High-throughput screening using iPSC-derived GABAergic neurons to elucidate disease-relevant phenotypes in serotonin 2A receptor gene variant-related sleep bruxism

睡眠磨牙症(SB)的后果似乎是严重的口腔面部疼痛和几种功能障碍状况，这严重损害了患者的生活质量。然而，促进某人成长的决定性机制还没有被很好地理解。我们之前在神经元5-羟色胺2A受体基因(HTR2A)中发现了与SB风险相关的rs6313变异，并从具有该基因变异的SB患者中建立了人类诱导多能干细胞(IPSC)来源的神经元。提示睡眠中表达5-羟色胺2A受体(5-HT2AR)的GABA能神经元活动减弱可能参与了SB的发生机制。我们发现SB-IPSC来源的神经元在神经发生的早期阶段兴奋性发生了变化。今年，我们从一名SB患者(SB3)和一名未受影响的对照(C3)受试者身上额外建立了两个IPSC系。此外，我们还对DIV31-51、52-71、72-91和92-111处的SNP神经元进行了功能研究。我们发现，在DIV111的培养过程中，SB神经元表现出明显高于对照神经元的动作电位放电频率、增益和短于对照神经元的动作电位半程。SB神经元电生理特性的改变表明，受影响的细胞可能是过度活跃的。

The consequences of sleep bruxism (SB) appear to be serious orofacial pain and several dysfunction conditions, which seriously compromises the patient’s quality of life. However, the definitive mechanisms that promote SB are not well understood. We previously found a variant in the neuronal serotonin 2A receptor gene (HTR2A), rs6313 associated with the risk of SB and established human induced pluripotent stem cell (iPSC)-derived neurons from SB patients with this genetic variant. It has been suggested that attenuating activity of serotonin 2A receptor (5-HT2AR)-expressing GABAergic neurons during sleep may be involved in the mechanism of SB development. We found altered excitability in SB iPSC-derived neurons in the early stage of neurogenesis. This year we established two additional iPSC lines from a SB patient (SB3) and an unaffected control (C3) subject. In addition, we performed functional investigations of the SNP neurons at DIV31-51, 52-71, 72-91, and 92-111 of neurogenesis. We revealed that SB neurons showed significantly higher action potential firing frequency, higher gain, and shorter action potential half duration than control neurons over the course of DIV111 in culture. The altered electrophysiological properties of SB neurons indicate that affected cells may be hyperactive.