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.

Microbes living in the polar regions have some common and unique strategies to respond to thermal stress. Nevertheless, the amount of information available, especially at the molecular level is lacking for some organisms such as Antarctic psychrophilic yeast. For instance, it is not known whether molecular chaperones in Antarctic yeasts play similar roles to those from mesophilic yeasts when they are exposed to heat stress. Therefore, this project aimed to determine the gene expression patterns and roles of molecular chaperones in Antarctic psychrophilic Glaciozyma antarctica PI12 that was exposed to heat stress. G. antarctica PI12 was grown at its optimal growth temperature of 12ºC and later exposed to heat stresses at 16ºC and 20ºC for 6 hours. Transcriptomes of those cells were extracted, sequenced and analyzed. Thirty-three molecular chaperone genes demonstrated differential expression of which 23 were up-regulated while 10 were down-regulated. Functions of up-regulated molecular chaperone genes were related to protein binding, response to a stimulus, chaperone binding, cellular response to stress, oxidation, and reduction, ATP binding, DNA-damage response and regulation for cellular protein metabolic process. On the other hand, functions of down-regulated molecular chaperone genes were related to chaperone-mediated protein complex assembly, transcription, cellular macromolecule metabolic process, regulation of cell growth and ribosome biogenesis. The findings provided information on how molecular chaperones work together in a complex network to protect the cells under heat stress. It also highlights the evolutionary conserved protective role of molecular chaperones in psychrophilic yeast, G. antarctica, and mesophilic yeast, Saccharomyces cerevisiae.