A cell-penetrating ester of the neural metabolite lanthionine ketimine stimulates autophagy through the mTORC1 pathway: Evidence for a mechanism of action with pharmacological implications for neurodegenerative pathologies

NEUROBIOLOGY OF DISEASE

卷:84

Article

Harris-White, Marni E.^1,2  Ferbas, Kathie G.^1,3  Johnson, Ming F.¹  Eslami, Pirooz¹  Poteshkina, Aleksandra¹  Venkova, Kalina⁴  Christov, Alexandar⁴  Hensley, Kenneth^4,5 

[1] Vet Adm Greater Los Angeles Healthcare Syst, Los Angeles, CA USA

[2] Univ Calif Los Angeles, David Geffen Sch Med, Los Angeles, CA 90095 USA

[3] Pepperdine Univ, Seaver Coll, Div Nat Sci, Malibu, CA 90265 USA

[4] Univ Toledo, Med Ctr, Dept Pathol, Toledo, OH 43614 USA

[5] Univ Toledo, Med Ctr, Dept Neurosci, Toledo, OH 43614 USA

关键词: Autophagy;    mTOR complex (mTORC);    CRMP2;    DPYSL2;    Lanthionine ketimine;   

DOI  :  10.1016/j.nbd.2015.03.007

来源: Elsevier

【 摘 要 】

Autophagy is a fundamental cellular recycling process vulnerable to compromise in neurodegeneration. We now report that a cell-penetrating neurotrophic and neuroprotective derivative of the central nervous system (CNS) metabolite, lanthionine ketimine (LK), stimulates autophagy in RG2 glioma and SH-SY5Y neuroblastoma cells at concentrations within or below pharmacological levels reported in previous mouse studies. Autophagy stimulation was evidenced by increased lipidation of microtubule-associated protein 1 light chain 3 (LC3) both in the absence and presence of bafilomycin-A1 which discriminates between effects on autophagic flux versus blockage of autophagy clearance. LIKE treatment caused changes in protein level or phosphorylation state of multiple autophagy pathway proteins including mTOR; p70S6 kinase; unc-51-like-kinase-1 (ULK1); beclin-1 and LC3 in a manner essentially identical to effects observed after rapamycin treatment. The LICE site of action was near mTOR because neither LIKE nor the mTOR inhibitor rapamycin affected tuberous sclerosis complex (TSC) phosphorylation status upstream from mTOR. Confocal immunofluorescence imaging revealed that LICE specifically decreased mTOR (but not TSC2) colocalization with LAMP2(+) lysosomes in RG2 cells, a necessary event for mTORC1-mediated autophagy suppression, whereas rapamycin had no effect. Suppression of the LK-binding adaptor protein CRMP2 (collapsin response mediator protein-2) by means of shRNA resulted in diminished autophagy flux, suggesting that the LIKE action on mTOR localization may occur through a novel mechanism involving CRMP2-mediated intracellular trafficking. These findings clarify the mechanism-of-action for LIKE in preclinical models of CNS disease, while suggesting possible roles for natural lanthionine metabolites in regulating CNS autophagy. (C) 2015 Elsevier Inc All rights reserved.

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