Getting everyone to agree on gene signatures for murine macrophage polarization in vitro

PLoS One. 2024 Feb 8;19(2):e0297872. doi: 10.1371/journal.pone.0297872. eCollection 2024.

Abstract

Macrophages, key players in the innate immune system, showcase remarkable adaptability. Derived from monocytes, these phagocytic cells excel in engulfing and digesting pathogens and foreign substances as well as contributing to antigen presentation, initiating and regulating adaptive immunity. Macrophages are highly plastic, and the microenvironment can shaper their phenotype leading to numerous distinct polarized subsets, exemplified by the two ends of the spectrum: M1 (classical activation, inflammatory) and M2 (alternative activation, anti-inflammatory). RNA sequencing (RNA-Seq) has revolutionized molecular biology, offering a comprehensive view of transcriptomes. Unlike microarrays, RNA-Seq detects known and novel transcripts, alternative splicing, and rare transcripts, providing a deeper understanding of genome complexity. Despite the decreasing costs of RNA-Seq, data consolidation remains limited, hindering noise reduction and the identification of authentic signatures. Macrophages polarization is routinely ascertained by qPCR to evaluate those genes known to be characteristic of M1 or M2 skewing. Yet, the choice of these genes is literature- and experience-based, lacking therefore a systematic approach. This manuscript builds on the significant increase in deposited RNA-Seq datasets to determine an unbiased and robust murine M1 and M2 polarization profile. We now provide a consolidated list of global M1 differentially expressed genes (i.e. robustly modulated by IFN-γ, LPS, and LPS+ IFN-γ) as well as consolidated lists of genes modulated by each stimulus (IFN-γ, LPS, LPS+ IFN-γ, and IL-4).

MeSH terms

  • Animals
  • Lipopolysaccharides* / pharmacology
  • Macrophage Activation / genetics
  • Macrophages*
  • Mice
  • Monocytes
  • Phenotype
  • Transcriptome

Substances

  • Lipopolysaccharides

Grants and funding

The research was supported by an AIRC grant to A.A.G. (AIRC IG2018 21842), a PRIN grant from the Italian Ministry of Health to A.A.G. (PRIN 2017 CBNCYT), Telethon grants (GGP19110 and GMR22T1090). An AIRC fellowship to G.C. (Project Code: 25323). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.