RNA-seq analysis reveals prenatal alcohol exposure is associated with placental inflammatory cells and gene expression

BACKGROUND

Fetal alcohol spectrum disorders (FASD) are the most common preventable cause of birth defects and neurodevelopmental disorders worldwide. The placenta is the crucial interface between mother and fetus. Prenatal alcohol exposure (PAE) has been shown to alter placental structure and expression of genes in bulk placental tissue samples, but prior studies have not examined effects on placental cell-type composition or taken cell-type into consideration in transcriptome analyses.

METHODS

We leveraged an existent placenta single-cell RNA-seq dataset to perform cell-type deconvolution of bulk placental RNA-seq data from 35 heavy drinking pregnant women and 33 controls in a prospective birth cohort in Cape Town, South Africa. We used bivariate analyses and multivariable adjusted linear regression models to assess the relation of PAE on inferred placental cell-type proportions. We also examined differential expression of inflammatory response genes and PAE, using multivariable adjusted linear models.

RESULTS

Deconvolution analyses showed heterogeneous placenta cell-type composition in which stromal (27 %), endothelial (26 %) and cytotrophoblasts (18 %) were the predominant cell-types. PAE around conception was associated with a higher proportion of Hofbauer cells (B = 0.51, p = 0.035) in linear models adjusted for maternal age, infant sex, and gestational age. Among the 652 inflammatory genes examined, 35 were differential expressed in alcohol exposed placentas (FDR p < 0.05).

CONCLUSIONS

Our findings suggest that heavy alcohol exposure during pregnancy can influence the proportion of fetal placental villi macrophages (Hofbauer cells) and increased expression of inflammatory genes. Future studies are needed to further characterize these effects and to assess the potential functional roles of placental inflammation in FASD.

Constitutional chromosomal anomalies in children, fetal alcohol syndrome, and maternal toxicant exposures: A longitudinal cohort study

DNA alterations in gametes, which may occur either spontaneously or as a result of exposure to genotoxicants, can lead to constitutional chromosomal anomalies in the offspring. Alcohol is an established genotoxicant. The goal of this hypothesis-testing longitudinal cohort study was to evaluate the effect of significant/sustained maternal alcohol exposure on clinically diagnosed constitutional chromosomal anomalies among children diagnosed with fetal alcohol syndrome (FAS). De-identified eligibility and claim healthcare records, prospectively generated from the 1990-2012 Florida Medicaid system within the Independent Healthcare Research Database (IHRD), were analyzed. Children examined were continuously eligible with ≥ 8 outpatient office visits during the 96-month period following birth. Among these children, 377 were diagnosed with FAS and 137,135 were not. The incidence rate of chromosomal anomalies involving segregation (trisomy 13, 18, or 21, n = 625), microdeletions (microdeletion syndromes, n = 39), and point mutations (sickle-cell anemia/cystic fibrosis, n = 2570) were examined using frequency risk ratio (RR) and logistic regression (adjusted odds ratio (aOR) for sex, race, residence, socioeconomic/environmental exposure status, and birth date) models. The incidence rates of chromosomal anomalies involving segregation (RR=5.92, aOR=5.85) and microdeletions (RR=41.6, aOR=34.1) were significantly increased in the FAS cohort as compared to the non-diagnosed cohort, but there was no difference in the incidence rate of point mutations (RR=1.14, aOR=1.29). Maternal toxicant exposure should be considered in the etiology of constitutional chromosomal anomaly in offspring.

Prenatal alcohol exposure alters expression of genes involved in cell adhesion, immune response, and toxin metabolism in adolescent rat hippocampus

Prenatal alcohol exposure (PAE) can result in mild to severe consequences for children throughout their lives, with this range of symptoms referred to as Fetal Alcohol Spectrum Disorders (FASD). These consequences are thought to be linked to changes in gene expression and transcriptional programming in the brain, but the identity of those changes, and how they persist into adolescence are unclear. In this study, we isolated RNA from the hippocampus of adolescent rats exposed to ethanol during prenatal development and compared gene expression to controls. Briefly, dams were either given free access to standard chow ad libitum (AD), pair-fed a liquid diet (PF) or were given a liquid diet with ethanol (6.7% ethanol, ET) throughout gestation (gestational day (GD) 0-20). All dams were given control diet ad libitum beginning on GD 20 and throughout parturition and lactation. Hippocampal tissue was collected from adolescent male and female offspring (postnatal day (PD) 35-36). Exposure to ethanol caused widespread downregulation of many genes as compared to control rats. Gene ontology analysis demonstrated that affected pathways included cell adhesion, toxin metabolism, and immune responses. Interestingly, these differences were not strongly affected by sex. Furthermore, these changes were consistent when comparing ethanol-exposed rats to pair-fed controls provided with a liquid diet and those fed ad libitum on a standard chow diet. We conclude from this study that changes in genetic architecture and the resulting neuronal connectivity after prenatal exposure to alcohol continue through adolescent development. Further research into the consequences of specific gene expression changes on neural and behavioral changes will be vital to our understanding of the FASD spectrum of diseases.

Gastrulation-stage alcohol exposure induces similar rates of craniofacial malformations in male and female C57BL/6J mice

BACKGROUND

Prenatal alcohol exposure during gastrulation (embryonic day [E] 7 in mice, ~3rd week of human pregnancy) impairs eye, facial, and cortical development, recapitulating birth defects characteristic of Fetal Alcohol Syndrome (FAS). However, it is not known whether the prevalence or severity of craniofacial features associated with FAS is affected by biological sex.

METHODS

The current study administered either alcohol (2.9 g/kg, two i.p. doses, 4 hr apart) or vehicle to pregnant C57BL/6J females on E7, prior to gonadal sex differentiation, and assessed fetal morphology at E17.

RESULTS

Whereas sex did not affect fetal size in controls, alcohol-exposed females were smaller than both control females and alcohol-treated males. Alcohol exposure increased the incidence of eye defects to a similar degree in males and females. Together, these data suggest that females might be more sensitive to the general developmental effects of alcohol, but not effects specific to the craniofacies. Whole transcriptomic analysis of untreated E7 embryos found 214 differentially expressed genes in females vs. males, including those in pathways related to cilia and mitochondria, histone demethylase activity, and pluripotency.

CONCLUSION

Gastrulation-stage alcohol induces craniofacial malformations in male and female mouse fetuses at similar rates and severity, though growth deficits are more prevalent females. These findings support the investigation of biological sex as a contributing factor in prenatal alcohol studies.

Alternative splicing events as peripheral biomarkers for motor learning deficit caused by adverse prenatal environments

Severity of neurobehavioral deficits in children born from adverse pregnancies, such as maternal alcohol consumption and diabetes, does not always correlate with the adversity's duration and intensity. Therefore, biological signatures for accurate prediction of the severity of neurobehavioral deficits, and robust tools for reliable identification of such biomarkers, have an urgent clinical need. Here, we demonstrate that significant changes in the alternative splicing (AS) pattern of offspring lymphocyte RNA can function as accurate peripheral biomarkers for motor learning deficits in mouse models of prenatal alcohol exposure (PAE) and offspring of mother with diabetes (OMD). An aptly trained deep-learning model identified 29 AS events common to PAE and OMD as superior predictors of motor learning deficits than AS events specific to PAE or OMD. Shapley-value analysis, a game-theory algorithm, deciphered the trained deep-learning model's learnt associations between its input, AS events, and output, motor learning performance. Shapley values of the deep-learning model's input identified the relative contribution of the 29 common AS events to the motor learning deficit. Gene ontology and predictive structure-function analyses, using Alphafold2 algorithm, supported existing evidence on the critical roles of these molecules in early brain development and function. The direction of most AS events was opposite in PAE and OMD, potentially from differential expression of RNA binding proteins in PAE and OMD. Altogether, this study posits that AS of lymphocyte RNA is a rich resource, and deep-learning is an effective tool, for discovery of peripheral biomarkers of neurobehavioral deficits in children of diverse adverse pregnancies.

Breast cancer 1 (BRCA1) protection in altered gene expression and neurodevelopmental disorders due to physiological and ethanol-enhanced reactive oxygen species formation

The breast cancer 1 (Brca1) susceptibility gene regulates the repair of reactive oxygen species (ROS)-mediated DNA damage, which is implicated in neurodevelopmental disorders. Alcohol (ethanol, EtOH) exposure during pregnancy causes fetal alcohol spectrum disorders (FASD), including abnormal brain function, associated with enhanced ROS-initiated DNA damage. Herein, oxidative DNA damage in fetal brains and neurodevelopmental disorders were enhanced in saline-exposed +/- vs. +/+ Brca1 littermates. A single EtOH exposure during gestation further enhanced oxidative DNA damage, altered the expression of developmental/DNA damage response genes in fetal brains, and resulted in neurodevelopmental disorders, all of which were BRCA1-dependent. Pretreatment with the ROS inhibitor phenylbutylnitrone (PBN) blocked DNA damage and some neurodevelopmental disorders in both saline- and EtOH-exposed progeny, corroborating a ROS-dependent mechanism. Fetal BRCA1 protects against altered gene expression and neurodevelopmental disorders caused by both physiological and EtOH-enhanced levels of ROS formation. BRCA1 deficiencies may enhance the risk for FASD.

