目的:神经性疼痛,一种无法满足医疗需求的衰弱状况,可以表征为由离子通道功能障碍引起的伤害性神经元的过度兴奋。电压门控钾通道7型(Kv7),负责维持神经元静息膜电位和兴奋性,位于G蛋白偶联受体(GPCRs)的严格控制下。钙敏感受体(CaSR)是一种调节多种离子通道活性的GPCR,但CaSR能否控制Kv7通道功能至今仍未探索。
方法:在重组细胞模型中进行实验,使用膜片钳电生理学和分子生物学技术,小鼠背根神经节(DRG)神经元和人诱导多能干细胞(hiPSC)衍生的伤害性样神经元。
结果:我们的结果表明CaSR在重组细胞模型中表达,hiPSC衍生的伤害性神经元和小鼠DRG神经元,及其激活通过Kv7.2/7.3通道抑制诱导去极化。CaSR-Kv7.2/7.3通道交联是通过Gi/o蛋白-腺苷酸环化酶-环状AMP-蛋白激酶A信号级联介导的。抑制CaSR功能表明,有可能从发药鸡尾酒诱导的兴奋过度中挽救hiPSC衍生的伤害性样神经元。
结论:这项研究表明,CaSR-Kv7.2/7.3通道交联,通过Gi/o蛋白信号通路,有效调节神经元兴奋性,为神经性疼痛的神经元过度兴奋管理提供了一个可行的药理学靶点。
OBJECTIVE: Neuropathic pain, a debilitating condition with unmet medical needs, can be characterised as hyperexcitability of nociceptive neurons caused by dysfunction of ion channels. Voltage-gated potassium channels type 7 (Kv7), responsible for maintaining neuronal resting membrane potential and thus excitability, reside under tight control of G protein-coupled receptors (GPCRs). Calcium-sensing receptor (CaSR) is a GPCR that regulates the activity of numerous ion channels, but whether CaSR can control Kv7 channel function has been unexplored until now.
METHODS: Experiments were conducted in recombinant cell models, mouse dorsal root ganglia (DRG) neurons and human induced pluripotent stem cell (hiPSC)-derived nociceptive-like neurons using patch-clamp electrophysiology and molecular biology techniques.
RESULTS: Our results demonstrate that CaSR is expressed in recombinant cell models, hiPSC-derived nociceptive-like neurons and mouse DRG neurons, and its activation induced depolarisation via Kv7.2/7.3 channel inhibition. The CaSR-Kv7.2/7.3 channel crosslink was mediated via the Gi/o protein-adenylate cyclase-cyclicAMP-protein kinase A signalling cascade. Suppression of CaSR function demonstrated a potential to rescue hiPSC-derived nociceptive-like neurons from algogenic cocktail-induced hyperexcitability.
CONCLUSIONS: This study demonstrates that the CaSR-Kv7.2/7.3 channel crosslink, via a Gi/o protein signalling pathway, effectively regulates neuronal excitability, providing a feasible pharmacological target for neuronal hyperexcitability management in neuropathic pain.