Summary: Researchers have identified a precise molecular pathway that connects HIV infection to chronic neuropathic pain. Using mammalian models, the study shows how the HIV envelope protein glycoprotein 120 (gp120) drives persistent spinal cord hyper-sensitization, revealing a clear target for focused, non-addictive therapies for chronic pain.
The team demonstrated that gp120 forces overactivation of specific spinal nerve receptors in a defined population of neurons. Mapping this mechanism provides a practical blueprint for reversing virus-driven pain hypersensitivity and designing targeted treatments that spare normal nerve function.
Key Facts
- The scale of HIV-related chronic pain: Chronic neuropathic pain affects a large portion of people living with HIV, and current medications often fail because they do not address the underlying molecular changes caused by the virus.
- The role of gp120: Building on earlier observations that linked the HIV protein gp120 to increased pain sensitivity and, separately, that linked overactive spinal NMDA receptor signaling to neuropathic pain, Hui-Lin Pan’s group tested whether gp120 directly hijacks that receptor pathway.
- Direct spinal impact: In mouse models, microinjection of gp120 into the spinal cord produced an immediate and robust increase in electrical signaling through the implicated receptor complex, demonstrating that the viral protein can reprogram spinal pain processing.
- Cell-type specificity: The receptor amplification driven by gp120 was confined to a distinct, localized population of excitatory dorsal horn neurons rather than producing a diffuse or systemic effect.
- Reversibility with precision tools: Using a combination of pharmacological agents (including gabapentin) and genetic interventions, the investigators disrupted the specific protein interactions underlying the pathway and successfully reversed pain hypersensitivity in the animal models.
- A template for targeted therapies: By pinpointing how gp120 augments α2δ-1–bound NMDA receptors at primary afferent–excitatory neuron synapses, the work suggests a strategy for developing highly specific therapeutics that could treat HIV-associated neuropathic pain and other forms of chronic nerve pain that share the same receptor mechanism.
Source: SfN
Over half of people living with HIV experience chronic pain at some point, and effective treatments have been elusive. In a new Journal of Neuroscience paper, Hui-Lin Pan and colleagues at The University of Texas MD Anderson Cancer Center used mouse models to examine how HIV causes long-lasting pain.
Earlier studies separately associated the viral protein glycoprotein 120 (gp120) with heightened pain sensitivity and overactivity of a class of spinal NMDA receptors with neuropathic pain. Guided by these findings, the investigators explored whether gp120 influences NMDA receptor signaling in spinal circuits responsible for transmitting sensory signals.
Intrathecal delivery of gp120 in mice increased expression and synaptic trafficking of the auxiliary subunit α2δ-1 and the NMDA receptor subunit GluN1 in dorsal root ganglia and the spinal dorsal horn. This effect strengthened α2δ-1–GluN1 interactions and selectively enhanced presynaptic and postsynaptic NMDAR activity at synapses between primary afferents and VGluT2-expressing excitatory dorsal horn neurons, while inhibitory VGAT-expressing neurons were not similarly affected.
Crucially, the gp120-induced enhancement of both presynaptic and postsynaptic NMDAR activity was blocked by gabapentin, an α2δ-1 inhibitory ligand, and by an α2δ-1 C‑terminal peptide designed to disrupt α2δ-1–NMDAR binding. Both pharmacological blockade and genetic interventions targeting Cacna2d1 or GluN1 in primary afferents reduced gp120-driven nociceptive hypersensitivity in the models.
The findings indicate that gp120 elevates nociceptive transmission by amplifying α2δ-1–bound NMDAR activity, effectively increasing the gain on sensory signaling from peripheral afferents to spinal excitatory neurons. Interrupting this molecular interaction therefore represents a promising, precision-oriented therapeutic approach to HIV-associated chronic neuropathic pain.
Pan and colleagues emphasize the translational potential of these results: therapies that prevent pathological protein interactions with the α2δ-1–NMDAR complex could reduce chronic pain without the side effects and addiction risks linked to systemic analgesics.
Key Questions Answered:
A: The study shows that an HIV protein, gp120, alters spinal circuitry at the molecular level. By increasing α2δ-1–bound NMDA receptor activity in specific dorsal horn neurons, gp120 turns normal sensory signals into persistent neuropathic pain. Typical painkillers do not address this structural change, so they often provide limited relief.
A: After mapping the exact pathway by which gp120 amplifies α2δ-1–NMDAR signaling, researchers used targeted pharmacological agents and genetic tools to disrupt that specific interaction. This precision approach reversed hypersensitivity in the animal models while preserving overall neuronal function.
A: Yes. The α2δ-1–bound NMDA receptor mechanism implicated here is also involved in other forms of neuropathic pain. Blocking the pathological protein–receptor interactions identified in this study may therefore provide a broadly applicable therapeutic strategy for diverse chronic pain conditions.
Editorial Notes:
- This article was edited by a Neuroscience News editor.
- The cited journal paper was reviewed in full.
- Additional context was added by the editorial staff.
About this HIV and pain research news
Author: SfN Media
Source: SfN
Contact: SfN Media
Image: Image credit: Neuroscience News
Original Research: Closed access. “HIV-1 gp120 Induces Nociceptive Hypersensitivity via α2δ-1–bound NMDA Receptors at Primary Afferent-Excitatory Neuron Synapses” by Vipasha Gautam, Yuying Huang, Hong Chen, Shao-Rui Chen and Hui-Lin Pan. Journal of Neuroscience. DOI: 10.1523/JNEUROSCI.0368-26.2026
Abstract
HIV-1 gp120 Induces Nociceptive Hypersensitivity via α2δ-1–bound NMDA Receptors at Primary Afferent-Excitatory Neuron Synapses
Sensory neuropathy is a frequent complication of HIV-1 infection, with a majority of affected individuals developing chronic pain. Viral proteins such as gp120 are known contributors to neuronal injury and pain hypersensitivity, but their precise actions on nociceptive signaling were previously unclear. Overactivation of N-methyl-D-aspartate receptors (NMDARs) in the spinal dorsal horn is a recognized feature of neuropathic pain.
This study evaluated how gp120 alters synaptic NMDAR activity in spinal excitatory and inhibitory neurons in male and female mice. Intrathecal gp120 elevated α2δ-1 and GluN1 expression in dorsal root ganglia and the spinal cord, increased α2δ-1–GluN1 interactions, and promoted their synaptic trafficking.
Functionally, gp120 produced hyperactivity of presynaptic NMDARs on primary afferent terminals as well as postsynaptic NMDARs in VGluT2-expressing excitatory dorsal horn neurons, but not in VGAT-expressing inhibitory neurons. The gp120-induced NMDAR hyperactivity was abolished by gabapentin, an α2δ-1 inhibitory ligand, and by an α2δ-1 C‑terminal peptide that disrupts α2δ-1–NMDAR interactions.
Accordingly, treatment with gabapentin or the α2δ-1 C‑terminal peptide reversed gp120-induced persistent nociceptive hypersensitivity. Genetic deletion of Cacna2d1 or selective removal of GluN1 in dorsal root ganglion neurons significantly reduced gp120-induced hypersensitivity.
These results demonstrate that gp120 drives nociceptive hypersensitivity by enhancing presynaptic and postsynaptic activity of α2δ-1–bound NMDARs, thereby amplifying sensory transmission from primary afferents to spinal excitatory neurons. Targeting α2δ-1–associated NMDARs may therefore be a promising, precise therapeutic approach for HIV-associated chronic neuropathic pain.