Neonatal Mononuclear Cells Research Articles

Single-Cell RNA Sequencing Reveals That Breastfeeding Shapes IL-4 and IL-13 Signaling in Neonatal Peripheral Blood Mononuclear Cells

Single-Cell RNA Sequencing Reveals That Breastfeeding Shapes IL-4 and IL-13 Signaling in Neonatal Peripheral Blood Mononuclear Cells

A history of childhood maltreatment is associated with altered DNA methylation levels of DNA methyltransferase 1 in maternal but not neonatal mononuclear immune cells.

Childhood maltreatment (CM) is associated with alterations in DNA methylation (DNAm) especially in stress response genes. Due to the higher risk of overall health complications of individuals with a parental history of CM, intergenerational transmission of CM-associated DNAm changes has been investigated but remains unclear. In this study, we investigated if different severities of CM have any influence on the DNAm of DNA methyltransferase 1 (DNMT1), an important enzyme of the DNAm machinery, in immune and buccal cells of mother-newborn dyads. DNAm was assessed by mass spectrometry using immune cell DNA from mothers (N = 117) and their newborns (N = 113), and buccal cell DNA of mother-newborn dyads (N = 68 each). Mothers with a history of CM had lower mean methylation of DNMT1 in immune cells compared to the mothers without a CM history. CM status only influenced maternal DNMT1 gene expression when at least moderate CM was reported. Buccal cell DNAm was not associated with CM status. Maternal history of CM was not linked to any alterations in DNMT1 mean DNAm in any of the cell types studied in newborns. We conclude that the CM-associated alterations in DNMT1 DNAm might point to allostatic load and can be physiologically relevant, especially in individuals with more severe CM experiences, resulting in an activated DNA methylation machinery that might influence stress response genes. Our lack of significant findings in buccal cells shows the tissue-specific effects of CM on DNAm. In our sample with low to moderate maternal CM history, there was no intergenerational transmission of DNMT1 DNAm in newborns.

Group B streptococci infection model shows decreased regulatory capacity of cord blood cells

BackgroundSepsis is one of the leading causes of morbidity and mortality in the neonatal period. Compared to adults, neonates are more susceptible to infections, especially to systemic infections with Group B Streptococcus (GBS). Furthermore, neonates show defects in terminating inflammation. The immunological causes for the increased susceptibility to infection and the prolonged inflammatory response are still incompletely understood.MethodsIn the present study, we aimed to investigate the reaction of cord blood mononuclear cells (MNC) to stimulation with GBS in comparison to that of MNC from adult blood with focus on the proliferative response in an in vitro infection model with heat-inactivated GBS.ResultsWe demonstrate that after stimulation with GBS the proliferation of T cells from adult blood strongly decreased, while the proliferation of cord blood T cells remained unchanged. This effect could be traced back to a transformation of adult monocytes, but not cord blood monocytes, to a suppressive phenotype with increased expression of the co-inhibitory molecule programmed death ligand 1 (PD-L1).ConclusionsThese results point towards an increased inflammatory capacity of neonatal MNC after stimulation with GBS. Targeting the prolonged inflammatory response of neonatal immune cells may be a strategy to prevent complications of neonatal infections.ImpactNeonatal sepsis often leads to post-inflammatory complications.Causes for sustained inflammation in neonates are incompletely understood.We show that cord blood T cells exhibited increased proliferative capacity after stimulation with group B streptococci (GBS) in comparison to adult T cells.Adult monocytes but not cord blood monocytes acquired suppressive activity and expressed increased levels of PD-L1 after GBS stimulation.Increased proliferative capacity of neonatal T cells and decreased suppressive activity of neonatal monocytes during GBS infection may contribute to prolonged inflammation and development of post-inflammatory diseases in newborns.

