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An alternative, nonapoptotic form of programmed cell death
S Sperandio1, I de Belle, D E Bredesen
1Buck Institute for Age Research, 8001 Redwood Boulevard, Novato, CA 94945, USA.
Abstract:
The term apoptosis often has been used interchangeably with the term programmed cell death. Here we describe a form of programmed cell death that is distinct from apoptosis by the criteria of morphology, biochemistry, and response to apoptosis inhibitors. Morphologically, this alternative form of programmed cell death appears during development and in some cases of neurodegeneration. Despite its lack of response to caspase inhibitors and Bcl-x(L), we show that this form of cell death is driven by an alternative caspase-9 activity that is Apaf-1-independent. Characterization of this alternative form of programmed cell death should lead to new insight into cell death programs and their roles in development and degeneration.
Insights
Scientists identified a novel programmed cell death pathway distinct from apoptosis. This alternative cell death mechanism, independent of Apaf-1, offers new insights into developmental and neurodegenerative processes.
Area of Science:
- Cellular biology
- Biochemistry
- Developmental biology
Background:
- Programmed cell death is crucial for development and tissue homeostasis.
- Apoptosis is the most studied form of programmed cell death, involving caspases.
- Existing knowledge may not encompass all forms of programmed cell death.
Purpose of the Study:
- To identify and characterize a form of programmed cell death distinct from classical apoptosis.
- To elucidate the molecular mechanisms driving this alternative cell death pathway.
- To explore the role of this novel cell death in development and neurodegeneration.
Main Methods:
- Morphological analysis of cell death.
- Biochemical assays to assess cell death pathways.
- Testing responses to apoptosis inhibitors (caspase inhibitors, Bcl-x(L)).
- Investigating caspase-9 and Apaf-1 involvement.
Main Results:
- A distinct form of programmed cell death was identified, differing morphologically and biochemically from apoptosis.
- This alternative cell death pathway is resistant to common apoptosis inhibitors.
- The pathway is driven by an Apaf-1-independent caspase-9 activity.
- This cell death is observed during development and in neurodegeneration.
Conclusions:
- A novel, apoptosis-distinct programmed cell death pathway exists.
- This pathway utilizes an alternative caspase-9 mechanism.
- Understanding this pathway is key to new insights into cell death regulation in development and disease.