Circ_Anks1a通过上调Vegfb介导紫杉醇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. CircRNA exerts its biological function via miRNA sponge in the disease process of nervous system. Our preliminary evidence was shown that expression of circ_Anks1a was significantly upregulated in the rat spinal cord after paclitaxel injected. Intrathecal injection of circ_Anks1a siRNA significantly attenuated the hypersensitivity induced by paclitaxel by inhibiting Vegfb expression. Furthermore, bioinformatics analysis and dual luciferase reporter gene assay system showed that there were binding sites between circ_Anks1a and several miRNA, such as miR-672-5p, which its agomir could inhibit the expression of Vegfb. Also Vegfb siRNA inhibited the enhancement of mEPSC induced by paclitaxel in the dorsal horn of spinal cord. Taken together, circ_Anks1a might regulate the chronic pain process via sponging the Vegfb related miRNA and upregulating Vegfb expression. The presents study is going to discuss that mechanisms of circ_Anks1a upregulates Vegfb expression via the sponge effect on miRNA and the upregulation of Vegfb enhanced the spinal neuron excitability under the process of chronic pain induced by paclitaxel. Our research will provide novel target for chronic pain induced by chemotherapeutic agents.

化疗药引起的慢性疼痛限制其临床应用，机制不清。circRNA能通过吸附miRNA等机制参与神经系统疾病。我们预实验发现：紫杉醇诱导的慢性疼痛显著上调circ_Anks1a，给予circ_Anks1a siRNA抑制Vegfb蛋白上调，缓解慢性疼痛；生物信息学预测和荧光素基因检测发现circ_Anks1a与多个miRNA存在结合位点，其中miR-672-5p的agomir抑制紫杉醇诱导的Vegfb上调。此外，Vegfb siRNA抑制紫杉醇诱导的脊髓背角mEPSC的增强。以上结果提示：circ_Anks1a可能通过吸附Vegfb相关的miRNA上调Vegfb参与慢性疼痛。本项目拟解决⑴circ_Anks1a吸附miRNA介导Vegfb上调的机制；⑵circ_Anks1a介导的Vegfb上调引起脊髓神经元兴奋性增加参与紫杉醇诱导的慢性疼痛的机制。本研究将为化疗药导致的慢性疼痛提供新的治疗靶点。

我们探讨了化疗药紫杉醇引起的外周神经病变的发病机制，我们的研究结果发现，在紫杉醇引起外周神经病变中，大鼠脊髓背的树突棘（dendritic spine）密度增加，形态以不成熟的瘦长型树突棘为主，而在维持阶段，树突棘成熟率增加，密度也增加。slit-robo GTP蛋白激活酶3（srGAP3）的上调增强了dendritic spine在起始阶段数量（Day1-Day10）的增长，但是这个阶段的树突棘形态以不成熟的瘦长型树突棘为主。而在紫杉醇外周神经病变的维持阶段（Day10-Day30），srGAP3的表达量显著下调，srGAP3对Rac1的抑制作用减弱，Rac1的活性作用因此上调，上调的Rac1促进了促进肌动蛋白聚合和树突棘的成熟，从而导致更多的成熟蘑菇形树突棘形成，维持了紫杉醇引起的外周神经病变。在紫杉醇外周神经病变的开始阶段抑制srGAP3，在维持阶段抑制Rac1表达能够更好的减轻紫杉醇引起的外周神经病变。我们的研究结果为准确的治疗紫杉醇引起的外周神经病变提出了更好的解释和作用位点，具有很好的意义。