Related Experiment Video
Updated: Jun 11, 2026
Polarization of M1 and M2 Human Monocyte-Derived Cells and Analysis with Flow Cytometry upon Mycobacterium tuberculosis Infection
Published on: September 18, 2020
Physiologic medium renders human iPSC-derived macrophages permissive for M. tuberculosis by rewiring organelle
Claudio Bussi1,2, Rachel Lai1,3, Natalia Athanasiadi1
1The Francis Crick Institute, London, United Kingdom.
Abstract:
In vitro studies are crucial for our understanding of the human macrophage immune functions. However, traditional in vitro culture media poorly reflect the metabolic composition of blood, potentially affecting the outcomes of these studies. Here, we analyzed the impact of a physiological medium on human induced pluripotent stem cell (iPSC)-derived macrophages (iPSDM) function. Macrophages cultured in a human plasma-like medium (HPLM) were more permissive to Mycobacterium tuberculosis (Mtb) replication and showed decreased lipid metabolism with increased metabolic polarization. Functionally, we discovered that HPLM-differentiated macrophages showed different metabolic organelle content and activity. Specifically, HPLM-differentiated macrophages displayed reduced lipid droplet and peroxisome content, increased lysosomal proteolytic activity, and increased mitochondrial activity and dynamics. Inhibiting or inducing lipid droplet formation revealed that lipid droplet content is a key factor influencing macrophage permissiveness to Mtb. These findings underscore the importance of using physiologically relevant media in vitro for accurately studying human macrophage function.
Importance:
This work compellingly demonstrates that the choice of culture medium significantly influences M. tuberculosis replication outcomes, thus emphasizing the importance of employing physiologically relevant media for accurate in vitro host-pathogen interaction studies. We anticipate that our work will set a precedent for future research with clinical relevance, particularly in evaluating antibiotic efficacy and resistance in cellulo.
Insights
Using a human plasma-like medium for macrophage cultures alters their function and increases Mycobacterium tuberculosis replication. This highlights the need for physiologically relevant media in vitro for accurate immune studies.
Area of Science:
- Immunology
- Cell Biology
- Microbiology
Background:
- In vitro studies are vital for understanding human macrophage immune functions.
- Traditional culture media do not accurately mimic blood's metabolic composition, potentially skewing experimental results.
- Human induced pluripotent stem cell-derived macrophages (iPSDM) are a key model for studying macrophage behavior.
Purpose of the Study:
- To investigate the impact of a physiological medium on human iPSC-derived macrophage function.
- To determine how a human plasma-like medium (HPLM) affects Mycobacterium tuberculosis (Mtb) replication.
- To elucidate the metabolic and functional changes in macrophages cultured in HPLM.
Main Methods:
- Culturing iPSDM in either traditional medium or HPLM.
- Assessing Mtb replication rates in HPLM-cultured macrophages.
- Analyzing macrophage metabolic organelle content and activity (lipid droplets, peroxisomes, lysosomes, mitochondria).
- Manipulating lipid droplet formation to assess its role in Mtb permissiveness.
Main Results:
- Macrophages cultured in HPLM showed increased Mtb replication.
- HPLM-cultured macrophages exhibited decreased lipid metabolism and increased metabolic polarization.
- Significant alterations in organelle content and activity were observed, including reduced lipid droplets and peroxisomes, and increased lysosomal and mitochondrial activity.
- Lipid droplet content was identified as a critical factor influencing macrophage permissiveness to Mtb.
Conclusions:
- The choice of culture medium significantly impacts in vitro macrophage function and host-pathogen interactions.
- Physiologically relevant media are essential for accurate in vitro studies of human macrophage immunity.
- This research sets a precedent for using relevant media in host-pathogen studies, with implications for evaluating antibiotic efficacy.
More Related Videos
09:34An Automated Culture System for Use in Preclinical Testing of Host-Directed Therapies for Tuberculosis
Published on: August 16, 2021
06:26Author Spotlight: Optimizing CFU Determination for Efficient Assessment of TB Vaccine Efficacy and Antigen Presentation Analysis
Published on: July 28, 2023
