GSE112152
Transcriptome analysis of swine spleen after infection with PCV2
Purpose: Post-weaning multisystemic wasting syndrome (PMWS) is a disease associated with porcine circovirus type 2 (PCV2) infection. One main feature of PMWS is seriously decreased lymphocyte in lymphoid tissues. This research aims to investigate the molecular mechanism of evident lymphocyte depletion in spleen from Yorkshire x Landrace (YL) pigs after infection with PCV2. Methods: At the age of 6 weeks, 15 piglets of Laiwu (LW) and YL pigs were assigned randomly into two groups, respectively: 10 infected pigs and 5 uninfected pigs. Spleen tissues of each group were collected at 35 days post infection with PCV2. Three PCV2-infected YL pigs with apparently pathologic characteristics and mock-infected YL pigs were selected for RNA sequencing, respectively. The RNA extraction, library construction and RNA-Seq were performed on the Illumina HiSeq2500 at Beijing BioMarker Technologies (Beijing, China).Differential expression genes (DEGs) were filtrated from the result of transcriptome. The quantitative real-time PCR was performed to validate the expression patterns of candidate DEGs between LW and YL pigs. Results: The clean reads percolated from the raw reads were mapped to Sus scrofa genome (Sscrofa10.2) using Tophat2 software. The efficiency of alignment was about 76% between the six samples and reference genome, and approximate 50% clean reads were perfectly matched to pig genome. Two samples with high R-squared value (T1-T3: 0.98; T5-T6: 0.97) from PCV2 and mock-infected YL pigs, respectively, was performed differential expression analysis through DESeq after biologic repetition correlation detection. With the criterion of log FC (fold change) > 1.5 and of P value < 0.05, 90 significantly differentially expressed genes were identified between the two groups, of which 57 were up-regulated and 33 were down-regulated. Eleven candidate DEGs were confirmed by quantitative real-time PCR, which expression pattern were generally in accordance with the results of RNA-seq. Conclusions: Many DEGs participate in immune response and some of them are involved in cells proliferation or apoptosis, such as CD81, HGF, CXCL13, KLF11, PSMD4, CYCS and ACTC1. The expression changes of these DEGs may cause the lymphocyte depletion in spleen after challenge with PCV2. Overall design: Spleen mRNA transcriptome of 11-week old PCV2-infected and mock-infected pigs was generated by RNA sequencing, in triplicate, using Illumina HiSeq 2500.