Epigenetics of Trauma Transmission and Fetal Alcohol Spectrum Disorder: What Does the Evidence Support?

Fetal alcohol spectrum disorder (FASD) results from teratogenic impacts of alcohol consumption during pregnancy. Trauma and prenatal alcohol exposure (PAE) can both cause neurodevelopmental impairment, and it has been proposed that FASD can amplify effects of trauma. Certain PAE and trauma effects are mediated via epigenetic mechanisms. The objective of this review is to present the current evidence for epigenetics in trauma transmission as it relates to FASD, to help bridge a potential knowledge gap for social workers and related health professionals. We include a primer on epigenetic mechanisms and inheritance, followed by a summary of the current biomedical evidence supporting intergenerational and transgenerational epigenetic transmission of trauma, its relevance to FASD, the intersection with social transmission, and finally the application to social work. We propose potential models of transmission, considering where social and epigenetic pathways may intersect and/or compound across generations. Overall, we aim to provide a better understanding of epigenetic-trauma transmission for its application to health professions, in particular which beliefs are (and are not) evidence-based. We discuss the lack of research and challenges of studying epigenetic transmission in humans and identify the need for public health interventions and best practices that are based on the current evidence.

Prenatal Alcohol Exposure Impairs the Placenta-Cortex Transcriptomic Signature, Leading to Dysregulation of Angiogenic Pathways

Although alcohol consumption during pregnancy is a major cause of behavioral and learning disabilities, most FASD infants are late- or even misdiagnosed due to clinician's difficulties achieving early detection of alcohol-induced neurodevelopmental impairments. Neuroplacentology has emerged as a new field of research focusing on the role of the placenta in fetal brain development. Several studies have reported that prenatal alcohol exposure (PAE) dysregulates a functional placenta-cortex axis, which is involved in the control of angiogenesis and leads to neurovascular-related defects. However, these studies were focused on PlGF, a pro-angiogenic factor. The aim of the present study is to provide the first transcriptomic "placenta-cortex" signature of the effects of PAE on fetal angiogenesis. Whole mouse genome microarrays of paired placentas and cortices were performed to establish the transcriptomic inter-organ "placenta-cortex" signature in control and PAE groups at gestational day 20. Genespring comparison of the control and PAE signatures revealed that 895 and 1501 genes were only detected in one of two placenta-cortex expression profiles, respectively. Gene ontology analysis indicated that 107 of these genes were associated with vascular development, and String protein-protein interaction analysis showed that they were associated with three functional clusters. PANTHER functional classification analysis indicated that "intercellular communication" was a significantly enriched biological process, and 27 genes were encoded for neuroactive ligand/receptors interactors. Protein validation experiments involving Western blot for one ligand-receptor couple (Agt/AGTR1/2) confirmed the transcriptomic data, and Pearson statistical analysis of paired placentas and fetal cortices revealed a negative correlation between placental Atg and cortical AGTR1, which was significantly impacted by PAE. In humans, a comparison of a 38WG control placenta with a 36WG alcohol-exposed placenta revealed low Agt immunolabeling in the syncytiotrophoblast layer of the alcohol case. In conclusion, this study establishes the first transcriptomic placenta-cortex signature of a developing mouse. The data show that PAE markedly unbalances this inter-organ signature; in particular, several ligands and/or receptors involved in the control of angiogenesis. These data support that PAE modifies the existing communication between the two organs and opens new research avenues regarding the impact of placental dysfunction on the neurovascular development of fetuses. Such a signature would present a clinical value for early diagnosis of brain defects in FASD.

ADH1B, ADH1B/C and CYP2E1 Gene Polymorphism and the Risk of Fetal Alcohol Spectrum Disorder

Increasing alcohol consumption by women of childbearing age contributes to more frequent cases of fetal alcohol spectrum disorder. The cause of the syndrome is fetal alcohol exposure, particularly what is referred to as high prenatal alcohol exposure. Low metabolic activity of fetal enzymes shifts the burden of ethanol removal to maternal metabolism. One of the factors influencing the pathogenesis of FASD is the genetic background. It can determine the rate of elimination of ethanol, thus increasing or decreasing the time of fetal exposure to ethanol and also decreasing its concentration. Genetic polymorphisms could potentially play a significant role in these processes. In the present study, we considered three polymorphisms of genes implicated in the synthesis of enzymes involved in ethanol metabolism, i.e., ADH1b (rs1229984), ADH1b/c (rs1789891), and CYP2E1 (rs3813867). The studied group consisted of 303 children and 251 mothers. Both mothers' and children's genotypes were considered in our analysis. There were no statistically significant differences between the respective groups of genotypes of the studied polymorphisms. However, the genetic background of FASD is still elusive.

Impact of alcohol exposure on neural development and network formation in human cortical organoids

Prenatal alcohol exposure is the foremost preventable etiology of intellectual disability and leads to a collection of diagnoses known as Fetal Alcohol Spectrum Disorders (FASD). Alcohol (EtOH) impacts diverse neural cell types and activity, but the precise functional pathophysiological effects on the human fetal cerebral cortex are unclear. Here, we used human cortical organoids to study the effects of EtOH on neurogenesis and validated our findings in primary human fetal neurons. EtOH exposure produced temporally dependent cellular effects on proliferation, cell cycle, and apoptosis. In addition, we identified EtOH-induced alterations in post-translational histone modifications and chromatin accessibility, leading to impairment of cAMP and calcium signaling, glutamatergic synaptic development, and astrocytic function. Proteomic spatial profiling of cortical organoids showed region-specific, EtOH-induced alterations linked to changes in cytoskeleton, gliogenesis, and impaired synaptogenesis. Finally, multi-electrode array electrophysiology recordings confirmed the deleterious impact of EtOH on neural network formation and activity in cortical organoids, which was validated in primary human fetal tissues. Our findings demonstrate progress in defining the human molecular and cellular phenotypic signatures of prenatal alcohol exposure on functional neurodevelopment, increasing our knowledge for potential therapeutic interventions targeting FASD symptoms.

Sex-Specific Whole-Transcriptome Analysis in the Cerebral Cortex of FAE Offspring

Fetal alcohol spectrum disorders (FASDs) are associated with systemic inflammation and neurodevelopmental abnormalities. Several candidate genes were found to be associated with fetal alcohol exposure (FAE)-associated behaviors, but a sex-specific complete transcriptomic analysis was not performed at the adult stage. Recent studies have shown that they are regulated at the developmental stage. However, the sex-specific role of RNA in FAE offspring brain development and function has not been studied yet. Here, we carried out the first systematic RNA profiling by utilizing a high-throughput transcriptomic (RNA-seq) approach in response to FAE in the brain cortex of male and female offspring at adulthood (P60). Our RNA-seq data analysis suggests that the changes in RNA expression in response to FAE are marked sex-specific. We show that the genes Muc3a, Pttg1, Rec8, Clcnka, Capn11, and pnp2 exhibit significantly higher expression in the male offspring than in the female offspring at P60. FAE female mouse brain sequencing data also show an increased expression of Eno1, Tpm3, and Pcdhb2 compared to male offspring. We performed a pathway analysis using a commercial software package (Ingenuity Pathway Analysis). We found that the sex-specific top regulator genes (Rictor, Gaba, Fmri, Mlxipl) are highly associated with eIF2 (translation initiation), synaptogenesis (the formation of synapses between neurons in the nervous system), sirtuin (metabolic regulation), and estrogen receptor (involved in obesity, aging, and cancer) signaling. Taken together, our transcriptomic results demonstrate that FAE differentially alters RNA expression in the adult brain in a sex-specific manner.

Gene-alcohol interactions in birth defects

Most human birth defects are thought to result from complex interactions between combinations of genetic and environmental factors. This is true even for conditions that, at face value, may appear simple and straightforward, like fetal alcohol spectrum disorders (FASD). FASD describe the full range of structural and neurological disruptions that result from prenatal alcohol exposure. While FASD require alcohol exposure, evidence from human and animal model studies demonstrate that additional genetic and/or environmental factors can influence the embryo's susceptibility to alcohol. Only a limited number of alcohol interactions in birth defects have been identified, with many sensitizing genetic and environmental factors likely yet to be identified. Because of this, while unsatisfying, there is no definitively "safe" dose of alcohol for all pregnancies. Determining these other factors, as well as mechanistically characterizing known interactions, is critical for better understanding and preventing FASD and requires combined scrutiny of human and model organism studies.

