enrollment and in the third trimester (mean gestational age 16.0 and 36.7 weeks, respectively). Blinded personnel ran samples in duplicates. Maternal urine cotinine >5 ng/mL at either time point was defined as in-utero exposure to nicotine. Multivariable logistic regression included variables associated with the primary outcome and with the exposure (p < 0.05) in univariate analysis.

RESULTS

 Of 399 enrolled patients in the original trial, 150 were included in this analysis, of whom 46 (31%) were exposed to nicotine. The primary outcome occurred in 18 (12%) newborns and was higher in nicotine-exposed infants compared with those nonexposed (15.2 vs. 10.6%, odds ratio [OR] 1.52, 95% confidence interval [CI] 0.55-4.20), but the difference was not significantly different (adjusted odds ratio [aOR] = 1.0, 95% CI 0.30-3.31). This association was similar when exposure was stratified as heavy (>100 ng/mL, aOR 0.72, 95% CI 0.15-3.51) or mild (5-100 ng/mL, aOR 1.28, 95% CI 0.33-4.95). There was no association between nicotine exposure and frequency-specific DPOAE amplitude.

CONCLUSION

 In a cohort of parturients with primary CMV infection, nicotine exposure was not associated with offspring hearing dysfunction assessed with DPOAEs.

KEY POINTS

· Nicotine exposure was quantified from maternal urine.. · Nicotine exposure was identified in 30% of the cohort.. · Exposure was not associated with offspring hearing dysfunction..

Cytomegalovirus infection during pregnancy

Cytomegalovirus (CMV) infection during pregnancy is a global silent problem. Additionally, it is the leading cause of congenital infections, non-genetic sensorineural hearing loss, and neurodevelopmental delays in infants. However, this has barely been recognized globally. This condition lacks adequate attention, which is further emphasized by the lack of awareness among healthcare workers and the general population. The impact of CMV infection is often overlooked because of the asymptomatic nature of its presentation in infected pregnant women and newborns, difficulty in diagnosis, and the perception that infants born to women with pre-existing antibodies against CMV have normal neonatal outcomes. This article highlights the latest information on the epidemiology, transmission, clinical manifestations, and development of CMV infection and its management. We reviewed the pathophysiology and clinical manifestations of CMV infection in pregnant women, diagnostic methods, including screening and prognostic markers, and updates in treatment modalities. Current advancements in research on vaccination and hyperimmunoglobulins with worldwide treatment protocols are highlighted.

Counting the Toll of Inflammation on Schizophrenia-A Potential Role for Toll-like Receptors

Toll-like receptors (TLRs) are a family of pattern recognition receptors (PRRs) that are ubiquitously expressed in the human body. They protect the brain and central nervous system from self and foreign antigens/pathogens. The immune response elicited by these receptors culminates in the release of cytokines, chemokines, and interferons causing an inflammatory response, which can be both beneficial and harmful to neurodevelopment. In addition, the detrimental effects of TLR activation have been implicated in multiple neurodegenerative diseases such as Alzheimer's, multiple sclerosis, etc. Many studies also support the theory that cytokine imbalance may be involved in schizophrenia, and a vast amount of literature showcases the deleterious effects of this imbalance on cognitive performance in the human population. In this review, we examine the current literature on TLRs, their potential role in the pathogenesis of schizophrenia, factors affecting TLR activity that contribute towards the risk of schizophrenia, and lastly, the role of TLRs and their impact on cognitive performance in schizophrenia.

Genetic and Functional Characterization of Congenital HCMV Clinical Strains in Ex Vivo First Trimester Placental Model

Human cytomegalovirus (HCMV) is the leading cause of congenital viral infection, leading to a variety of symptoms in the unborn child that range from asymptomatic to death in utero. Our objective was to better understand the mechanisms of placental infection by HCMV clinical strains, particularly during the first trimester of pregnancy. We thus characterized and compared the replication kinetics of various HCMV clinical strains and laboratory strains by measuring viral loads in an ex vivo model of first trimester villi and decidua, and used NGS and PCA analysis to analyze the genes involved in cell tropism and virulence factors. We observed that first trimester villi and decidua are similarly permissive to laboratory and symptomatic strains, and that asymptomatic strains poorly replicate in decidua tissue. PCA analysis allowed us to segregate our clinical strains based on their clinical characteristics, suggesting a link between gene mutations and symptoms. All these results bring forth elements that can help better understand the mechanisms that induce the appearance of symptoms or in the congenitally infected newborn.

Prevention of Congenital Cytomegalovirus Infection: Review and Case Series of Valaciclovir versus Hyperimmune Globulin Therapy

Cytomegalovirus (CMV) is the most common cause of congenital infections in developed countries because is capable of infecting the fetus after both primary and recurrent maternal infection, and because the virus may be spread for years through infected children. Moreover, CMV is the most serious congenital infection associated with severe neurological and sensorineural sequelae, which can occur at birth or develop later on. Hygienic measures can prevent CMV transmission, which mainly involve contact with children under 3 years of age and attending a nursery or daycare. In animal and human pregnancies, many observational and controlled studies have shown that CMV-specific hyperimmune globulin (HIG) is safe and can significantly decrease maternal-fetal transmission of CMV infection and, mostly, the occurrence of CMV disease. Recently, valaciclovir at the dosage of 8 g/day was also reported to be capable of decreasing the rates of congenital infection and disease. However, comparing the results of our two recent case series, the infants born to women treated with HIG showed significantly lower rates of CMV DNA positivity in urine (9.7% vs. 75.0%; p < 0.0001) and abnormalities after follow-up (0.0% vs. 41.7%; p < 0.0001). The implementation of CMV screening would enable primary prevention via hygiene counseling, improve the understanding and awareness of congenital CMV infection, and increase the knowledge of the potential efficacy of preventive or therapeutic HIG or antiviral administration.

The Association of Cytomegalovirus IgM and Allostatic Load

Background: Cytomegalovirus (CMV) is a deoxyribonucleic acid virus that affects a significant proportion of the worldwide population; after primary infection, it goes into a latent state and can be reactivated, primarily after a reduction in host immune defenses. Methods: This study evaluated the association of acute cytomegalovirus infection (CMV IgM) and Allostatic Load (AL) by sociodemographic factors using data from the National Health and Nutrition Examination Survey (NHANES) 2001–2004 among participants (aged 20–49 years). CMV infection was determined by the level of CMV IgM antibody in serum samples. AL was assessed as a combination of 10 biomarkers from the cardiovascular, inflammatory, and metabolic systems. The evaluation of the association between CMV infection and AL included descriptive statistics and logistic regression models, which were adjusted for demographic and behavioral covariates. Results: AL was more elevated among those who were older, male, those with lower education, those performing limited physical activity, and smokers. CMV was more elevated in females than males among those who consumed alcohol and cigarette smokers. In Pearson’s correlation analysis, there was a slight positive correlation between CMV IgM and AL, with triglycerides and Body Mass Index (BMI) the most strongly correlated with AL. Binary logistic regression showed no significant relationship between high AL and positive CMV IgM but did show a significant relationship between high AL and age (OR = 1.0592, 95% CI 1.0215–1.0983, p = 0.00715). The findings of this study provide insight into the relationship between CMV and AL and provide awareness of factors that affect their relationship.

Gestational Antibodies to C. pneumoniae, H. pylori and CMV in Women with Preeclampsia and in Matched Controls

OBJECTIVES

Some research has suggested a possible role for past infection in the development of preeclampsia. The objective of this study was to explore the role of Helicobacter pylori, cytomegalovirus, and Chlamydophila pneumoniae in the development of preeclampsia in a prospective pregnancy sample.

METHODS

We conducted a nested case-control study in The Archive for Child Health (ARCH), a pregnancy cohort of 867 unselected women enrolled at the first prenatal visit with archived blood and urine in pregnancy. We matched 21 cases of preeclampsia to 52 unaffected controls on maternal age (±4 years), race, parity, and gestational age at blood draw. Using conditional logistic regression, we examined the association between preeclampsia status and immunoglobulins G (IgG) tested by indirect ELISA to each of the three microorganisms, adjusting for potential confounders.

RESULTS

No significant difference was found between cases and controls. The unadjusted odds ratio was 1.5 (95%CI: 0.2-9.1), 0.6 (95%CI: 0.2-1.9), and 1.9 (95%CI: 0.6-5.6) for H. pylori, cytomegalovirus and C. pneumoniae respectively. After controlling for confounders analysis found increased odds of H. pylori IgG (AOR: 1.9; 95% CI: 0.2-15.3) and C. pneumoniae IgG (AOR: 2.3; 95% CI: 0.6-9.2) for preeclampsia, albeit being not significant. Conversely, cytomegalovirus IgG had lower odds for preeclampsia (AOR: 0.4; 95% CI: 0.1-1.7).

