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Updated: Jun 26, 2026
Flow Cytometric Analysis for Identification of the Innate and Adaptive Immune Cells of Murine Lung
Published on: November 16, 2021
Transcriptome profiling of primary murine monocytes, lung macrophages and lung dendritic cells reveals a distinct
Zbigniew Zasłona1, Jochen Wilhelm, Lidija Cakarova
1Department of Internal Medicine, Division of Pulmonary and Critical Care Medicine, University of Giessen Lung Center, Giessen, Germany. zbigniew.zaslona@innere.med.uni-giessen.de
Background:
Peripheral blood monocytes (PBMo) originate from the bone marrow, circulate in the blood and emigrate into various organs where they differentiate into tissue resident cellular phenotypes of the mononuclear phagocyte system, including macrophages (Mphi) and dendritic cells (DC). Like in other organs, this emigration and differentiation process is essential to replenish the mononuclear phagocyte pool in the lung under both inflammatory and non-inflammatory steady-state conditions. While many studies have addressed inflammation-driven monocyte trafficking to the lung, the emigration and pulmonary differentiation of PBMo under non-inflammatory conditions is much less understood.
Methods:
In order to assess the transcriptional profile of circulating and lung resident mononuclear phagocyte phenotypes, PBMo, lung Mphi and lung DC from naïve mice were flow-sorted to high purity, and their gene expression was compared by DNA microarrays on a genome-wide scale. Differential regulation of selected genes was validated by quantitative PCR and on protein level by flow cytometry.
Results:
Differentially-expressed genes related to cell traffic were selected and grouped into the clusters (i) matrix metallopeptidases, (ii) chemokines/chemokine receptors, and (iii) integrins. Expression profiles of clustered genes were further assessed at the mRNA and protein levels in subsets of circulating PBMo (GR1- vs GR1+) and lung resident macrophages (alveolar vs interstitial Mphi). Our data identify differentially activated genetic programs in circulating monocytes and their lung descendents. Lung DC activate an extremely diverse set of gene families but largely preserve a mobile cell profile with high expression levels of integrin and chemokine/chemokine receptors. In contrast, interstitial and even more pronounced alveolar Mphi, stepwise downregulate gene expression of these traffic relevant communication molecules, but strongly upregulate a distinct set of matrix metallopetidases potentially involved in tissue invasion and remodeling.
Conclusion:
Our data provide new insight in the changes of the genetic profiles of PBMo and their lung descendents, namely DC and Mphi under non-inflammatory, steady-state conditions. These findings will help to better understand the complex relations within the mononuclear phagocyte pool of the lung.
Insights
Peripheral blood monocytes (PBMo) differentiate into lung macrophages and dendritic cells. Under non-inflammatory conditions, lung cells alter gene expression for tissue remodeling and cell trafficking.
Area of Science:
- Immunology
- Cell Biology
- Genomics
Background:
- Peripheral blood monocytes (PBMo) are crucial for replenishing lung immune cells.
- Monocyte emigration and differentiation in the lung are vital for homeostasis.
- Non-inflammatory PBMo lung trafficking and differentiation are poorly understood.
Purpose of the Study:
- To investigate the transcriptional profiles of circulating monocytes and their lung-resident progeny.
- To understand gene expression changes in lung mononuclear phagocytes under non-inflammatory conditions.
Main Methods:
- Flow-sorted PBMo, lung macrophages, and lung dendritic cells from naïve mice were analyzed.
- Genome-wide gene expression was compared using DNA microarrays.
- Differential gene expression was validated by quantitative PCR and flow cytometry.
Main Results:
- Circulating monocytes and their lung descendants exhibit distinct transcriptional profiles.
- Lung dendritic cells maintain a mobile cell phenotype with high integrin and chemokine receptor expression.
- Lung macrophages downregulate trafficking molecules and upregulate matrix metalloproteinases for tissue remodeling.
Conclusions:
- Provides novel insights into the genetic profiles of PBMo and their lung descendants (DC, Mphi) in non-inflammatory states.
- Enhances understanding of the mononuclear phagocyte system dynamics within the lung.
