The mitochondrion is now emerging as a site in vascular cells capable of regulating redox cell signaling events in the cytosol. The mechanisms through which this occurs are not well understood and are the focus of this proposal. Our recent studies suggest that the induction of the endogenous intracellular antioxidants through the Keap1/Nrf-2 system is modulated by post-translational modification of mitochondrial protein thiols. This is important because it is known that deficiencies of endogenous antioxidant proteins, such as heme oxygenase-1, in the vasculature are associated with increased development of atherosclerotic lesions, while over-expression is protective. Interestingly, we have shown that modification of mitochondrial protein thiols leads to endothelial cell dysfunction by inhibition of the endogenous antioxidant pathway. In addition, mitochondrial thiol modification results in the attenuation of the endothelium-dependent vasorelaxation of aortic rings in response to acetylcholine. Our preliminary data also demonstrate that mitochondrial thiol modification causes a switch in bioenergetic pathways away from mitochondrial oxidative phosphorylation and toward the less efficient glycolytic pathway, potentially contributing to a bioenergetic deficiency. Taken together these findings have led to the hypothesis that modulation of mitochondrial protein thiol and redox status will alter vascular endothelial cell function. This will be tested by pursuit of the following specific aims: 1: Determine the role of mitochondrial protein thiols and redox status in the susceptibility of endothelial cells (EC) to oxidative stress;2: Determine the role of mitochondrial thiol modification and altered redox status in vascular endothelial dysfunction;and 3: Determine the mechanistic role of mitochondrial protein thiol modification in endothelial cell dysfunction during increased mitochondrial oxidative stress in atherosclerotic mouse models. The information gained from the accomplishment of these specific aims will give insight into the role of the mitochondrion, particularly mitochondrial protein thiols, in determining endothelial cell dysfunction associated with atherosclerosis.

Public Health Relevance

Oxidative damage is an early event in the development of diseases associated with inflammation. Mitochondria are in cells are often a target for oxidative damage, and some of the most sensitive sites for this damage are the amino acid residues on proteins that contain reactive protein thiols. This project tests the hypothesis that mitochondrial protein thiols are damaged in atherosclerosis and contribute to vascular dysfunction.

National Institute of Health (NIH)
National Heart, Lung, and Blood Institute (NHLBI)
Research Project (R01)
Project #
Application #
Study Section
Vascular Cell and Molecular Biology Study Section (VCMB)
Program Officer
Liu, Lijuan
Project Start
Project End
Budget Start
Budget End
Support Year
Fiscal Year
Total Cost
Indirect Cost
University of Alabama Birmingham
Schools of Medicine
United States
Zip Code
Smith, M Ryan; Vayalil, Praveen K; Zhou, Fen et al. (2016) Mitochondrial thiol modification by a targeted electrophile inhibits metabolism in breast adenocarcinoma cells by inhibiting enzyme activity and protein levels. Redox Biol 8:136-48
Vayalil, Praveen K; Oh, Joo-Yeun; Zhou, Fen et al. (2015) A novel class of mitochondria-targeted soft electrophiles modifies mitochondrial proteins and inhibits mitochondrial metabolism in breast cancer cells through redox mechanisms. PLoS One 10:e0120460
Wall, S B; Oh, J-Y; Mitchell, L et al. (2015) Rac1 modification by an electrophilic 15-deoxy ?(12,14)-prostaglandin J2 analog. Redox Biol 4:346-54
Wall, Stephanie B; Smith, M Ryan; Ricart, Karina et al. (2014) Detection of electrophile-sensitive proteins. Biochim Biophys Acta 1840:913-22
Bolisetty, Subhashini; Traylor, Amie; Zarjou, Abolfazl et al. (2013) Mitochondria-targeted heme oxygenase-1 decreases oxidative stress in renal epithelial cells. Am J Physiol Renal Physiol 305:F255-64
Higdon, Ashlee; Diers, Anne R; Oh, Joo Yeun et al. (2012) Cell signalling by reactive lipid species: new concepts and molecular mechanisms. Biochem J 442:453-64
Higdon, Ashlee N; Benavides, Gloria A; Chacko, Balu K et al. (2012) Hemin causes mitochondrial dysfunction in endothelial cells through promoting lipid peroxidation: the protective role of autophagy. Am J Physiol Heart Circ Physiol 302:H1394-409
Wall, Stephanie B; Oh, Joo-Yeun; Diers, Anne R et al. (2012) Oxidative modification of proteins: an emerging mechanism of cell signaling. Front Physiol 3:369
Higdon, Ashlee N; Landar, Aimee; Barnes, Stephen et al. (2012) The electrophile responsive proteome: integrating proteomics and lipidomics with cellular function. Antioxid Redox Signal 17:1580-9
Dranka, Brian P; Benavides, Gloria A; Diers, Anne R et al. (2011) Assessing bioenergetic function in response to oxidative stress by metabolic profiling. Free Radic Biol Med 51:1621-35

Showing the most recent 10 out of 11 publications