Alcohol-induced epigenetic reprogramming of PPAR-α affects allopregnanolone biosynthesis

抽象的。酒精使用障碍(AUD)的神经基础仍然知之甚少，部分原因是 缺乏概括人类状况表型的翻译模型。细胞的生物合成 皮质边缘神经元中的GABA能神经类固醇，别孕酮(Allo)，调节应激敏感性和 有很强的抗焦虑作用。在慢性间歇性乙醇(CIE)暴露的啮齿动物模型中， 异种生物合成酶5-α-还原酶I型(5-α-RI)和3-α-羟基类固醇脱氢酶的表达 (3)α-HSD与海马区(髋部)和小脑的Allo水平下调有关。始终如一， 在AUD死后脑中，小脑Allo水平和神经类固醇生成蛋白和酶，如 转位蛋白、5-α-RI和3-α-HSD表达降低与表观遗传异常相关 马克。酒精诱导的表观遗传修饰(例如，DNA高甲基化/低甲基化)对转录和 它们对神经类固醇生成基因表达、神经类固醇水平和焦虑的影响知之甚少。 大脑中通过刺激调节焦虑和酒精奖赏的区域可以上调Allo的生物合成 表观遗传可修饰的核受体--过氧化物酶体增殖物调节受体-α 内源调节剂棕榈酰乙醇胺(PEA)。有趣的是，长期饮酒会降低PPAR- α的表达，而PPAR-α的刺激减少了焦虑和酒精摄入量。分子 这些效应背后的机制尚不清楚。我们的初步和公布的结果表明 酒精诱导的PPAR-α的异常调节可能通过降低Allo含量而影响焦虑。假设： 慢性酒精暴露改变甲基化/去甲基化动力学，下调皮质边缘PPAR-α 表达和别孕酮的生物合成，以及升高的焦虑。在雄性和雌性大鼠中，我们将：(目标1) 检查14天CIE暴露(Etoh)、急性乙醇(24小时、W24小时)和长期(7天、W7天)的影响 退出对PPAR-α表达的表观遗传调控及其对神经类固醇生成的下游影响 酶的表达；(目的2)研究CIE暴露和乙醇急性和长期的影响 停药对Allo脑含量的影响；(AIM 3)研究PEA和非诺贝特对小鼠的药物表观遗传学 CIE暴露和急性长期酒精戒断后的同种异体生物合成和焦虑。这项研究可能 揭示CIE诱导的神经生物学改变，并建议酒精戒断症状的治疗目标。

Abstract. The neural substrates underlying alcohol use disorder (AUD), remain poorly understood in part due to lack of translational models that recapitulate phenotypes from the human condition. Biosynthesis of the GABAergic neurosteroid, allopregnanolone (Allo) in corticolimbic neurons, regulates stress sensitivity and induces a potent anxiolytic action. In a rodent model of chronic intermittent ethanol (CIE) exposure, decreased expression of Allo biosynthetic enzymes, 5α-reductase type I (5α-RI) and 3α-hydroxy-steroid dehydrogenase (3α-HSD) is associated with Allo level downregulation in the hippocampus (HIP) and cerebellum. Consistently, in AUD postmortem brain, cerebellum Allo levels and neurosteroidogenic proteins and enzymes, such as the translocator protein (TSPO), 5α-RI and 3α-HSD expression decreased in association with aberrant epigenetic marks. Alcohol-induced epigenetic modifications (e.g., DNA hyper/hypomethylation) on transcriptomics and their impact on neurosteroidogenic gene expression, neurosteroid levels, and anxiety are poorly understood. Allo biosynthesis can be upregulated in brain areas that modulate anxiety and alcohol reward by stimulating the epigenetically modifiable nuclear receptor, peroxisome proliferator-regulated receptor (PPAR)-α by the endogenous modulator, palmitoylethanolamide (PEA). Intriguingly, chronic alcohol exposure decreases PPAR- α expression, while stimulation of PPAR-α by PEA decreases both anxiety and alcohol intake. The molecular mechanisms underlying these effects remain unclear. Our preliminary and published results suggest that alcohol-induced aberrant regulation of PPAR-α may affect anxiety via decreasing Allo content. Hypothesis: Chronic alcohol exposure alters methylation/demethylation dynamics that downregulate corticolimbic PPAR-α expression and allopregnanolone biosynthesis, and elevated anxiety. In male and female rats, we will: (AIM 1) Examine the effect of 14-day CIE exposure (EtOH), ethanol acute (24h, W24h) and protracted (7 days, W7d) withdrawal on the epigenetic regulation of PPAR-α expression and downstream effects on neurosteroidogenic enzyme expression; (AIM 2) Investigate the effects of CIE exposure and ethanol acute and protracted withdrawal on the brain content of Allo; and (AIM 3) Study the pharmacoepigenetics of PEA and fenofibrate on Allo biosynthesis and anxiety after CIE exposure and acute and protracted ethanol withdrawal. This study may unveil CIE-induced neurobiological alterations and suggest treatment targets for alcohol withdrawal symptoms.