Related Experiment Videos
Multiple pathways of apoptosis in PC12 cells. CrmA inhibits apoptosis induced by beta-amyloid
K J Ivins1, J K Ivins, J P Sharp
1Institute for Brain Aging and Dementia, University of California at Irvine, Irvine, California 92697, USA. kjivins@uci.edu
Abstract:
Stable transfectants of PC12 cells expressing bcl-2 or crmA were generated and tested for their susceptibility to various apoptotic insults. Bcl-2 expression conferred resistance to apoptosis induced by staurosporine and by oxidative insults including hydrogen peroxide and peroxynitrite, but was less effective in inhibition of activation-induced programmed cell death induced by concanavalin A. Concanavalin A-induced apoptosis was abated, however, in cells expressing very high levels of bcl-2. In contrast, cells expressing crmA were protected from concanavalin A-induced apoptosis, but were as susceptible as control cells to apoptosis induced by staurosporine and oxidative insults. Therefore, at least two apoptotic pathways in PC12 cells can be discerned by their differential sensitivity to blockade by bcl-2 and crmA. The ability of beta-amyloid (Abeta) to induce apoptosis in these cells was assessed. CrmA transfectants were protected from apoptosis induced by Abeta1-42, but only cells expressing very high levels of bcl-2 were similarly protected. These results suggest that the apoptotic pathway activated by Abeta1-42 in PC12 cells can be differentiated from the apoptotic pathway activated by oxidative insults. Gene transfer experiments also demonstrated that expression of crmA in primary cultures of hippocampal neurons is protective against cell death induced by Abeta1-42. Together these results support the hypothesis that Abeta-induced apoptosis occurs through activation-induced programmed cell death.
Insights
Researchers explored apoptosis in PC12 cells using bcl-2 and crmA. They found distinct apoptotic pathways activated by different insults, including beta-amyloid (Abeta), suggesting Abeta-induced cell death involves activation-induced programmed cell death.
Area of Science:
- Neuroscience
- Cell Biology
- Molecular Biology
Background:
- Apoptosis, or programmed cell death, is crucial for neuronal development and homeostasis.
- Dysregulation of apoptosis is implicated in neurodegenerative diseases like Alzheimer's disease.
- Understanding the specific pathways of apoptosis is key to developing therapeutic interventions.
Purpose of the Study:
- To differentiate apoptotic pathways in PC12 cells using bcl-2 and crmA.
- To investigate the role of these pathways in beta-amyloid (Abeta)-induced apoptosis.
- To explore the potential of crmA as a neuroprotective agent against Abeta toxicity.
Main Methods:
- Generation of stable PC12 cell transfectants expressing bcl-2 or crmA.
- Exposure of transfectants to various apoptotic stimuli (staurosporine, hydrogen peroxide, peroxynitrite, concanavalin A, Abeta1-42).
- Assessment of cell death and apoptosis inhibition.
- Gene transfer experiments in primary hippocampal neurons.
Main Results:
- Bcl-2 conferred resistance to staurosporine and oxidative stress but was less effective against concanavalin A-induced apoptosis.
- CrmA protected against concanavalin A and Abeta1-42 induced apoptosis but not staurosporine or oxidative insults.
- PC12 cells exhibit at least two distinct apoptotic pathways sensitive to bcl-2 and crmA.
- Abeta1-42-induced apoptosis in PC12 cells appears to involve a pathway distinct from oxidative insults.
- CrmA expression protected hippocampal neurons from Abeta1-42 induced cell death.
Conclusions:
- Differential sensitivity to bcl-2 and crmA blockade reveals distinct apoptotic pathways in PC12 cells.
- Abeta1-42 triggers an apoptotic pathway that can be differentiated from oxidative stress-induced apoptosis.
- Abeta-induced apoptosis likely involves activation-induced programmed cell death.
- CrmA shows neuroprotective potential against Abeta toxicity in primary neurons.