Department of Pain Pharmacology, Maj Institute of Pharmacology, Polish Academy of Sciences, Kraków, Poland.
Department of Brain Biochemistry, Maj Institute of Pharmacology, Polish Academy of Sciences, Kraków, Poland.
Front Immunol. 2022 Dec 22;13:1058204. doi: 10.3389/fimmu.2022.1058204. eCollection 2022.
Recent studies have indicated the involvement of chemokine-C-motif ligand 1 (XCL1) in nociceptive transmission; however, the participation of its two receptors, canonical chemokine-C-motif receptor 1 (XCR1) and integrin alpha-9 (ITGA9), recently recognized as a second receptor, has not been clarified to date. The aim was to explore by which of these receptors XCL1 reveals its pronociceptive properties and how the XCL1-XCR1 and XCL1-ITGA9 axes blockade/neutralization influence on pain-related behavior and opioid analgesia in the model of neuropathic pain. In our studies we used Albino Swiss mice which were exposed to the unilateral sciatic nerve chronic constriction injury (CCI) as a neuropathic pain model. Animals received single intrathecal () injection of XCL1, XCL1 neutralizing antibodies, antagonist of XCR1 (vMIP-II) and neutralizing antibodies of ITGA9 (YA4), using lumbar puncture technique. Additionally we performed co-administration of abovementioned neutralizing antibodies and antagonists with single dose of morphine/buprenorphine. To assess pain-related behavior the von Frey and cold plate tests were used. To measure mRNA and protein level the RT-qPCR and Western Blot/Elisa/immunofluorescence techniques were performed, respectively. Statistical analysis was conducted using ANOVA with a Bonferroni correction. Presented studies have shown time-dependent upregulation of the mRNA and/or protein expression of XCL1 in the spinal cord after nerve injury as measured on day 1, 4, 7, 14, and 35. Our immunofluorescence study showed that XCL1 is released by astroglial cells located in the spinal cord, despite the neural localization of its receptors. Our results also provided the first evidence that the blockade/neutralization of both receptors, XCR1 and ITGA9, reversed hypersensitivity after intrathecal XCL1 administration in naive mice; however, neutralization of ITGA9 was more effective. In addition, the results proved that the XCL1 neutralizing antibody and, similarly, the blockade of XCR1 and neutralization of ITGA9 diminished thermal and mechanical hypersensitivity in nerve injury-exposed mice after 7 days. Additionally, neutralization of XCL1 improves morphine analgesia. Moreover, blockade of XCR1 positively influences buprenorphine effectiveness, and neutralization of ITGA9 enhances not only buprenorphine but also morphine analgesia. Therefore, blockade of the XCL1-ITGA9 interaction may serve as an innovative strategy for the polypharmacotherapy of neuropathic pain in combination with opioids.
最近的研究表明趋化因子-C-基序配体 1 (XCL1) 参与伤害性传递；然而，其两个受体，经典趋化因子-C-基序受体 1 (XCR1) 和整合素 alpha-9 (ITGA9)，最近被认为是第二个受体，其参与情况尚未阐明。目的是探讨 XCL1 通过哪种受体表现出致痛特性，以及 XCL1-XCR1 和 XCL1-ITGA9 轴的阻断/中和如何影响神经病理性疼痛模型中的疼痛相关行为和阿片类药物镇痛。在我们的研究中，我们使用了暴露于单侧坐骨神经慢性缩窄损伤 (CCI) 的白化瑞士小鼠作为神经病理性疼痛模型。动物通过腰椎穿刺技术接受单次鞘内注射 XCL1、XCL1 中和抗体、XCR1 拮抗剂 (vMIP-II) 和 ITGA9 中和抗体 (YA4)。此外，我们还将上述中和抗体和拮抗剂与单剂量吗啡/丁丙诺啡一起给药。为了评估疼痛相关行为，使用 von Frey 和冷板测试。为了测量 mRNA 和蛋白质水平，分别进行 RT-qPCR 和 Western Blot/Elisa/免疫荧光技术。使用方差分析（Bonferroni 校正）进行统计分析。目前的研究表明，在神经损伤后第 1、4、7、14 和 35 天，脊髓中 XCL1 的 mRNA 和/或蛋白质表达水平呈时间依赖性上调。我们的免疫荧光研究表明，尽管 XCL1 的受体位于神经中，但 XCL1 是由位于脊髓中的星形胶质细胞释放的。我们的结果还首次提供了证据，即鞘内 XCL1 给药后，阻断/中和两个受体 XCR1 和 ITGA9 可逆转鞘内 XCL1 给药后在未受损小鼠中的过敏反应；然而，中和 ITGA9 更为有效。此外，结果证明 XCL1 中和抗体，以及类似地，XCR1 阻断和 ITGA9 中和，可在神经损伤暴露的小鼠中在第 7 天减轻热和机械过敏反应。此外，中和 XCL1 可改善吗啡镇痛作用。此外，XCR1 阻断可积极影响丁丙诺啡的有效性，而 ITGA9 中和不仅增强丁丙诺啡而且增强吗啡镇痛作用。因此，阻断 XCL1-ITGA9 相互作用可能成为结合阿片类药物治疗神经病理性疼痛的多药治疗的创新策略。
