CXCL13/CXCR5: a new target for pain treatment.

Pain is a significant global health burden, and current treatments often fail to provide adequate relief due to an incomplete understanding of its mechanisms. This review integrates emerging evidence highlighting the CXCL13/CXCR5 chemokine pathway as a crucial mediator across various pain states, including nociceptive, inflammatory, and neuropathic pain. CXCL13 and CXCR5 are substantially upregulated in pain-related regions such as the spinal cord, dorsal root ganglia (DRG), and cerebrospinal fluid following nerve injury, inflammation, and in conditions like bone cancer or diabetes. The key mechanisms through which they contribute to pain include enhancing neuronal excitability by increasing Nav1.8 sodium channel currents in DRG neurons via p38 MAPK signaling, promoting neuroinflammation by activating NF-κB, ERK, and JNK pathways, which drive the production of pro-inflammatory cytokines (e.g., TNF-α, IL-6, IL-1β) and immune cell infiltration, and activating glial cells, where CXCL13/CXCR5 signaling promotes astrocyte reactivity and indirectly activates microglia, thereby amplifying central sensitization. Genetic knockdown or pharmacological inhibition of CXCL13/CXCR5 has been shown to significantly reduce pain hypersensitivity in preclinical models. The pathway's high tissue specificity in pain pathways and its multifaceted regulation of pain mechanisms make it a promising novel therapeutic target. Future research should address CXCL13/CXCR5 interactions with other pain-related pathways (e.g., CXCL12/CXCR4), explore non-GPCR signaling (e.g., β-arrestins), and validate its potential as a clinical biomarker to guide targeted analgesic development.