Prenatal Ethanol Exposure Research Articles

Epigenetic Impacts of Early Life Stress in Fetal Alcohol Spectrum Disorders Shape the Neurodevelopmental Continuum.

Neurodevelopment in humans is a long, elaborate, and highly coordinated process involving three trimesters of prenatal development followed by decades of postnatal development and maturation. Throughout this period, the brain is highly sensitive and responsive to the external environment, which may provide a range of inputs leading to positive or negative outcomes. Fetal alcohol spectrum disorders (FASD) result from prenatal alcohol exposure (PAE). Although the molecular mechanisms of FASD are not fully characterized, they involve alterations to the regulation of gene expression via epigenetic marks. As in the prenatal stages, the postnatal period of neurodevelopment is also sensitive to environmental inputs. Often this sensitivity is reflected in children facing adverse conditions, such as maternal separation. This exposure to early life stress (ELS) is implicated in the manifestation of various behavioral abnormalities. Most FASD research has focused exclusively on the effect of prenatal ethanol exposure in isolation. Here, we review the research into the effect of prenatal ethanol exposure and ELS, with a focus on the continuum of epigenomic and transcriptomic alterations. Interestingly, a select few experiments have assessed the cumulative effect of prenatal alcohol and postnatal maternal separation stress. Regulatory regions of different sets of genes are affected by both treatments independently, and a unique set of genes are affected by the combination of treatments. Notably, epigenetic and gene expression changes converge at the clustered protocadherin locus and oxidative stress pathway. Functional studies using epigenetic editing may elucidate individual contributions of regulatory regions for hub genes and further profiling efforts may lead to the development of non-invasive methods to identify children at risk. Taken together, the results favor the potential to improve neurodevelopmental outcomes by epigenetic management of children born with FASD using favorable postnatal conditions with or without therapeutic interventions.

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.

Pravastatin ameliorated osteoarthritis susceptibility in male offspring rats induced by prenatal ethanol exposure.

Osteoarthritis (OA) is a disease associated with a disorder of cholesterol metabolism. Our previous studies showed that prenatal ethanol exposure (PEE) caused cholesterol accumulation in articular cartilage and increased the susceptibility to OA in offspring. However, we did not determine whether pravastatin, a cholesterol-lowering agent, could rescue PEE-induced susceptibility to OA. Here, fetal rats were divided into a PEE group and a control group during pregnancy. At postnatal week (PW) 8, sixteen male offspring rats from both groups were injected papain through the articular cavity. Eight of them from each group were treated with pravastatin (20mg/kg·d) by gavage for four weeks simultaneously. We found that pravastatin ameliorated papain-induced high expression of inflammatory factors [interleukin (IL)-1, IL-6], matrix degradation enzymes [matrix metalloproteinase (MMP)-3, MMP-13], and apoptosis factors (caspase-3 and caspase-8) in the cartilage of the PEE group. Also, pravastatin significantly reduced the content of TCH in the blood and cartilage of the PEE offspring and improved cholesterol efflux pathway. Our in vitro findings further confirmed that pravastatin partially reversed cholesterol-induced inflammation and apoptosis of chondrocytes. In conclusion, pravastatin effectively reduced inflammation and matrix degradation, and thus ameliorate OA susceptibility in articular cartilage by relieving cholesterol accumulation in chondrocyte.

Moderate prenatal ethanol exposure leads to attention deficits in both male and female rats

