Phenotypic and Epigenetic Adaptations of Cord Blood CD4+ T Cells to Maternal Obesity

DNA methylation in cord blood partially mediates the effects of prepregnancy BMI on early childhood offspring BMI

OBJECTIVE

We investigated whether prepregnancy BMI (prePregBMI) in women with obesity was associated with differential DNA methylation (DNAm) in cord blood (CB) and whether DNAm may mediate the association of prePregBMI and early childhood BMI z score (BMIz).

METHODS

From the Treatment of Obese Pregnant Women (TOP) study, 232 mother-child pairs were included. We conducted an epigenome-wide association study on prePregBMI and CB DNAm (450k array), followed by causal mediation analyses to test whether DNAm may mediate effects of prePregBMI on  BMIz at age 36 months (BMIz36).

RESULTS

DNAm at 5345 CpG sites annotated to 2842 genes, which were overrepresented in biological processes linked to carbohydrate metabolism and plasma lipoprotein particle clearance, was associated with prePregBMI (false discovery rate < 10%). Causal mediation analyses of 168 methylation sites associated with BMIz36 (p < 0.05) and overlapping with the 5345 prePregBMI-associated sites identified two sites on SYT7 and DEAF1, partially mediating the effect of prePregBMI on BMIz36 (p ≤ 0.01). After cross-validation, a methylation risk score including these two sites could predict the highest quartile of BMIz36 and fat mass (in grams) with area under the curve = 0.72 (95% CI: 0.58-0.85) and area under the curve = 0.71 (95% CI: 0.58-0.85), respectively.

CONCLUSIONS

CB DNAm at birth may partially mediate effects of prePregBMI on early childhood BMIz36, supporting its plausible role in influencing individual future obesity risk.

Glucose intolerance as a consequence of hematopoietic stem cell dysfunction in offspring of obese mice

OBJECTIVE

Maternal obesity is increasingly common and negatively impacts offspring health. Children of mothers with obesity are at higher risk of developing diseases linked to hematopoietic system abnormalities and metabolism such as type 2 diabetes. Interestingly, disease risks are often dependent on the offspring's sex, suggesting sex-specific reprogramming effect of maternal obesity on offspring hematopoietic stem and progenitor cell (HSPC) function. However, the impact of maternal obesity exposure on offspring HSPC function, and the capability of HSPC to regulate offspring metabolic health is largely understudied. This study aims to test the hypothesis that offspring of obese mice exhibit sex-differences in HSPC function that affect offspring's metabolic health.

METHODS

We first assessed bone marrow hematopoietic stem and progenitor cell phenotype using postnatal day 21 (P21) and 8-week-old C57BL/6J mice born to control and diet-induced obese dams. We also sorted HSPC (Lineage-, Sca1+, cKit + cells) from P21 mice for competitive primary and secondary transplant, as well as transcriptomic analysis. Body weight, adiposity, insulin tolerance test and glucose tolerance tests were performed in primary and secondary transplant recipient animals.

RESULTS

We discovered sex-differences in offspring HSPC function in response to maternal obesity exposure, where male offspring of obese dams (MatOb) showed decreased HSPC numbers and engraftment, while female MatOb offspring remained largely unaffected. RNA-seq revealed immune stimulatory pathways in female MatOb offspring. Finally, only recipients of male MatOb offspring HSPC exhibited glucose intolerance.

CONCLUSIONS

This study demonstrated the lasting effect of maternal obesity exposure on offspring HSPC function and implicates HSPC in metabolic regulation.

Obesity Influences T CD4 Lymphocytes Subsets Profiles in Children and Adolescent's Immune Response

BACKGROUND

Evidence shows that CD4+ T cells are altered in obesity and play a significant role in the systemic inflammation in adults with the disease.

OBJECTIVES

Because the profile of these cells is poorly understood in the pediatric population, this study aims to investigate the profile of CD4+ T lymphocytes and the plasma levels of cytokines in this population.

