Selective Glucocorticoid Action in the Developing Brain

通过使用合成糖皮质激素(SGC)进行产前治疗，早产(约占妊娠总数的12%)造成的危及生命、情感和经济的负担已大大减轻。产前sGC可加速组织发育，减少早产儿的呼吸窘迫综合征(RDS)和脑室出血(IVH)，但它们会影响大脑的发育过程，并在以后的生活中引发不利的行为和代谢结果。虽然IVH和RDS的出生后管理在过去40年中有了很大的改善，但sGC给药方案自开始以来一直保持不变。在对产前sGCs的反应中，结局和婴儿死亡率也存在显著的性别差异。我们发现了一条影响胚胎神经干细胞/祖细胞(NSPC)功能的新的sGC途径。具体地说，sGC激活的糖皮质激素受体(GR)的位点特异性磷酸化将其导向特定的基因组靶点，其中一些调控NSPC的增殖。我们假设，在由产前sGC激活的NSPC中，选择基因组(磷酸化GR靶基因)GR通路会影响性别特异性的NSPC功能。所提出的创新和最先进的方法将识别新的分子靶点和途径，负责胎儿大脑中性别和剂量特异性的sGCs效应。目的1利用新生儿脐带血(UCB)的外周血单个核细胞(PBMC)，检测人类产前sGC治疗对GR基因靶点和先前被确定为PBMC生物标志物的部位特异性磷酸化的影响，这些基因靶点和位点特异性磷酸化是神经精神疾病风险增加的成年人的PBMC生物标志。对脐血单个核细胞的体外研究将揭示体内产前sGC暴露是否会对GR反应产生长期影响。目的2通过调控sGC在脑内蓄积的主要外排转运蛋白(MDR-1家族)的调控，确定sGCs在体外和体内对NSPC功能的剂量和性别特异性影响。目的3研究丝氨酸220位GR磷酸化对NSPC功能的影响。目的4确定产前sGC对成年后代情绪和认知行为的影响。从这些研究中，将在独特的GR通路中识别新的生物标记物，这些GR通路与早产儿或足月儿产前sGCs的性别特异性、不良神经发育影响有关。

The life-threatening, emotional and economic burdens of premature birth (~12% of pregnancies) have been greatly alleviated by antenatal treatment with synthetic glucocorticoids (sGCs). Antenatal sGCs accelerate tissue development reducing respiratory distress syndrome (RDS) and intraventricular hemorrhage (IVH) in premature infants, but they can affect developmental processes in the brain and trigger adverse behavioral and metabolic outcomes later in life. While postnatal management of IVH and RDS has greatly improved over the last 40 years, sGC dosing regimens have remained the same since their inception. There are also significant sex differences in outcome and infant mortality in response to antenatal sGCs. We have identified a novel sGC pathway that impacts embryonic neural stem/progenitor cell (NSPC) function. Specifically, sGC-activated site-specific phosphorylation of glucocorticoid receptor (GR) directs it to specific genomic targets, some of which regulate NSPC proliferation. We hypothesize that select genomic (phospho-GR target genes) GR pathways in NSPCs activated by antenatal sGCs impact gender-specific NSPC function. The innovative and state-of-the-art approaches proposed will identify novel molecular targets and pathways responsible for sex- and dose-specific effects of antenatal sGCs in fetal brain. Aim 1 will utilize peripheral blood mononuclear cells (PBMCs) from newborn umbilical cord blood (UCB) to examine the impact of antenatal sGC treatment in humans on GR gene targets and site-specific phosphorylation previously established to be PBMC biomarkers in adults with increased risk for neuropsychiatric disorders. Ex vivo studies with UCB PBMCs will reveal whether antenatal sGC exposure in vivo generates long-term effects on GR response. Aim 2 will identify dose- and sex-specific effects of sGCs on NSPC function in vitro and in vivo through manipulation of the major efflux transporters (Mdr-1 family) that regulate sGC accumulation in the brain. Aim 3 will determine the genomic effects of GR phosphorylation at serine 220 on NSPC function in vitro and in vivo. Aim 4 will determine effects of antenatal sGCs on emotional and cognitive behavior in adult offspring. From these studies, novel biomarkers will be identified in unique GR pathways that are associated with sex-specific, adverse neurodevelopment effects of antenatal sGCs in preterm or full term infants.