Chronic neuropathic pain, pain that persists long after the initial nerve injury has healed, is notoriously difficult to treat. Part of the problem is that the underlying biology is a moving target: the spinal cord rewires itself at the cellular and molecular level in response to persistent pain signals, and by the time a patient seeks treatment, the system is fundamentally different from its original state.
A new study published in Nature Communications by researchers at the University of New South Wales and the University of Texas at Dallas provides the most detailed picture yet of what that rewiring looks like. Led by Lipin Loo and G. Gregory Neely, the team used single-nucleus RNA sequencing and spatial transcriptomics to map the entire spinal cellular landscape of male mice with entrenched neuropathic pain, before and after effective treatment.
A broad, coordinated response
The findings reveal that chronic pain is not a problem confined to a single cell type or signaling pathway. After peripheral nerve injury, the spinal cord undergoes a broad upregulation of synaptic and excitatory pathways across multiple cell populations, not just in the dorsal horn neurons that directly process pain signals, but also in glial cells: microglia, astrocytes, and oligodendrocytes.
This is a fundamentally non-neuron-centric picture of chronic pain. The glial cells, long considered passive support cells, are transcriptionally reprogrammed alongside neurons, suggesting that chronic pain involves a coordinated tissue-level response in which the entire spinal ecosystem shifts toward a pro-excitatory state.
Spatial organization matters
The use of spatial transcriptomics, techniques that preserve the physical location of gene expression within the spinal cord, allowed the team to map where these transcriptional changes occur. The upregulation is not uniform; it is concentrated in the dorsal horn, the region where pain fibers from the body first synapse onto spinal neurons, but also extends into surrounding regions, suggesting that the pain state spreads beyond the classical pain-processing circuits.
Conservation in humans
A critical finding for translational relevance is that the core cell populations and pathways identified in mice are conserved in the human spinal cord. The team validated their results using tissue from organ donors, confirming that the same cell types and excitatory programs are present in humans.
This means that drugs or gene therapies targeting these pathways in mice have a reasonable chance of engaging the same targets in human patients, a non-trivial finding, given that many promising pain targets identified in rodents have failed to translate.
Treatment reverses the signature
The study also included a treatment arm: mice with entrenched pain received an effective analgesic therapy. After treatment, the injury-induced transcriptional programs were broadly dampened, with many genes returning toward baseline expression levels.
This is important for two reasons. First, it demonstrates that the transcriptional signature of chronic pain is reversible, the spinal cord can return to a near-normal state when pain is effectively treated. Second, it provides a molecular readout for evaluating new pain therapies: instead of relying solely on behavioral pain assays (which are subjective and variable in animals), drug developers could use the spinal transcriptional signature as a quantitative biomarker of treatment efficacy.
Why it matters for patients
Neuropathic pain affects 7-10% of the global population and is the most common reason for chronic opioid use. Existing treatments, gabapentinoids, antidepressants, topical agents, are effective in only a minority of patients and often come with significant side effects.
The new study provides a comprehensive molecular target list: the specific genes and pathways that are upregulated in chronic pain, the cell types that express them, and the spatial organization of the response. Each of these genes is a potential drug target; each cell type is a potential delivery target for gene therapy.
The finding that glial cells are major players in the chronic pain state is particularly important, because glial targets have been largely overlooked by pharmaceutical pain programs, which have focused overwhelmingly on neurons.
Limitations and caveats
The study was performed in male mice only. Sex differences in pain processing are well documented, and female mice may show different or additional spinal signatures. The authors note this as a limitation and call for follow-up studies in females.
The effective pain therapy used in the treatment arm is not identified by name in the published abstract and methods, the authors refer to it as an “effective pain therapy.” Independent replication with a clinically approved drug would strengthen the translational case.
The human validation used tissue from organ donors without chronic pain, meaning the human “baseline” was established but the human chronic pain signature itself was not directly observed. The conserved cell populations suggest the pathways are present, but whether they are upregulated in human chronic pain patients remains to be confirmed.
Source
1. Loo, L., Fujikake, K., Winters, B. L., Cunliffe, G., Saad, S., Clark, T., Hamoudi, Z., Manion, J., Caron, L., Davis, O. C., Tavares-Ferreira, D., Shiers, S., Powell, J. E., Price, T. J., & Neely, G. G. (2026). Spinal signatures of entrenched and treated neuropathic pain in male mice. Nature Communications. https://doi.org/10.1038/s41467-026-74144-3