Targeting Toll-like receptor-4 to tackle preterm birth and fetal inflammatory injury

Inflammatory mechanisms of preterm labor and emerging anti-inflammatory interventions

Preterm birth is a major public health concern, requiring a deeper understanding of its underlying inflammatory mechanisms and to develop effective therapeutic strategies. This review explores the complex interaction between inflammation and preterm labor, highlighting the pivotal role of the dysregulation of inflammation in triggering premature delivery. The immunological environment of pregnancy, characterized by a fragile balance of immune tolerance and resistance, is disrupted in preterm labor, leading to a pathological inflammatory response. Feto-maternal infections, among other pro-inflammatory stimuli, trigger the activation of toll-like receptors and the production of pro-inflammatory mediators, promoting uterine contractility and cervical ripening. Emerging anti-inflammatory therapeutics offer promising approaches for the prevention of preterm birth by targeting key inflammatory pathways. From TLR-4 antagonists to chemokine and interleukin receptor antagonists, these interventions aim to modulate the inflammatory environment and prevent adverse pregnancy outcomes. In conclusion, a comprehensive understanding of the inflammatory mechanisms leading to preterm labor is crucial for the development of targeted interventions in hope of reducing the incidence of preterm birth and improving neonatal health outcomes.

The relationship between Toll-like receptor-4 genes and preeclampsia outcomes

PURPOSE

The study aimed to analyse the relationship of the rs4986790 locus of the TLR4 gene with the overall risk of preeclampsia, including both its early and late forms.

METHODS

The study used standard genetic analysis methods such as DNA extraction, PCR amplification, and genotyping of the rs4986790 locus of the TLR4 gene to assess the association with the development of preeclampsia and peripartal stroke in 207 pregnant women from the southern regions of Kazakhstan from 2016 to 2022, of whom 103 had peripartal stroke on the background of preeclampsia (the main group) and 104 preeclampsia (comparative group).

RESULTS

The results of the study demonstrate that the AG and AG + GG genotypes at the rs4986790 locus of the TLR4 gene are significantly associated with an increased risk of developing an early form of preeclampsia. This opens up a new perspective in the identification of genetic markers that can serve as indicators of a tendency to develop preeclampsia in earlier periods of pregnancy.

CONCLUSION

It was noted that the rs4986790 locus did not show a statistically significant association with the risk of late preeclampsia. An important aspect of the study revealed the relationship of genotypes with the development of peripartal stroke on the background of preeclampsia. This study offers practical insights for creating targeted genetic screening and personalised treatments for preeclampsia, aiming to improve patient outcomes. To fully understand the molecular mechanisms underlying the identified association, additional research is required to identify deeper molecular pathways and relationships, and to develop new strategies for the prevention and treatment of preeclampsia.

Preventing Preterm Birth: Exploring Innovative Solutions

This review examines the complexities of preterm birth (PTB), emphasizes the pivotal role of inflammation in the pathogenesis of preterm labor, and assesses current available interventions. Antibiotics, progesterone analogs, mechanical approaches, nonsteroidal anti-inflammatory drugs, and nutritional supplementation demonstrate a limited efficacy. Tocolytic agents, targeting uterine activity and contractility, inadequately prevent PTB by neglecting to act on uteroplacental inflammation. Emerging therapies targeting toll-like receptors, chemokines, and interleukin receptors exhibit promise in mitigating inflammation and preventing PTB.

BKCa channels are involved in spontaneous and lipopolysaccharide-stimulated uterine contraction in late gestation mice†

The large-conductance, voltage-gated, calcium (Ca2+)-activated potassium channel (BKCa) is one of the most abundant potassium channels in the myometrium. Previous work conducted by our group has identified a link between inflammation, BKCa channels and excitability of myometrial smooth muscle cells. Here, we investigate the role of BKCa channels in spontaneous and lipopolysaccharide (LPS)-stimulated uterine contraction to gain a better understanding of the relationship between the BKCa channel and uterine contraction in basal and inflammatory states. Uteri of C57BL/6 J mice on gestational day 18.5 (GD18.5) were obtained and either fixed in formalin or used immediately for tension recording or isolation of primary myocytes for patch-clamp. Paraffin sections were used for immunofluorescenctdetection of BKCa and Toll-like receptor (TLR4). For tension recordings, LPS was administered to determine its effect on uterine contractions. Paxilline, a BKCa inhibitor, was used to dissect the role of BKCa in uterine contraction in basal and inflammatory states. Finally, patch-clamp recordings were performed to investigate the relationship between LPS, the BKCa channel and membrane currents in mouse myometrial smooth muscle cells (mMSMCs). We confirmed the expression of BKCa and TLR4 in the myometrium of GD18.5 mice and found that inhibiting BKCa channels with paxilline suppressed both spontaneous and LPS-stimulated uterine contractions. Furthermore, application of BKCa inhibitors (paxilline or iberiotoxin) after LPS inhibited BKCa channel activity in mMSMCs. Moreover, pretreatment with BKCa inhibitor or the TLR4 inhibitor suppressed LPS-activated BKCa currents. Our study demonstrates that BKCa channels are involved in both basal and LPS-stimulated uterine contraction in pregnant mice.

