Prenatal exposure to environmental air pollution and psychosocial stress jointly contribute to the epigenetic regulation of the serotonin transporter gene in newborns

Abstract

Antenatal exposures to maternal stress and to particulate matter with an aerodynamic diameter of less than 2.5 μm (PM 2.5 ) have been independently associated with developmental outcomes in early infancy and beyond. Knowledge about their joint impact, as well as possible biological mechanisms of their effects, is still limited. Both PM 2.5 and maternal stress exposure during pregnancy might result in altered patterns of DNA methylation in speci c stress-related genes, such as the serotonin transporter gene (SLC6A4 DNAm), that might, in turn, in uence infant development. Here, we investigated the independent and interactive in uence of variations in antenatal exposures to maternal pandemic-related stress (PRS) and PM 2.5 on SLC6A4 DNAm levels in newborns. Mother-infant dyads (N=307) were enrolled at delivery during the COVID-19 pandemic. Infants' methylation status was assessed in 13 CpG sites within the SLC6A4 gene's region (chr17:28562750-28562958) in buccal cells at birth and women retrospectively report on PRS. PM 2.5 exposure over gestation and at each gestational trimester was estimated using a spatiotemporal model based on residential address. Higher levels of SLC6A4 DNAm at 6 CpG sites were found in newborns born to mothers reporting higher levels of antenatal PRS and greater PM 2.5 exposure across gestation, while adjusting for infant's sex. These effects were especially evident when exposure to elevated PM 2.5 occurred during the second trimester of pregnancy. Understanding the interplay between environmental and individual-level stressors has important implications for the improvement of mother-infant health during and after the pandemic.

Editorial: Climate change challenge in pediatric psychology

“…Studies have shown that exposure to climate-related disasters can lead to increased rates of post-traumatic stress disorder, anxiety, and depression in children (Sharpe and Davison, 2021 ; Rothschild and Haase, 2023 ). Furthermore, not only the direct exposure to polluted environments (Shezi and Wright, 2018 ; Nazzari et al, 2023 ; Pili et al, 2024 ), but also the chronic stress associated with the uncertainty and fear surrounding climate change can have long-lasting effects on children's emotional development and resilience (Léger-Goodes et al, 2022 ). While the consequences of this environmental crisis are wide-ranging, one area often overlooked is its profound impact on the mental health of our children.…”