Modulation of the Drosophila transcriptome by developmental exposure to alcohol

BACKGROUND

Prenatal exposure to ethanol can cause fetal alcohol spectrum disorder (FASD), a prevalent, preventable pediatric disorder. Identifying genetic risk alleles for FASD is challenging since time, dose, and frequency of exposure are often unknown, and manifestations of FASD are diverse and evident long after exposure. Drosophila melanogaster is an excellent model to study the genetic basis of the effects of developmental alcohol exposure since many individuals of the same genotype can be reared under controlled environmental conditions.

RESULTS

We used 96 sequenced, wild-derived inbred lines from the Drosophila melanogaster Genetic Reference Panel (DGRP) to profile genome-wide transcript abundances in young adult flies that developed on ethanol-supplemented medium or standard culture medium. We found substantial genetic variation in gene expression in response to ethanol with extensive sexual dimorphism. We constructed sex-specific genetic networks associated with alcohol-dependent modulation of gene expression that include protein-coding genes, Novel Transcribed Regions (NTRs, postulated to encode long non-coding RNAs) and female-specific coordinated regulation of snoRNAs that regulate pseudouridylation of ribosomal RNA. We reared DGRP lines which showed extreme upregulation or downregulation of snoRNA expression during developmental alcohol exposure on standard or ethanol supplemented medium and demonstrated that developmental exposure to ethanol has genotype-specific effects on adult locomotor activity and sleep.

CONCLUSIONS

There is significant and sex-specific natural genetic variation in the transcriptional response to developmental exposure to ethanol in Drosophila that comprises networks of genes affecting nervous system development and ethanol metabolism as well as networks of regulatory non-coding RNAs.

Influence of COMT (rs4680) and DRD2 (rs1076560, rs1800497) Gene Polymorphisms on Safety and Efficacy of Methylphenidate Treatment in Children with Fetal Alcohol Spectrum Disorders

Fetal alcohol spectrum disorders (FASD) in a course of high prenatal alcohol exposure (hPAE) are among the most common causes of developmental disorders. The main reason for pharmacological treatment of FASD children is attention deficit hyperactivity disorder (ADHD), and methylphenidate (MPH) is the drug of choice. The aim of the study was to assess whether children born of hPAE with ADHD, with or without morphological FASD, differ in terms of catechol-O-methyltransferase (COMT) and dopamine receptor D2 (DRD2) gene polymorphisms, and if genetic predisposition affects response and safety of MPH treatment. The polymorphisms of COMT (rs4680) and DRD2 (rs1076560, rs1800497) were analyzed in DNA samples. A borderline significance was found for the correlation between MPH side effects and the G allele of COMT (rs4680) (p = 0.04994) in all ADHD children. No effect of COMT (rs4680) and DRD2 (rs1076560, rs1800497) polymorphisms and the treatment efficacy was observed. The analyzed DRD2 and COMT gene polymorphisms seem to play no role in MPH efficacy in ADHD children with hPAE, while low-activity COMT (Met158) variant carriers may be more intolerant to MPH. The MPH treatment is effective in ADHD independent of FASD, although the ADHD-FASD variant requires higher doses to be successful. These results may help in optimization and individualization in child psychiatry.

MANF is neuroprotective against ethanol-induced neurodegeneration through ameliorating ER stress

Fetal alcohol spectrum disorders (FASD) are a spectrum of developmental disorders caused by prenatal alcohol exposure. Neuronal loss or neurodegeneration in the central nervous system (CNS) is one of the most devastating features in FASD. It is imperative to delineate the underlying mechanisms to facilitate the treatment of FASD. Endoplasmic reticulum (ER) stress is a hallmark and an underlying mechanism of many neurodegenerative diseases, including ethanol-induced neurodegeneration. Mesencephalic astrocyte-derived neurotrophic factor (MANF) responds to ER stress and has been identified as a protein upregulated in response to ethanol exposure during the brain development. To investigate the role of MANF in ethanol-induced neurodegeneration and its association with ER stress regulation, we established a CNS-specific Manf knockout mouse model and examined the effects of MANF deficiency on ethanol-induced neuronal apoptosis and ER stress using a third-trimester equivalent mouse model. We found MANF deficiency exacerbated ethanol-induced neuronal apoptosis and ER stress and that blocking ER stress abrogated the harmful effects of MANF deficiency on ethanol-induced neuronal apoptosis. Moreover, using an animal model of ER-stress-induced neurodegeneration, we demonstrated that MANF deficiency potentiated tunicamycin (TM)-induced ER stress and neurodegeneration. A whole transcriptome RNA sequencing also supported the functionality of MANF in ER stress modulation and revealed targets that may mediate the ER stress-buffering capacity of MANF. Collectively, these results suggest that MANF is a neurotrophic factor that can protect neurons against ethanol-induced neurodegeneration by ameliorating ER stress.

Molecules, Mechanisms, and Disorders of Self-Domestication: Keys for Understanding Emotional and Social Communication from an Evolutionary Perspective

The neural crest hypothesis states that the phenotypic features of the domestication syndrome are due to a reduced number or disruption of neural crest cells (NCCs) migration, as these cells differentiate at their final destinations and proliferate into different tissues whose activity is reduced by domestication. Comparing the phenotypic characteristics of modern and prehistoric man, it is clear that during their recent evolutionary past, humans also went through a process of self-domestication with a simultaneous prolongation of the period of socialization. This has led to the development of social abilities and skills, especially language, as well as neoteny. Disorders of neural crest cell development and migration lead to many different conditions such as Waardenburg syndrome, Hirschsprung disease, fetal alcohol syndrome, DiGeorge and Treacher-Collins syndrome, for which the mechanisms are already relatively well-known. However, for others, such as Williams-Beuren syndrome and schizophrenia that have the characteristics of hyperdomestication, and autism spectrum disorders, and 7dupASD syndrome that have the characteristics of hypodomestication, much less is known. Thus, deciphering the biological determinants of disordered self-domestication has great potential for elucidating the normal and disturbed ontogenesis of humans, as well as for the understanding of evolution of mammals in general.

Ocular measurements in fetal alcohol spectrum disorders

Fetal alcohol spectrum disorders (FASD) describe a range of physical, behavioral, and neurologic deficits in individuals exposed to alcohol prenatally. Reduced palpebral fissure length is one of the cardinal facial features of FASD. However, other ocular measurements have not been studied extensively in FASD. Using the Fetal Alcohol Syndrome Epidemiologic Research (FASER) database, we investigated how inner canthal distance (ICD), interpupillary distance (IPD), and outer canthal distance (OCD) centiles differed between FASD and non-FASD individuals. We compared ocular measurement centiles in children with FASD to non-FASD individuals and observed reductions in all three centiles for ICD, IPD, and OCD. However, when our non-FASD children who had various forms of growth deficiency (microcephaly, short-stature, or underweight) were compared to controls, we did not observe a similar reduction in ocular measurements. This suggests that reductions in ocular measurements are a direct effect of alcohol on ocular development independent of its effect on growth parameters, which is consistent with animal models showing a negative effect of alcohol on developing neural crest cells. Interpupillary distance centile appeared to be the most significantly reduced ocular measure we evaluated, suggesting it may be a useful measure to be considered in the diagnosis of FASD.

18q12.3-q21.1 microdeletion detected in the prenatally alcohol-exposed dizygotic twin with discordant fetal alcohol syndrome phenotype

BACKGROUND

A pair of dizygotic twins discordantly affected by heavy prenatal alcohol exposure (PAE) was reported previously by Riikonen, suggesting the role of genetic risk or protective factors in the etiology of alcohol-induced developmental disorders. Now, we have re-examined these 25-year-old twins and explored genetic origin of the phenotypic discordancy reminiscent with fetal alcohol syndrome (FAS). Furthermore, we explored alterations in DNA methylation profile of imprinting control region at growth-related insulin-like growth factor 2 (IGF2)/H19 locus in twins' white blood cells (WBC), which have been associated earlier with alcohol-induced genotype-specific changes in placental tissue.

METHODS

Microarray-based comparative genomic hybridization (aCGH) was used to detect potential submicroscopic chromosomal abnormalities, and developmental as well as phenotypic information about twins were collected. Traditional bisulfite sequencing was used for DNA methylation analysis.

