成纖維細(xì)胞去分化為全能性或多能性細(xì)胞圖,，圖片來自維基共享資源,。
誘導(dǎo)性多功能干細(xì)胞(induced pluripotent stem cell, iPSC)是治療神經(jīng)疾病的一種大有希望的細(xì)胞替換療法,。比如,，人們使用人iPSC和小鼠iPSC產(chǎn)生改善帕金森疾病模式大鼠中癥狀的多巴胺能神經(jīng)元(dopaminergic neuron),。根據(jù)發(fā)表在Journal of Parkinson's Disease期刊上的一篇研究論文,，來自日本的一組科學(xué)家在靈長類模式動物中評價(jià)了人來源iPSC獲得的神經(jīng)祖細(xì)胞(neural progenitor cells, NPCs)的生長、分化和功能,，闡明了它們的治療潛力,。
日本東京大學(xué)Jun Takahashi博士是這篇論文的通訊作者。他說,，“我們開發(fā)出一系列不含飼養(yǎng)細(xì)胞的培養(yǎng)方法誘導(dǎo)人iPSCs變成NPCs,，將處于不同分化階段的NPCs移植到帕金森疾病模式猴子腦部。我們開發(fā)出使用核磁共振成像(magnetic resonance imaging, MRI),、正電子放射斷層造影術(shù)(positron emission tomography, PET),、免疫細(xì)胞化學(xué)技術(shù)和行為分析的方法評價(jià)移植的NPCs的生長和多巴胺能活性，其中所采用的這些技術(shù)在臨床前研究中是非常有用的,。”
MPTP是一種導(dǎo)致帕金森疾病癥狀的神經(jīng)毒素,。研究人員將人iPSCs移植進(jìn)經(jīng)過MPTP處理的實(shí)驗(yàn)室小鼠和猴子的腦部。他們發(fā)現(xiàn)在不含飼養(yǎng)細(xì)胞的培養(yǎng)條件下孵育的iPSCs產(chǎn)生功能性的中腦多巴胺能神經(jīng)元,。Takahashi.博士注意到,，“在以前的研究中，中腦多巴胺能神經(jīng)元是從人iPSCs中誘導(dǎo)產(chǎn)生的,，但是這種方法需要與小鼠基質(zhì)飼養(yǎng)細(xì)胞(stromal mouse feeder cell)或基質(zhì)膠(Matrigel,，譯者注：它目前人胚胎干細(xì)胞的無飼養(yǎng)層培養(yǎng)體系中常規(guī)使用的包被材料)共同孵育。我們的不含飼養(yǎng)細(xì)胞的方法將更適合于臨床應(yīng)用,。”
在體內(nèi)促進(jìn)功能性多巴胺能神經(jīng)元成熟需要用生長因子預(yù)處理,。MRI和PET成像技術(shù)允許對體內(nèi)細(xì)胞增殖和活性進(jìn)行實(shí)時監(jiān)控,。該研究證實(shí)在移植的NPCs中多巴胺合成、運(yùn)輸和重新攝取反映多巴胺能活性,，這種方法也能夠用于人帕金森疾病患者,。
Takahashi博士作出結(jié)論：“我們的結(jié)果有助于在帕金森疾病模式靈長類動物中評價(jià)從人iPSC獲得的神經(jīng)元細(xì)胞的存活、分化和功能,。盡管在臨床應(yīng)用之前我們不得不使用更多的靈長類模式動物進(jìn)行附加的臨床前研究,，我們相信我們的發(fā)現(xiàn)有助于人們開發(fā)出治療帕金森疾病的細(xì)胞替換療法。” (生物谷：towersimper編譯)
doi:10.3233/JPD-2011-11070
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Survival of Human Induced Pluripotent Stem Cell–Derived Midbrain Dopaminergic Neurons in the Brain of a Primate Model of Parkinson's Disease
Tetsuhiro Kikuchi, Asuka Morizane, Daisuke Doi, Hirotaka Onoe, Takuya Hayashi, Toshiyuki Kawasaki, Hidemoto Saiki, Susumu Miyamoto, Jun Takahashi
Before induced pluripotent stem cells (iPSCs) can be used to treat neurologic diseases, human iPSC-derived neural cells must be analyzed in the primate brain. In fact, although mouse and human iPSCs have been used to generate dopaminergic (DA) neurons that are beneficial in rat models of Parkinson's disease (PD), human iPSC-derived neural progenitor cells (NPCs) have not been examined in primate brains. Here, we generated NPCs at different stages of predifferentiation using a feeder-free culture method, and grafted them into the brains of a monkey PD model and NOD-SCID mice. Magnetic resonance imaging (MRI), positron emission tomography (PET), immunocytochemistry, and behavioral analyses revealed that NPCs pretreated with Sonic hedgehog and fibroblast growth factor-8 followed by glial cell–derived neurotrophic factor, brain-derived neurotrophic factor, ascorbic acid, and dibutyryl cyclic AMP resulted in smaller grafts than those without these treatments, and survived as DA neurons in a monkey brain as long as six months. Thus, for the first time, we describe a feeder-free neural differentiation method from human iPSCs and an evaluation system that can be used to assess monkey PD models.
