title: The dopaminergic stabilizer, (-)-OSU6162, rescues striatal neurons with normal and expanded polyglutamine chains in huntingtin protein from exposure to free radicals and mitochondrial toxins.
abstract: Huntington's disease (HD) is a neurodegenerative disease characterized by progressive motor, cognitive and psychiatric deficits, associated with predominant loss of striatal neurons and caused by a polyglutamine expansion in the huntingtin protein. There is so far neither cure nor approved disease-slowing therapy for HD, though recent clinical studies have shown a beneficial long-term effect of pridopidine in patients with HD. The nature of this effect, purely symptomatic or, in addition, neuroprotective, is difficult to elucidate in clinical trials. Pridopidine and (-)-OSU6162 are members of a new family of compounds referred to as dopaminergic stabilizers, which normalize abnormal dopamine neurotransmission. We investigated the effects of (-)-OSU6162 on huntingtin knocked-in striatal neurons in culture. Control neurons had normal full-length huntingtin with 7 glutamines while "mutant" neurons had large expansions (Q=111). We studied the dose-effect curves of (-)-OSU6162 on mitochondrial activity, LDH levels, necrosis and apoptosis in untreated Q7 and Q111 cells. In addition, we investigated the effects of (-)-OSU6162 on Q7 and Q111 neurons challenged with different neurotoxins such as sodium glutamate, H(2)O(2), rotenone and 3-nitropropionic acid (3NP). As we found prevention of toxicity of some of these neurotoxins, we investigated the putative neuroprotective mechanisms of action of (-)-OSU6162 measuring the effects of this dopaminergic stabilizer on expression and release of BDNF, the ratios of Bcl2/Bax proteins and of p-ERK/ERK, the levels of chaperones and GSH, and the effects of (-)-OSU6162 on dopamine uptake and release. We found that (-)-OSU6162, 3-150 μM, produces a dose dependent increase of mitochondrial activity and a reduction of cell death. (-)-OSU6162 does not change glutamate toxicity, but it partially prevents that of H(2)O(2), rotenone and 3-nitropropionic acid. (-)-OSU6162 increases the intracellular levels of BDNF and Bcl2/Bax and decreases those of p-ERK/ERK and CHIP in Q111 cells. (-)-OSU6162 increased (3)H-dopamine uptake and amphetamine-induced (3)H-dopamine release in E13 mouse mid brain neurons. Our studies demonstrate that (-)-OSU6162 improves survival and mitochondrial function in striatal Q111 neurons and the resistance of these cells to several striatal neurotoxins, suggesting that (-)-OSU6162 and related compounds should be tested for neuroprotection in animal models and, eventually, in patients with HD.
authors.affiliation: Department of Neurology, Hospital Ramón y Cajal, Madrid, Spain.
authors.forename: C
authors.initials: C
authors.lastname: Ruiz
authors.forename: M J
authors.initials: MJ
authors.lastname: Casarejos
authors.forename: I
authors.initials: I
authors.lastname: Rubio
authors.forename: S
authors.initials: S
authors.lastname: Gines
authors.forename: M
authors.initials: M
authors.lastname: Puigdellivol
authors.forename: J
authors.initials: J
authors.lastname: Alberch
authors.forename: M A
authors.initials: MA
authors.lastname: Mena
authors.forename: J G
authors.initials: JG
authors.lastname: de Yebenes
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D019208:Brain-Derived Neurotrophic Factor / Q000378:metabolism; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D003342:Corpus Striatum / Q000166:cytology*; D004298:Dopamine / Q000378:metabolism; D015259:Dopamine Agents / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D004622:Embryo, Mammalian; D004797:Enzyme-Linked Immunosorbent Assay; D018698:Glutamic Acid / Q000633:toxicity; D005978:Glutathione / Q000378:metabolism; D006801:Humans; D000071058:Huntingtin Protein; D006861:Hydrogen Peroxide / Q000633:toxicity*; D051379:Mice; D008810:Mice, Inbred C57BL; D009154:Mutation / Q000235:genetics; D009419:Nerve Tissue Proteins / Q000737:chemistry / Q000235:genetics*; D009474:Neurons / Q000187:drug effects*; D010455:Peptides / Q000235:genetics / Q000378:metabolism*; D010880:Piperidines / Q000494:pharmacology*; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D012402:Rotenone / Q000633:toxicity*; D014162:Transfection / Q000379:methods; D014316:Tritium / Q000378:metabolism
chemical_list: D019208:Brain-Derived Neurotrophic Factor; D015259:Dopamine Agents; C086055:HTT protein, human; D000071058:Huntingtin Protein; D009419:Nerve Tissue Proteins; D010455:Peptides; D010880:Piperidines; D019253:Proto-Oncogene Proteins c-bcl-2; D012402:Rotenone; C109513:OSU 6162; D014316:Tritium; C097188:polyglutamine; D018698:Glutamic Acid; D006861:Hydrogen Peroxide; D005978:Glutathione; D004298:Dopamine