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Proliferation of actively migrating ameboid microglia in the developing quail retina
J L Marín-Teva1, A Almendros, R Calvente
1Departamento de Biología Celular, Facultad de Ciencias, Universidad de Granada, Spain.
Abstract:
Sheets containing the inner limiting membrane covered by a carpet of Müller cell endfeet were used to show that ameboid microglial cells migrating tangentially in the vitreal part of the developing retina of quail embryos underwent mitosis. Double labeling with anti-beta-tubulin/QH1 or Hoechst 33342/QH1 revealed that some migroglial cells with morphological features typical of active migration were in early prophase. By anaphase and early telophase, microglial cells had retracted their lamellipodia and were ovoid in shape. Later in telophase, but well before completion of cytokinesis, both daughter cells again emitted lamellipodia, thus regaining the typical morphology of migrating cells. We concluded that ameboid microglial cells go through cycles in which migration and mitosis alternate, and that both mechanisms contribute to the spread of microglia throughout the developing retina. The mitotic spindle of dividing microglial cells showed different orientations, which probably influenced the course of subsequent migration. The expression of the proliferating cell nuclear antigen in the nucleus of most tangentially migrating ameboid microglial cells at E9-E10 confirmed their proliferative capability. However, the rate of proliferation of these cells decreased during embryonic development, and was nearly zero at E14.
Insights
Ameboid microglial cells in developing quail retinas divide and migrate, alternating between mitosis and cell movement. This dual mechanism facilitates microglial spread throughout the retina during development.
Area of Science:
- Developmental biology
- Neuroscience
- Cell biology
Background:
- Microglia are crucial immune cells in the central nervous system.
- Their migration and proliferation are essential for retinal development.
- Understanding microglial dynamics is key to studying retinal development and disease.
Purpose of the Study:
- To investigate the cell cycle and migratory behavior of ameboid microglial cells in quail embryos.
- To determine if migrating microglial cells undergo mitosis.
- To elucidate the relationship between microglial migration and proliferation in retinal development.
Main Methods:
- Utilized quail embryo retinal explants with inner limiting membrane and Müller cell endfeet.
- Employed double labeling techniques with anti-beta-tubulin/QH1 and Hoechst 33342/QH1.
- Observed microglial cell morphology and mitotic stages (prophase, anaphase, telophase).
- Assessed proliferating cell nuclear antigen expression.
Main Results:
- Ameboid microglial cells were observed undergoing mitosis while migrating tangentially in the developing retina.
- Migrating microglial cells exhibited morphological changes during cell division, retracting lamellipodia.
- Daughter cells re-established migratory morphology post-mitosis, indicating cyclical behavior.
- Proliferating cell nuclear antigen expression confirmed proliferative capacity in migrating cells.
- Proliferation rate decreased significantly as embryonic development progressed.
Conclusions:
- Ameboid microglial cells alternate between migration and mitosis to spread throughout the developing retina.
- Mitotic spindle orientation may influence subsequent microglial migration patterns.
- Microglial proliferation is a significant contributor to retinal cell population dynamics during development.