Genomic variant in porcine TNFRSF1A gene and its effects on TNF signaling pathway in vitro

Our initial genome-wide association study (GWAS) revealed the presence of single nucleotide polymorphisms (SNPs) related to immune traits in the tumor necrosis factor receptor superfamily member 1A (TNFRSF1A) gene, suggesting the association of this gene with immune function in pigs. To better understand the immune functions of the TNFRSF1A gene, SNPs within the TNFRSF1A gene were detected by sequencing. One SNP (c.1394C > T) in exon 6 of TNFRSF1A was identified, and association analysis in two pig populations was subsequently performed. The results showed that this SNP was significantly associated with CD4^-CD8^-CD3^-, CD4⁺CD8^-CD3⁺, and CD4⁺/CD8⁺ (P = 0.0038, P = 0.0007, and P = 0.0076, respectively). Based on quantitative real-time polymerase chain reaction (RT-qPCR), the TNFRSF1A mRNA was shown to be widely expressed in six different tissues. Finally, functional verification of the TNFRSF1A gene was performed in vitro to better understand its role. RNAi was used to generate a porcine PK15 cell line with a silenced TNFRSF1A gene, and a vector was also constructed to assess overexpression of TNFRSF1A. RT-qPCR was then used to detect changes in the expression levels of five critical genes. Our results indicated that TNFRSF1A activated the TNF signaling pathway and inhibited the NFκB signaling pathway in vitro. These findings provide evidence for an immune-related regulatory function for porcine TNFRSF1A.