Related Experiment Video
Updated: Nov 30, 2025
Deciphering and Imaging Pathogenesis and Cording of Mycobacterium abscessus in Zebrafish Embryos
Published on: September 9, 2015
Asap1 Affects the Susceptibility of Zebrafish to Mycobacterium by Regulating Macrophage Migration
Jia Cui1,2, Guangxin Chen1, Da Wen1
1Institutes of Biomedical Sciences, Shanxi University, Taiyuan, China.
Abstract:
The ADP ribosylation factor (ARF) GTPase activation protein ASAP1 possesses multiple biological functions, including regulation of cytoskeletal dynamics, small GTP-binding protein receptor recycling, and intracellular vesicle trafficking. Recently, ASAP1 polymorphisms have been reported to be associated with human susceptibility to tuberculosis (TB) according to a large-scale genome-wide association study (GWAS); ASAP1 expression affects dendritic cell migration, which may be involved in TB predisposition. However, it remains unclear whether ASAP1 affects TB in vivo. To address this issue, we used zebrafish as a model system to examine the effects of Asap1 against Mycobacterium marinum, an organism closely related to Mycobacterium tuberculosis. Two zebrafish asap1 homologs (asap1a and asap1b) were identified and characterized. By morpholino knockdown of asap1a and asap1b as a whole, we found that the asap1 morphants showed a higher mycobacterial load than the controls, which was almost rescued by injecting asap1 mRNA that confers resistance to mycobacterial infection. These Asap1-depleted zebrafish also exhibited decreased macrophage migration in response to tail injury or upon infection with M. marinum in the hindbrain ventricle, which was also proved in THP1-derived macrophages of knockdown ASAP1. Together, these findings represent a new perspective on the role of Asap1 in resistance to mycobacterial infection.
Insights
ADP ribosylation factor (ARF) GTPase activation protein ASAP1 plays a role in resistance to mycobacterial infections. Zebrafish lacking ASAP1 showed increased bacterial load and impaired macrophage migration, suggesting ASAP1 is crucial for host defense.
Area of Science:
- Immunology
- Genetics
- Cell Biology
Background:
- ADP ribosylation factor (ARF) GTPase activation protein ASAP1 is involved in cytoskeletal dynamics and vesicle trafficking.
- ASAP1 gene polymorphisms are linked to tuberculosis susceptibility in humans.
- The in vivo role of ASAP1 in mycobacterial infection resistance is not well understood.
Purpose of the Study:
- To investigate the in vivo function of ASAP1 in resistance to mycobacterial infection using a zebrafish model.
- To characterize the effects of ASAP1 depletion on host defense mechanisms against Mycobacterium marinum.
Main Methods:
- Identified and characterized two zebrafish asap1 homologs (asap1a and asap1b).
- Utilized morpholino knockdown to deplete asap1a and asap1b in zebrafish.
- Assessed mycobacterial load and macrophage migration in asap1-depleted zebrafish.
- Confirmed findings in THP1-derived macrophages with ASAP1 knockdown.
Main Results:
- Zebrafish lacking ASAP1 (asap1 morphants) exhibited a higher mycobacterial load compared to controls.
- ASAP1 mRNA injection partially rescued the increased susceptibility to infection.
- ASAP1 depletion led to decreased macrophage migration in response to injury and M. marinum infection.
- Impaired macrophage migration was also observed in human THP1-derived macrophages with ASAP1 knockdown.
Conclusions:
- ASAP1 plays a significant role in host resistance to mycobacterial infection.
- ASAP1 is essential for proper macrophage migration, a key component of the immune response.
- These findings provide a new perspective on ASAP1's function in innate immunity against mycobacteria.