RESULTS

Microarray-based comparative genomic hybridization revealed a microdeletion 18q12.3-q21.1. in affected twin, residing in a known 18q deletion syndrome region. This syndrome has been associated with growth restriction, developmental delay or intellectual deficiency, and abnormal facial features in previous studies, and thus likely explains the phenotypic discordancy between the twins. We did not observe association between WBCs' DNA methylation profile and PAE, but interestingly, a trend of decreased DNA methylation at the imprinting control region was seen in the twin with prenatal growth retardation at birth.

CONCLUSIONS

The microdeletion emphasizes the importance of adequate chromosomal testing in examining the etiology of complex alcohol-induced developmental disorders. Furthermore, the genotype-specific decreased DNA methylation at the IGF2/H19 locus cannot be considered as a biological mark for PAE in adult WBCs.

Fetal Alcohol Spectrum Disorder: Embryogenesis Under Reduced Retinoic Acid Signaling Conditions

Fetal Alcohol Spectrum Disorder (FASD) is a complex set of developmental malformations, neurobehavioral anomalies and mental disabilities induced by exposing human embryos to alcohol during fetal development. Several experimental models and a series of developmental and biochemical approaches have established a strong link between FASD and reduced retinoic acid (RA) signaling. RA signaling is involved in the regulation of numerous developmental decisions from patterning of the anterior-posterior axis, starting at gastrulation, to the differentiation of specific cell types within developing organs, to adult tissue homeostasis. Being such an important regulatory signal during embryonic development, mutations or environmental perturbations that affect the level, timing or location of the RA signal can induce multiple and severe developmental malformations. The evidence connecting human syndromes to reduced RA signaling is presented here and the resulting phenotypes are compared to FASD. Available data suggest that competition between ethanol clearance and RA biosynthesis is a major etiological component in FASD.

Prenatal Alcohol Exposure Causes Adverse Cardiac Extracellular Matrix Changes and Dysfunction in Neonatal Mice

Fetal alcohol syndrome (FAS) is the most severe condition of fetal alcohol spectrum disorders (FASD) and is associated with congenital heart defects. However, more subtle defects such as ventricular wall thinning and cardiac compliance may be overlooked in FASD. Our studies focus on the role of cardiac fibroblasts in the neonatal heart, and how they are affected by prenatal alcohol exposure (PAE). We hypothesize that PAE affects fibroblast function contributing to dysregulated collagen synthesis, which leads to cardiac dysfunction. To investigate these effects, pregnant C57/BL6 mice were intraperitoneally injected with 2.9 g EtOH/kg dose to achieve a blood alcohol content of approximately 0.35 on gestation days 6.75 and 7.25. Pups were sacrificed on neonatal day 5 following echocardiography measurements of left ventricular (LV) chamber dimension and function. Hearts were used for primary cardiac fibroblast isolation or protein expression analysis. PAE animals had thinner ventricular walls than saline exposed animals, which was associated with increased LV wall stress and decreased ejection fraction. In isolated fibroblasts, PAE decreased collagen I/III ratio and increased gene expression of profibrotic markers, including α-smooth muscle actin and lysyl oxidase. Notch1 signaling was assessed as a possible mechanism for fibroblast activation, and indicated that gene expression of Notch1 receptor and downstream Hey1 transcription factor were increased. Cardiac tissue analysis revealed decreased collagen I/III ratio and increased protein expression of α-smooth muscle actin and lysyl oxidase. However, Notch1 signaling components decreased in whole heart tissue. Our study demonstrates that PAE caused adverse changes in the cardiac collagen profile and a decline in cardiac function in the neonatal heart.

Exon level machine learning analyses elucidate novel candidate miRNA targets in an avian model of fetal alcohol spectrum disorder

Gestational alcohol exposure causes fetal alcohol spectrum disorder (FASD) and is a prominent cause of neurodevelopmental disability. Whole transcriptome sequencing (RNA-Seq) offer insights into mechanisms underlying FASD, but gene-level analysis provides limited information regarding complex transcriptional processes such as alternative splicing and non-coding RNAs. Moreover, traditional analytical approaches that use multiple hypothesis testing with a false discovery rate adjustment prioritize genes based on an adjusted p-value, which is not always biologically relevant. We address these limitations with a novel approach and implemented an unsupervised machine learning model, which we applied to an exon-level analysis to reduce data complexity to the most likely functionally relevant exons, without loss of novel information. This was performed on an RNA-Seq paired-end dataset derived from alcohol-exposed neural fold-stage chick crania, wherein alcohol causes facial deficits recapitulating those of FASD. A principal component analysis along with k-means clustering was utilized to extract exons that deviated from baseline expression. This identified 6857 differentially expressed exons representing 1251 geneIDs; 391 of these genes were identified in a prior gene-level analysis of this dataset. It also identified exons encoding 23 microRNAs (miRNAs) having significantly differential expression profiles in response to alcohol. We developed an RDAVID pipeline to identify KEGG pathways represented by these exons, and separately identified predicted KEGG pathways targeted by these miRNAs. Several of these (ribosome biogenesis, oxidative phosphorylation) were identified in our prior gene-level analysis. Other pathways are crucial to facial morphogenesis and represent both novel (focal adhesion, FoxO signaling, insulin signaling) and known (Wnt signaling) alcohol targets. Importantly, there was substantial overlap between the exomes themselves and the predicted miRNA targets, suggesting these miRNAs contribute to the gene-level expression changes. Our novel application of unsupervised machine learning in conjunction with statistical analyses facilitated the discovery of signaling pathways and miRNAs that inform mechanisms underlying FASD.

Preconception paternal alcohol exposure exerts sex-specific effects on offspring growth and long-term metabolic programming

BACKGROUND

Although clinical data support an association between paternal alcohol use and deficits in child neurocognitive development, the relationship between paternal drinking and alcohol-induced growth phenotypes remains challenging to define. Using an established mouse model of chronic exposure, previous work by our group has linked preconception paternal alcohol use to sex-specific patterns of fetal growth restriction and placental dysfunction. The aim of the present study was to investigate the long-term impact of chronic preconception paternal alcohol use on offspring growth and metabolic programming.

RESULTS

Preconception paternal alcohol exposure induced a prolonged period of fetal gestation and an increased incidence of intrauterine growth restriction, which affected the male offspring to a greater extent than the females. While the female offspring of ethanol-exposed males were able to match the body weights of the controls within the first 2 weeks of postnatal life, male offspring continued to display an 11% reduction in weight at 5 weeks of age and a 6% reduction at 8 weeks of age. The observed growth deficits associated with insulin hypersensitivity in the male offspring, while in contrast, females displayed a modest lag in their glucose tolerance test. These metabolic defects were associated with an up-regulation of genes within the pro-fibrotic TGF-β signaling pathway and increased levels of cellular hydroxyproline within the livers of the male offspring. We observed suppressed cytokine profiles within the liver and pancreas of both the male and female offspring, which correlated with the up-regulation of genes in the LiverX/RetinoidX/FarnesoidX receptor pathways. However, patterns of gene expression were highly variable between the offspring of alcohol-exposed sires. In the adult offspring of alcohol-exposed males, we did not observe any differences in the allelic expression of Igf2 or any other imprinted genes.

CONCLUSIONS

The impact of paternal alcohol use on child development is poorly explored and represents a significant gap in our understanding of the teratogenic effects of ethanol. Our studies implicate paternal exposure history as an additional and important modifier of alcohol-induced growth phenotypes and challenge the current maternal-centric exposure paradigm.

Deletion of TLR-4 attenuates fetal alcohol exposure-induced gene expression and social interaction deficits

Fetal alcohol spectrum disorders (FASD) are associated with social interaction behavior and gastrointestinal (GI) abnormalities. These abnormal behaviors and GI abnormalities overlap with autism spectrum disorder (ASD). We investigated the effect of fetal alcohol exposure (FAE) on social interaction deficits (hallmark of autism) in mice. Evidence indicates that exogenous lipopolysaccharide (LPS) administration during gestation induces autism-like behavior in the offspring. LPS regulates the expression of genes underlying differentiation, immune function, myelination, and synaptogenesis in fetal brain by the LPS receptor, TLR-4-dependent mechanism. In this study, we evaluated the role of TLR-4 in FAE-induced social behavior deficit. WT and TLR4^-/- pregnant mice were fed Lieber-DeCarli liquid diet with or without ethanol. The control group was pair-fed with an isocaloric diet. Social behavior was tested in the adult offspring at postnatal day 60. Frontal cortex mRNA expression of autistic candidate genes (Ube3a, Gabrb3, Mecp2) and inflammatory cytokine genes (IL-1β, IL-6, TNF-α) were measured by RT-qPCR. Adult male offspring of ethanol-fed WT dams showed low birth weight compared to offspring of pair-fed WT dams. However, their body weights at adulthood were greater compared to the body weights of offspring of pair-fed WT dams. There were no body weight differences in offspring of TLR4^-/- dams. Social interaction deficit was observed only in male offspring of ethanol-fed WT dams, but it was not observed in both male and female offspring of ethanol-fed TLR4^-/- dams. Expressions of autism candidate genes, Gabrb3 and Ube3a, were elevated, while that of the Mecp2 gene was suppressed in the frontal cortex of male, but not female, offspring of ethanol-fed WT mice. The expressions of inflammatory cytokine genes, IL-1β, IL-6, and TNF-α, were also significantly increased in the frontal cortex of male, but not female, offspring of ethanol-fed dams. The changes in the expression of autistic and cytokine genes were unaffected in the offspring of ethanol-fed TLR4^-/- dams. These data also indicate that TLR4 mediates FAE-induced changes in social interactions and gene expression in brain, suggesting that ethanol-induced LPS absorption from the maternal gut may be involved in gene expression changes in the fetal brain.

