Nitric oxides mediates a shift from early necrosis to late apoptosis in cytokine-treated β-cells that is associated with irreversible DNA damage.
For many cell types, including pancreatic β-cells, nitric oxide is a mediator of cell death; however, it is paradoxical that for a given cell type nitric oxide can induce both necrosis and apoptosis. This report tests the hypothesis that cell death mediated by nitric oxide shifts from an early necrotic to a late apoptotic event. Central to this transition is the ability of β-cells to respond and repair nitric oxide-mediated damage. β-Cells have the ability to repair DNA that is damaged following 24-h incubation with IL-1; however, cytokine-induced DNA damage becomes irreversible following 36-h incubation. This irreversible DNA damage following 36-h incubation with IL-1 correlates with the activation of caspase-3 (cleavage and activity). The increase in caspase activity correlates with reductions in endogenous nitric oxide production, as nitric oxide is an inhibitor of caspase activity. In contrast, caspase cleavage or activation is not observed under conditions in which β-cells are capable of repairing damaged DNA (24-h incubation with cytokines). These findings provide evidence that β-cell death in response to cytokines shifts from an early necrotic process to apoptosis and that this shift is associated with irreversible DNA damage and caspase-3 activation.
Hughes
Katherine J
KJ
The Comprehensive Diabetes Center, Univ. of Alabama Birmingham, 12th Floor Shelby, 1530 3rd Ave. South, Birmingham, AL 35294, USA.
Chambers
Kari T
KT
Meares
Gordon P
GP
Corbett
John A
JA
D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D053148:Caspase 3 / Q000378:metabolism; D016923:Cell Death / Q000187:drug effects*; D002469:Cell Separation; D020552:Comet Assay; D016207:Cytokines / Q000494:pharmacology*; D004249:DNA Damage / Q000502:physiology*; D004260:DNA Repair / Q000187:drug effects; D004734:Energy Metabolism / Q000502:physiology; D004789:Enzyme Activation / Q000187:drug effects / Q000502:physiology; D006801:Humans; D007150:Immunohistochemistry; D066298:In Vitro Techniques; D050417:Insulin-Secreting Cells / Q000187:drug effects*; D007375:Interleukin-1 / Q000037:antagonists & inhibitors / Q000494:pharmacology; D008297:Male; D009336:Necrosis; D009569:Nitric Oxide / Q000494:pharmacology*; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000096:biosynthesis; D051381:Rats; D017207:Rats, Sprague-Dawley; D060888:Real-Time Polymerase Chain Reaction
D016207:Cytokines; D007375:Interleukin-1; D019253:Proto-Oncogene Proteins c-bcl-2; D009569:Nitric Oxide; D053148:Caspase 3