Dysbiotic Vaginal Microbiota Induces Preterm Birth Cascade via Pathogenic Molecules in the Vagina

Dysbiotic vaginal microbiota (DVM) disturb the vaginal environment, including pH, metabolite, protein, and cytokine profiles. This study investigated the impact of DVM on the vaginal environment in 40 Korean pregnant women and identified predictable biomarkers of birth outcomes. Cervicovaginal fluid (CVF) samples were collected in the third trimester using vaginal swabs, examined for pH, and stored at -80 °C for further analysis. The samples were grouped as full-term (FTB, n = 20) and preterm (PTB, n = 20) births. The microbiota was profiled in the V1-V9 regions. The levels of targeted metabolites, TLR-4, and cytokines were determined. The pH of CVF from PTB (>4.5) was significantly higher than that of the CVF from FTB (>3.5) (p < 0.05). Neonatal gestational age at delivery, birth weight, and Apgar score differed significantly between groups. The relative abundances of beneficial Lactobacillus spp., such as Lactobacillus gasseri, Lactobacillus jensenii, and Bifidobacterium, were higher in FTB, whereas those of pathogenic Enterococcus faecalis, Staphylococcus, Prevotella, Ureaplasma parvum, and Corynebacterium spp. were higher in PTB. Acetate, methanol, TLR-4, and TNF-α levels were negatively correlated with gestational age at delivery and birth weight. Moreover, ethanol, methanol, TLR-4, IL-6, IL-1β, and TNF-α levels were positively correlated with succinate, acetate, acetoacetate, formate, and ammonia. Overall, DVM induces preterm birth via pathogenic molecules in the vagina.

Developmental outcomes with perinatal exposure (DOPE) to prescription opioids

Researchers have found considerable evidence in the past 20 years that perinatal opioid exposure leads to an increased risk of developmental disorders in offspring that persist into adulthood. The use of opioids to treat pain concerning pregnancy, delivery, and postpartum complications has been rising. As a result, communities have reported a 300-400 % increase in Neonatal Opioid Withdrawal Syndrome (NOWS). NOWS represents the initial stage of several behavioral, phenotypic, and synaptic deficits. This review article summarizes the Developmental Outcomes of Perinatal Exposure (DOPE) to prescription opioids. Moreover, we also seek to connect these findings to clinical research that describes DOPE at multiple stages of life. Since specific mechanisms that underlie DOPE remain unclear, this article aims to provide a framework for conceptualizing across all ages and highlight the implications they may have for longevity.

A genome-wide and candidate gene association study of preterm birth in Korean pregnant women

Preterm birth (PTB) refers to delivery before 37 weeks of gestation. Premature neonates exhibit higher neonatal morbidity and mortality rates than term neonates; therefore, it is crucial to predict and prevent PTB. Advancements enable the prediction and prevention of PTB using genetic approaches, especially by investigating its correlation with single nucleotide polymorphisms (SNPs). We aimed to identify impactive and relevant SNPs for the prediction of PTB via whole-genome sequencing analyses of the blood of 31 pregnant women with PTB (n = 13) and term birth (n = 18) who visited the Ewha Womans University Mokdong Hospital from November 1, 2018 to February 29, 2020. A genome-wide association study was performed using PLINK 1.9 software and 256 SNPs were selected and traced through protein-protein interactions. Moreover, a validation study by genotyping was performed on 60 other participants (preterm birth, n = 30; term birth, n = 30) for 25 SNPs related to ion channel binding and receptor complex pathways. Odds ratios were calculated using additive, dominant, and recessive genetic models. The risk of PTB in women with the AG allele of rs2485579 (gene name: RYR2) was significantly 4.82-fold increase, and the risk of PTB in women with the AG allele of rs7903957 (gene name: TBX5) was significantly 0.25-fold reduce. Our results suggest that rs2485579 (in RYR2) can be a genetic marker of PTB, which is considered through the association with abnormal cytoplasmic Ca2+ concentration and dysfunctional uterine contraction due to differences of RYR2 in the sarcoplasmic reticulum.

A systematic review of immune-based interventions for perinatal neuroprotection: closing the gap between animal studies and human trials

BACKGROUND

Perinatal infection/inflammation is associated with a high risk for neurological injury and neurodevelopmental impairment after birth. Despite a growing preclinical evidence base, anti-inflammatory interventions have not been established in clinical practice, partly because of the range of potential targets. We therefore systematically reviewed preclinical studies of immunomodulation to improve neurological outcomes in the perinatal brain and assessed their therapeutic potential.

METHODS

We reviewed relevant studies published from January 2012 to July 2023 using PubMed, Medline (OvidSP) and EMBASE databases. Studies were assessed for risk of bias using the SYRCLE risk of bias assessment tool (PROSPERO; registration number CRD42023395690).

