Project description:Prenatal exposure to ethanol can cause fetal alcohol spectrum disorder (FASD), a prevalent and preventable pediatric disorder. Identifying genetic risk alleles for FASD is impossible in human populations, but the Drosophila genetic model can provide insights. We analyzed changes in genome-wide gene expression in 96 wild-derived inbred fly lines after exposure to alcohol during development. We found extensive sexual dimorphism in the effect of alcohol on gene expression along with effects on adult locomotor activity and sleep. Genetic networks associated with changes in gene expression include both protein-coding and non-coding transcripts, including a female-specific module of small nucleolar RNAs that regulate pseudouridylation of ribosomal RNA. These data support a regulatory role for non-coding elements in response to developmental alcohol exposure.
Project description:The National Institute on Alcohol Abuse and Alcoholism has estimated that approximately 14 million people in the United States suffer from alcoholism. Alcohol sensitivity, the development of tolerance to alcohol and susceptibility to addiction vary in the population. Whereas environmental factors, such as stress and social experience, contribute to individual variation in sensitivity to chronic alcohol consumption, genetic factors have also been implicated. However, genetic polymorphisms that predispose to alcoholism remain largely unknown due to extensive genetic and environmental variation in human populations. Drosophila, however, allows studies on genetically identical individuals in controlled environments. Although addiction to alcohol has not been demonstrated in Drosophila, flies show responses to alcohol exposure that resemble human intoxication, including hyperactivity, loss of postural control, sedation, and exposure-dependent development of tolerance. We assessed whole-genome transcriptional responses following alcohol exposure and demonstrate immediate down-regulation of olfactory sensitivity and, concomitant with development of tolerance, altered transcription of enzymes associated with fatty acid biosynthesis. Our results identify key enzymes in conserved metabolic pathways that may contribute to human alcohol sensitivity. Keywords: Drosophila, model system, alcohol sensitivity, tolerance
Project description:Fetal alcohol exposure can lead to developmental abnormalities, intellectual disability, and behavioral changes, collectively termed fetal alcohol spectrum disorder (FASD). In 2015, the CDC found that 1 in 10 pregnant women report alcohol use and more than 3 million women in the USA are at risk of exposing their developing baby to alcohol. Identifying genetic risk alleles for FASD is challenging, since time, dose and frequency of exposure are often unknown, and phenotypic manifestations of FASD are diverse and become evident long after exposure. Drosophila melanogaster presents an excellent model to study developmental effects of alcohol exposure, because virtually unlimited numbers of individuals of the same genotype can be reared rapidly and economically under well-controlled environmental conditions without regulatory restrictions. Furthermore, flies exposed to alcohol undergo physiological and behavioral changes that resemble human alcohol-related phenotypes. Flies reared on ethanol-supplemented medium show decreased viability, reduced sensitivity to ethanol, and disrupted sleep and activity patterns. To assess alcohol-modulated gene expression in the brains of flies reared on alcohol, we performed single cell RNA sequencing and resolved cell clusters with differentially expressed genes representing distinct neuronal and glial populations. We observed extensive sexual dimorphism. Two clusters associated with glial biomarkers showed greater differential gene expression in males, whereas mushroom body-derived cells exhibited a greater degree of differential gene expression in females. Results obtained from these studies provide a blueprint for translational studies on alcohol-induced effects on gene expression in the brain that may contribute to or result from FASD in human populations.
