No abstract

OBJECTIVE: The prevalent use of e-cigarettes and other nicotine products are increasing among women of reproductive age, making their effect on pregnancy an important public health concern. Nicotine is associated with adverse effects on the fetus including reduced placental blood perfusion and decreased fetal pulmonary function. Utilizing a rat model of in utero nicotine exposure, we have recently demonstrated epigenetic alterations in the lung and brain of offspring at postnatal day 1. Moreover, previous studies in nonhuman primates show effects of nicotine on fetal pulmonary function and oxidant radical production, and these effects are mitigated by treatment with the anti-oxidant Vitamin C (VC). Studies have also shown that nicotine is a potent histone deacetylase inhibitor. Based on these observations, we sought to determine the underlying molecular mechanisms. We hypothesized that differential histone post translational modifications (PTMs) would be detected in these tissues in response to nicotine, which may be further modulated upon Vit C treatment. STUDY DESIGN: In this preclinical study, PTMs were investigated in histones isolated from fetal lung and placenta from near term Rhesus macaques. Mothers received Vit C (VC) or placebo, and nicotine or saline to yield six different treatment groups (n¼7-9); control (placebo + saline), saline + 50mg/kg VC or 250mg/kg VC, nicotine + placebo, and nicotine + 50mg/kg or 250 mg/kg VC daily. Western blots were performed for the following histone PTMs: H3K4me3, H3K9me3, H3K27me3, H3K9ac, H3K14ac, H3PanAc and H4PanAc. Total histone H3 was used for normalization. RESULTS: As shown (Figure), analysis of specific histone PTMs demonstrate a significant difference between control and nicotine + 250mg/kg Vit C (NVC) groups in the placenta (H3K9me3, H3K9Ac, H3K27me3; p¼0.016, 0.027, 0.027 respectively) and in the lung (H3K4me3; p¼0.039). CONCLUSION: Nicotine and Vit C demonstrated a significant synergistic effect on the fetal placental and lung epigenome, with notable site-specific histone PTMs. Further study is warranted to investigate the effects of these epigenomic modifications on fetal lung and placental transcriptional networks following nicotine and Vit C exposure. These findings suggest that while Vit C may abrogate clinical impacts of nicotine exposure, the mechanisms are distinct.126 To inhale or not to inhale: a descriptive study of marijuana use and its effects in pregnancy from a contemporary large, population based cohort