RESULTS

Forty preclinical publications using 12 models of perinatal neuroinflammation were identified and divided into 59 individual studies. Twenty-seven anti-inflammatory agents in 19 categories were investigated. Forty-five (76%) of 59 studies reported neuroprotection, from all 19 categories of therapeutics. Notably, 10/10 (100%) studies investigating anti-interleukin (IL)-1 therapies reported improved outcome, whereas half of the studies using corticosteroids (5/10; 50%) reported no improvement or worse outcomes with treatment. Most studies (49/59, 83%) did not control core body temperature (a known potential confounder), and 25 of 59 studies (42%) did not report the sex of subjects. Many studies did not clearly state whether they controlled for potential study bias.

CONCLUSION

Anti-inflammatory therapies are promising candidates for treatment or even prevention of perinatal brain injury. Our analysis highlights key knowledge gaps and opportunities to improve preclinical study design that must be addressed to support clinical translation.

Elevated expression of Toll-like receptor 4 and cytokines in both serum and myometrium at term may serve as promising biomarkers for uterine activation preceding labor

Objective

Increased inflammation and cytokine levels are considered risk factors and promoters of preterm birth (PTB). However, the regulatory mechanism of pregnancy-related inflammation remains unclear. Toll-like receptor 4 (TLR4) plays a critical role in inflammatory responses in various diseases. Therefore, our study aimed to investigate whether TLR4 is involved in the inflammatory responses during uterine activation for labor, with the goal of identifying potential biomarkers for uterine activation at term.

Materials and methods

We used flow cytometry to detect TLR4 expression on CD14+ maternal blood monocytes in the first, second, and third trimesters. ELISA was employed to measure TLR4 and cytokines levels in the maternal serum of term non-labor (TNL), term labor (TL) women and LPS induced preterm labor and PBS injected controls. TLR4siRNA was transfected into the human myometrial smooth muscle cells (HMSMCs), which were subsequently treated with IL-1β. The mRNA and protein levels of TLR4, uterine contraction-related protein connexin 43 (CX43), oxytocin receptor (OTR), MAPK/NF-κB signaling pathway, and cytokines were analyzed using qRT-PCR, western blotting, and immunohistochemistry.

Results

The study revealed TLR4 expression on CD14+ maternal blood monocytes was higher in the third trimester group compared to the first and second trimester groups (p<0.001). Maternal serum concentrations of TLR4 and cytokines were significantly higher in the TL group than the TNL group (p<0.001). TLR4, OTR, CX43, activated MAPK/NF-κB expression, and cytokines levels were upregulated in TL group, and similarly significantly higher in the LPS-induced preterm group than in the control group. Using the HMSMCs we demonstrated that TLR4siRNA transfection suppressed contractility. Interfering with TLR4 expression reduced the expression of OTR, CX43, cytokines, and MAPK/NF-κB activation. There was a significant positive relationship between TLR4 expression and the inflammatory status in the myometrium. ROC analysis indicated that TLR4 and cytokines may serve as potential biomarkers for predicting uterine activation for labor.

Conclusion

Our data suggest that TLR4 and cytokines can act as stimulators of uterine activation for labor at term. Furthermore, the MAPK/NF-κB pathway appears to be one of the potential signaling pathways mediating TLR4's regulation of parturition initiation.

Establishment of the early prediction models of low-birth-weight reveals influential genetic and environmental factors: a prospective cohort study

BACKGROUND

Low birth weight (LBW) is a leading cause of neonatal morbidity and mortality, and increases various disease risks across life stages. Prediction models of LBW have been developed before, but have limitations including small sample sizes, absence of genetic factors and no stratification of neonate into preterm and term birth groups. In this study, we challenged the development of early prediction models of LBW based on environmental and genetic factors in preterm and term birth groups, and clarified influential variables for LBW prediction.

METHODS

We selected 22,711 neonates, their 21,581 mothers and 8,593 fathers from the Tohoku Medical Megabank Project Birth and Three-Generation cohort study. To establish early prediction models of LBW for preterm birth and term birth groups, we trained AI-based models using genetic and environmental factors of lifestyles. We then clarified influential environmental and genetic factors for predicting LBW in the term and preterm groups.

RESULTS

We identified 2,327 (10.22%) LBW neonates consisting of 1,077 preterm births and 1,248 term births. Our early prediction models archived the area under curve 0.96 and 0.95 for term LBW and preterm LBW models, respectively. We revealed that environmental factors regarding eating habits and genetic features related to fetal growth were influential for predicting LBW in the term LBW model. On the other hand, we identified that genomic features related to toll-like receptor regulations and infection reactions are influential genetic factors for prediction in the preterm LBW model.

