title: Effects of N-stearoyl-L-tyrosine on the hippocampal ubiquitin-proteasome system in rats with chronic cerebral hypoperfusion.
abstract: OBJECTIVE
  Chronic cerebral hypoperfusion (CCH) leads to neurodegeneration and cognitive impairment. Ubiquitinated protein aggregates are commonly present in neurodegenerative disorders and are believed to cause neuronal degeneration. Here, we investigated the effects of N-stearoyl-L-tyrosine (NSTyr) on the hippocampal ubiquitin-proteasome system (UPS) in rats with CCH.
  
  
  METHODS
  After induction of CCH, NSTyr was intraperitoneally administered daily for 3 months. Protein aggregation was analyzed by ethanolic phosphotungstic acid (EPTA) electron microscopy (EM), immunogold EM, laser-scanning confocal microscopy, and Western blot. Proteasome peptidase activity was measured by peptidase activity assays.
  
  
  RESULTS
  By using EPTA EM, immunogold EM and high-resolution laser-scanning confocal microscopy, we found that CCH resulted in the accumulation of ubiquitinated protein aggregates in rat hippocampal CA1 neurons. Western blot revealed that the levels of free ubiquitin were significantly reduced and that the levels of ubiquitinated proteins were markedly increased in the hippocampus of CCH rats. Direct activity measurements demonstrated that proteasome peptidase activity in the hippocampal region of rats was decreased after CCH induction. In the hippocampal tissue of CCH rats treated with NSTyr, however, ubiquitinated protein aggregates decreased and proteasome peptidase activity increased.
  
  
  CONCLUSIONS
  These data indicate that NSTyr may exert protective effects on rat hippocampal UPS function via endogenous regulation.
authors.affiliation: Tongji University, Shanghai, China.
authors.forename: Jian
authors.initials: J
authors.lastname: Hai
authors.forename: Qi
authors.initials: Q
authors.lastname: Lin
authors.forename: Yi-Fang
authors.initials: YF
authors.lastname: Wu
authors.forename: Xiao-Song
authors.initials: XS
authors.lastname: Huang
authors.forename: Gui-Yun
authors.initials: GY
authors.lastname: Zhang
authors.forename: Fei
authors.initials: F
authors.lastname: Wang
mesh_terms: D000818:Animals; D056547:CA1 Region, Hippocampal / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D002540:Cerebral Cortex / Q000098:blood supply*; D009474:Neurons / Q000166:cytology / Q000378:metabolism; D046988:Proteasome Endopeptidase Complex / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D014443:Tyrosine / Q000031:analogs & derivatives* / Q000494:pharmacology; D025801:Ubiquitin / Q000378:metabolism*
chemical_list: D025801:Ubiquitin; D014443:Tyrosine; C087584:N-stearoyltyrosine; D046988:Proteasome Endopeptidase Complex