Abstract
Reactive Oxygen Species Alter Activation Of Cardiac Myofilaments And Modify Sarcomeric Proteins
Biophysical journal, Vol.96(3 Suppl 1), pp.497-497a
02/2009
DOI: 10.1016/j.bpj.2008.12.2565
Abstract
The generation of reactive oxygen species [ROS] such as hydrogen peroxide [H2O2] is elevated in acute and chronic cardiac pathophysiology. Post-translational oxidative modification of sarcomeric proteins important to cardiac function, such as actin and tropomyosin [Tm], represents a possible mechanism by which ROS may induce changes in cardiac function. Here we present data that test the hypothesis that ROS modify the function of ventricular muscle through oxidation of sarcomeric components. We directly exposed cardiac muscle to oxidation by treatment of detergent-extracted myofibril bundles from murine papillary muscles with 2.5 mM H2O2. From the same hearts, we prepared homogenates of the ventricular sarcomeric proteins; each sample was divided and processed with and without exposure to H2O2. We compared the oxidation state of the proteins, employing electrophoresis to analyze the formation of reduction-sensitive disulfides by oxidized cysteine residues. Compared to untreated fiber bundles, those treated with H2O2 showed significantly blunted cooperative activation in response to strong actin-myosin cross-bridge binding, as measured by addition of N-ethylmaleimide modified myosin sub-fragment 1 [NEM-S1]. Cross-bridge dependent effects are important for full activation of the cardiac thin filament and are believed to control the kinetics of ejection and relaxation. Results from “diagonal” gels (SDS-PAGE run successively under non-reducing and reducing conditions) revealed reduction-sensitive products which were more abundant in peroxide-treated compared to untreated tissue samples. Western immuno-blot analysis confirmed that these products contained actin and Tm. Overall, our findings represent evidence for the ROS-induced oxidation of myofibrillar proteins along with impairment in cardiac muscle function. Investigation of whether the endogenously generated ROS observed in pathological settings have similar effects in vivo will aid in assessing the significance of these modifications, and may suggest a therapeutic target.
Details
- Title: Subtitle
- Reactive Oxygen Species Alter Activation Of Cardiac Myofilaments And Modify Sarcomeric Proteins
- Creators
- Benjamin S. Avner - University of Illinois ChicagoR. John Solaro - University of Illinois Chicago
- Resource Type
- Abstract
- Publication Details
- Biophysical journal, Vol.96(3 Suppl 1), pp.497-497a
- DOI
- 10.1016/j.bpj.2008.12.2565
- ISSN
- 0006-3495
- eISSN
- 1542-0086
- Publisher
- Elsevier
- Language
- English
- Date published
- 02/2009
- Academic Unit
- Internal Medicine
- Record Identifier
- 9985241077402771
Metrics
1 Record Views