Loss of miR-9-2 Causes Cerebral Hemorrhage and Hydrocephalus by Widespread Disruption of Cell-Type-Specific Neurodevelopmental Gene Networks

MIR-9-2 is a broadly and highly expressed microRNA in the developing brain and is frequently deleted in 5q14.3 Microdeletion Syndrome, a rare but severe neurodevelopmental disorder. Despite this, little attention has been paid to the unique contributions of MIR-9-2 to neurodevelopment and disease. We find that deletion of this microRNA leads to embryonic cerebral hemorrhages and severe hydrocephalus, while disrupting gene networks across a wide range of cell types in the developing brain, thus revealing underappreciated and non-redundant molecular, cellular, and system-wide functions for MIR-9-2 in neurodevelopment. Overall design: Following E2A-Cre germline deletion of miR-9-2 in Mir9-2tm1Mtm transgenic mice, embryonic day (E)12.5 and E16.5 cerebral cortices were harvested from homozygous knock-out and wild-type littermate controls for snRNA-seq processing and analysis.

MIR-9-2是一种在发育大脑中广泛且高表达的微小RNA（microRNA），在5q14.3微缺失综合征——一种罕见但病情严重的神经发育障碍——中常发生缺失。尽管已有上述关联，但学界对MIR-9-2在神经发育与疾病中的独特贡献仍关注不足。本研究发现，该微小RNA的缺失会引发胚胎性脑出血与重度脑积水，同时破坏发育大脑中多种细胞类型的基因调控网络，由此揭示了MIR-9-2在神经发育中此前未被充分认知且不可替代的分子、细胞及系统层面功能。总体实验设计：在Mir9-2tm1Mtm转基因小鼠中，通过E2A-Cre生殖系敲除miR-9-2后，分别在胚胎期（E）12.5和E16.5获取纯合敲除型及其野生型同窝对照小鼠的大脑皮层，用于单细胞核RNA测序（snRNA-seq）的建库与分析。