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Superoxide as a signal for increase in intracellular pH
M Shibanuma1, T Kuroki, K Nose
1Department of Cancer Cell Research, University of Tokyo, Japan.
Journal of Cellular Physiology
|August 1, 1988
Summary
Superoxide plays a key role in regulating intracellular pH (pHi) in U937 cells. Antioxidants like superoxide dismutase (SOD) effectively inhibit the pHi increase induced by various stimuli.
Area of Science:
- Cell Biology
- Biochemistry
- Physiology
Background:
- Intracellular pH (pHi) is a critical cellular parameter.
- The role of reactive oxygen species, specifically superoxide, in pHi regulation is not fully understood.
Purpose of the Study:
- To investigate the involvement of superoxide in the increase of intracellular pH (pHi) in human histiocytic leukemia U937 cells.
- To determine the effect of antioxidants on 4 beta-phorbol-12,13-didecanoate (4 beta-PDD) or serum-induced pHi changes.
Main Methods:
- U937 cells were treated with 4 beta-PDD or serum.
- Antioxidants including superoxide dismutase (SOD), vitamin E, and butylated hydroxyanisole (BHA) were used.
- A superoxide-generating system (xanthine-xanthine oxidase) was employed.
- pHi was measured in stimulated and treated cells.
Main Results:
- 4 beta-PDD and serum rapidly increased pHi in U937 cells.
- Antioxidants (SOD, vitamin E, BHA) inhibited the amiloride-sensitive pHi increase induced by 4 beta-PDD.
- SOD also inhibited serum-induced pHi increases in U937 cells and concanavalin A-stimulated mouse thymocytes.
- Xanthine-xanthine oxidase mimicked the pHi-elevating effects of 4 beta-PDD and serum.
Conclusions:
- Superoxide is a significant mediator of intracellular pH modulation.
- These findings suggest a novel signaling role for superoxide in cellular responses.