New readily accessible systemic redox biomarkers are needed to understand the biological roles reactive oxygen species (ROS) play in humans because overtly flawed, technically fraught, and unspecific assays severely hamper translational progress. The antibody-linked oxi-state assay (ALISA) makes it possible to develop valid ROS-sensitive target-specific protein thiol redox state biomarkers in a readily accessible microplate format. Here, we used a maximal exercise bout to disrupt redox homeostasis in a physiologically meaningful way to determine whether the catalytic core of the serine/threonine protein phosphatase PP2A is a candidate systemic redox biomarker in human erythrocytes. We reasoned that: constitutive oxidative stress (e.g., haemoglobin autoxidation) would sensitise erythrocytes to disrupted ion homeostasis as manifested by increased oxidation of the ion regulatory phosphatase PP2A. Unexpectedly, an acute bout of maximal exercise lasting ~16 min decreased PP2A-specific reversible thiol oxidation (redox ratio, rest: 0.46; exercise: 0.33) without changing PP2A content (rest: 193 pg/ml; exercise: 191 pg/ml). The need for only 3–4 μl of sample to perform ALISA means PP2A-specific reversible thiol oxidation is a capillary—fingertip blood—compatible candidate redox biomarker. Consistent with biologically meaningful redox regulation, thiol reductant-inducible PP2A activity was significantly greater (+10%) at rest compared to exercise. We establish a route to developing new readily measurable protein thiol redox biomarkers for understanding the biological roles ROS play in humans.
|Number of pages||6|
|Journal||Free Radical Biology and Medicine|
|Early online date||22 Feb 2022|
|Publication status||Published (in print/issue) - 31 Mar 2022|
Bibliographical noteFunding Information:
We acknowledge the participants who made the present work possible and thank the EU INTERREG VA programme (D.C.) and Highlands and Islands Enterprise ( HMS 9533763 , J.N.C and D.C.) for funding the present work. The graphical abstract, Fig. 1 , and Fig. 3 D were created using BioRender ( www.Biorender.com ) and exported with the appropriate publication license.
© 2022 Elsevier Inc.
- Oxidative stress
- Redox signalling
- Protein thiol