Targeting spinal mechanistic target of rapamycin complex 2 alleviates inflammatory and neuropathic pain

Abstract

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.

Keywords: AKT; Rictor; inflammatory pain; mTORC2; neuropathic pain; spinal cord.