Childhood maltreatment is associated with changes in mitochondrial bioenergetics in maternal, but not in neonatal immune cells

Childhood maltreatment (CM) comprises experiences of abuse and neglect during childhood. CM causes psychological as well as biological alterations in affected individuals. In humans, it is hardly explored whether these CM consequences can be transmitted directly on a biological level to the next generation. Here, we investigated the associations between maternal CM and mitochondrial bioenergetics (mitochondrial respiration and intracellular mitochondrial density) in immune cells of mothers and compared them with those of their newborns. In n = 102 healthy mother-newborn dyads, maternal peripheral blood mononuclear cells and neonatal umbilical cord blood mononuclear cells were collected and cryopreserved shortly after parturition to measure mitochondrial respiration and intracellular mitochondrial density with high-resolution respirometry and spectrophotometric analyses, respectively. Maternal CM was assessed with the Childhood Trauma Questionnaire Maternal and neonatal mitochondrial bioenergetics were quantitatively comparable and positively correlated. Female newborns showed higher mitochondrial respiration compared to male newborns. Maternal CM load was significantly and positively associated with mitochondrial respiration and density in mothers, but not with mitochondrial respiration in newborns. Although maternal and neonatal mitochondrial bioenergetics were positively correlated, maternal CM only had a small effect on mitochondrial density in newborns, which was not significant in this study after adjustment for multiple comparisons. The biological relevance of our finding and its consequences for child development need further investigation in future larger studies. This study reports data on mitochondrial bioenergetics of healthy mother-newborn dyads with varying degrees of CM.

Mitochondrial implications in human pregnancies with intrauterine growth restriction and associated cardiac remodelling.

Intrauterine growth restriction (IUGR) is an obstetric complication characterised by placental insufficiency and secondary cardiovascular remodelling that can lead to cardiomyopathy in adulthood. Despite its aetiology and potential therapeutics are poorly understood, bioenergetic deficits have been demonstrated in adverse foetal and cardiac development. We aimed to evaluate the role of mitochondria in human pregnancies with IUGR. In a single‐site, cross‐sectional and observational study, we included placenta and maternal peripheral and neonatal cord blood mononuclear cells (PBMC and CBMC) from 14 IUGR and 22 control pregnancies. The following mitochondrial measurements were assessed: enzymatic activities of mitochondrial respiratory chain (MRC) complexes I, II, IV, I + III and II + III, oxygen consumption (cell and complex I‐stimulated respiration), mitochondrial content (citrate synthase [CS] activity and mitochondrial DNA copy number), total ATP levels and lipid peroxidation. Sirtuin3 expression was evaluated as a potential regulator of bioenergetic imbalance. Intrauterine growth restriction placental tissue showed a significant decrease of MRC CI enzymatic activity (P < 0.05) and CI‐stimulated oxygen consumption (P < 0.05) accompanied by a significant increase of Sirtuin3/β‐actin protein levels (P < 0.05). Maternal PBMC and neonatal CBMC from IUGR patients presented a not significant decrease in oxygen consumption (cell and CI‐stimulated respiration) and MRC enzymatic activities (CII and CIV). Moreover, CS activity was significantly reduced in IUGR new‐borns (P < 0.05). Total ATP levels and lipid peroxidation were preserved in all the studied tissues. Altered mitochondrial function of IUGR is especially present at placental and neonatal level, conveying potential targets to modulate obstetric outcome through dietary interventions aimed to regulate Sirtuin3 function.

Effect of betamethasone, indomethacin and fenoterol on neonatal and maternal mononuclear cells stimulated with Escherichia coli

Despite considerable progress in the field of perinatal care, infectious diseases, especially when caused by gram negative bacteria, remain a major reason for neonatal morbidity and mortality. Notably infants born prematurely and those with very low birth weight are at risk due to their immature and deficient immune system and their prolonged hospitalization which promotes nosocomial infections. In case of impending preterm birth, betamethasone is given to induce lung maturation and tocolytic agents like indomethacin or fenoterol are administered to suppress premature labor. The aim of this study was to analyze the effects of these drugs on the immune system of mothers and neonates. Therefore, mononuclear cells from cord blood and peripheral maternal blood were stimulated with Escherichia coli and incubated with betamethasone, indomethacin and fenoterol. Subsequently the effect of the treatment on cytokine production was determined. Betamethasone alone and in combination with tocolytic agents inhibited the production of pro- and anti-inflammatory cytokines. Not only does betamethasone dampen the immune response by reducing the production of cytokines, it also has a variety of other detrimental short- and long-term effects on the neonate. In conclusion we would recommend using biological markers to determine if premature labor actually leads to preterm birth and subsequently administer betamethasone only to mothers giving birth prematurely.

