Loss-of-function of Nav1.8/D1639N linked to human pain can be rescued by lidocaine
Loss-of-function of Nav1.8/D1639N linked to human pain can be rescued by lidocaine
复制标题
DOI：
10.1007/s00424-018-2189-x
复制
发表时间：
2018-08
期刊：
影响因子：
--
通讯作者：
Luisa Kaluza;J. Meents;M. Hampl;Corinna Rösseler;P. Hautvast;Silvia Detro-dassen;R. Hausmann;G. Schmalzing;A. Lampert
中科院分区：
文献类型：
--
作者：
Luisa Kaluza;J. Meents;M. Hampl;Corinna Rösseler;P. Hautvast;Silvia Detro-dassen;R. Hausmann;G. Schmalzing;A. Lampert
电压门控钠通道的突变与人类疼痛感知的改变有关。迄今为止研究的大多数这些突变都表明，通道电生理功能的改变与患者的表型之间存在直接和直观的联系。在这项研究中，我们描述了Nav1.8， D1639N的一种变体，该变体先前在患有慢性疼痛综合征“小纤维神经病变”的患者中被发现。通过异种表达系统和膜片钳分析，我们发现Nav1.8/D1639N在不改变Nav1.8生物物理门控特性的情况下降低了电流密度。因此，D1639N变异导致患有慢性疼痛的患者Nav1.8钠通道功能丧失。利用免疫细胞化学和生化方法，我们发现Nav1.8/D1639N损害了通道到细胞膜的运输。无论是β1或β3亚基的共表达，还是27°C的过夜培养，都不能挽救D1639N变体的电流密度。另一方面，与利多卡因孵育过夜后，Nav1.8/D1639N的电流密度完全恢复，很可能是克服了运输缺陷，而苯妥英没有做到这一点。由于利多卡因可以挽救Nav1.8/D1639N的功能丧失，因此它可能为携带该变体的患者提供未来的治疗选择。这些结果表明，在患有慢性疼痛的患者中发现的D1639N变异，由于细胞表面运输受损而导致通道功能丧失，这种运输缺陷可以通过利多卡因修复。
Mutations in voltage-gated sodium channels are associated with altered pain perception in humans. Most of these mutations studied to date present with a direct and intuitive link between the altered electrophysiological function of the channel and the phenotype of the patient. In this study, we characterize a variant of Nav1.8, D1639N, which has been previously identified in a patient suffering from the chronic pain syndrome “small fiber neuropathy”. Using a heterologous expression system and patch-clamp analysis, we show that Nav1.8/D1639N reduces current density without altering biophysical gating properties of Nav1.8. Therefore, the D1639N variant causes a loss-of-function of the Nav1.8 sodium channel in a patient suffering from chronic pain. Using immunocytochemistry and biochemical approaches, we show that Nav1.8/D1639N impairs trafficking of the channel to the cell membrane. Neither co-expression of β1 or β3 subunit, nor overnight incubation at 27 °C rescued current density of the D1639N variant. On the other hand, overnight incubation with lidocaine fully restored current density of Nav1.8/D1639N most likely by overcoming the trafficking defect, whereas phenytoin failed to do so. Since lidocaine rescues the loss-of-function of Nav1.8/D1639N, it may offer a future therapeutic option for the patient carrying this variant. These results demonstrate that the D1639N variant, identified in a patient suffering from chronic pain, causes loss-of-function of the channel due to impaired cell surface trafficking and that this trafficking defect can be rescued by lidocaine.