Proteomic and mitochondrial adaptations to early-life stress are distinct in juveniles and adults

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.

Hypocrellin A-based photodynamic action induces apoptosis in A549 cells through ROS-mediated mitochondrial signaling pathway

Over recent decades, many studies have reported that hypocrellin A (HA) can eliminate cancer cells with proper irradiation in several cancer cell lines. However, the precise molecular mechanism underlying its anticancer effect has not been fully defined. HA-mediated cytotoxicity and apoptosis in human lung adenocarcinoma A549 cells were evaluated after photodynamic therapy (PDT). A temporal quantitative proteomics approach by isobaric tag for relative and absolute quantitation (iTRAQ) 2D liquid chromatography with tandem mass spectrometric (LC–MS/MS) was introduced to help clarify molecular cytotoxic mechanisms and identify candidate targets of HA-induced apoptotic cell death. Specific caspase inhibitors were used to further elucidate the molecular pathway underlying apoptosis in PDT-treated A549 cells. Finally, down-stream apoptosis-related protein was evaluated. Apoptosis induced by HA was associated with cell shrinkage, externalization of cell membrane phosphatidylserine, DNA fragmentation, and mitochondrial disruption, which were preceded by increased intracellular reactive oxygen species (ROS) generations. Further studies showed that PDT treatment with 0.08 µmol/L HA resulted in mitochondrial disruption, pronounced release of cytochrome c, and activation of caspase-3, -9, and -7. Together, HA may be a possible therapeutic agent directed toward mitochondria and a promising photodynamic anticancer candidate for further evaluation.

Identification of diagnostic markers involved in the pathogenesis of gastric cancer through iTRAQ-based quantitative proteomics

We provide detailed datasets from our analysis of proteins that are differentially expressed in gastric cancer tissues compared with adjacent normal gastric tissues, as identified by iTRAQ-based quantitative proteomics. Also included is a set of representative images of immunohistochemical staining of gastric cancer tissues showing four levels of expression of fatty acid binding protein (FABP1) and fatty acid synthase (FASN). The data presented in this paper support the research article "Quantitative proteomic analysis reveals that proteins required for fatty acid metabolism may serve as diagnostic markers for gastric cancer" (Jiang et al., 2017) [1]. We expect that the data will contribute to the identification of sensitive and specific biomarkers for early detection of gastric cancer.

Comparative proteomics analyses of intraspecific differences in the response of Stipa purpurea to drought

Stipa purpurea is widely distributed along a large precipitation gradient on the Tibetan Plateau. This implies that S. purpurea from different populations may have different responses to drought stress. To explore this we compared the morphological and physiological changes of S. purpurea seedlings cultivated from seeds from Gar County and Nagqu County after 7 and 14 days of drought stress and subsequent re-watering. The results showed that S. purpurea plants from the more arid Gar area were more tolerant to drought stress than that from Nagqu. To investigate the potential mechanisms underlying this difference, we used iTRAQ quantitative proteomics technology to analyze protein dynamics in S. purpurea samples treated with 7 days of drought stress and subsequent re-watering. The results indicated that, during the process of drought and re-watering treatments, there were differentially expressed proteins in either or both S. purpurea populations. These differential proteins were divided into 24 functional categories that were mainly associated with stress response, the antioxidant system, photosynthesis, carbohydrate metabolism, and post-translational modifications. According to these results, we concluded that the molecular basis of stronger drought resistance likely lies in the specific up-regulation or higher expression of many proteins involved in stress response, the antioxidant system, post-translational modification and osmotic regulation in S. purpurea from Gar County compared with that from Nagqu. This study improves our understanding of the intraspecific differences in drought resistance within S. purpurea populations, which helps to understand the distribution of S. purpurea along the moisture gradient, as well as the effect of climate change on this species.