METHODS

Using flow cytometry, we compared the expression profile of lymphocyte markers, master transcription factors, cytokines, and molecules involved in the regulation of the immune response in CD4+ T cells from children and adolescents with obesity (OB group, n = 20) with those with eutrophy group (EU group, n = 16). Plasma levels of cytokines in both groups were determined by cytometric bead array (CBA).

RESULTS

The OB group presents a lower frequency of CD3+ T cells, as well as a decreased frequency of CD4+ T cells expressing CD28, IL-4, and FOXP3, but an increased frequency of CD4+IL-17A+ cells compared with the EU group. The frequency of CD28 is increased in Th2 and Treg cells in the OB group, whereas CTLA-4 is decreased in all subpopulations compared with the EU group. Furthermore, Th2, Th17, and Treg profiles can differentiate the EU and OB groups. IL-10 plasma levels are reduced in the OB group and negatively correlated with adiposity and inflammatory parameters.

CONCLUSIONS

CD4+ T cells have an altered pattern of expression in children and adolescents with obesity, contributing to the inflammatory state and clinical characteristics of these patients.

A Scoping Review of the Relationship Between Maternal BMI and Offspring Incidence of Respiratory Infection: Where Do We Go From Here?

Introduction

Pregnancy complications, including high maternal BMI, are associated with altered early development and child health outcomes. A growing body of work links the prenatal environment, specifically maternal BMI, with respiratory infections in offspring. In this rapid review, the authors review the literature supporting the hypothesis that high maternal BMI during pregnancy is associated with childhood respiratory infection incidence.

Methods

The authors employed systematic search criteria in known databases-EMBASE, EMCARE, MEDLINE, CINAHL, and PsychINFO-searching from inception to January 2023. Included were primary research studies that involved (1) human pregnancy, (2) pregravid or gestational overweight or obesity, and (3) childhood respiratory infection with or without hospitalization.

Results

Only 7 population-based cohort studies met the criteria, investigating maternal BMI as an exposure and childhood respiratory infection as an outcome (age 6 months to 18 years). Therefore, the authors conducted a qualitative analysis, and outcomes were reported. The authors found that >85% of the albeit few published studies support the hypothesis that maternal BMI may have independent and profound consequences on respiratory infection risk across childhood.

Discussion

This area of research needs large-scale, well-controlled studies to better understand the relationship between maternal BMI and childhood respiratory infection. Possible resources such as cohort catalogs and combined databases are discussed. These findings add to the growing evidence that early environmental factors influence lifelong respiratory health. By incorporating a life course approach to infectious disease risk, policy makers can put this research to work and target health vulnerabilities before they arise.

Developmental Programming of the Fetal Immune System by Maternal Western-Style Diet: Mechanisms and Implications for Disease Pathways in the Offspring

Maternal obesity and over/undernutrition can have a long-lasting impact on offspring health during critical periods in the first 1000 days of life. Children born to mothers with obesity have reduced immune responses to stimuli which increase susceptibility to infections. Recently, maternal western-style diets (WSDs), high in fat and simple sugars, have been associated with skewing neonatal immune cell development, and recent evidence suggests that dysregulation of innate immunity in early life has long-term consequences on metabolic diseases and behavioral disorders in later life. Several factors contribute to abnormal innate immune tolerance or trained immunity, including changes in gut microbiota, metabolites, and epigenetic modifications. Critical knowledge gaps remain regarding the mechanisms whereby these factors impact fetal and postnatal immune cell development, especially in precursor stem cells in bone marrow and fetal liver. Components of the maternal microbiota that are transferred from mothers consuming a WSD to their offspring are understudied and identifying cause and effect on neonatal innate and adaptive immune development needs to be refined. Tools including single-cell RNA-sequencing, epigenetic analysis, and spatial location of specific immune cells in liver and bone marrow are critical for understanding immune system programming. Considering the vital role immune function plays in offspring health, it will be important to understand how maternal diets can control developmental programming of innate and adaptive immunity.

