Persistent Rheb-induced mTORC1 activation in spinal cord neurons induces hypersensitivity in neuropathic pain

• Published in: Cell death & disease Vol. 11; no. 9; p. 747
• Main Authors: Ma, Xiaqing, Du, Wenjie, Wang, Wenying, Luo, Limin, Huang, Min, Wang, Haiyan, Lin, Raozhou, Li, Zhongping, Shi, Haibo, Yuan, Tifei, Jiang, Wei, Worley, Paul F, Xu, Tao
• Format: Journal Article
• Language: English
• Published: England Springer Nature B.V 12.09.2020; Nature Publishing Group UK
• Subjects: Animals; Brain slice preparation; Cell cycle; Disease Models, Animal; Firing rate; Hypersensitivity; Ion channels (cyclic nucleotide-gated); Localization; Male; Mechanistic Target of Rapamycin Complex 1 - metabolism; Mice; Mice, Inbred C57BL; Mice, Transgenic; Morphine; Neuralgia; Neuralgia - metabolism; Neuralgia - pathology; Neurons - metabolism; Neurons - pathology; Pain; Phenotypes; Phosphorylation; Rapamycin; Ras Homolog Enriched in Brain Protein - metabolism; Signal Transduction; Spinal cord; Spinal Cord - metabolism; Spinal Cord - pathology; TOR protein; TOR Serine-Threonine Kinases - metabolism
• ISSN: 2041-4889; 2041-4889
• DOI: 10.1038/s41419-020-02966-0

The small GTPase Ras homolog enriched in the brain (Rheb) can activate mammalian target of rapamycin (mTOR) and regulate the growth and cell cycle progression. We investigated the role of Rheb-mediated mTORC1 signaling in neuropathic pain. A chronic constriction injury (CCI) model was dopted. CCI induced obvious spinal Rheb expression and phosphorylation of mTOR, S6, and 4-E-BP1. Blocking mTORC1 signal with rapamycin alleviated the neuropathic pain and restored morphine efficacy in CCI model. Immunofluoresence showed a neuronal co-localization of CCI-induced Rheb and pS6. Rheb knockin mouse showed a similar behavioral phenotype as CCI. In spinal slice recording, CCI increased the firing frequency of neurons expressing HCN channels; inhibition of mTORC1 with rapamycin could reverse the increased spinal neuronal activity in neuropathic pain. Spinal Rheb is induced in neuropathic pain, which in turn active the mTORC1 signaling in CCI. Spinal Rheb-mTOR signal plays an important role in regulation of spinal sensitization in neuropathic pain, and targeting mTOR may give a new strategy for pain management.