Studies of histone serotonylation and its role in transcriptional and neural plasticity

项目摘要 在不同的临床疾病中观察到5-羟色胺(5-HT)动态变化，包括但不限于， 与压力和焦虑相关的症状。有趣的是，最近的调查表明 中缝背核(DRN)5-羟色胺能神经元(两者)囊外5-羟色胺“储备”池的存在 胞质和胞核)，但目前尚不清楚它是否可能在胞核中发挥其他作用。 越来越多的文献表明，5-羟色胺能够与某些细胞质和 通过组织转谷氨酰胺酶2(TGM2)转氨基作用的膜结合蛋白，a 已被建议改变单胺基底物的信号性质的修饰。我们 因此，最初的假设是，大脑中的核蛋白可能同样会被修改以控制不同的 它们的功能的各个方面。我们小组(Farrelly等人，《自然》，2018-重新回顾)的研究表明，5HT 可以与组蛋白(特别是组蛋白H3；H3K4me3Q5ser)形成共价键--这一过程称为 5-羟色胺--这对转录传递和早期神经元发育至关重要。因此，我的 在K99/R00提案期间的计划是进一步探索新的组蛋白5-羟色胺基化可能 在指导大脑在出生后正常转录和细胞可塑性方面发挥关键作用 发育和成年期，可能在与以下相关的病理生理状态中被破坏的过程 5-羟色胺能功能障碍(即慢性应激)。在伊恩·梅兹和李申博士的指导下 纽约西奈山医学院，我将从三个不同的目标来阐述这一假说，使用各种 所有的方法。在K99期间(目标1)，我计划直接检查H3K4me3Q5ser之间的关联 发育中和成年小鼠大脑(神经细胞和胶质细胞)的浓缩和转录(Dys)可塑性。这将是 也使用慢性社会失败压力(+/-抗抑郁药)的模型作为一种机制进行研究 干扰5-羟色胺信号转导，从而进一步确定这种修饰在体内的生物学作用。那我会的 评估(目标2)H3 5-羟色胺通过遗传对成年期神经可塑性的贡献 改变标记水平的操作，随后是广泛的行为和转录表型。在……里面 我在Aim3(R00)的独立研究计划，我将进一步剖析H3Q5ser的不同角色，如 我的初步数据表明，5-羟色胺修饰可以孤立地存在于K4me3中并相互作用 与具有假定结合络合物(例如NuRD)的H3K4me3Q5ser相比是独一无二的。这项建议 承诺建立与组蛋白5-羟色胺基化相关的重要转录可塑性模式 大脑。此外，该奖项提供的额外培训和科学环境将是理想的 准备好启动一个独立的研究计划，在多个层面上进行评估(表观基因组学， 细胞/行为)，关于组蛋白5-羟色胺如何导致正常和异常的可塑性状态。

Project Summary Alterations in serotonin (5HT) dynamics are observed in diverse clinical disorders including, but not limited to, stress and anxiety related syndromes. Interestingly, recent investigations have demonstrated an additional presence of ‘reserve’ pools of extravesicular 5HT in dorsal raphe (DRN) serotonergic neurons (both cytoplasmic and nuclear) however it has remained unclear whether it might play additional roles in the nucleus. A growing literature now demonstrates 5HT’s ability to form covalent bonds with certain cytoplasmic and membrane bound proteins via transamination by the tissue Transglutaminase 2 (TGM2) enzyme, a modification that has been suggested to alter the signaling properties of monoaminylated substrates. We therefore initially hypothesized that nuclear proteins in brain may similarly be modified to control distinct aspects of their function. Work from our group (Farrelly et al., Nature, 2018 – re-review) has shown that 5HT can form covalent bonds with histone proteins (specifically histone H3; H3K4me3Q5ser)–a process known as serotonylation–which is critical for transcriptional permissiveness and early neuronal development. Thus, my plan during this K99/R00 proposal is to further explore the hypothesis that novel histone serotonylation may play critical roles in guiding normal patterns of transcriptional and cellular plasticity in brain during postnatal development and into adulthood, processes that may be disrupted in pathophysiological states associated with serotonergic dysfunction (i.e., chronic stress). Under the mentorship of Drs. Ian Maze and Li Shen at the Icahn School of Medicine at Mount Sinai New York, I will address this hypothesis in three distinct aims using a variety of approaches. During the K99 period (Aim 1) I plan to directly examine associations between H3K4me3Q5ser enrichment and transcriptional (dys)plasticity in developing and adult mouse brain (neurons vs. glia). This will also be investigated using a model of chronic social defeat stress (+/- antidepressants) as a mechanism to perturb serotonin signaling and thus further define a biological role for this modification in vivo. I will then assess (Aim 2) the contributions of H3 serotonylation to adulthood neural plasticity through genetic manipulations that alter levels of the mark, followed by extensive behavioral and transcriptional phenotyping. In my independent research program in Aim3 (R00), I will set out to further dissect distinct roles for H3Q5ser, as my preliminary data indicate that the serotonyl modification can exist in isolation of K4me3 and interacts uniquely in comparison to H3K4me3Q5ser with putative binding complexes (e.g., NuRD). This proposal promises to establish important patterns of transcriptional plasticity associated with histone serotonylation in brain. Moreover, the additional training afforded by this award and the scientific environment will ideally prepare me to launch an independent research program evaluating at multiple levels (epigenomic, cellular/behavioral) as to how histone serotonylation contributes to normal and abnormal states of plasticity.