Attention deficits caused by prenatal ethanol (EtOH) exposure (PE) are a prevalent condition in fetal alcohol spectrum disorders (FASDs). Importantly, the deficits are observed in individuals with FASD who have normal IQs and show no dysmorphic facial features caused by heavy PE. These observations suggest that even moderate PE could lead to attention deficits. This possibility was investigated in the present study using a rat model. Pregnant Sprague Dawley rats were administered EtOH (3g/kg/day) or vehicle via intragastric gavage on gestational days 8 to 20. The blood EtOH concentration (BEC) in EtOH-treated rats was 87.7±1.2mg/dl (1h after the gavage), similar to the BECs reported in other moderate PE studies in rodents. Moderate PE did not produce teratogenic effects on birthweight or litter size. The adult offspring underwent a 2-choice reaction time task. Moderate PE led to augmented action impulsivity in both sexes, indicated by more rapid response initiation and more premature responses. Deficits were more marked in males than in females. No greater lapses of attention, assessed by incorrect or relatively slow responses, were observed in rats of either sex with moderate PE. In addition, no deficits in learning or motor function were detected after moderate PE. Interestingly, rats with moderate PE completed more trials than controls. Our results confirm that moderate PE leads to attention deficits in both sexes, which is demonstrated by greater action impulsivity, but not more lapses of attention. This effect differs from that of heavy PE, as shown in our previous study, which is manifested as impaired action impulsivity and lapses of attention in both sexes.

Alteration of CYP2E1, DBN1, DNMT1, miRNA-335, miRNA-21, c-Fos and Cox-2 gene expression in prefrontal cortex of rats’ offspring submitted to prenatal ethanol exposure during their neurodevelopment and the preventive role of nancocurcumin administration: A histological, ultrastructural and molecular study

Ethanol (EtOH) has been linked to neurotoxic effects on the fetus and prenatal alcohol exposure (PAE) has a negative impact on brain neurodevelopment. Therefore, the present study was aimed to focus on the underlying mechanisms of alcohol-induced oxidative stress and apoptotic cell death in addition to shedding the light on the modulatory effect of nanocurcumin in rats’ offspring prefrontal cortices. The current study investigated the effects of prenatal maternal exposure to EtOH intragastric (i.g.) administration of 0.015 mL/g of a 10 % v/v ethanol solution throughout gestation and the concomitant use of nanocurcumin, on 21-day-old offspring Wistar rat prefrontal cortex parameters. CYP2E1, DBN1, DNMT1, miRNA-335, miRNA-21, c-Fos and Cox-2 gene expression as well as the accompanying histological and ultrastructural alterations were assessed. The implemented experimental setting has revealed that ethanol exposure caused significant alterations in the above mentioned parameters. Changes observed in nanocurcumin-treated animals were significantly different to the ethanol-treated group when nanocurcumin was concomitantly administered.

Prenatal ethanol exposure impairs the formation of radial glial fibers and promotes the transformation of GFAPδ‑positive radial glial cells into astrocytes.

During embryonic cortical development, radial glial cells (RGCs) are the major source of neurons, and these also serve as a supportive scaffold to guide neuronal migration. Similar to Vimentin, glial fibrillary acidic protein (GFAP) is one of the major intermediate filament proteins present in glial cells. Previous studies confirmed that prenatal ethanol exposure (PEE) significantly affected the levels of GFAP and increased the disassembly of radial glial fibers. GFAPδ is a variant of GFAP that is specifically expressed in RGCs; however, to the best of our knowledge, there are no reports regarding how PEE influences its expression during cortical development. In the present study, the effects of PEE on the expression and distribution of GFAPδ during early cortical development were assessed. It was found that PEE significantly decreased the expression levels of GFAP and GFAPδ. Using double immunostaining, GFAPδ was identified to be specifically expressed in apical and basal RGCs, and was co-localized with other intermediate filament proteins, such as GFAP, Nestin and Vimentin. Additionally, PEE significantly affected the morphology of radial glial fibers and altered the behavior of RGCs. The loss of GFAPδ accelerated the transformation of RGCs into astrocytes. Using co-immunostaining with Ki67 or phospho-histone H3, GFAPδ+ cells were observed to be proliferative or mitotic cells, and ethanol treatment significantly decreased the proliferative or mitotic activities of GFAPδ+ RGCs. Taken together, the results suggested that PEE altered the expression patterns of GFAPδ and impaired the development of radial glial fibers and RGC behavior. The results of the present study provided evidence that GFAPδ may be a promising target to rescue the damage induced by PEE.

