Transcriptomic profiling of the development of the inflammatory response in human monocytes in vitro

• Published in: PloS one 2014-02, Vol.9 (2), p.e87680-e87680
• Main Authors: Italiani, Paola, Mazza, Emilia M C, Lucchesi, Davide, Cifola, Ingrid, Gemelli, Claudia, Grande, Alexis, Battaglia, Cristina, Bicciato, Silvio, Boraschi, Diana
• Format: Article
• Language: English
• Subjects: Adult; Biology; Blood & organ donations; Cell Differentiation - genetics; Cells, Cultured; Cellular Microenvironment - genetics; Chemokine CCL5 - genetics; Chemokine CCL5 - metabolism; Cluster Analysis; Councils; Cytokines; DNA microarrays; Enzyme-Linked Immunosorbent Assay; Female; Gene clusters; Gene expression; Gene Expression Profiling; Gene rearrangement; Genes; Homeostasis; Human behavior; Humans; Immune system; Inflammation; Inflammation - genetics; Inflammation - metabolism; Inflammatory response; Interleukin-6 - genetics; Interleukin-6 - metabolism; Interleukin-8 - genetics; Interleukin-8 - metabolism; Life sciences; Macrophages; Macrophages - cytology; Macrophages - metabolism; Male; Metabolism; Middle Aged; Monocytes; Monocytes - cytology; Monocytes - metabolism; Oligonucleotide Array Sequence Analysis; Pathways; Phases; Physiology; Recruitment; Regulatory mechanisms (biology); Reverse Transcriptase Polymerase Chain Reaction; Signal Transduction - genetics; Studies; Transcription factors; Young Adult
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0087680

Monocytes/macrophages are key players in all phases of physiological and pathological inflammation. To understanding the regulation of macrophage functional differentiation during inflammation, we designed an in vitro model that recapitulates the different phases of the reaction (recruitment, initiation, development, and resolution), based on human primary blood monocytes exposed to sequential changes in microenvironmental conditions. All reaction phases were profiled by transcriptomic microarray analysis. Distinct clusters of genes were identified that are differentially regulated through the different phases of inflammation. The gene sets defined by GSEA analysis revealed that the inflammatory phase was enriched in inflammatory pathways, while the resolution phase comprised pathways related to metabolism and gene rearrangement. By comparing gene clusters differentially expressed in monocytes vs. M1 and vs. M2 macrophages extracted from an in-house created meta-database, it was shown that cells in the model resemble M1 during the inflammatory phase and M2 during resolution. The validation of inflammatory and transcriptional factors by qPCR and ELISA confirmed the transcriptomic profiles in the different phases of inflammation. The accurate description of the development of the human inflammatory reaction provided by this in vitro kinetic model can help in identifying regulatory mechanisms in physiological conditions and during pathological derangements.