CONCLUSIONS

We developed precise early prediction models of LBW based on lifestyle factors in the term birth group and genetic factors in the preterm birth group. Because of its accuracy and generalisability, our prediction model could contribute to risk assessment of LBW in the early stage of pregnancy and control LBW risk in the term birth group. Our prediction model could also contribute to precise prediction of LBW based on genetic factors in the preterm birth group. We then identified parental genetic and maternal environmental factors during pregnancy influencing LBW prediction, which are major targets for understanding the LBW to address serious burdens on newborns' health throughout life.

Integration of transcriptomics and metabolomics reveals the responses of the maternal circulation and maternal-fetal interface to LPS-induced preterm birth in mice

Background

Term birth (TB) and preterm birth (PTB) are characterized by uterine contractions, rupture of the chorioamniotic membrane, decidual activation, and other physiological and pathological changes. In this study, we hypothesize that inflammation can cause changes in mRNA expression and metabolic stability in the placenta, decidua, chorioamniotic membrane, uterus and peripheral blood, ultimately leading to PTB.

Methods

To comprehensively assess the effects of inflammation on mRNA expression and metabolite production in different tissues of pregnancy, we used a mouse PTB model by intraperitoneally injecting lipopolysaccharide (LPS) and integrated transcriptomics and metabolomics studies.

Results

Our analysis identified 152 common differentially expressed genes (DEGs) and 8 common differentially expressed metabolites (DEMs) in the placenta, decidua, chorioamniotic membrane, uterus, and peripheral blood, or placenta and uterus after LPS injection, respectively. Our bioinformatics analysis revealed significant enrichment of the NOD-like receptor signaling pathway (mmu04621), TNF signaling pathway (mmu04668), IL-17 signaling pathway (mmu04657), and NF-kappa B signaling pathway in the transcriptomics of different tissues, and Hormone synthesis, Lysosome, NOD-like receptor signaling pathway, and Protein digest and absorption pathway in metabolomics. Moreover, we found that several upstream regulators and master regulators, including STAT1, STAT3, and NFKB1, were altered after exposure to inflammation in the different tissues. Interaction network analysis of transcriptomics and metabolomics DEGs and DEMs also revealed functional changes in mice intraperitoneally injected with LPS.

Conclusions

Overall, our study identified significant and biologically relevant alterations in the placenta, decidua, chorioamniotic membrane, uterus, peripheral blood transcriptome and the placenta and uterus metabolome in mice exposed to LPS. Thus, a comprehensive analysis of different pregnancy tissues in mice intraperitoneally injected with LPS by combining transcriptomics and metabolomics may help to systematically understand the local and systemic changes associated with PTB caused by inflammation.

Emerging role of toll-like receptors signaling and its regulators in preterm birth: a narrative review

INTRODUCTION

Despite intensive research, preterm birth (PTB) rates have not decreased significantly in recent years due to a lack of understanding of the underlying causes and insufficient treatment options for PTB. We are committed to finding promising biomarkers for the treatment of PTB.

METHODS

An extensive search of the literature was conducted with MEDLINE/PubMed, and in total, 151 studies were included and summarized in the present review.

RESULTS

Substantial evidence supports that the infection and/or inflammatory cascade associated with infection is an early event in PTB. Toll-like receptor (TLR) is a prominent pattern recognition receptor (PRR) found on both immune and non-immune cells, including fetal membrane cells. The activation of TLR downstream molecules, followed by TLR binding to its ligand, is critical for infection and inflammation, leading to the involvement of the TLR signaling pathway in PTB. TLR ligands are derived from microbial components and molecules released by damaged and dead cells. Particularly, TLR4 is an essential TLR because of its ability to recognize lipopolysaccharide (LPS). In this comprehensive overview, we discuss the role of TLR signaling in PTB, focus on numerous host-derived genetic and epigenetic regulators of the TLR signaling pathway, and cover ongoing research and prospective therapeutic options for treating PTB by inhibiting TLR signaling.

CONCLUSION

This is a critical topic because TLR-related molecules and mechanisms may enable obstetricians to better understand the physiological changes in PTB and develop new treatment and prevention strategies.

Metabolites Profiling and Bioassays Reveal Bassia indica Ethanol Extract Protective Effect against Stomach Ulcers Development via HMGB1/TLR-4/NF-κB Pathway

Clinical manifestation of gastric ulcers is frequent, in addition to their costly drug regimens, warranting the development of novel drugs at lower costs. Although Bassia indica is well characterized for its anti-inflammatory and antioxidant potential, capacity of its ethanol extract (BIEE) to prevent stomach ulcers' progression has not been reported. A nuclear protein termed high-mobility group box 1 (HMGB1) plays a key role in the formation of stomach ulcers by triggering a number of inflammatory responses. The main purpose of the current investigation was to evaluate the in vivo anti-inflammatory and anti-ulcerogenic capabilities of BIEE against ethanol-induced gastric ulcers in rats via the HMGB1/TLR-4/NF-B signaling pathway. HMGB1 and Nuclear factor kappa (NF-B) expression, IL-1β and Nrf2 contents showed an increase along with ulcer development, concurrent with an increase in immunohistochemical TLR-4 level. In contrast, pre-treatment with BIEE significantly reduced HMGB1 and Nuclear factor kappa (NF-B) expression levels, IL-1β and Nrf2 contents and ulcer index value. Such protective action was further confirmed based on histological and immunohistochemical TLR-4 assays. Untargeted analysis via UPLC-ESI-Qtof-MS has allowed for the comprehensive characterization of 40 metabolites in BIEE mostly belonged to two main chemical classes, viz., flavonoids and lipids. These key metabolites, particularly flavonoids, suggesting a mediation for the anti-inflammatory and anti-ulcerogenic properties of BIEE, pose it as a promising natural drug regimen for treatment of stomach ulcers.