Project description:Glial cells are central players in the pathogenesis of neurodevelopmental disorders like Fetal Alcohol Spectrum Disorder (FASD). Ethanol can modulate glial differentiation and astrocyte function imposing dramatic changes to the developing brain. Since ethanol can affect a vast number of intracellular targets and signaling pathways and many effects of early alcohol exposure on cell physiology can persist into adulthood, we tested the hypothesis that ethanol exposure in ferrets during a period equivalent to the last months of human gestation leads to a long-lasting change in astrocyte secretome in vitro. Animals were treated every other day with ethanol (5g/kg) or saline between post-natal day (P)10-30. At P31, astrocyte cultures were made and cells were submitted to stable isotope labeling by amino acids (SILAC). 24h-conditioned media of cells obtained from ethanol- or saline-treated animals (ET-CM or SAL-CM) were collected and analyzed by quantitative mass spectrometry in tandem with liquid chromatography. Here we show that 65 out of 280 quantifiable proteins displayed significant differences comparing ET-CM to SAL-CM. Among 59 proteins found reduced in ET-CM we found components of the extracellular matrix like Laminin subunits α2, α4, β1, β2 and γ1 and the proteoglycans Biglycan, Heparin Sulfate Proteoglycan 2 and Lumican. Proteins with trophic function like Insulin-Like Growth Factor Binding Protein 4, Pigment Epithelium-Derived Factor and Clusterin as well as proteins involved on modulation of proteolysis like TIMP-1 and PAI-1 were also found reduced. On the other hand, pro-synaptogeneic proteins like Thrombospondin-1, Hevin as well as the modulator of extracelular matrix expression, Angiotensinogen, were found increased in ET-CM. The analysis of interactome maps through Ingenuity Pathway Analysis demonstrated that the Amyloid beta A4 protein precursor (APP), which was found reduced in ET-CM, was previously shown to interact with ten other proteins that exhibited significant changes in the ET-CM, rendering it a suitable target for a more accurate analysis about the effects of ethanol on its biology. Taken together our results strongly suggest that early exposure to teratogens such alcohol may lead to an enduring change in astrocyte secretome, affecting mainly the expression of trophic and matricellular proteins, which in turn may lead to permanent alterations in brain function.
Project description:BackgroundPrenatal 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.ResultsWe 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.ConclusionsThere 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.
Project description:Fetal alcohol exposure at any stage of pregnancy can lead to Fetal Alcohol Spectrum Disorder (FASD), a group of life-long conditions characterized by congenital malformations, as well as cognitive, behavioral, and emotional impairments. The teratogenic effects of alcohol have long been publicized; yet fetal alcohol exposure is one of the most common preventable causes of birth defects. Currently, alcohol abstinence during pregnancy is the best and only way to prevent FASD. However, alcohol consumption remains astoundingly prevalent among pregnant women; therefore, additional measures need to be made available to help protect the developing embryo before irreparable damage is done. Maternal nutritional interventions using methyl donors have been investigated as potential preventative measures to mitigate the adverse effects of fetal alcohol exposure. Here, we show that a single acute preimplantation (E2.5; 8-cell stage) fetal alcohol exposure in mice leads to long-term FASD-like morphological phenotypes (e.g., growth restriction, brain malformations, skeletal delays) in late-gestation embryos (E18.5) and demonstrate that supplementing the maternal diet with a combination of four methyl donor nutrients, folic acid, choline, betaine, and vitamin B12, prior to conception and throughout gestation effectively reduces the incidence and severity of alcohol-induced morphological defects without altering DNA methylation status and regulation of imprinting control regions. This study clearly supports that preimplantation embryos are vulnerable to the teratogenic effects of alcohol, emphasizing the dangers of maternal alcohol consumption during early gestation, and provides a potential proactive maternal nutritional intervention to minimize FASD progression, reinforcing the importance of adequate preconception and prenatal nutrition.
Project description:Sustained or repeated exposure to sedating drugs such as alcohol triggers homeostatic adaptations in the brain that lead to the development of drug tolerance and dependence. These adaptations involve long-term changes in the transcription of drug-responsive genes as well as an epigenetic restructuring of chromosomal regions that is thought to signal and maintain the altered transcriptional state. Drug-induced epigenetic changes have been shown to be important in the long-term adaptation that leads to alcohol tolerance and dependence endophenotypes. A major constraint impeding progress is that alcohol produces a surfeit of changes in gene expression, most that may not make any meaningful contribution to the ethanol response under study. Here we used a novel genomic epigenetic approach to find genes relevant for functional alcohol tolerance by exploiting the commonalities of two chemically distinct drugs. In Drosophila melanogaster, ethanol and benzyl alcohol induce mutual cross-tolerance, indicating that they share a common mechanism for producing tolerance. We surveyed the genome-wide changes in histone acetylation that occur in response to these drugs. Each drug induces modifications in a large number of genes. The genes that respond similarly to either treatment, however, represent a subgroup enriched for genes important for the common tolerance response. Genes were functionally tested for behavioral tolerance to the sedative effects of ethanol and benzyl alcohol using mutant and inducible RNAi stocks. We identified a network of genes that are essential for the development of tolerance to sedation by alcohol. A total of six samples. Two H4Ac ChIP-chip biological replicates from heads of Drosophila (untreated, IP/input), two H4Ac ChIP-chip biological replicates from heads of Drosophila sedated with benzyl alcohol (IP_treated/IP_control), and two H4Ac ChIP-chip biological replicates from heads of Drosophila sedated with ethanol (IP_treated/IP_control) are included.