No abstract

Xu, Jin, Shenhan Gao, Mingyuan Xin, Wenjie Chen, Kaikun Wang, Wenjing Liu, Xinzong Yan, Sinan Peng, and Yanming Ren. Comparative tandem mass tag-based quantitative proteomics analysis of liver against chronic hypoxia: molecular insights into metabolism in rats. High Alt Med Biol . 24:49–58, 2023. Objective: Using a metabolomic approach, we uncovered key regulators in metabolism from tandem mass tag (TMT)-based proteomic analysis in animals chronically exposed to hypoxia. Methods: Sixteen Sprague–Dawley rats ( n = 8 per group) were exposed to chronic normoxia or hypoxia (380 mmHg corresponding to a simulated altitude of 5,500 m) for 35 consecutive days. Hypoxia-induced alterations in metabolic pathways were analyzed from TMT-based proteomic analysis, complemented by western blot validation of key regulators. Results: We profiled biochemical parameters and serum lipids, found that serum alanine aminotransferase and blood glucose were not significantly changed due to chronic hypoxia. However, serum triglycerides, total cholesterol, high-density lipoprotein, and low-density lipoprotein (LDL) were significantly affected by chronic hypoxia. And the levels of LDL nearly doubled ( p < 0.05) after hypoxia exposure for 35 days. Through Kyoto Encyclopedia of Genes and Genomes classification, we found several metabolic pathways were enriched, including lipid metabolism, cofactor and vitamin metabolism, amino acids metabolism, carbohydrate metabolism, and energy metabolism. To explore the potential functions of proteins in metabolic pathways that become a coordinated shift under chronic hypoxic conditions, Gene Ontology and pathway analysis were carried out on differentially expressed proteins. As the co-expression network shown in Figure, we identified the most significant differentially expressed proteins after chronic hypoxic changes in the livers of rats. Furthermore, we validated the gene expression profiles at the protein level using western blot. Results of western blot were in accordance with our quantitative polymerase chain reaction findings. The levels of fatty acid synthase and aquaporin 1 were significantly downregulated after 35 days and the levels of ATP citrate lyase, 2′-5′-oligoadenylate synthetase 1A, aldehyde dehydrogenase 2, and Ras-related protein Rap-1A were significantly upregulated after 35 days. Conclusions: Although this study cannot completely account for all the molecular mechanisms in rats, we provide a good analysis of protein expression and profiling of rats under chronic hypoxia conditions.

Background: Acute hypoxia consistently results in altitude sickness and can be fatal. Until present, no studies focusing on global proteomic changes induced by acute hypoxia have been reported. Here, we combined animal experiments and tandem mass tag (TMT)-based proteomic analysis to identify metabolic changes as a result of acute hypoxia. Methods: We first generated a rat model under acute hypoxia conditions, and combined animal experiments and TMT-based proteomics to identify metabolic changes under acute hypoxia. Then we used qPCR analyses to validate the key regulators, and present a schematic model of acute reactions occurring in the livers of rats subjected to acute hypoxia challenge. Results: We identified a large number of acute hypoxic responsive proteins in diverse biological pathways, which helped unveil the different mechanisms involved in hypoxia responses in rats. These pathways included those of peroxisome, peroxisome proliferator-activated receptor (PPAR) signaling, lipid metabolism, glycolysis/gluconeogenesis, and amino acid metabolism. According to data obtained from proteomic analysis, rats were able to maintain normal physical activity as a response to acute hypoxia by activating their catabolic capacity in order to get more energy (e.g., lipolysis and amino acid catabolism), and decreasing biosynthesis to reduce energy consumption (e.g., biosynthesis of amino acids and lipids). Conclusions: We identified a large number of acute hypoxia-responsive proteins associated with diverse biological pathways, and showed rats quickly respond to acute hypoxia by activating lipid biosynthesis to increase lipid storage, and reducing lipolysis to reduce energy consumption. The observed hypoxia-related changes in the liver proteome of rats provide a deeper understanding on the mammalian response to hypoxia.

Alveolar Echinococcosis is a globally widespread zoonotic disease caused by the larval stage of Echinococcus multilocularis (E.m.) and is seriously harmful to human health. In our previous studies, we found that Em-EMY162 has good protective and therapeutic effects against E.m. and the dominant epitopes of Em-EMY162 and Em-TSP3 were also identified. In this study, a mucosal immunity multi-epitope vaccine LTB-ETBM targeting both Em-EMY162 and Em-TSP3 was designed and constructed. Furtherly the immunogenicity and immunoprotection were evaluated in E.m. infected mice model. LTB-ETBM could induce the mice generating high levels of specific IgG against Em-EMY162 and Em-TSP3. Furtherly a Th1/Th2 mixed lymphocyte responses to LTB-ETBM was identified. Moreover, the LTB-ETBM significantly inhibited the formation of cysts in mice challenged with 1000 E.m. protoscoleces. In a therapeutic mouse model injected intraperitoneally with 1000 protoscoleces, vaccination with LTB-ETBM using either Freund's or CpG as an adjuvant significantly decreased the growth of protoscoleces and the formation of cysts. LTB-ETBM may be efficacious for activating the immune system and for use as a prophylactic or therapeutic agent against E.m. infection.

Acute hypoxia consistently results in altitude sickness and can be fatal. Until present, no studies focusing on global proteomic changes induced by acute hypoxia have been reported. Here, we combined animal experiments and tandem mass tag (TMT)-based proteomic analysis to identify metabolic changes as a result of acute hypoxia. We first generated a rat model under acute hypoxia conditions. Then we used qPCR analyses to validate the key regulators, and present a schematic model of acute reactions occurring in the livers of rats subjected to acute hypoxia challenge. We identified a large number of acute hypoxic responsive proteins in diverse biological pathways, which helped unveil the different mechanisms involved in hypoxia responses in rats. According to data obtained from proteomic analysis, rats were able to maintain normal physical activity as a response to acute hypoxia by activating their catabolic capacity in order to get more energy, and decreasing biosynthesis to reduce energy consumption. We identified a large number of acute hypoxia-responsive proteins associated with diverse biological pathways, and showed rats quickly respond to acute hypoxia by activating lipid biosynthesis to increase lipid storage, and reducing lipolysis to reduce energy consumption.