The major source of energy for myocardial function is the oxidation of fatty acids in cardiac mitochondria. Our long range goal is to define mitochondrial biogenesis, particularly the coordinate regulation of nuclear genes encoding mitochondrial proteins, because expression of these genes changes during development and differs among tissues with various energy requirements. The cardiovascular system is an ideal model to explore regulation of nuclear genes encoding mitochondrial proteins because (i) of the heart's extraordinary energy requirements and (ii), during the transition from fetal to post-natal life, the mammalian heart switches from anaerobic, glycolytic energy production to aerobic oxidative phosphorylation with fatty acids as the major energy source. We postulate that a set of transcription factors regulates the coordinated changes in mitochondrial protein gene expression which occur with the rapid induction of mitochondrial number in the perinatal period. Our proposed focus is regulation of the two human mitochondrial creatine kinase (MtCK) genes. The ubiquitous MtCK gene is expressed in many tissues including vascular smooth muscle, but the sarcomeric MtCK gene is expressed only in heart and skeletal muscle. We will test the creatine phosphate (CP) shuttle hypothesis, which proposes that energy produced in mitochondria is transferred as CP to the myofibrillar apparatus and serves as the source of energy for myocardial contraction.
Our specific aims are to (1) delineate tissue-specific regulatory sequences in the human MtCK genes by transient transfection in vitro; (2) characterize changes in endogenous mouse uMtCK and sMtCK gene expression during development by in situ hybridization and immunocytochemistry; (3) test putative tissue- specific regulatory elements for both the uMtCK and sMtCK genes in transgenic mice and by direct myocardial injection; (4) characterize regulatory elements mediating changes in expression of the uMtCK and sMtCK genes during development with transgenic mice; (5) determine the functional roles of the uMtCK and sMtCK genes by disruption of both mouse MtCK genes with homologous recombination to definitively test the CP shuttle hypothesis; and (6) Isolate and characterize transcription factors which bind to regulatory regions in the human sMtCK and uMtCK genes. Understanding regulation of expression of nuclear genes encoding these cardiac mitochondrial energy-producing proteins is essential to defining normal mammalian cardiovascular development and the pathophysiology of hypoxia (as in cyanotic congenital heart disease), hypertrophy, and ischemia and to delineating molecular defects in mitochondrial proteins which cause cardiomyopathy and sudden infant death.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Project (R01)
Project #
5R01HL052350-09
Application #
6403251
Study Section
Cardiovascular and Pulmonary Research A Study Section (CVA)
Program Officer
Pearson, Gail D
Project Start
1994-04-01
Project End
2003-08-30
Budget Start
2001-04-01
Budget End
2003-08-30
Support Year
9
Fiscal Year
2001
Total Cost
$306,151
Indirect Cost
Name
Vanderbilt University Medical Center
Department
Pediatrics
Type
Schools of Medicine
DUNS #
004413456
City
Nashville
State
TN
Country
United States
Zip Code
37212
Boero, J; Qin, W; Cheng, J et al. (2003) Restricted neuronal expression of ubiquitous mitochondrial creatine kinase: changing patterns in development and with increased activity. Mol Cell Biochem 244:69-76
Khuchua, Z; Wozniak, D F; Bardgett, M E et al. (2003) Deletion of the N-terminus of murine map2 by gene targeting disrupts hippocampal ca1 neuron architecture and alters contextual memory. Neuroscience 119:101-11
Shen, W; Tian, R; Saupe, K W et al. (2001) Endogenous nitric oxide enhances coupling between O2 consumption and ATP synthesis in guinea pig hearts. Am J Physiol Heart Circ Physiol 281:H838-46
Cave, A C; Ingwall, J S; Friedrich, J et al. (2000) ATP synthesis during low-flow ischemia: influence of increased glycolytic substrate. Circulation 101:2090-6
Mathur, A; Sims, H F; Gopalakrishnan, D et al. (1999) Molecular heterogeneity in very-long-chain acyl-CoA dehydrogenase deficiency causing pediatric cardiomyopathy and sudden death. Circulation 99:1337-43
Qin, W; Khuchua, Z; Boero, J et al. (1999) Oxidative myocytes of heart and skeletal muscle express abundant sarcomeric mitochondrial creatine kinase. Histochem J 31:357-65
Tian, R; Miao, W; Spindler, M et al. (1999) Long-term expression of protein kinase C in adult mouse hearts improves postischemic recovery. Proc Natl Acad Sci U S A 96:13536-41
Tian, R (1998) Thermodynamic limitation for the sarcoplasmic reticulum Ca(2+)-ATPase contributes to impaired contractile reserve in hearts. Ann N Y Acad Sci 853:322-4
Tian, R; Halow, J M; Meyer, M et al. (1998) Thermodynamic limitation for Ca2+ handling contributes to decreased contractile reserve in rat hearts. Am J Physiol 275:H2064-71
Khuchua, Z A; Qin, W; Boero, J et al. (1998) Octamer formation and coupling of cardiac sarcomeric mitochondrial creatine kinase are mediated by charged N-terminal residues. J Biol Chem 273:22990-6

Showing the most recent 10 out of 15 publications