Enhancement of parvalbumin interneuron-mediated neurotransmission in the retrosplenial cortex of adolescent mice following third trimester-equivalent ethanol exposure

Prenatal ethanol exposure causes a variety of cognitive deficits that have a persistent impact on quality of life, some of which may be explained by ethanol-induced alterations in interneuron function. Studies from several laboratories, including our own, have demonstrated that a single binge-like ethanol exposure during the equivalent to the third trimester of human pregnancy leads to acute apoptosis and long-term loss of interneurons in the rodent retrosplenial cortex (RSC). The RSC is interconnected with the hippocampus, thalamus, and other neocortical regions and plays distinct roles in visuospatial processing and storage, as well as retrieval of hippocampal-dependent episodic memories. Here we used slice electrophysiology to characterize the acute effects of ethanol on GABAergic neurotransmission in the RSC of neonatal mice, as well as the long-term effects of neonatal ethanol exposure on parvalbumin-interneuron mediated neurotransmission in adolescent mice. Mice were exposed to ethanol using vapor inhalation chambers. In postnatal day (P) 7 mouse pups, ethanol unexpectedly failed to potentiate GABAA receptor-mediated synaptic transmission. Binge-like ethanol exposure of P7 mice expressing channel rhodopsin in parvalbumin-positive interneurons enhanced the peak amplitudes, asynchronous activity and total charge, while decreasing the rise-times of optically-evoked GABAA receptor-mediated inhibitory postsynaptic currents in adolescent animals. These effects could partially explain the learning and memory deficits that have been documented in adolescent and young adult mice exposed to ethanol during the third trimester-equivalent developmental period.

Folic acid prevents functional and structural heart defects induced by prenatal ethanol exposure

Increased regurgitant blood flow has been linked to endocardial cushion defects and resultant congenital heart diseases (CHDs). Prenatal alcohol exposure (PAE) has been shown to alter early blood flow resulting in abnormal endocardial cushions and CHDs. Compounds, including folic acid (FA), mitigate PAE effects and prevent CHDs, but few studies have assessed their effects on blood flow. We modeled binge drinking in quail embryos at gastrulation. Embryos were exposed to ethanol alone, FA (3.2 μg/egg) alone, and the two simultaneously. We quantified in cardiac looping stages (equivalent to 4 weeks of human gestation) regurgitant blood flow with Doppler optical coherence tomography (OCT) and endocardial cushion volumes using OCT imaging. Incidences of abnormal body curvature and heart rates were also measured. Embryos exposed to ethanol showed significantly increased regurgitant blood flow compared to controls, while embryos given FA with ethanol had significantly reduced regurgitant blood flow but did not return to control levels. Ethanol exposure led to significantly smaller, abnormal endocardial cushions and the addition of FA improved their size, but they remained smaller than controls. Abnormal body curvatures after PAE were reduced in incidence but not fully prevented by FA. FA supplementation partially alleviated PAE induced abnormal cardiovascular function and morphology. Normal blood flow and endocardial cushions are both required to produce a healthy four-chambered heart. These findings support that FA supplementation should begin early in pregnancy to prevent heart as well as neural tube defects. Investigations into the efficacy of combinations of compounds to prevent PAE-induced defects is warranted.

Resveratrol reverses the programmed high-susceptibility to non-alcoholic fatty liver disease by targeting the hepatic SIRT1-SREBP1c pathway in prenatal ethanol-exposed rat offspring.