Maternal Infection and Preterm Birth: From Molecular Basis to Clinical Implications

As the leading cause of neonatal morbidity and mortality, preterm birth is recognized as a major public health concern around the world. The purpose of this review is to analyze the connection between infections and premature birth. Spontaneous preterm birth is commonly associated with intrauterine infection/inflammation. The overproduction of prostaglandins caused by the inflammation associated with an infection could lead to uterine contractions, contributing to preterm delivery. Many pathogens, particularly Chlamydia trachomatis, Neisseria gonorrhoeae, Trichomonas vaginalis, Gardnerella vaginalis, Ureaplasma urealyticum, Mycoplasma hominis, Actinomyces, Candida spp., and Streptococcus spp. have been related with premature delivery, chorioamnionitis, and sepsis of the neonate. Further research regarding the prevention of preterm delivery is required in order to develop effective preventive methods with the aim of reducing neonatal morbidity.

Microbial transmission, colonisation and succession: from pregnancy to infancy

The microbiome has been proven to be associated with many diseases and has been used as a biomarker and target in disease prevention and intervention. Currently, the vital role of the microbiome in pregnant women and newborns is increasingly emphasised. In this review, we discuss the interplay of the microbiome and the corresponding immune mechanism between mothers and their offspring during the perinatal period. We aim to present a comprehensive picture of microbial transmission and potential immune imprinting before and after delivery. In addition, we discuss the possibility of in utero microbial colonisation during pregnancy, which has been highly debated in recent studies, and highlight the importance of the microbiome in infant development during the first 3 years of life. This holistic view of the role of the microbial interplay between mothers and infants will refine our current understanding of pregnancy complications as well as diseases in early life and will greatly facilitate the microbiome-based prenatal diagnosis and treatment of mother-infant-related diseases.

Characterization of methylation profiles in spontaneous preterm birth placental villous tissue

Preterm birth is a global public health crisis which results in significant neonatal and maternal mortality. Yet little is known regarding the molecular mechanisms of idiopathic spontaneous preterm birth, and we have few diagnostic markers for adequate assessment of placental development and function. Previous studies of placental pathology and our transcriptomics studies suggest a role for placental maturity in idiopathic spontaneous preterm birth. It is known that placental DNA methylation changes over gestation. We hypothesized that if placental hypermaturity is present in our samples, we would observe a unique idiopathic spontaneous preterm birth DNA methylation profile potentially driving the gene expression differences we previously identified in our placental samples. Our results indicate the idiopathic spontaneous preterm birth DNA methylation pattern mimics the term birth methylation pattern suggesting hypermaturity. Only seven significant differentially methylated regions fitting the idiopathic spontaneous preterm birth specific (relative to the controls) profile were identified, indicating unusually high similarity in DNA methylation between idiopathic spontaneous preterm birth and term birth samples. We identified an additional 1,718 significantly methylated regions in our gestational age matched controls where the idiopathic spontaneous preterm birth DNA methylation pattern mimics the term birth methylation pattern, again indicating a striking level of similarity between the idiopathic spontaneous preterm birth and term birth samples. Pathway analysis of these regions revealed differences in genes within the WNT and Cadherin signaling pathways, both of which are essential in placental development and maturation. Taken together, these data demonstrate that the idiopathic spontaneous preterm birth samples display a hypermature methylation signature than expected given their respective gestational age which likely impacts birth timing.

Mechanisms of Maternal Diet-Induced Obesity Affecting the Offspring Brain and Development of Affective Disorders

Depression and metabolic disease are common disorders that share a bidirectional relationship and continue to increase in prevalence. Maternal diet and maternal behaviour both profoundly influence the developmental trajectory of offspring during the perinatal period. At an epidemiological level, both maternal depression and obesity during pregnancy have been shown to increase the risk of neuropsychiatric disease in the subsequent generation. Considerable progress has been made to understand the mechanisms by which maternal obesity disrupts the developing offspring gut-brain axis, priming offspring for the development of affective disorders. This review outlines such mechanisms in detail, including altered maternal care, the maternal microbiome, inflammation, breast milk composition, and maternal and placental metabolites. Subsequently, offspring may be prone to developing gut-brain interaction disorders with concomitant changes to brain energy metabolism, neurotransmission, and behaviour, alongside gut dysbiosis. The gut microbiome may act as a key modifiable, and therefore treatable, feature of the relationship between maternal obesity and the offspring brain function. Further studies examining the relationship between maternal nutrition, the maternal microbiome and metabolites, and offspring neurodevelopment are warranted to identify novel therapeutic targets.

