Epigenetic mechanisms underlying pathobiology of alcohol use disorder

Recent Advances in the Role of Non-coding RNAs in Fetal Alcohol Spectrum Disorders

Despite numerous preclinical studies modeling fetal alcohol spectrum disorder (FASD)-associated neurodevelopmental deficits to date, a comprehensive molecular landscape dictating these deficits remains poorly understood. Non-coding RNAs constitute a substantial layer of epigenetic regulation of gene expression at the transcriptional, post-transcriptional, translational, and post-translational levels. Yet, little is known about the differential expression of non-coding RNAs in the context of prenatal alcohol exposure (PAE) that are mechanistically linked with FASD-related neurobehavior deficits. This chapter reviews our current knowledge from preclinical studies in non-coding RNA-mediated molecular mechanisms that may underlie FASD pathophysiology. This chapter also summarizes relevant clinical evidence and current efforts in utilizing these non-coding RNA molecules as biomarkers of PAE-associated deficits impacting central nervous system (CNS) function. Unraveling the diverse roles of various species of non-coding RNAs is critical to enhancing our comprehension of these intricate molecular pathways. Understanding these pathways would likely contribute to identifying critical molecular target(s) for developing efficient treatment strategies and prognostic and diagnostic markers fostering advancements in treating and managing FASD-related CNS dysfunction.

Early life adversity: Epigenetic regulation underlying drug addiction susceptibility

Drug addiction is a leading cause of disability worldwide, with more than 70,000 Americans dying from drug overdose in 2019 alone. While only a small percentage of chronic drug users escalate to drug addiction, little is understood on the precise mechanisms of this susceptibility. Early life adversity is causally relevant to adult psychiatric disease and may contribute to the risk of addiction. Here we review recent pre-clinical evidence showing that early life exposure to stress and/or drugs regulates changes in behavior, gene expression, and the epigenome that persist into adulthood. We summarize the major findings and gaps in the preclinical literature, highlighting studies that demonstrate the often profound differences between female and male subjects.

Non-coding RNA in alcohol use disorder by affecting synaptic plasticity

Alcohol use disorder (AUD) is one of the most serious public health problems worldwide. AUD is a complex disorder, and there is ample evidence that genetic predisposition is critical to its development. Recent studies have shown that genetic predisposition leads to the onset of AUD, and alcohol metabolism can affect epigenetic inheritance, which in turn affects synaptic plasticity, alters brain function, and leads to more severe addictive behaviors. Non-coding RNAs (ncRNAs), especially microRNAs (miRNAs) and long non-coding RNAs (lncRNAs), play an important role in alcohol addiction. This paper reviews the regulatory role of ncRNAs. ncRNAs are involved in enzyme and neurotransmitter reaction systems during alcohol use disorder. Alcohol consumption regulates the expression of ncRNAs that mediate epigenetic modification and synaptic plasticity, which play an important role in the development of chronic AUD. ncRNAs may be used not only as predictors of therapeutic responses but also as therapeutic targets of AUD. Chronic alcoholism is more likely to lead to neuroimmune disorders, including permanent brain dysfunction. AUD induced by long-term alcoholism greatly alters the expression of genes in the human genome, especially the expression of ncRNAs. Alcohol can cause a series of pathological changes by interfering with gene expression, such as through disordered miRNA-mRNA expression networks, epigenetic modifications, disordered metabolism, and even synaptic remodeling. ncRNAs are involved in the transition from moderate drinking to alcohol dependence.