Oxidative stress induced by NOX2 contributes to neuropathic pain via plasma membrane translocation of PKCε in rat dorsal root ganglion neurons

Abstract

Background Nicotinamide adenine dinucleotide phosphate oxidase 2 (NOX2)-induced oxidative stress, including the production of reactive oxygen species (ROS) and hydrogen peroxide, plays a pivotal role in neuropathic pain. Although the activation and plasma membrane translocation of protein kinase C (PKC) isoforms in dorsal root ganglion (DRG) neurons have been implicated in multiple pain models, the interactions between NOX2-induced oxidative stress and PKC remain unknown. Methods A spared nerve injury (SNI) model was established in adult male rats. Pharmacologic intervention and AAV-shRNA were applied locally to DRGs. Pain behavior was evaluated by Von Frey tests. Western blotting and immunohistochemistry were performed to examine the underlying mechanisms. The excitability of DRG neurons was recorded by whole-cell patch clamping. Results SNI induced persistent NOX2 upregulation in DRGs for up to 2 weeks and increased the excitability of DRG neurons, and these effects were suppressed by local application of gp91-tat (a NOX2-blocking peptide) or NOX2-shRNA to DRGs. Of note, the SNI-induced upregulated expression of PKCε but not PKC was decreased by gp91-tat in DRGs. Mechanical allodynia and DRG excitability were increased by ψεRACK (a PKCε activator) and reduced by εV1-2 (a PKCε-specific inhibitor). Importantly, εV1-2 failed to inhibit SNI-induced NOX2 upregulation. Moreover, the SNI-induced increase in PKCε protein expression in both the plasma membrane and cytosol in DRGs was attenuated by gp91-tat pretreatment, and the enhanced translocation of PKCε was recapitulated by H2O2 administration. SNI-induced upregulation of PKCε was blunted by phenyl-N-tert-butylnitrone (PBN, an ROS scavenger) and the hydrogen peroxide catalyst catalase. Furthermore, εV1-2 attenuated the mechanical allodynia induced by H2O2 Conclusions NOX2-induced oxidative stress promotes the sensitization of DRGs and persistent pain by increasing the plasma membrane translocation of PKCε.

Transcriptional Alterations of Mouse Trigeminal Ganglion Neurons Following Orofacial Inflammation Revealed by Single-Cell Analysis

“…Additionally, identified DEGs and GO terms were also associated with ATP synthesis, oxidative stress and neuroprotection. Emerging evidence has illustrated that ATP pathway and oxidative stress are critically involved in pain regulation ( De Logu et al, 2020 ; Xu et al, 2021 ; Luo et al, 2022 ). Peripheral nerve injury induced by axotomy and TG extraction during our experiments do not rule out the transcriptional alterations of neuroregeneration and neuroprotection genes in neuron.…”

Leonurine Protects Bone Mesenchymal Stem Cells from Oxidative Stress by Activating Mitophagy through PI3K/Akt/mTOR Pathway

“…For the establishment of the cell model, scientists used H 2 O 2 [ 34 ], lipopolysaccharide(LPS) [ 35 ], and dexamethasone [ 36 ] to establish high oxidative stress. According to our results, H 2 O 2 can apparently increase the intracellular ROS level of BMSCs, and many studies also use H 2 O 2 as a suitable way to mimic the oxidative microenvironment in vitro [ 37 ].…”

NADPH Oxidases in Pain Processing

“…Several studies have demonstrated that Nox2 is involved in neuropathic pain processing. For example, Nox2 expression is induced in the spinal cord and DRGs in different rodent models of peripheral nerve injury [ 29 , 63 , 64 , 65 ] and spinal cord injury [ 66 ]. Nox2 expression in the spinal cord seems to be restricted to microglia and is absent in neurons [ 63 ], while in dorsal root ganglia (DRGs), Nox2 has been detected in macrophages and neurons after injury [ 64 , 65 , 67 ].…”