DNA methylation as a predictor of fetal alcohol spectrum disorder

Background

Fetal alcohol spectrum disorder (FASD) is a developmental disorder that manifests through a range of cognitive, adaptive, physiological, and neurobiological deficits resulting from prenatal alcohol exposure. Although the North American prevalence is currently estimated at 2-5%, FASD has proven difficult to identify in the absence of the overt physical features characteristic of fetal alcohol syndrome. As interventions may have the greatest impact at an early age, accurate biomarkers are needed to identify children at risk for FASD. Building on our previous work identifying distinct DNA methylation patterns in children and adolescents with FASD, we have attempted to validate these associations in a different clinical cohort and to use our DNA methylation signature to develop a possible epigenetic predictor of FASD.

Methods

Genome-wide DNA methylation patterns were analyzed using the Illumina HumanMethylation450 array in the buccal epithelial cells of a cohort of 48 individuals aged 3.5-18 (24 FASD cases, 24 controls). The DNA methylation predictor of FASD was built using a stochastic gradient boosting model on our previously published dataset FASD cases and controls (GSE80261). The predictor was tested on the current dataset and an independent dataset of 48 autism spectrum disorder cases and 48 controls (GSE50759).

Results

We validated findings from our previous study that identified a DNA methylation signature of FASD, replicating the altered DNA methylation levels of 161/648 CpGs in this independent cohort, which may represent a robust signature of FASD in the epigenome. We also generated a predictive model of FASD using machine learning in a subset of our previously published cohort of 179 samples (83 FASD cases, 96 controls), which was tested in this novel cohort of 48 samples and resulted in a moderately accurate predictor of FASD status. Upon testing the algorithm in an independent cohort of individuals with autism spectrum disorder, we did not detect any bias towards autism, sex, age, or ethnicity.

Conclusion

These findings further support the association of FASD with distinct DNA methylation patterns, while providing a possible entry point towards the development of epigenetic biomarkers of FASD.

[Fetal alcohol syndrome is not the only consequence of prenatal alcohol exposure]

Fetal alcohol syndrome is not the only consequence of prenatal alcohol exposure  The prevalence of fetal alcohol syndrome and fetal alcohol spectrum disorders in larger communities in USA is now updated to 0.4 % and 4.8 % respectively. Affected individuals bear witness to disease symptoms from many organ systems in addition to the brain and behavioural dysfunctions. In the light of modern epigenetic research, early alcohol exposure appears to play a hidden role in fetal reprogramming. The underlying mechanisms explain the »developmental origin of health and disease«, which has an impact on complex interactions between genome, environment and epigenetics.

Prenatal alcohol exposure inducing the apoptosis of mossy cells in hippocampus of SMS2-/- mice

In order to understand the mechanisms of alcohol-induced neuroapoptosis through the ceramide pathway, sphingomyelin synthase 2 knockout (SMS2-/-) mice were used to make the prenatal alcohol exposure model, and the role of ceramide regulation on alcohol-induced neuroapoptosis was studied in the offspring. Initially the levels of serum sphingomyelin (SM) were detected with enzymatic method in P0 pups after alcohol exposure in parents. Then the apoptosis of mossy cells in the offspring hippocampus was investigated after prenatal alcohol exposure with immunohistochemistry and TUNEL assay. Finally the expression of activated Caspase 8 and activated Caspase 3 in the offspring hippocampus was detected with Western blot analysis. Our results showed that SM levels were down-regulated in a dose-dependent manner (p<0.05) after prenatal alcohol exposure in wild-type (WT) and SMS2-/- pups. However, SM levels of serum in SMS2-/- pups were significantly lower than that in WT pups (p<0.01). Furthermore, we found that mossy cells were very sensitive to alcohol-induced neuroapoptosis. In both WT pups and SMS2-/- pups, the number of apoptotic mossy cells in the hippocampus increased after prenatal alcohol exposure in a dose dependent manner (p<0.05) and decreased with the growing age. Compared with WT pups, the number of apoptotic mossy cells in the hippocampus of SMS2-/- pups increased (p<0.05). Western blotting showed that the expression of activated Caspase 8 and activated Caspase 3 of hippocampal tissue in WT pups and SMS2-/- pups increases after prenatal alcohol exposure, consistent with results from TUNEL assay and immunocytochemistry. Our study suggests that mossy cells may be the easily attacked cells for fetal alcohol spectrum disorder (FASD), and ceramide is involved in the alcohol-induced neural apoptosis. The mechanism probably lies in the accumulated ceramide in SMS2 mice, and the increase of activated Caspase 8 and Caspase 3 promotes alcohol-induced neuroapoptosis.

DNA methyltransferase expressions in Japanese rice fish (Oryzias latipes) embryogenesis is developmentally regulated and modulated by ethanol and 5-azacytidine

We aimed to investigate the impact of the epigenome in inducting fetal alcohol spectrum disorder (FASD) phenotypes in Japanese rice fish embryogenesis. One of the significant events in epigenome is DNA methylation which is catalyzed by DNA methyltransferase (DNMT) enzymes. We analyzed DNMT enzyme mRNA expressions in Japanese rice fish development starting from fertilized eggs to hatching and also in embryos exposed for first 48h of development either to ethanol (300mM) or to 5-azacytidine (5-azaC; 2mM), an inhibitor of DNMT enzyme activity. As observed in FASD phenotypes, 5-azaC exposure was able to induce microcephaly and craniofacial cartilage deformities in Japanese rice fish. Moreover, we have observed that expression of DNMTs (dnmt1, dnmt3aa, and dnmt3bb.1) are developmentally regulated; high mRNA copies were found in early stages (1-2day-post-fertilization, dpf), followed by gradual reduction until hatched. In ethanol-treated embryos, compared to controls, dnmt1 mRNA is in reduced level in 2dpf and in enhanced level in 6dpf embryos. While dnmt3aa and 3bb.1 remained unaltered. In contrast, embryos exposed to 5-azaC have an enhanced level of dnmt1 and dnmt3bb.1 mRNAs both in 2 and 6dpf embryos while dnmt3aa is enhanced only in 6dpf embryos. Moreover, endocannabinoid receptor 1a (cnr1a) mRNA which was found to be reduced by ethanol remained unaltered and cnr1b and cnr2 mRNAs, which were remained unaltered by ethanol, were increased significantly by 5-azaC in 6dpf embryos. This study indicates that the craniofacial defects observed in FASD phenotypes are the results of dysregulations in DNMT expressions.

Impaired ILK Function Is Associated with Deficits in Hippocampal Based Memory and Synaptic Plasticity in a FASD Rat Model

Fetal Alcohol Spectrum Disorder (FASD) is an umbrella term that encompasses a wide range of anatomical and behavioral problems in children who are exposed to alcohol during the prenatal period. There is no effective treatment for FASD, because of lack of complete characterization of the cellular and molecular mechanisms underlying this condition. Alcohol has been previously characterized to affect integrins and growth factor signaling receptors. Integrin Linked Kinase (ILK) is an effector of integrin and growth-factor signaling which regulates various signaling processes. In FASD, a downstream effector of ILK, Glycogen Synthase Kinase 3β (GSK3β) remains highly active (reduced Ser9 phosphorylation). GSK3β has been known to modulate glutamate receptor trafficking and channel properties. Therefore, we hypothesize that the cognitive deficits accompanying FASD are associated with impairments in the ILK signaling pathway. Pregnant Sprague Dawley rats consumed a "moderate" amount of alcohol throughout gestation, or a calorie-equivalent sucrose solution. Contextual fear conditioning was used to evaluate memory performance in 32-33-day-old pups. Synaptic plasticity was assessed in the Schaffer Collateral pathway, and hippocampal protein lysates were used to evaluate ILK signaling. Alcohol exposed pups showed impaired contextual fear conditioning, as compared to control pups. This reduced memory performance was consistent with decrease in LTP as compared to controls. Hippocampal ILK activity and GSK3β Ser21/9 phosphorylation were significantly lower in alcohol-exposed pups than controls. Increased synaptic expression of GluR2 AMPA receptors was observed with immunoprecipitation of post-synaptic density protein 95 (PSD95). Furthermore, immunoprecipitation of ILK revealed a decreased interaction with GluR2. The ILK pathway appears to play a significant role in memory and synaptic plasticity impairments in FASD rats. These impairments appear to be mediated by reduced GSK3β regulation and increased synaptic stabilization of the calcium-impermeable GluR2 AMPA receptors.

