Nerve Injury-Induced γH2AX Reduction in Primary Sensory Neurons Is Involved in Neuropathic Pain Processing

Area of Science:

• Neuroscience
• Molecular Biology
• Pain Research

Background:

• Histone variant H2AX phosphorylation at serine 139 (γH2AX) is a key DNA damage marker involved in DNA damage response and disease.
• The role of γH2AX in the development of neuropathic pain remains largely unexplored.

Purpose of the Study:

• To investigate the involvement of γH2AX and its regulatory pathways in neuropathic pain.
• To explore the potential therapeutic implications of targeting γH2AX signaling in pain management.

Main Methods:

• Utilized spared nerve injury (SNI) model in mice to induce neuropathic pain.
• Administered ATM inhibitor (KU55933) and ATM siRNA to modulate γH2AX levels in vivo and in vitro.
• Investigated the effects of inhibiting protein phosphatase 2A (PP2A) on γH2AX dephosphorylation.
• Assessed pain behaviors including mechanical allodynia and thermal hyperalgesia.
• Analyzed the expression of key signaling molecules like ERK and potassium channels (Kcnq2, Kcnd2).

Main Results:

• γH2AX and H2AX expression decreased in dorsal root ganglion (DRG) following SNI.
• ATM, a promoter of γH2AX, was also down-regulated in DRG after nerve injury.
• Inhibition of ATM led to decreased γH2AX, induced mechanical allodynia and thermal hyperalgesia, and altered expression of potassium channels.
• Inhibition of PP2A partially reversed γH2AX down-regulation and relieved pain behaviors.
• ATM inhibition upregulated ERK phosphorylation and enhanced sensory neuron excitability.

Conclusions:

• Down-regulation of γH2AX in DRG contributes to the development of neuropathic pain.
• ATM signaling pathway plays a crucial role in regulating γH2AX levels and pain perception.
• Modulating γH2AX levels and ATM activity presents a potential therapeutic strategy for neuropathic pain.