Rcor2在小鼠大脑皮层发育中调控中间神经元发生的分子机制

Two major classes of neurons exist in mature cortex: excitatory projection neurons and inhibitory interneurons. Although GABAergic interneurons are a minority population compared to excitatory neurons, they are crucial for the normal neural connectivity to ensure brain functions normally. The imbalanced ratio of excitatory neuron vs. interneuron or dysfunction of interneurons leads to epilepsy, autism, schizophrenia, etc. Neural progenitors located at ganglionic eminences of the ventral telencephalon primarily generate interneurons. Epigenetic regulatory complexes play key roles in the modulation of transcriptional regulation underlying neural progenitor cell proliferation and progeny specification. RCOR2, a co-repressor of LSD1, is mainly expressed in the central nervous system (CNS) and plays a key role in epigenetic regulation of cortical development. RCOR2 directly targets promoter regions of Dlx2, Dlx5, Ascl1 and Shh, and represses their expressions in developing neocortex. Depletion of Rcor2 results in reduced excitatory neuron generation, neocortex thickness and brain size. Since RCOR2 directly represses expression of genes critical for interneuron generation, we will investigate how RCOR2 regulates interneuron differentiation, migration and neural circuits formation. In this proposal, we will generate tissue-specific knockout mouse lines, in which, RCOR2 is absent in interneuron progenitor cells, and utilize a series of in-vivo and in-vitro techniques, including immunohistochemistry, embryonic stem cell culture and differentiation, electrophysiology, single-cell transcriptomics to understand the basic cellular and molecular mechanism of how RCOR2 regulates interneuron generation and maintains cortical normal function.

大脑皮层中成熟神经元主要分为两大种类：兴奋性投射神经元和抑制性中间神经元。兴奋性神经元和中间神经元形成神经环路，协同调控着一系列复杂的脑功能。这两种神经元在大脑中的数量比例一旦失调，或者中间神经元功能异常，会引起癫痫、孤独症、精神分裂症等精神疾病。尽管近些年表观遗传调控被认为是生物体实现转录调控的重要方式之一，但是在大脑皮层发育过程中，对于表观遗传层面调控的研究还不多。我们近期的工作已经揭示了组蛋白去甲基化酶LSD1 Corepressor RCOR2在兴奋性神经元发生中的重要作用和调控信号通路。本项目将结合转基因模式动物和干细胞体外培养和诱导体系, 从小鼠模型到人源细胞，结合遗传学、细胞生物学、分子生物学、神经电生理分析、行为学研究、单细胞测序和基因表达谱分析等一系列方法和技术，多角度系统研究表观遗传因子RCOR2对大脑皮层中中间神经元发生的分子调控机制。

大脑皮层中成熟神经元主要分为两大种类：兴奋性投射神经元和抑制性中间神经元。兴奋性神经元和中间神经元形成神经环路，协同调控着一系列复杂的脑功能。本项目结合转基因模式动物和干细胞体外培养和诱导体系, 从小鼠模型到细胞分化培养，结合遗传学、细胞生物学、分子生物学、神经电生理分析、行为学研究、单细胞测序和基因表达谱分析等一系列方法和技术，多角度系统研究表观遗传因子Rcor2对大脑皮层中来源于Nkx2.1+神经干细胞和来源于Dlx5/6+神经干细胞的中间神经元发生的调控机制。此外，我们还揭示了Nkx2.1+神经干细胞中Cenpj蛋白表达缺失会导致小鼠在成年出现病态肥胖的表型。我们发现在胚胎期Cenpj缺失后，下丘脑Nkx2.1+神经干细胞增殖减少，凋亡增加，进而导致成年弓状核POMC神经元数量减少和NPY神经元电生理功能障碍。此外，Cenpj的缺失也减少了下丘脑中从弓状核到室旁核的神经元投射，以及室旁核神经元中黑素皮质素-4受体（MC4R）的表达减少。总之，本研究揭示了调控神经干细胞在脑发育过程中增殖并分化成为特定类型神经元和实现功能的分子机制。