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Cytoplasmic motility reflects phagocytic activity in alveolar macrophages from dog lungs
M Yamaya1, T Fukushima, K Sekizawa
1Department of Geriatric Medicine, Tohoku University School of Medicine, Sendai, Japan.
Abstract:
To determine whether cytoplasmic motility relates to phagocytic activity of alveolar macrophages (AM), we measured the remanent field strength (RFS) from the AM containing Fe3O4 particles (5 x 10(6) cells) and the number of phagocytized fluorescent latex spheres in the AM without having Fe3O4 particles (10(6) cells) harvested by broncho-alveolar lavage from dog lungs in vitro. Cytoplasmic motility was estimated from the relaxation rate (lambda o; min-1) calculated from the decay curve of RFS and the number of phagocytized latex spheres was counted using fluorescent microscopy after the addition of latex spheres (5 x 10(7)). The tumor necrosis factor increased both lambda o and the number of phagocytized latex spheres, and cytochalasin D and colchicine decreased them in a concentration-dependent fashion. Increases and decreases in lambda o induced by drugs paralleled the number of phagocytized latex spheres. These results suggest that cytoplasmic motility reflects phagocytic activity of AM and both cytoplasmic movement and phagocytosis may be regulated by a similar mechanism in the cytoskeletal system.
Insights
Cytoplasmic motility in alveolar macrophages (AM) correlates with their phagocytic activity. This suggests a shared regulatory mechanism within the cell's cytoskeleton for both processes.
Area of Science:
- Immunology
- Cell Biology
- Respiratory Medicine
Background:
- Alveolar macrophages (AM) are crucial immune cells in the lungs.
- Understanding factors influencing AM function, like phagocytosis, is vital for respiratory health.
Purpose of the Study:
- To investigate the relationship between cytoplasmic motility and phagocytic activity in AM.
- To explore the potential role of the cytoskeletal system in regulating these functions.
Main Methods:
- Alveolar macrophages were harvested from dog lungs in vitro.
- Cytoplasmic motility was assessed by measuring remanent field strength (RFS) changes.
- Phagocytic activity was quantified by counting internalized fluorescent latex spheres.
Main Results:
- Tumor necrosis factor increased both cytoplasmic motility (lambda o) and phagocytosis.
- Cytochalasin D and colchicine reduced both motility and phagocytosis in a dose-dependent manner.
- Changes in cytoplasmic motility directly paralleled changes in phagocytic activity.
Conclusions:
- Cytoplasmic motility serves as a reliable indicator of alveolar macrophage phagocytic activity.
- Both cytoplasmic movement and phagocytosis in AM appear to be regulated by common cytoskeletal mechanisms.