Genetic absence of nNOS worsens fetal alcohol effects in mice. I: behavioral deficits

BACKGROUND

Alcohol abuse during pregnancy often induces neuropsychological problems in the offspring, including learning disorders, attention deficits, and behavior problems, all of which are prominent components of fetal alcohol spectrum disorders (FASD). However, not all children who were exposed to alcohol in utero are equally affected by it. While some children have major deficits, others are spared. This unequal vulnerability is likely due largely to differences in fetal genetics. Some fetuses appear to have certain genotypes that make them much more prone to FASD. However, to date, no gene has been identified that worsens alcohol-induced brain dysfunction. Nitric oxide (NO) is a gaseous molecule that can protect developing neurons against alcohol-induced death. In the brain, NO is produced by neuronal nitric oxide synthase (nNOS). In this study, we examined whether homozygous mutation of the nNOS gene in mice worsens the behavioral deficits of developmental alcohol exposure.

METHODS

Wild-type and nNOS(-/-) mice received alcohol (0.0, 2.2, or 4.4 mg/g) daily over postnatal days (PDs) 4 to 9. Beginning on PD 85, the mice underwent a series of behavioral tests, including open field activity, the Morris water maze, and paired pulse inhibition.

RESULTS

For the wild-type mice, alcohol impaired performance only in the water maze. In contrast, for the nNOS(-/-) mice, alcohol impaired performance on all 3 tasks. Furthermore, the nNOS(-/-) mice were substantially more impaired than wild-type mice in their performance on all 3 of the behavioral tests and at both the low (2.2) and high (4.4) doses of alcohol.

CONCLUSIONS

Targeted disruption of the nNOS gene worsens the behavioral impact of developmental alcohol exposure and allows alcohol-induced learning problems to emerge that are not seen in wild type. This is the first demonstration that a specific genotype can interact with alcohol to worsen functional brain deficits in an animal model of FASD.

Investigating the fetal and postnatal effects of paternal alcohol exposure in mouse offspring: a review

To further elucidate the possible effects of paternal alcohol exposure on fetal and post-natal development, Lee et al. conducted an experimental animal study from which potential transgenerational consequences of paternal alcohol exposure on mouse offspring were explored. The authors concluded that paternal alcohol consumption likely poses some risk to those developing offspring. However, the authors' analysis of the incidence of fetal abnormalities may be misleading. The incidence of abnormality for each treatment group was calculated by dividing the number of abnormalities by the total number of dames. This approach to presenting the data is misrepresentative, because if a dame were carrying one abnormally developed fetus out of a litter of, say, 16, the entire litter would be captured as an "abnormality" in the calculation of incidence.  

Fetal alcohol spectrum disorders and cognitive functions of young children

Fetal alcohol spectrum disorder (FASD) is one of the main causes of mental retardation worldwide. Nearly 1% of children in North America are affected from antenatal exposure to ethanol. Its economic burden in industrialized countries is increasing. It is estimated that, in the United States, 4.0 billion dollars are annually expended in the treatment and rehabilitation of these patients. As a pathologic entity, they present with a broad symptomatology. Fetal alcohol syndrome (FAS) is the most readily recognized clinical manifestation of these disorders. Various factors seem to contribute in the pathogenesis of FASD-related cognitive disorders. During the last 20 years, several potential pretranslational and posttranslational factors have been extensively studied in various experimental animal models. Research has specifically focused on several neurotransmitters, insulin resistance, alterations of the hypothalamic-pituitary-adrenal (HPA) axis, abnormal glycosylation of several proteins, oxidative stress, nutritional antioxidants, and various epigenetic factors. The purpose of the present review is to summarize the clinical manifestations of this disorder during childhood and adolescence and to summarize the possible pathophysiologic and epigenetic pathways that have been implicated in the pathophysiology of FASD.

Parental binge alcohol abuse alters F1 generation hypothalamic gene expression in the absence of direct fetal alcohol exposure

Adolescent binge alcohol exposure has long-lasting effects on the expression of hypothalamic genes that regulate the stress response, even in the absence of subsequent adult alcohol exposure. This suggests that alcohol can induce permanent gene expression changes, potentially through epigenetic modifications to specific genes. Epigenetic modifications can be transmitted to future generations therefore, and in these studies we investigated the effects of adolescent binge alcohol exposure on hypothalamic gene expression patterns in the F1 generation offspring. It has been well documented that maternal alcohol exposure during fetal development can have devastating neurological consequences. However, less is known about the consequences of maternal and/or paternal alcohol exposure outside of the gestational time frame. Here, we exposed adolescent male and female rats to a repeated binge EtOH exposure paradigm and then mated them in adulthood. Hypothalamic samples were taken from the offspring of these animals at postnatal day (PND) 7 and subjected to a genome-wide microarray analysis followed by qRT-PCR for selected genes. Importantly, the parents were not intoxicated at the time of mating and were not exposed to EtOH at any time during gestation therefore the offspring were never directly exposed to EtOH. Our results showed that the offspring of alcohol-exposed parents had significant differences compared to offspring from alcohol-naïve parents. Specifically, major differences were observed in the expression of genes that mediate neurogenesis and synaptic plasticity during neurodevelopment, genes important for directing chromatin remodeling, posttranslational modifications or transcription regulation, as well as genes involved in regulation of obesity and reproductive function. These data demonstrate that repeated binge alcohol exposure during pubertal development can potentially have detrimental effects on future offspring even in the absence of direct fetal alcohol exposure.

Developmental regulation of neuroligin genes in Japanese ricefish (Oryzias latipes) embryogenesis maintains the rhythm during ethanol-induced fetal alcohol spectrum disorder

Although prenatal alcohol exposure is the potential cause of fetal alcohol spectrum disorder (FASD) in humans, the molecular mechanism(s) of FASD is yet unknown. We have used Japanese ricefish (Oryzias latipes) embryogenesis as an animal model of FASD and reported that this model has effectively generated several phenotypic features in the cardiovasculature and neurocranial cartilages by developmental ethanol exposure which is analogous to human FASD phenotypes. As FASD is a neurobehavioral disorder, we are searching for a molecular target of ethanol that alters neurological functions. In this communication, we have focused on neuroligin genes (nlgn) which are known to be active at the postsynaptic side of both excitatory and inhibitory synapses of the central nervous system. There are six human NLGN homologs of Japanese ricefish reported in public data bases. We have partially cloned these genes and analyzed their expression pattern during normal development and also after exposing the embryos to ethanol. Our data indicate that the expression of all six nlgn genes in Japanese ricefish embryos is developmentally regulated. Although ethanol is able to induce developmental abnormalities in Japanese ricefish embryogenesis comparable to the FASD phenotypes, quantitative real-time PCR (qPCR) analysis of nlgn mRNAs indicate unresponsiveness of these genes to ethanol. We conclude that the disruption of the developmental rhythm of Japanese ricefish embryogenesis by ethanol that leads to FASD may not affect the nlgn gene expression at the message level.

[Brain-derived neurotrophic factor: the influence on the genetically and epigenetically determined behavioral disorders]

Recent investigations have widened the knowledge concerning the brain derived neurotrophic factor (BDNF). The review concentrates on the data of literature and original data of authors on BDNF effects on genetically and epigenetically defined behavioral disorders. Specifically it describes the implication of the brain serotonergic system and the role of genotype in the neuroprotective effects of BDNF. The review provides evidence that: 1) genes encoding key elements of the brain serotonergic system (tryptophan hydroxylase-2, 5-HT1A and 5-HT2A receptors) are implicated in the effect ofBDNF; 2) acute central administration of BDNF produced long-term ameliorative effects on some animal models of genetically defined behavior disorders; 3) BDNF decreased behavioral disorders induced by prenatal stress and ethanol exposure and may play an important role in the treatment of epigenetically defined pathological behavior.

