Hai Jian, Lin Qi, Wu Yi-Fang, Huang Xiao-Song, Zhang Gui-Yun, Wang Fei
Tongji University, Shanghai, China.
Neurol Res. 2013 Sep;35(7):734-43. doi: 10.1179/1743132812Y.0000000154. Epub 2013 Mar 26.
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.
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.
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.
These data indicate that NSTyr may exert protective effects on rat hippocampal UPS function via endogenous regulation.
慢性脑灌注不足（CCH）会导致神经退行性变和认知障碍。泛素化蛋白聚集体普遍存在于神经退行性疾病中，并被认为会导致神经元变性。在此，我们研究了N-硬脂酰-L-酪氨酸（NSTyr）对CCH大鼠海马泛素-蛋白酶体系统（UPS）的影响。
诱导CCH后，每天腹腔注射NSTyr，持续3个月。通过乙醇磷钨酸（EPTA）电子显微镜（EM）、免疫金EM、激光扫描共聚焦显微镜和蛋白质印迹法分析蛋白聚集情况。通过蛋白酶活性测定来测量蛋白酶体的肽酶活性。
通过使用EPTA EM、免疫金EM和高分辨率激光扫描共聚焦显微镜，我们发现CCH导致大鼠海马CA1神经元中泛素化蛋白聚集体的积累。蛋白质印迹法显示，CCH大鼠海马中游离泛素水平显著降低，泛素化蛋白水平显著升高。直接活性测量表明，诱导CCH后大鼠海马区域的蛋白酶体肽酶活性降低。然而，在用NSTyr治疗的CCH大鼠海马组织中，泛素化蛋白聚集体减少，蛋白酶体肽酶活性增加。
这些数据表明，NSTyr可能通过内源性调节对大鼠海马UPS功能发挥保护作用。
