Sylvia Hiller1, Robert DeKroon2, Eric D Hamlett3, Longquan Xu1, Cristina Osorio4, Jennifer Robinette5, Witold Winnik6, Stephen Simington2, Nobuyo Maeda1, Oscar Alzate7, Xianwen Yi8. 1. Department of Pathology and Laboratory Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, NC, United States. 2. Lineberger Comprehensive Cancer Center, The University of North Carolina at Chapel Hill, Chapel Hill, NC, United States. 3. Department of Neurosciences, Medical University of South Carolina, Charleston, SC, United States. 4. Systems Proteomics Center, The University of North Carolina at Chapel Hill, Chapel Hill, NC, United States. 5. Department of Neurosciences, Medical University of South Carolina, Charleston, SC, United States; Systems Proteomics Center, The University of North Carolina at Chapel Hill, Chapel Hill, NC, United States. 6. Proteomic Research Core Unit, NHEERL, U.S. Environmental Protection Agency, Research Triangle Park, NC, United States. 7. Texas A&M Health Science Center, College Station, TX, United States. Electronic address: alzate@medicine.tamhsc.edu. 8. Department of Pathology and Laboratory Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, NC, United States. Electronic address: xyi2000@med.unc.edu.
Abstract
BACKGROUND: S-nitrosylation of mitochondrial enzymes involved in energy transfer under nitrosative stress may result in ATP deficiency. We investigated whether α-lipoic acid, a powerful antioxidant, could alleviate nitrosative stress by regulating S-nitrosylation, which could result in retaining the mitochondrial enzyme activity. METHODS: In this study, we have identified the S-nitrosylated forms of subunit 1 of dihydrolipoyllysine succinyltransferase (complex III), and subunit 2 of the α-ketoglutarate dehydrogenase complex by implementing a fluorescence-based differential quantitative proteomics method. RESULTS: We found that the activities of these two mitochondrial enzymes were partially but reversibly inhibited by S-nitrosylation in cultured endothelial cells, and that their activities were partially restored by supplementation of α-lipoic acid. We show that protein S-nitrosylation affects the activity of mitochondrial enzymes that are central to energy supply, and that α-lipoic acid protects mitochondrial enzymes by altering S-nitrosylation levels. CONCLUSIONS: Inhibiting protein S-nitrosylation with α-lipoic acid seems to be a protective mechanism against nitrosative stress. GENERAL SIGNIFICANCE: Identification and characterization of these new protein targets should contribute to expanding the therapeutic power of α-lipoic acid and to a better understanding of the underlying antioxidant mechanisms.
BACKGROUND: S-nitrosylation of mitochondrial enzymes involved in energy transfer under nitrosative stress may result in ATP deficiency. We investigated whether α-lipoic acid, a powerful antioxidant, could alleviate nitrosative stress by regulating S-nitrosylation, which could result in retaining the mitochondrial enzyme activity. METHODS: In this study, we have identified the S-nitrosylated forms of subunit 1 of dihydrolipoyllysine succinyltransferase (complex III), and subunit 2 of the α-ketoglutarate dehydrogenase complex by implementing a fluorescence-based differential quantitative proteomics method. RESULTS: We found that the activities of these two mitochondrial enzymes were partially but reversibly inhibited by S-nitrosylation in cultured endothelial cells, and that their activities were partially restored by supplementation of α-lipoic acid. We show that protein S-nitrosylation affects the activity of mitochondrial enzymes that are central to energy supply, and that α-lipoic acid protects mitochondrial enzymes by altering S-nitrosylation levels. CONCLUSIONS: Inhibiting protein S-nitrosylation with α-lipoic acid seems to be a protective mechanism against nitrosative stress. GENERAL SIGNIFICANCE: Identification and characterization of these new protein targets should contribute to expanding the therapeutic power of α-lipoic acid and to a better understanding of the underlying antioxidant mechanisms.
Authors: Douglas T Hess; Akio Matsumoto; Sung-Oog Kim; Harvey E Marshall; Jonathan S Stamler Journal: Nat Rev Mol Cell Biol Date: 2005-02 Impact factor: 94.444
Authors: Robert M DeKroon; Cristina Osorio; Jennifer B Robinette; Mihaela Mocanu; Witold M Winnik; Oscar Alzate Journal: J Proteome Res Date: 2011-02-18 Impact factor: 4.466
Authors: Dhanya Venugopalan Nair; M Usha Rani; A Gopala Reddy; B Kala Kumar; M Anudeep Reddy; M Lakshman; U Rajkumar Journal: Vet World Date: 2020-01-27