A review of single-cell transcriptomics and epigenomics studies in maternal and child health

Single-cell sequencing technologies enhance our understanding of cellular dynamics throughout pregnancy. We outlined the workflow of single-cell sequencing techniques and reviewed single-cell studies in maternal and child health. We conducted a literature review of single cell studies on maternal and child health using PubMed. We summarized the findings from 16 single-cell atlases of the human and mammalian placenta across gestational stages and 31 single-cell studies on maternal exposures and complications including infection, obesity, diet, gestational diabetes, pre-eclampsia, environmental exposure and preterm birth. Single-cell studies provides insights on novel cell types in placenta and cell type-specific marks associated with maternal exposures and complications.

Cord blood DNA methylation of immune and lipid metabolism genes is associated with maternal triglycerides and child adiposity

OBJECTIVE

Fetal exposures may impact offspring epigenetic signatures and adiposity. The authors hypothesized that maternal metabolic traits associate with cord blood DNA methylation, which, in turn, associates with child adiposity.

METHODS

Fasting serum was obtained in 588 pregnant women (27-34 weeks' gestation), and insulin, glucose, high-density lipoprotein cholesterol, triglycerides, and free fatty acids were measured. Cord blood DNA methylation and child adiposity were measured at birth, 4-6 months, and 4-6 years. The association of maternal metabolic traits with DNA methylation (429,246 CpGs) for differentially methylated probes (DMPs) and regions (DMRs) was tested. The association of the first principal component of each DMR with child adiposity was tested, and mediation analysis was performed.

RESULTS

Maternal triglycerides were associated with the most DMPs and DMRs of all traits tested (261 and 198, respectively, false discovery rate < 0.05). DMRs were near genes involved in immune function and lipid metabolism. Triglyceride-associated CpGs were associated with child adiposity at 4-6 months (32 CpGs) and 4-6 years (2 CpGs). One, near CD226, was observed at both timepoints, mediating 10% and 22% of the relationship between maternal triglycerides and child adiposity at 4-6 months and 4-6 years, respectively.

CONCLUSIONS

DNA methylation may play a role in the association of maternal triglycerides and child adiposity.

Maternal diet alters long-term innate immune cell memory in fetal and juvenile hematopoietic stem and progenitor cells in nonhuman primate offspring

Maternal overnutrition increases inflammatory and metabolic disease risk in postnatal offspring. This constitutes a major public health concern due to increasing prevalence of these diseases, yet mechanisms remain unclear. Here, using nonhuman primate models, we show that maternal Western-style diet (mWSD) exposure is associated with persistent pro-inflammatory phenotypes at the transcriptional, metabolic, and functional levels in bone marrow-derived macrophages (BMDMs) from 3-year-old juvenile offspring and in hematopoietic stem and progenitor cells (HSPCs) from fetal and juvenile bone marrow and fetal liver. mWSD exposure is also associated with increased oleic acid in fetal and juvenile bone marrow and fetal liver. Assay for transposase-accessible chromatin with sequencing (ATAC-seq) profiling of HSPCs and BMDMs from mWSD-exposed juveniles supports a model in which HSPCs transmit pro-inflammatory memory to myeloid cells beginning in utero. These findings show that maternal diet alters long-term immune cell developmental programming in HSPCs with proposed consequences for chronic diseases featuring altered immune/inflammatory activation across the lifespan.

Maternal obesity is associated with a higher number of regulatory-T-cells in newborns without affecting suppression

BACKGROUND

Maternal obesity (MO) is associated with a higher risk of immune-mediated diseases in the offspring and higher leptin levels in cord blood (CB). This study evaluates the number and function of lymphocyte subtypes in CB related to MO and its relationship with leptin concentration and leptin receptor expression.

METHODS

Pregnant women with (n = 32) or without obesity (n = 41) were enrolled at delivery. Cord blood mononuclear cells were separated with Ficoll-Hypaque. B and CD4+, regulatory and effector T cells were quantified by Flow Cytometry. Cord blood leptin concentration was measured by ELISA, and the leptin receptor (sLepR) on Treg cells was determined by Flow Cytometry.

