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Updated: Apr 1, 2026
Author Spotlight: Using Zebrafish to Explore Microglia Migration During Brain Development
Published on: May 17, 2024
Temporal-Spatial Resolution Fate Mapping Reveals Distinct Origins for Embryonic and Adult Microglia in Zebrafish
1Division of Life Science, State Key Laboratory of Molecular Neuroscience, Center of Systems Biology and Human Health, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, PRC.
Abstract:
Microglia are CNS resident macrophages, and they play important roles in neural development and function. Recent studies have suggested that murine microglia arise from a single source, the yolk sac (YS), yet these studies lack spatial resolution to define the bona fide source(s) for microglia. Here, using light-induced high temporal-spatial resolution fate mapping, we challenge this single-source view by showing that microglia in zebrafish arise from multiple sources. The embryonic/larval microglia originate from the rostral blood island (RBI) region, the equivalent of mouse YS for myelopoiesis, whereas the adult microglia arise from the ventral wall of dorsal aorta (VDA) region, a tissue also producing definitive hematopoiesis in mouse. We further show that the VDA-region-derived microglia are Runx1 dependent, but cMyb independent, and developmentally regulated differently from the RBI region-derived microglia. Our study establishes a new paradigm for investigating the development and function of distinct microglia populations.
Insights
Zebrafish microglia originate from multiple sources, challenging the single yolk sac origin. Embryonic microglia arise from the rostral blood island, while adult microglia derive from the ventral aorta, revealing distinct developmental pathways.
Area of Science:
- Neuroscience
- Developmental Biology
- Immunology
Background:
- Microglia, the resident macrophages of the central nervous system (CNS), are crucial for neural development and function.
- Previous research suggested a single origin for murine microglia from the yolk sac (YS), but lacked the resolution to confirm this definitively.
Purpose of the Study:
- To investigate the origins of microglia in zebrafish using high temporal-spatial resolution fate mapping.
- To challenge the prevailing single-source hypothesis for microglia development.
Main Methods:
- Utilized light-induced fate mapping in zebrafish to achieve high temporal and spatial resolution.
- Analyzed the origins of both embryonic/larval and adult microglia populations.
Main Results:
- Demonstrated that zebrafish microglia originate from multiple sources, not a single yolk sac equivalent.
- Identified the rostral blood island (RBI) as the source for embryonic/larval microglia.
- Identified the ventral wall of the dorsal aorta (VDA) as the source for adult microglia, a site of definitive hematopoiesis.
- Showed VDA-derived microglia are Runx1 dependent but cMyb independent, with distinct developmental regulation compared to RBI-derived microglia.
Conclusions:
- Established a new paradigm for understanding microglia development, highlighting multiple origins and distinct populations.
- The findings in zebrafish provide a new model for investigating the diverse roles of microglia in CNS health and disease.