CONCLUSIONS

Past infection with H. pylori, and C. pneumoniae in early pregnancy showed a higher risk of preeclampsia, but the findings failed to achieve statistical significance. Cytomegalovirus was not associated with preeclampsia in these data. These preliminary findings encourage future research in populations with high prevalence of these infections.

Potential of Anti-CMV Immunoglobulin Cytotect CP® In Vitro and Ex Vivo in a First-Trimester Placenta Model

Background: Congenital CMV infection is the leading cause of neonatal neurological deficit. We herein studied in vitro and ex vivo the potential of the hyperimmune globulin Cytotect CP^® (Biotest, Germany) for congenital infection prevention and treatment. Methods: In vitro neutralization assays were conducted in fibroblasts and retinal epithelial cells on the CMV strains TB40/E and VHL/E to determine the 50% and 90% neutralizing doses (ND50 and ND90). The toxicity was assessed by measuring LDH release. Ex vivo assays were conducted in first-trimester villi explants with the TB40/E strain, namely, neutralization assays, the prevention of villi infection, and the inhibition of viral replication in infected villi. Viability was assessed by β-HCG quantification in supernatants. Results: The in vitro neutralization tests showed that Cytotect CP^®® inhibits the development of infection foci (DN50: 0.011–0.014 U/mL for VHL/E and 0.032–0.033 U/mL for TB40E) without any toxicity. In the ex vivo neutralization assays, the DN50 were 0.011 U/mL on day 7 and 0.093 U/mL on day 14. For the prevention of villi infection, the EC50 was 0.024 U/mL on day 7. Cytotect-CP^® did not inhibit viral growth in infected villi. No impact on villi viability was observed. Conclusions: These results sustained that Cytotect CP^® has the potential to prevent CMV congenital infection.

Constitutive Signaling by the Human Cytomegalovirus G Protein Coupled Receptor Homologs US28 and UL33 Enables Trophoblast Migration In Vitro

Human cytomegalovirus (HCMV) encodes four homologs of G protein coupled receptors (vGPCRs), of which two, designated UL33 and US28, signal constitutively. UL33 and US28 are also conserved with chemokine receptors: US28 binds numerous chemokine classes, including the membrane bound chemokine, fractalkine; whereas UL33 remains an orphan receptor. There is emerging data that UL33 and US28 each contribute to HCMV associated disease, although no studies to date have reported their potential contribution to aberrant placental physiology that has been detected with HCMV congenital infection. We investigated the signaling repertoire of UL33 and US28 and their potential to enable trophoblast mobilization in vitro. Results demonstrate the constitutive activation of CREB by each vGPCR in ACIM-88 and HTR-8SVneo trophoblasts; constitutive NF-kB activation was detected for US28 only. Constitutive signaling by each vGPCR enabled trophoblast migration. For US28, fractalkine exhibited inverse agonist activity and dampened trophoblast migration. UL33 stimulated expression of both p38 mitogen activated (MAP) and Jun N-terminal (JNK) kinases; while p38 MAP kinase stimulated CREB, JNK was inhibitory, suggesting that UL33 dependent CREB activation was regulated by p38/JNK crosstalk. Given that chemokines and their receptors are important for placental development, these data point to the potential of HCMV UL33 and US28 to interfere with trophoblast responses which are important for normal placental development.

Suppression of human trophoblast syncytialization by human cytomegalovirus infection

INTRODUCTION

Placental dysfunction triggers fetal growth restriction in congenital human cytomegalovirus (HCMV) infection. Studies suggest that HCMV infection interferes with the differentiation of human trophoblasts. However, the underlying mechanisms have not been clarified. This study investigated the impact of HCMV infection on gene transcriptomes in cytotrophoblasts (CTBs) associated with placental dysfunction.

METHODS

CTBs were isolated from human term placentas, and spontaneous syncytialization was observed in vitro. The transcriptome profiles were compared between CTB groups with and without HCMV infection by cap analysis gene expression sequencing. The effect of HCMV infection on trophoblast differentiation was evaluated by examining cell fusion status using immunocytochemical staining for desmoplakin and assessing the production of cell differentiation markers, including hCG, PlGF, and soluble Flt-1, using ELISA.

RESULTS

The expression of the genes categorized in the signaling pathways related to the cell cycle was significantly enhanced in CTBs with HCMV infection compared with uninfected CTBs. HCMV infection hindered the alteration of the gene expression profile associated with syncytialization. This suppressive effect under HCMV infection was concurrent with the reduction in hCG and PlGF secretion. Immunostaining for desmoplakin revealed that HCMV infection reduced the cell fusion of cultured CTBs. These findings imply that HCMV infection has a negative impact on syncytialization, which is indispensable for the maintenance of villous function.

DISCUSSION

HCMV infection interferes with gene expression profiles and functional differentiation of trophoblasts. Suppression of syncytialization may be a survival strategy for HCMV to expand infection and could be associated with placental dysfunction.

Review of studies of severe acute respiratory syndrome related coronavirus-2 pathogenesis in human organoid models

Severe acute respiratory syndrome related coronavirus-2 (SARS-CoV-2) is the cause of Covid-19 which was classified as a global pandemic in March 2020. The increasing global health and economic burden of SARS-CoV-2 has necessitated urgent investigations into the pathogenesis of disease and development of therapeutic and vaccination regimens. Human trials of vaccine and antiviral candidates have been undertaken, but basic pathogenetic studies are still required to inform these trials. Gaps in understanding of cellular infection by, and immunity to, SARS-CoV-2 mean additional models are required to assist in improved design of these therapeutics. Human organoids are three-dimensional models that contain multiple cell types and mimic human organs in ex vivo culture conditions. The SARS-CoV-2 virus has been implicated in causing not only respiratory injury but also injury to other organs such as the brain, liver and kidneys. Consequently, a variety of different organoid models have been employed to investigate the pathogenic mechanisms of disease due to SARS-CoV-2. Data on these models have not been systematically assembled. In this review, we highlight key findings from studies that have utilised different human organoid types to investigate the expression of SARS-CoV-2 receptors, permissiveness, immune response, dysregulation of cellular functions, and potential antiviral therapeutics.

Human Cytomegalovirus Infection Changes the Pattern of Surface Markers of Small Extracellular Vesicles Isolated From First Trimester Placental Long-Term Histocultures

Extracellular vesicles (EVs) have increasingly been recognized as key players in a wide variety of physiological and pathological contexts, including during pregnancy. Notably, EVs appear both as possible biomarkers and as mediators involved in the communication of the placenta with the maternal and fetal sides. A better understanding of the physiological and pathological roles of EVs strongly depends on the development of adequate and reliable study models, specifically at the beginning of pregnancy where many adverse pregnancy outcomes have their origin. In this study, we describe the isolation of small EVs from a histoculture model of first trimester placental explants in normal conditions as well as upon infection by human cytomegalovirus. Using bead-based multiplex cytometry and electron microscopy combined with biochemical approaches, we characterized these small EVs and defined their associated markers and ultrastructure. We observed that infection led to changes in the expression level of several surface markers, without affecting the secretion and integrity of small EVs. Our findings lay the foundation for studying the functional role of EVs during early pregnancy, along with the identification of new predictive biomarkers for the severity and outcome of this congenital infection, which are still sorely lacking.

Single Nucleotide Polymorphisms of Interleukins and Toll-like Receptors and Neuroimaging Results in Newborns with Congenital HCMV Infection

Congenital cytomegalovirus infection (cCMV) is the most common intrauterine infection with central nervous system (CNS) involvement. There is limited data on the associations between Single Nucleotide Polymorphisms (SNPs) in genes involving the first-line defense mechanism and the risk of CNS damage during cCMV. We investigated the associations between neuroimaging findings and SNPs in genes encoding the following cytokines and cytokine receptors in 92 infants with cCMV: interleukins (IL1B rs16944, IL12B rs3212227, IL28B rs12979860), C-C motif chemokine ligand 2 (CCL2 rs1024611), dendritic cell-specific intercellular adhesion grabbing non-integrin (DC-SIGN rs735240), Toll-like receptors (TLR2 rs5743708, TLR4 rs4986791, TLR9 rs352140). The SNP of IL1B rs16944 (G/A) was associated with a reduced risk of ventriculomegaly on MRI (OR = 0.46, 95% CI, 0.22-0.95; p = 0.03) and cUS (OR = 0.38, 95% CI, 0.0-0.93; p = 0.034). Infants carrying heterozygous (T/C) genotype at IL28B rs12979860 had an increased risk of cystic lesions on cUS (OR = 3.31, 95% CI, 1.37-8.01; p = 0.0064) and MRI (OR = 4.97, 95% CI, 1.84-13.43; p = 0.001), and an increased risk of ventriculomegaly on MRI (OR = 2.46, 95% CI, 1.03-5.90; p = 0.04). No other associations between genotyped SNPs and neuroimaging results were found. This is the first study demonstrating new associations between SNPs of IL1B and IL28B and abnormal neuroimaging in infants with cCMV.

