Dopaminergic-Like Neurons Derived from Oral Mucosa Stem Cells by Developmental Cues Improve Symptoms in the Hemi-Parkinsonian Rat Model

Achieving safe and readily accessible sources for cell replacement therapy in Parkinson’s disease (PD) is still a challenging unresolved issue. Recently, a primitive neural crest stem cell population (hOMSC) was isolated from the adult human oral mucosa and characterized in vitro and in vivo. In this study we assessed hOMSC ability to differentiate into dopamine-secreting cells with a neuronal-dopaminergic phenotype in vitro in response to dopaminergic developmental cues and tested their therapeutic potential in the hemi-Parkinsonian rat model. We found that hOMSC express constitutively a repertoire of neuronal and dopaminergic markers and pivotal transcription factors. Soluble developmental factors induced a reproducible neuronal-like morphology in the majority of hOMSC, downregulated stem cells markers, upregulated the expression of the neuronal and dopaminergic markers that resulted in dopamine release capabilities. Transplantation of these dopaminergic-induced hOMSC into the striatum of hemi-Parkinsonian rats improved their behavioral deficits as determined by amphetamine-induced rotational behavior, motor asymmetry and motor coordination tests. Human TH expressing cells and increased levels of dopamine in the transplanted hemispheres were observed 10 weeks after transplantation. These results demonstrate for the first time that soluble factors involved in the development of DA neurons, induced a DA phenotype in hOMSC in vitro that significantly improved the motor function of hemiparkinsonian rats. Based on their neural-related origin, their niche accessibility by minimal-invasive procedures and their propensity for DA differentiation, hOMSC emerge as an attractive tool for autologous cell replacement therapy in PD.

为帕金森病（Parkinson’s Disease, PD）的细胞替代疗法开发安全且易于获取的细胞来源，仍是一项尚未攻克的挑战性难题。近期，研究者从成人口腔黏膜中分离出一类原始神经嵴干细胞群（hOMSC），并完成了其体外与体内的特性鉴定。本研究评估了hOMSC在多巴胺能发育信号诱导下，体外向具备神经元-多巴胺能表型的多巴胺分泌细胞分化的能力，并在半帕金森病大鼠模型中检测了其治疗潜力。研究发现，hOMSC可组成性表达一系列神经元及多巴胺能标志物与关键转录因子。可溶性发育因子可在多数hOMSC中诱导出可重复的神经元样形态，下调干细胞标志物的表达，并上调神经元及多巴胺能标志物的表达，进而使其获得多巴胺释放能力。将这些经多巴胺能诱导的hOMSC移植至半帕金森病大鼠的纹状体后，可改善其行为缺陷，该效果通过苯丙胺诱导旋转行为、运动不对称性及运动协调能力测试得以验证。移植后10周，可在移植侧脑区观察到表达酪氨酸羟化酶（Tyrosine Hydroxylase, TH）的人类细胞，以及多巴胺水平升高的现象。上述结果首次证实，参与多巴胺能神经元（Dopamine Neurons, DA）发育的可溶性因子可在体外诱导hOMSC产生多巴胺能表型，从而显著改善半帕金森病大鼠的运动功能。鉴于hOMSC的神经相关起源、可通过微创操作获取其所处的干细胞龛，以及其向多巴胺能细胞分化的潜能，hOMSC成为帕金森病自体细胞替代疗法的极具吸引力的候选工具。