Related Experiment Video
Updated: Jan 13, 2026
Proteomic Analysis of Human Macrophage Polarization Under a Low Oxygen Environment
Published on: January 7, 2019
The proteomic landscape of blood monocytes in community-acquired pneumonia
Osoul Chouchane1, Erik H A Michels1, Giuseppe G F Leite2
1Centre for Infection and Molecular Medicine (CIMM), Amsterdam University Medical Centre, University of Amsterdam, Amsterdam, The Netherlands.
Introduction:
Monocytes play a pivotal role in the regulation of inflammation and pathogen clearance during infection. Knowledge of the human monocyte proteome during infection is limited. We present a comprehensive proteome profile of blood monocytes from patients with community-acquired pneumonia (CAP), one of the most common infectious diseases, and controls without infection.
Methods:
Monocytes were purified from blood of patients with CAP within 16 h of admission to a general hospital ward and from controls matched for sex, age and comorbidities. Monocyte proteins were measured using liquid chromatography/mass spectrometry. The transcriptome was analysed in the same samples by RNA sequencing. Monocytes were stimulated with lipopolysaccharide for 24 h, after which cytokines were measured in the supernatant.
Results:
We analysed the monocyte proteome of 34 CAP patients and 23 controls. Out of 7315 annotated proteins, 1340 (18.3%) were differentially abundant between groups. Functional enrichment analyses revealed a marked downregulation of mitochondrial respiration processes in patient monocytes; pathways pertaining to cell cycle, cytokine signalling and cell death were upregulated in patient monocytes. Monocyte mRNA levels correlated poorly with the abundance of corresponding proteins and associated functional pathways, raising caution regarding interpretation of functionality estimates based on transcriptome analyses. Differential expression of monocyte proteins had functional and clinical implications as indicated by associations with cytokine production capacity, disease severity and time to clinical stability.
Conclusion:
This study provides a publicly available monocyte protein atlas that can serve as a resource for future research on monocyte functions during infection.
Insights
This study reveals significant protein changes in monocytes from community-acquired pneumonia (CAP) patients, highlighting altered mitochondrial function and cell signaling pathways. This proteomic data offers insights into monocyte roles during infection.
Area of Science:
- Immunology
- Proteomics
- Infectious Diseases
Background:
- Monocytes are crucial for inflammation and pathogen clearance.
- Limited understanding of the human monocyte proteome during infection.
- Community-acquired pneumonia (CAP) is a common infectious disease.
Purpose of the Study:
- To comprehensively profile the blood monocyte proteome in CAP patients versus controls.
- To investigate functional and clinical implications of monocyte protein alterations in CAP.
Main Methods:
- Purification of monocytes from CAP patients and matched controls.
- Proteomic analysis using liquid chromatography/mass spectrometry.
- Transcriptome analysis via RNA sequencing and cytokine measurements after stimulation.
Main Results:
- Identified 1340 differentially abundant proteins in CAP patient monocytes out of 7315 annotated.
- Observed downregulation of mitochondrial respiration and upregulation of cell cycle/cytokine signaling pathways.
- Found poor correlation between mRNA and protein levels, impacting transcriptome-based functional estimates.
Conclusions:
- Presents a comprehensive monocyte protein atlas for CAP.
- Highlights functional and clinical relevance of monocyte protein changes in CAP.
- Provides a resource for future research on monocyte function in infection.