RESULTS

MO was associated with higher numbers of CD4+, Treg and effector T cells in the CB of their offspring, without differences in the suppressive function of Tregs. Female offspring had a higher number of these cells and a higher cord leptin concentration. Tregs expressed higher levels of sLepR than effector T cells, without differences between groups.

CONCLUSIONS

MO is associated with changes in the newborn's immune profile, more evident in female newborns with higher leptin concentrations. More studies are needed to identify the mechanisms by which the high levels of cord leptin in the newborn of women with obesity could affect the offspring's immune system.

Maternal obesity blunts antimicrobial responses in fetal monocytes

Maternal pre-pregnancy (pregravid) obesity is associated with adverse outcomes for both mother and offspring. Amongst the complications for the offspring is increased susceptibility and severity of neonatal infections necessitating admission to the intensive care unit, notably bacterial sepsis and enterocolitis. Previous studies have reported aberrant responses to LPS and polyclonal stimulation by umbilical cord blood monocytes that were mediated by alterations in the epigenome. In this study, we show that pregravid obesity dysregulates umbilical cord blood monocyte responses to bacterial and viral pathogens. Specifically, interferon-stimulated gene expression and inflammatory responses to respiratory syncytial virus (RSV) and E. coli were significantly dampened, respectively . Although upstream signaling events were comparable, translocation of the key transcription factor NF-κB and chromatin accessibility at pro-inflammatory gene promoters following TLR stimulation was significantly attenuated. Using a rhesus macaque model of western style diet-induced obesity, we further demonstrate that this defect is detected in fetal peripheral monocytes and tissue-resident macrophages during gestation. Collectively, these data indicate that maternal obesity alters metabolic, signaling, and epigenetic profiles of fetal monocytes leading to a state of immune paralysis during late gestation and at birth.

Asthma, obesity, and microbiota: A complex immunological interaction

Obesity and allergic asthma are inflammatory chronic diseases mediated by distinct immunological features, obesity presents a Th1/Th17 profile, asthma is commonly associated with Th2 response. However, when combined, they result in more severe asthma symptoms, greater frequency of exacerbation episodes, and lower therapy responsiveness. These features lead to decreased life quality, associated with higher morbidity/mortality rates.  In addition, obesity prompts specific asthma phenotypes, which can be dependent on atopic status, age, and gender. In adults, obesity is associated with neutrophilic/Th17 profile, while in children, the outcome is diverse, in some cases children with obesity present aggravation of atopy, and Th2 inflammation, and in others an association with a Th1 profile, with reduced IgE levels and eosinophilia. These alterations occur due to a complex group of factors among which the microbiome has been recently explored. Particularly, evidence shows its important role in susceptibility or resistance to asthma development, via gut-lung-axis, and demonstrates its relevance to the immune pathogenesis of the syndrome. Few studies address the relevance of the lung microbiome in shaping the immune response, locally. However, specific bacteria, like Moraxella catarrhalis, Haemophilus influenza, and Streptococcus pneumoniae, correlate with important features of the obese-asthmatic phenotype. Although maternal obesity is known to increase asthma risk in offspring, the impact on lung colonization is unknown. This review details the main key immune mechanisms involved in obesity-aggravated asthma, featuring the effect of maternal obesity in the establishment of gut and lung microbiota of the offspring, acting as potential childhood asthma inducer.

SARS-CoV-2 Vaccine Booster Elicits Robust Prolonged Maternal Antibody Responses and Passive Transfer Via The Placenta And Breastmilk

Background

Infection during pregnancy can result in adverse outcomes for both pregnant persons and offspring. Maternal vaccination is an effective mechanism to protect both mother and neonate into post-partum. However, our understanding of passive transfer of antibodies elicited by maternal SARS-CoV-2 mRNA vaccination during pregnancy remains incomplete.

Objective

We aimed to evaluate the antibody responses engendered by maternal SARS-CoV-2 vaccination following initial and booster doses in maternal circulation and breastmilk to better understand passive immunization of the newborn.

