Control of Mitochondrial Dynamics by Fas-induced Caspase-8 Activation in Hippocampal Neurons

Area of Science:

• Cell Biology
• Molecular Biology
• Neuroscience

Background:

• Apoptosis occurs via mitochondrial and cytosolic pathways.
• Mitochondrial pathway activation causes mitochondrial fragmentation, inhibiting it can prevent cell death.
• Mitochondrial events in the cytosolic pathway are poorly understood.

Purpose of the Study:

• To investigate mitochondrial events following activation of the cytosolic pathway.
• To determine the role of caspase-8 in Fas-induced mitochondrial fragmentation.

Main Methods:

• Treatment of hippocampal primary neurons and HT-22 cell lines with Fas-activating antibody.
• Monitoring of mitochondrial fragmentation and caspase activation (caspase-8 and caspase-3).
• Inhibition of caspase-8 to assess its role in mitochondrial fragmentation.

Main Results:

• Fas antibody induced mitochondrial fragmentation without causing cell death.
• Rapid activation of caspase-8 was observed, but not of executioner caspase-3.
• Blocking caspase-8 prevented Fas antibody-induced mitochondrial fragmentation.

Conclusions:

• The cytosolic pathway, activated by death receptors, induces mitochondrial fission.
• This process is dependent on caspase-8 activation.
• Caspase-8 plays a key role in regulating mitochondrial dynamics during apoptosis signaling.