Ultra-low-coverage genome-wide association study-insights into gestational age using 17,844 embryo samples with preimplantation genetic testing

BACKGROUND

Very low-coverage (0.1 to 1×) whole genome sequencing (WGS) has become a promising and affordable approach to discover genomic variants of human populations for genome-wide association study (GWAS). To support genetic screening using preimplantation genetic testing (PGT) in a large population, the sequencing coverage goes below 0.1× to an ultra-low level. However, the feasibility and effectiveness of ultra-low-coverage WGS (ulcWGS) for GWAS remains undetermined.

METHODS

We built a pipeline to carry out analysis of ulcWGS data for GWAS. To examine its effectiveness, we benchmarked the accuracy of genotype imputation at the combination of different coverages below 0.1× and sample sizes from 2000 to 16,000, using 17,844 embryo PGT samples with approximately 0.04× average coverage and the standard Chinese sample HG005 with known genotypes. We then applied the imputed genotypes of 1744 transferred embryos who have gestational ages and complete follow-up records to GWAS.

RESULTS

The accuracy of genotype imputation under ultra-low coverage can be improved by increasing the sample size and applying a set of filters. From 1744 born embryos, we identified 11 genomic risk loci associated with gestational ages and 166 genes mapped to these loci according to positional, expression quantitative trait locus, and chromatin interaction strategies. Among these mapped genes, CRHBP, ICAM1, and OXTR were more frequently reported as preterm birth related. By joint analysis of gene expression data from previous studies, we constructed interrelationships of mainly CRHBP, ICAM1, PLAGL1, DNMT1, CNTLN, DKK1, and EGR2 with preterm birth, infant disease, and breast cancer.

CONCLUSIONS

This study not only demonstrates that ulcWGS could achieve relatively high accuracy of adequate genotype imputation and is capable of GWAS, but also provides insights into the associations between gestational age and genetic variations of the fetal embryos from Chinese population.

Cross-Generational Impact of Innate Immune Memory Following Pregnancy Complications

Pregnancy complications can have long-term negative effects on the health of the affected mothers and their children. In this review, we highlight the underlying inflammatory etiologies of common pregnancy complications and discuss how aberrant inflammation may lead to the acquisition of innate immune memory. The latter can be described as a functional epigenetic reprogramming of innate immune cells following an initial exposure to an inflammatory stimulus, ultimately resulting in an altered response following re-exposure to a similar inflammatory stimulus. We propose that aberrant maternal inflammation associated with complications of pregnancy increases the cross-generational risk of developing noncommunicable diseases (i.e., pregnancy complications, cardiovascular disease, and metabolic disease) through a process mediated by innate immune memory. Elucidating a role for innate immune memory in the cross-generational health consequences of pregnancy complications may lead to the development of novel strategies aimed at reducing the long-term risk of disease.

In Vitro Anti-Influenza A Virus H1N1 Effect of Sesquiterpene-Rich Extracts of Carpesium abrotanoides

Due to a high content of sesquiterpenes, Carpesium abrotanoides has been investigated to fully explore its health-promoting properties. Therefore, this work aimed to assess, for the first time, the anti-influenza A virus H1N1 potential of sesquiterpene-targeted fractions of the herb derived from C. abrotanoides. Five compounds, including four sesquiterpenes and one aldehyde, were isolated and identified from the sesquiterpene-rich extracts of C. abrotanoides (SECA), and the contents of three main sesquiterpenes in the SECA were determined. Furthermore, SECA showed a significant protective effect in the MDCK cells infected with influenza A virus (H1N1) in three different conditions: premixed administration, prophylactic administration, and therapeutic administration. SECA can significantly decrease the mRNA expressions of TLR4, MyD88, NF-κB, TNF-α, and IL-6, as well as the protein expressions of TLR4, MyD88, and NF-κB. This result suggests that SECA can resist the influenza A virus H1N1 through the TLR4/MyD88/NF-κB signal pathway.

Single Domain Antibody application in bacterial infection diagnosis and neutralization

Increasing antibiotic resistance to bacterial infections causes a serious threat to human health. Efficient detection and treatment strategies are the keys to preventing and reducing bacterial infections. Due to the high affinity and antigen specificity, antibodies have become an important tool for diagnosis and treatment of various human diseases. In addition to conventional antibodies, a unique class of “heavy-chain-only” antibodies (HCAbs) were found in the serum of camelids and sharks. HCAbs binds to the antigen through only one variable domain Referred to as VHH (variable domain of the heavy chain of HCAbs). The recombinant format of the VHH is also called single domain antibody (sdAb) or nanobody (Nb). Sharks might also have an ancestor HCAb from where SdAbs or V-NAR might be engineered. Compared with traditional Abs, Nbs have several outstanding properties such as small size, high stability, strong antigen-binding affinity, high solubility and low immunogenicity. Furthermore, they are expressed at low cost in microorganisms and amenable to engineering. These superior properties make Nbs a highly desired alternative to conventional antibodies, which are extensively employed in structural biology, unravelling biochemical mechanisms, molecular imaging, diagnosis and treatment of diseases. In this review, we summarized recent progress of nanobody-based approaches in diagnosis and neutralization of bacterial infection and further discussed the challenges of Nbs in these fields.