Study Design

We collected longitudinal blood samples from 121 pregnant women who received SARS-CoV-2 mRNA vaccines spanning from early gestation to delivery followed by collection of blood samples and breastmilk between delivery and 12 months post-partum. During the study, 70% of the participants also received a booster post-partum. Paired maternal plasma, breastmilk, umbilical cord plasma, and newborn plasma samples were tested via enzyme-linked immunosorbent assays (ELISA) to evaluate SARS-CoV-2 specific IgG antibody levels.

Results

Vaccine-elicited maternal antibodies were detected in both cord blood and newborn blood, albeit at lower levels than maternal circulation, demonstrating transplacental passive immunization. Booster vaccination significantly increased spike specific IgG antibody titers in maternal plasma and breastmilk. Finally, SARS-CoV-2 specific IgG antibodies in newborn blood correlated negatively with days post initial maternal vaccine dose.

Conclusion

Vaccine-induced maternal SARS-CoV-2 antibodies were passively transferred to the offspring in utero via the placenta and after birth via breastfeeding. Maternal booster vaccination, regardless of gestational age at maternal vaccination, significantly increased antibody levels in breastmilk and maternal plasma, indicating the importance of this additional dose to maximize passive protection against SARS-CoV-2 infection for neonates and infants until vaccination eligibility.

Identification of two potential immune-related biomarkers of Graves' disease based on integrated bioinformatics analyses

BACKGROUND

Graves' disease (GD) is an autoimmune disease, the incidence of which is increasing yearly. GD requires long-life therapy. Therefore, the potential immune-related biomarkers of GD need to be studied.

METHOD

In our study, differentially expressed genes (DEGs) were derived from the online Gene Expression Omnibus (GEO) microarray expression dataset GSE71956. Protein‒protein interaction (PPI) network analyses were used to identify hub genes, which were validated by qPCR. GSEA was used to screen potential pathways and related immune cells. Next, CIBERSORT analysis was used to further explore the immune subtype distribution pattern among hub genes. ROC curves were used to analyze the specificity and sensitivity of hub genes.

RESULT

44 DEGs were screened from the GEO dataset. Two hub genes, EEF1A1 and EIF4B, were obtained from the PPI network and validated by qPCR (p < 0.05). GSEA was conducted to identify potential pathways and immune cells related to these the two hub genes. Immune cell subtype analysis revealed that hub genes had extensive associations with many different types of immune cells, particularly resting memory CD4⁺ T cells. AUCs of ROC analysis were 0.687 and 0.733 for EEF1A1 and EIF4B, respectively.

CONCLUSION

Our study revealed two hub genes, EEF1A1 and EIF4B, that are associated with resting memory CD4⁺ T cells and potential immune-related molecular biomarkers and therapeutic targets of GD.

Maternal obesity and the impact of associated early-life inflammation on long-term health of offspring

The prevalence of obesity is increasingly common in the United States, with ~25% of women of reproductive age being overweight or obese. Metaflammation, a chronic low grade inflammatory state caused by altered metabolism, is often present in pregnancies complicated by obesity. As a result, the fetuses of mothers who are obese are exposed to an in-utero environment that has altered nutrients and cytokines. Notably, both human and preclinical studies have shown that children born to mothers with obesity have higher risks of developing chronic illnesses affecting various organ systems. In this review, the authors sought to present the role of cytokines and inflammation during healthy pregnancy and determine how maternal obesity changes the inflammatory landscape of the mother, leading to fetal reprogramming. Next, the negative long-term impact on offspring’s health in numerous disease contexts, including offspring’s risk of developing neuropsychiatric disorders (autism, attention deficit and hyperactive disorder), metabolic diseases (obesity, type 2 diabetes), atopy, and malignancies will be discussed along with the potential of altered immune/inflammatory status in offspring as a contributor of these diseases. Finally, the authors will list critical knowledge gaps in the field of developmental programming of health and diseases in the context of offspring of mothers with obesity, particularly the understudied role of hematopoietic stem and progenitor cells.

