Effect of selenium nanoparticles on alternative splicing in heat-stressed rainbow trout primary hepatocytes

Alternative splicing (AS) is a ubiquitous post-transcriptional regulatory mechanism in eukaryotes that generates multiple mRNA isoforms from a single gene, increasing diversity of mRNAs and proteins that are essential for eukaryotic developmental processes and responses to environmental stress. Results showed that a total of 37,463 AS events were identified in rainbow trout hepatocytes. In addition, a total of 364 differential alternative splicing (DAS) events were identified in hepatocytes under selenium nanoparticles (SeNPs) and 3632 DAS events were identified under a combination of SeNPs and heat stress (24 degrees C). Gene Ontology (GO) enrichment showed that some subcategories "immune effector processes", "response to stimuli" and "antioxidant activity" were associated with immunity, abiotic stimuli and antioxidants. Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment showed that differentially expressed genes (DEGs) were significantly enriched in spliceosomes by adding SeNPs in heat-stressed hepatocytes. Splicing factor family (SRSF3, SRSF7, SRSF9, U2AF1 and U2AF2) and pre-RNA splicing factors (ACIN1 and PPRF18) were significantly upregulated and promoted AS. Furthermore, addition of SeNPs activated the phosphatidylinositol signaling system and upregulated the related genes PI4KA, DGKH, ITPK1 and Ocrl, and thus attenuated the inflammatory response to heat stress and enhanced resistance to heat stress by activating the adherent plaque kinase-PI3K-Akt signaling pathway and calcium channels. Those findings suggested that AS could be an essential regulatory mechanism in adaptation of rainbow trout to heatstressed environments.