利用SAM抑制去甲基化对可卡因成瘾的治疗机制研究

Drug abuse can induce DNA methylation change which makes gene abnormal expression. While DNA methylation was controlled by those enzymes that are related to methylation transfer, demethylation or hydroxymethylation such as Dnmt3a, MBD2, Tet1 and et al. It was reported that cocaine addiction makes majority of genes, especially memory related genes, demethlated. So, in this project we want to know the how the addiction drugs change 5mC and 5hmC in the genome and then make the expression changed, how 5mCs transfer to 5hmC because of the addiction drugs and what’s the target genes that banded to Dnmt3a, MBD2 or Tet1 when demethlation happened. And moreover, we treat mouse with SAM before cocaine injection every time to inhibit the demethylase genes or directly de novo methylate the genes as a result inhibiting demethylation. Finally, we will check how SAM work to inhibit demethylation and what effect on drug abuse.

成瘾药物作用于犒赏相关脑区可诱导DNA甲基化改变致使表达异常。而DNA甲基化的改变是受Dnmt3a、MBD2和Tet1等相关甲基化转移酶或其他相关甲基化酶调控，由以往的报道发现可卡因成瘾使大多数基因尤其是记忆相关基因发生去甲基化。本项目拟从DNA甲基化的角度了解成瘾药物在全基因组水平对5mC甲基化组和5hmC羟基甲基化组的改变及对转录组影响、5mC去甲基化为5hmC机制、鉴定Dnmt3a、MBD2和Tet1的和记忆有关的靶基因。另外，通过给可卡因成瘾小鼠补给甲基供体SAM抑制去甲基化，从行为和分子水平评估SAM对药物成瘾治疗的优劣性。为从甲基化的角度治疗药物成瘾提供分子依据和借鉴。

摘要：.可卡因成瘾在分子水平引起基因的改变，其中可卡因成瘾引起的DNA甲基化的改变，但其机理还不清楚。本项目旨在研究当体内DNA甲基化人为改变时对可卡因成瘾的影响以此了解DNA甲基化在可卡因成瘾发生过程中的作用。我们首先比较了SAM（在体内为DNA甲基化提供甲基供体）、SAM前身Methionine及SAH对可卡因成瘾的抑制作用，研究发现Methionine可显著性的抑制可卡因成瘾行为最好。因此我们对NAc区进行了mRNA、microRNA及甲基化测序，测序结果显示甲基化差异位点具有广泛性，分布于各个注释元件。多个基因的启动子区的CpG的甲基化发生改变，其中包括神经相关的多个基因。而转录组测序和miRNA测序也发现了methionine抑制的可卡因成瘾的差异共同富集于MARK signaling pathway、axon guidance pathway等神经相关信号通路，以此说明了成瘾行为的发生可能是由于甲基化的改变直接调控了基因的表达或者经由miRNA调控靶基因的表达。本项目从三个方面挖掘药物成瘾及methionine抑制可卡因成瘾的机理。为了解可卡因成瘾的分子理论及可卡因成瘾的DNA甲基化机制提供视角。