Maternal obesity and acute lymphoblastic leukemia risk in offspring: A summary of trends, epidemiological evidence, and possible biological mechanisms

Acute lymphoblastic leukemia, a heterogenous malignancy characterized by uncontrolled proliferation of lymphoid progenitors and generally initiated in utero, is the most common pediatric cancer. Although incidence of ALL has been steadily increasing in recent decades, no clear reason for this trend has been identified. Rising concurrently with ALL incidence, increasing maternal obesity rates may be partially contributing to increasing ALL prevelance. Epidemiological studies, including a recent meta-analysis, have found an association between maternal obesity and leukemogenesis in offspring, although mechanisms underlying this association remain unknown. Therefore, the purpose of this review is to propose possible mechanisms connecting maternal obesity to ALL risk in offspring, including changes to fetal/neonatal epigenetics, altered insulin-like growth factor profiles and insulin resistance, modified adipokine production and secretion, changes to immune cell populations, and impacts on birthweight and childhood obesity/adiposity. We describe how each proposed mechanism is biologically plausible due to their connection with maternal obesity, presence in neonatal and/or fetal tissue, observation in pediatric ALL patients at diagnosis, and association with leukemogenesis, A description of ALL and maternal obesity trends, a summary of epidemiological evidence, a discussion of the pathway from intrauterine environment to subsequent malignancy, and propositions for future directions are also presented.

Maternal prenatal depressive symptoms and toddler behavior: an umbilical cord blood epigenome-wide association study

Children of mothers with prenatal depressive symptoms (PND) have a higher risk of behavioral problems; fetal programming through DNA methylation is a possible underlying mechanism. This study investigated DNA methylation in cord blood to identify possible "at birth" signatures that may indicate susceptibility to behavioral problems at 18 months of age. Cord blood was collected from 256 children of mothers who had self-reported on symptoms of depression during pregnancy and the behavior of their child at 18 months of age. Whole genome DNA methylation was assessed using Illumina MethylationEPIC assay. The mother and child pairs were categorized into four groups, based on both self-reported depressive symptoms, PND or Healthy control (HC), and scores from the Child Behavior checklist (high or low for internalizing, externalizing, and total scores). Adjustments were made for batch effects, cell-type, and clinical covariates. Differentially methylated sites were identified using Kruskal-Wallis test, and Benjamini-Hochberg adjusted p values < 0.05 were considered significant. The analysis was also stratified by sex of the child. Among boys, we observed higher and correlated DNA methylation of one CpG-site in the promoter region of TPP1 in the HC group, with high externalizing scores compared to HC with low externalizing scores. Boys in the PND group showed lower DNA methylation in NUDT15 among those with high, compared to low, internalizing scores; the DNA methylation levels of CpGs in this gene were positively correlated with the CBCL scores. Hence, the differentially methylated CpG sites could be of interest for resilience, regardless of maternal mental health during pregnancy. The findings are in a relatively healthy study cohort, thus limiting the possibility of detecting strong effects associated with behavioral difficulties. This is the first investigation of cord blood DNA methylation signs of fetal programming of PND on child behavior at 18 months of age and thus calls for independent replications.

Immune cell profile and immune-related gene expression of obese peripheral blood and liver tissue

Obesity is associated with changes in immune cell subpopulations. However, tissue and blood obesity-responsive immune phenotypic pathways have not been contrasted. Here, the local niche immune cell population and gene expression in fatty liver is compared to peripheral blood of obese individuals. The Cibersort algorithm enumerated increased fractions of memory CD4+ T lymphocytes and reductions in natural killer and memory B cells in obese liver tissue and obese blood, with similar reductions found in nonalcoholic fatty liver disease tissue. Gene expression analysis identified inflammatory immune signatures of regulatory CD4+ T cells with inferred Th1, Th17, Th2, or Treg phenotypes that differed between liver and blood. Our study suggests that the local tissue-specific immune phenotype in the liver differs from the obese peripheral circulation, with the latter reflective of multisystemic persistent inflammation that is characteristic of obesity.