There is intense interest and effort toward regenerating the brain after severe injury. Stem cell transplantation after insult to the central nervous system has been regarded as the most promising approach for repair; however, engrafting cells alone might not be sufficient for effective regeneration. In this study, we have compared neural progenitors (NPs) from the fetal ventricular zone (VZ), the postnatal subventricular zone, and an immortalized radial glia (RG) cell line engineered to conditionally secrete the trophic factor insulin-like growth factor 1 (IGF-1). Upon differentiation in vitro, the VZ cells were able to generate a greater number of neurons than subventricular zone cells. Furthermore, differentiated VZ cells generated pyramidal neurons . In vitro, doxycycline-driven secretion of IGF-1 strongly promoted neuronal differentiation of cells with hippocampal, interneuron and cortical specificity. Accordingly, VZ and engineered RG-IGF-1-hemagglutinin (HA) cells were selected for subsequent in vivo experiments. To increase cell survival, we delivered the NPs attached to a multifunctional chitosan-based scaffold. The microspheres containing adherent NPs were injected subacutely into the lesion cavity of adult rat brains that had sustained controlled cortical impact injury. At 2 weeks posttransplantation, the exogenously introduced cells showed a reduction in stem cell or progenitor markers and acquired mature neuronal and glial markers. In beam walking tests assessing sensorimotor recovery, transplanted RG cells secreting IGF-1 contributed significantly to functional improvement while native VZ or RG cells did not promote significant recovery. Altogether, these results support the therapeutic potential of chitosan-based multifunctional microsphere scaffolds seeded with genetically modified NPs expressing IGF-1 to promote repair and functional recovery after traumatic brain injuries.

中文翻译：

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植入微球支架上的天然和基因工程神经祖细胞的亚急性移植促进颅脑外伤后的修复和功能恢复。

严重受伤后，人们对恢复大脑充满了浓厚的兴趣和精力。损伤中枢神经系统后干细胞移植被认为是最有希望的修复方法。然而，仅移植细胞可能不足以有效再生。在这项研究中，我们比较了胎儿心室区（VZ），产后脑室下区和永生化radial神经胶质（RG）细胞系的神经祖细胞（NP），这些细胞系被设计为有条件地分泌营养因子胰岛素样生长因子1（ IGF-1）。在体外分化后，VZ细胞比脑室下区细胞能够产生更多的神经元。此外，分化的VZ细胞产生锥体神经元。体外，强力霉素驱动的IGF-1分泌强烈促进海马，中间神经元和皮层特异性细胞的神经元分化。因此，选择VZ和工程RG-IGF-1-血凝素（HA）细胞用于随后的体内实验。为了增加细胞存活率，我们提供了附着在基于壳聚糖的多功能支架上的NP。将含有粘附的NP的微球亚急性注射到成年大鼠大脑皮损腔中，该皮腔持续受到可控的皮质撞击损伤。移植后2周，外源导入的细胞显示干细胞或祖细胞标志物减少，并获得成熟的神经元和神经胶质标志物。在评估感觉运动恢复的步行步测中，移植的分泌IGF-1的RG细胞显着促进了功能改善，而天然VZ或RG细胞却没有促进显着恢复。总之，这些结果支持了以壳聚糖为基础的多功能微球支架的治疗潜力，该支架上植入了表达IGF-1的基因修饰的NP以促进颅脑外伤后的修复和功能恢复。