title: Autophagy activated by tuberin/mTOR/p70S6K suppression is a protective mechanism against local anaesthetics neurotoxicity.
abstract: The local anaesthetics (LAs) are widely used for peripheral nerve blocks, epidural anaesthesia, spinal anaesthesia and pain management. However, exposure to LAs for long duration or at high dosage can provoke potential neuronal damages. Autophagy is an intracellular bulk degradation process for proteins and organelles. However, both the effects of LAs on autophagy in neuronal cells and the effects of autophagy on LAs neurotoxicity are not clear. To answer these questions, both lipid LAs (procaine and tetracaine) and amide LAs (bupivacaine, lidocaine and ropivacaine) were administrated to human neuroblastoma SH-SY5Y cells. Neurotoxicity was evaluated by MTT assay, morphological alterations and median death dosage. Autophagic flux was estimated by autolysosome formation (dual fluorescence LC3 assay), LC3-II generation and p62 protein degradation (immunoblotting). Signalling alterations were examined by immunoblotting analysis. Inhibition of autophagy was achieved by transfection with beclin-1 siRNA. We observed that LAs decreased cell viability in a dose-dependent manner. The neurotoxicity of LAs was tetracaine > bupivacaine > ropivacaine > procaine > lidocaine. LAs increased autophagic flux, as reflected by increases in autolysosome formation and LC3-II generation, and decrease in p62 levels. Moreover, LAs inhibited tuberin/mTOR/p70S6K signalling, a negative regulator of autophagy activation. Most importantly, autophagy inhibition by beclin-1 knockdown exacerbated the LAs-provoked cell damage. Our data suggest that autophagic flux was up-regulated by LAs through inhibition of tuberin/mTOR/p70S6K signalling, and autophagy activation served as a protective mechanism against LAs neurotoxicity. Therefore, autophagy manipulation could be an alternative therapeutic intervention to prevent LAs-induced neuronal damage.
authors.affiliation: Department of Anesthesiology, First Affiliated Hospital with Nanjing Medical University, Nanjing, China.
authors.forename: Jingwei
authors.initials: J
authors.lastname: Xiong
authors.affiliation: Department of Anesthesiology, First Affiliated Hospital with Nanjing Medical University, Nanjing, China.
authors.forename: Qiuyue
authors.initials: Q
authors.lastname: Kong
authors.affiliation: Department of Anesthesiology, First Affiliated Hospital with Nanjing Medical University, Nanjing, China.
authors.forename: Leyang
authors.initials: L
authors.lastname: Dai
authors.affiliation: Department of Anesthesiology, First Affiliated Hospital with Nanjing Medical University, Nanjing, China.
authors.forename: He
authors.initials: H
authors.lastname: Ma
authors.affiliation: Department of Anesthesiology, First Affiliated Hospital with Nanjing Medical University, Nanjing, China.
authors.forename: Xiaofei
authors.initials: X
authors.lastname: Cao
authors.affiliation: Department of Geriatrics, First Affiliated Hospital with Nanjing Medical University, Nanjing, China.
authors.forename: Li
authors.initials: L
authors.lastname: Liu
authors.affiliation: Department of Anesthesiology, First Affiliated Hospital with Nanjing Medical University, Nanjing, China.
authors.forename: Zhengnian
authors.initials: Z
authors.lastname: Ding
mesh_terms: D000779:Anesthetics, Local / Q000009:adverse effects* / Q000378:metabolism; D051017:Apoptosis Regulatory Proteins / Q000378:metabolism; D001343:Autophagy / Q000502:physiology*; D000071186:Beclin-1 / Q000378:metabolism; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000502:physiology; D006801:Humans; D009447:Neuroblastoma / Q000378:metabolism; D034741:RNA, Small Interfering / Q000378:metabolism; D038762:Ribosomal Protein S6 Kinases, 70-kDa / Q000378:metabolism*; D015398:Signal Transduction / Q000502:physiology; D058570:TOR Serine-Threonine Kinases / Q000378:metabolism*; D000077005:Tuberous Sclerosis Complex 2 Protein; D025521:Tumor Suppressor Proteins / Q000378:metabolism*; D015854:Up-Regulation / Q000502:physiology
chemical_list: D000779:Anesthetics, Local; D051017:Apoptosis Regulatory Proteins; D000071186:Beclin-1; D034741:RNA, Small Interfering; C000624653:TSC2 protein, human; D000077005:Tuberous Sclerosis Complex 2 Protein; D025521:Tumor Suppressor Proteins; C546842:MTOR protein, human; D038762:Ribosomal Protein S6 Kinases, 70-kDa; D058570:TOR Serine-Threonine Kinases
keywords: autophagy; local anaesthetics; neurotoxicity; tuberin/mTOR/p70S6K signalling