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5-Azacytidine (5Az) induces apoptosis in PC12 cells: a model for 5Az-induced apoptosis in developing neuronal cells
M M Hossain1, H Nakayama, A Takashima
1Department of Veterinary Pathology, Faculty of Agriculture, University of Tokyo, Japan.
Abstract:
Our previous in vivo and in vitro studies showed that 5-azacytidine (5Az), a cytidine analog, induced apoptosis in developing neuronal cells in mice. To develop a system in which the precise molecular mechanism of 5Az-induced apoptosis in developing neuronal cells could be elucidated, we carried out the present study with PC12 cells. These cells are derived from a rat pheochromocytoma and extrude neurites in response to nerve growth factor (NGF). Light microscopy showed dose-dependent pyknotic and karyorrhectic changes in undifferentiated PC12 cells. Although they were less sensitive to 5Az, NGF-treated differentiated cells showed the same changes. Analysis by the TUNEL method (an in situ method for the detection of apoptosis) showed positive signals in the pyknotic and fragmented nuclei of these cells. Transmission electron microscopy revealed margination, segmentation, and condensation of nuclear chromatin, cell body shrinkage, and cytoplasmic vacuolization. Scanning electron microscopy demonstrated bleb formation on the cell surface. These pathomorphological changes are typical of apoptosis. 5Az seemed to affect cells that were in the proliferative stage; when the cells were terminally differentiated, their sensitivity to 5Az appeared to decline. PC12 cells could be used as a pathomorphological and biochemical model for studies of 5Az-induced neuronal cell apoptosis at the molecular and genetic level.
Insights
5-azacytidine (5Az) induces apoptosis in developing neuronal cells. PC12 cells, a rat pheochromocytoma model, exhibit typical apoptotic changes, making them suitable for studying 5Az
Area of Science:
- Neuroscience
- Molecular Biology
- Cell Biology
Background:
- 5-azacytidine (5Az), a cytidine analog, has demonstrated apoptosis-inducing effects in developing neuronal cells.
- Understanding the precise molecular mechanisms of 5Az-induced apoptosis is crucial for neurodevelopmental research.
Purpose of the Study:
- To establish a PC12 cell system for elucidating the molecular mechanisms of 5-azacytidine-induced apoptosis in developing neuronal cells.
- To investigate the pathomorphological changes associated with 5Az exposure in PC12 cells.
Main Methods:
- PC12 cells, derived from rat pheochromocytoma, were treated with varying doses of 5-azacytidine (5Az).
- Light microscopy, TUNEL assay, transmission electron microscopy (TEM), and scanning electron microscopy (SEM) were employed to analyze cellular changes.
- Cells were studied in both undifferentiated and nerve growth factor (NGF)-treated differentiated states.
Main Results:
- 5Az induced dose-dependent pyknotic and karyorrhectic changes, indicative of apoptosis, in undifferentiated PC12 cells.
- NGF-treated differentiated PC12 cells showed similar apoptotic changes, though with reduced sensitivity to 5Az.
- Microscopic analyses confirmed typical apoptotic features, including nuclear chromatin condensation, cell shrinkage, cytoplasmic vacuolization, and bleb formation.
Conclusions:
- PC12 cells serve as a viable pathomorphological and biochemical model for studying 5Az-induced neuronal cell apoptosis.
- 5Az primarily affects proliferating neuronal cells, with sensitivity decreasing upon terminal differentiation.
- This model facilitates molecular and genetic investigations into the mechanisms underlying 5Az-induced neuroapoptosis.