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Updated: Nov 8, 2025
Assessing the Age-Specific Phagocytic Ability of Adult Drosophila melanogaster Hemocytes using an In Vivo Phagocytosis Assay
Published on: June 11, 2020
Identification of functionally distinct macrophage subpopulations in Drosophila
Jonathon Alexis Coates1, Elliot Brooks2, Amy Louise Brittle2
1Department of Biomedical Science and the Bateson Centre, University of Sheffield, Sheffield, United Kingdom.
Abstract:
Vertebrate macrophages are a highly heterogeneous cell population, but while Drosophila blood is dominated by a macrophage-like lineage (plasmatocytes), until very recently these cells were considered to represent a homogeneous population. Here, we present our identification of enhancer elements labelling plasmatocyte subpopulations, which vary in abundance across development. These subpopulations exhibit functional differences compared to the overall population, including more potent injury responses and differential localisation and dynamics in pupae and adults. Our enhancer analysis identified candidate genes regulating plasmatocyte behaviour: pan-plasmatocyte expression of one such gene (Calnexin14D) improves wound responses, causing the overall population to resemble more closely the subpopulation marked by the Calnexin14D-associated enhancer. Finally, we show that exposure to increased levels of apoptotic cell death modulates subpopulation cell numbers. Taken together this demonstrates macrophage heterogeneity in Drosophila, identifies mechanisms involved in subpopulation specification and function and facilitates the use of Drosophila to study macrophage heterogeneity in vivo.
Insights
Drosophila plasmatocytes, the fly equivalent of macrophages, are not a uniform cell type. Researchers identified distinct subpopulations with unique functions, revealing mechanisms of cell specification and regulation.
Area of Science:
- Developmental Biology
- Immunology
- Genetics
Background:
- Vertebrate macrophages are known for their heterogeneity, but Drosophila plasmatocytes were recently considered a homogeneous population.
- Understanding immune cell diversity is crucial for comprehending host defense and development.
Purpose of the Study:
- To identify and characterize distinct plasmatocyte subpopulations in Drosophila.
- To investigate the functional differences and regulatory mechanisms underlying plasmatocyte heterogeneity.
- To establish Drosophila as a model for studying macrophage heterogeneity in vivo.
Main Methods:
- Identification of enhancer elements to label specific plasmatocyte subpopulations.
- Analysis of subpopulation abundance, localization, and dynamics during development.
- Functional assays to assess injury responses and gene expression (e.g., Calnexin14D).
- Investigation of the impact of apoptotic cell death on subpopulation numbers.
Main Results:
- Discovery of enhancer elements that label distinct plasmatocyte subpopulations with varying developmental abundance.
- Demonstration of functional differences, including enhanced injury responses in specific subpopulations.
- Identification of Calnexin14D as a gene regulating plasmatocyte behavior and improving wound responses.
- Evidence that increased apoptotic cell death modulates subpopulation cell numbers.
Conclusions:
- Drosophila plasmatocytes exhibit heterogeneity, challenging previous assumptions of homogeneity.
- Mechanisms for subpopulation specification and function have been identified, including the role of Calnexin14D.
- The study validates Drosophila as a powerful in vivo model for studying complex macrophage heterogeneity.