A placental specific miRNA miR-517a-3p exerts anti-human cytomegalovirus activity

Human cytomegalovirus congenital infection is the leading non-genetic cause of fetal malformation in developed countries. There are currently no safe antivirals for use during pregnancy. Placental trophoblast cells specifically secrete exosomes containing miRNA from the chromosome 19 miRNA cluster (C19MC) which confer viral resistance to recipient cells. We show the highly expressed C19MC miRNA miR-517a-3p inhibits HCMV replication and viral protein expression in both fibroblast and trophoblast cell cultures (71.6% and 50.4% inhibition of HCMV DNA at 7 days post infection respectively; p < 0.05). This naturally occurring molecule has potential for opening-up antiviral therapeutic strategies for pregnancy.

Human Immunodeficiency Virus (HIV) and Human Cytomegalovirus (HCMV) Coinfection of Infant Tonsil Epithelium May Synergistically Promote both HIV-1 and HCMV Spread and Infection

Mother-to-child transmission (MTCT) of human immunodeficiency virus type 1 (HIV-1) and human cytomegalovirus (HCMV) may occur during pregnancy, labor, or breastfeeding. These viruses from amniotic fluid, cervicovaginal secretions, and breast milk may simultaneously interact with oropharyngeal and tonsil epithelia; however, the molecular mechanism of HIV-1 and HCMV cotransmission through the oral mucosa and its role in MTCT are poorly understood. To study the molecular mechanism of HIV-1 and HCMV MTCT via oral epithelium, we established polarized infant tonsil epithelial cells and polarized-oriented ex vivo tonsil tissue explants. Using these models, we showed that cell-free HIV-1 and its proteins gp120 and tat induce the disruption of tonsil epithelial tight junctions and increase paracellular permeability, which facilitates HCMV spread within the tonsil mucosa. Inhibition of HIV-1 gp120-induced upregulation of mitogen-activated protein kinase (MAPK) and NF-κB signaling in tonsil epithelial cells, reduces HCMV infection, indicating that HIV-1-activated MAPK and NF-κB signaling may play a critical role in HCMV infection of tonsil epithelium. HCMV infection of tonsil epithelial cells also leads to the disruption of tight junctions and increases paracellular permeability, facilitating HIV-1 paracellular spread into tonsil mucosa. HCMV-promoted paracellular spread of HIV-1 increases its accessibility to tonsil CD4 T lymphocytes, macrophages, and dendritic cells. HIV-1-enhanced HCMV paracellular spread and infection of epithelial cells subsequently leads to the spread of HCMV to tonsil macrophages and dendritic cells. Our findings revealed that HIV-1- and HCMV-induced disruption of infant tonsil epithelial tight junctions promotes MTCT of these viruses through tonsil mucosal epithelium, and therapeutic intervention for both HIV-1 and HCMV infection may substantially reduce their MTCT. IMPORTANCE Most HIV-1 and HCMV MTCT occurs in infancy, and the cotransmission of these viruses may occur via infant oropharyngeal and tonsil epithelia, which are the first biological barriers for viral pathogens. We have shown that HIV-1 and HCMV disrupt epithelial junctions, reducing the barrier functions of epithelia and thus allowing paracellular penetration of both viruses via mucosal epithelia. Subsequently, HCMV infects epithelial cells, macrophages, and dendritic cells, and HIV-1 infects CD4⁺ lymphocytes, macrophages, and dendritic cells. Infection of these cells in HCMV- and HIV-1-coinfected tonsil tissues is much higher than that by HCMV or HIV-1 infection alone, promoting their MTCT at its initial stages via infant oropharyngeal and tonsil epithelia.

Innate Immune Response to Viral Infections at the Maternal-Fetal Interface in Human Pregnancy

The placenta, the first and largest organ to develop after conception, not only nurtures and promotes the development of the conceptus, but, it also functions as a barrier against invading pathogens. Early phases of pregnancy are associated with expansion of specific subsets of Natural Killer cells (dNK) and macrophages (dMφ) at the maternal uterine mucosa, the basal decidua. In concert with cells of fetal origin, dNK cells, and dMφ orchestrate all steps of placenta and fetus development, and provide the first line of defense to limit vertical transmission. However, some pathogens that infect the mother can overcome this protective barrier and jeopardize the fetus health. In this review, we will discuss how members of the classical TORCH family (Toxoplasma, Other, Rubella, Cytomegalovirus, and Herpes simplex virus) and some emerging viruses (Hepatitis E virus, Zika virus, and SARS-CoV2) can afford access to the placental fortress. We will also discuss how changes in the intrauterine environment as a consequence of maternal immune cell activation contribute to placental diseases and devastating pregnancy outcomes.

Association between single nucleotide polymorphisms and viral load in congenital cytomegalovirus infection

Background

There are limited data on factors that determine viral load (VL) in congenital cytomegalovirus (cCMV) infection. Single nucleotide polymorphisms (SNPs) might influence individual host response to infection. This study aimed to investigate the association between SNPs in genes encoding cytokines or cytokine receptors and VL in newborns with cCMV.

Material and methods

Eight polymorphisms (IL1B rs16944, IL12B rs3212227, IL28B rs12979860, CCL2 rs1024611, DC-SIGN rs735240, TLR2 rs5743708, TLR4 rs4986791 and TLR9 rs352140) were analyzed in study population of 233 newborns, including 92 cCMV-infected newborns (73 symptomatic and 19 asymptomatic) by TaqMan SNP Predesigned Genotyping Assays. The association analysis was performed using SNPStats software and STATISTICA10.

Results

The association between IL12B polymorphism and viruria was observed (p = 0.029). In multiple comparison tests, heterozygous T/G genotype of IL12B was associated with higher viruria than T/T genotype (p = 0.041) in cCMV-infected newborns. In allele analysis, T allele of IL12B was associated with higher viremia (p = 0.037) in symptomatic newborns. We observed higher VL in symptomatic newborns in comparison to asymptomatic (median viremia: 1.7 × 10⁴ copies/mL vs. 2.0 × 10³ copies/mL (p = 0.002), median viruria: 1.0 × 10⁷ copies/mL versus 6.9 × 10⁵ copies/mL (p = 0.001), respectively).

Conclusions

IL12B rs3212227 was associated with VL in cCMV. Symptomatic newborns had significantly higher viremia and viruria. The role of SNPs in pathogenesis of cCMV warrants further investigations.

First trimester mechanisms of gestational sac placental and foetal teratogenicity: a framework for birth cohort studies

BACKGROUND

The function of the gestational sac (GS) and the placenta in the closely related processes of embryogenesis and teratogenicity in the first trimester has been minimally described. The prevailing assumption is that direct teratogenic effects are mediated by the critical extraembryonic organ, the placenta, which either blocks or transfers exposures to the foetus. Placental transfer is a dominant mechanism, but there are other paradigms by which the placenta can mediate teratogenic effects. Knowledge of these paradigms and first trimester human developmental biology can be useful to the epidemiologist in the conduct of biomarker-based studies of both maternal and child health.

OBJECTIVE AND RATIONALE

Our aim is to provide a causal framework for modelling the teratogenic effects of first trimester exposures on child health outcomes mediated by the GS and placenta using biomarker data collected in the first trimester. We initially present first trimester human developmental biology for the sake of informing and strengthening epidemiologic approaches. We then propose analytic approaches of modelling placental mechanisms by way of causal diagrams using classical non-embryolethal teratogens (diethylstilboestrol [DES], folic acid deficiency and cytomegalovirus [CMV]) as illustrative examples. We extend this framework to two chronic exposures of particular current interest, phthalates and maternal adiposity.

SEARCH METHODS

Information on teratogens was identified by a non-systematic, narrative review. For each teratogen, we included papers that answered the five following questions: (i) why were these exposures declared teratogens? (ii) is there a consensus on biologic mechanism? (iii) is there reported evidence of a placental mechanism? (iv) can we construct a theoretical model of a placental mechanism? and (v) can this knowledge inform future work on measurement and modelling of placental-foetal teratogenesis? We prioritized literature specific to human development, the organogenesis window in the first trimester and non-embryolethal mechanisms.

OUTCOMES

As a result of our review of the literature on five exposures considered harmful in the first trimester, we developed four analytic strategies to address first trimester placental mechanisms in birth cohort studies: placental transfer and direct effects on the foetus (DES and maternal adiposity), indirect effects through targeted placental molecular pathways (DES and phthalates), pre-placental effects through disruptions in embryonic and extraembryonic tissue layer differentiation (folic acid deficiency), and multi-step mechanisms that involve maternal, placental and foetal immune function and inflammation (DES and CMV).

WIDER IMPLICATIONS

The significance of this review is to offer a causal approach to classify the large number of potentially harmful exposures in pregnancy when the exposure occurs in the first trimester. Our review will facilitate future research by advancing knowledge of the first trimester mechanisms necessary for researchers to effectively associate environmental exposures with child health outcomes.

