Translational Regulation of Specific mRNAs Controls Feedback Inhibition and Survival During Macrophage Activation

PLoS Genet. 2014 Jun 19;10(6):e1004368. doi: 10.1371/journal.pgen.1004368. eCollection 2014 Jun.

Abstract

For a rapid induction and efficient resolution of the inflammatory response, gene expression in cells of the immune system is tightly regulated at the transcriptional and post-transcriptional level. The control of mRNA translation has emerged as an important determinant of protein levels, yet its role in macrophage activation is not well understood. We systematically analyzed the contribution of translational regulation to the early phase of the macrophage response by polysome fractionation from mouse macrophages stimulated with lipopolysaccharide (LPS). Individual mRNAs whose translation is specifically regulated during macrophage activation were identified by microarray analysis. Stimulation with LPS for 1 h caused translational activation of many feedback inhibitors of the inflammatory response including NF-κB inhibitors (Nfkbid, Nfkbiz, Nr4a1, Ier3), a p38 MAPK antagonist (Dusp1) and post-transcriptional suppressors of cytokine expression (Zfp36 and Zc3h12a). Our analysis showed that their translation is repressed in resting and de-repressed in activated macrophages. Quantification of mRNA levels at a high temporal resolution by RNASeq allowed us to define groups with different expression patterns. Thereby, we were able to distinguish mRNAs whose translation is actively regulated from mRNAs whose polysomal shifts are due to changes in mRNA levels. Active up-regulation of translation was associated with a higher content in AU-rich elements (AREs). For one example, Ier3 mRNA, we show that repression in resting cells as well as de-repression after stimulation depends on the ARE. Bone-marrow derived macrophages from Ier3 knockout mice showed reduced survival upon activation, indicating that IER3 induction protects macrophages from LPS-induced cell death. Taken together, our analysis reveals that translational control during macrophage activation is important for cellular survival as well as the expression of anti-inflammatory feedback inhibitors that promote the resolution of inflammation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adaptor Proteins, Signal Transducing / biosynthesis
  • Adaptor Proteins, Signal Transducing / genetics
  • Animals
  • Base Sequence
  • Cell Line
  • Cytokines / antagonists & inhibitors
  • Cytokines / genetics*
  • Dual Specificity Phosphatase 1 / biosynthesis
  • Dual Specificity Phosphatase 1 / genetics
  • Gene Expression Regulation / genetics
  • HEK293 Cells
  • Humans
  • Immediate-Early Proteins / genetics*
  • Lipopolysaccharides
  • Macrophage Activation / genetics*
  • Macrophage Activation / immunology
  • Macrophages / immunology*
  • Mice
  • Mice, Knockout
  • NF-kappa B / antagonists & inhibitors
  • Nuclear Proteins / biosynthesis
  • Nuclear Proteins / genetics
  • Nuclear Receptor Subfamily 4, Group A, Member 1 / biosynthesis
  • Nuclear Receptor Subfamily 4, Group A, Member 1 / genetics
  • Protein Biosynthesis / genetics
  • RNA, Messenger / genetics*
  • Ribonucleases / biosynthesis
  • Ribonucleases / genetics
  • Sequence Analysis, RNA
  • Tristetraprolin / biosynthesis
  • Tristetraprolin / genetics
  • p38 Mitogen-Activated Protein Kinases / antagonists & inhibitors

Substances

  • Adaptor Proteins, Signal Transducing
  • Cytokines
  • IEX-1 protein, mouse
  • Immediate-Early Proteins
  • Lipopolysaccharides
  • NF-kappa B
  • Nfkbiz protein, mouse
  • Nr4a1 protein, mouse
  • Nuclear Proteins
  • Nuclear Receptor Subfamily 4, Group A, Member 1
  • RNA, Messenger
  • Tristetraprolin
  • Zfp36 protein, mouse
  • p38 Mitogen-Activated Protein Kinases
  • Ribonucleases
  • Zc3h12a protein, mouse
  • Dual Specificity Phosphatase 1
  • Dusp1 protein, mouse

Grant support

This work was supported by research grants STO 859/2-1 and SFB 1036/TP07 from the Deutsche Forschungsgemeinschaft (http://www.dfg.de/en/) to GS, and family support funds from the Schlieben-Lange Program (http://mwk.baden-wuerttemberg.de/hochschulen/foerderung-von-wissenschaftlerinnen-und-wissenschaftlern/frauenfoerderung/brigitte-schlieben-lange-programm/) and the Hartmut Hoffmann-Berling International Graduate School of Molecular and Cellular Biology (http://www.hbigs.uni-heidelberg.de/) to JS. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.