CXCL13 drives spinal astrocyte activation and neuropathic pain via CXCR5
Bao-Chun Jiang, … , Ru-Rong Ji, Yong-Jing Gao
Bao-Chun Jiang, … , Ru-Rong Ji, Yong-Jing Gao
Published January 11, 2016
Citation Information: J Clin Invest. 2016;126(2):745-761. https://doi.org/10.1172/JCI81950.
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Research Article Neuroscience

CXCL13 drives spinal astrocyte activation and neuropathic pain via CXCR5

Abstract

Recent studies have implicated chemokines in microglial activation and pathogenesis of neuropathic pain. C-X-C motif chemokine 13 (CXCL13) is a B lymphocyte chemoattractant that activates CXCR5. Using the spinal nerve ligation (SNL) model of neuropathic pain, we found that CXCL13 was persistently upregulated in spinal cord neurons after SNL, resulting in spinal astrocyte activation via CXCR5 in mice. shRNA-mediated inhibition of CXCL13 in the spinal cord persistently attenuated SNL-induced neuropathic pain. Interestingly, CXCL13 expression was suppressed by miR-186-5p, a microRNA that colocalized with CXCL13 and was downregulated after SNL. Spinal overexpression of miR-186-5p decreased CXCL13 expression, alleviating neuropathic pain. Furthermore, SNL induced CXCR5 expression in spinal astrocytes, and neuropathic pain was abrogated in Cxcr5–/– mice. CXCR5 expression induced by SNL was required for the SNL-induced activation of spinal astrocytes and microglia. Intrathecal injection of CXCL13 was sufficient to induce pain hypersensitivity and astrocyte activation via CXCR5 and ERK. Finally, intrathecal injection of CXCL13-activated astrocytes induced mechanical allodynia in naive mice. Collectively, our findings reveal a neuronal/astrocytic interaction in the spinal cord by which neuronally produced CXCL13 activates astrocytes via CXCR5 to facilitate neuropathic pain. Thus, miR-186-5p and CXCL13/CXCR5-mediated astrocyte signaling may be suitable therapeutic targets for neuropathic pain.

Authors

Bao-Chun Jiang, De-Li Cao, Xin Zhang, Zhi-Jun Zhang, Li-Na He, Chun-Hua Li, Wen-Wen Zhang, Xiao-Bo Wu, Temugin Berta, Ru-Rong Ji, Yong-Jing Gao

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Figure 5

Cxcr5 is essential for SNL-induced neuropathic pain.

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Cxcr5 is essential for SNL-induced neuropathic pain. (A–D) Acute pain t...
(A–D) Acute pain thresholds and motor function are normal in Cxcr5 KO mice. Thermal sensitivity, measured by (A) tail immersion and (B) Hargreaves test, was comparable in WT and KO mice. Mechanical sensitivity assessed by von Frey test was indistinguishable in WT and KO mice (C). Motor function assessed by recording the falling latency in a Rotarod test was comparable in WT and KO mice (D). n = 11 mice/group (A–C); n = 6 mice/group (D). (E and F) SNL-induced mechanical allodynia (E) and heat hyperalgesia (F) were largely reduced in Cxcr5 KO mice (n = 10) compared with WT mice (n = 8). ***P < 0.001, 2-way repeated measures ANOVA followed by Bonferroni’s test. (G and H) Intraspinal infusion of LV-Cxcr5 shRNA lentivirus in the spinal cord 10 days after SNL alleviated SNL-induced mechanical allodynia (G) and blocked heat hyperalgesia (H). *P < 0.05; **P < 0.01; ***P < 0.001, 2-way repeated measures ANOVA followed by Bonferroni’s test. n = 6 mice/group.