circ_chr10通过上调趋化因子CXCL12介导抗微管化疗药诱导的慢性疼痛的作用及机制

Mechanism of chronic pain induced by chemotherapeutic agents is not clear totally. We have found that CXCL12 expression via STAT3 activation was very important in chronic pain. Circular RNA (circRNA) exerts its biological function by binding protein and miRNA sponge in the disease process of nervous system. Our preliminary evidence was shown that expression of circ_chr10 was significantly upregulated in the rat spinal cord after anti-microtubule chemotherapeutic agents injected. Intrathecal injection of circ_chr10 shRNA significantly attenuated the hypersensitivity induced by anti-microtubule chemotherapeutic agents by inhibiting the STAT3 activation and CXCL12 expression. Furthermore, bioinformatics analysis showed that there were several binding sites between circ_chr10 and CXCL12 miRNA, such as miR-598, which its mimic could inhibit the expression of CXCL12. Taken together, circ_chr10 might regulate the chronic pain process via activating STAT3 or miRNA sponge function. The presents study is going to discuss the mechanism that circ_chr10 promotes the expression of CXCL12 via STAT3 phosphorylation and the sponge effects of miRNA under the process of chronic pain induced by anti-microtubule chemotherapeutic agents. Our research will provide novel target for chronic pain induced by of anti-microtubule chemotherapeutic agents.

化疗药引起的慢性疼痛限制其临床应用，机制不清，我们已经发现STAT3激活后通过上调CXCL12介导慢性疼痛。circRNA能通过结合蛋白质、吸附miRNA等机制参与神经系统疾病。我们预实验发现：抗微管化疗药引起的慢性疼痛显著上调circ_chr10，给予circ_chr10 shRNA可抑制STAT3激活和CXCL12蛋白上调，缓解了慢性疼痛；同时预测发现circ_chr10与CXCL12的miR-598存在结合位点，而miR-598mimic能抑制CXCL12表达。以上结果提示：circ_chr10可能通过激活STAT3或吸附CXCL12相关的miRNA介导CXCL12的上调参与慢性疼痛。本项目拟解决1）circ_chr10通过何种机制激活STAT3介导CXCL12上调；2）circ_chr10与miRNA相互作用介导CXCL12上调的机制。本研究将为化疗药导致的慢性疼痛提供新的治疗靶点

我们探讨了circRNA和炎性因子在化疗药引起的病理性疼痛中的作用，右美托咪定（DEX）和乌司他丁（UTI）在化疗药物引起的病理性疼痛中的作用和机制，以及树突棘在化疗药引起病理性疼痛中的作用。我们的结果表明鞘内注射DEX或腹腔注射UTI通过上调IL-10和激活DRG的2受体，缓解长春新碱引起的的机械性痛觉过敏。联合使用DEX和UTI，可协同缓解VCR引起的疼痛现象。我们还发现了紫杉醇疼痛模型中，锚定蛋白激酶A-150（AKAP150）显著上调，抑制AKAP150显著上调钙调神经磷酸酶（CN）活性，并缓解紫杉醇引起的病理性疼痛现象。紫杉醇抑制了细胞因子IL-4的表达，鞘内注射IL-4有效缓解紫杉醇诱导的超敏反应和背根神经节（DRG）神经元动作电位的频率。CN酶活性降低，导致活化T细胞核因子2（NFAT2）在细胞核中的表达水平降低。染色质免疫沉淀显示，NFAT2与调节IL-4蛋白表达的IL-4基因启动子结合。鞘内过表达NFAT2可通过增加IL4的表达而减轻紫杉醇诱导的疼痛行为。敲除AKAP150可部分恢复DRG中IL-4的表达。AKAP150介导的CN/NFAT2途径调节IL-4可能是紫杉醇诱导的神经病理性疼痛和/或其他神经精神疾病的重要信号通路。我们发现在紫杉醇诱发的神经病理性疼痛起始阶段(initiation phase)，脊髓背角的树突棘密度增加，而在维持阶段(maintenance phase)，树突棘成熟率增加。slit-robo GTP蛋白激活酶3（srGAP3）的增加促进了树突棘在起始阶段的萌发。在维持期，srGAP3表达下降，抑制Rac1活性作用减弱，增强的Rac1活性促进肌动蛋白聚合和树突棘的成熟，从而持续神经性疼痛。在紫杉醇病理性疼痛起始阶段敲除srGAP3或在维持阶段抑制Rac1可减轻神经病理性疼痛。srGAP3在起始阶段和Rac1在维持阶段的联合干预对神经病理性疼痛显示出更好的镇痛效果。我们证明了srGAP3-Rac1在神经病理性疼痛两个阶段的树突棘可塑性中的作用，并相应地为神经病理性疼痛的不同阶段提供了治疗策略。