Epigenome-wide analysis of maternal exposure to green space during gestation and cord blood DNA methylation in the ENVIRONAGE cohort

Maternal perceived stress and green spaces during pregnancy are associated with adult offspring gene (NR3C1 and IGF2/H19) methylation patterns in adulthood: A pilot study

BACKGROUND

Changes in NR3C1 and IGF2/H19 methylation patterns have been associated with behavioural and psychiatric outcomes. Maternal mental state has been associated with offspring NR3C1 promotor and IGF2/H19 imprinting control region (ICR) methylation patterns. However, there is a lack of prospective studies with long-term follow-up.

METHODS

52 mother-offspring pairs were studied from 12 to 22 weeks of pregnancy and offspring was followed-up until 28-29 years-of-age. During pregnancy, mothers filled in a Life Event Scale and a Daily Hassles Scale measuring perceived stress; i.e., appraisal or subjectively experienced severity of impact of important life events and of daily hassles in several life domains during pregnancy, respectively. Green space was quantified around the residence, using high-resolution (1 m2) map data. Saliva and blood samples were obtained from the adult offspring. Absolute DNA methylation levels were determined in blood and saliva on four NR3C1 amplicons, and one IGF2/H19 ICR amplicon using a bisulfite PCR and sequencing method. Linear mixed effect models were used to test the associations between perceived stress and green spaces during pregnancy, and adult offspring methylation patterns.

RESULTS

We found associations between maternal perceived stress during pregnancy and methylation patterns on two out of the four NR3C1 amplicons, measured in blood, from offspring in adulthood, but not with IGF2/H19 methylation. For an interquartile-range (IQR) increase in maternal perceived life event or daily hassles stress scores, absolute methylation levels on several NR3C1 CpG sites were significantly changed (-1.62 % to +5.89 %, p<0.05). Maternal perceived stress scores were not associated with IGF2/H19 methylation, neither in blood nor in saliva. Maternal exposure to green spaces surrounding the residence during the pregnancy was associated with IGF2/H19 ICR methylation (-0.80 % to -1.04 %, p<0.05) in saliva, but not with NR3C1 promotor methylation.

CONCLUSION

We observed significant long-term effects of maternal perceived stress during pregnancy on the methylation patterns of the NR3C1 promotor in offspring well into adulthood. This may imply that maternal psychological distress during pregnancy may influence the regulation of the HPA-axis well into adulthood. Additionally, maternal proximity to green spaces was associated with IGF2/H19 ICR methylation patterns, which is a novel finding.

Green space exposure and blood DNA methylation at birth and in childhood - A multi-cohort study

Green space exposure has been associated with improved mental, physical and general health. However, the underlying biological mechanisms remain largely unknown. The aim of this study was to investigate the association between green space exposure and cord and child blood DNA methylation. Data from eight European birth cohorts with a total of 2,988 newborns and 1,849 children were used. Two indicators of residential green space exposure were assessed: (i) surrounding greenness (satellite-based Normalized Difference Vegetation Index (NDVI) in buffers of 100 m and 300 m) and (ii) proximity to green space (having a green space ≥ 5,000 m2 within a distance of 300 m). For these indicators we assessed two exposure windows: (i) pregnancy, and (ii) the period from pregnancy to child blood DNA methylation assessment, named as cumulative exposure. DNA methylation was measured with the Illumina 450K or EPIC arrays. To identify differentially methylated positions (DMPs) we fitted robust linear regression models between pregnancy green space exposure and cord blood DNA methylation and between cumulative green space exposure and child blood DNA methylation. Two sensitivity analyses were conducted: (i) without adjusting for cellular composition, and (ii) adjusting for air pollution. Cohort results were combined through fixed-effect inverse variance weighted meta-analyses. Differentially methylated regions (DMRs) were identified from meta-analysed results using the Enmix-combp and DMRcate methods. There was no statistical evidence of pregnancy or cumulative exposures associating with any DMP (False Discovery Rate, FDR, p-value < 0.05). However, surrounding greenness exposure was inversely associated with four DMRs (three in cord blood and one in child blood) annotated to ADAMTS2, KCNQ1DN, SLC6A12 and SDK1 genes. Results did not change substantially in the sensitivity analyses. Overall, we found little evidence of the association between green space exposure and blood DNA methylation. Although we identified associations between surrounding greenness exposure with four DMRs, these findings require replication.

