Cell Biology and Neuroscience, Rutgers University, Piscataway, NJ, USA.
Child Health Institute of New Jersey &Dept. of Neuroscience and Cell Biology, Rutgers Robert Wood Johnson Medical School, New Brunswick, NJ, USA.
Sci Rep. 2016 Oct 4;6:34341. doi: 10.1038/srep34341.
Genetic variation in nicotinic receptor alpha 5 (CHRNA5) has been associated with increased risk of addiction-associated phenotypes in humans yet little is known the underlying neural basis. Induced pluripotent stem cells (iPSCs) were derived from donors homozygous for either the major (D398) or the minor (N398) allele of the nonsynonymous single nucleotide polymorphism (SNP), rs16969968, in CHRNA5. To understand the impact of these nicotinic receptor variants in humans, we differentiated these iPSCs to dopamine (DA) or glutamatergic neurons and then tested their functional properties and response to nicotine. Results show that N398 variant human DA neurons differentially express genes associated with ligand receptor interaction and synaptic function. While both variants exhibited physiological properties consistent with mature neuronal function, the N398 neuronal population responded more actively with an increased excitatory postsynaptic current response upon the application of nicotine in both DA and glutamatergic neurons. Glutamatergic N398 neurons responded to lower nicotine doses (0.1 μM) with greater frequency and amplitude but they also exhibited rapid desensitization, consistent with previous analyses of N398-associated nicotinic receptor function. This study offers a proof-of-principle for utilizing human neurons to study gene variants contribution to addiction.
烟碱型乙酰胆碱受体α5 （CHRNA5）中的遗传变异与人类成瘾相关表型的风险增加有关，但对其潜在的神经基础知之甚少。诱导多能干细胞（iPSC）来源于 CHRNA5 中非同义单核苷酸多态性（SNP）rs16969968 的主要（D398）或次要（N398）等位基因纯合的供体。为了了解这些烟碱型乙酰胆碱受体变异在人类中的影响，我们将这些 iPSC 分化为多巴胺（DA）或谷氨酸能神经元，然后测试它们的功能特性和对尼古丁的反应。结果表明，N398 变异型人类 DA 神经元差异表达与配体受体相互作用和突触功能相关的基因。虽然两种变异体都表现出与成熟神经元功能一致的生理特性，但 N398 神经元群体在 DA 和谷氨酸能神经元中应用尼古丁时，表现出更活跃的兴奋性突触后电流反应。谷氨酸能 N398 神经元对较低的尼古丁剂量（0.1 μM）的反应频率和幅度更大，但它们也表现出快速脱敏，这与之前对 N398 相关烟碱型乙酰胆碱受体功能的分析一致。这项研究为利用人类神经元研究基因变异对成瘾的贡献提供了一个原理证明。
