Characterizing molecular profiles across puberty to identify the basis of sex-influenced gene expression from discrete brain cells.

导言：青春期在改变大脑动力方面起着重要作用，对男性和女性都有相同和不同的影响。青春期包括身体剧烈的分子、生理和解剖重组，代表着与大脑高度可塑性相关的基本关键期。这种由荷尔蒙驱动的巨大变化为生物差异奠定了基础，这种差异将贯穿整个生命周期。重要的是，大脑由许多细胞类型和亚细胞类型组成，这些细胞类型和亚细胞类型可能对这些性别特定的荷尔蒙变化做出不同的反应。在青春期期间以区域性和细胞特异性的方式跟踪大脑中的分子变化，将使我们能够深入了解大脑如何对这一关键时期做出反应，并最终了解这些变化可能如何导致行为和生理上的性别差异。主要和具体目标：本研究计划的主要目的是追踪青春期荷尔蒙激增诱导的可塑性增强时期个体脑细胞内的基因表达和DNA构象变化。长期目标是确定这些分子变化如何导致性别特定的突触连接模式，进而影响性别特定的行为。具体地说，我们将在互补的模型上使用最先进的单细胞组学技术，包括啮齿动物和人脑，以及体外模型，以描绘这一关键时期和成年期发生的分子变化。方法：从道格拉斯-贝尔加拿大脑库获取特征良好的尸检脑标本。这些样本将来自14-17岁的健康男性和女性捐赠者，他们没有精神或神经疾病病史。鉴于研究人脑只会提供横截面信息，我们将使用啮齿动物和细胞模型来产生跨时间的数据，从而产生分子变化的轨迹。这将使绘制青春期期间基因表达和DNA构象的细胞、区域和性别特定差异的图谱成为可能。细胞将受到不同水平的男性和女性性激素的影响，并按照从几分钟到几天的时间尺度收集。考虑到离散的细胞类型既有不同的激素受体，也有性别特异性的激素受体，对于所有模型，细胞将在个体水平上进行研究。在我的实验室中经常使用的最先进的方法将被用来同时分析转录和开放的染色质图谱。影响：这项研究将对青春期大脑可塑性增强期间的细胞进行分子表征，使我们能够更好地了解大脑成熟时结构和功能组织发生变化的本质。这些资料将描绘出男性和女性大脑在青春期的变化，并阐明性别影响行为的一些分子基础。

Introduction: Puberty plays an important role in altering brain dynamics, with both shared and distinct effects on males and females. The pubertal period consists of intense molecular, physiological and anatomical reorganization of the body, and represents a fundamental critical period associated with heightened brain plasticity. The vast hormonal-driven changes lay the framework for biological differences that persist throughout the lifespan. Importantly, the brain is comprised of numerous cell types and sub cell types that likely respond differently to these sex-specific hormonal changes. Tracking molecular changes in the brain in a regional, and cell-specific manner across puberty will give us enormous insight into how the brain reorganizes in response to this critical period, and ultimately how these changes may underlie sex differences in behavior and physiology. Main and Specific Objectives: The main aim of this research program is to track gene expression and DNA conformational changes within individual brain cells across the period of heightened plasticity induced by the hormonal surges during puberty. The long-term aim is to identify how these molecular changes result in sex-specific synaptic wiring patterns, in turn, influencing sex-specific behaviors. Specifically, we will use state-of-the-art single-cell omics techniques on complementary models, including rodent and human brains, and in vitro models, to profile the molecular changes that occur across this critical period and into adulthood. Methods: Well-characterized postmortem brain samples will be obtained from the Douglas-Bell Canada Brain Bank. These samples will come from healthy 14-17 year-old male and female donors with no history of psychiatric or neurological disorders. Given that studying human brain will only provide cross-sectional information, we will use rodents and cell models to generate data across time, thus producing trajectories of molecular changes. This will enable mapping cell-, regional- and sex-specific divergences in gene expression and DNA conformation across puberty. Cells will be subjected to various levels of male and female sex hormones, and collected along a time scale ranging from several minutes, to several days. Given that discrete cell types have both different, and sex-specific, availabilities of hormone receptors, for all models, cells will be studied at the individual level. State-of-the-art approaches routinely used in my laboratory will be employed to profile the transcriptomic and open chromatin profiles simultaneously. Impact: This research will molecularly characterize cells during the heightened brain plasticity associated with puberty, allowing us to better understand the nature of changes that occur to the structure and functional organization of the brain as it matures. These profiles will map out how male and female brains change during the pubertal period and elucidate some of the molecular underpinnings of sex-influenced behaviours.