Physiological TLR4 regulation in human fetal membranes as an explicative mechanism of a pathological preterm case

The integrity of human fetal membranes is crucial for harmonious fetal development throughout pregnancy. Their premature rupture is often the consequence of a physiological phenomenon that has been exacerbated. Beyond all the implied biological processes, inflammation is of primary importance and is qualified as ‘sterile’ at the end of pregnancy. In this study, complementary methylomic and transcriptomic strategies on amnion and choriodecidua explants obtained from the altered (cervix zone) and intact fetal membranes at term and before labour were used. By cross-analysing genome-wide studies strengthened by in vitro experiments, we deciphered how the expression of toll-like receptor 4 (TLR4), an actor in pathological fetal membrane rupture, is controlled. Indeed, it is differentially regulated in the altered zone and between both layers by a dual mechanism: (1) the methylation of TLR4 and miRNA promoters and (2) targeting by miRNA (let-7a-2 and miR-125b-1) acting on the 3’-UTR of TLR4. Consequently, this study demonstrates that fine regulation of TLR4 is required for sterile inflammation establishment at the end of pregnancy and that it may be dysregulated in the pathological premature rupture of membranes.

Macrophages exert homeostatic actions in pregnancy to protect against preterm birth and fetal inflammatory injury

Macrophages are commonly thought to contribute to the pathophysiology of preterm labor by amplifying inflammation — but a protective role has not previously been considered to our knowledge. We hypothesized that given their antiinflammatory capability in early pregnancy, macrophages exert essential roles in maintenance of late gestation and that insufficient macrophages may predispose individuals to spontaneous preterm labor and adverse neonatal outcomes. Here, we showed that women with spontaneous preterm birth had reduced CD209⁺CD206⁺ expression in alternatively activated CD45⁺CD14⁺ICAM3^– macrophages and increased TNF expression in proinflammatory CD45⁺CD14⁺CD80⁺HLA-DR⁺ macrophages in the uterine decidua at the materno-fetal interface. In Cd11b^DTR/DTR mice, depletion of maternal CD11b⁺ myeloid cells caused preterm birth, neonatal death, and postnatal growth impairment, accompanied by uterine cytokine and leukocyte changes indicative of a proinflammatory response, while adoptive transfer of WT macrophages prevented preterm birth and partially rescued neonatal loss. In a model of intra-amniotic inflammation–induced preterm birth, macrophages polarized in vitro to an M2 phenotype showed superior capacity over nonpolarized macrophages to reduce uterine and fetal inflammation, prevent preterm birth, and improve neonatal survival. We conclude that macrophages exert a critical homeostatic regulatory role in late gestation and are implicated as a determinant of susceptibility to spontaneous preterm birth and fetal inflammatory injury.

Pathophysiological Implication of Pattern Recognition Receptors in Fetal Membranes Rupture: RAGE and NLRP Inflammasome

Preterm prelabor ruptures of fetal membranes (pPROM) are a pregnancy complication responsible for 30% of all preterm births. This pathology currently appears more as a consequence of early and uncontrolled process runaway activation, which is usually implicated in the physiologic rupture at term: inflammation. This phenomenon can be septic but also sterile. In this latter case, the inflammation depends on some specific molecules called “alarmins” or “damage-associated molecular patterns” (DAMPs) that are recognized by pattern recognition receptors (PRRs), leading to a microbial-free inflammatory response. Recent data clarify how this activation works and which receptor translates this inflammatory signaling into fetal membranes (FM) to manage a successful rupture after 37 weeks of gestation. In this context, this review focused on two PRRs: the receptor for advanced glycation end-products (RAGE) and the NLRP7 inflammasome.