Critical windows of greenness exposure during preconception and gestational periods in association with birthweight outcomes

Few studies have examined the association between greenness exposure and birth outcomes. This study aims to identify critical exposure time windows during preconception and pregnancy for the association between greenness exposure and birth weight. A cohort of 13 890 pregnant women and newborns in Shanghai, China from 2016-2019 were included in the study. We assessed greenness exposure using Normalized Difference Vegetation Index (NDVI) during the preconception and gestational periods, and evaluated the association with term birthweight, birthweight z-score, small-for-gestational age, and large-for-gestational age using linear and logistic regressions adjusting for key maternal and newborn covariates. Ambient temperature, relative humidity, ambient levels of fine particles (PM2.5) and nitrogen dioxide (NO2) assessed during the same period were adjusted for as sensitivity analyses. Furthermore, we explored the potential different effects by urbanicity and park accessibility through stratified analysis. We found that higher greenness exposure at the second trimester of pregnancy and averaged exposure during the entire pregnancy were associated with higher birthweight and birthweight Z-score. Specifically, a 0.1 unit increase in second trimester averaged NDVI value was associated with an increase in birthweight of 10.2 g (95% CI: 1.8-18.5 g) and in birthweight Z-score of 0.024 (0.003-0.045). A 0.1 unit increase in an averaged NDVI during the entire pregnancy was associated with 10.1 g (95% CI: 1.0-19.2 g) increase in birthweight and 0.025 (0.001-0.048) increase in birthweight Z-score. Moreover, the associations were larger in effect size among urban residents than suburban residents and among residents without park accessibility within 500 m compared to those with park accessibility within 500 m. Our findings suggest that increased greenness exposure, particularly during the second trimester, may be beneficial to birth weight in a metropolitan area.

Methylation of serotonin regulating genes in cord blood cells: association with maternal metabolic parameters and correlation with methylation in peripheral blood cells during childhood and adolescence

BACKGROUND

Serotonin (5-hydroxytryptamine, 5-HT) signaling is involved in neurodevelopment, mood regulation, energy metabolism, and other physiological processes. DNA methylation plays a significant role in modulating the expression of genes responsible for maintaining 5-HT balance, such as 5-HT transporter (SLC6A4), monoamine oxidase A (MAOA), and 5-HT receptor type 2A (HTR2A). Maternal metabolic health can influence long-term outcomes in offspring, with DNA methylation mediating these effects. We investigated associations between maternal metabolic parameters-pre-pregnancy body mass index (pBMI), gestational weight gain (GWG), and glucose tolerance status (GTS), i.e., gestational diabetes mellitus (GDM) versus normal glucose tolerance (NGT)-and cord blood methylation of SLC6A4, MAOA, and HTR2A in participants from our PlaNS birth cohort. CpG sites (15, 9, and 2 in each gene, respectively) were selected based on literature and in silico data. Methylation levels were quantified by bisulfite pyrosequencing. We also examined the stability of methylation patterns in these genes in circulating blood cells from birth to adolescence using longitudinal DNA methylation data from the ARIES database.

RESULTS

None of the 203 PlaNS mothers included in this study had preexisting diabetes, 99 were diagnosed with GDM, and 104 had NGT; all neonates were born at full term by planned Cesarean section. Methylation at most CpG sites differed between male and female newborns. SLC6A4 methylation correlated inversely with maternal pBMI and GWG, while methylation at HTR2A site -1665 correlated positively with GWG. None of the maternal metabolic parameters statistically associated with MAOA methylation. DNA methylation data in cord blood and peripheral blood at ages 7 and 15 years were available for 808 participants from the ARIES database; 4 CpG sites (2 in SLC6A4 and 2 in HTR2A) overlapped between the PlaNS and ARIES cohorts. A positive correlation between methylation levels in cord blood and peripheral blood at 7 and 15 years of age was observed for both SLC6A4 and HTR2A CpG sites.