An increased susceptibility to non-alcoholic fatty liver disease (NAFLD) in female rat offspring that experienced prenatal ethanol exposure (PEE) has been previously demonstrated. The present study further investigated the potential mechanism. Based on the results from both fetal and adult studies of offspring rats that experienced PEE (4 g/kg/day), the fetal weight, serum glucose and triglyceride levels decreased significantly and hepatocellular ultra-structure was altered. Fetal livers exhibited inhibited expression and activity of sirtuin 1 (SIRT1), enhanced expression of lipogenic genes: sterol regulatory element binding protein 1c (SREBP1c), fatty acid synthase (FASN), acetyl-coenzyme A carboxylase α (ACCα), stearyl-coenzyme A desaturase 1 (SCD1). In adult offspring fed with high-fat diet, the PEE offspring revealed obviously catch-up growth, increased food intake, elevated serum metabolic phenotypes, suppressed hepatic SIRT1-SREBP1c pathway, and formation of NAFLD. Resveratrol (the chemical activator of SIRT1) could remarkably reverse the serum metabolic phenotypes and alleviate the hepatocyte steatosis in relation to the PEE offspring through activating the hepatic SIRT1-SREBP1c pathway. Therefore, increased susceptibility to diet-induced NAFLD in PEE offspring appears to be mediated by intrauterine programming of hepatic lipogenesis via the SIRT1-SREBP1c pathway. This altered programming effect could partially be reversed by resveratrol intervention after birth in PEE offspring rats.

Mechanisms of Prenatal Ethanol Exposure on Causing Developmental Defects Associated with Fetal Alcohol Syndrome Disorders

Mechanisms of Prenatal Ethanol Exposure on Causing Developmental Defects Associated with Fetal Alcohol Syndrome Disorders

Dose-response analysis of microvasculature changes in the murine fetal brain and the maternal extremities due to prenatal ethanol exposure

.Significance: Prenatal exposure to ethanol causes several morphological and neurobehavioral deficits. While there are some studies on the effects of ethanol exposure on blood flow, research focusing on acute changes in the microvasculature is limited.Aim: The first aim of this study was to assess the dose-dependent changes in murine fetal brain microvasculature of developing fetuses in response to maternal alcohol consumption. The second aim was to quantify changes in vasculature occurring concurrently in the mother’s hindlimb and the fetus’s brain after maternal exposure to alcohol.Approach: Correlation mapping optical coherence angiography was used to evaluate the effects of prenatal exposure to different doses of ethanol (3, 1.5, and ) on murine fetal brain vasculature in utero. Additionally, simultaneous imaging of maternal peripheral vessels and the fetal brain vasculature was performed to assess changes of the vasculature occurring concurrently in response to ethanol consumption.Results: The fetal brain vessel diameters (VDs) decreased by , 30%, and 14% in response to ethanol doses of 3, 1.5, and , respectively. However, the mother’s hindlimb VD increased by 63% in response to ethanol at a dose of .Conclusions: Results showed a dose-dependent reduction in vascular blood flow in fetal brain vessels when the mother was exposed to ethanol, whereas vessels in the maternal hindlimb exhibited concurrent vasodilation.

A novel Oct4/Pou5f1-like non-coding RNA controls neural maturation and mediates developmental effects of ethanol

Prenatal ethanol exposure can result in loss of neural stem cells (NSCs) and decreased brain growth. Here, we assessed whether a noncoding RNA (ncRNA) related to the NSC self-renewal factor Oct4/Pou5f1, and transcribed from a processed pseudogene locus on mouse chromosome 9 (mOct4pg9), contributed to the loss of NSCs due to ethanol. Mouse fetal cortical-derived NSCs, cultured ex vivo to mimic the early neurogenic environment of the fetal telencephalon, expressed mOct4pg9 ncRNA at significantly higher levels than the parent Oct4/Pou5f1 mRNA. Ethanol exposure increased expression of mOct4pg9 ncRNA, but decreased expression of Oct4/Pou5f1. Gain- and loss-of-function analyses indicated that mOct4pg9 overexpression generally mimicked effects of ethanol exposure, resulting in increased proliferation and expression of transcripts associated with neural maturation. Moreover, mOct4pg9 associated with Ago2 and with miRNAs, including the anti-proliferative miR-328-3p, whose levels were reduced following mOct4pg9 overexpression. Finally, mOct4pg9 inhibited Oct4/Pou5f1–3’UTR-dependent protein translation. Consistent with these observations, data from single-cell transcriptome analysis showed that mOct4pg9-expressing progenitors lack Oct4/Pou5f1, but instead overexpress transcripts for increased mitosis, suggesting initiation of transit amplification. Collectively, these data suggest that the inhibitory effects of ethanol on brain development are explained, in part, by a novel ncRNA which promotes loss of NSC identity and maturation.