Receptors in host pathogen interactions between human cytomegalovirus and the placenta during congenital infection

Cellular receptors in human cytomegalovirus (HCMV) mother to child transmission play an important role in congenital infection. Placental trophoblast cells are a significant cell type in placental development, placental functional processes, and in HCMV transmission. Different cells within the placental floating and chorionic villi present alternate receptors for HCMV cell entry. Syncytiotrophoblasts present neonatal Fc receptors that bind and transport circulating maternal immunoglobulin G across the placental interface which can also be bound to HCMV virions, facilitating viral entry into the placenta and foetal circulation. Cytotrophoblast express HCMV receptors including integrin-α1β1, integrin-αVβ3, epidermal growth factor receptor and platelet-derived growth factor receptor alpha. The latter interacts with HCMV glycoprotein-H, glycoprotein-L and glycoprotein-O (gH/gL/gO) trimers (predominantly in placental fibroblasts) and the gH/gL/pUL128, UL130-UL131A pentameric complex in other placental cell types. The pentameric complex allows viral tropism of placental trophoblasts, endothelial cells, epithelial cells, leukocytes and monocytes. This review outlines HCMV ligands and target receptor proteins in congenital HCMV infection.

The Role of Congenital Cytomegalovirus Infection in Adverse Birth Outcomes: A Review of the Potential Mechanisms

Human cytomegalovirus (CMV) is a major cause of nonhereditary adverse birth outcomes, including hearing and visual loss, neurologic deficits, and intrauterine growth retardation (IUGR), and may contribute to outcomes such as stillbirth and preterm delivery. However, the mechanisms by which CMV could cause adverse birth outcomes are not fully understood. This study reviewed proposed mechanisms underlying the role of CMV in stillbirth, preterm birth, and IUGR. Targeted literature searches were performed in PubMed and Embase to identify relevant articles. Several potential mechanisms were identified from in vitro studies in which laboratory-adapted and low-passage strains of CMV and various human placental models were used. Potential mechanisms identified included impairment of trophoblast progenitor stem cell differentiation and function, impairment of extravillous trophoblast invasiveness, dysregulation of Wnt signaling pathways in cytotrophoblasts, tumor necrosis factor-α mediated apoptosis of trophoblasts, CMV-induced cytokine changes in the placenta, inhibition of indoleamine 2,3-dioxygenase activity, and downregulation of trophoblast class I major histocompatibility complex molecules. Inherent challenges for the field remain in the identification of suitable in vivo animal models. Nonetheless, we believe that our review provides useful insights into the mechanisms by which CMV impairs placental development and function and how these changes could result in adverse birth outcomes.

Investigational Antiviral Therapy Models for the Prevention and Treatment of Congenital Cytomegalovirus Infection during Pregnancy

Congenital cytomegalovirus (HCMV) infection may cause significant fetal malformation, lifelong disease, and, in severe cases, fetal or neonatal death. Placental infection with HCMV is the major mechanism of mother-to-child transmission (MTCT) and fetal injury. Thus, any pharmaceutical antiviral interference to reduce viral load may reduce placental damage, MTCT, and fetal disease. However, there is currently no licensed HCMV antiviral for use during pregnancy. In this study, aciclovir and the HCMV-specific antivirals letermovir, maribavir, and cidofovir were compared with ganciclovir for antiviral effects in model systems of pregnancy, including first-trimester TEV-1 trophoblast cell cultures and third-trimester ex vivo placental explant histocultures. HCMV-infected trophoblasts at 7 days postinfection (dpi) showed an EC₅₀ of 21 μM for aciclovir, 0.0007 μM for letermovir, 0.11 μM for maribavir, and 0.29 μM for cidofovir, relative to 0.42 μM for ganciclovir. Antivirals added at 10 μM showed no cytotoxic effects and did not affect trophoblast cell proliferation (P > 0.9999). Multiple-round HCMV replication measured at 7 dpi showed letermovir, maribavir, and cidofovir treatment inhibited immediate early, early, and true late viral protein expression as assayed on Western blots. Antiviral treatment of HCMV-infected placental explants showed significant inhibition (P < 0.05) of viral replication with letermovir (83.3%), maribavir (83.6%), cidofovir (89.3%), and ganciclovir (82.4%), but not aciclovir (P > 0.9999). In ex vivo model systems, recently trialed HCMV antivirals letermovir and maribavir were effective at inhibiting HCMV replication. They partly fulfil requirements for use as safe and effective therapeutics during pregnancy to control congenital HCMV. Clinical trials of these newer agents would assist assessment of their utility in pregnancy.

Detection of human herpes viruses 1-5 in miscarriage: A case-control study

Background

Miscarriage is the spontaneous pregnancy loss before 24 wk of gestation. The incidence rate of miscarriage over the past few decades has shown steady or even growing trends. Viral intrauterine infections are one of the probable etiological causes of miscarriage. Previous evidence have shown that human herpes viruses (HHVs) could be considered as the potential reasons for intrauterine infections and adverse pregnancy outcomes.

Objective

This case-control study aimed to detect HHV1-5 DNAs in placental tissues and assess their association with miscarriage during the first 24 wk of pregnancy in spontaneous and therapeutic abortions.

Materials and Methods

Placental tissues from 83 women with spontaneous abortions during the first and the second trimesters of pregnancy and 81 women with therapeutic abortion during the same gestational age were collected. The DNA extraction was performed by the phenol/chloroform method. A part of the DNA polymerase gene of HHVs was amplified with multiplex nested-polymerase chain reaction. The polymerase chain reaction products were subjected to sequencing.

Results

The results showed the presence of human cytomegalovirus genome in the placenta of both spontaneous (8.4%) and therapeutic (4.9%) abortions. No statistically significant differences were found between these two groups. The other investigated viruses were not detected here.

Conclusion

In conclusion, like some other studies, no correlation was detected between the HHVs placental infections and the increased risk of spontaneous abortions. In order to find the actual role of HHVs infections in miscarriage, further investigations should be performed on a larger sample size in different areas.

Association between single nucleotide polymorphisms (SNPs) of IL1, IL12, IL28 and TLR4 and symptoms of congenital cytomegalovirus infection

Congenital cytomegalovirus (cCMV) infection is the most common intrauterine infection. A non-specific immune response is the first line of host defense mechanism against human cytomegalovirus (HCMV). There is limited data on associations between Single Nucleotide Polymorphisms (SNPs) in genes involving innate immunity and the risk and clinical manifestation of cCMV infection. The aim of the study was to investigate association between selected SNPs in genes encoding cytokines and cytokine receptors, and predisposition to cCMV infection including symptomatic course of disease and symptoms. A panel of eight SNPs: IL1B rs16944, IL12B rs3212227, IL28B rs12979860, CCL2 rs1024611, DC-SIGN rs735240, TLR2 rs5743708, TLR4 rs4986791, TLR9 rs352140 was analyzed in 233 infants (92 cCMV-infected and 141 healthy controls). Associations between genotyped SNPs and predisposition to cCMV infection and symptoms were analyzed. The association analysis was performed using SNPStats software. No statistically significant association was found between any genotyped SNPs and predisposition to cCMV infection and symptomatic course of disease. In relation to particular symptoms, polymorphism of IL12B rs3212227 was linked to decreased risk of prematurity (OR = 0.37;95%CI,0.14-0.98;p = 0.025), while polymorphism of IL1B rs16944 was linked to reduced risk of splenomegaly (OR = 0.36;95%CI,0.14-0.98; p = 0.034) in infants with cCMV infection. An increased risk of thrombocytopenia was associated with IL28B rs12979860 polymorphism (OR = 2.55;95%CI,1.03-6.32;p = 0.042), while hepatitis was associated with SNP of TLR4rs4986791 (OR = 7.80;95%CI,1.49-40,81; p = 0.024). This is the first study to demonstrate four new associations between SNPs in selected genes (IL1B, IL12B, IL28B, TLR4) and particular symptoms in cCMV disease. Further studies on the role of SNPs in the pathogenesis of cCMV infection and incorporation of selected SNPs in the clinical practice might be considered in the future.