CONCLUSIONS

Methylation of 5-HT regulating genes in cord blood cells is influenced by neonatal sex, with maternal metabolism playing an additional role. Inter-individual variations present in circulating blood cells at birth are still pronounced in childhood and adolescence.

IL-8-mediated overexpression of ZNF274 promotes the proliferation and migration of colorectal cancer cells through the transactivation of MRPL40

Background

Colorectal cancer (CRC) is one of the most prevalent malignant tumors with high morbidity and mortality rates worldwide. ZNF274, a member of the zinc-finger-protein family of transcription factors, is critical in chromosomal remodelling and tumorigenesis. However, the role of ZNF274 in CRC and the underlying molecular mechanisms remain unclear.

Methods

Immunohistochemical analysis was performed to quantify the expression of ZNF274 in human CRC tissues. The Kaplan‒Meier method was used to analyse the relationship between ZNF274 expression and CRC prognosis. The correlation between ZNF274 expression and clinical features was analyzed using Cox regression analysis. Cell proliferation and migration were evaluated by CCK-8, colony formation, and Transwell assays. The limma R package was used to analyse IL-8-related differentially expressed genes in the GSE30364 dataset. The DAVID method was used to screen significantly enriched pathways. Chromatin immunoprecipitation (ChIP)-qPCR and luciferase reporter assays were performed to determine the transcriptional regulation of MRPL40 by ZNF274.

Results

ZNF274 was overexpressed in CRC tissues and indicated poor prognosis. High ZNF274 expression was linked to larger tumor size, invasion, lymph node metastasis, and AJCC stage. Ectopic expression promoted CRC cell proliferation and migration. Mechanistically, MRPL40 was identified as the direct target gene that transactivates the expression of ZNF274. Moreover, IL-8 upregulated ZNF274 expression in a dose-dependent manner. Downregulation of either ZNF274 or MRPL40 expression abrogated the effect of IL-8 on promoting the proliferation and migration of CRC.

Conclusion

This study revealed an oncogenic role of ZNF274 and the mechanism by which ZNF274 participated in IL-8-induced promotion of CRC progression. These findings demonstrate that ZNF274 could be used as a prognostic factor and potential therapeutic target for CRC treatment.

Ambient black carbon reaches the kidneys

BACKGROUND

Ultrafine particles, including black carbon (BC), can reach the systemic circulation and therefore may distribute to distant organs upon inhalation. The kidneys may be particularly vulnerable to the adverse effects of BC exposure due to their filtration function.

OBJECTIVES

We hypothesized that BC particles reach the kidneys via the systemic circulation, where the particles may reside in structural components of kidney tissue and impair kidney function.

METHODS

In kidney biopsies from 25 transplant patients, we visualized BC particles using white light generation under femtosecond-pulsed illumination. The presence of urinary kidney injury molecule-1 (KIM-1) and cystatin c (CysC) were evaluated with ELISA. We assessed the association between internal and external exposure matrices and urinary biomarkers using Pearson correlation and linear regression models.

RESULTS

BC particles could be identified in all biopsy samples with a geometric mean (5th, 95th percentile) of 1.80 × 103 (3.65 × 102, 7.50 × 103) particles/mm3 kidney tissue, predominantly observed in the interstitium (100 %) and tubules (80 %), followed by the blood vessels and capillaries (40 %), and the glomerulus (24 %). Independent from covariates and potential confounders, we found that each 10 % higher tissue BC load resulted in 8.24 % (p = 0.03) higher urinary KIM-1. In addition, residential proximity to a major road was inversely associated with urinary CysC (+10 % distance: -4.68 %; p = 0.01) and KIM-1 (+10 % distance: -3.99 %; p < 0.01). Other urinary biomarkers, e.g., the estimated glomerular filtration rate or creatinine clearance showed no significant associations.

DISCUSSION AND CONCLUSION

Our findings that BC particles accumulate near different structural components of the kidney represent a potential mechanism explaining the detrimental effects of particle air pollution exposure on kidney function. Furthermore, urinary KIM-1 and CysC show potential as air pollution-induced kidney injury biomarkers for taking a first step in addressing the adverse effects BC might exert on kidney function.