Choline Plus Working Memory Training Improves Prenatal Alcohol-Induced Deficits in Cognitive Flexibility and Functional Connectivity in Adulthood in Rats.

Fetal alcohol spectrum disorder (FASD) is the leading known cause of intellectual disability, and may manifest as deficits in cognitive function, including working memory. Working memory capacity and accuracy increases during adolescence when neurons in the prefrontal cortex undergo refinement. Rats exposed to low doses of ethanol prenatally show deficits in working memory during adolescence, and in cognitive flexibility in young adulthood. The cholinergic system plays a crucial role in learning and memory processes. Here we report that the combination of choline and training on a working memory task during adolescence significantly improved cognitive flexibility (performance on an attentional set shifting task) in young adulthood: 92% of all females and 81% of control males formed an attentional set, but only 36% of ethanol-exposed males did. Resting state functional magnetic resonance imaging showed that functional connectivity among brain regions was different between the sexes, and was altered by prenatal ethanol exposure and by choline + training. Connectivity, particularly between prefrontal cortex and striatum, was also different in males that formed a set compared with those that did not. Together, these findings indicate that prenatal exposure to low doses of ethanol has persistent effects on brain functional connectivity and behavior, that these effects are sex-dependent, and that an adolescent intervention could mitigate some of the effects of prenatal ethanol exposure.

VP27.04: Corpus callosum as an imaging biomarker of neurodevelopmental effects of prenatal ethanol exposure

VP27.04: Corpus callosum as an imaging biomarker of neurodevelopmental effects of prenatal ethanol exposure

GABAa receptor density alterations revealed in a mouse model of early moderate prenatal ethanol exposure using [18F]AH114726

IntroductionPrenatal ethanol exposure (PEE) has been shown to alter the level and function of receptors in the brain, one of which is GABAa receptors (GABAaR), the major inhibitory ligand gated ion channels that mediate neuronal inhibition. High dose PEE in animals resulted in the upregulation of GABAaR, but the effects of low and moderate dose PEE at early gestation have not been investigated. This study aimed at examining GABAaR density in the adult mouse brain following PEE during a period equivalent to the first 3 to 4 weeks in human gestation. It was hypothesized that early moderate PEE would cause alterations in brain GABAaR levels in the adult offspring. MethodsC57BL/6J mice were given 10% v/v ethanol during the first 8 gestational days. Male offspring were studied using in-vivo Positron Emission Tomography (PET)/Magnetic Resonance Imaging (MRI), biodistribution, in-vitro autoradiography using [18F]AH114726, a novel flumazenil analogue with a high affinity for the benzodiazepine-binding site, and validated using immunohistochemistry. ResultsIn vivo PET and biodistribution did not detect alteration in brain tracer uptake. In vitro radiotracer studies detected significantly reduced GABAaR in the olfactory bulbs. Immunohistochemistry detected reduced GABAaR in the cerebral cortex, cerebellum and hippocampus, while Nissl staining showed that cell density was significantly higher in the striatum following PEE. ConclusionEarly moderate PEE may induce long-term alterations in the GABAaR system that persisted into adulthood.

