Impact of diabetes-associated lipoproteins on oxygen consumption and mitochondrial enzymes in porcine aortic endothelial cells
Languages of publication
Impairments in mitochondrial function have been proposed to play an important role in the pathogenesis of diabetes. Atherosclerotic coronary artery disease (CAD) is the leading cause of mortality in diabetic patients. Mitochondrial dysfunction and increased production of reactive oxygen species (ROS) are associated with diabetes and CAD. Elevated levels of glycated low density lipoproteins (glyLDL) and oxidized LDL (oxLDL) were detected in patients with diabetes. Our previous studies demonstrated that oxLDL and glyLDL increased the generation of ROS and altered the activities of antioxidant enzymes in vascular endothelial cells (EC). The present study examined the effects of glyLDL and oxLDL on mitochondrial respiration, membrane potential and the activities and proteins of key enzymes in mitochondrial electron transport chain (mETC) in cultured porcine aortic EC (PAEC). The results demonstrated that glyLDL or oxLDL significantly reduced oxygen consumption in Complex I, II/III and IV of mETC in PAEC compared to LDL or vehicle control using oxygraphy. Incubation with glyLDL or oxLDL significantly reduced mitochondrial membrane potential, the activities of mitochondrial ETC enzymes - NADH dehydrogenase (Complex I), succinate cytochrome c reductase (Complex II + III), ubiquinol cytochrome c reductase (Complex III), and cytochrome c oxidase (Complex IV) in PAEC compared to LDL or control. Treatment with oxLDL or glyLDL reduced the abundance of subunits of Complex I, ND1 and ND6 in PAEC. However, the effects of oxLDL on mitochondrial activity and proteins were not significantly different from glyLDL. The findings suggest that the glyLDL or oxLDL impairs mitochondrial respiration, as a result from the reduction of the abundance of several key enzymes in mitochondria of vascular EC, which potentially may lead to oxidative stress in vascular EC, and the development of diabetic vascular complications.
- Bartnik M, Norhammar A, Rydén L (2007) Hyperglycaemia and cardiovascular disease. J Intern Med 262: 145-156.
- Birch-Machin MA, Briggs HL, Saborido AA, Bindoff LA, Turnbull DM (1994) An evaluation of the measurement of the activities of complexes I-IV in the respiratory chain of human skeletal muscle mitochondria. Biochem Med Metab Biol 51: 35-42.
- Ceaser EK, Ramachandran A, Levonen AL, Darley-Usmar VM (2003) Oxidized low-density lipoprotein and 15-deoxy-Δ12,14-PGJ2 increase mitochondrial complex I activity in endothelial cells. Am J Physiol Heart Circ Physiol 285: H2298-H2308.
- Chowdhury SK, Drahota Z, Floryk D, Calda P, Houstek J (2000) Activities of mitochondrial oxidative phosphorylation enzymes in cultured amniocytes. Clin Chim Acta 298: 157-173.
- Chowdhury SK, Gemin A, Singh G (2005) High activity of mitochondrial glycerophosphate dehydrogenase and glycerophosphate-dependent ROS generation in prostate cancer cell lines. Biochem Biophys Res Commun 333: 1139-1145.
- Chowdhury SK, Raha S, Tarnopolsky MA, Singh G (2007) Increased expression of mitochondrial glycerophosphate dehydrogenase and antioxidant enzymes in prostate cancer cell lines/cancer. Free Radic Res 41: 1116-1124.
- DiMauro S, Andreu AL (2000) Mutations in mtDNA: are we scraping the bottom of the barrel? Brain Pathol 10: 431-441.
- Floryk D, Houstĕk J (1999) Tetramethyl rhodamine methyl ester (TMRM) is suitable for cytofluorometric measurements of mitochondrial membrane potential in cells treated with digitonin. Biosci Rep 19: 27-34.