Commonality in Down and fetal alcohol syndromes

BACKGROUND

Down syndrome (DS) and Fetal Alcohol Syndrome (FAS) are two leading causes of birth defects with phenotypes ranging from craniofacial abnormalities to cognitive impairment. Despite different origins, we report that in addition to sharing many phenotypes, DS and FAS may have common underlying mechanisms of development.

METHODS

Literature was surveyed for DS and FAS as well as mouse models. Gene expression and apoptosis were compared in embryonic mouse models of DS and FAS by qPCR, immunohistochemical and immunoflurorescence analyses. The craniometry was examined using MicroCT at postnatal day 21.

RESULTS

A literature survey revealed over 20 comparable craniofacial and structural deficits in both humans with DS and FAS and corresponding mouse models. Similar phenotypes were experimentally found in pre- and postnatal craniofacial and neurological tissues of DS and FAS mice. Dysregulation of two genes, Dyrk1a and Rcan1, key to craniofacial and neurological precursors of DS, was shared in craniofacial precursors of DS and FAS embryos. Increased cleaved caspase 3 expression was also discovered in comparable regions of the craniofacial and brain precursors of DS and FAS embryos. Further mechanistic studies suggested overexpression of trisomic Ttc3 in DS embyros may influence nuclear pAkt localization and cell survival.

CONCLUSIONS

This first and initial study indicates that DS and FAS share common dysmorphologies in humans and animal models. This work also suggests common mechanisms at cellular and molecular levels that are disrupted by trisomy or alcohol consumption during pregnancy and lead to craniofacial and neurological phenotypes associated with DS or FAS.

Epigenetic medicine and fetal alcohol spectrum disorders

Epigenetic medicine is still in its infancy. To date, only a handful of diseases have documented epigenetic correlates upstream of gene regulation including cancer, developmental syndromes and late-onset diseases. The finding that epigenetic markers are dynamic and heterogeneous at tissue and cellular levels, combined with recent identification of a new form of functionally distinct DNA methylation has opened a wider window for investigators to pry into the epigenetic world. It is anticipated that many diseases will be elucidated through this epigenetic inquiry. In this review, we discuss the normal course of DNA methylation during development, taking alcohol as a demonstrator of the epigenetic impact of environmental factors in disease etiology, particularly the growth retardation and neurodevelopmental deficits of fetal alcohol spectrum disorders.

Alcohol-induced behavioural problems in fetal alcohol spectrum disorders versus confounding behavioural problems

Prenatal alcohol exposure is strongly associated with disruptive behaviour in childhood and antisocial behaviour later in life. There are numerous confounding risk factors in the lives of alcohol-abusing mothers that may contribute to the behaviour problems seen in their children, rather than direct brain injury by alcohol. In fact, many of these additional environmental and genetic risk factors for childhood behaviour problems co-occur with prenatal alcohol exposure and affect the same child, creating a confluence of risk. As a result, one cannot with any certainty attribute behaviour problems in an individual child to prenatal alcohol exposure. This has important clinical and legal implications.

Strain-specific vulnerability to alcohol exposure in utero via hippocampal parent-of-origin expression of deiodinase-III

Prenatal exposure to alcohol is thought to be the most prevalent nongenetic cause of a wide range of neurodevelopmental deficits. Insufficient thyroid hormone levels are one mechanism that hampers development of the alcohol-exposed brain, and we hypothesized that altered dosage of the imprinted thyroid hormone-inactivating gene deiodinase-III (Dio3) is responsible. To follow parent-of-origin allelic expression of Dio3 in the fetal and adult offspring of alcohol-consuming and control dams, we reciprocally crossed 2 polymorphic rat strains. In the frontal cortex, prenatal alcohol exposure altered imprinting patterns and total expression of Dio3 in the fetus and produced a permanent hypothyroid milieu in the adult. In the hippocampus, alcohol affected the paternal and total expression of Dio3 in the fetus and in the adult male, where thyroid hormone levels were concomitantly increased. Hippocampus-dependent behavioral deficits were identified exclusively in males, suggesting they are dependent on aberrant allelic Dio3 expression. None of these effects were observed in offspring of the reciprocal cross. Thus, genetic background and sex modify vulnerability to prenatal alcohol via brain region-specific expression of Dio3. This finding implies that phenotypic heterogeneity in human fetal alcohol spectrum disorder can be linked to genetic vulnerability in affected brain regions.

Maternal risk factors for fetal alcohol spectrum disorders: not as simple as it might seem

Gathering information about drinking during pregnancy is one of the most difficult aspects of studying fetal alcohol spectrum disorders (FASD). This information is critical to linking specific risk factors to any particular diagnosis within the FASD continuum. This article reviews highlights from the literature on maternal risk factors for FASD and illustrates that maternal risk is multidimensional, including factors related to quantity, frequency, and timing of alcohol exposure; maternal age; number of pregnancies; number of times the mother has given birth; the mother's body size; nutrition; socioeconomic status; metabolism; religion; spirituality; depression; other drug use; and social relationships. More research is needed to more clearly define what type of individual behavioral, physical, and genetic factors are most likely to lead to having children with FASD.

Paternal genetic contribution influences fetal vulnerability to maternal alcohol consumption in a rat model of fetal alcohol spectrum disorder

BACKGROUND

Fetal alcohol exposure causes in the offspring a collection of permanent physiological and neuropsychological deficits collectively termed Fetal Alcohol Spectrum Disorder (FASD). The timing and amount of exposure cannot fully explain the substantial variability among affected individuals, pointing to genetic influences that mediate fetal vulnerability. However, the aspects of vulnerability that depend on the mother, the father, or both, are not known.

METHODOLOGY/PRINCIPAL FINDINGS

Using the outbred Sprague-Dawley (SD) and inbred Brown Norway (BN) rat strains as well as their reciprocal crosses, we administered ethanol (E), pair-fed (PF), or control (C) diets to the pregnant dams. The dams' plasma levels of free thyroxine (fT4), triiodothyronine (T3), free T3 (fT3), and thyroid stimulating hormone (TSH) were measured to elucidate potential differences in maternal thyroid hormonal environment, which affects specific aspects of FASD. We then compared alcohol-exposed, pair fed, and control offspring of each fetal strain on gestational day 21 (G21) to identify maternal and paternal genetic effects on bodyweight and placental weight of male and female fetuses.

CONCLUSIONS

SD and BN dams exhibited different baseline hypothalamic-pituitary-thyroid function. Moreover, the thyroid function of SD dams was more severely affected by alcohol consumption while that of BN dams was relatively resistant. This novel finding suggests that genetic differences in maternal thyroid function are one source of maternal genetic effects on fetal vulnerability to FASD. The fetal vulnerability to decreased bodyweight after alcohol exposure depended on the genetic contribution of both parents, not only maternal contribution as previously thought. In contrast, the effect of maternal alcohol consumption on placental weight was consistent and not strain-dependent. Interestingly, placental weight in fetuses with different paternal genetic contributions exhibited opposite responses to caloric restriction (pair feeding). In summary, these novel findings demonstrate both maternal and paternal genetic contributions to in utero vulnerability to alcohol, refining our understanding of the genetically-based heterogeneity seen in human FASD.

Alcohol abuse in pregnant women: effects on the fetus and newborn, mode of action and maternal treatment

Offspring of mothers using ethanol during pregnancy are known to suffer from developmental delays and/or a variety of behavioral changes. Ethanol, may affect the developing fetus in a dose dependent manner. With very high repetitive doses there is a 6-10% chance of the fetus developing the fetal alcoholic syndrome manifested by prenatal and postnatal growth deficiency, specific craniofacial dysmorphic features, mental retardation, behavioral changes and a variety of major anomalies. With lower repetitive doses there is a risk of "alcoholic effects" mainly manifested by slight intellectual impairment, growth disturbances and behavioral changes. Binge drinking may impose some danger of slight intellectual deficiency. It is advised to offer maternal abstinence programs prior to pregnancy, but they may also be initiated during pregnancy with accompanying close medical care. The long term intellectual outcome of children born to ethanol dependent mothers is influenced to a large extent by the environment in which the exposed child is raised.

