Characterizing NaV1.7 antisense analgesia through antagonist binding, mRNA expression, and neuraxial distribution

Genome-targeting strategies to address NaV1.7-mediated signaling in nociceptive afferents are of great clinical interest given its high selectivity and persistent analgesic outcomes. In the present work, we analyze concentration-dependent effects of suppressing primary afferent NaV1.7 using the intrathecal delivery of an antisense oligonucleotide (ASO) on pain behaviors and demonstrate that NaV1.7 ASOs are likely to modulate pain traffic by blocking afferent signaling at the dorsal root ganglion (DRG) level. Intrathecal NaV1.7 ASOs induced a concentration-dependent gradient of knockdown in DRGs (lumbar to cervical) of Scn9a mRNA and ATTO488-ProTx-II binding in small DRG neurons, and a suppression of pain behaviors initiated by mechanical compression, inflammation, and the NaV1.7 agonist OD-1. The rostro-caudal reduction in mRNA correlated with ASO distribution, with implications for dose-related analgesic profiles. Marked reduction in DRG NaV1.7 binding was seen after intrathecal delivery of an ASO optimal dose, with high selectivity for small DRG neurons. Changes in sciatic nerve NaV1.7 binding were not detected, indicating a pain traffic modulation likely happening due to a block of afferent signaling at the DRG level.