Temporal Expression Profiling of Global Long Noncoding RNA and mRNA during Development in Pig Whole-blood

Blood is the pipeline of the immune system. Assessing changes in transcript abundance in blood on a genome-wide scale affords a comprehensive view of the status of the immune system during development. However, little is known about the changes of gene expression in blood across multiple developmental stages in pigs. In this study, we performed transcriptomic analysis of messenger RNA (mRNA) and long noncoding RNA (lncRNA) expressed in whole-blood tissue from pigs of natal, suckling, weaning, sexual maturity and adult stages. A total of 5,946 lncRNA and 12,354 mRNA transcripts were identified to be substantially expressed. Short time-series expression miner (STEM) and functional enrichment analysis showed that genes with the greatest variation of expression levels between suckling period (0, 7 and 28 days) and the late stage of development (180 days and 2 years) might function in transcription, immune function, and apoptotic process. Functional prediction indicated the expression correlation and functional relatedness between mRNAs and lncRNAs. Additionally, a number of T cell-related genes were continuously up-regulated during lactation, suggesting this phase is significant for the establishment of piglet adaptive immunity. Notably, the TCONS_00192752 and TCONS-00086451 lncRNA might promote blood immune development by up-regulating the tumor necrosis factor receptor-associated factor 3 (TRAF3) and nuclear factor of activated T-cells cytoplasmic 2 (NFATC2) expression, respectively. Our research provides the first catalog of the developing pig whole-blood, and will accelerate clinical researches of immune system development with pig models. Ten healthy female pigs were used to simulate the blood immune system development. In the 0 day, 7 day, 28day, 180day and 2 year groups, there were two pigs of similar weight obtained after birth in each group. Pig whole-blood tissues collected from each pig and frozen immediately in liquid nitrogen and stored at -80°C until required for RNA extraction, sequencing and transcriptome analysis.