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Oxidative stress differentially modulates phosphorylation of ERK, p38 and CREB induced by NGF or EGF in PC12 cells
1Department of Psychiatry & Behavioral Neurobiology, University of Alabama at Birmingham, Birmingham 35294-0017, USA.
Abstract:
This study assessed if oxidative stress induced by treatment of PC12 cells with H2O2 modulated signaling cascades induced by nerve growth factor (NGF) or epidermal growth factor (EGF) because oxidative stress and impaired growth factor function are associated with aging and aging-associated diseases such as Alzheimer's disease. Phosphorylation of extracellular signal-regulated kinases 1 and 2 (ERK 1/2) and of p38 kinase was rapidly increased after treatment with NGF, EGF, or H2O2, with NGF causing more prolonged increases than the other agents. Pretreatment with H2O2 did not alter phosphorylation of ERK1/2 induced by either growth factor, but increased the phosphorylation of p38 kinase induced by treatment with NGF or EGF alone. CREB phosphorylation at SER 133 was rapidly increased by treatment with either NGF or EGF. Pretreatment with H2O2 reduced CREB phosphorylation induced by either growth factor. This seemed to be a direct effect because H2O2 also inhibited CREB phosphorylation induced by the adenylyl cyclase stimulator forskolin. These results demonstrate that oxidative stress can differentially modulate growth factor-initiated signaling cascades. Furthermore, because CREB is an evolutionarily preserved protein involved in the formation of long term memory, these results indicate a new target of oxidative stress that may be important in disorders involving impaired memory, such as Alzheimer's disease.
Insights
Oxidative stress differentially affects growth factor signaling. Pretreatment with hydrogen peroxide (H2O2) impairs CREB phosphorylation, a key protein for memory formation, suggesting a new target in Alzheimer's disease.
Area of Science:
- Neuroscience
- Cell Biology
- Biochemistry
Background:
- Oxidative stress and impaired growth factor signaling are linked to aging and neurodegenerative diseases like Alzheimer's.
- PC12 cells are a common model for studying neuronal differentiation and signaling pathways.
Purpose of the Study:
- To investigate how oxidative stress (H2O2) modulates signaling cascades initiated by nerve growth factor (NGF) and epidermal growth factor (EGF) in PC12 cells.
- To determine the impact of oxidative stress on key signaling proteins involved in neuronal function and memory.
Main Methods:
- PC12 cells were treated with H2O2, NGF, EGF, and forskolin.
- Western blotting was used to assess the phosphorylation levels of ERK1/2, p38 kinase, and CREB.
- Differential modulation of signaling pathways by oxidative stress was analyzed.
Main Results:
- H2O2 treatment increased p38 kinase phosphorylation induced by NGF or EGF.
- H2O2 pretreatment significantly reduced NGF- or EGF-induced CREB phosphorylation.
- H2O2 directly inhibited CREB phosphorylation, independent of growth factor receptors.
Conclusions:
- Oxidative stress differentially modulates growth factor-induced signaling pathways.
- Impaired CREB phosphorylation by oxidative stress represents a novel mechanism potentially contributing to memory deficits in Alzheimer's disease.
- Targeting oxidative stress may offer therapeutic benefits for memory-related disorders.