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Autophagy-dependent and -independent involvement of AMP-activated protein kinase in 6-hydroxydopamine toxicity to SH-SY5Y neuroblastoma cells.
Arsikin, Katarina; Kravic-Stevovic, Tamara; Jovanovic, Maja; Ristic, Biljana; Tovilovic, Gordana; Zogovic, Nevena; Bumbasirevic, Vladimir; Trajkovic, Vladimir; Harhaji-Trajkovic, Ljubica.
Afiliación
  • Arsikin K; Institute of Microbiology and Immunology, School of Medicine, University of Belgrade, Dr. Subotica 1, 11000 Belgrade, Serbia.
Biochim Biophys Acta ; 1822(11): 1826-36, 2012 Nov.
Article en En | MEDLINE | ID: mdl-22917563
The role of the main intracellular energy sensor adenosine monophosphate (AMP)-activated protein kinase (AMPK) in the induction of autophagic response and cell death was investigated in SH-SY5Y human neuroblastoma cells exposed to the dopaminergic neurotoxin 6-hydroxydopamine (6-OHDA). The induction of autophagy in SH-SY5Y cells was demonstrated by acridine orange staining of intracellular acidic vesicles, the presence of autophagosome- and autophagolysosome-like vesicles confirmed by transmission electron microscopy, as well as by microtubule-associated protein 1 light-chain 3 (LC3) conversion and p62 degradation detected by immunoblotting. 6-OHDA induced phosphorylation of AMPK and its target Raptor, followed by the dephosphorylation of the major autophagy inhibitor mammalian target of rapamycin (mTOR) and its substrate p70S6 kinase (S6K). 6-OHDA treatment failed to suppress mTOR/S6K phosphorylation and to increase LC3 conversion, p62 degradation and cytoplasmatic acidification in neuroblastoma cells in which AMPK expression was downregulated by RNA interference. Transfection of SH-SY5Y cells with AMPK or LC3ß shRNA, as well as treatment with pharmacological autophagy inhibitors suppressed, while mTOR inhibitor rapamycin potentiated 6-OHDA-induced oxidative stress and apoptotic cell death. 6-OHDA induced phosphorylation of p38 mitogen-activated protein (MAP) kinase in an AMPK-dependent manner, and pharmacological inhibition of p38 MAP kinase reduced neurotoxicity, but not AMPK activation and autophagy triggered by 6-OHDA. Finally, the antioxidant N-acetyl cysteine antagonized 6-OHDA-induced activation of AMPK, p38 and autophagy. These data suggest that oxidative stress-mediated AMPK/mTOR-dependent autophagy and AMPK/p38-dependent apoptosis could be valid therapeutic targets for neuroprotection.
Asunto(s)

Texto completo: 1 Colección: 01-internacional Base de datos: MEDLINE Asunto principal: Autofagia / Oxidopamina / Apoptosis / Proteínas Quinasas Activadas por AMP / Neuroblastoma Límite: Humans Idioma: En Revista: Biochim Biophys Acta Año: 2012 Tipo del documento: Article Pais de publicación: Países Bajos

Texto completo: 1 Colección: 01-internacional Base de datos: MEDLINE Asunto principal: Autofagia / Oxidopamina / Apoptosis / Proteínas Quinasas Activadas por AMP / Neuroblastoma Límite: Humans Idioma: En Revista: Biochim Biophys Acta Año: 2012 Tipo del documento: Article Pais de publicación: Países Bajos