IMT504, a noncoding, non-CpG oligodeoxynucleotide, modulates pain-like behavior in rats undergoing peripheral nerve injury, through mechanisms that remain poorly characterized. Here, we chose the spared nerve injury model in rats to analyze the contribution of mesenchymal stem cells (MSCs) in the mechanisms of action of IMT504. We show that a single subcutaneous administration of IMT504 reverses mechanical and cold allodynia for at least 5 weeks posttreatment. This event correlated with long-lasting increases in the percentage of MSCs in peripheral blood and injured sciatic nerves, in a process seemingly influenced by modifications in the CXCL12-CXCR4 axis. Also, injured nerves presented with reduced tumor necrosis factor-α and interleukin-1β and increased transforming growth factor-β1 and interleukin-10 protein levels. In vitro analysis of IMT504-pretreated rat or human MSCs revealed internalized oligodeoxynucleotide and confirmed its promigratory effects. Moreover, IMT504-pretreatment induced transcript expression of Tgf-β1 and Il-10 in MSCs; the increase in Il-10 becoming more robust after exposure to injured nerves. Ex vivo exposure of injured nerves to IMT504-pretreated MSCs confirmed the proinflammatory to anti-inflammatory switch observed in vivo. Interestingly, the sole exposure of injured nerves to IMT504 also resulted in downregulated Tnf-α and Il-1β transcripts. Altogether, we reveal for the first time a direct association between the antiallodynic actions of IMT504, its promigratory and cytokine secretion modulating effects on MSCs, and further anti-inflammatory actions at injured nerves. The recapitulation of key outcomes in human MSCs supports the translational potential of IMT504 as a novel treatment for neuropathic pain with a unique mechanism of action involving the regulation of neuroimmune interactions.

IMT504 是一种非编码、非 CpG 寡脱氧核苷酸，通过仍知之甚少的机制来调节遭受周围神经损伤的大鼠的疼痛样行为。在这里，我们选择大鼠神经损伤模型来分析间充质干细胞（MSC）在IMT504作用机制中的贡献。我们证明，单次皮下注射 IMT504 可逆转治疗后至少 5 周的机械性和冷异常性疼痛。这一事件与外周血和受损坐骨神经中 MSC 百分比的长期增加相关，这一过程似乎受到 CXCL12-CXCR4 轴修改的影响。此外，受损神经的肿瘤坏死因子-α 和白介素-1β 蛋白水平降低，转化生长因子-β1 和白介素-10 蛋白水平升高。IMT504 预处理的大鼠或人 MSC 的体外分析揭示了内化的寡脱氧核苷酸，并证实了其前移效应。此外，IMT504预处理诱导MSCs中Tgf-β1和IL-10的转录表达；在暴露于受伤的神经后，IL-10的增加变得更加强烈。将受损神经离体暴露于 IMT504 预处理的 MSC 证实了体内观察到的促炎至抗炎转变。有趣的是，受伤神经单独暴露于 IMT504 也会导致Tnf-α和Il-1β转录物下调。总之，我们首次揭示了 IMT504 的抗异常疼痛作用、其对 MSC 的迁移和细胞因子分泌调节作用以及对受损神经的进一步抗炎作用之间的直接关联。人类 MSC 中关键结果的概括支持了 IMT504 作为神经病理性疼痛的新型治疗方法的转化潜力，其独特的作用机制涉及神经免疫相互作用的调节。