Dataset Information

Divergent and overlapping hippocampal and cerebellar transcriptome responses following developmental ethanol exposure during the secondary neurogenic period.

ABSTRACT:

Background

The developing hippocampus and cerebellum, unique among brain regions, exhibit a secondary surge in neurogenesis during the third trimester of pregnancy. Ethanol (EtOH) exposure during this period is results in a loss of tissue volume and associated neurobehavioral deficits. However, mechanisms that link EtOH exposure to teratology in these regions are not well understood. We therefore analyzed transcriptomic adaptations to EtOH exposure to identify mechanistic linkages.

Methods

Hippocampi and cerebella were microdissected at postnatal day (P)10, from control C57BL/6J mouse pups, and pups treated with 4 g/kg of EtOH from P4 to P9. RNA was isolated and RNA-seq analysis was performed. We compared gene expression in EtOH- and vehicle-treated control neonates and performed biological pathway-overrepresentation analysis.

Results

While EtOH exposure resulted in the general induction of genes associated with the S-phase of mitosis in both cerebellum and hippocampus, overall there was little overlap in differentially regulated genes and associated biological pathways between these regions. In cerebellum, EtOH additionally induced gene expression associated with the G2/M-phases of the cell cycle and sonic hedgehog signaling, while in hippocampus, EtOH-induced the pathways for ribosome biogenesis and protein translation. Moreover, EtOH inhibited the transcriptomic identities associated with inhibitory interneuron subpopulations in the hippocampus, while in the cerebellum there was a more pronounced inhibition of transcripts across multiple oligodendrocyte maturation stages.

Conclusions

These data indicate that during the delayed neurogenic period, EtOH may stimulate the cell cycle, but it otherwise results in widely divergent molecular effects in the hippocampus and cerebellum. Moreover, these data provide evidence for region- and cell-type-specific vulnerability, which may contribute to the pathogenic effects of developmental EtOH exposure.

SUBMITTER: Pinson MR

PROVIDER: S-EPMC8312515 | biostudies-literature |

REPOSITORIES: biostudies-literature

ACCESS DATA

Similar Datasets

Project description:Purpose: Fetal alcohol spectrum disorders (FASD) result from ethanol exposure to the developing fetus. FASD occur in up to 1-5% of live births in the United States and there currently is no cure. Ethanol exposure to the developing central nervous system (CNS) has profound effects on learning and memory, impulse control, and motor function, resulting from neuropathology. The purpose of the current study was to perform transcriptome analysis to evaluate the effects of early postnatal ethanol exposure in the hippocampus and cerebellum. Methods: Postnatal C57BL/6 mice were treated with 4g/kg of ethanol from P4-P9, brains were harvested 24h after the final treatment at P10, hippocampi and cerebella were microdissected, RNA was isolated, and RNASeq analysis was performed. We compared differences in gene expression, sex-dependent expression, and global biological pathways associated with disruptions in hippocampal and cerebellar genes between the ethanol and vehicle treated neonates. Results: Ethanol caused both an up and down regulation of genes associated with the hippocampus and cerebellum, which may result in the disruption of normal circuitry and maturation and growth in these brain regions. Ethanol increased the expression of genes associated with the S phase of the cell cycle in both the hippocampus and cerebellum. In the cerebellum, ethanol increased effector gene expression, and in the hippocampus, genes associated with different interneuron lineages were altered. Postnatal ethanol exposure also resulted in altered expression of genes associated with oligodendrocyte lineages and myelination, along with alterations in microglia associated genes. Conclusion: Collectively, these data indicate that ethanol has profound effects on the hippocampus and cerebellum, resulting in alterations of gene expression and biological pathways regulating neurodevelopment. These studies may have important implications concerning alcohol-induced neuropathology and the neurological effects seen across the life span in FASD.

Project description:IntroductionFetal alcohol spectrum disorders (FASD) are the most common cause of non-heritable, preventable mental disability, occurring in almost 5% of births in the United States. FASD lead to physical, behavioral, and cognitive impairments, including deficits related to the cerebellum. There is no known cure for FASD and their mechanisms remain poorly understood. To better understand these mechanisms, we examined the cerebellum on a cellular level by studying microglia, the principal immune cells of the central nervous system, and Purkinje cells, the sole output of the cerebellum. Both cell types have been shown to be affected in models of FASD, with increased cell death, immune activation of microglia, and altered firing in Purkinje cells. While ethanol administered in adulthood can acutely depress the dynamics of the microglial process arbor, it is unknown how developmental ethanol exposure impacts microglia dynamics and their interactions with Purkinje cells in the long term.MethodsTo address this question, we used a mouse model of human 3rd trimester exposure, whereby L7cre/Ai9+/-/Cx3cr1G/+ mice (with fluorescently labeled microglia and Purkinje cells) of both sexes were subcutaneously treated with a binge-level dose of ethanol (5.0 g/kg/day) or saline from postnatal days 4-9. Cranial windows were implanted in adolescent mice above the cerebellum to examine the long-term effects of developmental ethanol exposure on cerebellar microglia and Purkinje cell interactions using in vivo two-photon imaging.ResultsWe found that cerebellar microglia dynamics and morphology were not affected after developmental ethanol exposure. Microglia dynamics were also largely unaltered with respect to how they interact with Purkinje cells, although subtle changes in these interactions were observed in females in the molecular layer of the cerebellum.DiscussionThis work suggests that there are limited in vivo long-term effects of ethanol exposure on microglia morphology, dynamics, and neuronal interactions, so other avenues of research may be important in elucidating the mechanisms of FASD.