Epigenetic modifications in the ferroptosis pathway in cord blood cells from newborns of smoking mothers and their influence on fetal growth.

Maternal smoking during pregnancy increases oxidative stress and decreases antioxidant capacity in newborns. Uncontrolled oxidative stress plays a role in fetal development disorders and in adverse perinatal outcomes. In order to identify molecular pathways involved in low fetal growth, epigenetic modifications in newborns of smoking and non-smoking mothers were examined. Low birth weight newborns of mothers who smoked more than 10 cigarettes per day during the first trimester of pregnancy and normal birth weight newborns of mothers who did not smoke during pregnancy were included in the study. DNA was extracted from umbilical cord blood of term newborns. 125 differentially methylated regions were identified by MeDIP-Seq. Functional analysis revealed several pathways, such as ferroptosis, that were enriched in differentially methylated genes after prenatal smoke exposure. GPX4 and PCBP1 were found to be hypermethylated and associated with low fetal growth. These epigenetic modifications in ferroptosis pathway genes in newborns of smoking mothers can potentially contribute to intrauterine growth restriction through the induction of cell death via lipid peroxidation of cell membranes. The identification of epigenetic modifications in the ferroptosis pathway sheds light on the potential mechanisms underlying the pathophysiology of low birth weight in infants born to smoking mothers.

Familial short stature and intrauterine growth retardation associated with a novel mutation in the IGF-I receptor (IGF1R) gene.

CONTEXT: IGF-I is essential for normal human growth and mediates its effects through the IGF1R. IGF1R mutations have been associated with varying degrees of intrauterine and postnatal growth retardation. OBJECTIVE: To identify IGF1R gene mutations in a short-statured family with intrauterine growth retardation and microcephaly. METHODS: Direct DNA sequencing was used to identify IGF1R mutations. Multiplex ligation-dependent probe amplification analyses were performed for deletions and duplications of all IGF1R exons. Functional studies were conducted to assess mutation pathogenicity. RESULTS: A novel heterozygous IGF1R missense mutation in exon 7 (c.A1549T, p.Y487F) was identified in a short-statured girl with severe prenatal growth retardation and microcephaly. The same mutation was also identified in her mother, who presented prenatal and postnatal growth failure, and her short-statured maternal grandmother, both of whom exhibited microcephaly. The index case showed a partial response to rhGH. Functional studies performed in dermal fibroblasts from the index case and her mother showed normal IGF-I binding; however, IGF-I activation of intracellular signalling measured as AKT and extracellular signal-regulated kinase phosphorylation was markedly reduced, with patients' values being lower than those of her mother. IGF-I stimulation of DNA synthesis was significantly reduced compared with controls. CONCLUSION: Our results show a novel missense mutation in the IGF1R gene (c.A1549T, p.Y487F) associated with prenatal and postnatal growth failure and microcephaly in the context of familial short stature. The functional studies are in line with the inactivation of one copy of the IGF1R gene with variable expression within the same family.

Identification of miRNAs Involved in Foetal Growth Restriction Due to Maternal Smoking during Pregnancy.

INTRODUCTION: Smoking during pregnancy is associated with reduced foetal growth, amongst other effects. Epigenetic modification in the foetus and placenta during embryonic development as a result of changes in the function of miRNAs is one of the pathophysiological mechanisms responsible for this. This dysregulation may be due to environmental changes or toxins such as tobacco. OBJECTIVE: To study the impact of smoking during pregnancy and its role in intrauterine growth restriction via hypermethylated miRNAs. MATERIALS AND METHODS: The differences in methylation patterns for miRNAs in umbilical cord blood from low-birth-weight newborns of smoking mothers were compared with those from normal-weight newborns using MedIP-seq (StarArray). RESULTS: Seven hypermethylated miRNAs were identified in the epigenetic study of cord blood from low-birth-weight newborns of smoking mothers in our sample. The miRNAs found to be hypermethylated were: MIR7-1, MIR3918, MIR1244-1, MIR4721, MIR25, MIR93, MIR3656. CONCLUSION: Intrauterine exposure to tobacco induces hypermethylation-mediated miRNA silencing in low-birth-weight newborns by modifying the expression of factors involved in vascular development, growth, and adaptation to hypoxia.

Study of apoptosis and related proteins, CRH and hpGH in placentas of newborns small for gestational age (SGA).

UNLABELLED: The aim of this study is to quantify the expression of apoptotic genes and genes related to the development and growth in placentas of pregnancies with IUGR (intrauterine growth restriction) and normal placentas. We studied the expression of Bcl-2, Caspase3, hpGH (human placental growth hormone) and CRH (corticotropin releasing hormone) genes in normal and IUGR placentas. In addition we have demonstrated this expression by immunohistochemical techniques. MATERIAL AND METHODS: Placentas of newborns with intrauterine infections, complicated pregnancies, congenital malformations and birth asphyxia were excluded. RNA extraction and purification. Total RNA was extracted and cleansed from the lysate using RNA wiz (Ambion) and Qiagen Rneasy Mini (Qiagen). cDNA synthesis. This assay was performed using the Retroscript Kit, Ambion. RT-PCR was performed with the LightCycler System 2.0 (Roche Diagnostics) and the LightCycler FastStart DNA Master Plus SYBR Green I. An immunochemical study was performed using the Envision Plus Dako protocol. RESULTS: Bcl-2, hpGH and CRH are down regulated in the SGA group in comparison to the control group. Caspase3 is up regulated in the SGA group in comparison to the control group. We demonstrated that in placentas from pregnancies with IUGR, expression of Bcl-2is diminished and expression of caspase 3 is augmented compared to normal placentas.