Interferon-γ-mediated gene expression in porcine alveolar macrophage; An in vitro model

Alveolar macrophages (AMs) are not only important immune cell of the host, but also important target cell of a variety of respiratory pathogens. They play an important role in defense against pathogen invasion and in maintaining tissue balance. Interferon (IFN)-γ is a well known multipotent cytokine that has antiviral and antibacterial immune activity and enhances antigen presentation. To better reveal the biological processes of porcine AMs activated by IFN-γ, transcriptomic analysis was performed using Illumina HiSeqTM technique. The results identified 2,248 differentially expressed genes (DEGs), of which 753 were upregulated and 1,495 were downregulated, in porcine AMs 12 h after IFN-γ stimulation, compared with mock-treated porcine AMs. A gene ontology function enrichment analysis of these DEGs indicated that these genes were significantly enriched in functional clusters such as immune response, defense response, and intracellular signaling cascades. Analyzing the Kyoto Encyclopedia of Genes and Genomes pathways of the DEGs showed that these genes are mainly involved in cytokine-cytokine receptor interactions, alpha linolenic acid metabolism, and the RIG-I-like receptor signaling pathway. This study shows that a massive gene expression change occurred in porcine AMs following IFN-γ stimulation, which is critical for understanding the mechanisms of IFN-γ-mediated macrophage activation and immune regulation.