- Kirkland RA, Franklin JL (2001) Evidence for redox regulation of cytochrome c release during programmed neuronal death: antioxidant effects of protein synthesis and caspase inhibition. J Neurosci 21: 1949-1963.
- Kowluru RA, Kowluru V, Xiong Y, Ho YS (2006) Overexpression of mitochondrial superoxide dismutase in mice protects the retina from diabetes-induced oxidative stress. Free Radic Biol Med 41: 1191-1196.
- Lyons TJ (1993) Glycation and oxidation: a role in the pathogenesis of atherosclerosis. Am J Cardiol 71: 26B-31B.
- Masaki H, Atsumi T, Sakurai H (1995) Detection of hydrogen peroxide and hydroxyl radicals in murine skin fibroblasts under UVB irradiation. Biochem Biophys Res Commun 206: 474-479.
- Munusamy S, Saba H, Mitchell T, Megyesi JK, Brock RW, Macmillan-Crow LA (2009) Alteration of renal respiratory Complex-III during experimental type-1 diabetes. BMC Endocr Disord 9: 2.
- Ren S, Man RY, Angel A, Shen GX (1997) Oxidative modification enhances lipoprotein(a)-induced overproduction of plasminogen activator inhibitor-1 in cultured vascular endothelial cells. Atherosclerosis 128: 1-10.
- Ren S, Shatadal S, Shen GX (2000) Protein kinase C-beta mediates lipoprotein-induced generation of PAI-1 from vascular endothelial cells. Am J Physiol Endocrinol Metab 278: E656-E662.
- Roy Chowdhury SK, Sangle GV, Xie X, Stelmack GL, Halayko AJ, Shen GX (2010) Effects of extensively oxidized low-density lipoprotein on mitochondrial function and reactive oxygen species in porcine aortic endothelial cells. Am J Physiol Endocrinol Metab 298: E89-E98.
- Rustin PD, Chretien T, Bourgeron B, Gérard A, Rötig JM, Saudubray JM, Munnich A (1994) Biochemical and molecular investigations in respiratory chain deficiencies. Clin Chim Acta 228: 35-51.
- Sangle GV, Chowdhury SK, Xie X, Stelmack GL, Halayko AJ, Shen GX (2010) Impairment of mitochondrial respiratory chain activity in aortic endothelial cells induced by glycated low-density lipoprotein. Free Radic Biol Med 48: 781-790.
- Shen XY, Hamilton TA, Dicorleto PE (1989) Lipopolysaccharide-induced expression of the competence gene KC in vascular endothelial cells is mediated through protein kinase C. J Cell Physiol 140: 44-51.
- Srere PA (1969) Citrate synthase. Methods Enzymol 13: 3-26.
- Tsimikas S, Bergmark C, Beyer RW, Patel R, Pattison J, Miller E, Juliano J, Witztum JL (2003) Temporal increases in plasma markers of oxidized low-density lipoprotein strongly reflect the presence of acute coronary syndromes. J Am Coll Cardiol 41: 360-370.
- Vondra K, Rath R, Bass A, Slabochová Z, Teisinger J, Vitek V (1977) Enzyme activities in quadriceps femoris muscle of obese diabetic male patients, Diabetologia 13: 527-529.
- Zhang J, Ren S, Sun D, Shen GX (1998) Influence of glycation on LDL-induced generation of fibrinolytic regulators in vascular endothelial cells. Arterioscler Thromb Vasc Biol 18: 1140-1148.
- Zhao R, Shen GX (2005) Functional modulation of antioxidant enzymes in vascular endothelial cells by glycated LDL. Atherosclerosis 179: 277-284.
- Zhao R, Ma X, Xie X, Shen GX (2009) Involvement of NADPH oxidase in oxidized LDL-induced upregulation of heat shock factor-1 and plasminogen activator inhibitor-1 in vascular endothelial cells. Am J Physiol Endocrinol Metab 297: E104-E111.
Publication order reference