Inhibition of p66ShcA redox activity in cardiac muscle cells attenuates hyperglycemia-induced oxidative stress and apoptosis
| Autor: | Leonard G. Meggs, Satya P. Kalra, Maha Abdellatif, Michael G. Dube, Ashwani Malhotra, Virendra S Yadav, Himanshu Vashistha |
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| Rok vydání: | 2009 |
| Předmět: |
Leptin
Male Physiology Apoptosis Mitochondrion medicine.disease_cause Mitochondria Heart Rats Sprague-Dawley Mice Mice Inbred NOD Transduction Genetic Diabetic cardiomyopathy Myocyte Myocytes Cardiac Phosphorylation Cells Cultured bcl-2-Associated X Protein Membrane Potential Mitochondrial Caspase 3 Cardiac muscle Cytochromes c Articles Catalase medicine.anatomical_structure Cardiomyopathies Cardiology and Cardiovascular Medicine Oxidation-Reduction medicine.medical_specialty Programmed cell death Src Homology 2 Domain-Containing Transforming Protein 1 Biology Bcl-2-associated X protein Physiology (medical) Internal medicine medicine Animals Superoxide Dismutase Genetic Therapy medicine.disease Rats Mice Inbred C57BL Disease Models Animal Oxidative Stress Endocrinology Shc Signaling Adaptor Proteins Hyperglycemia Mutation Immunology biology.protein Tumor Suppressor Protein p53 Reactive Oxygen Species Oxidative stress |
| Zdroj: | American Journal of Physiology-Heart and Circulatory Physiology. 296:H380-H388 |
| ISSN: | 1522-1539 0363-6135 |
| Popis: | Apoptotic myocyte cell death, diastolic dysfunction, and progressive deterioration in left ventricular pump function characterize the clinical course of diabetic cardiomyopathy. A key question concerns the mechanism(s) by which hyperglycemia (HG) transmits danger signals in cardiac muscle cells. The growth factor adapter protein p66ShcA is a genetic determinant of longevity, which controls mitochondrial metabolism and cellular responses to oxidative stress. Here we demonstrate that interventions which attenuate or prevent HG-induced phosphorylation at critical position 36 Ser residue (phospho-Ser36) inhibit the redox function of p66ShcA and promote the survival phenotype. Adult rat ventricular myocytes obtained by enzymatic dissociation were transduced with mutant-36 p66ShcA (mu-36) dominant-negative expression vector and plated in serum-free media containing 5 or 25 mM glucose. At HG, adult rat ventricular myocytes exhibit a marked increase in reactive oxygen species production, upregulation of phospho-Ser36, collapse of mitochondrial transmembrane potential, and increased formation of p66ShcA/cytochrome- c complexes. These indexes of oxidative stress were accompanied by a 40% increase in apoptosis and the upregulation of cleaved caspase-3 and the apoptosis-related proteins p53 and Bax. To test whether p66ShcA functions as a redox-sensitive molecular switch in vivo, we examined the hearts of male Akita diabetic nonobese (C57BL/6J) mice. Western blot analysis detected the upregulation of phospho-Ser36, the translocation of p66ShcA to mitochondria, and the formation of p66ShcA/cytochrome- c complexes. Conversely, the correction of HG by recombinant adeno-associated viral delivery of leptin reversed these alterations. We conclude that p66ShcA is a molecular switch whose redox function is turned on by phospho-Ser36 and turned off by interventions that prevent this modification. |
| Databáze: | OpenAIRE |
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