Glucocorticoid-insulin-like growth factor 1 (GC-IGF1) axis programming mediated hepatic lipid-metabolic in offspring caused by prenatal ethanol exposure

Prenatal ethanol exposure (PEE) could increase offspring’s susceptibility to adult liver lipid-metabolism diseases. This study aimed to confirm intrauterine programming mechanism of glucocorticoid-insulin-like growth factor 1 (GC-IGF1) axis for liver dysfunction in offspring rats induced by PEE. The results showed that levels of hepatic IGF1, lipid metabolism-related enzymes (e.g. FASN and HMGCR) and serum phenotype (TG, TCH, HDL-C, and LDL-C) were low in fetal rats of PEE but high in adult offspring except for HDL-C, meanwhile, hepatic H3K9ac and expression levels of IGF1 were low in fetal rats but high in adult offspring. Furthermore, levels of serum corticosterone and hepatic glucocorticoid-activation system (mainly including expression of 11β-HSD1, GR, and C/EBPα as well as 11β-HSD1/11β-HSD2 ratio) were high in fetal rats of PEE but low or unchanged in adult offspring. The adult F2 generation of PEE maintained the same GC-IGF1 axis programming alteration as the F1 generation despite gender differences. In vitro, cortisol was proved to activate hepatocyte glucocorticoid-activation system and decrease H3K9ac and expression levels of IGF1 by GR. Therefore, PEE has a long-term effect on the offspring’s liver functional development, which may be mainly related to the epigenetic programming alteration of the GC-IGF1 axis mediated by the glucocorticoid-activation system.

Gene expression profiling reveals a lingering effect of prenatal alcohol exposure on inflammatory-related genes during adolescence and adulthood

Prenatal Alcohol Exposure (PAE) exerts devastating effects on the Central Nervous System (CNS), which vary as a function of both ethanol load and gestational age of exposure. A growing body of evidence suggests that alcohol exposure profoundly impacts a wide range of cytokines and other inflammation-related genes in the CNS. The olfactory system serves as a critical interface between infectious/inflammatory signals and other aspects of CNS function, and demonstrates long-lasting plasticity in response to alcohol exposure. We therefore utilized transcriptome profiling to identify gene expression patterns for immune-related gene families in the olfactory bulb of Long Evans rats. Pregnant dams received either an ad libitum liquid diet containing 35% daily calories from ethanol (ET), a pair-fed diet (PF) matched for caloric content, or free choice (FCL) access to the liquid diet and water from Gestational Day (GD) 11–20. Offspring were fostered to dams fed the FCL diet, weaned on P21, and then housed with same-sex littermates until mid-adolescence (P40) or young adulthood (P90). At the target ages of P40 or P90, offspring were euthanized via brief CO2 exposure and brains/blood were collected. Gene expression analysis was performed using a Rat Gene 1.0 ST Array (Affymetrix), and preliminary analyses focused on two moderately overlapping gene clusters, including all immune-related genes and those related to neuroinflammation. A total of 146 genes were significantly affected by prenatal Diet condition, whereas the factor of Age (P40 vs P90) revealed 998 genes significantly changed, and the interaction between Diet and Age yielded 162 significant genes. From this dataset, we applied a threshold of 1.3-fold change (30% increase or decrease in expression) for inclusion in later analyses. Findings indicated that in adolescents, few genes were altered by PAE, whereas adults displayed an increase of a wide range of gene upregulation as a result of PAE. Pathway analysis predicted an increase in Nf-κB activation in adolescence and a decrease in adulthood due to prenatal ethanol exposure, indicating age-specific and long-lasting alterations to immune signaling. These data may provide important insight into the relationship between immune-related signaling cascades and long-term changes in olfactory bulb function after PAE.

