Gene array analysis of PD-1H overexpressing monocytes reveals a pro-inflammatory profile (INC2P.417)

Abstract

Abstract We have previously reported that overexpression of Programmed Death -1 Homolog (PD-1H) in human monocytes leads to activation and spontaneous secretion of multiple pro inflammatory cytokines. Here we evaluated changes in monocytes gene expression after enforced PD-1H expression by gene array. Total RNA isolated from PD-1H-expressing and control monocytes were analyzed with human Illumina HT-12 v4 Expression BeadChip. Fold change of genes were confirmed by real time PCR. Data revealed alterations in 51 potential candidate genes that relate to immune response, cell adhesion and metabolism. Genes corresponding to pro-inflammatory cytokines showed the highest upregulation. Compared to vector control, PD-1H induced a 7, 3.2, 3.0, 5.8, 4.4 and 3.1 fold upregulation of TNF-α, IL-1beta, IFN-α, γ, λ and IL-27 respectively. Further, the difference was abrogated in presence of specific but not scrambled siRNA. The data are in agreement with our cytometric bead array analysis showing induction of proinflammatory cytokines, IL-6, IL-1β and TNF-α by PD-1H. Other genes related to inflammation, including transglutaminase 2, the transcription factor NF-kB (p65 and p50) and toll like receptors 3 and 4 were also upregulated 5, 4.5 and 2.5 fold respectively. The analysis also revealed a novel set of previously unreported genes that need to be further mined and validated. We conclude that PD-1H functions to enhance monocyte activation.