Transcriptome Analysis of the Liver of Eospalax Fontanierii Under Hypoxia

Abstract

BackgroundHypoxia can induce cell damage, inflammation, carcinogenesis, and inhibit liver regeneration in non-adapted species. Because of their excellent hypoxia adaptation features, subterranean rodents have been widely studied to clarify the mechanism of hypoxia adaptation. Eospalax fontanierii, which is a subterranean rodent found in China, can survive for more than 10 h under 4% O2 without observable injury, while Sprague-Dawle rats can survive for less than 6 h under the same conditions. To explore the potential mechanism of hypoxia adaptation in E. fontanierii, we performed RNA-seq analysis of the liver in E. fontanierii exposed to different oxygen levels (6.5%, 10.5%, and 21%).ResultsBased on the bioinformatics analysis, 39,439 unigenes were assembled, and 56.78% unigenes were annotated using public databases (Nr, GO, Swiss-Prot, KEGG, and Pfam). In total, 725 differentially expressed genes (DEGs) were identified in the response to hypoxia; six with important functions were validated by qPCR. Those DEGs were mainly involved in processes related to lipid metabolism, steroid catabolism, glycolysis/gluconeogenesis, and the AMPK and PPAR signaling pathway. By analyzing the expression patterns of hub genes related to energy associated metabolism under hypoxia, we found that fatty acid oxidation and gluconeogenesis were increased, while protein synthesis and fatty acid synthesis were decreased. ConclusionsWe characterized the E. fontanierii liver transcriptomes and profiled the changes in gene expression in the liver under different oxygen levels. Functional enrichment analysis showed that the main functions (steroid catabolic process, lipid metabolic process, primary bile acid biosynthesis, energy production and amino acid metabolic) of the liver were regulated in response to hypoxia. We identified multiple important DEGs underlying the potential molecular adaptation mechanisms to hypoxia, including genes associated with anti-apoptosis, energy supply, anti-inflammation, and anti-oxidation. Our results provide a comprehensive understanding of the response to hypoxia in E. fontanierii, and have potential value for biomedical studies.