Effects of N-stearoyl-L-tyrosine on the hippocampal ubiquitin-proteasome system in rats with chronic cerebral hypoperfusion
Effects of N-stearoyl-L-tyrosine on the hippocampal ubiquitin-proteasome system in rats with chronic cerebral hypoperfusion
复制标题
N-硬脂酰-L-酪氨酸对慢性脑低灌注大鼠海马泛素-蛋白酶体系统的影响
DOI：
10.1179/1743132812y.0000000154
复制
发表时间：
2013-09-01
影响因子：
1.9
通讯作者：
Wang, Fei
中科院分区：
文献类型：
--
作者：
Hai, Jian;Lin, Qi;Wang, Fei
摘要目的：慢性脑低灌注(CCH)可导致神经退行性变和认知功能障碍。泛素化的蛋白质聚集体普遍存在于神经退行性疾病中，被认为是导致神经元退行性变的原因。在本实验中，我们观察了N-硬脂酰酪氨酸(N-stearoyl-L-tyroine，N-STIR)对脑出血大鼠海马泛素-蛋白酶体系统的影响。方法：诱导CCH后，每日1次给药，连续3个月。用乙醇磷钨酸(EPTA)电子显微镜(EM)、免疫金EM、激光扫描共聚焦显微镜和Western印迹分析蛋白质聚集。用多肽酶活性测定法测定蛋白酶体多肽酶活性。结果：通过EPTA EM、免疫金EM和高分辨率激光扫描共聚焦显微镜观察，我们发现CCH可导致大鼠海马CA1神经元泛素化蛋白聚集体的聚集。Western印迹结果显示，CCH大鼠海马区游离泛素水平显著降低，泛素化蛋白水平显著升高。直接活性测定表明，CCH诱导后大鼠海马区蛋白酶体多肽酶活性降低。然而，在经恩斯泰治疗的CCH大鼠的海马区，泛素化蛋白聚集体减少，蛋白酶体多肽酶活性增加。讨论：这些数据表明，NSTIR可能通过内源性调节对大鼠海马区UPS功能起到保护作用。
Abstract Objectives: 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. Discussion: These data indicate that NSTyr may exert protective effects on rat hippocampal UPS function via endogenous regulation.