Neonatal porcine blood derived dendritic cell subsets show activation after TLR2 or TLR9 stimulation

The present study investigated the innate immune response in vitro to determine porcine neonate responses with Toll-like receptor (TLR)2 ligand (Pam3Cys) or TLR9 ligand (CpG) and compared these with adults. We identified the same phenotypically defined dendritic cell (DC) subsets and DC proportions in porcine neonate and adult blood by flow cytometry, which were plasmacytoid DCs (pDCs): CD14−CD4+CD172a+CADM1-) and conventional DCs (cDCs), being further divided into a cDC1 (CD14−CD4−CD172alowCADM1+) and a cDC2 (CD14−CD4−CD172a+CADM1+) subset. With neonatal cells, the TLR2 ligand induced a stronger TNF expression in monocytes and pDCs, and a stronger CD80/86 upregulation in cDC1, when compared to adult cells. Furthermore, in neonatal mononuclear cells TLR9 ligand was more potent at inducing IL12p40 mRNA expression. These results indicate clear responses of porcine neonatal antigen presenting cells after TLR2 and TLR9 stimulation, suggesting that corresponding ligands could be promising candidates for neonatal adjuvant application.

Imbalance in mitochondrial dynamics and apoptosis in pregnancies among HIV-infected women on HAART with obstetric complications.

HIV infection and HAART trigger genetic and functional mitochondrial alterations leading to cell death and adverse clinical manifestations. Mitochondrial dynamics enable mitochondrial turnover and degradation of damaged mitochondria, which may lead to apoptosis. To evaluate markers of mitochondrial dynamics and apoptosis in pregnancies among HIV-infected women on HAART and determine their potential association with obstetric complications. This controlled, single-site, observational study without intervention included 26 HIV-infected pregnant women on HAART and 18 control pregnancies and their newborns. Maternal PBMCs and neonatal cord blood mononuclear cells (CBMCs) were isolated at the first trimester of gestation and at delivery. The placenta was homogenized at 5% w/v. Mitochondrial dynamics, fusion events [mitofusin 2 (Mfn2)/β-actin] and fission events [dynamin-related protein 1 (Drp1/β-actin)] and apoptosis (caspase3/β-actin) were assessed by western blot analysis. Obstetric complications were significantly more frequent in pregnancies among HIV-infected women [OR 5.00 (95% CI 1.21-20.70)]. Mfn2/β-actin levels in PBMCs from controls significantly decreased during pregnancy (202.13 ± 57.45%), whereas cases maintained reduced levels from the first trimester of pregnancy and no differences were observed in CBMCs. Mfn2/β-actin and Drp1/β-actin contents significantly decreased in the placenta of cases. Caspase3/β-actin levels significantly increased during pregnancy in PBMCs of cases (50.00 ± 7.89%), remaining significantly higher than in controls. No significant differences in caspase 3/β-actin content of neonatal CBMCs were observed, but there was a slight increased trend in placenta from cases. HIV- and HAART-mediated mitochondrial damage may be enhanced by decreased mitochondrial dynamics and increased apoptosis in maternal and placental compartments but not in the uninfected fetus. However, direct effects on mitochondrial dynamics and implication of apoptosis were not demonstrated in adverse obstetric outcomes.

Intracellular DNA sensing pathway of cGAS-cGAMP is decreased in human newborns and young children

Newborns are highly susceptible to DNA virus infections, which may result from the characteristics of neonatal innate immune systems. Here we analyzed for the first time the development of innate immune sensing and signaling of intracellular DNA virus infection in human newborns and young children. Both mRNA and protein expression of cGAS, an intracellular DNA sensor, were shown to be significantly reduced in neonatal peripheral blood mononuclear cells (PBMCs). In addition, cGAS expression in neonatal PBMCs could be induced upon herpes simplex virus type 1 (HSV-1) or interferon-α (IFNα) stimulation. Furthermore, production of the second messenger cGAMP and activation of the transcriptional factor IRF3 was severely decreased in neonatal cord blood mononuclear cells (CBMCs) or PBMCs compared with adults. In contrast, the downstream signaling STING-TBK1-IRF3 appeared to be functional in neonatal PBMCs, as demonstrated by the fact that IRF3 phosphorylation and IFNβ production in these cells could be activated by cGAMP. Intriguingly, decreased expression of cGAS in neonatal cells can be rescued by DNA demethylation, with concomitant enhancement in IFNβ induction by HSV-1. Thus, cGAS restoration or STING stimulation by small molecules during infancy might improve the age-dependent susceptibility to DNA virus infection.

