Department of Anesthesiology, West China Second University Hospital, Sichuan University, Chengdu, Sichuan, China; Key Laboratory of Birth Defects and Related Diseases of Women and Children, Sichuan University, Ministry of Education, Chengdu, Sichuan, China.
Department of Anesthesiology, West China Second University Hospital, Sichuan University, Chengdu, Sichuan, China; Key Laboratory of Birth Defects and Related Diseases of Women and Children, Sichuan University, Ministry of Education, Chengdu, Sichuan, China.
Cell Signal. 2024 Feb;114:110972. doi: 10.1016/j.cellsig.2023.110972. Epub 2023 Nov 18.
Spinal astrocyte-mediated neuroinflammation is an important mechanism for the maintenance of chronic inflammatory pain. Previous studies have investigated that Ras-related C3 botulinum toxin substrate 1 (Rac1) is closely related to astrocyte activation after central nervous system injury. However, the role of Rac1 in astrocyte activation in chronic inflammatory pain has not been reported.
Complete Freund's adjuvant (CFA)-induced chronic inflammatory pain model and LPS-stimulated astrocytes were used to investigate the role of Rac1 in astrocyte activation and the underlying mechanism. Rac1-interfering adeno-associated virus (AAV) targeting astrocytes was delivered to spinal astrocytes by intrathecal administration and a Rac1 specific inhibitor, NSC23766, was used to block cultured astrocytes. The glial fibrillary acidic protein (GFAP), proinflammatory cytokines, p-NF-κB, and nod-like receptor thermal protein domain associated protein 3 (NLRP3) inflammasome were detected by RT-qPCR, Western blotting, and immunofluorescence to investigate the activation of astrocytes.
CFA induced spinal astrocyte activation and increased the expression of active Rac1 in spinal astrocytes. Knockdown of astrocyte Rac1 alleviated chronic inflammatory pain and inhibited astrocyte activation. Inhibition of Rac1 activation in cultured astrocytes decreased the expression of GFAP and proinflammatory cytokines. Knockdown of Rac1 inhibited the increase of expression of NLRP3 inflammasome and phosphorylation of NF-κB in the spinal lumbar enlargement after CFA injection. Similarly, the inhibition of Rac1 suppressed the increase of NLRP3 inflammasome and p-NF-κB protein level after LPS stimulation.
Knockdown of astrocyte Rac1 attenuated CFA-induced hyperalgesia and astrocyte activation possibly by blocking the expression of NLRP3 inflammasome and phosphorylation of NF-κB.
脊髓星形胶质细胞介导的神经炎症是维持慢性炎症性疼痛的重要机制。先前的研究表明，Ras 相关 C3 肉毒杆菌毒素底物 1（Rac1）与中枢神经系统损伤后星形胶质细胞的激活密切相关。然而，Rac1 在慢性炎症性疼痛中星形胶质细胞激活中的作用尚未报道。
采用完全弗氏佐剂（CFA）诱导的慢性炎症性疼痛模型和 LPS 刺激的星形胶质细胞，研究 Rac1 在星形胶质细胞激活中的作用及其潜在机制。通过鞘内给药将靶向星形胶质细胞的 Rac1 干扰腺相关病毒（AAV）递送至脊髓星形胶质细胞，并使用 Rac1 特异性抑制剂 NSC23766 阻断培养的星形胶质细胞。通过 RT-qPCR、Western blot 和免疫荧光检测星形胶质细胞的 GFAP、促炎细胞因子、p-NF-κB 和核苷酸结合寡聚结构域样受体热蛋白结构域相关蛋白 3（NLRP3）炎症小体的表达，以研究星形胶质细胞的激活。
CFA 诱导脊髓星形胶质细胞激活并增加脊髓星形胶质细胞中活性 Rac1 的表达。星形胶质细胞 Rac1 的敲低减轻了慢性炎症性疼痛并抑制了星形胶质细胞的激活。在培养的星形胶质细胞中抑制 Rac1 激活可降低 GFAP 和促炎细胞因子的表达。Rac1 的敲低抑制了 CFA 注射后脊髓腰膨大 NLRP3 炎症小体和 NF-κB 磷酸化的增加。同样，抑制 Rac1 抑制了 LPS 刺激后 NLRP3 炎症小体和 p-NF-κB 蛋白水平的增加。
星形胶质细胞 Rac1 的敲低减轻了 CFA 诱导的痛觉过敏和星形胶质细胞激活，可能是通过阻断 NLRP3 炎症小体和 NF-κB 磷酸化的表达。
