Premature infants with germinal matrix hemorrhage-intraventricular hemorrhage (GMH-IVH) suffer from neurobehavioral deficits as they enter childhood and adolescence. Yet the underlying mechanisms remain unclear. Impaired development and function of interneurons contribute to neuropsychiatric disorders. Therefore, we hypothesized that the occurrence of IVH would reduce interneuron neurogenesis in the medial ganglionic eminence and diminish the population of parvalbumin+ and somatostatin+ cortical interneurons. Since Sonic Hedgehog promotes the production of cortical interneurons, we also postulated that the activation of Sonic Hedgehog signaling might restore neurogenesis, cortical interneuron population, and neurobehavioral function in premature newborns with IVH. These hypotheses were tested in a preterm rabbit model of IVH and autopsy samples from human preterm infants. We compared premature newborns with and without IVH for intraneuronal progenitors, cortical interneurons, transcription factors regulating neurogenesis, single-cell transcriptome of medial ganglionic eminence, and neurobehavioral functions. We treated premature rabbit kits with adenovirus expressing Sonic Hedgehog (Ad-Shh) or green fluorescence protein gene (Ad-GFP) to determine the effect of Sonic Hedgehog activation on the interneuron production, cortical interneuron population, and neurobehavior. We discovered that IVH reduced the number of Nkx2.1+ and Dlx2+ progenitors in the medial ganglionic eminence of both humans and rabbits by attenuating their proliferation and inducing apoptosis. Moreover, IVH decreased the population of parvalbumin+ and somatostatin+ neurons in the frontal cortex of both preterm infants and kits relative to controls. Sonic hedgehog expression and the downstream transcription factors, including Nkx2.1, Mash1, Lhx6, and Sox 6, were also reduced in kits with IVH. Consistent with these findings, single-cell transcriptomic analyses of medial ganglionic eminence identified a distinct subpopulation of cells exhibiting perturbation in genes regulating neurogenesis, ciliogenesis, mitochondrial function, and MAPK signaling in rabbits with IVH. More importantly, restoration of Sonic Hedgehog level by Ad-Shh treatment ameliorated neurogenesis, cortical interneuron population, and neurobehavioral function in kits with IVH. Additionally, Sonic hedgehog activation alleviated IVH-induced inflammation and several transcriptomic changes in the medial ganglionic eminence. Taken together, IVH reduced intraneuronal production and cortical interneuron population by downregulating Sonic Hedgehog signaling in both preterm rabbits and humans. Notably, activation of Sonic hedgehog signaling restored interneuron neurogenesis, cortical interneurons, and cognitive function in rabbit kits with IVH. These findings highlight disruption in cortical interneurons in IVH and identify a novel therapeutic strategy to restore cortical interneurons and cognitive function in infants with IVH. These studies can accelerate the development of new therapies to enhance the neurodevelopmental outcome of survivors with IVH.

中文翻译：

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SHH 激活可恢复脑室内出血新生儿的中间神经元和认知功能

患有生发基质出血-脑室内出血（GMH-IVH）的早产儿在进入儿童期和青春期时会出现神经行为缺陷。然而潜在的机制仍不清楚。中间神经元的发育和功能受损会导致神经精神疾病。因此，我们假设 IVH 的发生会减少内侧神经节隆起的中间神经元神经发生，并减少小白蛋白 + 和生长抑素 + 皮质中间神经元的数量。由于 Sonic Hedgehog 促进皮质中间神经元的产生，我们还假设 Sonic Hedgehog 信号的激活可能会恢复患有 IVH 的早产新生儿的神经发生、皮质中间神经元数量和神经行为功能。这些假设在早产兔 IVH 模型和人类早产儿尸检样本中进行了测试。我们比较了患有和不患有 IVH 的早产新生儿的神经元内祖细胞、皮质中间神经元、调节神经发生的转录因子、内侧神经节隆起的单细胞转录组和神经行为功能。我们用表达 Sonic Hedgehog (Ad-Shh) 或绿色荧光蛋白基因 (Ad-GFP) 的腺病毒处理早产兔试剂盒，以确定 Sonic Hedgehog 激活对中间神经元产生、皮质中间神经元群体和神经行为的影响。我们发现 IVH 通过减弱增殖和诱导细胞凋亡，减少了人和兔子内侧神经节隆起中 Nkx2.1+ 和 Dlx2+ 祖细胞的数量。此外，与对照组相比，IVH 减少了早产儿和幼崽额叶皮层中小白蛋白 + 和生长抑素 + 神经元的数量。在 IVH 试剂盒中，Sonic Hedgehog 表达和下游转录因子（包括 Nkx2.1、Mash1、Lhx6 和 Sox 6）也有所减少。与这些发现一致的是，对内侧神经节隆起的单细胞转录组分析发现了一个独特的细胞亚群，在患有 IVH 的兔子中表现出调节神经发生、纤毛发生、线粒体功能和 MAPK 信号传导的基因扰动。更重要的是，通过 Ad-Shh 治疗恢复 Sonic Hedgehog 水平可改善 IVH 套件中的神经发生、皮质中间神经元数量和神经行为功能。此外，Sonic刺猬激活减轻了IVH引起的炎症和内侧神经节隆起的一些转录组变化。总的来说，IVH 通过下调早产兔和人类的 Sonic Hedgehog 信号传导来减少神经元内的产生和皮质中间神经元的数量。值得注意的是，Sonic hidehog 信号的激活恢复了患有 IVH 的兔子的中间神经元神经发生、皮质中间神经元和认知功能。这些发现强调了 IVH 中皮质中间神经元的破坏，并确定了一种新的治疗策略来恢复 IVH 婴儿的皮质中间神经元和认知功能。这些研究可以加速新疗法的开发，以增强 IVH 幸存者的神经发育结果。