Development Of High Throughput Electrophysiology Assays Of Recombinant Nav1.9 Channels

The Nav1.9 voltage dependent sodium channel has long been a desirable target for potential pain therapeutics owing to the highly restricted expression in peripheral sensory neurons. More recently human genetic evidence has been produced which directly links Nav1.9 to human pain disorders, increasing the motivation to develop pharmacological screening methodologies. The primary barrier to assay development has been removed with the generation of robust recombinant Nav1.9 cell lines which recapitulate the unique biophysical properties of the channel. We have previously reported the generation and characterization of human, mouse and rat Nav1.9 channels stably expressed in human HEK-293 cells which exhibit the slowly activating and inactivating inward sodium channel currents that are characteristic of native Nav1.9 (Lin et al, 2016). Nanion's SyncroPatch 384PE high throughput electrophysiology (HTEP) system allows for high fidelity assessment and detailed biophysical characterization of NaV channels with up to 384 simultaneous recordings. To accelerate the pharmacological characterization of NaV1.9 we have sought to develop HTEP assays on the Syncropatch platform. Here we report that SyncroPatch recordings of recombinant Nav1.9 channels can recapitulate the pharmacological properties of Nav1.9. Our results show stable recordings of human and rat orthologs of Nav1.9. Recordings in the absence and presence of known Nav1.9 inhibitors (lidocaine, tetracaine, TC-N 1752) were robust and stable, allowing for accurate measurements of compound IC50s. Additionally, biophysical properties of voltage-dependent activation and inactivation properties were characterized. Collectively, these results show that Nav1.9 channels can studied on high throughput electrophysiological systems, facilitating the search for novel pain therapeutics.