1. p53 Promotes Cardiac Dysfunction in Diabetic Mellitus Caused by Excessive Mitochondrial Respiration-Mediated Reactive Oxygen Species Generation and Lipid AccumulationClinical Perspective
by Hideo Nakamura, Satoaki Matoba, Eri Iwai-Kanai, Masaki Kimata, Atsushi Hoshino, Mikihiko Nakaoka, Maki Katamura, Yoshifumi Okawa, Makoto Ariyoshi, Yuichiro Mita, Koji Ikeda, Mitsuhiko Okigaki, Souichi Adachi, Hideo Tanaka, Tetsuro Takamatsu, and Hiroaki Matsubara
Circ Heart Fail
Volume 5(1):
January 17, 2012
Copyright © American Heart Association, Inc. All rights reserved.

2. p53 protein was increased and cardiac function was reduced in diabetic hearts.
p53 protein was increased and cardiac function was reduced in diabetic hearts. A, p53 protein was increased 4–8 weeks after streptozotocin (STZ) injection in p53 (+/+) mice (n=10 each). B, Contractile function was declined 4 and 8 weeks after STZ injection in p53 (+/+) diabetic mice, whereas heart function was preserved in p53 (−/−) diabetic mice (n=12 each). C, Alteration of fractional shortening was remarkable at 4weeks in p53 (+/+) mice. **P<0.01 versus p53 (+/+) control; ##P<0.01 versus p53 (−/−).
Hideo Nakamura et al. Circ Heart Fail. 2012;5:
Copyright © American Heart Association, Inc. All rights reserved.

3. Reactive oxygen species (ROS)-induced DNA damage and lipid accumulation were increased in p53 (+/+) diabetes mice.
Reactive oxygen species (ROS)-induced DNA damage and lipid accumulation were increased in p53 (+/+) diabetes mice. Representative 8-OHdG immunostaining (A through D, magnification ×200), oil-red-O staining (E through H, magnification ×400), and electron micrographs (EM, I through L, magnification ×5000) depict the histological appearance of left ventricles from p53 (+/+) and p53 (−/−) mice 4 weeks after STZ injection. A through D, Remarkable ROS damage was detected by 8-OHdG immunostaining in p53 (+/+) diabetic mice. E through H, Lipid accumulation in the myocardium was increased in p53 (+/+) diabetic mice, whereas no increase was observed in p53 (−/−) diabetic mice. I through M, Number of lipid droplets was increased in p53 (+/+) diabetic mice. N, Triglyceride content in the myocardium was increased in p53 (+/+) diabetic mice, although there was no increase in p53 (−/−) diabetic mice. O, Mitochondrial DNA content was not changed after the induction of STZ (n=10 each). **P<0.01 versus p53 (+/+) control.
Hideo Nakamura et al. Circ Heart Fail. 2012;5:
Copyright © American Heart Association, Inc. All rights reserved.

4. Mitochondrial respiration was augmented in diabetic hearts.
Mitochondrial respiration was augmented in diabetic hearts. Mitochondrial respiration was measured with Clark-type electrodes, using isolated cardiac mitochondria. A, There were no changes in state 2 or state 4 respirations. State 3 mitochondrial respiration was upregulated in p53 (+/+) diabetic mice. RC indicates respiratory control ratio. B, Complex IV activity was augmented in p53 (+/+) diabetic mice. C, Mitochondrial complex IV activity was significantly augmented in p53 (+/+) diabetic hearts at 4 and 8 weeks after streptozotocin (STZ) injection, whereas mitochondrial activity of complex I, II, and III was not changed 2–8 weeks after STZ injection (n=10 each). D, Alteration of complex IV activity at 4weeks was notable in p53 (+/+) mice. **P<0.01 versus p53 (+/+) control; ##P<0.01 versus p53 (−/−).
Hideo Nakamura et al. Circ Heart Fail. 2012;5:
Copyright © American Heart Association, Inc. All rights reserved.

5. Synthesis of cytochrome c oxidase 2 (SCO2) protein was increased in p53 (+/+) diabetic heart and modulated lipid metabolism and reactive oxygen species (ROS) generation.
Synthesis of cytochrome c oxidase 2 (SCO2) protein was increased in p53 (+/+) diabetic heart and modulated lipid metabolism and reactive oxygen species (ROS) generation. A, In p53(+/+) diabetic mice, the expressions of SCO2 was increased, whereas no increases were observed in p53(−/−) diabetic mice (n=10 each). ##P<0.01 versus p53 (+/+) control. B, SCO2 overexpression augmented oleate oxidation and residual oleate in myocytes (n=10 each). **P<0.01 versus Ad-LacZ. C, Knockdown of SCO2 reduced oleate oxidation and residual oleate in myocytes (n=10 each). #P<0.05 versus small interfering NS. D, BODIPY-conjugated palmitate was accumulated in SCO2 overexpressing myocytes (n=10 each). *P<0.05 versus Ad-LacZ. E, SCO2 protein increased the ROS generation detected by Mitosox in myocytes (n=10 each). *P<0.05 versus Ad-LacZ. F, ROS stained with MitoSOX (red) were colocalized with MitoTracker (green) (n=10 each).
Hideo Nakamura et al. Circ Heart Fail. 2012;5:
Copyright © American Heart Association, Inc. All rights reserved.

6. Cardiac function and mitochondrial respiration did not change in synthesis of cytochrome c oxidase 2 (SCO2) (+/−) diabetic heart.
Cardiac function and mitochondrial respiration did not change in synthesis of cytochrome c oxidase 2 (SCO2) (+/−) diabetic heart. A, At baseline, SCO2 protein expression in the heart was less in SCO2 (+/−) mice than SCO2 (+/+) mice. SCO2 protein was induced after the injection of streptozotocin (STZ) in SCO2 (+/+) mice. B, Mitochondrial complex IV activity was less in SCO2 (+/−) mice than that in SCO2 (+/+) mice and was not induced in SCO2 (+/−) diabetic mice. C, Reactive oxygen species (ROS)-induced DNA damage, lipid accumulation, and lipid droplets (arrowheads) were not increased in SCO2 (+/−) diabetic mice. D, Contractile function was preserved in SCO2 (+/−) diabetic mice. E, BNP mRNA levels were increased in SCO2 (+/+) diabetic mice, whereas there was no increase in SCO2 (+/−) diabetic mice (n=12 each). **P<0.01 versus SCO2(+/+) control; #P<0.05 versus SCO2 (+/+) control.
Hideo Nakamura et al. Circ Heart Fail. 2012;5:
Copyright © American Heart Association, Inc. All rights reserved.