Effect of chronic type I IFN exposure on the transcriptional, metabolic profiles of human monocyte-derived macrophages

The impact of chronic exposure to type I interferons (IFN)α2a,2b, and β, on macrophage metabolism, intimately linked to macrophage function, is not well understood. This study assesses the nuanced host responses induced by type I IFN cytokines, offering insights for potential therapeutic approaches in diseases associated with these cytokines. Employing a combination of transcriptional profiling and real-time functional analysis, we delineated the temporal evolution of metabolic reprogramming in response to chronic interferon exposure. Our results reveal distinct transcriptional metabolic profiles between macrophages chronically exposed to IFNα and IFNβ. IFNβ significantly diminishes the oxygen consumption rate and glycolytic proton extrusion rate in macrophages. Conversely, IFNα2b decreased parameters of mitochondrial fitness and induced a shift towards glutamine oxidation. Assessing the ability of macrophages to induce glycolysis in response to antigenic stimuli (LPS and iH37Rv), we found that chronic exposure to all IFN subtypes limited glycolytic induction. This study addresses a critical oversight in the literature, where individual roles of IFN subtypes are frequently amalgamated and lack distinction. These findings not only provide novel insights into the divergent effects of interferon α2a,α2b, and β on macrophage metabolism but also highlight their potential implications for developing targeted therapeutic strategies. Peripheral blood mononuclear cells (PBMC) were isolated from the buffy coats of healthy donors by density-gradient centrifugation over Lymphoprep (StemCell Technologies). Cells were washed, resuspended at 2.5x106 PBMC/ml in RPMI (Gibco) supplemented with 10% AB human serum (Sigma90 Aldrich), and plated onto non-treated tissue culture plates (Costar). Cells were maintained in humidified incubators for 7 days at 37°C and 5% CO2. Human IFNβ (IF014, Merck, KGaA, Darmstadt), IFNα2a (11100-1, PBL assay science, NJ, USA), and IFN IFNα2b (11105-1, PBL assay science, NJ, USA) were added at a concentration of 1000U/ml for 5 day before analysis. On day 5 of chronic type I IFN exposure, RNA from each treatment group was extracted using the RNeasy® Plus Mini Kit (Qiagen, Limburg, Netherlands). The NanoString nCounter Human Metabolic Pathways Panel (Cat # XT-CSO-HMP1-12, N = 6 per IFN subtype; transcripts of 768 metabolic genes) was used to generate gene expression data.