Early-life stress in the form of maternal separation can be associated with alterations in offspring neurodevelopment and brain functioning. Here, we aimed to investigate the potential impact of prolonged maternal separation on proteomic profiling of prefrontal cortex, hippocampus and cerebellum of juvenile and young adult rats. A special attention was devoted to proteins involved in the process of cell death and redox state maintenance. Long-Evans pups were separated from their mothers for 3 h daily over the first 3 weeks of life (during days 2–21 of age). Brain tissue samples collected from juvenile (22-day-old) and young adult (90-day-old) rats were used for label-free quantitative (LFQ) proteomic analysis. In parallel, selected oxidative stress markers and apoptosis-related proteins were assessed biochemically and by Western blot, respectively. In total, 5526 proteins were detected in our proteomic analysis of rat brain tissue. Approximately one tenth of them (586 proteins) represented those involved in cell death processes or regulation of oxidative stress balance. Prolonged maternal separation caused changes in less than half of these proteins (271). The observed alterations in protein expression levels were age-, sex- and brain region-dependent. Interestingly, the proteins detected by mass spectrometry that are known to be involved in the maintenance of redox state were not markedly altered. Accordingly, we did not observe any significant differences between selected oxidative stress markers, such as the levels of hydrogen peroxide, reduced glutathione, protein carbonylation and lipid peroxidation in brain samples from rats that underwent maternal separation and from the corresponding controls. On the other hand, a number of changes were found in cell death-associated proteins, mainly in those involved in the apoptotic and autophagic pathways. However, there were no detectable alterations in the levels of cleaved products of caspases or Bcl-2 family members. Taken together, these data indicate that the apoptotic and autophagic cell death pathways were not activated by maternal separation either in adolescent or young adult rats. Prolonged maternal separation can distinctly modulate expression profiles of proteins associated with cell death pathways in prefrontal cortex, hippocampus and cerebellum of juvenile rats and the consequences of early-life stress may last into adulthood and likely participate in variations in stress reactivity.

中文翻译：

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不同大鼠大脑区域的蛋白质组图谱揭示了延长的母体分离对参与细胞死亡相关过程的蛋白质的调节作用

母体分离形式的早期生活压力可能与后代神经发育和脑功能的改变有关。在这里，我们旨在调查延长母体分离对幼年和成年大鼠前额叶皮层，海马和小脑的蛋白质组学分析的潜在影响。特别注意涉及细胞死亡和氧化还原状态维持过程的蛋白质。在生命的前3周内（年龄在2-21岁之间），每天将Long-Evans幼崽与母亲分开3小时。从幼年（22日龄）和年轻成年（90日龄）大鼠收集的脑组织样本用于无标记定量（LFQ）蛋白质组学分析。平行地，分别通过生物化学和Western印迹评估选择的氧化应激标记和凋亡相关蛋白。在我们对大鼠脑组织的蛋白质组学分析中，总共检测到5526个蛋白质。其中约十分之一（586种蛋白质）代表那些参与细胞死亡过程或调节氧化应激平衡的蛋白质。延长的母体分离导致这些蛋白质的变化少于一半（271）。观察到的蛋白质表达水平的变化是年龄，性别和大脑区域依赖性的。有趣的是，通过质谱检测到的已知与维持氧化还原状态有关的蛋白质没有明显改变。因此，我们没有观察到所选氧化应激指标之间的任何显着差异，例如过氧化氢的水平，还原型谷胱甘肽，接受母体分离的大鼠和相应对照组的脑样本中的蛋白质羰基化和脂质过氧化。另一方面，在细胞死亡相关蛋白中发现了许多变化，主要是在凋亡和自噬途径中。但是，胱天蛋白酶或Bcl-2家族成员的裂解产物的水平没有可检测的变化。综上所述，这些数据表明在青春期或成年大鼠中，母体分离均未激活凋亡和自噬细胞死亡途径。延长的母体分离可以明显调节与额叶皮层中细胞死亡途径相关的蛋白质的表达谱，