Project 3: Microglia heterogeneity and function in interneuron development

摘要 神经回路需要精确放置正确数量的中间神经元（IN）。这个微妙的过程是 在神经发育和神经精神疾病中脱轨。小胶质细胞，大脑中的巨噬细胞， 影响大脑发育的许多方面，包括皮层的发生，迁移和成熟 中间神经元（cINs）。在我们提出这一建议的初步研究中，我们发现了不同的分子和 细胞特性的人类小胶质细胞在发育中的前脑，我们发现，特定的分子- 定义的亚型在大脑区域中有差异地分布。此外，我们的研究结果表明，GPR 56 表达定义了人类小胶质细胞的一个子集，并且鼠小胶质细胞Gpr 56的缺失导致了 特定脑区PV+中间神经元数量显著减少。然而， 小胶质细胞转录组和功能异质性，特别是在人脑中，仍然是难以捉摸的。的 拟议的研究将建立人类小胶质细胞的出生后细胞和分子异质性， 尾侧和内侧神经节隆起，在小胶质细胞中特异性聚焦于GPR 56。我们假设 小胶质细胞GPR 56促进中间神经元发育。为了验证这一假设和推论，我们将进行 本研究的目的有三：（1）明确小胶质细胞的形态、分布及其与神经元的相互作用; 在人类GE和Arc（一个独特的迁移性神经元簇）中， 在人类侧脑室附近出生时发现的中间神经元）;（2）表征小胶质细胞 在发育中的hMGE、hCGE和Arc中的转录组异质性;和（3）研究细胞类型- 小胶质细胞GPR 56在中间神经元发育中特异性功能研究 小鼠模型最有意义的是，我们正在使用人脑组织进行研究， 转基因小鼠模型，以利用可以在小鼠中完成的许多操作，但总是 将我们的工作建立在我们试图理解的人类条件之上。这项研究的成功将 为神经发育障碍（如自闭症）的起源开辟了一条新的重要研究路线 和精神分裂症考虑到aGPCR作为药物靶点的地位，这一系列研究具有巨大的意义。 平移势特别地，开始设计改变GPR 56作用的药物是可行的 因为发现了它的晶体结构

Abstract Neural circuits require precise placement of correct numbers of interneurons (INs). This delicate process is derailed in neurodevelopmental and neuropsychiatric disease. Microglia, the brain resident macrophages, influence many aspects of brain development, including genesis, migration and maturation of cortical interneurons (cINs). In our preliminary study leading up to this proposal, we discovered diverse molecular and cellular properties of human microglia in the developing forebrain and we found that specific molecularly- defined subtypes are differentially distributed across brain regions. Furthermore, our results show that GPR56 expression defines a subset of human microglia and that deletion of murine microglial Gpr56 leads to a significant reduction in the numbers of PV+ interneurons in specific brain region. However, the full scope of microglia transcriptomic and functional heterogeneity, especially in the human brain, remains elusive. The proposed research will establish the postnatal cellular and molecular heterogeneity of microglia in the human caudal and medial ganglionic eminence with a specific focus on GPR56 in microglia. We hypothesize that microglial GPR56 promotes interneuron development. To test this and corollary hypotheses, we will carry out the following three aims: (1) Define microglia morphology, distribution, and their interactions with neural progenitors (NPCs) and young neurons in the human GEs and the Arc (a unique cluster of migratory interneurons found at birth in the vicinity of the human lateral ventricles); (2) Characterize microglial transcriptomic heterogeneity in the developing hMGE, hCGE and the Arc; and (3) Investigate the cell-type- specific function of microglial GPR56 in interneuron development using microglia-specific conditional knockout mouse model. Most meaningfully, we are conducting our studies using both human brain tissues and transgenic mouse models, to take advantage of the many manipulations that can be done in mice, but always grounding our work in the human conditions we seek to understand. The success of the proposed research will open a novel and important line of research into the origin of neurodevelopmental disorders, such as autism and schizophrenia. Given the status of aGPCRs as drug targets, this line of research carries tremendous translational potential. In particular, it is feasible to begin designing drugs that modify the action of GPR56 given the discovery of its crystal structure.