Differential Expression of PDGF Receptor-α in Human Placental Trophoblasts Leads to Different Entry Pathways by Human Cytomegalovirus Strains

Human cytomegalovirus (CMV) is the leading non-genetic cause of fetal malformation in developed countries. CMV placental infection is a pre-requisite for materno-fetal transmission of virus, and fetal infection. We investigated the roles of the viral pentameric complex gH/gL/pUL128-pUL131A, and cellular platelet-derived growth factor receptor-α (PDGFRα) for CMV infection in first trimester extravillous-derived (SGHPL-4) and villous-derived (HTR-8/SVneo) trophoblast cells. Infection with four CMV clinical and laboratory strains (Merlin, TB40E, Towne, AD169), and Merlin deletion mutants of UL128-, UL130-, and UL131A-genes, showed a cell type-dependent requirement of the viral pentameric complex for infection of trophoblast cells. The viral pentameric complex was essential for infection of villous trophoblasts, but non-essential for extravillous trophoblasts. Blocking of PDGFRα in extravillous trophoblasts, which naturally express PDGFRα, inhibited entry of pentameric complex-deficient CMV strains, but not the entry of pentameric positive CMV strains. Transient expression of PDGFRα in villous trophoblasts, which are naturally deficient in PDGFRα, promoted the entry of CMV strains lacking gH/gL/pUL128-pUL131A, but had no effect on entry of pentameric positive CMV strains. These results suggest PDGFRα is an important cell receptor for entry of CMV mutant strains lacking gH/gL/pUL128-pUL131A complexes in some placental cells, suggesting these entry pathways could be potential antiviral targets.

Congenital Transmission of Trypanosoma cruzi: A Review About the Interactions Between the Parasite, the Placenta, the Maternal and the Fetal/Neonatal Immune Responses

Chagas disease (CD), caused by the protozoan parasite Trypanosoma cruzi, is considered a neglected tropical disease by the World Health Organization. Congenital transmission of CD is an increasingly relevant public health problem. It progressively becomes the main transmission route over others and can occur in both endemic and non-endemic countries. Though most congenitally infected newborns are asymptomatic at birth, they display higher frequencies of prematurity, low birth weight, and lower Apgar scores compared to uninfected ones, and some suffer from severe symptoms. If not diagnosed and treated, infected newborns are at risk of developing disabling and life-threatening chronic pathologies later in life. The success or failure of congenital transmission depends on interactions between the parasite, the placenta, the mother, and the fetus. We review and discuss here the current knowledge about these parameters, including parasite virulence factors such as exovesicles, placental tropism, potential placental defense mechanisms, the placental transcriptome of infected women, gene polymorphism, and the maternal and fetal/neonatal immune responses, that might modulate the risk of T. cruzi congenital transmission.

Host Genetics of Cytomegalovirus Pathogenesis

Human cytomegalovirus (HCMV) is a ubiquitous herpes virus (human herpes virus 5) with the highest morbidity and mortality rates compared to other herpes viruses. Risk groups include very young, elderly, transplant recipient, and immunocompromised individuals. HCMV may cause retinitis, encephalitis, hepatitis, esophagitis, colitis, pneumonia, neonatal infection sequelae, inflammatory, and age-related diseases. With an arsenal of genes in its large genome dedicated to host immune evasion, HCMV can block intrinsic cellular defenses and interfere with cellular immune responses. HCMV also encodes chemokines, chemokine receptors, and cytokines. Therefore, genes involved in human viral defense mechanisms and those encoding proteins targeted by the CMV proteins are candidates for host control of CMV infection and reactivation. Although still few in number, host genetic studies are producing valuable insights into biological processes involved in HCMV pathogenesis and HCMV-related diseases. For example, genetic variants in the immunoglobulin GM light chain can influence the antibody responsiveness to CMV glycoprotein B and modify risk of HCMV-related diseases. Moreover, CMV infection following organ transplantation has been associated with variants in genes encoding toll-like receptors (TLRs), programmed death-1 (PD-1), and interleukin-12p40 (IL-12B). A KIR haplotype (2DS4+) is proposed to be protective for CMV activation among hematopoietic stem cell transplant patients. Polymorphisms in the interferon lambda 3/4 (IFNL3/4) region are shown to influence susceptibility to CMV replication among solid organ transplant patients. Interestingly, the IFNL3/4 region is also associated with AIDS-related CMV retinitis susceptibility in HIV-infected patients. Likewise, interleukin-10 receptor 1 (IL-10R1) variants are shown to influence CMV retinitis development in patients with AIDS. Results from genome-wide association studies suggest a possible role for microtubule network and retinol metabolism in anti-CMV antibody response. Nevertheless, further genetic epidemiological studies with large cohorts, functional studies on the numerous HCMV genes, and immune response to chronic and latent states of infection that contribute to HCMV persistence are clearly necessary to elucidate the genetic mechanisms of CMV infection, reactivation, and pathogenesis.

Human Vascular Pericytes and Cytomegalovirus Pathobiology

Pericytes are multipotent cells of the vascular system with cytoplasmic extensions proximal to endothelial cells that occur along the abluminal surface of the endothelium. The interactions between endothelial cells and pericytes are essential for proper microvascular formation, development, stabilization, and maintenance. Pericytes are essential for the regulation of paracellular flow between cells, transendothelial fluid transport, angiogenesis, and vascular immunosurveillance. They also influence the chemical composition of the surrounding microenvironment to protect endothelial cells from potential harm. Dysregulation or loss of pericyte function can result in microvascular instability and pathological consequences. Human pericytes have been shown to be targets for human cytomegalovirus (HCMV) infection and lytic replication that likely contribute to vascular inflammation. This review focuses on human vascular pericytes and their permissiveness for HCMV infection. It also discusses their implication in pathogenesis in the blood⁻brain barrier (BBB), the inner blood⁻retinal barrier (IBRB), the placenta⁻blood barrier, and the renal glomerulus as well as their potential role in subclinical vascular disease.

Prospective Cohort Study of Congenital Cytomegalovirus Infection during Pregnancy with Fetal Growth Restriction: Serologic Analysis and Placental Pathology

OBJECTIVE

To investigate prospectively the prevalence of congenital cytomegalovirus (CMV) infection and the pathologic features of the placenta in cases of fetal growth restriction (FGR).

STUDY DESIGN

Forty-eight pregnant women who were diagnosed with FGR during pregnancy were enrolled for 15 months. Maternal CMV serologic tests, pathologic examinations of the placenta, and newborn urinary CMV-DNA polymerase chain reaction tests were performed in all the cases. The clinical characteristics and laboratory findings of the pregnant women and their newborns were collected. Biomarkers for inflammation, angiogenesis, and placental hormones were measured in the maternal serum at FGR diagnosis or in the neonatal urine at birth.

RESULTS

One of the 48 cases with FGR was a congenital CMV infection. CMV antigen was detected in the placenta of 7 cases with FGR. The change rate of the estimated fetal body weight was significantly lower in FGR cases with placental CMV detection. Placental villitis was observed more frequently in FGR cases with placental CMV detection. Human placental lactogen was significantly decreased in FGR cases with placental CMV detection. Increased C-reactive protein and serum amyloid A levels in the maternal serum were observed more frequently in FGR cases with placental CMV detection. Newborn urine β-2 microglobulin levels were significantly higher in FGR cases with placental CMV detection.

CONCLUSIONS

Serologic tests for maternal CMV, the change rate of the estimated fetal body weight, analysis of several biomarkers, and placental pathologic examinations might be helpful in comprehensively predicting the possibility of congenital CMV infection.

Roles of GP33, a guinea pig cytomegalovirus-encoded G protein-coupled receptor homolog, in cellular signaling, viral growth and inflammation in vitro and in vivo

Cytomegaloviruses (CMVs) encode cellular homologs to evade host immune functions. In this study, we analyzed the roles of GP33, a guinea pig CMV (GPCMV)-encoded G protein-coupled receptor (GPCR) homolog, in cellular signaling, viral growth and pathogenesis. The cDNA structure of GP33 was determined by RACE. The effects of GP33 on some signaling pathways were analyzed in transient transfection assays. The redET two-step recombination system for a BAC containing the GPCMV genome was used to construct a mutant GPCMV containing an early stop codon in the GP33 gene (Δ33) and a rescued GPCMV (r33). We found the following: 1) GP33 activated the CRE- and NFAT-, but not the NFκB-mediated signaling pathway. 2) GP33 was dispensable for infection in tissue cultures and in normal animals. 3) In pregnant animals, viral loads of r33 in the livers, lungs, spleens, and placentas at 6 days post-infection were higher than those of Δ33, although the viruses were cleared by 3 weeks post-infection. 4) The presence of GP33 was associated with frequent lesions, including alveolar hemorrhage in the lungs, and inflammation in the lungs, livers, and spleens of the dams. Our findings suggest that GP33 has critical roles in the pathogenesis of GPCMV during pregnancy. We hypothesize that GP33-mediated signaling activates cytokine secretion from the infected cells, which results in inflammation in some of the maternal organs and the placentas. Alternatively, GP33 may facilitate transient inflammation that is induced by the chemokine network specific to the pregnancy.

