In utero exposure to cigarette smoke dysregulates human fetal ovarian developmental signalling

• Published in: Human reproduction (Oxford) 2014-07, Vol.29 (7), p.1471-1489
• Main Authors: Fowler, Paul A, Childs, Andrew J, Courant, Frédérique, MacKenzie, Alasdair, Rhind, Stewart M, Antignac, Jean-Philippe, Le Bizec, Bruno, Filis, Panagiotis, Evans, Fergus, Flannigan, Samantha, Maheshwari, Abha, Bhattacharya, Siladitya, Monteiro, Ana, Anderson, Richard A, O'Shaughnessy, Peter J
• Format: Article
• Language: English
• Subjects: Adult; Body Mass Index; Cell Proliferation; Cotinine - metabolism; Estrogens - metabolism; Female; Fetal Development - drug effects; Germ Cells - cytology; Human health and pathology; Humans; Immunohistochemistry; Infant, Newborn; Life Sciences; Ligands; Liver - metabolism; Maternal Exposure - adverse effects; Oocytes - cytology; Ovarian Follicle - embryology; Ovary - drug effects; Ovary - embryology; Ovary - pathology; Phenotype; Polycyclic Aromatic Hydrocarbons; Pregnancy; Pregnancy Trimester, Second; Signal Transduction; Smoking - adverse effects; Tobacco Products
• ISSN: 0268-1161; 1460-2350
• DOI: 10.1093/humrep/deu117

How does maternal cigarette smoking disturb development of the human fetal ovary? Maternal smoking increases fetal estrogen titres and dysregulates several developmental processes in the fetal ovary. Exposure to maternal cigarette smoking during gestation reduces human fetal ovarian cell numbers, germ cell proliferation and subsequent adult fecundity. The effects of maternal cigarette smoking on the second trimester human fetal ovary, fetal endocrine signalling and fetal chemical burden were studied. A total of 105 fetuses were studied, 56 from mothers who smoked during pregnancy and 49 from those who did not. Ovary, liver and plasma samples were collected from electively terminated, normally progressing, second trimester human fetuses. Circulating fetal hormones, levels of 73 fetal ovarian transcripts, protein localization, density of oocytes/primordial follicles and levels of 16 polycyclic aromatic hydrocarbons (PAHs) in the fetal liver were determined. Circulating fetal estrogen levels were very high and were increased by maternal smoking (ANOVA, P = 0.055-0.004 versus control). Smoke exposure also dysregulated (two-way ANOVA, smoking versus gestation weeks interaction, P = 0.046-0.023) four fetal ovarian genes (cytochrome P450 scc [CYP11A1], NOBOX oogenesis homeobox [NOBOX], activator of apoptosis harakiri [HRK], nuclear receptor subfamily 2, group E, member 1 [NR2E1]), shifted the ovarian Inhibin βA/inhibin α ratio (NHBA/INHA) transcript ratio in favour of activin (ANOVA, P = 0.049 versus control) and reduced the proportion of dominant-negative estrogen receptor 2 (ERβ: ESR2) isoforms in half the exposed fetuses. PAHs, ligands for the aryl hydrocarbon receptor (AHR), were increased nearly 6-fold by maternal smoking (ANOVA, P = 0.011 versus control). A fifth transcript, COUP transcription factor 1 (nuclear receptor subfamily 2, group F, member 1: NR2F1, which contains multiple AHR-binding sites), was both significantly increased (ANOVA, P = 0.026 versus control) and dysregulated by (two-way ANOVA, smoking versus gestation weeks interaction, P = 0.021) maternal smoking. NR2F1 is associated with repression of FSHR expression and smoke-exposed ovaries failed to show the normal increase in FSHR expression during the second trimester. There was a significantly higher number of DEAD (Asp-Glu-Ala-Asp) box polypeptide 4 (DDX4) VASA-positive (ANOVA, P = 0.016 versus control), but not POU domain, class 1, transcription factor 1 (POU5F1) OCT3/4-positive, oocytes