Exposure to early-life stress (ELS) increases risk for poor mental and physical health outcomes that emerge at different stages across the lifespan. Yet, how age interacts with ELS to impact the expression of specific phenotypes remains largely unknown. An established limited-bedding paradigm was used to induce ELS in mouse pups over the early postnatal period. Initial analyses focused on the hippocampus, based on documented sensitivity to ELS in humans and various animal models, and the large body of data reporting anatomical and physiological outcomes in this structure using this ELS paradigm. An unbiased discovery proteomics approach revealed distinct adaptations in the non-nuclear hippocampal proteome in male versus female offspring at two distinct developmental stages: juvenile and adult. Gene ontology and KEGG pathway analyses revealed significant enrichment in proteins associated with mitochondria and the oxidative phosphorylation (OXPHOS) pathway in response to ELS in female hippocampus only. To determine whether the protein adaptations to ELS reflected altered function, mitochondrial respiration (driven through complexes II-IV) and complex I activity were measured in isolated hippocampal mitochondria using a Seahorse X96 Flux analyzer and immunocapture ELISA, respectively. ELS had no effect on basal respiration in either sex at either age. In contrast, ELS increased OXPHOS capacity in juvenile males and females, and reduced OXPHOS capacity in adult females but not adult males. A similar pattern of ELS-induced changes was observed for complex I activity. These data suggest that initial adaptations in juvenile hippocampus due to ELS were not sustained in adults. Mitochondrial adaptations to ELS were also exhibited peripherally by liver. Overall, the temporal distinctions in mitochondrial responses to ELS show that ELS-generated adaptations and outcomes are complex over the lifespan. This may contribute to differences in the timing of appearance of mental and physical disturbances, as well as potential sex differences that influence only select outcomes.

暴露于生命早期压力（ELS）中会增加在整个生命周期的不同阶段出现的不良心理和身体健康状况的风险。然而，年龄如何与ELS相互作用以影响特定表型的表达仍然未知。在出生后早期，已建立的有限铺垫范例用于在小鼠幼鼠中诱导ELS。基于已记录的人类和各种动物模型对ELS的敏感性，以及基于使用此ELS范例在此结构中解剖和生理结果报告的大量数据，初步分析的重点是海马体。无偏见的发现蛋白质组学方法揭示了在两个不同的发育阶段：雄性和雌性后代，无核海马蛋白质组在雄性和雌性后代中具有不同的适应性。基因本体论和KEGG通路分析表明，仅在雌性海马中，与线粒体相关的蛋白质和氧化磷酸化（OXPHOS）通路中的蛋白质显着富集，从而响应ELS。为了确定蛋白质对ELS的适应性是否反映了功能的改变，分别使用Seahorse X96 Flux分析仪和免疫捕获ELISA在分离的海马线粒体中测量了线粒体呼吸作用（通过复合物II-IV驱动）和复合物I活性。在任何年龄，ELS对男女的基础呼吸都没有影响。相反，ELS增加了成年男性和女性的OXPHOS能力，降低了成年女性的OXPHOS能力，但没有降低成年男性的OXPHOS能力。对于复杂的I活性，观察到了类似的ELS诱导变化模式。这些数据表明在成年人中由于ELS引起的海马幼体的初始适应没有持续。肝脏还显示了线粒体对ELS的适应性。总体而言，线粒体对ELS反应的时间差异表明，ELS产生的适应性和结果在整个生命周期中都很复杂。这可能会导致精神和身体不适出现时间的差异，以及可能仅影响特定结局的潜在性别差异。