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Isolation of Murine Peritoneal Macrophages to Carry Out Gene Expression Analysis Upon Toll-like Receptors Stimulation
Published on: April 29, 2015
Protection of macrophages from intracellular pathogens by miR-182-5p mimic-a gene expression meta-analysis approach
David J Gregory1, Igor Kramnik2, Lester Kobzik1
1Molecular and Physiological Sciences Program, Department of Environmental Health, Harvard T.H. Chan School of Public Health, Boston, MA, USA.
Abstract:
The goals of this study were to (a) define which host genes are of particular importance during the interactions between macrophages and intracellular pathogens, and (b) use this knowledge to gain fresh, experimental understanding of how macrophage activities may be manipulated during host defense. We designed an in silico method for meta-analysis of microarray gene expression data, and used this to combine data from 16 different studies of cells in the monocyte-macrophage lineage infected with seven different pathogens. Three thousand four hundred ninety-eight genes were identified, which we call the macrophage intracellular pathogen response (macIPR) gene set. As expected, the macIPR gene set showed a strong bias toward genes previously associated with the immune response. Predicted target sites for miR-182-5p (miR-182) were strongly over-represented among macIPR genes, indicating an unexpected role for miR-182-regulatable genes during intracellular pathogenesis. We therefore transfected primary human alveolar macrophage-like monocyte-derived macrophages from multiple different donors with synthetic miR-182, and found that miR-182 overexpression (a) increases proinflammatory gene induction during infection with Francisella tularensis live vaccine strain (LVS), (b) primes macrophages for increased autophagy, and (c) enhances macrophage control of both gram negative F. tularensisLVS and gram positive Bacillus anthracisANR-1 spores. These data therefore suggest a new application for miR-182 in promoting resistance to intracellular pathogens.
Insights
Researchers identified key host genes involved in macrophage responses to intracellular pathogens. They discovered that miR-182 enhances macrophage defense against bacteria like Francisella tularensis and Bacillus anthracis, suggesting a new therapeutic strategy.
Area of Science:
- Immunology
- Microbiology
- Genetics
Background:
- Macrophages are crucial immune cells that phagocytose and eliminate intracellular pathogens.
- Understanding host gene regulation during macrophage-pathogen interactions is vital for host defense.
- MicroRNAs (miRNAs) play significant roles in modulating immune responses.
Purpose of the Study:
- To identify host genes critical for macrophage interactions with intracellular pathogens.
- To investigate the role of miR-182 in macrophage-pathogen dynamics.
- To explore the potential of manipulating macrophage activity for enhanced host defense.
Main Methods:
- In silico meta-analysis of 16 microarray gene expression datasets from infected monocyte-macrophage lineage cells.
- Identification of the macrophage intracellular pathogen response (macIPR) gene set.
- Experimental validation using primary human alveolar macrophages transfected with synthetic miR-182 and infected with Francisella tularensis LVS and Bacillus anthracis ANR-1.
Main Results:
- A set of 3,498 macrophage intracellular pathogen response (macIPR) genes was identified, enriched for immune response genes.
- miR-182 target sites were over-represented in macIPR genes, suggesting a novel role for miR-182.
- miR-182 overexpression enhanced pro-inflammatory gene induction, primed macrophages for autophagy, and improved control of Francisella tularensis and Bacillus anthracis.
Conclusions:
- miR-182 plays a significant role in modulating macrophage responses to intracellular bacterial pathogens.
- miR-182 enhances macrophage effector functions, including inflammation, autophagy, and pathogen clearance.
- miR-182 represents a potential therapeutic target for boosting host resistance against intracellular pathogens.
