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）的后果表现为严重的口面部疼痛和多种功能障碍，严重影响患者的生活质量。然而，促进SB的确切机制尚不清楚。我们之前发现了神经元5 -羟色胺2A受体基因（HTR2A） rs6313的变异与SB的风险相关，并从SB患者中建立了人类诱导多能干细胞（iPSC）衍生的神经元。研究表明，睡眠时表达5-羟色胺2A受体（5-HT2AR）的gaba能神经元活性的减弱可能参与了SB的发生机制。我们发现在神经发生的早期，SB ipsc衍生的神经元的兴奋性发生了改变。今年，我们从一名SB患者（SB3）和一名未受影响的对照（C3）中建立了另外两个iPSC系。此外，我们还对SNP神经元在神经发生DIV31-51、52-71、72-91和92-111的功能进行了研究。结果表明，在DIV111培养过程中，SB神经元的动作电位发射频率显著高于对照神经元，动作电位增益显著高于对照神经元，动作电位半持续时间显著缩短。SB神经元电生理特性的改变表明受影响的细胞可能过度活跃。

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.