Wong Calvin, Rodriguez-Hernandez Luis David, Lister Kevin C, Gu Ning, Cai Weihua, Hooshmandi Mehdi, Fan Jonathan, Brown Nicole, Nguyen Vivienne, Ribeiro-da-Silva Alfredo, Bonin Robert P, Khoutorsky Arkady
Department of Anesthesia, McGill University, Montreal, QC, H3G 1Y6, Canada.
Department of Pharmaceutical Sciences, Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, ON, M5S 3M2, Canada.
Brain. 2025 Feb 3;148(2):675-686. doi: 10.1093/brain/awae275.
The development and maintenance of chronic pain involve the reorganization of spinal nocioceptive circuits. The mechanistic target of rapamycin complex 2 (mTORC2), a central signalling hub that modulates both actin-dependent structural changes and mechanistic target of rapamycin complex 1 (mTORC1)-dependent mRNA translation, plays key roles in hippocampal synaptic plasticity and memory formation. However, its function in spinal plasticity and chronic pain is poorly understood. Here, we show that pharmacological activation of spinal mTORC2 induces pain hypersensitivity, whereas its inhibition, using downregulation of the mTORC2-defining component Rictor, alleviates both inflammatory and neuropathic pain. Cell type-specific deletion of Rictor showed that the selective inhibition of mTORC2 in a subset of excitatory neurons impairs spinal synaptic potentiation and alleviates inflammation-induced mechanical and thermal hypersensitivity and nerve injury-induced heat hyperalgesia. The ablation of mTORC2 in inhibitory interneurons strongly alleviated nerve injury-induced mechanical hypersensitivity. Our findings reveal the role of mTORC2 in chronic pain and highlight its cell type-specific functions in mediating pain hypersensitivity in response to peripheral inflammation and nerve injury.
慢性疼痛的发生和维持涉及脊髓伤害性感受回路的重组。雷帕霉素复合物2(mTORC2)是一个核心信号枢纽,可调节肌动蛋白依赖性结构变化和雷帕霉素复合物1(mTORC1)依赖性mRNA翻译,在海马突触可塑性和记忆形成中起关键作用。然而,其在脊髓可塑性和慢性疼痛中的功能尚不清楚。在这里,我们表明脊髓mTORC2的药理学激活会诱导疼痛超敏反应,而使用mTORC2定义成分Rictor的下调对其进行抑制,则可减轻炎症性疼痛和神经性疼痛。Rictor的细胞类型特异性缺失表明,在一部分兴奋性神经元中选择性抑制mTORC2会损害脊髓突触增强,并减轻炎症诱导的机械性和热超敏反应以及神经损伤诱导的热痛觉过敏。抑制性中间神经元中mTORC2的缺失可强烈减轻神经损伤诱导的机械性超敏反应。我们的研究结果揭示了mTORC2在慢性疼痛中的作用,并突出了其在介导对周围炎症和神经损伤的疼痛超敏反应中的细胞类型特异性功能。