Di Santo Stefano, Seiler Stefanie, Ducray Angélique D, Meyer Morten, Widmer Hans Rudolf
Cell Transplant. 2017 Apr 13;26(4):679-691. doi: 10.3727/096368916X693707. Epub 2016 Nov 7.
Cell replacement therapy is a promising avenue into the investigation and treatment of Parkinson's disease (PD), and in some cases, significant long-term motor improvements have been demonstrated. The main source of donor tissue is the human fetal ventral mesencephalon (FVM), which consists of a mixed neuronal population, and its heterogeneity likely contributes to the inconsistent outcome observed in clinical trials. Therefore, detailed knowledge about the neuronal subpopulations in the VM seems essential for successful cell transplantation. Interestingly, it has been reported that some tyrosine hydroxylase-positive (TH+) neurons in the VM of adult rats and in cultured midbrain-derived neuroblasts coexpress additional neurotransmitters. Thus, the present study investigated, by means of colocalization analyses, the possible expression of GABA or serotonin in TH+ neurons. For that purpose, both fetal rat and human dissociated, organotypic and neurosphere FVM cultures as well as an animal model of PD were investigated. In dissociated rat FVM cultures, approximately 30% of the TH+ neurons coexpressed serotonin, while no colocalization with GABA was observed. Interestingly, coexpression of TH and serotonin was found to be dependent on the time in culture, the plating density, and the exposure to neurotrophic factors, that is, higher cell densities and treatment with brain-derived neurotrophic factor resulted in a significantly reduced coexpression rate. Notably, even though approximately 30% of the dopaminergic neurons in the donor tissue coexpressed serotonin, no colocalization could be detected in grafts 1 month after intrastriatal transplantation into hemiparkinsonian rats. In conclusion, a significant and susceptible subpopulation of dopaminergic neurons in FVM tissues coexpresses serotonin. This might have potential implications for the future selection and handling of cells prior to transplantation in PD.
细胞替代疗法是研究和治疗帕金森病（PD）的一个有前景的途径，在某些情况下，已证明有显著的长期运动改善。供体组织的主要来源是人类胎儿腹侧中脑（FVM），它由混合的神经元群体组成，其异质性可能导致临床试验中观察到的结果不一致。因此，关于中脑神经元亚群的详细知识似乎对成功的细胞移植至关重要。有趣的是，据报道成年大鼠中脑和培养的中脑来源神经母细胞中的一些酪氨酸羟化酶阳性（TH+）神经元共表达其他神经递质。因此，本研究通过共定位分析，研究了TH+神经元中γ-氨基丁酸（GABA）或5-羟色胺（血清素）的可能表达。为此，研究了胎鼠和人分离的、器官型和神经球FVM培养物以及PD动物模型。在分离的大鼠FVM培养物中，约30%的TH+神经元共表达血清素，而未观察到与GABA的共定位。有趣的是，发现TH和血清素的共表达取决于培养时间、接种密度和神经营养因子的暴露情况，即较高的细胞密度和脑源性神经营养因子处理导致共表达率显著降低。值得注意的是，尽管供体组织中约30%的多巴胺能神经元共表达血清素，但在纹状体内移植到偏侧帕金森病大鼠1个月后的移植物中未检测到共定位。总之，FVM组织中一个显著且易受影响的多巴胺能神经元亚群共表达血清素。这可能对未来PD移植前细胞的选择和处理具有潜在意义。
