A 5-year research program is outlined with the broad, long-term objective of elucidating the molecular mechanisms responsible for altered Ca2+ transporter gene expression in patients with cardiac hypertrophy and heart failure. There is now substantial evidence to indicate that expression levels of SERCA2 and NCX1, the major Ca2+ transporters in cardiac muscle, are profoundly altered in the failing human ventricular myocardium. These changes may result in reduced contractile function and increased susceptibility to ventricular arrhythmias. However, the underlying intracellular me4chanisms responsible for these changes, and the signal transduction pathways involved are only now being elucidated.
Four specific aims are outlined to clarify these mechanisms in cultured cardiomyocytes, and related them to what may be occurring in hypertrophy and heart failure in experimental animals and man. First, previous work and preliminary data indicate a critical role of PKC activation in SERCA2 down-regulation during hypertrophy and heart failure. We will therefore use molecular biological techniques to over- express and down-regulate specific PKC isozymes to ascertain which PKC isozymes is responsible. Second, we will characterize the [Ca2+]i and Ras-dependent signaling pathways that regulate SERCA2 gene expression. Studies will focus on the non-receptor protein tyrosine kinase PYK2 that is activated by [Ca2+]i and PKC, and that may link G1- coupled receptor activation to the Ras-Raf-MEK-ERK protein kinase cascade. Third, preliminary data indicate that the 3' untranslated region of the SERCA2 mRNA regulates its stability in response to mechanical and neurohormonal stimuli that activate PKCs. Therefore, a series of experiments is outlined to define the cis-acting sequences and trans-acting factors that are involved. Fourth, we will test the hypothesis that activation of PKCs by either neurohormonal or mechanical stimuli (or their combination) up-regulates NXC1 mRNA and protein levels, and begin to analyze the signaling pathways responsible for these changes. The proposed experiments should substantially contribute to our understanding of the mechanisms responsible for altered Ca2+ transporter gene expression in heart failure Future therapeutic strategies targeted towards prevention or reversal of these changes require a thorough understanding of the responsible intracellular mechanisms.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Project (R01)
Project #
5R01HL063711-02
Application #
6343658
Study Section
Cardiovascular and Pulmonary Research A Study Section (CVA)
Program Officer
Reinlib, Leslie
Project Start
2000-01-10
Project End
2003-12-31
Budget Start
2001-01-01
Budget End
2001-12-31
Support Year
2
Fiscal Year
2001
Total Cost
$320,478
Indirect Cost
Name
Loyola University Chicago
Department
Internal Medicine/Medicine
Type
Schools of Medicine
DUNS #
791277940
City
Maywood
State
IL
Country
United States
Zip Code
60153
Hart, Davin L; Heidkamp, Maria C; Iyengar, Rekha et al. (2008) CRNK gene transfer improves function and reverses the myosin heavy chain isoenzyme switch during post-myocardial infarction left ventricular remodeling. J Mol Cell Cardiol 45:93-105
Heidkamp, Maria C; Iyengar, Rekha; Szotek, Erika L et al. (2007) Protein kinase Cepsilon-dependent MARCKS phosphorylation in neonatal and adult rat ventricular myocytes. J Mol Cell Cardiol 42:422-31
Heidkamp, Maria C; Scully, Brian T; Vijayan, Kalpana et al. (2005) PYK2 regulates SERCA2 gene expression in neonatal rat ventricular myocytes. Am J Physiol Cell Physiol 289:C471-82
Blum, Juliana L; Samarel, Allen M; Mestril, Ruben (2005) Phosphorylation and binding of AUF1 to the 3'-untranslated region of cardiomyocyte SERCA2a mRNA. Am J Physiol Heart Circ Physiol 289:H2543-50
Vijayan, Kalpana; Szotek, Erika L; Martin, Jody L et al. (2004) Protein kinase C-alpha-induced hypertrophy of neonatal rat ventricular myocytes. Am J Physiol Heart Circ Physiol 287:H2777-89
Loeser, Richard F; Forsyth, Christopher B; Samarel, Allen M et al. (2003) Fibronectin fragment activation of proline-rich tyrosine kinase PYK2 mediates integrin signals regulating collagenase-3 expression by human chondrocytes through a protein kinase C-dependent pathway. J Biol Chem 278:24577-85
Bayer, Allison L; Heidkamp, Maria C; Patel, Nehu et al. (2003) Alterations in protein kinase C isoenzyme expression and autophosphorylation during the progression of pressure overload-induced left ventricular hypertrophy. Mol Cell Biochem 242:145-52
Heidkamp, Maria C; Bayer, Allison L; Scully, Brian T et al. (2003) Activation of focal adhesion kinase by protein kinase C epsilon in neonatal rat ventricular myocytes. Am J Physiol Heart Circ Physiol 285:H1684-96
Bayer, Allison L; Heidkamp, Maria C; Howes, Amy L et al. (2003) Protein kinase C epsilon-dependent activation of proline-rich tyrosine kinase 2 in neonatal rat ventricular myocytes. J Mol Cell Cardiol 35:1121-33
Porter, Michael J; Heidkamp, Maria C; Scully, Brian T et al. (2003) Isoenzyme-selective regulation of SERCA2 gene expression by protein kinase C in neonatal rat ventricular myocytes. Am J Physiol Cell Physiol 285:C39-47

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