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Nerve growth factor induces resistance of PC12 cells to nitric oxide cytotoxicity
1Bio-Organic Research Department, Ciba-Geigy Ltd, Takarazuka, Japan.
Abstract:
Nitric oxide (NO) donors, sodium nitroprusside and NOC 7, caused pheochromocytoma (PC12) cell death in a concentration and time-dependent manner. This cytotoxicity was blocked by the NO trapping agent, oxyhemoglobin. A membrane permeable cGMP analogue had no cytotoxicity in a reasonable concentration. Moreover, the selective inhibitor of cGMP-dependent protein kinase, KT5823, had no effect on NOC 7 cytotoxicity. These results suggest that NO caused PC12 cell death but not through the cGMP pathway. Additionally, this NO-induced PC12 cell death is not accompanied by DNA fragmentation. Nerve growth factor (NGF), which is able to rescue PC12 cells from serum deprivation, failed to protect PC12 cells from NO-induced cell death by acute treatment. However, PC12 cells differentiated by NGF treatment for more than 3 days did not die after NO exposure. The differentiated PC12 cells, but not undifferentiated cells, expressed NO synthase (NOS). NGF-differentiated PC12 cells acquired the resistance to NO, by a mechanism not yet identified, accompanied by the expression of NOS.
Insights
Nitric oxide (NO) causes pheochromocytoma (PC12) cell death via a non-cGMP pathway. NGF-differentiated PC12 cells resist NO toxicity and express nitric oxide synthase (NOS).
Area of Science:
- Neuroscience
- Cell Biology
- Biochemistry
Background:
- Nitric oxide (NO) is a signaling molecule implicated in various cellular processes.
- Pheochromocytoma (PC12) cells are a neuronal cell model used to study neurotrophic factors and cell death.
- The role of NO in PC12 cell death and the involvement of cyclic guanosine monophosphate (cGMP) signaling remain areas of investigation.
Purpose of the Study:
- To investigate the mechanism of nitric oxide (NO)-induced cell death in pheochromocytoma (PC12) cells.
- To determine the role of the cyclic guanosine monophosphate (cGMP) pathway in NO-induced cytotoxicity.
- To examine the effect of nerve growth factor (NGF) differentiation on PC12 cell sensitivity to NO.
Main Methods:
- Treatment of PC12 cells with NO donors (sodium nitroprusside, NOC 7) and assessment of cell viability.
- Use of NO trapping agents (oxyhemoglobin) and cGMP pathway modulators (cGMP analogue, KT5823).
- Evaluation of DNA fragmentation and assessment of PC12 cell differentiation and nitric oxide synthase (NOS) expression following NGF treatment.
Main Results:
- Nitric oxide (NO) donors induced concentration- and time-dependent PC12 cell death, blocked by oxyhemoglobin.
- NO-induced cytotoxicity was independent of the cGMP pathway, as indicated by the lack of effect of a cGMP analogue and a cGMP-dependent protein kinase inhibitor.
- NGF-differentiated PC12 cells exhibited resistance to NO-induced cell death and expressed nitric oxide synthase (NOS), unlike undifferentiated cells.
Conclusions:
- Nitric oxide (NO) induces PC12 cell death through a mechanism independent of the cGMP pathway and without causing DNA fragmentation.
- Nerve growth factor (NGF) differentiation confers resistance to NO-induced cell death in PC12 cells.
- The acquisition of NO resistance in differentiated PC12 cells is associated with the expression of nitric oxide synthase (NOS).