Astrocyte transcriptional responses to neuronal activity in the olfactory bulb

项目摘要/摘要 星形胶质细胞是广泛分布于大脑和星形胶质细胞-神经元通讯的非神经细胞 在调节行为方面发挥关键作用。感觉刺激，如气味的化学信号，激活神经元 诱导促进感官加工的基因表达变化。虽然这些都在 对于神经元，星形胶质细胞是否也会发生类似的转录变化尚不清楚。在这里，使用体内 神经元激活的化学发生模型，我们表明星形胶质细胞确实经历了强健的基因表达 神经元激活后的变化。通过对这些变化的筛查，确定了一种神经调节剂转运体 嗅球星形胶质细胞表达slc22a3。由于初步研究显示气味诱发的神经元激活也 在嗅球中星形胶质细胞SLc22a3的增加，我们首先询问了slc22a3如何影响嗅球星形胶质细胞的功能。 嗅球？我们发现，星形胶质细胞特异性SLc22a3的过度表达导致了对气味的敏感性增加 提示星形胶质细胞SLC22a3影响星形胶质细胞-神经元之间的通讯。这导致了这样的假设： 星形胶质细胞SLc22a3转录激活在星形胶质细胞-神经元通讯中起重要作用 在嗅觉处理过程中。为了检验这一假设，我们建议使用SLC22a3的功能增益和损失 功能小鼠模型研究星形细胞SLc22a3如何影响小鼠的行为和细胞特性 星形胶质细胞(Aim1)由于Slc22a3运输神经调节剂，如5-羟色胺，我们接下来询问Slc22a3是如何- 5-羟色胺介导的转运影响嗅球星形胶质细胞的分子特性？自最近的研究以来 已经证明5-羟色胺可以直接结合到组蛋白中来激活转录，我们专注于 这种组蛋白5-羟色胺基化的表观遗传修饰。我们发现在嗅球星形胶质细胞中， SLc22a3的过表达控制组蛋白5-羟色基化水平。因此，我们建议从基因上 操纵星形胶质细胞slc22a3的表达以确定slc22a3介导组蛋白5-羟色胺基化的动力学 嗅球(AIM2)。此外，初步数据还显示，组蛋白5-羟色胺基化水平是 气味诱发的神经元激活后，星形胶质细胞的数量增加。因此，使用实验方法 建立在Aims1-2，我将直接研究组蛋白5-羟色胺在星形细胞中的作用。 嗅球(Aim3)。综上所述，这些结果将揭示遗传和表观遗传机制 星形胶质细胞参与嗅觉处理。对于我的职业发展，这些研究将在以下方面提供培训 在我的导师狄宁博士(星形细胞生物学专家)和共同导师阿伦基尔博士的指导下，嗅球生物学 (嗅球电路和行为方面的专家)在贝勒医学院。因为星形胶质细胞密切相关 与神经元有关，在所有神经疾病中都是失调的，这项提议的更广泛的目标是 揭示星形胶质细胞如何促进嗅觉化学感官的健康处理。为了实现这一目标， 拟议中的研究将应用星形胶质细胞生物学的新方法来描绘遗传和表观遗传学。 涉及嗅觉系统正常功能的机制。

Project Summary/Abstract Astrocytes are non-neuronal cells widely distributed in the brain and astrocyte-neuron communication play critical roles in modulation of behavior. Sensory stimuli like chemical signals of odors activate neurons to induce gene expression changes that facilitate sensory processing. While these are well understood in neurons, whether similar transcriptomic changes also occur in astrocytes are unknown. Here, using in vivo chemogenetic models of neuronal activation, we show astrocytes indeed undergo robust gene expression changes after neuronal activation. A screen through these changes identified a neuromodulator transporter Slc22a3 in olfactory bulb astrocytes. Since preliminary studies revealed odor-evoked neuronal activation also increased astrocytic Slc22a3 in the olfactory bulb, we first asked how Slc22a3 affect astrocyte function in the olfactory bulb? We show that overexpression of astrocyte-specific Slc22a3 led to increased sensitivity to odors implying that astrocytic Slc22a3 affects astrocyte-neuron communication. This leads to the hypothesis that transcriptional activation of astrocytic Slc22a3 is essential for mediating astrocyte-neuron communication during olfactory processing. To test this hypothesis, we propose to use Slc22a3 gain-of-function and loss-of- function mouse models to investigate how astrocytic Slc22a3 affect behaviors and cellular properties of astrocytes (Aim1). Since Slc22a3 transports neuromodulators like serotonin, we next asked how Slc22a3- mediated serotonin transport affect molecular properties of olfactory bulb astrocytes? Since recent studies have shown that serotonin can be directly incorporated into histones to activate transcription, we focused on this epigenetic modification of histone serotonoylation. We show that in olfactory bulb astrocytes, overexpression of Slc22a3 controls histone serotonoylation levels. Therefore, we propose to genetically manipulate astrocytic Slc22a3 expression to determine Slc22a3-mediated histone serotonoylation dynamics in the olfactory bulb (Aim2). Furthermore, preliminary data also revealed that histone serotonoylation levels are increased in astrocytes after odor-evoked neuronal activation. Therefore, using experimental approaches established in Aims1-2, I will directly investigate the function of astrocytic histone serotonoylation in the olfactory bulb (Aim3). Taken together, these results will reveal genetic and epigenetic mechanisms of how astrocytes contribute to olfactory processing. For my career development these studies will provide training in olfactory bulb biology under my mentor Dr. Deneen (expert in astrocyte biology) and co-mentor Dr. Arenkiel (expert in olfactory bulb circuits and behaviors) at Baylor College of Medicine. Since astrocytes are intimately connected with neurons and are dysregulated in all neurological disorders, the broader goal of this proposal is to uncover how astrocytes contribute to healthy processing of the chemical senses of smell. Towards this goal, the proposed research will apply new approaches of astrocyte biology to delineate genetic and epigenetic mechanisms involved in normal function of the smell system.