The expression and function of human CD300 receptors on blood circulating mononuclear cells are distinct in neonates and adults.

Neonates are more susceptible to infections than adults. This susceptibility is thought to reflect neonates’ qualitative and quantitative defects in the adaptive and innate immune responses. Differential expression of cell surface receptors may result in altered thresholds of neonatal immune cell activation. We determined whether the expression and function of the lipid-binding CD300 family of receptors are different on neonatal immune cells compared to adult immune cells. A multiparametric flow cytometry analysis was performed to determine the expression of CD300 receptors on adult peripheral blood mononuclear cells and neonatal cord blood mononuclear cells. The expression of the CD300a inhibitory receptor was significantly reduced on cells from the newborn adaptive immune system, and neonatal antigen presenting cells exhibited a different CD300 receptors expression pattern. We also found differential LPS-mediated regulation of CD300 receptors expression on adult monocytes compared to cord blood monocytes, and that CD300c and CD300e-mediated activation was quantitatively different in neonatal monocytes. This is the first complete study examining the expression of CD300 receptors on human neonatal immune cells compared with adult immune cells. Significant differences in the expression and function of CD300 receptors may help to explain the peculiarities and distinctness of the neonatal immune responses.

Effects of Fetal and Neonatal Murine Peripheral Blood Mononuclear Cells Infusion on MicroRNA-145 Expression in Renal Vascular Smooth Muscle Cells in MRL/lpr Mice

For patients with refractory systemic lupus erythematosus, current medications are insufficient to control their condition, and new treatments are necessary. We aimed to evaluate the therapeutic effect of fetal and neonatal murine peripheral blood (FNPB) mononuclear cells and their impact on microRNA-145 (miR-145) in renal vascular smooth muscle cells (VSMCs) of MRL/lpr lupus-prone mice. MRL/lpr mice aged 20 weeks were randomized to 3 groups of 15 (control group, radiation group, infusion group). The renal tissues were subjected to pathological examination. In situ hybridization assay was applied to measure miR-145 expression in renal vessels of MRL/lpr mice. The infusion group had significantly better results for pathological renal tissue lesions than either the control or radiation group. In MRL/lpr mice, there was positive expression of miR-145 in renal VSMCs, although the expression of miR-145 was not discernible in renal vascular intima and adventitia. The miR-145 expression in renal VSMCs in the infusion group was significantly higher than in the control or radiation group, and higher in the radiation group than in the control group; however, the difference was not statistically significant. The increased expression of miR-145 in renal VSMCs might be one of the mechanisms supporting FNPB as a therapy for lupus nephritis; it also suggests that the miR-145 in renal vessels might be a new target for treatment of lupus nephritis.

The effect of Indomethacin and Betamethasone on the cytokine response of human neonatal mononuclear cells to gram-positive bacteria

Intrauterine infections with gram-positive bacteria pose a serious threat to neonates since they can result in neonatal sepsis, induce a fetal inflammatory response and also cause preterm birth. Despite intensive care, prematurity remains a leading cause of neonatal death, and is often accompanied by a number of morbidities. In order to prevent premature birth, tocolytic agents like Indomethacin are administered. Betamethasone is used to promote lung maturation and prevent respiratory distress syndrome. A combination of both drugs is assumed to prevent premature delivery while simultaneously facilitating lung maturation. This study investigates the effect of Betamethasone, Indomethacin and a combination of both on the cytokine production of neonatal cord blood mononuclear cells (CBMC) after stimulation with lysates of the gram-positive pathogens Streptococcus agalactiae and Enterococcus faecalis. The aim of the study is to determine the impact of these drugs on the function of the neonatal immune system which should aid clinicians in choosing the optimal therapy in case of preterm birth associated with intrauterine infection. Betamethasone reduced the production of the pro-inflammatory cytokines IL-6, IL-12p40, MIP-1α and TNF and increased the expression of the anti-inflammatory cytokine IL-10, depending on the pathogen used for stimulation. In contrast to Betamethasone, Indomethacin almost exclusively increased IL-10 production. The combination of both drugs decreased the expression of IL-6, IL-12p40, MIP-1α and TNF while increasing IL-10 production, depending on the concentration of Indomethacin and the pathogen used for stimulation. Based on our results, the combination therapy with Indomethacin and Betamethasone has a similar effect on cytokine production as Betamethasone alone, which is generally administered in case of impending preterm birth. However, the combination therapy has the advantage of promoting lung maturation while simultaneously blocking preterm labor effectively.

