Differential Responsiveness of Monocyte and Macrophage Subsets to Interferon

Abstract

Objective Peripheral blood mononuclear cells (PBMCs) in systemic lupus erythematosus (SLE) patients exhibit a gene expression program (interferon [IFN] signature) that is attributed to overproduction of type I IFNs by plasmacytoid dendritic cells. Type I IFNs have been thought to play a role in the pathogenesis of SLE. This study was undertaken to examine an unexpected influence of monocyte/macrophages on the IFN signature. Methods Proinflammatory (classic) and antiinflammatory (nonclassic) monocyte/macrophages were sorted from mice and analyzed by RNA sequencing and quantitative polymerase chain reaction (qPCR). Type I IFN‐α/β/ω receptor (IFNAR‐1) expression was determined by qPCR and flow cytometry. Macrophages were stimulated in vitro with IFNα, and pSTAT1was measured. Results Transcriptional profiling of peritoneal macrophages from mice with pristane‐induced SLE unexpectedly indicated a strong IFN signature in classic, but not nonclassic, monocyte/macrophages exposed to the same type I IFN concentrations. Ifnar1 messenger RNA and IFNAR surface staining were higher in classic monocyte/macrophages versus nonclassic monocyte/macrophages (P < 0.0001 and P < 0.05, respectively, by Student's t‐test). Nonclassic monocyte/macrophages were also relatively insensitive to IFNα‐driven STAT1 phosphorylation. Humans exhibited a similar pattern: higher IFNAR expression (P < 0.0001 by Student's t‐test) and IFNα‐stimulated gene expression (P < 0.01 by paired Wilcoxon's rank sum test) in classic monocyte/macrophages and lower levels in nonclassic monocyte/macrophages. Conclusion This study revealed that the relative abundance of different monocyte/macrophage subsets helps determine the magnitude of the IFN signature. Responsiveness to IFNα signaling reflects differences in IFNAR expression in classic (high IFNAR) compared to nonclassic (low IFNAR) monocyte/macrophages. Thus, the IFN signature depends on both type I IFN production and the responsiveness of monocyte/macrophages to IFNAR signaling.

NF‐E2–Related Factor 2 Regulates Interferon Receptor Expression and Alters Macrophage Polarization in Lupus

“…RNA sequencing (RNA‐Seq) was performed at Broad Institute using the Smart‐seq2 platform as previously described . Gene set enrichment analysis (GSEA) was performed using Broad Institute GSEA Desktop software version 2.2.4 and hallmark gene sets from the Molecular Signature Database, version 6.2 . The RNA‐Seq data discussed in this publication are available from the corresponding author upon request.…”

“…C57BL/6 (B6), B6.129X1‐Nfe2l2 tm1Ywk /J (B6 Nrf2‐knockout), and B6.129S2‐Ifnar1 tm1Agt /Mmjax (B6 IFNAR‐knockout [IFNAR‐KO]) mice (The Jackson Laboratory) maintained under specific pathogen–free conditions were injected intraperitoneally (IP) with 0.5 ml of pristane or mineral oil as previously described . There were 5–15 mice per group unless otherwise noted.…”

“…Quantitative PCR was performed as previously described using RNA isolated from 10 6 mouse peritoneal exudate cells or from human blood collected in PAXgene tubes. Gene expression was normalized to 18S ribosomal RNA (18S rRNA), and expression was calculated using the 2 –ΔΔCt method.…”

“…Classic macrophages (CMs) are more responsive to type I IFN than NCMs . The ability of monocyte/macrophages to respond to type I IFN signaling correlates with IFNAR expression, but the mechanism(s) regulating IFNAR expression are unclear.…”

Transcriptomic Analyses for Identification and Prioritization of Genes Associated With Alzheimer’s Disease in Humans

“…Wilcoxon rank sum test was used to identify the differentially expressed lncRNAs and PCGs between the AD cases and the control group with the threshold of P < 0.01 (Han et al, 2019). Classification of lncRNAs and PCGs was according to the gene annotation file derived from GENCODE.…”