Tepp 2013 Abstract MiP2013
|Tepp K, Anmann T, Varikmaa M, Timohhina N, Shevchuk I, Chekulayev V, Saks V, Kaambre T (2013) Bioenergetic aspects of postnatal development of cardiac cells: Formation of structure-function relationship. Mitochondr Physiol Network 18.08.|
In adult cardiac muscle cells mitochondria are positioned in a crystal-like pattern and are integrated into functional complexes, intracellular energetic units (ICEU), which regulate energy metabolism in striated muscles . In postnatal cardiomyocytes the cellular cytoarchitecture is significantly less organized, ICEUs have not been established and these cells are relatively more dependent on anaerobic glycolysis . In this work we demonstrate that during heart postnatal development exhaustive changes are taking place both at the functional and structural level of energy metabolism. The main methods used were confocal microscopy and respirometry with the Oxygraph-2k.
We show the formation of a regular arrangement of the mitochondria and cytoskeletal alterations in parallel to the maturation of energy transfer systems of mitochondrial metabolism. The affinity for ADP of mitochondrial respiration decreased while localization of mitochondria became progressively more organized within the cellular interior. At birth the Km’ for ADP was relatively low (75.0±4.5 µM; 3-day old rat cardiomyocytes), and then steadily increased to the adult level (317±30 µM; 84 days). This reflects the formation of increased diffusion restrictions for ADP and is a manifestation of higher regulation of energy transfer. Simultaneously, the creatine kinase system is becoming progressively more capacitive in mediating the feedback regulation between ATP consumption in the cytosol with production by mitochondria. These functional alterations are accompanied by changes in structural organization of mitochondria both relative to myofibrils and to cytoskeletal proteins like aIV and βII tubulin - these proteins could participate in the regulation of voltage dependant anion channel (VDAC) permeability for adenine nucleotides. Functional interactions between mitochondria and components of the cytoskeleton in cardiac cells are necessary prerequisites for highly organized metabolic networks characteristic of adult cardiomyocytes.
Labels: MiParea: Respiration, mt-Structure;fission;fusion, Developmental biology
Organism: Rat Tissue;cell: Heart Preparation: Intact cells, Permeabilized cells, Permeabilized tissue
Regulation: Aerobic glycolysis, ADP, Ion;substrate transport, PCr;Cr Coupling state: OXPHOS Pathway: N, S, CIV HRR: Oxygraph-2k
1 - Laboratory of Bioenergetics, National Institute of Chemical Physics and Biophysics, Tallinn, Estonia; 2 - Laboratory of Fundamental and Applied Bioenergetics, Joseph Fourier University, Grenoble, France. - Email: [email protected]
- Saks V, Kuznetsov AV, Gonzalez-Granillo M, Tepp K, Timohhina N, Karu-Varikmaa M, Kaambre T, Dos Santos P, Boucher F, Guzun R (2012) Intracellular energetic units regulate metabolism in cardiac cells. J Mol Cell Cardiol 52: 419-436.
- Piquereau J, Novotova, Fortin MD, Garnier A, Ventura-Clapier R, Veksler V, Joubert F (2010) Postnatal development of mouse heart: Formation of energetic microdomains. J Physiol 588: 2443-2454.