Ethanol selectively disrupts neuronal microexon regulation and chromatin marks in PC12 cells.

Introduction: Exposure to alcohol (ethanol) is the most common toxic insult during human development and is a teratogenic agent associated with abnormalities ranging from behavioral disorders to fetal alcohol syndrome. Ethanol disrupts gene regulatory programs crucial for neuronal identity, including alternative splicing. A distinctive feature of developing neuronal transcriptomes is the high prevalence of microexon inclusion, which consists of short exonic sequences ranging from 3 to 51 nucleotides. However, the impact of ethanol on microexon inclusion remains poorly understood. Methods: In this study, we investigated whether ethanol exposure disrupts neuron-specific alternative splicing programs during neuronal differentiation. To this end, PC12 cells were exposed to 50 mM ethanol throughout five days of NGF-induced differentiation, alongside undifferentiated control cells, to analyze mRNA and protein expression dynamics of key splicing regulators and neurodevelopmental targets. Results: Our data show that in undifferentiated cells, ethanol exposure resulted in a significant reduction in Discussion: Taken together, these findings suggest that ethanol exposure modulates post-transcriptional and chromatin-based mechanisms during neuronal commitment and differentiation. This selective disruption highlights distinct molecular pathways that may contribute to persistent neurodevelopmental alterations relevant to alcohol use disorder, providing new insights into the teratogenic mechanisms of ethanol on the developing nervous system.