Prenatal ethanol exposure increases susceptibility to depression- and anxiety-like behavior in adult female offspring and its underlying mechanism

Epidemiological investigations have found that maternal alcohol intake increases the risk of mental illness in offspring. Our study investigated changes of depression- and anxiety-like behaviors in adult offspring caused by prenatal ethanol exposure (PEE) and explored the potential mechanism. After Wistar rats were intragastrically administered ethanol at a dose of 4 g/kg·d on the 9–20 t h days of pregnancy, the offspring were given 21 days of chronic unpredictable mild stress (CUMS) starting from the 9th week after birth. Before CUMS, the behavioral results showed that the PEE offspring appeared excited and anxious. After CUMS, the PEE offspring rats were more sensitive to the same intensity of stimulation, and then the behavioral disorders aggravated. In adult offspring from the PEE group, the intercellular space was enlarged in the hippocampus, and there was a loss of pyramidal cells. The expression of brain-derived neurotrophic factor (BDNF) decreased; the mRNA expression of the glucocorticoid receptor and synaptic plasticity-related genes decreased; the apoptosis-related genes expressed disrupted. In order to determine whether hippocampal injury and dysfunction resulted from ethanol directly or indirectly, we performed in vitro study. The outcome was accompanied by disrupted gene expression related to neurogenesis and synaptic plasticity. PEE increases the susceptibility of adult female offspring to depression- and anxiety-like behaviors, and its mechanism may be related to the toxic effects of ethanol, both directly and indirectly. The latter inhibits the hippocampal BDNF pathway, leading to the disruption of hippocampal neurogenesis, apoptosis and decreased synaptic plasticity.

Prenatal exposure to alcohol impairs social play behavior in adolescent male mice

Prenatal ethanol exposure affects brain development and causes neural impairment, leading to both cognitive and behavioral consequences in the offspring. Therefore, the aim of this study was to investigate the impact of prenatal exposure to small amounts of alcohol on social play behavior in adolescent male offspring. Swiss mice were prenatally exposed to ethanol by feeding pregnant dams with a liquid diet containing 25% alcohol-derived calories during gestation (alcohol group). They were then compared to both pair-fed dams that received an isocaloric liquid diet containing 0% alcohol-derived calories (pair-fed group) and dams with ad libitum access to a liquid control diet (control group). Additionally, maternal behavior was evaluated in terms of neural activation indexed via c-fos expression in the prefrontal cortex. Although dams exposed to alcohol during pregnancy did not alter their maternal behavior, the offspring presented a decrease in their social play behavior compared with both control and pair-fed offspring. The decrease in social play behavior may be associated with a decrease in number of c-fos-positive cells in the prefrontal cortex. The exposure to small amounts of alcohol during intrauterine development causes both a deficit in social play behavior and a reduction in the neuronal activity seen in the prefrontal cortex.

Hippocampal transcriptome analysis following maternal separation implicates altered RNA processing in a mouse model of fetal alcohol spectrum disorder

BackgroundFetal alcohol spectrum disorders (FASD) are common, seen in 1–5% of the population in the USA and Canada. Children diagnosed with FASD are not likely to remain with their biological parents, facing early maternal separation and foster placements throughout childhood.MethodsWe model FASD in mice via prenatal alcohol exposure and further induce early life stress through maternal separation. We use RNA-seq followed by clustering of expression profiles through weighted gene co-expression network analysis (WGCNA) to analyze transcriptomic changes that result from the treatments. We use reverse transcription qPCR to validate these changes in the mouse hippocampus.ResultsWe report an association between adult hippocampal gene expression and prenatal ethanol exposure followed by postnatal separation stress that is related to behavioral changes. Expression profile clustering using WGCNA identifies a set of transcripts, module 19, associated with anxiety-like behavior (r = 0.79, p = 0.002) as well as treatment group (r = 0.68, p = 0.015). Genes in this module are overrepresented by genes involved in transcriptional regulation and other pathways related to neurodevelopment. Interestingly, one member of this module, Polr2a, polymerase (RNA) II (DNA directed) polypeptide A, is downregulated by the combination of prenatal ethanol and postnatal stress in an RNA-Seq experiment and qPCR validation (q = 2e−12, p = 0.004, respectively).ConclusionsTogether, transcriptional control in the hippocampus is implicated as a potential underlying mechanism leading to anxiety-like behavior via environmental insults. Further research is required to elucidate the mechanism involved and use this insight towards early diagnosis and amelioration strategies involving children born with FASD.