Effect of nonmyeloablative unrelated fetal and neonatal murine peripheral blood mononuclear cell infusion on MRL/lpr mice.

For patients with refractory systemic lupus erythematosus (SLE), current medications are insufficient to control their condition, and new treatments are necessary. We investigated the effect of fetal and neonatal murine peripheral blood (FNPB) mononuclear cells on MRL/lpr lupus-prone mice. Female MRL/lpr mice were randomized to three groups (control, radiation and infusion groups). The infusion group had significantly better results for survival rate, body weight increase, reduction of spleen index, serum anti-ds-DNA antibody, antinuclear antibodies (ANA) and creatinine (Cr), 24 h urine protein and pathological renal tissue lesions than either the control or radiation group. Graft versus host disease (GVHD) was not observed in MRL/lpr mice in the infusion group. The infusion group also had better hematogenesis reconstruction than the radiation group. Flow cytometry analysis revealed a significant increase in Th1, CD8+ T and T reg cells and a reduction in Th2, CD4+ T and Th17 cells in the peripheral blood of the radiation and infusion groups compared with the control group. Immunocytochemical assay revealed a significant increase in serum transforming growth factor (TGF)-β and a significant reduction in interleukin (IL)-17 in the radiation and infusion groups compared with the control group. Therefore, our study showed that FNPB mononuclear cell infusion has a significant role in regulating CD4+ T cells, Th1/Th2, Th17/T reg balance and their corresponding cytokines in MRL/lpr mice. The FNPB mononuclear cell infusion provided evidence in animals and suggested a potential clinical application for umbilical cord blood transplantation to treat SLE patients.

Complex Effects of Vitamin E and Vitamin C Supplementation on in Vitro Neonatal Mononuclear Cell Responses to Allergens

Low maternal dietary vitamin E (but not vitamin C) intake during pregnancy has been associated with increased in vitro cord blood mononuclear cell (CBMC) proliferative responses, childhood wheezing and asthma. We investigated whether these associations reflect direct effects of vitamin E by investigating the effects of supplementing CBMC cultures with physiological concentrations of vitamin E. CBMC from seventy neonates were cultured supplemented with either nothing, α-tocopherol or ascorbic acid. Proliferative, IFN-γ, IL-4, IL-10 and TGF-β responses were measured. In general, vitamin E supplementation was associated with a trend for reduced proliferative responses after stimulation with antigens and house dust mite, and with increased proliferation after stimulation with timothy grass allergen. There was a trend for CBMC cultures to exhibit decreased secretion of IFN-γ, IL-10 and IL-4. Supplementation with vitamin C had no effect on CBMC proliferation, but increased IFN-γ and IL-4 production, and decreased IL-10 production. In conclusion, in vitro vitamin E and C supplementation of CBMC modifies neonatal immune function, but not in a manner predicted by observational epidemiological studies. The observed associations between vitamin E and childhood respiratory disease are complex, and the nature and form of nutritional intervention need to be carefully considered before inclusion in trials.

