Prenatal ethanol exposure-induced a low level of foetal blood cholesterol and its mechanism of IGF1-related placental cholesterol transport dysfunction

Prenatal alcohol exposure is associated with changes in placental gene co-expression networks

Alcohol consumption during pregnancy can result in a range of adverse postnatal outcomes among exposed children. However, identifying at-risk children is challenging given the difficulty to confirm prenatal alcohol exposure and the lack of early diagnostic tools. Placental surveys present an important opportunity to uncover early biomarkers to identify those at risk. Here, we report the first transcriptome-wide evaluation to comprehensively evaluate human placental pathways altered by fetal alcohol exposure. In a prospective longitudinal birth cohort in Cape Town, South Africa, we performed bulk tissue RNAseq in placenta samples from 32 women reporting heavy drinking during pregnancy and 30 abstainers/light drinkers. Weighted gene co-expression network analysis (WGCNA) and differential gene expression analysis were performed to assess associations between fetal alcohol exposure and placental gene expression patterns at a network-wide and single gene level, respectively. The results revealed altered expression in genes related to erythropoiesis and angiogenesis, which are implicated in established postnatal phenotypes related to alcohol exposure, including disruptions in iron homeostasis, growth, and neurodevelopment. The reported findings provide insights into the molecular pathways affected by prenatal alcohol exposure and highlight the potential of placental biomarkers for detecting and understanding the effects of alcohol on fetal development.

Effects of Genetics and Sex on Acute Gene Expression Changes in the Hippocampus Following Neonatal Ethanol Exposure in BXD Recombinant Inbred Mouse Strains

Fetal alcohol spectrum disorders (FASD) are prevalent neurodevelopmental disorders. Genetics have been shown to have a role in the severity of alcohol's teratogenic effects on the developing brain. We previously identified recombinant inbred BXD mouse strains that show high (HCD) or low cell death (LCD) in the hippocampus following ethanol exposure. The present study aimed to identify gene networks that influence this susceptibility. On postnatal day 7 (3rd-trimester-equivalent), male and female neonates were treated with ethanol (5.0 g/kg) or saline, and hippocampi were collected 7hrs later. Using the Affymetrix microarray platform, ethanol-induced gene expression changes were identified in all strains with divergent expression sets found between sexes. Genes, such as Bcl2l11, Jun, and Tgfb3, showed significant strain-by-treatment interactions and were involved in many apoptosis pathways. Comparison of HCD versus LCD showed twice as many ethanol-induced genes changes in the HCD. Interestingly, these changes were regulated in the same direction suggesting (1) more perturbed effects in HCD compared to LCD and (2) limited gene expression changes that confer resistance to ethanol-induced cell death in LCD. These results demonstrate that genetic background and sex are important factors that affect differential cell death pathways after alcohol exposure during development that could have long-term consequences.

Prenatal ethanol exposure increases maternal bile acids through placental transport pathway

High maternal serum bile acid level is common and sometimes harmful to the gravida. This study aimed to confirm the bile acid phenotypic change caused by prenatal ethanol exposure (PEE) and elucidate its placental mechanism. Pregnant Wistar rats were administered intragastrically with ethanol 4 g/kg⋅d from gestational day 9-20. Total bile acids (TBA) were detected in maternal, fetal serum and placental tissues, increasing significantly in the serum but no significant change in the placental tissues. Meta-analysis was performed and verified the efficacy of the PEE-induced model based on published data from several relevant studies. Mining of microarray data from human and rat placental sources identified the involvement of bile acid metabolism and its significant genes, which were verified by RT-qPCR and western blotting on tissues and treated BeWo cells with the administration of FXR/PXR siRNAs or FXR/PXR agonists. Our examination, consistent with microarray data and wet experiments, showed that organic anion transporter polypeptide-related protein 2B1 (Oatp2b1), multidrug resistance-associated proteins 3 (Mrp3) and breast cancer resistance protein (Bcrp) expression were increased, while nuclear receptor farnesoid X receptor (Fxr) was decreased but pregnane X receptor (Pxr) was increased. Furthermore, the interventional experiments confirmed that FXR regulated Bcrp while PXR regulated Oatp2b1 and Mrp3. In summary, PEE could induce high bile acid level in maternal serum and its mechanism is associated with the high expression of BCRP/MRP3/OATP2B1 in the placenta through up-regulating PXR and down-regulating FXR, thereby leading to an excessive bile acid transport to maternal blood via the placenta. Our study provides a novel perspective in terms of placenta, explaining the increased maternal blood bile acids under the toxicity of PEE.

Bioinformatics analysis of candidate genes involved in ethanol-induced microtia pathogenesis based on a human genome database: GeneCards

OBJECTIVE

Ethanol used by women during pregnancy increases the risk for microtia in the foetus. Traditionally, laboratory experiments and Mouse Genome Informatics (MGI) have been used to explore microtia pathogenesis. The aim of this study was to screen and verify hub genes involved in ethanol-induced microtia and to explore the potential molecular mechanisms.

METHODS

Overlapping genes related to ethanol and microtia were acquired from the GeneCards database and filtered by confidence score. These genes were further analysed via bioinformatics. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis results were visualized with the clusterProfiler R package. A protein-protein interaction (PPI) network was constructed based on data from the Search Tool for the Retrieval of Interacting Genes/Proteins (STRING) database.

RESULTS

Overall, 41 genes related to both ethanol and microtia were identified. The genes most relevant to ethanol-induced microtia pathogenesis included FGFR-2, FGFR-3, FGF-8, TP53, IGF1, SHH, CTNNB1, and PAX6, among others. Most genes were strongly enriched for tissue and organ development in GO analysis. Additionally, many genes were enriched in the Ras, FoxO, MAPK, and PI3K-Akt signalling pathways in KEGG analysis.

CONCLUSIONS

Bioinformatics analysis was conducted on genes currently known to be related to ethanol-induced microtia pathogenesis. We propose that mechanisms involving FGF-family genes, TP53, IGF1 and SHH contribute significantly to ethanol-induced microtia and the accompanying malformation of other structures.

The Placenta as a Target for Alcohol During Pregnancy: The Close Relation with IGFs Signaling Pathway

Alcohol is one of the most consumed drugs in the world, even during pregnancy. Its use is a risk factor for developing adverse outcomes, e.g. fetal death, miscarriage, fetal growth restriction, and premature birth, also resulting in fetal alcohol spectrum disorders. Ethanol metabolism induces an oxidative environment that promotes the oxidation of lipids and proteins, triggers DNA damage, and advocates mitochondrial dysfunction, all of them leading to apoptosis and cellular injury. Several organs are altered due to this harmful behavior, the brain being one of the most affected. Throughout pregnancy, the human placenta is one of the most important organs for women's health and fetal development, as it secretes numerous hormones necessary for a suitable intrauterine environment. However, our understanding of the human placenta is very limited and even more restricted is the knowledge of the impact of toxic substances in its development and fetal growth. So, could ethanol consumption during this period have wounding effects in the placenta, compromising proper fetal organ development? Several studies have demonstrated that alcohol impairs various signaling cascades within G protein-coupled receptors and tyrosine kinase receptors, mainly through its action on insulin and insulin-like growth factor 1 (IGF-1) signaling pathway. This last cascade is involved in cell proliferation, migration, and differentiation and in placentation. This review tries to examine the current knowledge and gaps in our existing understanding of the ethanol effects in insulin/IGFs signaling pathway, which can explain the mechanism to elucidate the adverse actions of ethanol in the maternal-fetal interface of mammals.