American Journal of Physiology-heart and Circulatory Physiology, 2008
Apoptotic myocyte cell death, diastolic dysfunction and progressive deterioration in LV pump func... more Apoptotic myocyte cell death, diastolic dysfunction and progressive deterioration in LV 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 (CMC). 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 interventions that attenuate or prevent HG-induced phosphorylation at critical position 36 Ser residue (phospho-Ser-36), inhibit the redox function of p66ShcA and promote the survival phenotype. Adult rat ventricular myocytes (ARVM) obtained by enzymatic dissociation were transduced with mutant36 p66ShcA (mu-36) dominant negative expression vector and plated in serum free media (SFM) containing 5 mM or 25 mM glucose. At HG, ARVM exhibit marked increase in reactive oxygen species (ROS) production, upregulation of phospho-Ser-36, collapse of mitochondrial transmembrane potential (Δψm) and increased formation of p66ShcA/cytochrome c complexes. These indices of oxidative stress were accompanied by 40% increase in apoptosis and upregulation of cleaved caspase 3 and the apoptosis related proteins p53 and Bax. To test if p66ShcA functions as a redox sensitive molecular switch in vivo, we examined hearts of male Akita diabtic nonobese (C57BL/6J) mice. Immunoblot analysis detected upregulation of phospho-Ser-36, translocation of p66ShcA to mitochondria and formation of p66ShcA/cytochrome c complexes. Conversely, correction of HG by adenoassociated viral delivery of leptin
American Journal of Physiology-heart and Circulatory Physiology, 2008
Apoptotic myocyte cell death, diastolic dysfunction and progressive deterioration in LV pump func... more Apoptotic myocyte cell death, diastolic dysfunction and progressive deterioration in LV 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 (CMC). 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 interventions that attenuate or prevent HG-induced phosphorylation at critical position 36 Ser residue (phospho-Ser-36), inhibit the redox function of p66ShcA and promote the survival phenotype. Adult rat ventricular myocytes (ARVM) obtained by enzymatic dissociation were transduced with mutant36 p66ShcA (mu-36) dominant negative expression vector and plated in serum free media (SFM) containing 5 mM or 25 mM glucose. At HG, ARVM exhibit marked increase in reactive oxygen species (ROS) production, upregulation of phospho-Ser-36, collapse of mitochondrial transmembrane potential (Δψm) and increased formation of p66ShcA/cytochrome c complexes. These indices of oxidative stress were accompanied by 40% increase in apoptosis and upregulation of cleaved caspase 3 and the apoptosis related proteins p53 and Bax. To test if p66ShcA functions as a redox sensitive molecular switch in vivo, we examined hearts of male Akita diabtic nonobese (C57BL/6J) mice. Immunoblot analysis detected upregulation of phospho-Ser-36, translocation of p66ShcA to mitochondria and formation of p66ShcA/cytochrome c complexes. Conversely, correction of HG by adenoassociated viral delivery of leptin
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Papers by Himanshu Dube