Maturation of Toll-like receptor 1–4 responsiveness during early life

BackgroundToll-like receptors (TLRs) are part of the highly conserved components of the innate immune system, and have been investigated extensively; however, little is known about TLR function during early postnatal life, a critical period for immune maturation. AimsIn order to achieve a more complete understanding of the ontogeny of immune system during the first years of life, our study investigated age-matched TLR1–4 responsiveness at several time points up to the age of two years. Study designMononuclear cells were isolated from cord blood (n=150) and peripheral blood from infants at 6 (n=68), 12 (n=75), and 24 (n=74)months of age, and from 50 adults. Cells were stimulated with Toll-like receptor ligands (TLR1–4) and phytohemagglutinin (PHA). Stimulated cells were assessed for their production of the cytokines tumor necrosis factor alpha (TNF-α) and interleukin-6 (IL-6), and for TLR4 gene expression. ResultsOur results suggested that cord response of IL-6 and TNF-α was not affected by allergic background. In addition, neonatal mononuclear cell had enhanced IL-6 production upon TLR1, 2, and 4 stimulations as compared to those of young children and adults. Nevertheless, after 6months of age, the level remained comparable throughout the first two years of life. While TNF-α response to all TLR stimulations remained fairly similar during early life. This cytokine pattern closely paralleled our findings for TLR4 mRNA expression, and longitudinal cytokine changes within the same individual. ConclusionsOur findings provided additional information to the understanding of immune development during early life, and offered stronger evidence of neonatal innate immunity being capable of responding adequately to TLR stimulation.

Opioids and clonidine modulate cytokine production and opioid receptor expression in neonatal immune cells

ObjectiveOpioids and clonidine, used in for sedation, analgesia and control of opioid withdrawal in neonates, directly or indirectly activate opioid receptors expressed in immune cells. Therefore, our objective is to study how clinically relevant concentrations of different opioids and clonidine change cytokine levels in cultured whole blood from preterm and full-term infants.Study designUsing blood from preterm (≤ 30 weeks gestational age, n=7) and full-term (≥37 weeks GA, n=19) infants, we investigated the changes in cytokine profile (IL-1β, IL-6, IL-8, IL-10, IL-12p70, and TNF-α), cyclic adenosine monophosphate (cAMP) levels and μ-, δ-, and κ- opioid receptor (OPR) gene and protein expression following in-vitro exposure to morphine, methadone, fentanyl, or clonidine at increasing concentrations ranging from 0 to 1 mM.ResultsFollowing LPS activation, IL-10 levels were 146-fold greater in cultured blood from full-term than from preterm infants. Morphine and methadone, but not fentanyl, at >10-5M decreased all tested cytokines except IL-8. In contrast, clonidine at <10-9M increased IL-6, while at >10-5M increased IL-1β and decreased TNF-α levels. All cytokine changes followed the same patterns in preterm and full-term infant cultured blood and matched increases in cAMP levels. All three μ-, δ- and κ-OPR genes were expressed in mononuclear cells from preterm and full-term infants. Morphine, methadone and clonidine, but not fentanyl, at >10-5M decreased the expression of μ-OPR, but not δ- or κ-OPRs.ConclusionGeneralized cytokine suppression along with downregulation of μ-OPR expression observed in neonatal mononuclear cells exposed to morphine and methadone at clinically relevant concentrations contrast with the modest effects observed with fentanyl and clonidine. Therefore, we speculate that fentanyl and clonidine may be safer therapeutic choices for sedation and control of opioid withdrawal and pain in neonates.

A novel role for interleukin‐1 receptor signaling in the developmental regulation of immune responses to endotoxin

Neonatal Innate immunity is distinct compared with later ages with some inflammatory cytokines produced in excess of adult levels in response to microbial products such as lipopolysaccharide (LPS). The molecular mechanisms underpinning this specific pattern of neonatal immunity are unknown. In this study, we compared gene expression and cytokine production from LPS stimulated mononuclear cell cultures from 60 individuals at birth and at 12-months. Neonatal mononuclear cell responses were characterized by high levels of IL-1β, IL-10, and IFNγ compared with mononuclear cell responses at 12 months. Microarray analysis of gene expression revealed widespread differences between the neonatal versus infant LPS response. We found expression of a subset of interleukin-1 receptor/Toll-like receptor (IL-1R/TLR) signaling genes was highly expressed in the neonatal period and rapidly down regulated by 12 months. The data suggest that IL-1R1 expression in the neonatal period provides an additional level of Myd88-dependent signaling during this period of heighted susceptibility to infection.