Trophoblasts Modulate the Ca2+ Oscillation and Contraction of Myometrial Smooth Muscle Cells by Small Extracellular Vesicle- (sEV-) Mediated Exporting of miR-25-3p during Premature Labor

The placenta could transmit information to the maternal circulation via the secretion of small extracellular vesicles (sEVs), but little is known about whether and how these sEVs participate in premature labor (PTL). We speculate that miRNA plays an important role in sEV-mediated fetal-maternal information transmission. The present study was aimed at investigating whether the placenta can regulate the contraction of the maternal myometrium via sEV-mediated transmit of miR-25-3p during PTL. The expression of miR-25-3p and its targets Cav3.2 and SERCA2a in clinical samples, cells, and animal specimens was detected. The role of miR-25-3p was observed in the LPS-induced preterm labor mouse model. The sEVs from HTR-8/SVneo cells were characterized by transmission electron microscopy and nanoparticle tracking analysis. The Ca²⁺ oscillation in HMSMs was analyzed by an intracellular Ca²⁺ change tracking assay on a confocal microscope. The contraction of HMSMs was detected by a collagen matrix contraction assay. We found that miR-25-3p can directly bind to the 3′UTR of Cav3.2 and SERCA2a. The miR-25-3p level was decreased, and the expression of its targets Cav3.2 and SERCA2a was increased in the placenta and myometrium tissues of PTL patients. Forced upregulation of miR-25-3p reduced the oxidative stress and inflammation responses and the incidence of PTL in LPS-treated mice. The expression of miR-25-3p was not changed in LPS-stimulated human myometrial smooth muscle cells (HMSMs) but was strongly reduced in the trophoblast cell and its sEVs. Additionally, the trophoblast cell line HTR-8/SVneo could transmit miR-25-3p into HMSMs via sEVs. The sEVs derived from LPS-stimulated trophoblasts upregulated the expression of Cav3.2 and SERCA2a and triggered Ca²⁺ oscillation as well as the contraction of HMSMs; these effects were partially reversed by the overexpression of miR-25-3p in the trophoblasts. Further, the upregulation of miR-25-3p induced changes of Ca²⁺ oscillation and contraction of HMSMs mediated by sEVs which were also abrogated by the knockdown of miR-25-3p in HMSMs. The results demonstrated that miR-25-3p plays a crucial role in PTL via Cav3.2- and SERCA2a-mediated Ca²⁺ oscillation and contraction of HMSMs. PTL seems to be related to the decreased exosomal miR-25-3p content transmitted by the trophoblasts under inflammatory conditions.

High Mobility Group Box 1 in Pig Amniotic Membrane Experimentally Infected with E. coli O55

Intra-amniotic infections (IAI) are one of the reasons for preterm birth. High mobility group box 1 (HMGB1) is a nuclear protein with various physiological functions, including tissue healing. Its excessive extracellular release potentiates inflammatory reaction and can revert its action from beneficial to detrimental. We infected the amniotic fluid of a pig on the 80th day of gestation with 1 × 10⁴ colony forming units (CFUs) of E. coli O55 for 10 h, and evaluated the appearance of HMGB1, receptor for glycation endproducts (RAGE), and Toll-like receptor (TLR) 4 in the amniotic membrane and fluid. Sham-infected amniotic fluid served as a control. The expression and release of HMGB1 were evaluated by Real-Time PCR, immunofluorescence, immunohistochemistry, and ELISA. The infection downregulated HMGB1 mRNA expression in the amniotic membrane, changed the distribution of HMGB1 protein in the amniotic membrane, and increased its level in amniotic fluid. All RAGE mRNA, protein expression in the amniotic membrane, and soluble RAGE level in the amniotic fluid were downregulated. TLR4 mRNA and protein expression and soluble TLR4 were all upregulated. HMGB1 is a potential target for therapy to suppress the exaggerated inflammatory response. This controlled expression and release can, in some cases, prevent the preterm birth of vulnerable infants. Studies on suitable animal models can contribute to the development of appropriate therapy.

In vitro effects of citral on the human myometrium: Potential adjunct therapy to prevent preterm births

BACKGROUND

Premature infants contribute to infant morbidity and mortality especially in low resource settings. Information on tocolytic and/or anti-inflammatory effects of several plant extracts, such as citral, could help prevent preterm birth cases and reduce the number of preterm infants. The aim of this study was to evaluate the in vitro tocolytic and anti-inflammatory effect of citral on myometrial tissues of the human uterus.

METHODS

Myometrial samples from uteri obtained after hysterectomy were used in functional tests to evaluate the inhibitory effect of citral on PGF-2α induced contractions. The intracellular cyclic adenosine monophosphate (cAMP) levels generated in response to citral in human myometrial homogenates were measured by ELISAs. Forskolin was used as a positive control. The anti-inflammatory effect of citral was determined through the measurement of two pro-inflammatory cytokines, tumor necrosis factor-α (TNFα) and interleukin (IL)-1β, and the anti-inflammatory cytokine IL-10, in human myometrial explants stimulated with lipopolysaccharide (LPS).

RESULTS

Citral was able to induce a significant inhibition of PGF-2α induced contractions at the highest concentration level (p < .05). Citral caused a concentration-dependent increase in myometrial cAMP levels (p < .05) and a concentration-dependent decrease in LPS-induced TNFα and IL-1β production, while IL-10 production increased significantly (p < .05). The anti-inflammatory and tocolytic effects induced by citral could be associated with an increase in cAMP levels in human myometrial samples.

CONCLUSION

These properties place citral as a potentially safe and effective adjuvant agent in preterm birth cases, an obstetric and gynecological problem that requires urgent attention.