Faculty of Forensic Medicine, Guangdong Province Translational Forensic Medicine Engineering Technology Research Center, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, Guangdong, China.
Guangdong Province Key Laboratory of Brain Function and Disease, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, Guangdong, China.
Brain Pathol. 2022 Nov;32(6):e13080. doi: 10.1111/bpa.13080. Epub 2022 May 25.
Stress-induced neuroepigenetic programming gains growing more and more interest in the studies of the etiology of posttraumatic stress disorder (PTSD). However, seldom attention is focused on DNA demethylation in fear memory generalization, which is the core characteristic of PTSD. Here, we show that ten-eleven translocation protein 3 (TET3), the most abundant DNA demethylation enzyme of the TET family in neurons, senses environmental stress and bridges neuroplasticity with behavioral adaptation during fear generalization. Foot shock strength dependently induces fear generalization and TET3 expression in nucleus accumbens (NAc) in mice. Inhibition of DNA demethylation by infusing demethyltransferase inhibitors or AAV-Tet3-shRNA virus in NAc enhances the fear generalization and anxiety-like behavior. Furthermore, TET3 knockdown impairs the dendritic spine density, PSD length, and thickness of neurons, decreases DNA hydroxymethylation (5hmC), reduces the expression of synaptic plasticity-related genes including Homer1, Cdkn1a, Cdh8, Vamp8, Reln, Bdnf, while surprisingly increases immune-related genes Stat1, B2m, H2-Q7, H2-M2, C3, Cd68 shown by RNA-seq. Notably, knockdown of TET3 in NAc activates microglia and CD39-P2Y12R signaling pathway, and inhibition of CD39 reverses the effects of TET3 knockdown on the fear memory generalization and anxiety. Overexpression of TET3 by Crispr-dSaCas9 virus delivery to activate endogenous Tet3 in NAc increases dendritic spine density of neurons in NAc and reverses fear memory generalization and anxiety-like behavior in mice. These results suggest that TET3 modulates fear generalization and anxiety via regulating synaptic plasticity and CD39 signaling pathway.
应激诱导的神经表观遗传编程在创伤后应激障碍（PTSD）病因学研究中越来越受到关注。然而，人们很少关注恐惧记忆泛化中的 DNA 去甲基化，这是 PTSD 的核心特征。在这里，我们发现 TET 家族中神经元中含量最丰富的 DNA 去甲基化酶 ten-eleven translocation protein 3（TET3）感知环境应激，并在恐惧泛化过程中介导神经可塑性与行为适应。在小鼠的伏隔核（NAc）中，电击强度依赖性地诱导恐惧泛化和 TET3 表达。在 NAc 中注射去甲基转移酶抑制剂或 AAV-Tet3-shRNA 病毒抑制 DNA 去甲基化会增强恐惧泛化和焦虑样行为。此外，TET3 敲低会损害神经元的树突棘密度、PSD 长度和厚度，降低 DNA 羟甲基化（5hmC）水平，降低突触可塑性相关基因包括 Homer1、Cdkn1a、Cdh8、Vamp8、Reln、Bdnf 的表达，同时令人惊讶地增加了免疫相关基因 Stat1、B2m、H2-Q7、H2-M2、C3、Cd68 的表达，这些结果通过 RNA-seq 得到证实。值得注意的是，在 NAc 中敲低 TET3 会激活小胶质细胞和 CD39-P2Y12R 信号通路，而抑制 CD39 会逆转 TET3 敲低对恐惧记忆泛化和焦虑的影响。通过 Crispr-dSaCas9 病毒传递实现 NAc 中 TET3 的过表达，激活内源性 Tet3，增加 NAc 神经元的树突棘密度，并逆转小鼠的恐惧记忆泛化和焦虑样行为。这些结果表明，TET3 通过调节突触可塑性和 CD39 信号通路来调节恐惧泛化和焦虑。
