Intraventricular hemorrhage affects production of cortical interneurons

摘要 患有脑室出血(IVH)的早产儿有很高的神经行为障碍风险，包括 注意力不集中、多动症、严重抑郁障碍和癫痫。这些疾病可以归因于 皮质中间神经元发育和功能缺陷。然而，IVH对产后和产后的影响 皮质中间神经元的成熟尚不清楚，即使神经元间神经发生的窗口重叠。 婴儿发生IVH的时期(妊娠23-28周)。中间神经元产生于内侧。 和尾神经节隆起(MGE和CGE)。MGE可产生小白蛋白+(PV)和生长抑素+ (SST)中间神经元，而CGE产生Calretinin+和NRY+中间神经元。中间神经元的产生 在MGE中受许多转录因子的调控，包括Nkx2.1、Dlx1/2、Lhx6/8和Mash1， 主要由Sonic Hedgehog(Shh)信号通路控制。作为有丝分裂后的中间神经元 从MGE迁移到皮质层，Sox6在它们的规格和成熟到PV+的过程中起着关键作用 和SST+中间神经元。这种中间神经元的产生和成熟将受到IVH的影响，因为它 在MGE/CGE中启动，诱导细胞氧化损伤和死亡。我们在兔身上的初步研究 IVH表现为MGE神经发生减少，皮质上层PV+和SST+中间神经元缺失， 与对照组相比，Shh和Sox6水平下降。改善MGE中的神经发生并恢复 皮质神经元间质缺失，我们的目标是a)恢复Shh&>Nkx2.1&>Sox6信号和b)减少氧化 应激可将细胞损伤和死亡降至最低。由于Nrf2转录因子是打开的主要氧化还原开关 在我们的IVH动物模型中，我们将激活Nrf2来最大限度地减少氧化应激。 因此，我们假设：1)IVH破坏了MGE和CGE的神经元间神经发生和分化 导致早产儿和早产兔大脑皮层神经元间的缺陷，以及II)减轻氧化 应激(刺激Nrf2)或激活中间神经元产生(Lenti-mDlx-Shh)和成熟(Lenti-mDlx-Sox6) 将改善IVH兔的PV和SST缺陷以及神经功能。在目标1中，我们将确定 IVH对MGE(Nkx2.1+)神经元祖细胞凋亡、增殖和密度的影响 Dlx1/2+)和CGE(Dlx2+和Coup-TFII+)，b)成熟中间神经元-PV、SST等的密度 C)MGE和CGE的转录变化。此外，我们还将验证 通过分析患有和不患有IVH的早产儿的尸检材料，对兔子在人类中的数据进行了分析。在Aim#2和 #3，我们将评估减轻氧化应激(Ad-Nrf2-GFP或萝卜硫素)或激活 Shh(Lenti-mDlx-Shh-GFP)和Sox6(Lenti-mDlx-Sox6-GFP)在中间神经元中的特异性产生 前体细胞：a)MGE中前体细胞的密度，b)皮质中PV+和SST+神经元的数量 C)MGE的转录变化，d)IVH兔的神经行为功能。建议进行的研究 将加快开发新的治疗方法，以预防IVH婴儿的神经行为障碍。

Abstract Premature infants with intraventricular hemorrhage (IVH) are at high risk of neurobehavioral disorders, including inattention, hyperactivity, major depressive disorders, and seizures. These disorders can be attributed to the defective development and function of cortical interneurons. However, the effect of IVH on the generation and maturation of cortical interneuron is unknown, even though the window of interneuron neurogenesis overlaps with the period when infants develop IVH (23-28 weeks of gestation). Interneurons are produced in the medial and caudal ganglionic eminence (MGE and CGE). MGE gives rise to parvalbumin+ (PV) and somatostatin+ (SST) interneurons, whereas CGE produces calretinin+ and NRY+ interneurons. The production of interneurons in the MGE is regulated by a number of transcription factors, including Nkx2.1, Dlx1/2, Lhx6/8, and Mash1, which are primarily controlled by Sonic Hedgehog (Shh) signaling pathways. As the post-mitotic interneurons migrate from MGE to the cortical layers, Sox6 plays critical roles in their specification and maturation into PV+ and SST+ interneurons. This production and maturation of interneurons would be affected by IVH, because it initiates in the MGE/CGE and induces oxidative cell injury and death. Our preliminary studies in rabbits with IVH show reduced neurogenesis in the MGE, deficit in PV+ and SST+ interneurons in the upper cortical layers, and a decline in Shh and Sox6 levels relative to controls. To ameliorate neurogenesis in the MGE and restore cortical interneuron deficit, our goal is to a) restore Shh > Nkx2.1 > Sox6 signaling and b) reduce oxidative stress to minimize cell injury and death. Since Nrf2 transcription factor is a master redox switch to turn on several antioxidant pathways, we will activate Nrf2 to minimize oxidative stress in our animal model of IVH. Therefore we hypothesize: i) IVH disrupts interneuron neurogenesis and differentiation in the MGE and CGE resulting in interneuron deficits in the cortical layers of preterm humans & rabbits, and ii) alleviating oxidative stress (Nrf2 stimulation) or activating interneuron production (lenti-mDlx-Shh) and maturation (lenti-mDlx-Sox6) will ameliorate PV and SST deficits and neurological function in rabbits with IVH. In Aim #1, we will determine the effect of IVH on a) apoptosis, proliferation, and density of interneuron progenitors in the MGE (Nkx2.1+, Dlx1/2+) and CGE (Dlx2+ & Coup-TFII+), b) the density of mature interneurons—PV, SST and others--in the upper and lower cortical layers, and c) transcriptional changes in the MGE & CGE. Additionally, we will validate rabbit data in humans by analyzing autopsy materials from preterm infants with and without IVH. In Aim #2 and # 3, we will assess the effect of alleviating oxidative stress (Ad-Nrf2-GFP or sulforaphane) or activating production of Shh (lenti-mDlx-Shh-GFP) and Sox6 (lenti-mDlx-Sox6-GFP) specifically in the interneuron progenitors on a) the density of progenitors in the MGE, b) population of PV+ and SST+ neurons in the cortical layers, c) transcriptional changes in MGE, d) neurobehavioral function in rabbits with IVH. The proposed studies will hasten development of new therapies to prevent neurobehavioral disorders in infants with IVH.