Comparative analysis of the bioenergetics of adult cardiomyocytes and nonbeating HL-1 cells: respiratory chain activities, glycolytic enzyme profiles, and metabolic fluxes.
Comparative analysis of the bioenergetic parameters of adult rat cardiomyocytes (CM) and HL-1 cells with very different structure but similar cardiac phenotype was carried out with the aim of revealing the importance of the cell structure for regulation of its energy fluxes. Confocal microscopic analysis showed very different mitochondrial arrangement in these cells. The cytochrome content per milligram of cell protein was decreased in HL-1 cells by a factor of 7 compared with CM. In parallel, the respiratory chain complex activities were decreased by 4-8 times in the HL-1 cells. On the contrary, the activities of glycolytic enzymes, hexokinase (HK), and pyruvate kinase (PK) were increased in HL-1 cells, and these cells effectively transformed glucose into lactate. At the same time, the creatine kinase (CK) activity was significantly decreased in HL-1 cells. In conclusion, the results of this study comply with the assumption that in contrast to CM in which oxidative phosphorylation is a predominant provider of ATP and the CK system is a main carrier of energy from mitochondria to ATPases, in HL-1 cells the energy metabolism is based mostly on the glycolytic reactions coupled to oxidative phosphorylation through HK.
Monge
Claire
C
INSERM U884, Laboratory of Fundamental and Applied Bioenergetics, Joseph Fourier University, Grenoble, France.
Beraud
Nathalie
N
Tepp
Kersti
K
Pelloux
Sophie
S
Chahboun
Siham
S
Kaambre
Tuuli
T
Kadaja
Lumme
L
Roosimaa
Mart
M
Piirsoo
Andres
A
Tourneur
Yves
Y
Kuznetsov
Andrey V
AV
Saks
Valdur
V
Seppet
Enn
E
D000244:Adenosine Diphosphate / Q000378:metabolism; D000818:Animals; D002460:Cell Line; D003402:Creatine Kinase / Q000378:metabolism; D004579:Electron Transport; D004734:Energy Metabolism; D006019:Glycolysis; D006593:Hexokinase / Q000378:metabolism; D051379:Mice; D032383:Myocytes, Cardiac / Q000378:metabolism*; D011770:Pyruvate Kinase / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar
D000244:Adenosine Diphosphate; D006593:Hexokinase; D011770:Pyruvate Kinase; D003402:Creatine Kinase