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Updated: Aug 1, 2026
Viability Assays for Cells in Culture
Published on: January 20, 2014
Inhibition of MG132-induced mitochondrial dysfunction and cell death in PC12 cells by 3-morpholinosydnonimine
Chung Soo Lee1, Eun Sook Han, Eon Sob Park
1Department of Pharmacology, College of Medicine, Chung-Ang University, Seoul 156-756, South Korea. leecs@cau.ac.kr
Abstract:
The effect of 3-morpholinosydnonimine (SIN-1) against the cytotoxicity of MG132, a proteasome inhibitor, in differentiated PC12 cells was assessed by measuring the effect on the mitochondrial membrane permeability. Treatment of PC12 cells with MG132 resulted in the nuclear damage, decrease in the mitochondrial transmembrane potential, cytosolic accumulation of cytochrome c, activation of caspase-3, increase in the formation of reactive oxygen species (ROS), and depletion of GSH. Addition of SIN-1, a producer of nitric oxide (NO) and superoxide, differentially reduced the MG132-induced cell death and GSH depletion concentration dependently with a maximal inhibitory effect at 150 microM. Carboxy-PTIO, superoxide dismutase, Mn-TBAP, and ascorbate prevented the inhibitory effect of SIN-1 on the cytotoxicity of MG132. SIN-1 inhibited the MG132-induced change in the mitochondrial membrane permeability, ROS formation and decrease in GSH contents in PC12 cells. S-nitroso-N-acetyl-DL-penicillamine reduced the MG132-induced cell death in PC12 cells, whereas peroxynitrite and H2O2 did not affect the cytotoxicity of MG132. The results suggest that NO and superoxide liberated from SIN-1 exert an inhibitory effect against the cytotoxicity of MG132. SIN-1 may inhibit the MG132-induced viability loss in PC12 cells by suppressing change in the mitochondrial membrane permeability that is associated with oxidative damage.
Insights
3-morpholinosydnonimine (SIN-1) protects PC12 cells from proteasome inhibitor MG132-induced damage. SIN-1
Area of Science:
- Neuroscience
- Cell Biology
- Biochemistry
Background:
- Proteasome inhibitors like MG132 induce cellular damage.
- Mitochondrial dysfunction and oxidative stress are key mechanisms in MG132 cytotoxicity.
- PC12 cells are a neuronal model used to study cell death pathways.
Purpose of the Study:
- To investigate the protective effects of 3-morpholinosydnonimine (SIN-1) against MG132-induced cytotoxicity in differentiated PC12 cells.
- To elucidate the role of nitric oxide (NO) and superoxide in mediating these protective effects.
- To determine the impact of SIN-1 on mitochondrial membrane permeability and oxidative stress markers.
Main Methods:
- PC12 cells were treated with MG132 and varying concentrations of SIN-1.
- Mitochondrial membrane potential, reactive oxygen species (ROS) formation, and glutathione (GSH) levels were measured.
- Inhibitory effects of SIN-1 were assessed using scavengers like Carboxy-PTIO and superoxide dismutase.
Main Results:
- MG132 induced nuclear damage, mitochondrial dysfunction, ROS production, and GSH depletion.
- SIN-1 significantly reduced MG132-induced cell death and GSH depletion in a dose-dependent manner.
- SIN-1's protective effects were abolished by superoxide and NO scavengers, implicating these molecules in the mechanism.
Conclusions:
- Nitric oxide and superoxide released from SIN-1 protect PC12 cells from MG132 cytotoxicity.
- SIN-1 mitigates MG132-induced cell death by preserving mitochondrial membrane permeability and reducing oxidative damage.
- These findings highlight a potential therapeutic strategy involving NO donors against proteasome inhibitor-induced neurotoxicity.