Cytomegalovirus (CMV) is a major pathogen that causes congenital diseases, including birth defects and developmental abnormalities in newborns. Better understanding of the immune evasion mechanisms may open the way to the development of new types of live attenuated vaccines for congenital CMV infection. In contrast to murine and rat CMVs, guinea pig CMV (GPCMV) causes infection in utero, which makes GPCMV animal models a useful tool for understanding the pathogenesis of congenital infection and evaluation of vaccine strategies. By constructing a GPCMV mutant lacking GP33, a viral G protein-coupled receptor homolog, this study found that GP33 was involved in the induction of significant inflammatory responses in pregnant but not in normal animals. As GP33 activated the NFAT- and CRE-, but not the NFκB-signal pathway, it is plausible that GP33 enhanced cytokine expression, which results in pathogenic outcomes in the maternal organs and placentas.

Cytokine-Mediated Tissue Injury in Non-human Primate Models of Viral Infections

Viral infections trigger robust secretion of interferons and other antiviral cytokines by infected and bystander cells, which in turn can tune the immune response and may lead to viral clearance or immune suppression. However, aberrant or unrestricted cytokine responses can damage host tissues, leading to organ dysfunction, and even death. To understand the cytokine milieu and immune responses in infected host tissues, non-human primate (NHP) models have emerged as important tools. NHP have been used for decades to study human infections and have played significant roles in the development of vaccines, drug therapies and other immune treatment modalities, aided by an ability to control disease parameters, and unrestricted tissue access. In addition to the genetic and physiological similarities with humans, NHP have conserved immunologic properties with over 90% amino acid similarity for most cytokines. For example, human-like symptomology and acute respiratory syndrome is found in cynomolgus macaques infected with highly pathogenic avian influenza virus, antibody enhanced dengue disease is common in neotropical primates, and in NHP models of viral hepatitis cytokine-induced inflammation induces severe liver damage, fibrosis, and hepatocellular carcinoma recapitulates human disease. To regulate inflammation, anti-cytokine therapy studies in NHP are underway and will provide important insights for future human interventions. This review will provide a comprehensive outline of the cytokine-mediated exacerbation of disease and tissue damage in NHP models of viral infections and therapeutic strategies that can aid in prevention/treatment of the disease syndromes.

Human cytomegalovirus utilises cellular dual-specificity tyrosine phosphorylation-regulated kinases during placental replication

INTRODUCTION

Congenital cytomegalovirus (HCMV) infection may cause significant fetal malformation and in severe cases fetal and neonatal death. Fetal injury may be caused indirectly by the placental response to infection. Dual-specificity tyrosine phosphorylation-regulated kinases (DYRKs) have recently been identified as critical kinases for HCMV replication. In this study we provide first evidence that DYRK1A and DYRK1B are utilised during HCMV placental replication.

METHODS

DYRK expression was investigated in AD169- and Merlin-infected TEV-1 trophoblast cells, ex vivo placental explants and naturally infected clinical placentae by immunofluorescence, western blot, co-immunoprecipitation and RT-qPCR.

RESULTS

HCMV-infected placental cells showed accumulation and re-localisation of DYRK1A and DYRK1B protein to areas of cytoplasmic virion assembly complexes and nuclear viral replication compartments, respectively. This accumulation was a result of upregulated DYRK1A/B protein expression with HCMV inducing up to a 5.3-fold increase in DYRK1A and up to a 4.7-fold increase in DYRK1B protein, relative to mock-infected TEV-1 cells (p < 0.0001). Increased DYRK protein expression was correlated with DYRK1A/B mRNA upregulation, with HCMV-infected cells showing up to a 3.7-fold increase and 2.9-fold increase in DYRK1A and DYRK1B mRNA levels respectively (p < 0.05). Protein-protein interactions were detected between DYRK1A/1B complexes and HCMV immediate early IE2p86, early pp65 and pUL44 and late pp150 proteins. Treatment of HCMV-infected TEV-1 cells and placental explants with DYRK inhibitors significantly inhibited HCMV replication (p < 0.05) indicating these cellular kinases are required during HCMV placental replication.

CONCLUSION

HCMV modulates cellular DYRKs during placental replication which may have implications for congenital HCMV pathogenesis and represent promising antiviral targets.

Extracellular vesicles generated by placental tissues ex vivo: A transport system for immune mediators and growth factors

PROBLEM

To study the mechanisms of placenta function and the role of extracellular vesicles (EVs) in pregnancy, it is necessary to develop an ex vivo system that retains placental cytoarchitecture and the primary metabolic aspects, in particular the release of EVs and soluble factors. Here, we developed such a system and investigated the pattern of secretion of cytokines, growth factors, and extracellular vesicles by placental villous and amnion tissues ex vivo.

METHODS OF STUDY

Placental villous and amnion explants were cultured for 2 weeks at the air/liquid interface and their morphology and the released cytokines and EVs were analyzed. Cytokines were analyzed with multiplexed bead assays, and individual EVs were analyzed with recently developed techniques that involved EV capture with magnetic nanoparticles coupled to anti-EV antibodies and flow cytometry.

RESULTS

Ex vivo tissues (i) remained viable and preserved their cytoarchitecture; (ii) maintained secretion of cytokines and growth factors; (iii) released EVs of syncytiotrophoblast and amnion epithelial cell origins that contain cytokines and growth factors.

CONCLUSION

A system of ex vivo placental villous and amnion tissues can be used as an adequate model to study placenta metabolic activity in normal and complicated pregnancies, in particular to characterize EVs by their surface markers and by encapsulated proteins. Establishment and benchmarking the placenta ex vivo system may provide new insight in the functional status of this organ in various placental disorders, particularly regarding the release of EVs and cytokines. Such EVs may have a prognostic value for pregnancy complications.

Zika-virus-infected human full-term placental explants display pro-inflammatory responses and undergo apoptosis

Zika virus (ZIKV) is a flavivirus that has been highly correlated with the development of neurological disorders and other malformations in newborns and stillborn fetuses after congenital infection. This association is supported by the presence of ZIKV in the fetal brain and amniotic fluid, and findings suggest that infection of the placental barrier is a critical step for fetal ZIKV infection in utero. Therefore, relevant models to investigate the interaction between ZIKV and placental tissues are essential for understanding the pathogenesis of Zika syndrome. In this report, we demonstrate that explant tissue from full-term human placentas sustains a productive ZIKV infection, though the results depend on the strain. Viral infection was found to be associated with pro-inflammatory cytokine expression and apoptosis of the infected tissue, and these findings confirm that placental explants are targets of ZIKV replication. We propose that human placental explants are useful as a model for studying ZIKV infection ex vivo.

Maternal and fetal cytomegalovirus infection: diagnosis, management, and prevention

Congenital cytomegalovirus infection is a major cause of central nervous system and sensory impairments that affect cognition, motor function, hearing, language development, vestibular function, and vision. Although the importance of congenital cytomegalovirus infection is readily evident, the vast majority of maternal and fetal infections are not identified, even in developed countries. Multiple studies of prenatal cytomegalovirus infections have produced a body of knowledge that can inform the clinical approach to suspected or proven maternal and fetal infection. Reliable diagnosis of cytomegalovirus infection during pregnancy and accurate diagnosis of fetal infection are a reality. Approaches to preventing the transmission of cytomegalovirus from mother to fetus and to the treatment of fetal infection are being studied. There is evidence that public health approaches based on hygiene can dramatically reduce the rate of primary maternal cytomegalovirus infections during pregnancy. This review will consider the epidemiology of congenital cytomegalovirus infection, the diagnosis and management of primary infection during pregnancy, and approaches to preventing maternal infection.

Update on treatment of cytomegalovirus infection in pregnancy and of the newborn with congenital cytomegalovirus

PURPOSE OF REVIEW

The purpose of this review is to assess the recent studies of therapy of pregnant women and neonates, aimed at preventing the consequences of congenital cytomegalovirus (CMV) infection.

RECENT FINDINGS

A recent randomized controlled trial of treatment of CMV during pregnancy with hyperimmune globulin did not show significant efficacy in prevention of foetal infection and morbidity, although there was a trend towards improvement with treatment. Trials of antiviral therapy of the mother during pregnancy have involved small numbers only, confounded by ethical and practical difficulties, and further studies are needed to demonstrate whether or not antivirals are useful and well tolerated in this setting.Antiviral treatment of neonatal CMV acquired congenitally has been studied in well controlled trials and the antiviral valganciclovir has shown efficacy in reducing the more severe outcomes. Trials are ongoing of the use of antivirals in less severe disease, although results are likely to take several years.

SUMMARY

Congenital CMV infection is the most frequent cause of congenital malformation in developed countries, with a symptomatic prevalence of 0.64% of all live births. Infection may result in neurodevelopmental delay, foetal or neonatal death, and most frequently, sensorineural hearing loss. Successful control of viral infections during pregnancy and in the newborn period is essential in reducing early and late morbidity and mortality. Control of congenital CMV infection may be via primary prevention methods such as reducing contact with the pathogen, improved hygiene - both for the pregnant mother and for the neonate, or secondary prevention via reduction of vertical transmission from mother to foetus and reduction in consequences of infection by treatment of infected pregnant women and infected neonates.

