Sex Differences in Fetal Brain-Placental Immune Programming in Maternal Obesity

项目总结 在美国，三分之一的育龄妇女患有肥胖症。在流行病学研究中，母亲肥胖 与儿童神经发育障碍有关，包括认知缺陷、自闭症谱系 精神障碍、焦虑和抑郁、饮食紊乱和注意力缺陷多动障碍。其中许多 疾病有性别偏见，而异常的大脑免疫激活(小胶质细胞启动，或“训练免疫”)有 与它们的发病机制有关。虽然直接评估活着的人胎儿或 新生儿是不可能的，常驻胎盘巨噬细胞(霍夫鲍尔细胞)和小胶质细胞有共同的起源 胎儿的卵黄囊。“母体肥胖的胎脑-胎盘免疫激活”是临床前R01测试 母体肥胖与胎儿脑小胶质细胞和胎盘炎症启动相关的假说 霍夫鲍尔细胞是导致后代认知缺陷的一种有针对性的机制。的一个关键翻译方面 资助的项目是使用单细胞RNA测序(scRNA-Seq)来确定霍夫鲍尔细胞 代表了母亲肥胖背景下小胶质细胞免疫反应的一种新的生物替代品。2019年， 我们获得资助是为了完成以下具体目标：目标1a：确定母亲肥胖是否为主要因素 胎脑和胎盘驻留巨噬细胞对免疫挑战反应过度。目标1b：评估 应用scRNA-Seq和Flow研究Hofbauer细胞能否作为脑小胶质细胞启动的生物替代物 细胞学。目的2：确定是否靶向消融胎儿常驻组织中的促炎信号 巨噬细胞(包括小胶质细胞和胎盘Hofbauer细胞)挽救大鼠海马区学习障碍 子代，使用新型CX3CR1-CreBT：MyD88f/f转基因小鼠。在所有的实验中都会对两性进行评估， 除Aim 1b中的scRNA-Seq外。我们已经完成了16个男性大脑和胎盘的初步测序 肥胖者和瘦肉者的巨噬细胞样本。我们已经展示了新的基因程序和细胞状态 这在母体肥胖的背景下定义了男性小胶质细胞和霍夫鲍尔细胞。 这项行政补充提案旨在扩大父母目标1b中的scRNA-Seq实验 批准包括女性胎儿小胶质细胞和胎盘巨噬细胞。这将使我们能够测试母体 肥胖导致胎儿小胶质细胞和霍夫鲍尔细胞程序的性别特异性改变，以及霍夫鲍尔是否 在母体肥胖的情况下，细胞亚群可以作为胎儿脑小胶质细胞启动的生物替代物。 确定胎儿性别对小胶质细胞和胎盘巨噬细胞基因程序和细胞状态的影响 对肥胖相关的大脑和胎盘免疫激活如何影响特定性别提供关键见解 神经发育结果。如果Hofbauer细胞可以作为一种更容易获得的细胞类型，提供 关于母亲肥胖的大脑小胶质细胞功能的信息，可能对检测有更广泛的意义 其他母亲接触对胎儿大脑免疫激活的影响。了解胎儿的性别差异 母体肥胖的大脑和胎盘免疫程序对于设计精确的治疗方法至关重要。

PROJECT SUMMARY In the United States, one in three women of reproductive age is obese. In epidemiologic studies, maternal obesity is associated with neurodevelopmental morbidity in children, including cognitive deficits, autism spectrum disorder, anxiety and depression, disordered eating, and attention deficit hyperactivity disorder. Many of these disorders have a sex bias, and aberrant brain immune activation (microglial priming, or “trained immunity”), has been implicated in their pathogenesis. While direct evaluation of microglial function in a living human fetus or neonate is impossible, resident placental macrophages (Hofbauer cells) and microglia have a common origin in the fetal yolk sac. “Fetal Brain-Placental Immune Activation in Maternal Obesity” is a pre-clinical R01 that tests the hypothesis that maternal obesity-associated inflammatory priming of fetal brain microglia and placental Hofbauer cells is a targetable mechanism underlying offspring cognitive deficits. A key translational aspect of the funded project is the use of single-cell RNA sequencing (scRNA-Seq) to determine whether Hofbauer cells represent a novel biologic surrogate for microglial immunoreactivity in the setting of maternal obesity. In 2019, we were funded to complete the following specific aims: Aim 1a: Determine whether maternal obesity primes fetal brain and placental resident macrophages to overrespond to an immune challenge. Aim 1b: Evaluate whether Hofbauer cells can serve as a biologic surrogate for brain microglial priming, using scRNA-Seq and flow cytometry. Aim 2: Determine if targeted ablation of pro-inflammatory signaling in fetal resident tissue macrophages (including microglia and placental Hofbauer cells) rescues hippocampal learning deficits in offspring, using a novel Cx3cr1-CreBT:MyD88f/f transgenic mouse. Both sexes are evaluated in all experiments, except the scRNA-Seq in Aim 1b. We have completed initial sequencing for 16 male brain and placental macrophage samples from obese and lean dams. We have demonstrated novel gene programs and cell states that define male microglia and Hofbauer cells in the context of maternal obesity. This administrative supplement proposal aims to expand the scRNA-Seq experiments in Aim 1b of the parent grant to include female fetal microglia and placental macrophages. This will allow us to test whether maternal obesity induces sex-specific alterations in fetal microglial and Hofbauer cell programs, and whether Hofbauer cell subsets can serve as a biologic surrogate for fetal brain microglial priming in the setting of maternal obesity. Determination of how fetal sex impacts microglial and placental macrophage gene programs and cell states will generate key insights into how obesity-associated brain and placental immune activation influences sex-specific neurodevelopmental outcomes. If Hofbauer cells can serve as a more accessible cell type that provides information about brain microglial function in maternal obesity, there may be broader implications for assaying the impact of other maternal exposures on fetal brain immune activation. Understanding sex differences in fetal brain and placental immune programming in maternal obesity is critical to designing precision therapies.