Endocannabinoids regulate microglia in developing brain

内源性大麻素调节大脑发育中的小胶质细胞

• 批准号: 10386019
• 负责人: MARGARET M. MCCARTHY
• 金额: $ 49.57万
• 依托单位: UNIVERSITY OF MARYLAND BALTIMORE
• 依托单位国家: 美国
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-04-01 至 2027-02-28
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10386019
• 关键词: 2-arachidonylglycerol; Adolescence; Adolescent; Adult; Age; Amygdaloid structure; Androgen Receptor; Androgens; Astrocytes; Behavior; Birth; Brain; Brain region; Breast Feeding; CNR1 gene; CNR2 gene; Cell Survival; Cells; Chemotactic Factors; Complement; Complement 3b; Complex; Consumption; Dependovirus; Development; Endocannabinoids; Enzymes; Epigenetic Process; Exposure to; Face; Family member; Female; Foundations; Future; Gene Targeting; Genes; Goals; Human; Immune; Immune system; In Situ Hybridization; Innate Immune System; Internet; Knowledge; Left; Legal; Life; Marijuana; Measures; Medial; Mediating; Medical; Membrane Lipids; Messenger RNA; Microglia; Natural Immunity; Neonatal; Neuroimmune system; Neurons; Newborn Infant; Organ; Participant; Perception; Phagocytes; Phagocytosis; Phenotype; Play; Population; Pregnancy; Process; Production; Proliferating; Proteins; RNA; Rattus; Research; Safety; Sex Differences; Signal Transduction; Signaling Molecule; Small Interfering RNA; Small Nuclear RNA; Social Behavior; Source; Specificity; Stimulus; Surface; System; THC exposure; Techniques; Time; Vacuum; androgen sensitive; astrocyte progenitor; axon guidance; brain cell; cell type; complement system; critical period; density; endogenous cannabinoid system; excitatory neuron; fetal; inhibitory neuron; male; marijuana use in pregnancy; neural circuit; neurogenesis; perinatal brain; programs; response; sex; social; tool; transcriptome; transcriptomics

Endocannabinoids (EDCs) and the innate immune system are two early signaling systems which independently and together profoundly influence brain development. Critical windows of development are also often sensitive periods for disruption by exogenous stimuli. We have discovered a unique critical period in the neonatal amygdala of the rat during which the innate immune cells of the brain, microglia, actively engulf and kill newborn cells that if left unmolested would have gone on to become astrocytes. Through this mechanism the future density of astrocytes in the amygdala is determined. Most remarkably, the optimal density is lower for males than females in that it is causally responsible for increased neuronal activity many weeks later during epochs of adolescent social play. Equally remarkable, the increased phagocytic activity of microglia in the male amygdala is a direct consequence of a higher EDC tone, which is in turn developmentally programmed by elevated androgens in neonatal males. Changes to either androgen levels or, more importantly, EDC tone, including by exposure to THC, during the critical period permanently alters the neuronal/astrocytic population and playfulness during adolescence. Marijuana use during pregnancy and breastfeeding is prevalent and increasing due to legalization, decriminalization and medicalization but we are largely ignorant of the potential consequences to the fetal and newborn brain. Advances in transcriptomics and adeno-associated virus (AAV) techniques provide new tools for exploration and precision not previously accessible for the rat. A primary goal is a deep mechanistic understanding of endocannabinoid-induced microglia phagocytosis of astrocytic progenitors to illuminate with unprecedented specificity the interaction between immune, neuronal, astrocytic and progenitor cells. An additional goal is to establish a larger framework for understanding development THC exposure that converges on inhibitory neurons in brain regions regulating sex-typic social behaviors. We will achieve these dual ends via the following Specific Aims. Aim 1 will fully characterize the endocannabinoid and innate immune systems of the developing amygdala by high precision cell phenotyping, identification of the source of complement proteins needed for phagocytosis, and transcriptomics to identify genes mediating cell survival. In Aim 2 we will selectively reduce androgen receptor in one cell type at a time to determine the source of the sex difference in endocannabinoid tone and Aim 3 will interrogate the relationship between the effects of THC, EDCs and androgen action with an emphasis on inhibitory neurons across brain regions. Combined, these studies will provide unprecedented clarity in the cellular participants and mechanisms establishing a sex difference in a social circuit and how that process can go awry as a consequence of developmental THC exposure.

内源性大麻素（EDC）和先天免疫系统是两个早期的信号系统，它们独立并共同影响大脑发育。发育的关键窗口通常也是外在刺激破坏的敏感时期。我们在大鼠的新生儿杏仁核中发现了一个独特的关键时期，在此期间，大脑的先天免疫细胞，小胶质细胞，积极地吞噬并杀死新生细胞，如果剩下的话，那将继续成为星形胶质细胞。通过这种机制，确定了杏仁核中星形胶质细胞的未来密度。最值得注意的是，男性的最佳密度低于女性，因为它在许多星期后在青少年社交活动时期内导致神经元活动增加。同样引人注目的是，雄性杏仁核中小胶质细胞的吞噬活性增加是EDC张力较高的直接结果，而新生儿雄性中雄激素升高则在发育中编程。在关键时期，雄激素水平或更重要的是EDC张力，包括暴露于THC，会永久改变青春期神经/星形胶质细胞的种群和嬉戏性。怀孕和母乳喂养期间的大麻使用很普遍，并且由于合法化，非刑事化和医疗化而增加，但我们在很大程度上不了解对胎儿和新生大脑的潜在后果。转录组学和腺相关病毒（AAV）技术的进展为探索和精度提供了新的工具，以前无法使用大鼠。一个主要目标是对内源性大麻素诱导的星形胶质细胞祖细胞的小胶质细胞吞噬作用有深刻的理解，以毫无前所未有的特异性照明免疫，神经元，星形胶质细胞和祖细胞之间的相互作用。另一个目标是建立一个更大的框架来理解发展，该框架在调节性典型社会行为的大脑区域中会融合抑制性神经元。我们将通过以下特定目标实现这些双端。 AIM 1将通过高精度细胞表型，鉴定吞噬吞噬作用所需的补体蛋白质来鉴定发育中的杏仁核的内源性大麻素和先天免疫系统，以及鉴定介导细胞存活的基因的转录组学。在AIM 2中，我们将一次选择性地减少一种细胞类型的雄激素受体，以确定内源性大麻素张力的性别差异的来源，AIM 3将询问THC，EDCS和雄激素作用的影响，重点介绍整个大脑区域的抑制性神经元。这些研究结合在一起，将在细胞参与者和机制中提供前所未有的清晰度，从而在社会回路中建立性别差异，以及由于发育性THC暴露而导致该过程如何出现。