The immune response against Trypanosoma cruzi in the human placenta

Congenital Chagas disease, caused by Trypanosoma cruzi (T. cruzi), is partially responsible for the increasing globalization of Chagas disease despite its low transmission. During congenital transmission, the parasite reaches the fetus by crossing the placental barrier. However, the success or impairment of congenital transmission of the parasite is the product of a complex interaction between the parasite, the maternal and fetus/newborn immune responses and placental factors. There is other evidence apart from the low congenital transmission rates, which suggests the presence of defense mechanisms against T. cruzi. Thus, the typical amastigote nests (intracellular parasites) cannot be observed in placentas from mothers with chronic Chagas disease nor in human placental chorionic villi explants infected in vitro with the parasite. In the latter, only a few parasite antigens and DNA are identified. Accordingly, other infections of the placenta are not commonly observed. All these evidences suggest that the placenta can mount defense mechanisms against T. cruzi.

Maternal immune correlates of protection against placental transmission of cytomegalovirus

Human cytomegalovirus (HCMV) is the most common congenitally transmitted pathogen worldwide, impacting an estimated 1 million newborns annually. In a subset of infected infants, congenital HCMV causes severe, long-lasting sequelae, including deafness, microcephaly, neurodevelopmental delay, and even death. Accordingly, a maternal vaccine to prevent congenital HCMV infection continues to be a top public health priority. Nevertheless, all vaccines tested to date have failed to meet clinical trial endpoints. Maternal immunity provides partial protection against congenital HCMV transmission, as vertical transmission from seropositive mothers is relatively rare. Therefore, an understanding of the maternal immune correlates of protection against HCMV congenital infection will be critical to inform design of an efficacious maternal vaccine. This review summarizes our understanding of the innate and adaptive immune correlates of protection against congenital transmission of HCMV, and discusses the advantages and applications of a novel nonhuman primate model of congenital CMV transmission to aid in rational vaccine design and evaluation.

Toll-like receptor-2 mediates local innate immune response against Trypanosoma cruzi in ex vivo infected human placental chorionic villi explants

BACKGROUND

Congenital Chagas disease is caused by the protozoan parasite Trypanosoma cruzi that must cross the placental barrier during transmission. The trophoblast constitutes the first tissue in contact with the maternal-blood circulating parasite. Importantly, the congenital transmission rates are low, suggesting the presence of local placental defense mechanisms. On the other hand, the placenta is considered an immune regulatory organ since it acts as a modulator of fetal and maternal immune responses. We have previously proposed that local placental factors, such as the epithelial turnover of the trophoblast and the innate immune response initiated by Toll-like receptors (TLRs), might prevent parasite infection and congenital transmission. Here, we studied in an ex vivo infected human placental chorionic villi explant HPCVE model, the relationship between TLR-2 activation in response to T. cruzi trypomastigotes, the secreted profile of cytokines, the integrity of the placental barrier and the expression of trophoblast turnover markers.

RESULTS

TLR-2 inhibition increases the parasite induced histopathological damage, prevents secretion of IL-6 and IL-10, decreases expression of PCNA (proliferation marker) and of β-hCG (differentiation marker) while increasing caspase 3 activity (cell death marker).

CONCLUSION

Our results suggest that TLR-2 is not only involved in the local secretion of cytokines but also regulates, at least partially, the trophoblast turnover.

Placental pericytes and cytomegalovirus infectivity: Implications for HCMV placental pathology and congenital disease

PROBLEM

Placental pericytes are essential for placental microvascular function, stability, and integrity. Mechanisms of human cytomegalovirus (HCMV) pathogenesis incorporating placental pericytes are unknown.

METHOD OF STUDY

HCMV-infected placental tissue was stained by dual-labeled immunohistochemistry. Primary placental pericytes, cytotrophoblasts, and villous fibroblasts were exposed to HCMV; and infectivity was analyzed by microscopy and immunofluorescence. Cytokine expression was examined by Luminex assay. A HCMV-GFP recombinant virus was used to examine replication kinetics.

RESULTS

Immunohistochemistry showed HCMV in trophoblast and the villous core with T-cell and macrophage infiltration. Primary HCMV isolate from a patient (SBCMV)- infected pericytes showed dysregulation of proinflammatory and angiogenic cytokines when compared to control cells. A tri-cell model of the villous floor showed a unique expression profile. Finally, we show pericytes infected in vivo with HCMV in placental tissue from a congenitally infected child.

CONCLUSION

Placental pericytes support HCMV replication, inducing proinflammatory and angiogenic cytokines that likely contribute to viral dissemination, placenta inflammation, and dysregulation of placental angiogenesis.

Cytokine gene polymorphism associations with congenital cytomegalovirus infection and sensorineural hearing loss

Cytomegalovirus (CMV) is the most common viral agent of congenital infections and a leading nongenetic cause of sensorineural hearing loss (SNHL). The host immunologic factors that render a developing foetus prone to intrauterine CMV infection and development of hearing loss are unknown. The aim of this study was to assess the potential associations between the polymorphisms within cytokine and cytokine receptors genes, and the risk of congenital CMV infection, and the hearing outcome. A panel of 11 candidate single nucleotide polymorphisms (SNPs): TNF rs1799964, TNF rs1800629, TNFRSF1A rs4149570, IL1B rs16944, IL1B rs1143634, IL10 rs1800896, IL10RA rs4252279, IL12B rs3212227, CCL2 rs1024611, CCL2 rs13900, CCR5 rs333 was genotyped in 470 infants (72 with confirmed intrauterine CMV infection and 398 uninfected controls), and related to congenital CMV infection, and the outcome. In multivariate analysis, the IL1B rs16944 TT and TNF rs1799964 TC genotypes were significantly associated with intrauterine CMV infection (aOR = 2.32; 95% CI, 1.11–4.89; p = 0.032, and aOR = 2.17, 95% CI, 1.25–3.77; p = 0.007, respectively). Twenty-two out of 72 congenitally infected newborns had confirmed SNHL. Carriers of CT or TT genotype of CCL2 rs13900 had increased risk of hearing loss at birth and at 6 months of age (aOR = 3.59; p = 0.028 and aOR = 4.10; p = 0.039, respectively). This is the first study to report an association between SNPs in IL1B, TNF, and CCL2, and susceptibility to congenital CMV infection (IL1B and TNF) and SNHL (CCL2).

Cytomegalovirus in pregnancy and the neonate

Congenital cytomegalovirus (CMV) remains a leading cause of disability in children. Understanding the pathogenesis of infection from the mother via the placenta to the neonate is crucial if we are to produce new interventions and provide supportive mechanisms to improve the outcome of congenitally infected children. In recent years, some major goals have been achieved, including the diagnosis of primary maternal CMV infection in pregnant women by using the anti-CMV IgG avidity test and the diagnosis and prognosis of foetal CMV infection by using polymerase chain reaction real-time tests to detect and quantify the virus in amniotic fluid. This review summarises recent advances in our understanding and highlights where challenges remain, especially in vaccine development and anti-viral therapy of the pregnant woman and the neonate. Currently, no therapeutic options during pregnancy are available except those undergoing clinical trials, whereas valganciclovir treatment is recommended for congenitally infected neonates with moderately to severely symptomatic disease.

Testing for Cytomegalovirus in Pregnancy

Congenital cytomegalovirus (CMV) infection represents a relevant cause of deafness and neurological damage in newborns. Intrauterine CMV transmission might result after primary or nonprimary infections, though at different rates (30% versus 0.2%, respectively). At present, a prenatal diagnosis of CMV infection is based mainly on maternal serology, the detection of CMV-DNA in amniotic fluid and fetal blood, and ultrasound (US) and magnetic resonance imaging (MRI). Recent evidences suggest that congenital CMV infection may be an immune-mediated disease and that evaluation of humoral and especially T-cell immunities may improve the overall prenatal diagnosis. This review summarizes the most recent advancements in the diagnosis of maternal and prenatal CMV infections.

Trophoblast cells inhibit neutrophil extracellular trap formation and enhance apoptosis through vasoactive intestinal peptide-mediated pathways

STUDY QUESTION

Do human trophoblast cells modulate neutrophil extracellular trap (NET) formation, reactive oxygen species (ROS) synthesis and neutrophil apoptosis through mechanisms involving vasoactive intestinal peptide (VIP)?

SUMMARY ANSWER

Trophoblast cells inhibited NET formation and ROS synthesis and enhanced neutrophil apoptosis through VIP-mediated pathways in a model of maternal-placental interaction.

WHAT IS KNOWN ALREADY

Immune homeostasis maintenance at the maternal-placental interface is mostly coordinated by trophoblast cells. Neutrophil activation and NET formation increases in pregnancies complicated by exacerbated pro-inflammatory responses. VIP has anti-inflammatory and immunosuppressant effects and is synthesized by trophoblast cells.

