title: The protective role of AMP-activated protein kinase in alpha-synuclein neurotoxicity in vitro.
abstract: In the present study, we investigated the role of the main intracellular energy sensor, AMP-activated protein kinase (AMPK), in the in vitro neurotoxicity of α-synuclein (ASYN), one of the key culprits in the pathogenesis of Parkinson's disease. The loss of viability in retinoic acid-differentiated SH-SY5Y human neuroblastoma cells inducibly overexpressing wild-type ASYN was associated with the reduced activation of AMPK and its activator LKB1, as well as AMPK target Raptor. ASYN-overexpressing rat primary neurons also displayed lower activity of LKB1/AMPK/Raptor pathway. Restoration of AMPK activity by metformin or AICAR reduced the in vitro neurotoxicity of ASYN overexpression, acting independently of the prosurvival kinase Akt or the induction of autophagic response. The conditioned medium from ASYN-overexpressing cells, containing secreted ASYN, as well as dopamine-modified or nitrated recombinant ASYN oligomers, all inhibited AMPK activation in differentiated SH-SY5Y cells and reduced their viability, but not in the presence of metformin or AICAR. The RNA interference-mediated knockdown of AMPK increased the sensitivity of SH-SY5Y cells to the harmful effects of secreted ASYN. AMPK-dependent protection from extracellular ASYN was also observed in rat neuron-like pheochromocytoma cell line PC12. These data demonstrate the protective role of AMPK against the toxicity of both intracellular and extracellular ASYN, suggesting that modulation of AMPK activity may be a promising therapeutic strategy in Parkinson's disease.
authors.affiliation: Institute of Medical and Clinical Biochemistry, School of Medicine, University of Belgrade, Pasterova 2, Belgrade, Serbia.
authors.forename: Marija
authors.initials: M
authors.lastname: Dulovic
authors.affiliation: Institute of Medical and Clinical Biochemistry, School of Medicine, University of Belgrade, Pasterova 2, Belgrade, Serbia.
authors.forename: Maja
authors.initials: M
authors.lastname: Jovanovic
authors.affiliation: Division of Basic Neurosciences, Biomedical Research Foundation of the Academy of Athens, Athens, Greece.
authors.forename: Maria
authors.initials: M
authors.lastname: Xilouri
authors.affiliation: Division of Basic Neurosciences, Biomedical Research Foundation of the Academy of Athens, Athens, Greece; Second Department of Neurology, University of Athens Medical School, Athens, Greece.
authors.forename: Leonidas
authors.initials: L
authors.lastname: Stefanis
authors.affiliation: Institute for Biological Research, University of Belgrade, Belgrade, Serbia.
authors.forename: Ljubica
authors.initials: L
authors.lastname: Harhaji-Trajkovic
authors.affiliation: Institute of Histology and Embryology, School of Medicine, University of Belgrade, Belgrade, Serbia.
authors.forename: Tamara
authors.initials: T
authors.lastname: Kravic-Stevovic
authors.affiliation: Institute of Microbiology and Immunology, School of Medicine, University of Belgrade, Dr. Subotica 1, 11000 Belgrade, Serbia.
authors.forename: Verica
authors.initials: V
authors.lastname: Paunovic
authors.affiliation: Department of Biochemistry, College of Medicine and Health Science, United Arab Emirates University, Al Ain, United Arab Emirates.
authors.forename: Mustafa T
authors.initials: MT
authors.lastname: Ardah
authors.affiliation: Department of Biochemistry, College of Medicine and Health Science, United Arab Emirates University, Al Ain, United Arab Emirates; Faculty of Medicine, King Abdulaziz University, Jeddah, Saudi Arabia.
authors.forename: Omar M A
authors.initials: OM
authors.lastname: El-Agnaf
authors.affiliation: Clinic for Neurology CCS, School of Medicine, University of Belgrade, Serbia.
authors.forename: Vladimir
authors.initials: V
authors.lastname: Kostic
authors.affiliation: Institute of Medical and Clinical Biochemistry, School of Medicine, University of Belgrade, Pasterova 2, Belgrade, Serbia. Electronic address: ivanka@med.bg.ac.rs.
authors.forename: Ivanka
authors.initials: I
authors.lastname: Markovic
authors.affiliation: Institute of Microbiology and Immunology, School of Medicine, University of Belgrade, Dr. Subotica 1, 11000 Belgrade, Serbia. Electronic address: vtrajkovic@med.bg.ac.rs.
authors.forename: Vladimir
authors.initials: V
authors.lastname: Trajkovic
mesh_terms: D000091162:AMP-Activated Protein Kinase Kinases; D055372:AMP-Activated Protein Kinases / Q000235:genetics / Q000378:metabolism*; D000620:Aminoimidazole Carboxamide / Q000031:analogs & derivatives / Q000494:pharmacology; D000818:Animals; D016923:Cell Death / Q000187:drug effects; D002454:Cell Differentiation / Q000187:drug effects / Q000235:genetics; D002478:Cells, Cultured; D002540:Cerebral Cortex / Q000166:cytology; D017077:Culture Media, Conditioned / Q000494:pharmacology; D053938:DNA Fragmentation; D004622:Embryo, Mammalian; D006801:Humans; D007004:Hypoglycemic Agents / Q000494:pharmacology; D008687:Metformin / Q000494:pharmacology; D009447:Neuroblastoma / Q000473:pathology / Q000648:ultrastructure; D009474:Neurons / Q000187:drug effects* / Q000648:ultrastructure; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D034741:RNA, Small Interfering / Q000494:pharmacology; D051381:Rats; D012265:Ribonucleotides / Q000494:pharmacology; D014212:Tretinoin / Q000494:pharmacology; D051844:alpha-Synuclein / Q000235:genetics / Q000378:metabolism*
chemical_list: D017077:Culture Media, Conditioned; D007004:Hypoglycemic Agents; D034741:RNA, Small Interfering; D012265:Ribonucleotides; D051844:alpha-Synuclein; D000620:Aminoimidazole Carboxamide; D014212:Tretinoin; D008687:Metformin; D017346:Protein Serine-Threonine Kinases; C488755:Stk11 protein, rat; D000091162:AMP-Activated Protein Kinase Kinases; D055372:AMP-Activated Protein Kinases; C031143:AICA ribonucleotide
keywords: AICAR; AMPK; Akt; Alpha-synuclein; Autophagy; Metformin; Neuroprotection; Neurotoxicity