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Actin polymerization in cellular oxidant injury
D B Hinshaw1, J M Burger, T F Beals
1Department of Surgery, VA Medical Center, Ann Arbor, Michigan 48105.
Archives of Biochemistry and Biophysics
|August 1, 1991
Summary
Oxidative stress triggers actin polymerization in cells, independent of microfilament breakdown. This actin assembly is linked to cellular sulfhydryl oxidation, not glutathione levels.
Area of Science:
- Cell Biology
- Biochemistry
- Oxidative Stress Research
Background:
- Cellular exposure to oxidants causes ATP-dependent microfilament disruption.
- This disruption does not necessitate a net change in polymerized actin levels.
- However, oxidant-injured cells sometimes show increased polymerized actin, prompting further investigation.
Purpose of the Study:
- To investigate the conditions leading to actin polymerization in oxidant-exposed cells.
- To determine the relationship between sulfhydryl oxidation and actin assembly.
- To differentiate this polymerization from ATP-dependent microfilament disruption.
Main Methods:
- Utilized P388D1 cell line exposed to hydrogen peroxide (H2O2) and diamide.
- Measured oxidized glutathione (GSSG) formation as an indicator of sulfhydryl oxidation.
- Assessed actin polymerization using DNase I and flow cytometry assays.
- Conducted experiments with glutathione (GSH)-depleted cells.
Main Results:
- Significant actin polymerization occurred only under conditions of sulfhydryl oxidation post-oxidant exposure.
- Early and greater sulfhydryl oxidation correlated with increased rate and extent of actin polymerization.
- Actin polymerization was independent of glutathione depletion or absolute GSSG levels.
Conclusions:
- Oxidizing conditions inducing significant cellular sulfhydryl oxidation correlate with actin polymerization.
- This actin assembly process is distinct from the ATP-dependent disruption of microfilaments.
- Sulfhydryl oxidation, rather than glutathione status, appears to be the key factor driving this actin polymerization.