STUDY DESIGN, SIZE, DURATION

This is a laboratory-based observational study that sampled circulating neutrophils from 50 healthy volunteers to explore their response in vitro to factors derived from human trophoblast cells.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Peripheral blood neutrophils were isolated from healthy volunteers and tested in vitro with first trimester trophoblast cell line (Swan-71 and HTR8) conditioned media (CM) or with VIP. The effect of VIP and trophoblast CM on NET formation was assessed by co-localization of elastase and DNA by confocal microscopy, DNA release and elastase activity measurement. Neutrophil apoptosis was determined by flow cytometry or fluorescence microscopy. ROS formation was assessed by flow cytometry with a fluorescent probe. VIP silencing was performed by siRNA transfection. For phagocytosis of apoptotic neutrophils, autologous monocytes were sampled, and engulfment and cytokines were assessed by flow cytometry and ELISA.

MAIN RESULTS AND THE ROLE OF CHANCE

Trophoblast CM and 10 nM VIP promoted neutrophil deactivation by preventing phorbol myristate acetate-induced NET formation and ROS synthesis while they increased neutrophil spontaneous apoptosis and reversed the anti-apoptotic effect of lipopolysaccharide (all P < 0.05 versus control). The effects of trophoblast CM were prevented by a VIP antagonist or when VIP knocked-down trophoblast cells were used (P < 0.05 versus control). Neutrophils driven to apoptosis by trophoblast CM could be rapidly engulfed by monocytes without increasing IL-12 production.

LARGE SCALE DATA

Not applicable.

LIMITATIONS, REASONS FOR CAUTION

The mechanisms of neutrophil deactivation by trophoblast VIP are based on the results obtained with neutrophils drawn from peripheral blood of healthy individuals interacting with trophoblast cell lines in vitro. These studies were designed to investigate biological processes at the cellular and molecular level; therefore, they have the limitations of studies in vitro and it is not possible to ascertain if these mechanisms operate similarly in vivo. We tested 50 neutrophil samples from healthy volunteers that have a normal variability in their responses. Cell lines derived from human trophoblast were used, and we cannot rule out a differential behavior of trophoblast cells in contact with neutrophils in vivo.

WIDER IMPLICATIONS OF THE FINDINGS

Results presented here are consistent with an active mechanism through which neutrophils in contact with trophoblast cells would be deactivated and silently cleared by decidual macrophages throughout pregnancy. They support a novel immunomodulatory role of trophoblast VIP on neutrophils at the placenta, providing new clues for pharmacological targeting of immune and trophoblast cells in pregnancy complications associated with exacerbated inflammation.

STUDY FUNDING/COMPETING INTERESTS

This work was funded by the National Agency of Sciences and Technology (PICT 2011-0144, 2014-0657 and 2013-2177) and University of Buenos Aires (UBACyT 20020130100040BA, 20020150100161BA and 20020130100744BA). The authors declare no competing interests.

Post-traumatic stress in pregnant women with primary cytomegalovirus infection and risk of congenital infection in newborns

BACKGROUND

Substantial evidence indicates that perinatal mental disturbances are associated with the risk for negative maternal-newborn outcomes. A neuroendocrine brain-placenta interaction has been described to explain the association between prenatal stress-related disorders and placental abnormalities. Whether these mechanisms may affect the likelihood of mother-to-child transmission (MTCT) of infections has never been investigated.

AIMS

To evaluate the role of psychological factors in cytomegalovirus (CMV) MTCT in pregnant women with primary CMV infection.

METHOD

A cohort of 276 pregnant women with primary CMV infection underwent assessment of (a) reactive psychopathological symptoms, such as current depressive symptoms and ongoing symptoms of post-traumatic stress disorder; and (b) stable personality traits, such as alexithymia and Type D (distressed) personality. Congenital infection was diagnosed by CMV DNA amplification from blood and/or urine and saliva from newborn at birth.

RESULTS

The occurrence of congenital CMV disease in the newborn was independently predicted by post-traumatic stress symptoms during pregnancy.

CONCLUSIONS

Our findings suggest that psychological stress-related disturbances may weaken the physical and immunological barrier against the mother-to-fetus transmission of viruses.

DECLARATION OF INTEREST

We declare that we have no conflicting interests to disclose.

COPYRIGHT AND USAGE

© The Royal College of Psychiatrists 2016. This is an open access article distributed under the terms of the Creative Commons Non-Commercial, No Derivatives (CC BY-NC-ND) license.

Zika Fetal Neuropathogenesis: Etiology of a Viral Syndrome

The ongoing Zika virus epidemic in the Americas and the observed association with both fetal abnormalities (primary microcephaly) and adult autoimmune pathology (Guillain-Barré syndrome) has brought attention to this neglected pathogen. While initial case studies generated significant interest in the Zika virus outbreak, larger prospective epidemiology and basic virology studies examining the mechanisms of Zika viral infection and associated pathophysiology are only now starting to be published. In this review, we analyze Zika fetal neuropathogenesis from a comparative pathology perspective, using the historic metaphor of "TORCH" viral pathogenesis to provide context. By drawing parallels to other viral infections of the fetus, we identify common themes and mechanisms that may illuminate the observed pathology. The existing data on the susceptibility of various cells to both Zika and other flavivirus infections are summarized. Finally, we highlight relevant aspects of the known molecular mechanisms of flavivirus replication.

Cytomegalovirus (CMV) Enzyme-Linked Immunosorbent Spot Assay but Not CMV QuantiFERON Assay Is a Novel Biomarker To Determine Risk of Congenital CMV Infection in Pregnant Women

Cytomegalovirus (CMV) enzyme-linked immunosorbent spot (ELISPOT) and CMV QuantiFERON assays were examined as potential biomarkers predictive of congenital CMV (cCMV) transmission. Fifty-seven pregnant women with primary CMV infection and 23 with nonprimary CMV infection were recruited in the study. Maternal age, CMV IgG avidity, viremia, and viruria were also included among the potential predictors. Spearman's statistical correlation analysis revealed a positive correlation between the CMV ELISPOT and CMV QuantiFERON assay results (P < 0.001), but only the CMV ELISPOT assay correlated with cCMV (P < 0.001). cCMV was positively correlated with maternal viremia and viruria (P < 0.05) and negatively correlated with CMV IgG avidity (P < 0.01). Maternal age and CMV QuantiFERON assay results were not statistically associated with cCMV. CMV-specific cell-mediated immunity detected by the CMV ELISPOT assay plays a critical role in cCMV.

Risk of congenital cytomegalovirus infection among HIV-exposed uninfected infants is not decreased by maternal nelfinavir use during pregnancy

BACKGROUND

Congenital cytomegalovirus (cCMV) infection is common among infants born to HIV-infected women. Nelfinavir (NFV), an antiretroviral drug that is safe during pregnancy, inhibits CMV replication in vitro at concentrations that standard doses achieve in plasma. We hypothesized that infants born to women receiving NFV for prevention of mother-to-child transmission of HIV (PMTCT) would have a reduced prevalence of cCMV infection.

METHODS

The prevalence of cCMV infection was compared among HIV-uninfected infants whose HIV-infected mothers either received NFV for >4 weeks during pregnancy (NFV-exposed) or did not receive any NFV in pregnancy (NFV-unexposed). CMV PCR was performed on infant blood samples collected at <3 weeks from birth.

RESULTS

Of the 1,255 women included, 314 received NFV for >4 weeks during pregnancy and 941 did not receive any NFV during pregnancy. The overall prevalence of cCMV infection in the infants was 2.2%, which did not differ by maternal NFV use. Maternal CD4 T cell counts were inversely correlated with risk of cCMV infection, independent of the time NFV was initiated during gestation. Infants with cCMV infection were born 0.7 weeks earlier (P = 0.010) and weighed 170 g less (P = 0.009) than uninfected infants.

CONCLUSION

Among HIV-exposed uninfected infants, cCMV infection was associated with adverse perinatal outcomes. NFV use in pregnancy was not associated with protection against cCMV. Safe and effective strategies to prevent cCMV infection are needed.

Pregnancy, the placenta and Zika virus (ZIKV) infection

Zika virus (ZIKV) infections have been recognised in Africa and Asia since 1940. The virus is in the family Flaviviridae and genus Flavivirus, along with Dengue, Japanese encephalitis virus, Tick borne encephalitis, West Nile virus, and Yellow fever virus. These viruses share biological characteristics of an envelope, icosahedral nucleocapsid, and a non-segmented, positive sense, single-strand RNA genome of ~10kb encoding three structural proteins (capsid C pre-membrane/membrane PrM/M, envelope E), and seven non-structural proteins (NS1, NS2A, NS2B, NS3, NS4A, NS4B and NS5). ZIKV has three known genotypes; the West African (Nigerian cluster), East African (MR766 prototype cluster), and Asian strains. Virus sequencing from the most recent South American outbreak suggests this virus is related to the 2013 French Polynesian isolates of Asian lineage.