移植的人纹状体GABA能神经细胞修复的神经环路在脑损伤模型动物行为学和学习记忆能力恢复中的作用及因果关系的数据

围产期缺氧缺血性脑病是新生儿死亡和永久性神经系统缺陷的主要原因，而基底神经节是在缺氧缺血性脑病患者的大脑中受到选择性和严重影响的主要核团之一，尤其是在重症病例中。人类胚胎干细胞源神经元已经在不同类型的成年脑疾病中展现出巨大潜力。然而，目前尚不清楚移植的人类胚胎干细胞源神经元是否能够修复患有围产期缺氧缺血性脑病的未成熟脑。

在这项研究中，通过将基因标记的人类胚胎干细胞源纹状核神经前体细胞注入缺氧缺血性脑病受损小鼠的同侧纹状核，我们发现移植的细胞逐渐形态学和电生理学上成熟为GABA脊索投射神经元，并显著挽救了缺氧缺血性脑病受损脑区的损失。有趣的是，通过使用免疫组织化学染色结合增强抗坏血酸过氧化物酶基础的免疫电子显微镜和狂犬病病毒介导的跨突触示踪，我们展示了移植物开始向内源目标区域（外侧球状体、内侧球状体、黑质）延伸轴突投射，与宿主纹状核、球状体和黑质神经元形成突触，早在移植后2个月就开始接收广泛而稳定的突触输入。
重要的是，我们进一步证明，在缺氧缺血性脑病受损的大脑中，移植的纹状核脊索投射神经元而不是脊髓GABA神经元在3-6个月的移植后恢复了运动缺陷，这些缺陷可以通过抑制移植物功能来逆转。
这些发现表明，在围产期缺氧缺血性脑病受损的未成熟大脑中，通过纹状核脊索投射神经元可以解剖和功能上重建包括多个回路的基底神经节神经回路，这为围产期缺氧缺血性脑病的细胞替代治疗策略提供了可能性。

Perinatal hypoxic-ischemic encephalopathy (HIE) is a leading cause of neonatal death and permanent neurological deficits. The basal ganglia are among the main nuclei selectively and severely affected in the brains of HIE patients, particularly in severe cases. Human embryonic stem cell-derived neurons have shown great potential in treating various types of adult brain diseases. However, whether transplanted human embryonic stem cell-derived neurons can repair the immature brain damaged by perinatal HIE remains unclear.

In this study, we injected genetically labeled human embryonic stem cell-derived striatal neural progenitor cells into the ipsilateral striatum of mice with hypoxic-ischemic encephalopathy injury. We found that the transplanted cells gradually matured morphologically and electrophysiologically into GABAergic projection neurons, and significantly rescued the tissue loss in the brain regions damaged by HIE. Interestingly, using immunohistochemical staining combined with enhanced ascorbate peroxidase-based immunoelectron microscopy and rabies virus-mediated trans-synaptic tracing, we demonstrated that the grafts began to extend axonal projections to endogenous target regions (lateral globus pallidus, medial globus pallidus, substantia nigra), formed synapses with host striatal, pallidal and nigral neurons, and started to receive widespread and stable synaptic inputs as early as 2 months after transplantation.

Importantly, we further verified that in the HIE-damaged brain, transplanted striatal GABAergic projection neurons, rather than spinal GABAergic neurons, recovered motor deficits at 3 to 6 months after transplantation, and these deficits could be reversed by inhibiting graft function.

These findings indicate that in the immature brain damaged by perinatal HIE, the basal ganglia neural circuits encompassing multiple loops can be anatomically and functionally reconstructed via striatal GABAergic projection neurons, which provides a feasible cell replacement therapeutic strategy for perinatal HIE.