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Mechanisms regulating cytochrome c release in pancreatic mitochondria
I V Odinokova1, K-F Sung, O A Mareninova
1Veterans Affairs Greater Los Angeles Healthcare System and Department of Medicine, David Geffen School of Medicine, University of California at Los Angeles, CA 90073, USA.
Gut
|July 4, 2008
Summary
Reactive oxygen species (ROS) and calcium (Ca2+) mediate acinar cell death in pancreatitis. Mitochondria play a key role, with their stabilization offering a potential therapeutic strategy against pancreatitis severity.
Area of Science:
- Cell Biology
- Biochemistry
- Pathophysiology
Background:
- Mechanisms of acinar cell death in pancreatitis are not fully understood.
- Cytochrome c release is a critical event in pancreatitis-induced apoptosis.
- This study investigates the roles of calcium (Ca2+), mitochondrial membrane potential (ΔΨm), and reactive oxygen species (ROS) in pancreatic cytochrome c release.
Purpose of the Study:
- To assess the regulation of pancreatic cytochrome c release by Ca2+, ΔΨm, and ROS.
- To elucidate the signaling pathways involved in acute pancreatitis.
- To understand the role of mitochondria in acinar cell death during pancreatitis.
Main Methods:
- Utilized isolated rat pancreatic mitochondria and intact acinar cells.
- Stimulated acinar cells with cholecystokinin-8 (CCK-8) to model in vitro acute pancreatitis.
- Measured Ca2+ effects, ΔΨm changes, ROS production, and cytochrome c release.
Main Results:
- Ca2+ induced pancreatic mitochondrial depolarization via a novel mechanism, distinct from liver mitochondria.
- Ca2+-induced depolarization decreased ROS and inhibited cytochrome c release, contrasting with Ca2+ per se which stimulated release.
- In intact cells, ROS and Ca2+ promoted cytochrome c release, caspase activation, and apoptosis, while depolarization inhibited these events.
Conclusions:
- ROS are key mediators of CCK-8-induced apoptotic responses in pancreatic acinar cells.
- Mitochondria are central to the effects of Ca2+ and ROS on acinar cell death.
- Stabilizing mitochondria against ΔΨm loss may mitigate pancreatitis severity.
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