Systemic administration of proteasome inhibitor protects against MPTP neurotoxicity in mice.
Dysfunction of the proteasome has been suggested to contribute in the degeneration of nigrostriatal dopaminergic neurons. Here, we investigated to determine whether systematic administration of proteasome inhibitor, carbobenzoxy-L: -gamma-t-butyl-L: -glutamyl-L: -alanyl-L: -leucinal (PSI) protects against MPTP (1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine) neurotoxicity in mice. Three administrations of MPTP at 1-h intervals to mice reduced significantly the concentration of dopamine, DOPAC (3,4-dihydroxyphenylacetic acid) and HVA (homovanillic acid) in the striatum after 5 days. In contrast, PSI (0.3 and 1.0 mg/kg) prevented a significant decrease in dopamine, DOPAC and HVA contents of the striatum 5 days after MPTP treatment. In our Western blot analysis study, PSI at a dose of 1.0 mg/kg prevented a significant decrease in TH (tyrosine hydroxylase) protein and a significant increase in glial fibrillary acidic protein 5 days after MPTP treatment. Furthermore, our immunohistochemical study showed that PSI at a dose of 1.0 mg/kg prevented a significant loss in TH immunopositive neurons in the striatum and substantia nigra 5 days after MPTP treatment. In contrast, PSI caused a significant increase in the number of intense ubiquitin immunopositive cells in the striatum and substantia nigra 5 days after MPTP treatment. These results indicate that proteasome inhibitors can protect against MPTP neurotoxicity in mice. The neuroprotective effect of PSI against dopaminergic cell damage may be mediated by the elevation of ubiquitination. Thus, our findings provide further valuable information for the pathogenesis of Parkinson's disease.
Department of Neurobiology and Therapeutics, Graduate School and Faculty of Pharmaceutical Sciences, The University of Tokushima, 1-78, Sho-machi, Tokushima, 770-8505, Japan.
Takuya
T
Oshikawa
Hayato
H
Kuroiwa
Ryohei
R
Yano
Hironori
H
Yokoyama
Naoto
N
Kadoguchi
Hiroyuki
H
Kato
Tsutomu
T
Araki
D015632:1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine / Q000494:pharmacology*; D000818:Animals; D015153:Blotting, Western; D002851:Chromatography, High Pressure Liquid; D004298:Dopamine / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000008:administration & dosage* / Q000494:pharmacology*; D005904:Glial Fibrillary Acidic Protein / Q000378:metabolism; D007150:Immunohistochemistry; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D017072:Neostriatum / Q000166:cytology / Q000187:drug effects / Q000201:enzymology; D009474:Neurons / Q000166:cytology / Q000187:drug effects* / Q000201:enzymology; D061988:Proteasome Inhibitors; D013378:Substantia Nigra / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D014446:Tyrosine 3-Monooxygenase / Q000378:metabolism; D025801:Ubiquitin / Q000378:metabolism
D004791:Enzyme Inhibitors; D005904:Glial Fibrillary Acidic Protein; D061988:Proteasome Inhibitors; D025801:Ubiquitin; D015632:1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine; D014446:Tyrosine 3-Monooxygenase; D004298:Dopamine