# Lipid Peroxidation Products 4-ONE and 4-HNE Modulate Voltage-Gated Sodium Channels in Neuronal Cell Lines and DRG Action Potentials

## TL;DR

This study shows how lipid peroxidation products 4-HNE and 4-ONE increase neuron excitability and pain sensitivity by altering sodium channel behavior.

## Contribution

The study reveals a novel mechanism by which oxidative stress products modulate sodium channels to enhance pain signaling in sensory neurons.

## Key findings

- 4-HNE and 4-ONE caused a negative shift in sodium channel activation voltage in ND7/23 cells.
- Treatment with LPPs reduced the current threshold for action potentials in dorsal root ganglion neurons.
- LPPs increase sensory neuron excitability and amplify pain signals through sodium channel modulation.

## Abstract

Oxidative stress-induced lipid peroxidation products (LPPs), particularly 4-hydroxy-nonenal (4-HNE) and 4-oxo-nonenal (4-ONE), have recently gained attention for their direct regulation of ion channels essential for pain signaling. In this study, we investigated how these two LPPs affect the electrophysiological properties of neurons, specifically voltage-gated sodium (NaV) channels, thereby influencing sensory neuron excitability and pain pathways. Using human neuroblastoma (SH-SY5Y) and ND7/23 cells (a fusion cell line exhibiting partial sensory neuron properties), we measured changes in NaV channel-mediated sodium currents following treatment with 4-HNE or 4-ONE. Whole-cell patch-clamp experiments showed that 4-ONE (10 µM) and 4-HNE (100 µM) did not significantly alter the peak sodium current amplitude in SH-SY5Y cells. However, in ND7/23 cells, both 4-HNE and 4-ONE induced a negative shift in NaV channel activation voltage dependence, enabling sodium channel activation at lower membrane potentials. Furthermore, current-clamp recordings in primary mouse dorsal root ganglion neurons demonstrated that treatment with 4-ONE and 4-HNE reduced the current threshold required to elicit action potentials and significantly increased action potential firing frequency. These findings indicate that LPPs enhance pain sensitivity by modulating NaV channels, which play a crucial role in pain transmission. In conclusion, 4-HNE and 4-ONE shift the voltage-dependent activation of sodium channels toward more negative potentials, thereby increasing the excitability of primary sensory neurons and amplifying pain signals. This study provides molecular insights into how oxidative stress-related lipid peroxidation contributes to sensory mechanisms and offers potential avenues for developing new treatments for oxidative stress- or inflammation-associated pain.