Erratum: Identification of immunodeficient molecules in neonatal mononuclear cells by proteomic differential displays

Hong-Ren Yu1*, Hsing-Chun Kuo2,3*, Hsin-Chun Huang1, Ho-Chang Kuo1, Tai-Yuan Chen4, Li-Tung Huang1, You-Lin Tain1, Chih-Cheng Chen1, Jiunn-Ming Sheen1, I-Chun Lin1, Chia-Yo Ou5, Te-Yao Hsu5, Yi-Jyun Jheng1 and Kuender D. Yang1 1 Department of Pediatrics, Kaohsiung Chang Gung Memorial Hospital, Graduate Institute of Clinical Medical Sciences, Chang Gung University College of Medicine, Taiwan 2 Department of Nursing, Chiayi Campus, Chang Gung University of Science and Technology, Taiwan 3 Chronic Diseases and Health Promotion Research Center, CGUST, Taiwan 4 Department of Food Science, National Taiwan Ocean University, Taiwan 5 Department of Obstetrics, Kaohsiung Chang Gung Memorial Hospital, Graduate Institute of Clinical Medical Sciences, Chang Gung University College of Medicine, Taiwan

Evidence for age-related and individual-specific changes in DNA methylation profile of mononuclear cells during early immune development in humans

Environment induced epigenetic effects on gene expression in early life are likely to play important roles in mediating the risk of several immune-related diseases. In order to investigate this fully, it is essential to first document temporal changes in epigenetic profile in disease-free individuals as a prelude to defining environmentally mediated changes. Mononuclear cells (MC) were collected longitudinally from a small number of females at birth, 1 year, 2.5 years and 5 years of age and examined for changes in genome-scale DNA methylation profiles using the Illumina Infinium HumanMethylation27 BeadChip array platform. MC from two males were included for comparative purposes. Flow cytometry was used to define MC cell populations in each sample in order to exclude this as the major driver of epigenetic change. The data underwent quality control and normalization within the R programming environment. Unsupervised hierarchical clustering of samples clearly delineated neonatal MC from all other ages. A further clear distinction was observed between 1 year and 5 year samples, with 2.5 year samples showing a mixed distribution between the 1 and 5 year groups. Gene ontology of probes significantly variable over the neonatal period revealed methylation changes in genes associated with cell surface receptor and signal transduction events. In the postnatal period, methylation changes were mostly associated with the development of effector immune responses and homeostasis. Unlike all other chromosomes tested, a predominantly genetic effect was identified as controlling maintenance of X-chromosome methylation profile in females, largely refractory to change over time. This data suggests that the primary driver of neonatal epigenome is determined in utero, whilst postnatally, multiple genetic and environmental factors are implicated in the development of MC epigenetic profile, particularly between the ages of 1–5 years, when the highest level of inter individual variation is apparent. This supports a model for differential sensitivity of specific individuals to disruption in the developing epigenome during the first years of life. Further studies are now needed to examine evolving epigenetic variations in specific cell populations in relation to environmental exposures, immune phenotype and subsequent disease susceptibility.

Identification of immunodeficient molecules in neonatal mononuclear cells by proteomic differential displays

Human newborns are known to be susceptible to microbial infection. This susceptibility is generally attributed to immaturity of the newborn immune system. However, the mechanisms for impaired immunity in newborns are still incompletely defined. In this study, we sought to elucidate the protein differential display between adult and neonatal mononuclear cells (MNC) using a proteomic approach. MNC samples from cord blood and adult peripheral blood were subjected to 2-D PAGE analysis. Differential protein displays between cord blood and adult MNC were determined and validated. There were 34 differentially expressed proteins between cord blood and adult MNC identified by 2-D PAGE. The differentially displayed proteins were clustered into two major signal pathways, cellular processing and purine metabolism. After validation by Western blot, we found more abundant arginase-1 (ARG1) and Rho GDP-dissociation inhibitor 2 (RhoGDI2), while less adenosine deaminase (ADA) and β-actin in cord blood MNC. In functional validation, we found that lower ADA was proven to enhance the TNF-α production by cord blood monocytes. The results from this study discovered the proteomic displays for altered immunity between adult and neonatal MNC that support a understanding of the correction of impaired immune response in newborns.