Alcohol dehydrogenase 1B genotype and fetal alcohol syndrome: a HuGE minireview

Fetal alcohol syndrome (FAS), 1 of the most common developmental disabilities in the United States, occurs at a rate of 0.5-2.0:1000 live births. Animal model, family, and twin studies suggest a genetic component to FAS susceptibility. Alcohol dehydrogenases (ADHs) catalyze the rate-limiting step in alcohol metabolism. Studies of genetic associations with FAS have focused on the alcohol dehydrogenase 1B (ADH1B) gene, comparing mothers and children with the alleles ADH1B*2 or ADH1B*3, associated with faster ethanol metabolism, with those homozygous for ADH1B*1. While most studies have found a protective effect for genotypes containing ADH1B*2 or ADH1B*3, results have been conflicting, and further investigation into the association between the ADH1B genotype and FAS is needed. Whether increased alcohol intake accounts for the elevated risk reported for the ADH1B*1/ADH1B*1 genotype should be addressed, and future studies would benefit from consistent case definitions, enhanced exposure measurements, larger sample sizes, and careful study design.

Reprogramming of genetic networks during initiation of the Fetal Alcohol Syndrome

Fetal Alcohol Spectrum Disorders (FASD) are birth defects that result from maternal alcohol use. We used a non a priori approach to prioritize candidate pathways during alcohol-induced teratogenicity in early mouse embryos. Two C57BL/6 substrains (B6J, B6N) served as the basis for study. Dosing pregnant dams with alcohol (2x 2.9 g/kg ethanol spaced 4 hr on day 8) induced FASD in B6J at a higher incidence than B6N embryos. Counter-exposure to PK11195 (4 mg/kg) significantly protected B6J embryos but slightly promoted FASD in B6N embryos. Microarray transcript profiling was performed on the embryonic headfold 3 hr after the first maternal alcohol injection (GEO data series accession GSE1074). This analysis revealed metabolic and cellular reprogramming that was substrain-specific and/or PK11195-dependent. Mapping ethanol-responsive KEGG (Kyoto Encyclopedia of Genes and Genomes) pathways revealed down-regulation of ribosomal proteins and proteasome, and up-regulation of glycolysis and pentose phosphate pathway in B6N embryos; and significant up-regulation of tight junction, focal adhesion, adherens junction, and regulation of the actin cytoskeleton (and near-significant up-regulation of Wnt signaling and apoptosis) pathways in both substrains. Expression networks constructed computationally from these altered genes identified entry points for EtOH at several hubs (MAPK1, ALDH3A2, CD14, PFKM, TNFRSF1A, RPS6, IGF1, EGFR, PTEN) and for PK11195 at AKT1. Our findings are consistent with the growing view that developmental exposure to alcohol alters common signaling pathways linking receptor activation to cytoskeletal reorganization. The programmatic shift in cell motility and metabolic capacity further implies cell signals and responses that are integrated by the mitochondrial recognition site for PK11195.

[An unusual case of duplication of the spinal canal]

We describe here a very rare congenital malformation, in which the vertebra Th 9 to 11 were divided into independent bodies and neural arches. The vertebral canal contained the spinal cord, whereas the space between bodies and arches was filled by nerve roots and a central remnant cord, not clearly connected to the main spinal cord. This malformation was considered as related to a fetal alcohol syndrome, with craniofacial and genitourinary abnormalities. The authors analyze, moreover the possible role of abnormal Sonic Hedgehog gene patterning in the pathogeny of this complex malformative sequence.

Health-related effects of genetic variations of alcohol-metabolizing enzymes in African Americans

Alcohol metabolism involves two key enzymes-alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH). There are several types of ADH and ALDH, each of which may exist in several variants (i.e., isoforms) that differ in their ability to break down alcohol and its toxic metabolite acetaldehyde. The isoforms are encoded by different gene variants (i.e., alleles) whose distribution among ethnic groups differs. One variant of ADH is ADH1B, which is encoded by several alleles. An allele called ADH1 B*3 is unique to people of African descent and certain Native American tribes. This allele is associated with more rapid breakdown of alcohol, leading to a transient accumulation of acetaldehyde. African Americans carrying this allele are less likely to have a family history of alcoholism and experience a less rewarding subjective response to alcohol. Moreover, children of mothers with this allele are less vulnerable to alcohol-related birth defects. The enzyme ALDH1 also is encoded by several alleles. Two of these alleles that are found in African Americans-ALDH1 A1 *2 and ALDH1A1 *3--may be associated with a reduced risk of alcoholism.

Regulation of cardiac mitochondrial monolysocardiolipin acyltransferase activity and expression during development and in fetal alcohol syndrome

Fetal alcohol syndrome is a serious developmental disorder and exposure of the fetal heart to alcohol results in disturbances in the biochemistry of all cellular substructures. Mitochondrial effects include diminished respiratory function and physical alteration of the membrane secondary to interaction of ethanol with the hydrophobic region of the bilayer. Cardiolipin is a major mitochondrial membrane phospholipid in the heart and plays an important role in the function of mitochondrial enzymes involved in cellular respiration. We examined the activity of cardiac monolysocardiolipin acyltransferase, a key enzyme responsible for the molecular remodelling of cardiolipin with new fatty acids, in the newborn and adult rat and in new born rats that were exposed to alcohol in utero. Cardiac monolysocardiolipin acyltransferase activities were 57% lower (p < 0.05) in adult rats compared to newborn rats. Cardiac mitochondrial monolysocardiolipin acyltransferase activities were 36% lower (p < 0.05) in newborn rats that were exposed to alcohol in utero and this was due to reduced mitochondrial monolysocardiolipin acyltransferase expression. The results indicate that cardiac mitochondrial monolysocardiolipin acyltransferase activity declines during postnatal development in the rat and that in utero exposure to alcohol inhibits cardiac monolysocardiolipin acyltransferase activity and expression.

Fetal alcohol spectrum disorders: a practical clinical approach to diagnosis

In utero exposure to alcohol can have numerous adverse effects on a developing fetus. These effects represent a spectrum of structural anomalies and neurocognitive and behavioral disabilities that have recently been termed fetal alcohol spectrum disorders (FASD). Children at the most severe end of this spectrum and displaying the complete phenotype of characteristic facial anomalies, growth retardation and developmental abnormalities of the central nervous system are defined as having fetal alcohol syndrome (FAS). While FAS is the most readily clinically recognized form of FASD, other categories within the continuum of adverse effects due to prenatal alcohol exposure are becoming better defined. These include partial fetal alcohol syndrome (PFAS), alcohol-related birth defects (ARBD) and alcohol-related neurodevelopmental disorder (ARND). As more is learned regarding the exact manifestations of alcohol on brain development, these classifications may be expanded and/or refined. Because FASD represents a major public health concern, early recognition of at-risk children is important for initiating interventional strategies. Thus, the purpose of this report is to educate practicing physicians about the recognizable phenotypes of FASD in order to accurately identify these children and implement the most appropriate management plans.

Metabolic and genetic factors contributing to alcohol induced effects and fetal alcohol syndrome

Alcohol-related damages on newborns and infants include a wide variety of complications from facial anomalies to neurodevelopmental delay, known as fetal alcohol syndrome (FAS). However, only less than 10% of women drinking alcohol during pregnancy have children with FAS. Understanding the risk factors increasing the probability for newborn exposed in utero to alcohol to develop FAS is therefore a key issue. The involvement of genetics as a one risk factor in FAS has been suggested by animal models and by molecular epidemiological studies on different populations, bearing allelic variants for those enzymes, such as ADH e CYP2E1, involved in ethanol metabolism. Indeed, one of the major factors determining the peak blood alcohol exposure to the fetus is the metabolic activity of the mother, in addition to placental and fetal metabolism, explaining, at least partially, the risk of FAS. The different rates of ethanol metabolism may be the result of genetic polymorphisms, the most relevant of which have been described in the paper.

Proceedings of the 2006 annual meeting of the Fetal Alcohol Spectrum Disorders Study Group

This article describes the proceedings of the 2006 Annual Meeting of the Fetal Alcohol Spectrum Disorders Study Group (FASDSG), which was held in Baltimore, Maryland on June 24, 2006. The meeting was held in conjunction with the annual meeting of the Research Society on Alcoholism and was supported by a grant from the National Institute on Alcohol Abuse and Alcoholism. The 2005-2006 FASDSG officers, Daniel J. Bonthius (President), Heather Carmichael Olson (Vice-President), and Jennifer Thomas (Secretary-Treasurer), organized the meeting. Nationally prominent speakers delivered plenary lectures on topics of newborn screening, ethics, and neuroscience. Selected members of the FASDSG provided brief scientific data (FASt) reports, describing new research findings. Representatives from national agencies involved in fetal alcohol syndrome (FAS) research, treatment, and prevention provided updates regarding priorities, funding, and agency activities. Presentations were also made by the 2006 Student Merit Award recipient and by the 2006 Rosett Award recipient. The meeting served as a forum for clinicians, neuroscientists, psychologists, social scientists, and other professionals to discuss recent advances in FAS research and to identify the most important gaps in the understanding of alcohol-induced teratology.